bluuebunny/crossref_metadata_2025 huggingface dataset:
Anodized Porous Oxide Thin Films for Energy Application
Authors: Cheng Hua , Zhang Dehui , Wu Dong , Lu Zhouguang
Published: February 2020

Highly ordered porous oxide thin films including Fe3O4, NiO, ZnO, CuO, Co3O4 have been prepared by a facile multi-pulse electrochemical anodization method. The as-obtained oxide films are directly grown on the corresponding metallic substrate, featuring nano-channels with periodically rugated channel walls running throughout the film thickness direction and can also be peeled off from the substrate to become free-standing. The geometry and size of the films can be finely tuned by the electrochemical anodization parameters. The fabricated oxide films have been intensively applied as electrode materials for lithium ion batteries and micro-combustion. Very promising performance has been achieved due to the very special periodic rugated nanostructures of these anodized thin films.

Acknowledgments

This work was financially supported by the Shenzhen Peacock Plan (KQCX20140522150815065), the Natural Science Foundation of Shenzhen (JCYJ20150630145302231) and the Science and Technology Innovation Foundation for the Undergraduates of SUSTC (2015x19 and 2015x12).

References

[1] H Cheng, R Xiao, HD Bian, et al. Mater. Chem. Phys.
2014, 144, 25.

[2] H Cheng, ZG Lu, RG Ma, et al. J. Mater. Chem.
2012, 22, 22692.

[3] H Cheng, SW Shu, ZG Lu, et al. J. Appl. Phys.
2014, 116, 153511.

Figure 1
Improving the Electrolytic Hydrogen Production Using Co-Cu-Mo Based Ionic Activator
Authors: Marceta Kaninski Milica P , Maslovara Sladjana Lj , Lausevic Petar Z , Saponjic Djordje P , Nikolic Zeljka M , Tasic Gvozden S , Nikolic Vladimir M
Published: February 2020

Alkaline water electrolysis is used when there is a need for the efficient, on-site production of the high purity hydrogen and oxygen, especially when coupled to the renewable energy sources, such as wind and solar energy. Hydrogen produced in this way can be stored and transported for remote power generation in fuel cells. In order to expand commercialization of the alkaline electrolyzers, operating and capital costs should be reduced. High power consumption of the electrolytic process could be decreased by using more efficient electrode materials, keeping in mind its costs. This manuscript presents a contribution on the improved efficiency of the alkaline electrolytic production of hydrogen by in situ adding activating compounds directly into the electrolyte during the electrolytic process. New elec­trode material was formed, based on the mixture of co-deposition of Co and Cu complexes and Mo oxide, applied as activating compound i.e. ionic activator. Electrocatalytic efficiency of ternary system CoCuMo was studied using quasi-potentiostatic, galvanostatic and impedance spectroscopy techniques. The electrodeposited ionic activator on the plain nickel electrode, is shown to have a great influence on the kinetics of the hydrogen evolution reaction, lowering the overvoltage for about 300 mV at current density of 100 mA cm-2. Morphological investigations using SEM shows formation of the porous structure on the cathode resulting in significant increase of the surface area, and UV/VIS spectra of the electrolyte, recorded during the electrolytic process shows decreased concentrations of the ionic activators making a deposit on the surface of the Ni cathode. This ionic activator was applied in the laboratory alkaline electrolytic cell and we found that the energy requirements per mass unit of hydrogen produced is reduced for more than 20%, compared to non-activated system, when operated at elevated temperatures. The use of the in-situ activation with CoCuMo based activators added directly into alkaline electrolyte could be of great interest, since it offers simplified electrode preparation procedure and provides reduction in the alkaline electrolyzer operating cost.

Figure 1
Bimetallic Pt-Based Electrocatalysts Supported on Carbon Fiber for Coal Electrooxidation to Produce Hydrogen
Authors: Yu Ping
Published: February 2020

The electrolysis of coal slurries to produce hydrogen is a new approach to utilize coal in a clean and efficient manner [1, 2]. However, various results show that the process is less favorable kinetically [3-7]. Therefore, it is important to explore the design of new electrocatalysts with emphasis towards high activity, low cost, and long life.

It is well known that Pt-based bimetallic catalysts containing a transition metal, such as Pd, Co, Fe, Ti, Ru and Sn, often demonstrate improved catalytic performance compared to pure Pt catalysts [8-12]. Significant effort has been made to employ bimetallic catalysts that can decrease the content of noble metals and improve performance based on bi-functional properties.

In this work, Pt-based bimetallic electrode supported on carbon fibers (CFs) was prepared by the impregnation and reduction and evaluated for the electrolysis of coal to produce hydrogen. The characterization of the electrocatalyst of Pt-based bimetallic electrocatalysts using XRD, TEM, and SEM/EDS is performed. The activity and stability of the electrodes prepared are simultaneously investigated.

References:

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O.J. Murphy, J.O. Bockris, D.W. Later, Int. J. Hydrogen Energy 10 (1985) 453-474.

R.W. Coughlin, M. Farooque, Nature 279 (1979) 301-303.

Sathe N, G.G. Botte, Journal of Power Sources, 161(2006)51

Abreu YD, Patil P, Marquezal, G.G. Botte,Fuel,86(2007)57

Nilesh Sathe, Gerardine G. Botte, Journal of Power Sources 161 (2006) 513

Prashanth Patil, Yolanda De Abreu, Gerardine G. Botte, Journal of Power Sources 158 (2006) 368

A.U. Nilekar, S. Alayoglu, B. Eichhorn, M. Mavrikakis, J. Am. Chem. Soc. 132 (2010) 7418-7428.

