bluuebunny/crossref_metadata_2025_split huggingface dataset:
Long-Term Cycling of Quinone Flow Batteries Using a Crossover Balancing Strategy
Authors: Kwabi David , Goulet Marc-Antoni , Gerhardt Michael R. , Aziz Michael J. 
Published: February 2020

Quinone-based redox flow batteries (RFBs) have comparable performance to all-vanadium RFBs but with reactants composed of earth-abundant elements, and hold promise for safe, cost-effective, large-scale energy storage. One of the major obstacles to their practical implementation is capacity fade during cycling, which is faster than that observed in all-vanadium systems (65-70% capacity retention after 10,000 cycles) [1]. Unlike in all-vanadium RFBs, the crossover of active species across the membrane leads to capacity loss that is not readily recovered with a simple rebalancing method. We present a study of a strategy for alleviating crossover-induced capacity loss, in which the flux of electroactive species across the membrane is balanced by an opposite flux of the same species in the complementary redox state. A model for balanced species flux across the membrane is developed and implemented in a quinone-based battery with a perfluorinated membrane. Its application results in a replenishment of capacity in the capacity-limiting side of the battery and reduces capacity loss to < 0.02%/cycle over hundreds of cycles at the time this abstract is being written. Criteria for extending this approach to other redox flow battery chemistries, and for enabling the use of inexpensive separators will be discussed.
[1] B. Dunn, H. Kamath, and J.-M. Tarascon, Science, 334 (2011).
Figure 1. Computed fluxes of bromine and bromide ions across a Nafion membrane as a function of state-of-charge (SOC). At 50% SOC, fluxes across the membrane are balanced.

Figure 1
Investigation of Solid Oxide Fuel Cell Anodes, Cathodes and Electrolytes with X-Ray Scattering and Spectroscopy
Authors: Braun Artur , Ilavsky Jan , Allen Andrew J. , Jemian Pete R. 
Published: February 2020

Solid oxide fuel cells (SOFC) are solid state electrochemical devices which operate at high temperatures up to 1000°C. Their components, particularly cathode and anode are structurally and chemically very complex. Specifically the porosity and internal surface area is a functionality per se and needs to be optimized so as to warrant optimum electrochemical conversion of fuel to electricity with a long service live. The assessment of the pore space is therefore instrumental for the functionality assessment. In contrast, the solid electrolyte shall have little or no porosity so as to present a good barrier to parasitic gas diffusion from anode to cathode, and vice versa. Of importance is ultimately the size of the electrochemical active interface. Traditionally, optical and electron microscopy imaging methods have been employed for the assessment of the pore space of such electrode assemblies. More recently, focussed ion beam tomography methods have been applied with success.
We provide an alternative method which requires no image analysis methods and which has a very high spatial resolution and element specific sensitivity. The method of choice is small angle scattering, which we have employed on a set of industry grade SOFC assemblies which were taken from stacks that had been run with sulfur ruch and sulfur depleted fuel, compared against the pristine electrodes. We present a detailed qualitative and quantitative assessment which is based on the chemical contrast variation and enhancement by using synchrotron radiation with tunable X-ray energy (anomalous small angle X-ray scattering).
With the data which obtained we are able to sketch a sulfur poisoning degradation model for the electrochemical interface (triple phase boundary) of the SOFC.
[1] A. J. Allen, J. Ilavsky, P. R. Jemian, A. Braun, Evolution of electrochemical interfaces in solid oxide fuel cells (SOFC): a Ni and Zr resonant anomalous ultra-small-angle X-ray scattering study with elemental and spatial resolution across the cell assembly, RSC Adv., 2014, 4, 4676-4690.
Pulse Plating of Copper from Deep Eutectic Solvents
Authors: Green Todd , Su Xiaomeng , Roy Sudipta 
Published: February 2020

