8th Forum On New Materials
FA:P01 Facile Synthesis of Flexible In-plane Graphene Micro-supercapacitor Using Flash Reduction
SEOK HUN KANG, I.G. KIM, B.N. KIM, J.H. SUL, I.K. YOU, Electronics and Telecommunications Research Institute, Daejeon, South Korea
Here we present a simple fabrication method of in-plane graphene micro-supercapacitor using flash light irradiation. Flash light reduction of graphene oxide (GO) is an efficient method of producing high quality reduced graphene oxide (rGO) in room temperature ambient conditions without the help of hazardous reducing agents (e.g. hydrazine, hydrogen iodide). The entire process is low cost and is capable of large scale fabrication. By carefully optimizing the photo-thermal reduction conditions and utilizing shadow mask in a similar manner as for photolithography, all-carbon, monolithic supercapacitor with interdigital finger structure can be fabricated in a simple irradiation step that occurs in less than one second. The thickness of the entire fabricated device is less than a hundred micrometer, making the device highly flexible and thus very useful for variety of applications, including portable and wearable electronics. The as-formed supercapacitor benefits from the in-plane structure, which allows full utilization of high surface area of graphene layers and rapid electrolyte diffusion that results in high energy and power densities.
FA:P04 Low-temperature Growth of Wafer-scale Layered MoS2 by Chemical Vapor Deposition for Flexible Devices
SANG-WOO KANG, JIHUN MUN, CHEGAL WON, Korea Research Institute of Standards and Science (KRISS), Deajeon, South Korea
Diverse research has shown that graphene is a promising candidate for analogues of conventional electronic devices. Although it possesses the extraordinary properties of a high electron mobility, elasticity, heat conductivity, and flexibility, graphene is not suitable for transistor and photonic devices owing to the lack of a bandgap. Molybdenum disulfide (MoS2) has emerged as a new two-dimensional (2D) material owing to its tunable band gap and ambient stability. However, to the best of our knowledge, a feasible method for growing a MoS2 at low temperatures of below 400°C has not yet been reported, as it still requires the sulfurization of MoO3-x at high temperatures ranging from 650 to 850°C. Herein, we report a direct one-step low-temperature (350˚C) CVD process for the growth of layered MoS2 with control of the cluster size and the nucleation sites using Mo(CO)6 and hydrogen sulphide (H2S) as the precursor and reaction gas, respectively.
FA:P05 High Performance Flexible a-IGZO TFTs with Highly Hydroxylated Dielectric Surfaces
YAN SHAO, MEI-NA ZHANG, WEN-JUN LIU, SHI-JIN DING, School of Microelectronics, Fudan University, Shanghai, China
Hydrogen is the most common impurity in In-Ga-Zn-O (IGZO) films, and plays a key role in the performance of the IGZO thin-film transistor (TFT). Our previous work indicated that the IGZO TFT with hydrogen-rich SiO2 gate dielectric demonstrates much better performance than that with hydrogen-poor dielectric in the case of no post-annealing. However, the underlying mechanism is not well known. In this work, a series of experiments are designed and carried out for a deep insight of this phenomenon. The Al2O3 film deposited by thermal atomic layer deposition at 200℃ is chosen as the universal gate dielectric of the back-gate TFT. To obtain the Al2O3 films with different surface O-H bonds, two kinds of treatments (H2 plasma treatment and H2O2 precursor treatment) are used. Subsequently, the IGZO film is deposited on the treated Al2O3 film by magnetic sputter, which is used as the channel of TFT. Therefore, the characteristics of various devices are compared. Further, we investigate the effect of post-annealing on the characteristics of the IGZO TFT, and thus understand the initial states and transformation process of H in the IGZO channel. Based on the above experience, high performance transparent and flexible IGZO TFTs are fabricated on the PI substrate.
FB:P03 Study of Bismuth Triiodide Nanoparticles Synthesis and their Application in Organic-inorganic Hybrid Bulk-heterojunction Solar Cells
L. BETHENCOURT, M.E. PÉREZ, H.Y. BENTOS PEREIRA, L.R. FORNARO, D. OREGGIONI, Grupo de Desarrollo de Materiales y Estudios Ambientales, Departamento de Desarrollo Tecnológico, Centro Universitario Regional del Este, Universidad de la República, Rocha, Rocha, Uruguay; I.M. AGUIAR, M. MOMBRÚ, Grupo de Desarrollo de Materiales y Estudios Ambientales, Área Radioquímica, Facultad de Química, Universidad de la República, Montevideo, Montevideo, Uruguay
We synthesized BiI3 nanoparticles (BiI3-NPs), a nontoxic alternative to hybrid perovskite materials, and studied some of their properties in order to test them as possible electron acceptors in polymeric-inorganic hybrid solar cells with regioregular P3HT as electron donor. BiI3-NPs were obtained by hydrothermal method (HTM) and by hot injection method (HIM), using different stabilizing agents, with/without ligand exchange with aniline (ani), and were characterized by IR spectroscopy, XRD and HR-TEM. We got NPs of 5 nm in size (HTM-ani) and 25 nm (HIM), and a better size dispersion in the first case. The determined BiI3-NPs bandgaps were 1.4-1.6eV. The UV-visible study of BiI3-NPs/P3HT suspensions in chloroform with different quantities of NPs showed that there is a successful coupling between BiI3-NPs and P3HT as was corroborated by UV-visible and SEM-EDS analysis of BiI3-NPs/P3HT layers deposited through spin coating according to the traditional hybrid solar cell configuration (ITO/PEDOT:PSS/active layer). Finally we made non optimized solar cells prototypes employing the BiI3-NPs/P3HT layers and characterized them through J-V curves measured under simulated one-sun A.M.1.5 direct illumination. We obtained better performance for prototypes using BiI3-NPs-ani synthesized by HTM.
FB:P04 Plasmonic Coupling Effects in Metal-based Composites for Photovoltaics
N. BEREZOVSKA, I. DMITRUK, O. YESHCHENKO, V. KOZACHENKO, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine; M. DUSHEYKO, National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine
Two plasmonic systems consisting of a layer of metal nanoparticles (NP) and metal film or metal NPs incorporated in thin photovoltaic semiconductor structure that demonstrate optical phenomena caused by the field of surface plasmons excited in NP are studied. The plasmonic coupling between layer of gold (Au) NP and Aluminum (Al) film affects strong extinction of light in such system. The influence of Al film thickness on the plasmonic coupling of Au NP with Al film have been studied by analyzing the behavior of spectral characteristics of Au NP surface plasmon resonance (SPR) extinction peak on Al film thickness. In particular, an additional non-radiative damping of plasma oscillations in Au NP that leads to decrease of SPR peak causes non-monotonic dependence of light extinction. Such changes of light extinction can be used for simple and efficient tuning of system optical response in plasmonic applications. The incorporation of Au NP into thin p–n junction silicondevices can stimulate efficient transfer of light energy into surface plasmons for efficient light trapping and increase of absorption in extremely thin layers. Photocurrent spectrum of designed Au-Si composite demonstrates the increase relative to silicon sensitivity in the spectral range of SPR in Au.
FB:P05 2D/3D Mixed Perovskite Solar Cells by Low-pressure Vapor-assisted Solution Process
HUNG-HSIANG YEH1, YU-HSIEN CHIANG1, MING-HSIEN LI1, CHUN-JEN SU2, U-SER JENG2, PETER CHEN1, 1Department of Photonics, National Cheng Kung University, Tainan, Taiwan; 2National Synchrotron Radiation Research Center, Hsinchu City, Taiwan
3D hybrid organic-inorganic perovskites (HOIPs) have recently emerged as the promising absorber for solar cells. Theses materials can be fabricated with low-cost solution process or vapor phase reaction. In this study, we explore the fabrication of 2D/3D mixed HOIPs via low-pressure vapor-assisted solution process (LP-VASP). It was found that 2D/3D mixed HOIPs can be formed by vapor-assisted solution deposition process with larger organic cation iodide, phenylethylammonium (PEAI, C8H9NH3I). We mix lead iodide (PbI2) and PEAI in the dimethylformamide (DMF) solvent and then spin coated on the mesoscopic TiO2 deposited FTO substrate. The solid film is transferred into vacuum chamber to react with methylammonium iodide (MAI) vapor under low pressure atmosphere. The ratio of the precursor perovskite layers have been varied to from n = 1 through n = ∞ in the series of (PEA)2(MA)n‑1PbnI3n+1. The stoichiometry of PEAI in perovskite has significant impact on the photoluminescence (PL) intensity and the bandgap of the synthesized film. The scanning electron microscope images show that the PEAI-containing perovskite film has more uniform morphology and larger grain size than that of MAPbI3. The device employing n=40 achieved a champion power conversion efficiency of 19.10 %.
FB:P06 Effective Methods for Improving Device Performance of Organic-inorganic Hybrid Perovskite Solar Cells
YANLIANG LIU1, YONGCHAO MA1, SUNG HEUM PARK1, HO SUEB LEE2, KIWAN JANG2, JUNG HYUN JEONG1, 1Department of Physics, Pukyong National University, Busan, South Korea; 2Department of Physics, Changwon National University, Gyeongsangnam-do, South Korea
In this presentation, we report a simple and effective method for improving the performance of organic-inorganic hybrid perovskite solar cells. By employing a novel hot-air annealing process (HAAP) and a merged annealing method (MA) for preparing the perovskite film, we could successfully enhance the crystallinity of the active layer and improve its photon collection properties. This led to a marked improvement in device performance. Solar cells with the structure indium tin oxide/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)/ CH3NH3PbI3-XClX active layer/[6,6]-phenyl-C61-butyric acid methyl ester/Ca/Al and fabricated using these methods showed significantly improved performance, including higher PCE and fill factor values than those of the device fabricated conventionally. The PCE increased from 9.05 to 15.55% when the HAAP process was used and to 18.55% when the MA were used. Moreover, the devices did not exhibit photocurrent hysteresis, which is always observed in the case of the conventionally fabricated solar cells owing to the charge traps resulting from the low quality of the perovskite film.
FB:P07 One-step Sputtering Process for High-efficiency Cu(In,Ga)Se2 Thin Film Solar Cells
CHIA-HAO HSU,WEI-HAO HO, SHIH-YUAN WEI, CHUNG-HAO CAI,WEI-CHIH HUANG, CHIH-HUANG LAI, Department of Materials Science and Engineering, National Tsing Hua University, HsinChu, Taiwan
In recent years, Cu(In,Ga)Se2 (CIGS)-based thin-film solar cells have been of great interest for their high conversion efficiency among all thin-film polycrystalline solar cells. Efficiency over 20% has been achieved by three-stage co-evaporation in laboratory scale. In industry, post-selenization of metallic precursors has drawn more attention due to its feasibility for mass-production with mini-module efficiency over 17% and the large capacity announced by Solar Frontier. In general, high performance CIGS cells are fabricated under the conditions with sufficient or even excess Se supply. However, excess supply of Se usually causes problems for mass production, for example, the maintenance of the processing chamber due to the Se residual or the environmental concern due to the toxicity of H2Se. To address these issues and to simplify the fabrication process, we demonstrate a simple approach by sputtering from a single quaternary target with the cell efficiency of 14% without selenization. We will discuss the effects of target composition, Na/K incorporation and Se content on the CIGS cell performance by using this novel one-step sputtering process.
FC:P01 Beyond Photoelectrochemical Water Splitting
B. MEI, G. MUL, B. SEGER, PCS Group, MESA+ Institute for Nanotechnology, University of Twente, Enschede, Netherlands; Department of Physics, Technical University of Denmark, Kgs. Lyngby, Denmark
Solar hydrogen produced by photoelectrochemical water splitting in an integrated two-photon tandem device is assumed to play a dominant role in various energy storage scenarios. While water splitting to hydrogen and oxygen is an excellent process from a global energy perspective implementation of functional devices will likely be hampered by the predicted costs of produced hydrogen. In this work we will discuss the feasibility of the co-production of valuable chemicals such as halides or H2O2 concomitant with H2 production. Our modelling results suggest that solar-to-hydrogen efficiencies of tandem devices producing Br2, Cl2, or H2O2 can be as high or even higher than for similar devices evolving O2. We will highlight certain efficiency trends, and furthermore it will be shown that the low thermodynamic potential from HBr splitting allows for efficiencies from a single photoabsorber on par with that of a tandem device.