T. Komatsu, A. Tamura, J. Catal. 258 (2008) 306-314.

Q. Fu, W.X. Li, Y.X. Yao, H.Y. Liu, H.Y. Su, D. Ma, X.K. Gu, L.M. Chen, Z. Wang, H. Zhang, B. Wang, X.H. Bao, Science 328 (2010) 1141-1144.

A. Siani, B. Captain, O.S. Alexeev, E. Stafyla, A.B. Hungria, P.A. Midgley, J.M. Thomas, R.D. Adams, M.D. Amiridis, Langmuir 22 (2006) 5160-5167.

G. Saravanan, H. Abe, Y. Xu, N. Sekido, H. Hirata, S. Matsumoto, H. Yoshikawa, Y. Yamabe-Mitarai, Langmuir 26 (2010) 11446-11451.
(Invited) An Impedance Study of the Factors Affecting the Passivity of Steel in Concrete
Authors: Deus J.M. , Díaz B. , Nóvoa X.R. , Pérez M. C.
Published: February 2020

Reinforced concrete is one of the materials used most often in civil construction thanks to its unique low ratio of cost to mechanical performance. Although reinforced concrete elements and structures are expected to last for several generations, everyday experience shows that this is not true and repairing measures are often necessary after only few years of being in service.

The chemical stability of the steel reinforcements lies in the formation of the passivation layer whose stability is the key for durability. The passive layer degrades in low pH environments, that occurs in carbonated concrete, and in the presence of chlorides that are typical of marine environments.

Although carbonation and chlorides are the main factors that affect the durability of reinforced concrete structures, the exposure conditions have also to be considered for reliable lifetime predictions. Wetting/drying cycles and temperature can be cited among the most relevant environmental factors involved.

The present communication aims at reviewing the recent literature on the effect of temperature in both the concrete cover and the passive layer, to introduce new data on EIS measurements performed on samples exposed up to 15 years outdoors.
(Invited) Electrochemical Impedance Analysis of Printable Porous Carbon Electrode for Realization of High-Power Biofuel Cell and Wearable Self-Powered Biosensor
Authors: Shitanda Isao , Hoshi Yoshinao , Itagaki Masayuki
Published: February 2020

A paper-based biofuel cell (PBFC) have been attracted as a potential application as energy harvesting power sources in the Internet of Things (IoT) field [1-3]. To use the PBFC for practical application, the cell power density of PBFC, generally limited by the biocathode performance, should be improved. The distance between the redox site of the enzyme and the electrode material surface is one of the key factors for biocathode development. By entrapping enzymes in a mesopore of a porous carbon material, the redox center can approach the electrode material surface with high probability. In addition, the stability of the enzyme may be improved. A branch structure (double pore structure) porous carbon material is a suitable porous material for biosensors and biofuel cell electrodes, because the branch structure porous carbon material such as MgO-templated mesoporous carbon (MgOC) has large specific surface areas and mesopores whose size can be easily controlled. In the present study, we formed the branch structure porous carbon electrodes for biofuel cathode by screen-printing technique, and the electrode performance was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy (EIS) to improve the electrode structure for biofuel cell cathode. In the present paper, we discuss the experimental result in detail and introduce our wearable PBFC performance using the printed porous carbon electrodes.

[1] I. Shitanda et al., Chem. Commun. 49 (2013) 11110.

[2] Claudia W. Narváez Villarrubia et al., Electrochem. Commun, 45 (2014) 44.

[3] Carolin Lau et al., Int. J. Hydrogen. Energy, 42 (2015) 14661.
The Joint Center for Energy Storage Research: Integration of Research, Development, and Demonstration
Authors: Brushett Fikile R. , Trahey Lynn , Hodge Devin
Published: February 2020

The Joint Center for Energy Storage Research (JCESR) seeks transformational change in transportation and the electric grid driven by next generation high performance, low cost electrochemical energy storage. To pursue this transformative vision JCESR introduces a new paradigm for battery research: integrating discovery science, battery design, research prototyping, and manufacturing collaboration in a single highly interactive organization. This new paradigm aims to accelerate the pace of discovery and innovation and to reduce the time from conceptualization to commercialization, thereby crossing the famed “valley of death” between research and industry. While JCESR exclusively focuses on beyond lithium-ion batteries, this paradigm is portable and can be applied to a wide range of challenging problems facing today’s scientists and engineers. To this end, this talk will present JCESR’s motivation, vision, mission, strategy, and intended outcomes or legacies. Lessons learned in the development, execution, and refinement of this Hub will be discussed and key accomplishments enabled by this new mode of operation will be highlighted.
Nano Crystals to Micro Crystals: Organolead Triiodide Perovskite Crystal Growth from Isopropanol Solution
Authors: Johansson Malin Birgitta , Edvinsson Tomas , Bitter Stefan , Eriksson Anna I. K. , Johansson Erik M. J. , Göthelid Mats , Boschloo Gerrit
Published: February 2020

Perovskite-absorber solar cells have become a research area with high interest for their efficient energy conversion. A clue to the high performance of the material is the long diffusion length of charge carriers, which depend on crystallinity and morphology. However, still the main difficulty is to gain reproducible performance which address questions to the functions originating from the crystal chemistry in these materials. The first crystallographic information is commonly X-ray diffraction for organo-metal halide perovskites, but scattering is dominated by higher atomic elements, and is relatively insensitive to the organic component that controls the phase and crystal formation [1]. By combining different characterizations techniques as TEM, SEM, Raman, XRD and ED we study perovskite crystals formed from a mixture of both stoichiometric and non-stoichiometric II-propanol solution of methyl ammonium iodide and lead iodide. A comparison of different crystals with its electron and x-ray diffraction pattern gained knowledge in how the material is built up. It is seen how the atoms organize from small perovskite quantum dots to larger single crystals. The size and structure of the crystals can further be controlled by molar ratio, additives and temperature. Here we try to illuminate and explain the crystal structure birth and its organized growth of the perovskite grains. This is combined with optical characterization; UV/vis/NIR spectrophotometry and photoluminescence spectroscopy of the spin-coated solution on a substrate. The comparably environmental friendly II-propanol evaporates fast after spin-coating and large single crystal grains are formed. The combined results give new insight into the crystal chemistry of the perovskite solar cell material.