In recent years there has been considerable interest in the deposition of metals, alloys and semiconductors from ionic liquids (ILs). These melts possess a number of advantages over traditional aqueous solutions, especially for the deposition of reactive metals and where the current efficiency of the process is inherently low. Deep eutectic solvents (DES) are a new class ionic liquids which possess low toxicity, low cost, and relatively good electrochemical characteristics. They have been used to deposit a wide range of materials and, unlike traditional ILs, it is often possible to obtain acceptable deposit characteristics in the presence of significant amounts of water contamination. This makes them particularly suitable for industrial-scale plating. Until now, most studies employing ILs or DES have concentrated on DC plating and there have been relatively few reports of electrodeposition under pulse conditions.
Ionic liquids have differing characteristics to aqueous solutions, particularly in terms of their double layer structure, mass transport properties, kinetics and conductivity. These differences indicate that pulse parameters developed for aqueous systems are unlikely to be optimal for deposition from ILs. For example, the very low diffusivity of the depositing species indicates that the DC and pulse limiting current are expected to be substantially lower compared to aqueous solutions. In this paper we will examine some of the constraints placed on the selection of pulse parameters dictated by the unusual properties of ionic liquids.
As an example of a ‘model’ system we will examine copper deposition from a deep eutectic solvent (DES) comprising ethylene glycol and choline chloride. After selection of appropriate pulse parameters some preliminary results obtained for copper electrodeposition will be reported. Of particular importance is the presence of a corrosion reaction in the off-time which puts additional constraints on the choice of pulse parameters.
(Electronics and Photonics Division Award Address) Compound Semiconductor Science and Technology: A Retrospective
Authors: Buckley D. Noel 
Published: February 2020

The very first State-of-the Art Program on Compound Semiconductors (SOTAPOCS I) was called to order at the 166thMeeting of The Electrochemical Society in New Orleans in the Fall of 1984. The first lightwave transmission system was then less than 4 years old and the first commercial cell phone was less than 3 years old. In fact, CW operation of a semiconductor laser at room temperature had been achieved less than 15 years before and even the transistor was still relatively young at 37 years. Our world has changed dramatically in the intervening years and compound semiconductors have played a vital role in the technologies that brought about that change. This talk will look back on some of the highlights and milestones in the development of compound semiconductors, recall some of the events along the way, and reflect on the key role played by The Electrochemical Society.
(Invited) Latest Status of Semiconductor Electrodeposition
Authors: Lincot Daniel 
Published: February 2020

The electrodeposition of semiconductors is a living field of electrodeposition technologies since many years, which remains highly challenging both at the fundamental level and at the application level. Well known examples are related to the electrodeposition of cadmium telluride thin films, or copper indium diselenide which went from fundamental studies to industrial applications in the field of photovoltaics. Semiconducting oxides like ZnO, copper oxides are other examples of successful developements. New routes are explored today for the electrodeposition of crystalline silicon thin films. Electrodeposition thus remains as a potential alternative or supplement to classical vapor phase or metallurgical routes for next generation technologies, as in photovoltaics, where low cost and large area processing capabilities are still required. In this presentation we will present the state of the art of the electrodeposition of semiconductors, both on the basis of a literature survey and also from direct studies carried out in our laboratory and research environment. We will focus on the design of electrodeposition conditions and concepts allowing, in the on going studies, to deposit either directly or indirectly semiconductor materials. Direct deposition allows the direct formation of the material while indirect formation involves the deposition of precursor materials (like metallic layers) followed by reactive post treatments. A special attention will be given to the deposition of semiconductors on semiconductors (including photodeposition) and to emerging field of the deposition on localised areas, like for microcells areas in new photovoltaics devices.
Solar-Driven Reduction of 1 atm CO2 to Formate at 10% Energy-Conversion Efficiency by Use of a TiO2-Protected III-V Tandem Photoanode in Conjunction with a Bipolar Membrane and a Pd/C Cathode Electrocatalyst
Authors: Zhou Xinghao , Liu Rui , Sun Ke , Chen Yikai , Verlage Erik , Francis Sonja A , Lewis Nathan S , Xiang Chengxiang("CX") 
Published: February 2020

A solar-driven CO2 reduction (CO2R) device that consists of a tandem InGaP/GaAs/TiO2/Ni photoanode in 1.0 M KOH for oxygen evolution reaction (OER), a Pd/C nanoparticles dark cathode in bicarbonate electrolyte at pH=8.0 for CO2R reaction and a bipolar membrane exhibited a solar-to-fuel (STF) conversion efficiency of 10%. The Pd/C nanoparticles showed low overpotential (< 100 mV) and high faradic efficiency (> 94%) for CO2 reduction to formate at 8.5 mA cm-2. The bipolar membrane exhibited low formate crossover and high transference number for proton and hydroxide at the steady-state pH gradient. The effective coupling between two different electrolytes that optimize the performance of CO2R reaction and OER provides new cell design spaces for efficient solar-fuel generation.
(Invited) Constructing Photocatalyst with Visible Light Response
Authors: Sun Zaicheng 
Published: February 2020