FC:P02 Intermediate Temperature Electro-reforming (ITER)
M.V. PAGLIARO1,2, M. BELLINI1, H.A. MILLER1, W. OBERHAUSER1, M.G. FOLLIERO1,2, A. MARCHIONNI1, J. FILIPPI1, F. VIZZA1, 1ICCOM - CNR, Sesto Fiorentino (Firenze), Italy; 2Dipartimento di Chimica, Università degli Studi di Siena, Siena, Italy
The electro-oxidation of alcohols at intermediate temperatures (100-250°C) in devices like Direct Alcohol Fuel Cells (DAFCs) and Alcohol Electro-Reformers (ER) is an essentially unexplored field. ER and DAFCs are more efficient devices using strong alkaline environments due to faster alcohol oxidation kinetics and lower corrosion of the cell components, anyway the partial oxidation of alcohols to carboxylates at high pH limits their energy efficiency. We have set up an electrochemical autoclave to study, for the first time, the electrooxidation of alcohols in 2m aqueous KOH at T < 180°C. We have synthesized nanostructured palladium-based catalysts supported on nickel foam. The 3D structure of these catalysts guarantees fast mass transport of the alcohol fuel in the liquid phase and enhances gas permeability. These catalysts are electrochemically characterized both in half-cells and in a complete Intermediate Temperature ER. The Pd catalysts are used as anodes and are coupled with a nanostructured NiCoP@Nifoam cathode for the hydrogen evolution reaction. Alcohol electroreforming at temperatures over 100°C in a pressurized vessel, couples the advantages of increased catalyst’s activity and selectivity with the production of pure and safe pressurized hydrogen.
FC:P04 Energy Efficient Production of Fuels and Formate by CO2 Electroreduction on Copper Nanostructures
J. FILIPPI1, M. BEVILACQUA1, M. BELLINI1, M. FOLLIERO1,2, A. MARCHIONNI1, H.A. MILLER1, M. PAGLIARO1,2, F. VIZZA1, 1ICCOM - CNR, Sesto Fiorentino, FI, Italy; 2Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
The electroreduction of carbon dioxide is a promising candidate for promoting high energy density storage processes and providing alternative preparation routes for fuels, energy vectors, and chemicals. The electrochemical reduction of CO2 is an energy-intensive process requiring extensive studies on electrocatalytic structures. Copper-based electrocatalysts have the almost unique characteristic to reduce carbon dioxide to C1-C3 hydrocarbons and alcohols but the activities have to be improved. In this study, plain metallic copper is modified by additive (copper electrodeposition) and subtractive (electrochemical faceting) roughening and structure and performance of those materials is evaluated by material investigation and product analysis in a alkaline membrane electrolizer, demonstrating the possibility of driving the selectivity towards hydrocarbons or formate depending on the type of electrochemical roughening treatment applied. It was observed that the electrochemical faceting on copper drove the selectivity towards methane while increasing the total faradaic efficiency compared to plain polycrystalline copper surface. The electrodeposited copper sample maintained almost the same selectivity of the plain copper, instead, but with higher total faradaic efficiency.
FD:P01 Investigating the Effect of the Hydrophobic Block Structure on Durability of Ion Exchange Membranes for Electrochemical Applications
JANG YONG LEE, Korea Research Institute of Chemical Technology, Daejeon, South Korea
Recently, the most commonly used membrane in battery application fields, such as fuel cell and redox flow bttery, is ion exchange membrane, especially, cation exchange membrane. The state-of-the-art perfluorosulfonic acid polymer, Nation®, has limitations for commercial use because of high cost. As the most typical approach to overcome the limitations of Nafion IEMs, hydrocarbon-based alternative ionomers have attracted attention. However, low oxidative stability is regarded as an obstacle to restrict commercial use of hydrocarbon-based ionomer membranes. Typically, possible degradation mechanisms under oxidative attack are main chain scission and sulfonic acid group detachment. Especially, hydrophilic blocks or hydrophilic moieties have been considered as the main reason on degradation of hydrocarbon-based ionomers, while the significance of hydrophobic moiety has been neglected in ionomers. Herein, four kind of poly(p-phenylene)s-based cation conducting polymeric membrane materials with different hydrophobic block structures were successfully synthesized by Ni(0)-catalyzed coupling polymerization for investigating the effect of the hydrophobic block structure on durability of membrane in electrochemical applications
FD:P02 Durable Supercapacitor Based on Nanoscale Confinement of Manganese Oxide Nanoparticles in Hollow Carbon Nanostructures
C. HERREROS-LUCAS, A.N. KHLOBYSTOV, M.C. GIMENEZ-LOPEZ, School of Chemistry University of Nottingham, UK; M.W. FAY, Nanoscale and Microscale Research Centre, University of Nottingham, UK
A significant effort is currently being made in developing environmentally friendly functional nanomaterials which offer both an outstanding performance and a long-term stability. Among all the candidates, manganese compounds have received a lot of attention not only due to their relatively high abundance, low cost, environmental benignity, and structural versatility but also because their excellent performance in the field of electrochemical energy storage and conversion. However, their wide application as electrode material is mainly hindered by the leaching of manganese cations which drastically affects the long-term stability. In comparison to previous methods, where the manganese oxide nanoparticles were chemically modified (i. e. cation substitution or coating), here, we investigate a simpler approach to mitigate their dissolution by the encapsulation of the nanoparticles inside of hollow carbon nanofibers. The produced (metal oxide)-carbon hybrid shows an outstanding electrochemical stability, with a specific capacitance increase over 13,000 cycles, which is not related to a chemical changes in structure or composition. This newly discovered phenomenon contributes to the rational design of metal-carbon hybrid nanostructures for electrochemical applications.
FE:P03 Synthesis of Composites in the Y-doped ABO3 Perovskite Type Structure - V2O5 Systems by Impregnation Method
A. LACZ, E. DROZDZ, AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Krakow, Poland
In the field of ceramic conductors based on the ABO3 perovskite structure materials a new trend is clearly seen - the synthesis of composites with the ABO3 as the main phase, while the second phase is located in the intergranular voids of the perovskite material. Composites in two systems Y-doped SrTiO3 - V2O5 and Y-doped BaCeO3 - V2O5 were synthesised by impregnation method. Yttrium doped strontium titanate and yttrium doped barium cerate were synthesised by sol-gel and solid state reaction method, respectively. Sintered ABO3-based materials with the define porosity were impregnated with non-aqueous solution of vanadyl acetylacetonate (the V2O5 precursor) in the multistep process. The proper thermal treatment resulted with formation of the two phase materials: Y-doped ABO3 (SrTiO3 or BaCeO3) and vanadium oxide (V2O5). The structure and microstructure of synthesised composites were analysed, together with the characterisation of their electrical properties, mainly the type and value of conductivity and chemical stability toward CO2 and water vapour.
Acknowledgements: This work was financially supported by the Polish National Science Centre, Grant No. 2014/14/E/ST5/00763.
FE:P04 Synthesis and Properties of Porous Ni/SrTiO3/YSZ Composites
E. DROZDZ, A. LACZ, AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Krakow, Poland
The idea of application of composites: yttria-stabilized zirconia (YSZ) and yttrium/chromium doped strontium titanate (Y-doped SrTiO3 and Cr-doped SrTiO3) systems as an alternative for nickel cermet in SOFC anode material is considered. The doped strontium titanate is regarded as a potential mixed ionic-electronic conductor, however, some studies indicate that the ionic conductivity of this material is insufficient, hence the proposal of combination doped- SrTiO3 with a typical ionic conductor such as yttria-stabilized zirconia. A series of materials Y-SrTiO3/YSZ and Cr-SrTiO3/YSZ were synthesized by sol-gel method. Nickel was introduced into the obtained materials by impregnation with nickel precursor solution and proper thermal treatment. As prepared materials were characterized by means of X-ray diffraction (phase composition) and scanning electron microscopy methods (microstructure). Moreover, electrical properties were examined by electrochemical impedance spectroscopy method. Additionally, the possibility of participation in oxidation - reduction processes was analysed by temperature-programed reduction and temperature-programed oxidation measurements.
Acknowledgements: This work was financially supported by the Polish National Science Centre, Grant No. 2014/14/E/ST5/0076
FE:P08 Carbon Monoxide Poisoning Effect on Fuel Cell Performance with Consideration of Cathode Liquid Flooding
KEN-MING YIN, W.-K. XIA, Y.-L. LAI, Chemical Engineering Department, Yuan Ze University, Taoyuan, Taiwan
Carbon monoxide poisoning effect is very important when considering the application of fuel cells in powering vehicles. For the on-board generation of hydrogen, trace amounts of carbon monoxide from reformer cause deactivation of anode catalyst, rendering the malfunction of the cell. Previous mathematical models on the cell performance in the presence of CO provided insights on the poisoning mechanism of cell performance. However, few models discussed the mass transfer limitation due to liquid water flooding in the cathode diffusion layer. Experimental data reveal that cell performance cannot be assessed properly without consideration of transport phenomena in the cathode. In the present work, we propose a semi-analytical model that can evaluate the cell operation in the presence of CO at anode, with consideration of cathode flooding effect.
FF:P01 Optimization in Basic Thermoelectric Properties of n-type Mg2Si and Improvement in Elemental Durability Issues for Industrialization
TSUTOMU IIDA, T. KODAMA, M. TOKUMURA, H. HAMBA, T. MANBA, R. HATANAKA, D. SHIOJIRI, K. NISHIO, A. YASUMORI, Y. KOGO, Department of Materials Science and Technology, Tokyo University of Science, Tokyo, Japan
Intermetallic silicide of magnesium silicide (Mg2Si) is a promising candidate for practical thermoelectric (TE) power generation, because it has several promising features, such as the abundance of its constituent elements, its non-toxicity, and the facts that it is light weight and has the capability of generating power. These features have motivated the development of Mg2Si for several years now. To further increase the TE capability of Mg2Si for the realization of a practical TE generator, improved power factor and figure-of-merit of ZT value are inevitable. Here, we report the updated TE properties, that are, the highest power factor and ZT value were ~3.5x10-3 W/mK2 at ~800 K, and >1.2 at ~850 K, respectively, resulting in an expected power density of ~3.7 W/cm2 at 850K/373K temperature condition, for co-doped Mg2Si with Sb and Zn. Impurity doping in Mg2Si is an effective approach to stabilize thermal durability of Mg2Si and has already obtained enduring surface condition for ~5,000 hrs at 600 °C in air condition. To realize long‑lasting surface durability of Mg2Si TE chip, we have produced several passivation coats on Mg2Si that can help us minimize oxidative degradation. In this report, we also describe the successful surface endurance of Mg2Si with industrial examples.
FF:P03 Nanostructured Ag2Te/PEDOT:PSS Hybrid Material for High Performance Thermoelectrics
M. RAJA THULASIMANI1,2,3, K.A. MAZZIO1,2, B. RYLL4, D. KOJDA4, K. HABICHT4,5, S. RAOUX1,2,3, 1Institut für Nanospektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany; 2Energy Materials In-Situ Laboratory, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany; 3Institut für Physik, Humboldt Universität zu Berlin, Berlin, Germany; 4Department Methods for Characterization of Transport Phenomena in Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany; 5Institut für Physik und Astronomie, Universität Potsdam, Potsdam, Germany
Thermoelectric materials exhibit the Seebeck effect where a temperature gradient is directly converted into an electrical potential due to the motion of the charge carriers.These materials are characterized by the figure of merit ZT= S2σT/κ, where S-Seebeck coefficient,σ-electrical conductivity,κ-thermal conductivity,and T-temperature. Nanostructuring is one route that can be used to lower the thermal conductivity as a result of nanoscale interfaces inducing phonon scattering.1Hybrid materials consisting of nanowires and polymers can enhance the electrical conductivity and the Seebeck coefficient,while retaining a low thermal conductivity.1We are pursuing a solution based synthesis of nanostructured hybrid materials consisting of PEDOT:PSS and Ag2Te due to their low cost,scalable,and simple syntheses.In our case,Te nanowires in a PEDOT:PSS matrix are first synthesized,which we then use as templates to form Ag2-xTe/PEDOT:PSS.By controlling the Ag2-xTe stoichiometry we demonstrate a transition from p to n-type in these materials.Along with the electronic properties, the stoichiometry also influences the morphology.We examine the changes in stoichiometry and morphology using XRD, XPS, TGA, TEM, and Raman,and relate these results to the thermoelectric performance.