Figure 1
(Invited) Semiconductor Packaging Technology to Progress the IoT Era
Authors: Takeno Yasuhiko
Published: February 2020

In the world economy there is a wave of the booming economy and the recession, the wave of the booming economy is going by the industry of technology innovation. Until now, the invention of the steam engine, transportation of development, has been repeated waves of good / recession of the economy by the invention of the electrical / communication. Now, the wave of major technological innovation has been visited by the progress of the Internet and the computer. It is a technique called IoT (Internet of Things) is connected and all of the places and things in the Internet, to accumulate an enormous amount of information, a wave of AI (Artificial Inteligence) is going to processing.

Server for IoT era is referred to as a sensor and the edge can be determined that data to collect the information, also AI server to handle Big Data is needed. Such sensors or servers, it is important to semiconductor development for processing data in high-density memory and fast. On the other hand due to the limit of the semiconductor of the fine or photolithography, it is no longer the case is Moore's Law. As a result, technology of packaging the device in a high density is important. DRAM is, TSV (Through Via Silicon) HBM using (High Band Width Memory) and HMC (Hybrid Memory Cube) has been mass-produced is already a memory. System connecting the GPU (Graphic Processor Unit) using the Si interposer called 2.5D is still being produced.

However, TSV Si Interposer called these 3D is in the advance in the future IoT because of the high cost, it is difficult to be used in general to modularize the large number of sensors. Development has been the development of new packaging technology, such as that in FOWLP.

I want to discuss the outlook and its Overview.
Effects of Brighteners on Throwing Power and Thermal Reliability of Plating through Holes in a Copper Plating Bath
Authors: Chen Tsu-Chi , Tsai Yao-Lin , Hsu Chia-Fu , Dow Wei-Ping
Published: February 2020

High aspect ratio through holes are commonly designed in printed circuit boards (PCBs) with a high density interconnection. In order to achieve high copper throwing power of through holes by using plating, the copper plating bath has to be added with additives, like chloride ions, suppressors, brighteners and levelers. In this study, several brighteners were screened to understand their performance on copper throwing power of plated through holes (PTHs). The chloride ion concentration was fixed at 60 ppm and the suppressor, Polyethylene glycol, concentration was fixed at 200ppm.The brighteners were 3-mercapo-1-1-propanesulfonate（MPS）, 3-S-Thiuronium-propanesulfonate (UPS) and 3-(benzothiazolyl-2-mercapto)-proyl-sulfonate（ZPS）. Good throwing power of PTHs appeared at 1 ppm MPS, 20 ~ 100 ppm UPS or 20 ~ 60 ppm ZPS. Scanning Electron Microscope（SEM）shows that the electroplated morphology is related with the brightener concentration. Moreover, different brightener results in different plated copper orientation and stress in the copper deposit, which significantly influences the final thermal reliability of the PTHs. The results show that the PTHs with the highest copper TP, which were obtained at 1 ppm MPS, 10 ppm UPS, and 20 ppm ZPS, can pass the thermal shock for 5 cycles.

Key words: Throwing power, Reliability, Brightener, Through hole.

References:

1. W.-C. Tsai, C.-C. Wan, and Y.-Y. Wang, J. Electrochem. Soc., 150, C267 (2003).

2. C. Wang, J. Zhang, P. Yang, B. Zhang, and M. An, J. Electrochem. Soc., 160, D85 (2013).
(Invited) Interconnect Metals for Future Integrated Circuits
Authors: Besser Paul , Wu Hui-Jung , Jiang Yu , Chattopadhyay Kaushik , Brogan Lee , Zhao Larry , Doubina Natalia , Nalla Praveen , Kolics Artur
Published: February 2020

The highest performing microprocessors, memory devices, and other computer chips require the most advanced technologies. Improving performance of the device is much more than just shrinking the dimensions: it requires novel materials innovations. BEOL interconnect performance has been improved by the migration from aluminum-based interconnects and oxide interlayer dielectrics to copper interconnects in a dual inlaid architecture and with low-k dielectrics. Inlaid Cu lines offer higher conductivity, improved electromigration resistance, and a reduced cost of manufacturing; however, as feature sizes continue to scale, metals to replace Cu are being researched. In this presentation, the novel materials innovations being researched to enhance performance, improve reliability, and enable technology scaling for the integrated circuit (IC) industry will be highlighted. A historical perspective on BEOL interconnect challenges and innovations to reduce capacitance and improve conductivity will be shown.  Future BEOL interconnect metallizations will be critically reviewed.
High Performance and Flexible Si Anodes Enabled By a Facile Electrode Design
Authors: Feng Kun , Li Matthew , Chen Zhongwei
Published: February 2020