Solar-driven production of hydrogen (H2) from water splitting is considered as one of the promising ways to provide clean fuels. There are two critical issues for high efficient photocatalytic solar energy conversion. One is the extension of light absorption into visible light region, and the other is the enhancement of quantum efficiency at each wavelength. In the former case, the light absorption band strongly depends on the intrinsic band gap of the photocatalyst materials. Regarding to the latter case, enhancement of quantum efficiency has been attempted by improving the methods of modification and synthesis. In this presetation, defects, like oxygen vacancies, have been demonstrated to enhance photocatalytic activity for TiO2, SrTiO3 and other oxides due to excellent charge separation efficiency within their whole absorption band.[1-3] besides the surface defect, bulk defect like Ti3+ doped TiO2 can be treated as another kind of bulk defect also were invstigated.[4] Normally, these oxides only absorb UV light due to their large band gap. We also investigated the effect of defects on the photocatalytic activity of visible light photocatalyst, like sulfides, which have an extended visible light absorption from UV to visible light region (~ 550 nm).[5] The results indicate that the defects within a certain concentration can promote the charge separation and enhance the photocatalytic performance.
[1] Huaqiao Tan, Zhao Zhao, Mang Niu, Chengyu Mao, Dapeng Cao, Daojian Cheng, Pingyun Feng and Zaicheng Sun. Nanoscale, 2014, 2：10216-10223
[2] Huaqiao Tan, Zhao Zhao, Wan-bin Zhu, Eric N. Coker, Binsong Li, Min Zheng, Weixing Yu, Hongyou Fan, and Zaicheng Sun, ACS Appl. Mater. Interfaces:
2014, 6
：19184-19190
[3] Zhao Zhao, Huaqiao Tan, Haifeng Zhao, Yang Lv, Li-Jing Zhou, Yujiang Song and Zaicheng Sun, Chemical Communications, 2014, 50
： 2755-2757
[4] Zhao Zhao, Xiaoyan Zhang, Guoqiang Zhang, Zhenyu Liu, Dan Qu, Xiang Miao, Pingyun Feng, Zaicheng Sun. Nano Research: 2015, 8(12): 4061-4071
[5] Xiaoyan Zhang, Zhao Zhao, Wanwan Zhang, Guoqiang Zhang, Dan Qu, Xiang Miao, Shaorui Sun, Zaicheng Sun*. Solution Small:
2016 ,12: 10.1002/smll.201503067
(Invited) Atomic Layer Deposited Oxides on Silicon for Enhanced Solar Energy Conversion
Authors: Strandwitz Nicholas C 
Published: February 2020

Dielectric-semiconductor interfaces are integral to photovoltaic and photoelectrochemical systems. These interfaces provide electronic passivation, chemical protection, and can influence charge carrier collection at interfaces. Here we present two aspects of our work on dielectric-semiconductor interfaces: The impact of non-hydrolytic atomic layer deposition (NH ALD) chemistries and the role of fixed charge at metal-alumina-silicon tunnel contacts.
There is significant interest in minimizing oxidative damage to substrate semiconductors (e.g., Si) during ALD. Non-hydrolytic ALD chemistries utilize oxygen sources other than water or oxygen and have been shown inflict less oxidative damage to substrates. We directly compare NH and traditional ALD aluminum oxide chemistries and have found the NH ALD films have a larger fixed negative charge and larger interface trap state density. The understanding and control of semiconductor-dielectric interfaces is critical for controlling charge transport, possibly through leaky dielectrics, and for minimizing interface recombination.
Tunnel layer dielectrics (thickness < 2 nm) have been recently examined for protection and for increasing energy conversion figures of merit. In principle, fixed charge within such dielectrics can influence the electrostatic barrier in the semiconductor, which will have a direct impact on these figures of merit. We have examined alumina-silicon interfaces, in which the fixed charge can be tuned over a large range (+1E12 to -5E12 charges cm-2) by changing processing conditions. Based on an electrostatic model, these changes in fixed charge density should shift barrier heights by nearly 200 meV. In MIS stacks, we have found no evidence of changes in fixed charge in metallized, ultra-thin aluminum oxide layers. We will present several possibilities for why the fixed charge that is otherwise always found at these interfaces may be absent in metallized layers. Use of fixed charge to tune barrier heights could allow for large energy conversion figures of merit by simply tuning surface tunnel dielectrics in a manner similar to interfacial dipoles.
Enhanced Photoelectrochemical Efficiency of Self-Organized TiO2 Nanotube Layers Due to Secondary Materials
Authors: Macak Jan M. , Krbal Milos , Sopha Hanna , Prikryl Jan , Zazpe Raul , Ng Siowoon 
Published: February 2020