FG:P02 The Effect of Zn and Ni Substitution on Magnetic and Microwave Absorbing Properties of Co2W Hexagonal Ferrites
HAN-SHIN CHO, TIAN LIU, SUNG-SOO KIM, Department of Advanced Materials Engineering, Chungbuk National University, Cheongju, South Korea
Magnetic (static, high-frequency) and microwave absorbing properties of Zn- or Ni-substituted Co2W hexagonal ferrites are investigated for the application to commercial Drone and Wireless LAN operated at the frequency of 5.8 GHz. The powders of composition (BaCo2-xMexFe16O27 (Me=Zn, Ni)) are prepared by calcining at 1250 ºC, where the substitution ratio x was varied from 0.0 to 1.5. With the calcined powders, the composite specimens are prepared using the silicon rubber as a matrix material. Vibrating sample magnetometer measurement indicates that the coercive force of the composite specimens of the Co2W hexagonal ferrite powders increases rapidly with Ni substitution, which is attributed to the increase of crystal anisotropy field by changing the easy-axis of magnetization from basal plane to c-axis. The complex permeability spectrum shows the increase of resonance frequency with Ni substitution above 18 GHz. On the contrary, the composite specimens of Zn-substituted Co2W hexagonal ferrite powders exhibit the increase in saturation magnetization and the decrease in coercive force. As a result, the ferromagnetic resonance occurs in the frequency range below 6 GHz and the resonance frequency decreases with increasing Zn substitution. The result is attributed to the decrease of crystal anisotropy field in the basal plane. The specimens with Zn substitution show the superior microwave absorbing properties in C-band. For the specimen of x = 1.0, reflection loss decreases to as low as less than -30 dB at 5.8 GHz with a matching thickness of 4.0 mm. The Zn substituted Co2W hexagonal ferrites can be suggested as a good absorbing material for the electromagnetic radiation in the frequency of Drone and Wireless LAN frequency of C-band.
FG:P05 Magnetic and Transport Properties of Superelastic Fe43.5Mn34Al15Ni7.5 Heusler Alloys
V. KHOVAYLO1, M. SEREDINA1, M. LYANGE1, A. BOGACH2, R. CHATTERJEE3, T. OMORI4, R. KAINUMA4, 1National University of Science and Technology “MISiS”, Moscow, Russia; 2Prokhorov General Physics Institute, Moscow, Russia; 3Indian Institute of Technology Delhi, New Delhi, India; 4Department of Materials Science, Graduate School of Engineering, Tohoku University, Sendai, Japan
FeMnAl-based ferrous alloys demonstrate well-defined superelastic properties in a wide temperature range due to stress-induced martesnitic transformation . The uniqueness of these materials is a weak dependence of the superelastic stress on temperature which is thought to originate from a small transformation entropy change. Besides superelastic properties, it can be of considerable fundamental and practical interest to study basic physical properties of these materials. Here we report on magnetic and transport properties of polycrystalline Fe43.5Mn34Al15Ni7.5 (at.%) alloys prepared by induction melting. Further details on the samples preparation can be found in Ref. . Measurement of magnetic hysteresis loop revealed that in a temperature interval from 350 K down to 20 K Fe43.5Mn34Al15Ni7.5 demonstrated behavior typical for soft magnetic materials with vanishingly small coercivity of about 5 Oe. Temperature dependence of electrical resistivity is typical for semiconductors in a low-temperature region (at T < 300 K). A crossover from the semiconducting-like to a metallic-like behavior of the resistivity is observed at T ~ 370 K. Origin of these peculiarity in the transport properties will be discussed in presentation.
 T. Omori, et al. Science 333 (2011) 68
FG:P06 FRIMAG Project: Development of a Prototype of Magnetocaloric Refrigerator
S. FABBRICI, MIST E-R scrl, Bologna, Italy; C. BENNATI, F. ALBERTINI, IMEM-CNR, Parma, Italy; M. SOLZI, SMFI Department, University of Parma, Parma, Italy; F. Melino, DIN - Alma Mater Studiorum University of Bologna, Bologna, Italy; A. FARINA, Industrial Engineering Department, University of Parma, Parma, Italy; V. MUSSI, MUSP Consortium, Piacenza, Italy; M. ARDOINO, Democenter-Sipe, Modena, Italy; L. FERRARA, SPIN Applicazioni Magnetiche srl, Piacenza, Italy; E. FORLIN, MBN Nanomaterialia S.p.A., Vascon di Carbonera (TV), Italy; F. POLETTO, Jonix Srl, Bologna, Italy
Magnetic refrigeration is an upcoming cooling technology that replaces conventional refrigerant gases with safer, recyclable magnetic materials and fluids. It has the potential to improve energy efficiency, it is safer, quieter and its power output can be scaled easily. The core of the technology is the magnetocaloric material, which changes temperature by the application and removal of a magnetic field, the latter being efficiently generated by permanent magnets. The FRIMAG project (2016-18) is a research initiative supported by the Emilia Romagna region aimed at studying magnetic refrigeration and assessing its potentialities within the regional industrial system: a team of laboratories with expertise on novel materials, advanced simulations and thermal machines, supported by regional industries, will develop a prototype of refrigerator. The project focuses on three main topics: (i) Development and scale up of materials with high and reversible magnetocaloric effect alternative to Gadolinium, the current benchmark material. (ii) Utilizing advanced simulation methods to efficiently design the solid-fluid heat transfer mechanisms and the magnetic field source. (iii) Realization of the prototype: assessment of efficiency, costs and performance will define the application fields.
FH:P01 Synthesis and Characterization of Regenerable Fe3O4@TiO2-Noble Metal Photocatalyst Nanoparicles
KYEOUNG-MI SONG, JIN-SEUNG JUNG, Department of Chemistry, Gangneung-Wonju National University, Gangneung, Gangwondo, South Korea
Dyes and harmful organic pollutants contained in industrial and domestic wastewater spilled into the natural environment without filtration cause great damage to ecosystem and adversely affect peoples’ health. In order to solve these environmental and human health problems, we synthesized core-shell type nanocomposites using Fe3O4 magnetic nanoparticles and photocatalyst TiO2. The photocatalytic nanocompounds were synthesized to exhibit better photocatalytic activity through coated carbon layer and metal(Ag,Au) nanoparticles on surface. The prepared photocatalytic nanocompounds were photolyzed with the azo and the organic pollutants in aqueous solution. In addition, in order to check possibility of reusing the photocatalytic nanocompounds, it was separated and recovered in aqueous solution by an external magnetic field after photodecomposition of Fe3O4 magnetic nanoparticles. As a result, improvement on electron transfer and energy level difference occurred due to coated carbon layer on surface and availability of photoactivity through the visible light caused by LSPR of deposited noble metal nanoparticles on surface.
FH:P02 Optimization of Tungsten Anodization in the Presence of H2O2 to Obtain Nanostructured WO3 Photoanodes
R.M. FERNÁNDEZ-DOMENE, R. SÁNCHEZ-TOVAR, B. LUCAS-GRANADOS, J. GARCÍA-ANTÓN, Ingeniería Electroquímica y Corrosión (IEC), Departamento de Ingeniería Química y Nuclear, Universitat Politècnica de València, Spain
Tungsten trioxide (WO3) is an n-type semiconductor oxide which has been employed in technologically advanced fields, such as photoelectrochemistry. In this work, the rich and complex chemistry of tungsten has been employed to fabricate WO3 photoanodes in nanostructured form by simple anodization in acidic electrolytes containing very low concentrations of H2O2 as complexing agent (0.05 M). The aim of this study is to optimize some parameters in the anodization process (rotation velocity using a RDE, temperature, etc.) for photoelectrochemical applications. In general, very small nanoplatelets or nanosheets were formed on the tungsten surface, which aggregated forming “cones”. Electrolyte temperature and rotation velocity have an influence on the morphology of these nanostructures, which in turn will affect the photoelectrochemical performance of these photoanodes.
Acknowledgments The authors thank for the financial support granted by Ministerio de Economía y Competitividad (Project Code: CTQ2016-79203-R), and for the co-finance by the European Social Fund.
FH:P03 Plastics and Photocatalysis: A Winner Combination for the Prevention of the Incoming of Plastic Wastes to the Environment
M.C. ARIZA-TARAZONA1, A. ALVAREZ-MÉNDEZ1, J.J. RUIZ-VALDÉS1, C. MUGONI2, V. BARBIERI2, C. SILIGARDI2, E.I. CEDILLO-GONZÁLEZ1, 1Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, San Nicolás de los Garza, N.L., Mexico; 2Universitá degli Studi di Modena e Reggio Emilia, Dipartimento di Ingegneria "Enzo Ferrari", Modena, Italy
An average consumer uses different plastics products in his daily life. Most of them don't degrade naturally, so when discarded they accumulate in landfills or the environment. Small items, i.e. microplastics (<5mm), have the potential to be transferred between trophic levels and thus be dangerous to animals and humans. Photocatalysis constitutes an excellent option for the degradation of plastics. Here, photocatalytic degradation of micro-expanded polystyrene (micro-EPS) was studied using a ceramic derived N-TiO2 (particle size ≥ 40 micron) in solid media varying temperature, humidity and pollutant and photocatalyst concentration. Although sol-gel derived nano-semiconductors are usually employed for pollutant degradation, here we demonstrated that a ceramic-derived micro-N-TiO2 is suitable for degradation of plastic. To enhance degradation, composites were used to increase the interaction between the plastic and N-TiO2, leading to degradation of 10% in 20 h of irradiation vs. 50-120 h previously reported in the literature. It was found that the experimental conditions influence the efficiency of the process, changing the percentage of micro-EPS degradation and kinetics. It was concluded that micro-N-TiO2 photocatalysis can be effectively used for the degradation of micro-EPS.
FI:P02 Photoluminescence of Fullerene C60 Thin Film in Plasmon Coupled “Monolayer of Au Nanoparticles – C60 Film – Al Film” Nanostructure
O. YESHCHENKO, V.V. KOZACHENKO, N.I. BEREZOVSKA, Y.F. LIAKHOV, Physics Dept., Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
The optical properties of plasmon coupled Au nanoparticles monolayer – C60 film – Al film nanostructure were studied in dependence of the fullerene film thickness varied in the range of 10 – 95 nm. Effects of the fullerene spacer thickness on plasmonic coupling of Au nanoparticles (NPs) with Al film were analyzed basing on the dependences of the intensity, wavelength and width of surface plasmon resonance (SPR) extinction peak of Au NPs and the intensity of C60 photoluminescence (PL) on the fullerene film thickness. The red shift, non-monotonic dependences with maxima of the intensity and width of SPR in Au NPs at the decrease of the spacer thickness were observed and considered as the result of thickness dependent plasmon coupling between Au NPs monolayer and Al film. The non-monotonic dependence with minimum of the plasmonic enhancement factor of the photoluminescence of C60 film on its thickness was also observed. The extrema of the thickness dependences of SPR extinction peak intensity and width and fullerene PL intensity occur at the same thickness value of 50 nm that allows to assume the same physical mechanism of such non-monotonic dependences. We assume that such mechanism is the excitation of the propagating SP-polaritons in Al film by the plasmonic near field waves.
FJ:P01 Microstructure and Electric Properties of Transparent Indium Oxide Thin Films Prepared by RF Mangetron Sputtering
TIAN LIU, YONG-SOO JUN, MIN-SUNG KIM, SUNG-SOO KIM, Department of Advanced Materials Engineering, Chungbuk National University, Cheongju, South Korea
Transparent conductive films (indium oxide (In2O3)) are deposited on glass substrate by RF magnetron sputtering and their electrical properties were investigated in relation with microstructure. Sputtering deposition was carried out with variations of normalized substrate temperature (Ts/Tm where Tm is melting temperature) and argon partial pressure (PAr). The growing morphology is greatly influenced by substrate temperature. At very low substrate temperature (Ts/Tm < 0.1), the columnar grains with voided grain boundary are observed in the In2O3 films. The results are attributed to the low surface mobility and atomic shadowing effect. With increase of substrate temperature, tight grain boundaries are formed between the growing columnar grains. At high temperature (0.3 < Ts/Tm < 0.5), the grain surface is faceted resulting from high surface mobility of sputtered atoms, and development of preferred orientation with grain growth is promoted. The growing morphology is also dependent on argon partial pressure. At low PAr deposition, the inclined fibrous grain oriented to the target direction and smooth surface structure was developed. As the PAr increases, a dome-shaped surface structure and columnar grains normal to the substrate are developed due to the scattering effect of sputtered atoms. The growing morphology with substrate temperature and argon pressure coincides well with the Thornton's Structure Zone Model (SZM). Depending on the growing morphology, the electrical resistivity is sensitive to sputtering conditions. The lowest electrical resistivity (2.1×10-2 Ωcm) is observed in the In2O3 films with tight grain boundaries and faceted grains, which corresponds to Zone II region of SZM. The observed relationship between the grain structure and electrical properties can be applied to other types of transparent conducting films.