As the traditional LIB electrode materials approach their theoretical limits, new electrodes that can provide much higher energy densities have attracted significant research interest. Silicon, which undergoes an alloying mechanism with lithium, possesses a theoretical capacity of around 3500 mAh g-1, and has aroused tremendous attention. However, Si anodes usually suffer from several intrinsic problems, including self-pulverization, delamination, unstable SEI, etc. It is indispensable to address these challenges before Si anodes can be employed in large-scale “real-world” applications. In this work, high performance and flexible C-SiNW-FB anodes were designed and prepared via a facile method. 1-D Si NWs were in-situ grown and coated with a thin-layer of carbon on a flexible carbon cloth (CC) substrate, and a functional polymer binder was subsequently applied to intertwine with SiNWs, forming a stable C-SiNW-FB matrix on CC. This advanced electrode design presents the electrode with good flexibility, high capacity, as well as stable cycling performance. Furthermore, the amount of active material on the electrode can be easily manipulated during the synthesis procedure, and electrodes with high loading mass of active materials have been obtained. The C-SiNW-FB electrodes deliver a specific capacity of 3000mA h g-1, corresponding to areal capacity of 5.87 mAh cm-2. Cycling program with a current density of 1A g-1 was performed with the material, and capacity retention of 98% was achieved after 130 cycles. Extremely high loading of 10 mg cm-2 of the active Si was achieved, delivering a much higher areal capacity than commercial graphite anodes. Good flexibility, high specific and areal capacity, together with the stable cycling, all bode great potential for C-SiNW-FB as a promising candidate to fulfill the high energy density needs of next generation batteries.
Modeling Investigation of Influencing Factors on Li Plating of Li-Ion Battery
Authors: Zhang Zhenli , Jin Zhihong , Wyatt Perry M
Published: February 2020

Lithium plating is a known issue of rechargeable lithium-ion cells with carbon-based anodes. Accumulated metallic lithium plating growth accelerates aging and internal short circuit failures. Preventing lithium plating is an important consideration for cell design and operations. In real world applications, the cells in battery pack will age and very likely they age differently and sometimes they are used in extreme conditions and then it raises questions of how to detect and control lithium plating in service. A variety of factors influence lithium plating including cell design variables, intrinsic material properties, manufacturing conditions, as well as cell operation conditions. Understanding these factors has significant value in points of view of design and controls. Where are the optimization rooms in battery design without raising plating risks? How to determine the charging current limits as function of temperature, state of charge and battery conditions? Using experimental means to investigate plating has limitations in sensitivity and timeliness because in many scenarios plating does not show up in a detectable quantity and sometimes they are not stable.

In this work, we develop a model to consider lithium plating. In the framework of electrochemical modeling the lithium plating reaction is included. The model is used to study lithium plating upon various design variables and application conditions. We are interested in how coating thickness, particle size characteristics, pulse current and duration, and driving cycles affect lithium plating. The aim of this modeling is to understand the relative impacts of these factors and provide guidance for cell designs and controls.
Advanced Performance of Concentration Gradient Core-Shell Li[Ni0.95Co0.025Mn0.025]O2 Cathode Materials for Lithium Ion Batteries
Authors: Jun Do-Wook , Sun Yang-Kook
Published: February 2020

Concentration Gradient Core-Shell (CGCS) cathode material with Ni-rich core and shell in concentration gradient with lower Ni and higher Mn content compared to the core was synthesized via co-precipitation method. This CGCS material represents nominal composition of Li[Ni0.95Co0.025Mn0.025]O2. We have evaluated electrochemical and thermal properties of the CGCS cathode material and conventional cathode (CC) material Li[Ni0.95Co0.025Mn0.025]O2 without the concentration gradient. CSCG material exhibited superior cycle retention and improved thermal stability compared with the CC material by the benefit of relatively higher Mn content on surface.
The Examination of the Composition of xLi2MnO3-yLiNi0.5Mn0.5O2-zLiNi1/3Co1/3Mn1/3O2 Solid-Solution Cathode Materials Exhibiting High Capacity, Discharge Voltage and Rate Performance
Authors: Miyamoto Koki , Gunji Takao , Mochizuki Yasumasa , Kaneko Shingo , Tanabe Toyokazu , Ohsaka Takeo , Matsumoto Futoshi
Published: February 2020

Lithium-ion batteries (LIBs) have become the state-of-the-art power source for portable appliances, such as notebook computers, cellular phones, and digital cameras, and a prime candidate for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and electric vehicles (EVs) because of their high energy density, high power density, superior cyclability and safety. The development of a higher capacity cathode material in particular is a matter of great urgency for the automobile industry because the currently attainable capacity of commercially available cathode materials for Li-ion batteries, such as LiCoO2 and LiMn2O4, is much lower than that of anode materials, which limits the expansion of LIB usage. A great deal attention has recently been focused on the Li-rich solid-solution layered cathode material Li2MnO3-LiMO2 (M = Co, Ni, etc.), which exhibits a discharge capacity of more than 200 mAhg-1 when operated above 4.6 V. The structural compatibility between Li2MnO3, which is electrochemically inactive and has a large theoretical capacity, and LiMO2, which is electrochemically active but has lower capacity, allows for the structural integration of these components at the atomic level. As a result, the electrochemically inactive Li2MnO3 can participate in the charge/discharge process after activation with oxygen release from the lattice during the charging process, while the capacity of LiMO2 can be improved by the stabilization of the layered LiMO2 structure by the Li2MnO3 component when more than 50% of the Li+ ions are deintercalated. In this study, the performance of the cathode material was investigated in detail by varying the charge/discharge voltage limits, cycle numbers, and current densities during pre-treatment [1] to reduce the duration of the pre-cycling process. In addition, search of composition of Li2MnO3-LiMO2 (M = Co, Ni, etc.) which exhibits high capacity and its duration and do not exhibit the decrease in the average discharge voltage with charge/discharge cycles was done. Specifically, the examined cathode material is considered to be solid-solution of Li2MnO3, LiCo1/3Ni1/3Mn1/3O2 and LiNi0.5Mn0.5O2. The relationship between the percentage of Li2MnO3, LiCo1/3Ni1/3Mn1/3O2 and LiNi0.5Mn0.5O2 in the solid-solution cathode material and the cathode performance mentioned above was examined with the half coin cells that were fabricated with the cathode and Li metal anode.
Fabrication and Characterization of SiGe on Insulator through Condensation and Wafer Bonding Techniques
Authors: Noroozi Mohammad , Hamawandi Bejan , Toprak Muhammet , Radamson Henry H.
Published: February 2020

SiGe on insulator (SGOI) is desired to obtain microelectronic devices with high performance and low leakage current. The manufacturing of silicon on insulator (SOI) has been already developed and the wafers are on the market with different expenses and qualities. Nevertheless the fabrication techniques of SGOI is more complex than SOI wafers.

In this study two different techniques has been applied to fabricate SGOI wafers. The advantages and disadvantages of both techniques have been discussed in details and the wafers have been characterized in terms of defect density, roughness, uniformity and fabrication process parameters.

The original wafers for condensation technique were SOI with 50 nm Si top and 400 nm buried oxide. The 100 nm Si0.74Ge0.26 was epitaxially grown on SOI wafers followed by 10 nm Si cap layer using chemical vapor deposition (CVD) technique. The Si cap/ Si0.74Ge0.26/ Si structure went through condensation where Si cap layer oxidize immediately and Si0.74Ge0.26/Si was sandwiched between two oxide layers. The consequence of Ge diffusion to the beneath Si layer result single layer Si0.53Ge0.47on insulator (SGOI).

In the wafer bonding technique as second method, Si0.53Ge0.47 has grown epitaxially on a Si wafer. The direct bonding applied between donor and acceptor wafers. The bonded wafers are then annealed in order to strength the bonding. The etch-back process begins by thinning down the donor wafer to leave the Si0.53Ge0.47 on insulator.

The quality and electrical transport of condensed and bonded SiGe layer were examined using high resolution reciprocal lattice mapping (HRRLM), scanning electron microscopy (SEM), Rutherford back scattering (RBS), atomic force microscopy (AFM), hall measurement technique in van der pauw structure and four probe measurement technique. The results show the condensation layer undergo defects which originate from condensation process compared to bonding layer which possess lower defect density. This study will help to continue optimizing of substrate engineering of group IV alloys for implementation on next silicon technology.
Zno Nanowires Electrodeposited for UV Detector Applications
Authors: V. Manzano Cristina , Pethö Laszlo , Michler Johann , Philippe Laetitia
Published: February 2020

In the last years, wide band gap semiconductors have received great interest due to their wide application range. Specifically, one-dimensional structures of these semiconductors are candidates for many applications. ZnO is an ideal candidate, as it is an n-type semiconductor with a hexagonal structure, a direct wide band gap of 3.36 eV, high electron mobility, and large excitation energy of 60 meV at room temperature. This semiconductor exhibits an efficient emission in the ultraviolet and visible range, so it is also promising for UV detection applications. ZnO one-dimensional structures (nanowires) are a promising candidate for efficient UV detectors if they fulfill three requirements: high aspect ratio (length/pore diameter) to obtain high on/off current ratios in UV detectors, oriented along the c-axis of the hexagonal structure to reach high electrical properties for the photodetector, and ZnO nanowires should be ordered perpendicular to the substrate to provide excellent light trapping and improve absorption.

In this study, ZnO nanowires have been grown at constant electrochemical deposition. Electrodeposition of ZnO was performed using a standard three-electrode cell, where the working electrode was home made anodic aluminum oxide (AAO) templates, the counter electrode was a Pt mesh, and the reference electrode was Ag/AgCl. The electrolyte used in the electrodeposition was peroxide solution (0.005 M ZnCl2 + 0.1 M KCl + 0.04 M H2O2). ZnCl2 concentration were changed from 0.001 M to 0.01 M. The electrodeposition temperature was 70, 75, and 80 °C. The morphology, uniform growth, and filling ratio were controlled by the ZnCl2 concentration, applied potential, and electrodeposition temperature. At 70 °C and using 0.005 M ZnCl2 in the electrolyte, high aspect ratio, uniform growth, and filling ratio ZnO nanowires were obtained by Scanning Electron Microscopy. The crystallographic structure of the nanowires was controlled by applied potential around the reduction potential of ZnO. X-Ray Diffraction confirms that the nanowires are pure ZnO. The main advantages of growing ZnO nanowires by electrodeposition into AAO are the order of the nanostructures, and perfect control nanowires geometry. Moreover, the electrical properties can be measured in ZnO nanowires embedded into AAO, after removing AAO, and single nanowires. The effect of the pore diameter and length of ZnO nanowires on IV curves, and photoresponse is a wide field waiting to be explored.
Turning the n-Type CdS to p-Type CdS Nanowires By Surface Charge Transfer Doping
Authors: Chen Hsin-Ju , Wang Hsiang-Chen , Lu Ming-Pei , Lu Ming-Yen
Published: February 2020