FJ:P03 Mössbauer Study on the Substitution of Tin Oxide for Iron Oxide in Conductive Barium Iron Vanadate Glass
YUKI FUJITA1, H. MIYAMOTO1, T. IZUMI1, S. MASUDA1, S. KUBUKI2, T. NISHIDA1, N. OKA1, 1Kindai University, Iizuka, Fukuoka, Japan; 2Tokyo Metropolitan University, Hachi-Oji, Tokyo, Japan
Barium iron vanadate glass, e.g., 20BaO·10Fe2O3·70V2O5, and its analogs show high electrical conductivity (σ) amounting to the order of 10-1 Scm-1 [1,2]. This is brought about by isothermal annealing of only several ten minutes at a given temperature higher than its glass transition temperature or crystallization temperature. Substitution of CuI(3d10), ZnII(3d10) and CuII(3d9) for FeIII(3d5) caused an additional increase in the σ value . We investigated substitutional effect of SnIV(4d10) and SnII(5s2) for FeIII(3d5) on the local structure and σ. After annealing, σ of 20BaO·5Fe2O3·5SnO·70V2O5 glass was lower than that of SnO-free vanadate glass. RT-Mössbauer spectrum revealed that quadrupole splitting (Δ) of 0.66 mm·s^-1 obtained for FeIII in 5 mol%-SnO containing glass was larger than that of SnO-free vanadate glass: 0.57 mm·s^-1. These results reflect decreased local symmetry or increased distortion of FeO4 and VO4 tetrahedra. It seems that that the carrier mobility was not improved as expected.
1) K. Fukuda, A. Ikeda and T. Nishida, Solid State Phenom., 90/91, 215-220 (2003). 2) T. Nishida, Y. Izutsu, M. Fujimura, K. Osouda, Y. Otsuka, S. Kubuki and N. Oka, Pure and Appl. Chem. 89(4), 419-428 (2017); DOI 10.1515/pac-2016-0916.
FJ:P04 Films of Transparent Conductive Oxides for Nitric Oxide Detection at Low Level
M.V. CHUPRIN, O.M. IVANOVA, S.A. KRUTOVERTSEV, L.S. KRUTOVERTSEVA, A.E. TARASOVA, CJSC “Ecological sensors and systems”, Zelenograd, Moscow, Russia
Electrical properties of transparent conductive oxides have value in application for gas analysis sensors. There are a set of interrelated processes in the sensitive layer of the sensor when exposed in the gaseous medium: electronic processes, surface and bulk diffusion of adsorbed particles, the transfer of charge carriers between the grains of polycrystalline samples. Dopants and forming methods of sensitive layers are significant on reaction to different gas component. We investigated electrical signal changes of oxide layers to nitric oxide (NO) microconcentrations. Exhaled NO is widely accepted as a non-invasive marker of airway inflammation. A method of nonoxidizing detection of NO in breath can be used as an alternative to the expensive chemiluminescence technique. The comprehensive characteristics of sensors developed on the basis of ZnO and SnO2 doped with CdO and La2O3 were investigated. The sensitive element was an alumina substrate with dimensions of 2 x 0.5 x 0.2 mm, the one its side is covered with a gas sensitive film, another side has a film heater was made of platinum paste. Thick film technique and vacuum evaporation were used for deposition of sensitive films. A temperature impulse mode effect on a sensitive layer was used for detection of NO. Sensors based on ZnO had high repeatability and resistance stability. Sensors of SnO2/CdO showed high sensitivity to NO at 5 ppb level in air, response time of sensors didn’t exceed 10 seconds.
FK:P02 Corrosion Behaviour and Microstructural Stability of Alumina-forming Austenitic Model Alloys Exposed to Oxygen-containing Molten Lead
HAO SHI, A. JIANU, A. WEISENBURGER, S. MIRAN, A. HEINZEL, R. FETZER, L. FABIAN, G. MUELLER, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
It is well known that molten lead and lead-based alloys are under consideration as working fluids for energy-related applications, such as advanced nuclear reactors, concentrated solar power and hydrogen production. However, the issue of the compatibility with structural steels, in terms of corrosion and mechanical resistance, causes considerable concerns in the case of HLMs. Alumina-forming austenitic alloys, exhibiting high-temperature creep strength and oxidation resistance in dry and humid air, are a relatively new class of stainless steels . The results of a systematic study concerning the corrosion behaviour and microstructural stability of alumina-forming austenitic steels, during their exposure to oxygen-containing molten lead, are presented in this communication. Model alloys of FeCrAlNi system, prepared by arc melting under argon atmosphere, were designed in order to form protective alumina scale and in the same time to preserve the austenite structure. Samples were exposed in stagnant molten lead with 10-6 wt.% oxygen, at 500 - 600°C temperature range for up to 1000h. The minimum Al concentration, required to form a protective alumina scale, as well as the stability of austenite phase are discussed and corroborated with the concentration of Cr, Ni.
FK:P03 Structural State Features of the Base Metal after Recovery Annealing and Long-term Operation within VVER-440 RPV
E.A. KULESHOVA, A.S. FROLOV, D.A. MALTSEV, G.M. ZHUCHKOV, S.A. BUBYAKIN, D.Yu. ERAK, D.A. ZHURKO, S.V. FEDOTOVA, NRC KI, Moscow, Russia
This paper presents the results of studies of the of VVER-440 reactor pressure vessel (RPV) steel cut from the operating reactor (templates) and also from the decommissioned reactor (trepanes). Both RPVs are manufactured from 15KhNMFA steel of similar composition and were under operation after the last standard recovery annealing up to a close fast neuron fluence. However, the RPV of decommissioned reactor was twice subjected to recovery annealing, in contrast to the operating reactor RPV that was annealed once. The templates and trepans were cut both from the sites that underwent recovery annealing and from the areas that were in the temperature gradient during annealing. The aim of this work was to study the effect of recovery re-annealing on the accumulation rate of radiation defects, radiation-induced precipitates, and also on the tendency to grain-boundary phosphorus segregations formation. At this the densities, sizes and compositions of radiation-induced precipitates were determined using the methods of transmission and scanning electron microscopy and atom probe tomography. The level of grain-boundary segregations was estimated by Auger electron spectroscopy as well as assessed by fractographic analysis of specimens after impact tests and fracture toughness.
FK:P04 Structural Features of Hydride Phase Formation in E110 Zr-alloy under the Influence of Various Factors
B.A. GUROVICH, E.A. KULESHOVA, A.S. FROLOV, D.A. MALTSEV, O.O. ZABUSOV, D.V. SAFONOV, E.V. KRIKUN, A.S. BRAGIN, NRC KI, Moscow, Russia
In fuel elements manufactured from E110 Zr-based alloy, hydride phase formation is observed under nuclear power plant operation, which leads to the mechanical characteristics degradation of the zirconium fuel rod claddings. The source of hydrogen is primarily the gas liberated by interaction with the coolant. Additional factors affecting the process of hydrogen absorption are the temperature and stresses in the cladding. After reactor operation, products from zirconium placed for long-term storage contain hydrogen absorbed during operation (0.003-0.05 wt %), defects (cracks) arising during operation, and also stresses caused by various causes. Thus, all the factors responsible for the hydride phase formation and realization of delayed hydride cracking are present, since this phases reduce the material ability to plastic deformation and reduce its fracture toughness (stress intensity factor). The highest embrittlement is caused by lamellar phases, oriented perpendicular to the direction of tensile stress action. In the case of pipes under pressure, first of all, radially oriented hydrides are dangerous. In this work, metallographic and microstructural studies using transmission and scanning electron microscopy of VVER-1000 reactor fuel rod samples in initial state, after hydrogenation up to 100 and 200 ppm, and also after different isothermal exposures under axial loads up to 60 MPa were carried out. The dependence of the hydride reorientation coefficient on the applied axial stresses and isothermal exposure duration is shown.
FM:P05 On the Resistive Switching Properties of Random Access Memory Based on Yttria-stabilized Zirconia
S.L. CHAO, J.S. CHERNG, Department of Materials Engineering, Ming Chi University of Technology, Taipei, Taiwan
A series of yttria-stabilized-zirconia (YSZ)-based resistive random access memory (RRAM) are manufactured and studied systemically. The RRAM consists of a Mo bottom electrode (300 nm), a YSZ dielectric film (30 nm) and a Ti top electrode (300 nm). The electrodes are made by DC magnetron sputtering, while a transition-mode reactive sputtering corresponding to 20% of target poisoning is employed to produce the YSZ film with a microstructure having ultrafine crystallites embedded in an amorphous matrix. Such an YSZ film undergoes an abnormal grain growth upon annealing at 400oC for 2 hours. The grain boundary thus serves as the main path of the oxygen vacancies, which in turn drastically affects the resistive switching properties of YSZ-based RRAM.
FM:P07 Self-assembly of Metal@Al2O3 Core-shell Nanoparticles and Nonvolatile Memory Properties
JONG-HWAN YOON, Department of Physics, Kangwon National University, Chuncheon, South Korea
Recent nonvolatile memory devices (NVM) are demanded to have smaller sizes, faster operating speeds and larger storage capacities. One way to realize such devices is to use transistors with floating gates composed of metal nanoparticles based on low-k/high-k dielectric stacked tunnel barriers, such as an SiO2/Al2O3 stacked layer. Here, we report a simple method for fabricating metal@Al2O3 core-shell nanoparticle layer embedded in silicon dioxide (SiO2), which simultaneously realizes both a metal nanoparticle floating gate and a low-k/high-k dielectric stacked tunnel barrier. The fabrication of metal@Al2O3 core-shell nanoparticles was achieved by thermally annealing a sandwich structure consisting of a metal layer sandwiched between two silicon-rich oxide layers within SiO2. The metal@Al2O3 core-shell nanoparticle floating gates exhibit characteristic memory properties, including a large memory window and stable data retention, suitable for NVM applications. These results demonstrate that the formation of a metal@Al2O3 core-shell nanoparticle layer within SiO2 simply provides a simple route for fabricating metallic nanoparticle floating gate memory structures with a low-k/high-k dielectrics stacked tunneling barrier.
FN:P01 Synthesis and Characterization of Stable and Ordered-packing High Order Acenes
QING WANG, N.L. ARUN, C.Y. CHI, National University of Singapore, Singapore
Acenes are linearly fused one dimensional polybenzenoids and acenes longer than pentacene are collectively called as high order acenes, such as hexacene, heptacene etc.. Recent applications of acenes as active materials in organic electronic applications escalated interest. Such studies, however, has been limited to easily accessible shorter homologs such as tetracene and pentacene. Its most staggering aspect is the rapid evolution of physicochemical properties of high order acenes. But it was concluded that high order acenes are too reactive to be synthesized. Their poor solubility also exacerbated the possibility of these molecules to be studied in detail. In this work, we discuss a new strategy to synthesize stable and soluble high order acenes, CP-Hex and CP-Hep with ordered molecular packing. The fundamental concept is to functionalize these acenes with two aryl groups fused on both side along the peri-positions. The target compounds have been synthesized now and studies of their other physicochemical properties are in progress. The protocol in our work holds promise to synthesize stable high order oligoacenes and heteroacenes, and it will open up a whole new frontier in the field of organic materials.
FN:P02 Functional Nanocomposites with Graphene-DNA Hybrid Complexes: Fabrication and Surface Properties under UV Irradiation
E. TOTO, M.G. SANTONICOLA, Dept. of Chemical Materials and Environ-mental Engineering, Sapienza University of Rome, Rome, Italy; S. LAURENZI, Dept. of Astronautic Electrical and Energy Engineering, Sapienza University of Rome, Rome, Italy
Graphene-based nanocomposites with multifunctional properties are used as sensing materials in various environments. The integration of the graphene sensing elements into the polymer matrix is not a trivial task, as the overall sensing properties of the material are highly affected by the amount and homogeneity of the filler dispersion. Here we investigate the fabrication process of functional nanocomposite films based on graphene-DNA hybrid complexes embedded in a flexible polydimethylsiloxane (PDMS) matrix. UV-sensitive nanocomposites were realized exploiting the highly conductive nature of graphene nanoplatelets (GNP) combined with the chemical sensitivity of DNA strands to UV radiation. In addition, the DNA molecules are efficient solubilizing agents for the GNPs and, at the same time, enhance the curing process of the GNP-loaded PDMS matrix. Surface properties of the nanocomposite films in terms of morphology, electrical conductivity and wettability were investigated before and after UV-C exposure. Results give information on the potential applications of PDMS/GNP-DNA nanocomposites as biocompatible and sensitive materials for monitoring in extreme environments characterized by high levels of biologically-damaging UV-C radiation, such as the space environment.