One-dimensional semiconductor nanostructure has been attracted great attention in electronic and optoelectronic applications in recent years. N-type CdS nanowires (NWs) doped with gallium were synthesized via chemical vapor deposition method[
1
]. In contrast to have n-type doping for CdS, p-type doping is relatively difficult to achieve due to the strong self-compensation [
2,3
]. In this work, we emonstrated the p-type doping of CdS NWs can be achieved by coating ~ 100 nm MoO3 onto CdS surface. Owing to the large work function of MoO3, the electrons in CdS are transfer to MoO3 and CdS exhibits the p-type characteristics, this process is called surface charge transfer doping. The charge transfer process was analyzed by X-ray photoelectron spectroscopy. MoO3-coated CdS NWs were then confirmed to be p-type by the back-gate field-effect transistors (FETs). Fig. 1(a) shows the optical microscopy image of back-gate Ga-doped CdS NW FET device. Fig. 1(b) depicts drain current (Id) versus drain voltage (Vd) at gate voltages (Vg) ranging from -30 V to 30 V at room temperature, it reveals typical n-type behavior. Besides, the transfer characteristic curves (Id-Vg) of Ga-doped CdS NW and MoO3-coated CdS NW devices shown in Fig. 1(c) as black and red curves, respectively. It is obvious that Ga-doped CdS NW reveals p-type characteristic after MoO3 layer coating. Finally, the MoO3-coated CdS/CdS NW junction photovoltaic devices were fabricated and discussed.

Reference

Cai, Jiajun et al., Phys. Chem. Chem. Phys., 13, 14663-14667, 2011

Xie, Chao et al., J. Mater. Chem. C, 3, 6307-6313, 2015

Li, Fang-Ze et al., Adv. Energy Mater., 3, 579-583, 2013

Figure 1
Surmofs and Cncs As Novel Tuneable Materials for Optical, Photonic and Solar Energy Materials
Authors: Redel Engelbert
Published: February 2020

Here, I will present a particularly interesting class of surface-anchored (metal-organic frameworks and coordination network compounds) materials SURMOFs and CNCs for the fabrication e.g. of 1D (Photonic Band Gap) PBG materials [1] as optical sensors, low-k dielectric thin films [2], optoelectronic/ electrochromic switchable coatings/devices [3] PV devices [4] or as future artificial Light-Harnessing (LH) antenna array assemblies as well as novel hybrid-photocatalyst.[5]

Since these materials are highly porous and the size of their pores are highly adjustable, they can be further functionalized (e.g. with different metal/oxo connectors or clusters linked with various organic linkers) e.g. in order to specifically bind target analytes (optical sensing), to electrically load and unload small ions (optoelectronic applications) as well as to act as photon traps, which are able to efficiently absorb, transport and harness light energy over an artificial LH antenna array.                                       

In addition, the RI (Refractive Index) as well as the optical properties of SURMOF and CNC materials can be tailored – a fact which makes these materials ideally suited for photonic, optical, optoelectronic, light-harnessing as well as for future solar energy systems like photocatalytic and PV applications.

Keywords: SURMOFs, porous  thin films, artificial light harnessing, optics and photonics, PV applications, photocatalysis.

References:

[1] J. Liu, E. Redel, S. Walheim, Z. Wang, V. Oberst, J. Liu, S. Heissler, A. Welle, M. Moosmann, T. Scherer, M. Bruns, H. Gliemann, Ch. Wöll Chemistry of  Materials (ACS)
2015,
27, 1991. 

[2] E. Redel, Z. Wang, S. Walheim, J. Liu, H. Gliemann, Ch. Wӧll, App. Physics Lett.
2013
, 103, 091903

[3] J. Liu, W. Zhou, S. Walheim, Z. Wang, P. Lindemann, S. Heissler, J. Liu, P. G. Weidler, T. Schimmel, Ch. Wöll, E. Redel Optics Express (OSA)
2015, 23, 13725.

[4] J. Liu, W. Zhou, J. Liu, I. Howard, G. Kilibarda, S. Schlabach, D. Couprey, M. Addicoat, S. Yoneda, Y. Tsutsui, T. Sakurai, S. Seki, Z. Wang, P. Lindemann, E. Redel, T. Heine, C. Wöll

*VIP ≡ Very Important Paper (Angewandte Front Cover Issue 2015-54/25) Angewandte Chemie International Edition
(Wiley-VCH)
2015, 54, 7441.

[5] W. Guo, Z. Chen, C. Yang, T. Neumann, C. Kuebel, W. Wenzel, A. Welle, W. Pfleging, O. Shekhah, C. Wöll and E. Redel, Nanoscale (RSC) 
2016, 8, 6468.
Resistance Switching in Individual Hydrogen Silsesquioxane (HSQ) Nanopillars
Authors: Ng Wing Hung , Buckwell Mark , Mehonic Adnan , Kenyon Anthony Joseph
Published: February 2020

We demonstrate resistance switching in individual 100nm-diameter hydrogen silsesquioxane (HSQ) nanopillars. HSQ is commonly used as an insulating material and an electron beam resist in the electronics industry, as it forms silicon oxide upon exposure to an electron beam. In this paper, we present our recent work on resistance switching in HSQ.

Our metal-insulator-metal (MIM) type devices consist of titanium and molybdenum top and bottom contacts, respectively, sandwiching a 30 nm HSQ thin film applied using standard spin coating techniques. Ti/HSQ nanopillars were fabricated from this sandwich structure using electron beam lithography and reactive ion etching. The fabricated nanopillars had typical diameters and heights of 100 nm and 110 nm, respectively, with a centre-to-centre spacing of 180 nm. In order to verify the composition of the HSQ thin film, X-ray photoelectron spectroscopy (XPS) was carried out. Results showed an Si4+ peak at 104 eV, which suggests the film is SiO2-like.