FN:P06 A Microfabricated Sensor for Detecting Biochemical Markers of Bone Formation
S. SIRIVISOOT, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
Osteocalcin (bone gla-protein) is secreted by osteoblasts and is a biochemical marker of bone formation. While it can be detected using biochemical assays, detection is highly problematic due to long testing times and small amounts of protein present during early bone formation. We microfabricated an implantable device-on-chip for the real-time detection of osteocalcin using various techniques, including three-dimensional printed mask fabrication, counter/reference/working electrode fabrication, and chamber molding. Due to its electrochemical properties, unique structure, and biocompatibility, graphene oxide was applied to the working electrode of the microfabricated sensor to increase the current signal produced by osteocalcin. The redox signal of osteocalcin on the microfabricated chip was achieved by cyclic voltammetry to determine the protein concentration from peak currents. The chip can also be used to detect other non-collagenous proteins, such as osteopontin and osteonectin, which cannot be detected using current bioassays due to their very low concentrations. This implantable device can be used to detect early bone formation on-site in real time under various pathologic conditions, such as osteomyelitis, osteoporosis, or heavy fractures.
FO:P01 Superconducting Properties of a new Oxysulfate Superconductor
HO KEUN LEE, J. KIM, Department of Physics, Kangwon National University, Chuncheon, South Korea
A new thallium copper oxysulfate TlSr4Cu2(SO4)O6+z has been synthesized by using a solid-state reaction method. This new phase crystallizes in the tetragonal system and exhibits superconductivity with a Tc(zero) up to 74 K. Additional annealing treatments under various atmospheres and doping effects of aliovalent elements indicate that the pristine sample is under near optimally hole-doped state and the experimental results are discussed in connection with the room temperature thermoelectric power measurements.
FO:P03 Design and Simulation of 4-bit Random Access Memory Composed of Reciprocal Magnetic Flux Quanta
S. NARENDRAN, J. SELVAKUMAR, SRM Institute of Science and Technology, Chennai, Tamil Nadu, India
As CMOS technology will get over by 2020 and the Rise of Post Moore law technology will be seeking with low power, high-speed operation. The efficiency of high-performance computing is in high demand with both speed and energy efficiency. Reciprocal Quantum Logic (RQL) is one of the technologies which will produce high speed and zero static power dissipation. RQL has three set of basic gates: A-not-B gate, AND-OR gate, and Set-Reset. Series of reciprocal transmission lines are placed in between each gate to avoid loss of power and to achieve high speed. Many developments made on RAM using CMOS technology to achieve ultra-speed processor and devices. A 4-bit RAM cell is designed using VHDL (VHSIC Hardware Description Language) with the help of Josephson Junctions (JJ’s). VHDL is one of the Hardware description language used to develop EDA’s. Random Access Memory cell are first synthesized and then simulated using Free HDL software which provide IEEE standards 1076 2002 to adopt superconductor logic (Josephson Junction). The estimated speed of RQL based design works in range of 100GHz to 130GHz. The Josephson Junction (JJ) counts is only criteria to analyze the complexity of the ALU design. RQL based design can be used in many real-time applications like supercomputers, quantum computers, mobile phones, and other microprocessor system applications. Major drawback of reciprocal Quantum Logic is area, because of lack in proper power supply. To achieve proper power supply we need to use splitters which will occupy large area.
FP:P01 Development of Gold Nanorod-based SERS tag for Food Safety Monitoring
R. PARDEHKHORRAM1, YUANHUI ZHENG1, P. BAKTHAVATHSALAM1, R. TILLEY1, NANJU ALICE LEE2, J.J. GOODING1,3, University of New South Wales, Sydney, NSW, Australia: 1School of Chemistry, 2School of Chemical Engineering, 3ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Sydney, NSW, Australia
Foodborne pathogens have become major public health issue all over the world resulting in substantial losses in food business and whole industry. Developing rapid and sensitive method capable of detecting pathogenic microorganisms in low level has been an ever increasing need. So far, several detection techniques have been employed for food safety analysis. However, they are mostly time consuming, laborious and required special instrument, as a result developing a new assay with less complexity and detection time is still needed. Driven with this demand, we suggest antibody conjugated-gold nanorods (Au NRs) as a promising surface-enhanced Raman spectroscopy (SERS) tag for rapid and sensitive detection of pathogens. Gold nanorods are an interesting class of anisotropic nanomaterials which exhibit a strong localized electric field at theit tips making them a functional option for SERS. In this work we fabricated our SERS probe by preferentially attachment of Raman-active molecule (4-aminothiolphenol) at the Au NRs tips, then following by antibody immobilization step. Final detection will be carried out by calibrating the intensity of characteristic Raman signal from reporter molecules with the concentration of target analyte.
FP:P05 Synthesis of Nanometric TiO2 and its Application as Bionanomaterial
V. GONZALEZ-TORRES, M.R SÁNCHEZ-DÍAZ, Escuela de Ciencias de la Salud Valle de las Palmas de la Universidad Autónoma de Baja California, Tijuana, Baja California, México; M. ROSALES-AGUILAR, Facultad de Medicina y Psicología de la Universidad Autónoma de Baja California, Tijuana, Baja California México; Ma.E. VILLAFUERTE-CASTREJÓN, Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Ciudad de México, México; E. HERNÁNDEZ-GUEVARA, G.C. DÍAZ-TRUJILLO, Facultad de Ciencias Químicas e Ingeniería de la Universidad Autónoma de Baja California, Tijuana, Baja California, México
The synthesis of TiO2 nanomaterials has been of great interest in recent years. Because of its reduced particle size, these materials have better properties and extends its applications as a catalyst, solar cell components, optical lenses and biological systems, just to mention some of their predominant applications. This study presents the first results of the synthesis of nanometric TiO2 trough sol-gel technique using Ti[OCH(CH3)]4/Alcohol as a precursor agent in a molar ratio of 1.5/2. Four varieties of solvents were selected according to their chemical structure: aliphatic, alicyclic and aromatic chains. Materials were obtained using same experimental conditions. A thermic treatment up to 500°C/8 h was applied to all materials prepared. Characterization of these materials was made by X-ray diffraction, infrared spectroscopy, scanning electron, atomic force and transmission electron microscopy. Using aliphatic solvents TiO2 was in anatase form. Using aromatic solvents TiO2 was presented in a mixture of anatase and rutile. It was concluded that the best dissolvent to synthesize TiO2 nanoparticles is tert-Butyl alcohol since it forms a single crystalline form of the mineral, the particle´s structure is predominantly regular with an average size between 2.27 and 14.5 nm.
FP:P07 Isolation and Imaging of Circulating Tumor Cells
CHIUNG WEN KUO, PEILIN CHEN, Research Center for Applied Sciences, Academia Sinica, Taiwan
In this poster, we will present the recent developments in our group related to circulating tumor cells (CTCs). We will first discuss the utilization of multi-photon microscopy for monitoring CTCs in the blood stream with the help of quantum dots. CTCs are cancer cells that break away from a primary tumor or metastatic site, escape from immunosurveillance, and then circulate in the peripheral blood with the capability of forming distant metastases. The number of CTCs has been used as an indication for the progress of tumor state. However, how CTCs travel in the bloodstream and how they crossed the endothelial barrier are not known. In our group, we have utilized multi-photon microscopy to study CTCs noninvasively. Pancreatic cancer cells expressing fluorescence were subcutaneously injected to the earlobes of mice forming solid tumor. When the cancer cells break away from the tumor mass, the cancer cells in blood stream can be monitored. The number of CTCs observed in the blood vessels near the tumor mass increased to a maximum value after five week of inoculation. We also tried to identify a sub population of CTCs such as cancer stem cells (CSCs). The trajectories of CTCs and CSCs were measured and analyzed.
FP:P08 Programmable Multiple Capture/Release of Circulating Tumor Cells Using Conducting Polymers
DI-YEN CHUEH, CHIUNG WNE KUO, PEILIN CHEN, Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
In this study, we have developed a novel one-step electrospinning process to fabricate poly(ethylene oxide) (PEO)/poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) core/shell nanofiber structures with improved water resistance and good electrochemical properties. We then integrated a biotinylated poly-(L-lysine–graft–ethylene glycol) (PLL-g-PEG-biotin) coating with three-dimensional (3D) PEDOT-based nanofiber devices for dynamic control over the capture/release performance of rare circulating tumor cells (CTCs) on-chip. We have demonstrated that these nanofiber mats deposited on five-patterned indium tin oxide (ITO) finger electrodes are excellent candidates for use as functional bioelectronic interfaces for the isolation, detection, sequential collection, and enrichment of rare CTCs through electrical activation of each single electrode. This combination behaved as an ideal model system displaying a high cell-capture yield for antibody-positive cells while resisting the adhesion of antibody-negative cells. More than 90% of the target cells were captured on the 3D PEDOT-based nanofiber microfluidic device, and more than 80% of the captured target cells were subsequently released for collection.
FA:HP06 Ternary Ti-Si-C Alloy Film Formation on GaN and Contact Properties
Y. TAKAHASHI, M. ARAI, M. MAEDA, JWRI, Osaka University, Osaka, Japan
It is very important to obtain ohmic contact for electronic power devices such as compound semiconductors of GaN and SiC. In the present study, ternary Ti-Si-C alloy film was deposited on GaN substrates (n-type and p-type) by the radio frequency magnetron sputtering method. Various chemical compositions of contact film were obtained. TEM and XRD observations of microstructure were carried out. After low temperature annealing, I-V properties was improved, where I is current and V is voltage. Ohmic contact characteristics were obtained for n-type GaN. It was suggested that TiN phase made an important role to obtain an ohmic contact for n-type GaN. The I-V properties was discussed based on experimental results.
FA:HP07 Cool Plasma Sintering for Turning Printed Copper Particles into Bulk Metal
NAOKI SHIRAKAWA, Flexible Electronics Research Center, AIST, Tsukuba, Japan
Copper has been the material of choice for interconnection in main-stream electronics industry. In printed electronics, however, silver is widely used. The reason is the lack of appropriate sintering method for printed copper as copper is easily oxidized if heated in air. We have been developing sintering technology in an extremely low p(O2) environment generated with the oxygen pump. Recently we have added atmospheric-pressure plasma to the sintering, creating Cool Plasma Sintering as we call it. Traces printed with a copper nanoparticle ink (the average particle size 20 nm) as a film less than one micrometer thick were successfully converted into conductive wires at 180 degrees C. Their resistivity was as low as 2.6 microohm centimeter. Importantly, a significant grain growth occurred during the process giving rise to 300 nm-size grains and a void-free structure. The sintering is conducted at a constant temperature and there is no need to adjust process parameters according to various line widths and thicknesses in the circuit. We opened up a new route to manufacturing highly conductive copper wiring by printing.
FB:HP08 High-performance Fullerene-free Organic Solar Cells based on Small Molecule Donor and Acceptor
SORA OH, WON SUK SHIN, SANG-JIN MOON, CHANG EUN SONG, SANG KYU LEE, Korea Research Institute of Chemical Technology, Daejeon, South Korea
Recently, non-fullerene organic solar cells (OSCs) have been studied extensively to replace fullerene derivatives with electron-accepting small molecules because fullerene derivatives are expensive and gradually lead to the phase separation in blend films due to the highly different surface energy between donors and acceptors. In this study, we focused on the construction of electron-donating and –accepting small molecules that could enhance the photovoltaic performance. We expected that structural and functional similarities between the electron-donating (BDT3TR) and –accepting (O-IDTBR) materials would improve the miscibility of the blends as well as the molecular ordering. The absorption spectra, cyclic voltammetry, space charge limited current hole/electron mobility, and two-dimension grazing-incidence X-ray diffraction patterns were investigated for all materials. Bulk heterojunction devices comprising BDT3TR:O-IDTBR showed an excellent power conversion efficiency exceeding 7% and much better thermal stability than BDT3TR:PC70BM devices after ageing at 120 oC for 300 hours. Detailed synthetic scheme, optical, electrochemical, and photovoltaic properties of the oligomers will be presented.
FB:HP09 80 µm Thickness Silicon Wafer Manufacturing by Multi-wire Sawing Process
JOONSOO KIM, BOYUN JANG, SUNHO CHOI, Korea Institute of Energy Research, Daejeon, South Korea
Thin silicon wafer wire sawing is the one of the effective cost-saving methods for making low cost solar cell. The manufacturing cost of the silicon wafer can be reduced by 40% as the wafer size decreases from 180 μm to 80 μm. However, Thin silicon wafer leads to the mechanical properties during multi-wire sawing process: fracture strength, hardness and flexibility of silicon wafer. These defects affect not only cell manufacturing process but also multi-wire sawing process and the yield of multi-wire sawing on silicon ingot. This study report on the breakage and defects of 80 μm thickness silicon wafers during multi-wire sawing process using slurry.
FC:HP06 Effect of Zr and Zr7Ni10 on Hydrogenation Kinetics of Ti-V-Cr Alloys
V. DIXIT, J. HUOT, IRH, UQTR, Trois-Rivières, Québec, Canada
Hydrogen is considered to be an attractive energy carrier because of its high energy density and pollution-free nature. Among various materials, body centred cubic (BCC) solid solutions and alloys are considered to be promising hydrogen storage alloys. These alloys also have some drawback, one of them being that a heat treatment is usually required before the first hydrogenation. It has recently been found that adding doping Zr7Ni10 to BCC alloys eliminates this additional step of heating. We report here a comparative study of Zr and Zr7Ni10 as additives in BCC alloys of elemental composition Tix V70-xCr30 where x = 10, 20, 30, 40, 50. Crystal structure and morphology of the samples have been studied by the XRD and SEM analysis respectively. Hydrogenation studies were carried out by using the home-made hydrogen titration system. We found that samples with Zr7Ni10 addition have faster kinetics when Zr is added. Possible explanations of this discrepancy between doping elements and relationship of hydrogen storage with microstructure will be discussed.
FC:HP07 Tailoring Hydrogen Activation and Release by Novel Frustrated Lewis Pair Systems
H. KILDAHL, M.C. CORREIA, Maastricht Science Programme, Maastricht University, Maastricht, Netherlands
Hydrogen—with 432 kJ/mol of energy—has garnered attention as an energy carrier; however, its use as a fuel or storage medium requires easy access to this energy via activation of the H–H bond. Previous research into (phosphine-borane, amine-borane and organometallic-borane) Frustrated Lewis Pairs (FLPs) demonstrated the ability to activate hydrogen at room temperature and pressure, then release it under nominally increased temperatures. New FLP systems were tailored to study the ease of activation and release of H2 by utilizing naturally occurring or renewable amines (triazabicyclodecene, cytosine and guanine) with boranes of differing acidities (B(C6F5)3, HB(C6F5)2 and CyB(C6F5)2). FLPs were produced by stirring stoichiometric amounts of the Lewis acids and bases in toluene with 1 atm H2 for 2 hours. The resulting FLPs were characterised spectroscopically and used to determine pKa effects on the conditions required for activation and release. Heating the FLPs in C6D6 at different temperatures and for varying times allowed dehydrogenation to be followed by multinuclear NMR. FLPs with B(C6F5)3 have been shown to release hydrogen between 72–112 °C after 3 hours (triazabicyclodecene, 50%; cytosine, 37%; and guanine, 23%).
FC:HP08 Electrochemical Reforming of 1,3-propanediol for Acrylate and Hydrogen Production
M. BELLINI, J. MAHMOUDIAN, M.V. PAGLIARO, W. OBERHAUSER, M. INNOCENTI, F. VIZZA, H.A. MILLER, Istituto di Chimica dei Composti Organometallici ICCOM-CNR, Sesto Fiorentino (FI), Italy
The coproduction of acrylate and hydrogen from 1,3-propandiol is achieved by electrochemical reforming using a nanoparticle Pd on mixed Vulcan XC-72 carbon and ceria electrocatalyst (Pd/C-CeO2). Electrolysis cell parameters (potential, temperature, and flow conditions) are tuned to favor the formation of acrylate with respect to the other oxidation products (3-hydroxypropanoate and malonate). Using high cell temperature combined with a low cell voltage favors the formation of acrylate, the selectivity for which is further enhanced by flowing the 1,3-propandiol solution in single-pass mode rather than recycling through the electrolyzer. Hence, at a cell temperature of 80 degrees C and at a fixed cell potential of 400 mV using a one pass continuous flow of 1,3-propandiol, 77% of selectivity for acrylate is obtained.
FD:HP06 Comparative Electrochemical Study for MnOx Phase-variable Composites Derived from MnO2/GO Templates as for Li-rechargeable Battery Electrodes
JI YOUNG JU, SEULGI JI, SUN SOOK LEE, YONGSEON KIM, WON BIN IM, HA-KYUN JUNG, YONGKU KANG, SUNGHO CHOI, Korea Research Institute of Chemical Technology, Energy Materials Center, Daejeon, South Korea
Similar to other transition metal oxides, MnOx-based electrode materials generally suffer from cycling capacity fading, which stems from their low intrinsic electrical conductivity (10-8-10-7 S cm-1) with irreversible volume change during the repetitive Li+ migration. A representative strategy for resolving these problems is to form a hybrid composite that combines with hierarchical structured conductive materials such as 1D carbon nanotubes and 2D graphenes. In this work, the microstructure and electrochemical behavior of MnOx/rGO composites derived from a MnO2/GO template are thoroughly investigated. An as-prepared MnO2/GO mixture is gradually converted to MnO2/rGO in a reduction process and is subsequently annealed under specific conditions to form the Mn3O4/rGO composites. The overall Li+ conversion reactions are visualized and the stability of the transformed MnOx phases is evaluated using density function theory calculations. The semispherical Mn3O4 anchored composite exhibits stable electrode performances, including both the Li+ anode and the Li+-air cathode catalyst, induced by the electrochemically favorable composite with an effective large contact area between the active materials and the electronic conductive rGO.
FD:HP07 Comparative Characterization of Catalytic Properties of Ta, Nb, NixCoyOz and Carbon in Sodium-Air Batteries
E. FAKTOROVICH SIMON1, A. NATAN2, D. GOLODNITSKY1, E. PELED1, 1School of Chemistry, Tel Aviv University, Tel Aviv, Israel; 2Dept. of Physics and Electrical Engineering & Electronics, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
Sodium-air batteries have been recently studied as an alternative for lithium-air ones. In spite of lower theoretical specific energy (1980Wh kg-1 of sodium vs. 3600Wh kg-1 of lithium), abundance of sodium provides an advantage for its usage as a metal anode over lithium. Sodium-air batteries have similar reversibility problem of cathode reactions as lithium-air batteries. Applying an appropriate material as a cathode catalyst and/or supporting substrate can contribute to the formation of more reversible products on charge, increasing the cyclability and reducing ORR and OER overpotentials of the battery.
In this work, we studied ORR and OER in sodium-PEGDME500-based electrolytes, testing Ta, Nb, NixCoyOz, and Black pearls powders as the catalysts. For this purpose, the three-electrode half-cell with neat or coated-by-catalyst glassy carbon working electrode were assembled. The catalysts loading of about 40 µg/cm2 was used. It was found that in sodium PEGDME500-based electrolytes carbon materials have the highest catalytic activity for ORR and OER.
FD:HP08 Towards Fast Manufacturing of Self-standing Conductive Polymer Layers
F. AHMED, U. AIL, A. GRIMOLDI, T. EDERTH, M. BERGGREN, X. CRISPIN, Lab. of Organic Electronics, Dept. of Science and Technology, Linköping University, Sweden; K. HÅKANSSON, Wallenburg Wood Science Center, KTH Royal Institute of Technology, Stockholm, Sweden
The possibility of using papermaking machines to address low-cost, large-scale production of smart composite materials is quite attractive. Active components in composite materials that are environmentally friendly consists of forest-based products such as cellulose pulp, carbon nanofibers and conducting based polymers such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). This work is the first step towards papermaking sheets by chemical synthesis of conducting gel that consists of large PEDOT microparticles (500 µm) (flocculation of colloidal particles phenomenon) when treated with, but not limited to, sulfuric acid (H2SO4). This gel could be further mix with cellulose pulp and carbon nanofibers to yield a porous structure enabling super-fast removal of water and form conducting papers without losing PEDOT content (Fig. 1). The obtained thick electrode films (0.3 – 0.5 mm) with good electronic (100 S/cm) and ionic (0.1 S/cm) conductivities have wide range of applications from batteries, fuel cells, hydrogen peroxide production and depollution of water from toxic metal ions. This is a breakthrough in the paper manufacturing since it enables large-scale production of conducting papers and electrical storage papers.
FD:HP09 Morphological Studies of Cellulose-PEDOT:PSS Conducting Paper
D. BELAINEH1, S. MALTI2, A. GRIMOLDI1, M. MODARRESI1, L. WÅGBERG2, X. CRISPIN1, M. BERGGREN1, I. ENGQUIST1, 1Lab. of Organic Electronics, Dept. of Science and Technology, Linköping University, Norrköping, Sweden; 2Dept. of Fibre and Polymer Tech., KTH-Royal Institute of Technology, Stockholm, Sweden
Recently a robust conducting paper composed of Poly(3,4-ethylene- dioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) and nanofibrillated cellulose (NFC) has been demonstrated. NFC-PEDOT is flexible, scalable and exhibits excellent electrical and mechanical properties. The superior mixed ion-electron conductivity of this paper promises a scalable bulk manufactory of supercapacitors which otherwise would not be possible using only PEDOT:PSS. Despite the high potential of this conducting paper, an in-depth material characterization of the blend system is still missing. In this study we investigate the morphology of cellulose-PEDOT:PSS blends and we show that the PEDOT:PSS organization on the cellulose is highly dependent on the structure of the template cellulose. We use Grazing-Incidence Wide-Angle X-ray Scattering (GIWAXS) to identify stark variations in the crystallinity of the PEDOT oligomers on different cellulosic templates. We confirm these investigations by direct morphological mapping with Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM). Furthermore, we establish the direct effect of the crystallographic organization on the hole transport in PEDOT by four-point-probe conductivity measurements.
FE:HP09 Stability Evaluation of SSC Fibrous Cathode with Embedded SDC Particles for Solid Oxide Fuel Cell
SEWOOK LEE, SANGHO PARK, DONGWOOK SHIN, Division of Materials Science and Engineering, Hanyang University, Seoul, South Korea
Previous study on performance enhancement by Sm0.5Sr0.5CoO3−δ (SSC) fibrous cathode with embedded Sm0.2Ce0.8O1.9 (SDC) particles has been reported by our paper. In this work, in order to assess the feasibility and reliability of this fibrous SSC-SDC cathode as a practical cathode, we conducted the short-term stability test using a half-cell under cathodic polarization treatment to identify the degradation phenomena only at the cathode. The polarization treatment was conducted under the current density of 500 mA/cm2. The stability test was carried out at 700 °C in air under the condition of open circuit. After the measurement, the resistance associated with charge transfer and surface catalytic reaction were increased by 159 and 77 %, respectively. The reasons for this degradation can be considered common approaches of perovskites cathode materials such as grain growth and Sr-enrichment. Fortunately, the fibers maintain their original shape, porosity and interfacial adhesion to electrolyte.
FF:HP07 Energy-saving Synthesis of Bi2Te3 with Poker Deck Morphology
FEI-HUNG LIN, CHIA-JYI LIU, Dept. of Physics, National Changhua University of Education, Changhua, Taiwan
We discover a facile and scalable green route of synthesizing nanostructured Bi2Te3 with high yield at room temperature without involving any organic chemicals, capping agents, and surfactants. The Bi2Te3 shows a unique poker deck morphology. The formation mechanism involves interaction between atoms of Bi and Te, which takes place at a very slow rate and takes about 2 weeks to form Bi2Te3.