The ability to fabricate nanometre-scale resistive memory (ReRAM) devices is of interest both to provide a fundamental understanding of switching mechanisms and ultimate scaling limits, and also to precisely define the position of conductive filaments in devices.

We characterised and switched our nanopillar ReRAM structures using conductive atomic force microscopy (CAFM). We scanned a 1 µm by 1 µm area with a tip voltage of 10 V to modify the conductivity of the nanopillars. Followed by scanning the same area with 0 V bias and 2 V bias to map the conductivity. With a 2 V bias scan, some nanopillars showed an increase of conductivity (Figure 1), whereas with a 0 V bias scan, all the nanopillars remain insulating. This indicates that individual nanopillars exhibit resistance switching, and we could address single nanopillars as switchable elements in a ReRAM array.

Figure 1
Probing the Growth Mechanisms of Vertical-Stacked and Lateral-Grown MoS2 Few Layers
Authors: Chung Ya-Ting , Lu Ming-Yen , Wang Hsiang-Chen
Published: February 2020

Transition metal dichalcogenides (TMDCs) are layered materials with strong in-plane bonding and weak out-of-plane interactions enabling growth into two-dimensional (2D) layers of single unit cell thickness. The physical properties of TMDs are strongly dependent on their thickness. For example, there is an indirect to direct band gap transition from multilayer to monolayer MoS2. Two dimensional materials with a monolayer of atoms represent an ultimate control of material dimension in the vertical direction. In the present study, molybdenum disulfide (MoS2) monolayers were firstly grown on SiO2 substrate by means of chemical vapor deposition (CVD) method. By controlling the growth parameters of sequential growth, the vertical-stacked and lateral-grown MoS2 few layers can be achieved. An alumina boat containing S powder located forward the furnace and another alumina boat with MoO3 powder located at the center of the heating zone. Be 300 nm SiO2/Si substrate were placed behind MoO3 powder. Figs. 1 (a) and (b) show the optical microscopy (OM) images of MoS2 flakes grown with different gas flow and modulation of distance between source and substrate. The image contrast from OM, Raman spectroscopy and photoluminescence were used to characterize the samples. Moreover, the growth mechanisms are discussed in detail in this work.

Figure 1
High-Performance Photodetectors Using Transition Metal Dichalcogenide (TMD)-based Hybrid Structures
Authors: Jo Seo-Hyeon , Park Jin-Hong
Published: February 2020

Since the era of graphene, atomically thin transition metal dichalcogenides (TMDs) with a two-dimensional (2D) semiconducting layered structure have recently received increasing attention as suitable materials for post-silicon electronics and optoelectronics due to their exceptional electrical, mechanical, and optical properties. Particularly, TMDs present different energy band gaps depending on the type of TMDs and also exhibit strong optical absorption and ultrafast charge transfer, thereby providing many opportunities for researches in various optoelectronic devices, including photodetectors, solar cells, and light-emitting diodes. However, despite their superior optical properties, it is difficult for TMDs to absorb sufficient light due to their atomically thin body thickness, consequently restricting the successful integration of TMD-based optoelectronic device applications. In this light, various studies have been performed to improve the characteristics of TMD-based optoelectronic devices (especially photodetectors) through their hybrid structure, by applying the doping[1] or absorbing[2] (with very high absorption rate) layers, or inserting a passivating[3] layer (with suppression of carrier scattering), eventually improving the collection of photo-generated carriers.

Here, we demonstrate a high-performance TMD-based (WSe2 and ReSe2) photodetectors with a very high photoresponsivity (1.27×106 A/W for WSe2 and 1.18×106 A/W for ReSe2) and fast temporal photoresponse (rising/decaying time: 2.8/20.8 ms for WSe2 and 58/263 ms for ReSe2). This high-performance was accomplished by (i) applying a triphenylphosphine (PPh3)-based n-doping layer and (ii) inserting the passivating layers (hexagonal boron nitride (h-BN) or (3-aminopropyl)triethoxysilane (APTES) layers). The observed n-doping concentrations (Δn) were approximately 1.02 – 7.77×1011 cm-2 for TMD layers. By performing the PPh3-based n-doping process, the photoresponsivity of the TMD photodetectors increased (from 2.70×103 to 4.31×105 A/W for WSe2 and from 3.97×103 to 3.68×104 A/W for ReSe2). In particular, by additionally inserting a h-BN layer at the WSe2/SiO2 interface and an APTES layer at the ReSe2/SiO2 interface, we eventually obtained a very high photoresponsivity of 1.27×106 A/W for WSe2 and 1.18×106 A/W for ReSe2 while maintaining the other performance parameters (photoresponse times and photodetection range).

[1] D.-H. Kang, J. Shim, S. K. Jang, J. Jeon, M. H. Jeon, G. Y. Yeom, W.-S. Jung, Y. H. Jang, S. Lee, J.-H. Park, ACS Nano
2015, 9, 1099.

[2] S. H. Yu, Y. Lee, S. K. Jang, J. Kang, J. Jeon, C. Lee, J. Y. Lee, H. Kim, E. Hwang, S. Lee, J. H. Cho, ACS Nano
2014, 8, 8285.