FF:HP08 Facilitated Determination of Local Composition in Inhomogeneous Quasi-binary Material Systems from Backscattered Electron Image Contrast
E. MUELLER1,2, M . YASSERI1,2, N. FARAHI2, K. KELM2, J. DE BOOR2, 1Institute of Inorganic and Analytical Chemistry, Justus Liebig University of Giessen, Giessen, Germany; 2Institute of Materials Research, German Aerospace Center (DLR), Koeln, Germany
Quantification of phases in multiphase materials and the determination of compositions in material systems with wide solubility of the components are crucial for the engineering of material properties. In the field of thermoelectrics, non-single-phase materials are of considerable interest due to the additional scattering caused by additional grain boundaries, nano-scaled inclusions or regions with different compositions, potentially improving the thermoelectric performance of the material. Size, shape, amount, and composition of side phases or domains need to be assessed and optimized to tune the material properties. SEM-EDX is state-of-the-art for such analysis. However, it suffers from a low throughput and a limited spatial resolution. In this work, a simple relation between the grey value in backscattered electron images and the respective chemical composition is demonstrated using Mg2SixSn1-x as an example system. Utilizing the grey values of the BSE images, a rapid method for phase quantification in quasi-binary material systems is introduced. Applying this method to Mg2SixSn1-x, the Si and Sn content of each individual point on the BSE images can be calculated assuming that the Mg:Si,Sn ratio remains constant according to the Mg2(Si,Sn) line phase. The introduced SEM image analysis is much faster compared to EDX mapping as it requires only two EDX point measurements for calibration. Moreover, it provides a superior spatial resolution by a factor of about two compared to EDX mapping.
FF:HP09 Influence of Ba2+ Doping on Thermoelectric Properties of BiCuSeO Fabricated by Spark Plasma Sintering
KYEONGSOON PARK, DONG HOON KIM, HO YOUNG HONG, GUN WOO JUNG, JOON WOO PI, Sejong University, Seoul, South Korea
Thermoelectric energy conversion is a highly promising technology for harvesting energy from waste and natural heat. Recent studies showed that p-type BiCuSeO oxyselenides with a layered structure have been reported as very promising thermoelectric materials due to their low thermal conductivity. In the present study, we selected Ba2+ as a dopant on the Bi3+ site in BiCuSeO to optimize the electrical transport properties of BiCuSeO, and then fabricated Bi1−xBaxCuSeO (x = 0 - 0.21) samples by spark plasma sintering. The effect of Ba2+ doping on the thermoelectric properties of BiCuSeO was studied. All the fabricated Bi1−xBaxCuSeO samples showed highly dense morphology and tetragonal BiCuSeO phase (PDF # 82-0464). Ba2+-doped samples exhibited metallic conducting behavior and the positive Seebeck coefficients that indicate p-type electrical transport behavior. The thermal conductivity decreased with increasing temperature. In this work, we showed that the dimensionless figure of merit was substantially enhanced via Ba2+ doping on the Bi3+ site.
FG:HP10 High-temperature- and High Magnetic-field-resistant, Non-volatile Memory in Ni2MnX (X: Al, Ga, In, Sn, Sb) and Soft Magnetism Fe2MnX in Heusler Nano-precipitates
A. CAKIR1, M. ACET2, 1Dept. of Metallurgical and Materials Engineering, Mugla Sitki Kcman University, Mugla, Turkey; 2Faculty of Physics, University of Duisburg-Essen, Duisburg, Germany
Recent studies on off-stoichiometric Heusler alloys have shown that Mn-rich compounds Ni50Mn50-xZx (Z : Ga, Al, Sn, Sb and In) with 0 < x < 25 decompose when temper-annealed between 650 and 750 K. In particular, the decomposition of anti-ferromagnetic tetragonal Ni50Mn45Z5 results in pinned shell-ferromagnetic core/shell Ni2MnZ nano-precipitates embedded in an anti-ferromagnetic NiMn matrix when the annealing takes place under a magnetic field of around 100 mT. The pinning is non-volatile up to 350 °C and in magnetic fields up to 20 T. While the ferromagnetic core spins of the precipitate are soft, the shell spins are strongly pinned in the direction of applied magnetic field due to the magnetic proximity interaction with the highly anisotropic NiMn matrix. Such a property makes this material interesting for non-volatile magnetic storage media. In a similar manner, the Fe-based off-stoichiometric Heusler Fe50Mn45Ga5 also decomposes into the two phases: ferromagnetic Fe2MnGa Heusler precipitates and antiferromagnetic FeMn, the latter composing the matrix. In this case, shell-pinning does not occur, and the ferromagnetism is soft due to the weak anisotropy of the FeMn matrix. They can readily align in fields as small as 2 mT. Such a soft magnetic material can be utilized in magnetic shielding applications.
FJ:HP06 Formation of Tin Sulfide Thin Films and Tin Chalcogenide Nanomaterials Using Novel Tin Single Source Precursors
BO KEUN PARK, SEONG GU KANG, TAEK-MO CHUNG, CHANG GYOUN KIM, Thin Film Materials Research Center, Korea Research Institute of Chemical Technology, Daejeon, South Korea
Tin sulfide (SnS) is one of the promising candidate for next generation solar absorber because its high absorption coefficient above 104 cm-1 and a indirect band-gap (Eg = ~1.3 eV). Chemical vapour deposition (CVD) is well known to obtain higher quality thin films with less impurities and uniform thickness. CVD methods offer several advantages such as low growth temperature, ease of controlling the impurity doping concentration, and the potential for the growth of large area thin films with high growth rate. Especially, CVD using single source precursors designed with properties including stoichiometry, volatility, stability and lower toxicity can provide an easy formation of stoichiometric pure thin films. Herein, we report the synthesis of Sn-aminothiolate single source precursors (Sn(dmampS)2 (1) and Sn (dmampS)2Se (2)) for tin chalcogenide materials or thin films, and characterization by spectroscopic methods, X-ray single crystallography, and thermogravimetric analyses (TGA). Thermal decomposition materials of the precursors are orthorhombic SnS (for 1) and hexagonal SnSSe (for 2) through XRD and EDS. Also, dense and well-faceted orthorhombic phase SnS thin films with ~ 1 μm thickness were deposited to using the precursor at 350 °C through MOCVD method.
FK:HP05 Boron Carbide- and MAX phases- based Materials for Nuclear Reactors
T. PRIKHNA1, A. KOZYREV1, P. BARVITSKYI1, V. SVERDUN1, V. MOSHCHIL1, YU. CHAYKOVSKIY2, M. EISTERER3, L. CHIRKO2, 1V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine (NASU), Kiev, Ukraine; 2Institute for Nuclear Research of the National Academy of Sciences of Ukraine, Kiev, Ukraine; 3Atominstitut, TU Wien, Vienna, Austria
Boron carbide- as well as MAX phases-based materials have high potential for application in fusion reactors, as thick protective coatings for the first wall, in particular. Here the structure and properties of Ti3AlC2, B4C and B4C-SiC, AlB12C2-AlB12-TiB2 composites are under the consideration. After sintering of a-AlB12 with TiC at 30 MPa and 1950 °C into dense composite (74 wt.% AlB12C2, 22 wt.% TiB2, 4 wt.% Al2O3, p=3.2 g/cm3) its demonstrated high mechanical characteristics: HV(9.8N)=48 GPa, K1c(49 N)=7 MPa•m0.5, Rbs=633 MPa and Rcs=640 MPa . Composite B4C-20% SiC sintered at 30 MPa, 2200 °C demonstrated HV(49 N)=30 GPa, K1c (49 N)=5.5 MPa•m0.5, Rbs=474 MPa and Rcs=937 MPa, E=521 МPa. The radiotolerance of the Ti3AlC2-base material was high: K1c of the irradiated sample practically did not change after irradiation with the dose approximately equivalent to that as if the material stayed 4-5 years in the wall of standard reactor opposite to the centre of irradiation active zone. At room temperature Ti3AlC2- based materials (89 wt.% Ti3AlС2) had Hv(4.9N)=4.6-5.8 GPa, Rbs=500-570 MPa, Rcs=700-1300 MPa, and the K1c of the notched sample was more than 10 MPa•√m; the material structure was stable after thermocycling in air up to 1200 °C.
FK:HP06 Thermal Expansion and Shrinkage of a Bentonite Clay Measured by Dilatometry under Humid and Dry Conditions
E. POST, NETZSCH Geraetebau GmbH, Selb, Germany
Bentonite is a clay with a high swelling ability under humid conditions. Due to this behavior and its chemical and physical properties, bentonite is widely used, e.g., in the oil drilling industry for sealing the bore hole. In nuclear waste management, in some countries it is considered or even used as a sealing material in repositories or waste containers. Depending on the water content the volume and density of the bentonite (which consists mainly of montmorillonite) can vary considerably. Below a certain temperature the water loss and uptake is reversible, this means this material contracts during water loss, but also expands again exposed to higher humidity. This behavior was investigated by a TMA connected to a humidity generator using a furnace which can work under humid and dry conditions. In this contribution the experimental design and the measurement results will be presented.
FM:HP10 Nanofilaments at Heat-treated TiO2 (110) for Memristive Devices and Neuromorphic Applications
M. ROGALA1, G. BIHLMAYER2,3,4, W. SPEIER4, C. RODENBÜCHER2,4, P. DABROWSKI1, Z. KLUSEK1, K. SZOT2,4,5, 1Faculty of Physics and Applied Informatics, University of Lodz, Lodz, Poland; 2Peter Grünberg Institut, Forschungszentrum Jülich, Jülich, Germany; 3Institute for Advanced Simulations, Forschungszentrum Jülich, Jülich, Germany; 4JARA- Fundamentals of Future Information Technology, Forschungszentrum Jülich, Jülich, Germany; 5Institute of Physics, University of Silesia, Katowice, Poland
TiO2 is considered as a prototypical memristive material in which resistive switching phenomena allow for nonvolatile information storage . It is now well established that resistive switching in TiO2 crystals is not a material property by itself but is a highly localized phenomenon in the bulk material related to reduction processes and nanofilamentary structures. The temperature treatment method of TiO2 crystals will be described. The thermal preparation method that we propose leads to the modification of extended defects in the crystal and creation of “new” nanofilamentary structures of high density near the surface allowing for preferential and fully controllable bipolar switching. This allows high density data storage by electrical stimulation of quasi-homogenous switchable regions. Based on experimental investigations and simulations we deeply analyze the nature of such crystal structure transformation and the mechanisms responsible for the observed resistive switching processes .
This work is supported by the National Science Centre, Poland (project 2016/21/D/ST3/00955) and by the German Science Foundation DFG (SFB 917 “Nanoswitches”).
 K. Szot, et al. Nanotechnology, 22, 254001 (2011);  M. Rogala, et al. Adv. Funct. Mater., 25, 6382 (2015)
FM:HP11 Anodic Titanium Oxides for Resistive Switching Memories
SHAOCHUAN CHEN, S. NOORI, M.P. PEDEFERRI, M. LANZA, M.V. DIAMANTI, Politecnico di Milano, Chemistry, Materials and Chemical Engineering “Giulio Natta”, Milan, Italy
The interest in titanium and its oxides arises from their peculiar engineered properties, which find applications in several fields, from architecture to bioengineering, from automotive to photovoltaic cells and photocatalytic devices, as well as to produce self-cleaning surfaces. More recently, titanium dioxide thin films in the order of few nanometers of thickness were observed to show resistive switching capabilities, i.e., changing resistance state as a function of external stimuli, which opened new paths for applications in electronics. Here, we present an effective and inexpensive electrochemical method, anodic oxidation, as a means to fabricate titanium oxide/titanium based resistive switching memories. Different electrolytes were employed, both acid and neutral. Anodizing voltage was varied between 2.5 V and 40 V. High-quality and homogeneous titanium oxide films were grown and their thickness was controlled by modifying cell voltage during anodization. Films morphology was characterized by atomic force microscopy, their electrical properties were analyzed both at nanoscale and device scale, obtaining very low variability of breakdown voltage, low operation voltage and high Ron/Roff ratio, up to two orders of magnitude.
FN:HP07 Low-density Carbon Nanotube Micro-yarns: Improving Electrical Properties by Mechanical Processes
C.MIRALAEI1, S. PAILHÈS1, H. LE POCHE2, R. DEBORD1, S. LE FLOCH1, A. SAN-MIGUEL1, J. DIJON2, V. PISCHEDDA1, 1Institut Lumière Matière (ILM), Université Claude Bernard Lyon 1 and CNRS, Villeurbanne, France; 2CEA Liten, Grenoble, France
Carbon nanotubes (CNT) yarns are valued for their light-weight, electrical properties, chemical resistance, and flexibility. Potential markets include applications in smart textiles and implementations into the aerospace industry. CNT micro-yarns could become a light-weight alternative to copper wires in planes and spacecraft where weight is a huge consideration. Though, the challenge remains to harness the properties of individual CNT and mould them into a wire that multiplies their conductive properties, instead of reducing them. Our micro-yarns (of 10 to 20 mm diameter and any desired length) are fabricated from CNTs, first grown onto a substrate and into a dense, vertically-aligned carpet through Chemical Vapor Deposition (CVD). The CNT carpet is then pulled and simultaneously twisted into a yarn by a spinning machine [1, 2]. We are exploring the possibility to improve the electrical performance of dry spinning yarns by mechanical densification and thermal treatment methods. By densifying, the space between CNTs decreases, and more connections between the CNTs are made. Densifying our micro-yarns up to 350 MPa using an autoclave system we were able to improve mechanical strength and to decrease the electrical resistivity of our yarns by 20-25%.
 J. Dijon et al., Nanotech. 2014, vol. 3, pp.17;  N. Chiodarelli et al., Carbon 2013, vol. 60, pp.139
FN:HP08 Recyclable Catalytic Nanoreactors by Magnetic Means
M. AYGUN1, T.W. CHAMBERLAIN2, M. DEL CARMEN GIMENEZ-LOPEZ1, A.N. KHLOBYSTOV3, 1Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain; 2Institute of Process Research and Development, School of Chemistry, University of Leeds, Leeds, UK; 3Nanoscale & Microscale Research Centre, University of Nottingham, University Park, Nottingham, UK
Carbon nanoreactors are excellent supports for creating recoverable and recyclable nanoreactor catalyst systems in an easy, cheap and efficient way for liquid phase chemical reactions due to their low cost, inherent strength, chemical inertness and porous nature. However, wide spread application of carbon nanotube supported catalysts is limited by the lack of a facile and scalable separation technique. In this study, we investigated the the tubular, carbon-based support with nanoscale magnets to enable magnetically induce separation of the solid catalyst from the reaction solution. Both the non-covalent attachment of commercially available graphene-like carbon coated magnetic Co nanomagnets and the in-situ formation of carbon coated iron nanomagnets from a pre‑encapsulated iron complex precursor were expolred. High resolution transmission electron microscopy (HRTEM) showed that they successfully attached to the carbon nanoreactors and the minimum amount of nanomagnets required to enable complete separation of the nanotubes from the solution with an external magnetic field is quantified using UV/Vis spectroscopy. Uncoated, palladium and platinum catalytic nanoparticles were then combined magnetic functionalised materials and the resultant catalytically active and magnetically separable hybrid materials were investigated in the reduction of nitrobenzene. Overall PdNPs combined magnetic functionalised materials demonstrated the highest activity with a TOF of 72.3 min-1 , and high aniline selectivity (85%) at room temperature The recyclability and stability of these magnetic and catalytic nanoreactors were found to be highly active in the reduction of nitrobenzene whilst magnetic recovery enabled negligible catalyst loss (< 0.5% by wt.) over five reaction cycles in comparison to that of filtration based catalyst recovery (>10% catalyst loss by wt.).
FO:HP04 Optical Evidence on the Unconventional Superconductivity in Ca8.35La1.65(Pt3As8)(Fe2As2)5 Single Crystal
YONG SEUNG KWON, YU-IL SEO, WOO-JAE CHOI, DGIST, Emerging Materials Science, Daegu, Korea
Many models have been proposed to explain the glue binding the electrons in an unconventional superconductor. Among the models, a novel and plausible mechanism has been proposed in which the carriers lower their kinetic energy upon pair formation. Optical analysis is an important key to the validity of this model. Here, we report that when the strong correlated superconductor Ca8.35La1.65(Pt3As8)(Fe2As2)5 enters the superconducting state, the transfer of the spectral weight over a broad range of high frequency occurs. The reduced spectral weight is transferred to zero frequency. The high frequency spectral weight transfer induces the reduction of kinetic energy of strongly correlated electrons. The kinetic energy lowering derived from the measured spectral weight transfer in superconducting state is large enough to account for the condensation energy of this material.
FO:HP05 Thermal Relaxation Time of Superconducting NbTi Strips deduced from the Nucleation Time of Current-induced Hot Spots
K. HARRABI1, A. MEKKI1, N. MAALEJ1, K. GASMI1, J.P. MANEVAL2, 1Physics Department, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia; 2Laboratoire de Physique LPA, Ecole Normale Supérieure, Paris, France
We have studied the voltage response of superconducting NbTi strips to a step-pulse of supercritical current (I > Ic), where Ic is the pair-breaking current. The destruction of the superconducting Cooper pairs leads to a transition into the normal state where either a phase-slip center is nucleated or a hotspot is formed. In both cases, the voltage response occurs after a delay time td , which can be analyzed through a Time-Dependent Ginzburg-Landau (TDGL) theory due to M. Tinkham. The gap relaxation time tau_Delta is subsequently deduced from fitting the experimental data with the TDGL theory. An agreement is found by choosing an effective tau_Delt = 6.1 ns for a film thickness of 80 nm, whatever the sample width. Assuming the proportionality to sample thickness, this indicates a thermal relaxation time of 73 ps per nm, for a NbTi film sputtered at room temperature on polished crystalline Al2O3. If one assumes between the electron and the phonon specific heats the same ratio as for pure Nb, there results a phonon escape time of ~ 25 ps/nm.
FO:HP06 Superconductivity in Pressurized CeRhGe3 and Related Noncentrosymmetric Compounds
HONGHONG WANG1,3, JING GUO1, E.D. BAUER2, V.A. SIDOROV4, HENGCAN ZHAO1,3, JIAHAO ZHANG1,3, YAZHOU ZHOU1, ZHE WANG1,3, SHU CAI1,3, KE YANG5, AIGUO LI5, XIAODONG LI6, YANCHUN LI6, PEIJIE SUN1, YI-FENG YANG1,3, QI WU1, TAO XIANG1,3, J.D. THOMPSON2, LILING SUN1,3, 1Institute of Physics, National Lab. for Condensed Matter Physics, CAS, Beijing, China; 2Los Alamos National Laboratory, MS K764, Los Alamos, NM, USA; 3University of Chinese Academy of Sciences, Beijing, China; 4Institute for High Pressure Physics, RAS, Troitsk, Moscow, Russia; 5Shanghai Synchrotron Radiation Facilities, Shanghai Institute of Applied Physics, CAS, Shanghai, China; 6Institute of High Energy Physics, CAS, Beijing, China
Superconductivity in non-centrosymmetric compounds is one of the most important issues to be clarified experimentally and theoretically. We found the pressure-induced superconductivity in CeRhGe3, a non-superconducting member of the isostructural family of non-centrosymmetric heavy-fermion compounds CeTX3 (T = Co, Rh, Ir and X = Si, Ge). Superconductivity appears in CeRhGe3 at a pressure of 19.6 GPa and the transition temperature TC reaches a maximum value of 1.3 K at 21.5 GPa. This finding provides an opportunity to establish systematic correlations between superconductivity and material properties within this family. Though ambient-pressure unit-cell volumes and critical pressures for superconductivity vary substantially across the series, all family members reach a maximum T_c^max at a common (±1.7%) critical cell volume Vcrit, and T_c^max at Vcrit increases with increasing spin-orbit coupling strength of the d electrons. These correlations show that substantial Kondo and spin-orbit couplings favor superconductivity in this family, the latter reflecting the role of broken centrosymmetry.
FO:HP07 Fabrication of Y1Ba2Cu3O7-d Films using Trifluoroacetates on SrTiO3 and YSZ Substrates
A. BUSTAMANTE DOMINGUEZ1, L. DE LOS SANTOS VALLADARES2, 3, A. M. OSORIO ANAYA4, H. SANCHEZ CORNEJO1, J. FLORES SANTIBAÑEZ1, L. SANCHEZ SOVERO1, C.H. BARNES2, 1Lab. de Cerámicos y Nanomateriales, Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Lima, Perú; 2Cavendish Lab., Dept. of Physics, University of Cambridge, Cambridge, UK; 3School of Materials Science and Engineering, Northeastern University, Heping District, Shenyang, China; 4Lab. de Nanotecnología e Innovación Tecnológica, Fac. de Química e Ingeniería Química, Universidad Nacional Mayor de San Marcos, Lima, Perú
We present a cheap production technique for the fabrication of Y1Ba2Cu3O7-d (YBCO) films on SrTiO3 and YSZ substrates, that is, without the requirement of tedious process or expensive high vacuum equipment . The process involves the deposition of a chemical solution (DCS) previously prepared by metallo-organic deposition (MOD) method using trifluoroacetate (TFA) reagents: Ytrium hydrated Y(OOCCF3)2•xH2O, Barium hydrated Ba(OOCCF3)2•xH2O and Copper hydrated Cu(OOCCF3)2•xH2O which are transformed into BaF2, CuO and Y2O3 by a pyrolysis process. This prevents the formation of the unwanted BaCO3compound and the BaF2 decomposes at a high temperature. The process includes calcination and sintering with oxygen flow at the temperatures 820, 840, 860 and 880°C. The X-ray diffraction reveals that all the samples contain crystallites oriented to (00l) indicating epitaxial growth of the film in the c-direction. Despite minor formation of Y2BaCuO5 (Y211) and CuO as secondary phases, the technique shows successfully formation of superconducting YBCO films onto SrTiO3 and YSZ substrates at 880°C. Rocking curve (RC) corresponding to the (005) reflection of the YBCO film on SrTiO3 substrate prepared a 860°C was fitted with one Gaussian function with FWHM of 0.44° meaning that they consist of multilayers of YBCO with different texture. Similarly the RC for sample grown on YSZ (880°C) was adjust with two Gaussian functions, one corresponding to the YBCO layer (FWHM 0.4°) and the another to the substrate (FWHM 0.3°). The magnetic measurements taken in Zero Field Cooling (ZFC) and Field Cooling (FC) modes confirm the formation of the superconducting YBCO with TC=87,5 and 83,4 K for the samples grown onto YSZ and SrTiO3, respectively.
 X Obradors, T Puig, S Ricart, et al 2012Superconduc. Sci. Technol. Vol, 25 123001
FP:HP11 αTCP Based Bone Cements with Silver-doped Hydroxyapatite and CaCO3
A. SLOSARCZYK, D. SIEK, A. ZIMA, AGH-University of Science and Technology, Krakow, Poland
Novel biomaterials not only stimulate bone healing, but also prevent and treat eventual bacterial infections. The aim of this study was to develop, fabricate and evaluate the cement-type functionalized composites containing αTCP, silver-doped hydroxyapatite (Ag-HA) and calcite (CaCO3). The initial powders (αTCP and Ag-HA) were synthesized by the wet chemical method using CaO, H3PO4 and CH3COOAg. After drying powders were heat treated in different temperatures. Materials were obtained by mixing together solid P) and liquid L) phases (methylocellulose solution or chondroitin sulphate solution). Setting times of cement pastes as well as phase compositions, microstructure, mechanical strength, chemical stability and cohesion of the final materials were evaluated. The developed materials revealed good surgical handiness and appropriate setting times allowing for their easy application to bone defects. He open porosity of hardened products was from 40 to 50 vol.%. The pores size was less than 0.7µm. Materials possessed compressive strength ~ 10 MPa. After 28 days incubation in SBF samples revealed good cohesion.
Research funded by Faculty of Materials Science and Ceramics AGH University of Science and Technology - Project No.22.214.171.1247 (2018).
FP:HP12 The Microconcrete Type Bone Implant Materials on the Basis of Calcium Phosphates and Chitosan
A. ZIMA, A. SLOSARCZYK, E. CICHON, J. CZECHOWSKA, AGH-University of Science and Technology, Krakow, Poland
Still poorly examined form of bone substitutes are biomicroconcretes which are a specific type of composites for medicine. Literature studies revealed that there are not reports concerning the preparation of above biomaterials in the system: αTCP-HA-chitosan. Original, innovative aspect of the present work was to obtain the new biomicroconcretes-type bone implant material with hybrid HA/CTS granules as aggregates embedded in the CaP matrix. The main initial materials i.e. highly reactive α-tricalcium phosphate powder and hybrid HA/CTS composites powder were synthesized by the wet chemical methods. As the liquid phases methylcellulose and chitosan solutions were used. Homogenous chemicaly bonded materials were obtained. Highly reactive, monophasic αTCP powder used as the setting agent guaranteed a good adhesion of the continuous cement phase to the surface of the HA/CTS granules. Setting times of developed materials ranged from 5 to 6 min – initial and from 24 to 28 min – final. Obtained microconcretes exhibited a high total open porosity (50 vol.%) and contained open pores in the range of 0.01 - 20 microns what let us to assume that such materials can be used as carriers of drugs administered directly to the bone.
Research funded - Project No.126.96.36.1997 (2018).