[3] S. Wang, X. Wang, J. H. Warner, ACS Nano
2015, 9, 5246.
Medical Implants from a Unique Technology Combining a Highly Flexible Integration of Passives with Outstanding Performances
Authors: Bunel Catherine
Published: February 2020

Many implantable medical devices such as pacemaker, cochlear implant have been developed and tremendously improved in battery power, functionality, electrical power consumption, system delivery, and wireless communication but there is still room for improvement and they are still facing challenges in size shrinkage and reliability. Many efforts have been engaged to miniaturize and to facilitate the implantation of the device in order to reduce the impact of the surgery. IPDiA technology is actively contributing to this progress by providing passive components such as capacitor arrays or RC networks, with a high level of miniaturization , very low profile , very low leakage current , and outstanding reliability. In this paper, the enablers such as design flexibility, co-integration, low leakage current, extended life time will be presented and illustrated by several examples of solutions. Firstly, the recent progress in the capacitor technology development will be presented , secondly the focus will be made on the key differentiators and finally some of the applications where this technology is inescapable will be depicted.
(Plenary) Doing More with Less: Challenges for Catalyst Layer Design
Authors: Putz Andreas Michael Vincent , Susac Darija , Berejnov Viatcheslav , Wu Juan , Hitchcock Adam P , Stumper Jürgen
Published: February 2020

Proton exchange membrane (PEM) fuel cells are being developed as alternative energy sources for both residential and automotive application. In order for this technology to become fully commercial, the reduction of cost and improvements in performance and durability of PEM fuel cells membrane electrode assemblies (MEAs) are still required. To address the requirement for further cost reduction the Pt loading of the cathode catalyst layer (CCL) needs to be reduced to 0.2- 0.1 mg/cm2 while maintaining high efficiency of Pt-utilization at high power densities. Consequently, it becomes increasingly important to not only develop new catalyst materials, but also optimize the 3D structural arrangement of the CCL components such as catalyst, ionomer and void space so that all critical functionalities can be achieved simultaneously and optimize PGM utilization. In general terms this entails to provide sites catalytically active for ORR, and to further provide transport to/these sites for the reactants O2, protons, electrons and products H2O and heat, respectively. In order to be able to design CCL structures that meet the performance and durability requirements, it is necessary to obtain a better understanding of structure versus performance relationships. This requires the capability to fabricate different CCL structures, to characterize the spatial distribution of all components within the catalyst layer1,2 (carbon, Pt, ionomer and void), to measure the physico-chemical properties (both ex-situ and in-situ) and finally to use these experimental data as inputs for the development a model based understanding of the relationship between CCL structure and CCL performance and durability3.

 

References

A. P. Hitchcock, V. Berejnov, V. Lee, D. Susac and J. Stumper, “In situ methods for analysis of polymer electrolyte membrane fuel cell materials by soft X-ray scanning transmission x-ray microscopy”, Microscopy & Microanalysis 20(S3) 1532 (2014)

V. Lee, V. Berejnov, M. West, S. Kundu, D. Susac, J. Stumper, R.T. Atanasoski, M. Debe and A.P. Hitchcock, “Scanning Transmission X-ray Microscopy of Nano Structured Thin Film Catalysts for Proton-Exchange-Membrane Fuel Cells” J. Power Sources 263 163 (2014)

S. G. Rinaldo, W. Lee, J Stumper, M. Eikerling: “Nonmonotonic dynamics in Lifshitz-Slyozov-Wagner theory: Ostwald ripening in nanoparticle catalysts” Physical Review E 86, 041601 (2012)
(Invited) Effect of Cationic Group Chemisorption on Hydrogen Oxidation Reaction
Authors: Kim Yu Seung , Chung Hoon T , Matanovic Ivana
Published: February 2020

Alkaline environment offers the increased electrocatalystic activity and stability of non-precious metal group catalysts for the oxygen reduction reaction. However, sluggish hydrogen oxidation reaction (HOR) activity of electrocatalysts under alkaline environment has remained an issue to overcome. In this presentation, we report the hydrogen oxidation inhibition by organic cation adsoprtion to expalin the low HOR activity of Pt based electrocatalyst. The HOR activity of Pt based electrocatalyst in several organic cationic solutions including tetramethylammonium, tetrabuthylammonium, and tetrabutylphosphonium is investigated using rotating disk electrodes. Time-dependent and potential driven adsorption behaviors of the cationic groups suggest that this adsorption has rather complex chemisorption nature rather than just simple adsorption. The new proposed inhibition mechanism may give useful insites on how to design ionomeric binders and electrocatalysts for advanced alkaline membrane fuel cells.
Design of Organic-Inorganic Hybrid Nanocatalysts to Enhance Catalytic Activity and Durability for Oxygen Reduction Reaction
Authors: Jung Namgee , Yoo Sung Jong , Kim Sung-Soo , Jeong Jong-Ryul
Published: February 2020

In Pt-transition metal (TM) alloy nanoparticles for proton exchange membrane fuel cells (PEMFCs), the TM surface can be easily oxidized by air, water, and acidic electrolytes. Accordingly, the electron transfer from the TM to Pt is retarded owing to the electronegative O species on the TM surface, and the dissolution of the surface TM oxide is accelerated during the fuel cell operation, which results in catalyst degradation. Therefore, we propose a novel hybrid catalyst concept that selectively modifies the surface Co atoms with N-containing polymers, resulting in highly active and durable PtCo nanoparticles useful for the oxygen reduction reaction (ORR). The N-containing polymer functionalized on carbon black selectively interacts with the Co precursor, resulting in Co-N bond formation on the PtCo nanoparticle surface. Electron transfer from Co to Pt in the PtCo nanoparticles is therefore enhanced by the increase in the difference in electronegativity between Pt and Co. In addition, the dissolution of Co and Pt is prevented by the selective passivation of surface Co atoms and the decrease in the O binding energy of surface Pt atoms, respectively. As a result, the activity and durability of organic-inorganic hybrid PtCo nanocatalysts for the ORR are significantly enhanced by the electronic ensemble effects.