The self-organized TiO2 nanotube layers have attracted considerable scientific and technological interest over the past 10 years motivated for their possible range of applications including photo-catalysis, solar cells, hydrogen generation and biomedical uses [1]. The synthesis of 1D TiO2 nanotube structure is carried out by a conventional electrochemical anodization of valve Ti metal sheet. The main drawback of TiO2 is its applicability in the UV light (wavelengths < 390 nm). In order to enhance the efficiency, TiO2 has been doped by N [2] or C [3] o to shift its absorption into the visible light.
Except of doping, one of the major issues to extend the functional range of nanotubes is to coat homogenously tube interiors by a secondary material. It has been shown that additional ultrathin surface coating of TiO2 by secondary materials such as Al2O3 [4], ZnO [5] or MgO [6] annihilates electron traps at the TiO2 surface and thus increases the photogenerated concentration of charge carriers. Recently, it has been demonstrated that just a single cycle of Al2O3 [7] or ZnO [5] deposited by atomic layer deposition (ALD) efficiently improve charge transport properties of the heterostructure while gradual passivation appears with increasing ZnO thickness due to stronger band-bending [5].
The presentation will focus in detail on the coating of the nanotube arrays by secondary materials using ALD. The deposited materials influence strongly photo-electrochemical properties of nanotube films. Experimental details and some very recent photocatalytic [8] and sensing [9] results will be presented and discussed.
References:
[1] J. M. Macak et al., Curr.
Opin. Solid State Mater.
Sci. 1-2 (2007) 3.
[2] C. Burda et al., Nano Lett. 3 (2003) 1049.
[3] S. Sakthivel et al., Angew. Chem., Int. Ed. 42 (2003) 4908.
[4] R. Zazpe et al., Langmuir, in press, DOI:10.1021/acs.langmuir.6b03119.
[5] A. Ghobadi et al., Scientific Reports 6 (2016) 30587
[6] H. Park, et al., Journal of Electroceramics 23 (2009) 146.
[7] J-Y. Kim et al., Nanotechnology 25 (2014) 504003.
[8] M. Krbal et al., Ms submitted.

[9] S. Ng et al., Ms in preparation.
Argon Annealed ALD-ZrO2/SiON Gate Stack for Advanced CMOS Devices
Authors: Gupta Richa , Saikia Dulen , Vaid Rakesh 
Published: February 2020

Now-a-days, high-k dielectric materials are in demand as they not only inhibit direct tunneling but also ensures relatively thicker oxides. To replace SiO2 as gate dielectric, a number of high-k materials have been extensively studied such as aluminum oxide (Al2O3), zirconium dioxide (ZrO2), cerium oxide (CeO2), hafnium oxide (HfO2) and titanium dioxide (TiO2). Among them, ZrO2 is one of the most outstanding candidates due to its excellent chemical, physical and electrical properties such as good thermodynamic stability with silicon, high dielectric constant, high melting point, high refractive index, and sufficient band gap. Atomic layer deposition (ALD) method having the benefit of low temperature deposition and extremely precise thickness control has been utilized for the deposition of ZrO2 film. Additionally, the post deposition annealing (PDA) of ZrO2in argon (Ar) ambient has been performed along with Ti-Pt as bilayer metal gate.
Taking into consideration the state-of-the-art research progress, we report the fabrication of ultra-thin silicon oxynitride (SiON) as a sacrificial layer (SL) for n-Si/ALD-ZrO2 gate stackfollowed by post deposition annealing (PDA) of ZrO2 in argon (Ar) ambient. The surface roughness for the Ar annealed ZrO2 film measured using atomic force microscopy (AFM) was found to be 0.796 nm whereas the thicknesses of SiON SL ~ 5.34 nm and ZrO2 film ~ 11.63 nm were corroborated by field emission scanning electron microscope (FESEM) and spectroscopic ellipsometer (SE). Electrical characterizations such as capacitance voltage and current voltage measurements indicates the improved results for n-Si/ALD-ZrO2/Ti-Pt MOS capacitor in terms of various performance parameters such as dielectric constant (K), effective oxide thickness (EOT), leakage current density (J), effective oxide charge (Qeff) and series resistance (Rs) and their determined values are 26, 2.1 nm, 8.75 × 10-9 A/cm2, 0.42 × 1013 cm-2 and 4.54 KΩ respectively. The noble concept of SiON SL along with the PDA of ZrO2 in Ar ambient can enable the further scaling of n-Si/SiON/ZrO2 gate stack without the adverse effects of gate leakage current. Some of the important results obtained from the reported work have been exemplified in the figures below.

Figure 1
(Gordon E. Moore Medal for Outstanding Achievement in Solid State Science and Technology Address) Transient Polymers for Low-k Dielectrics and Vaporizing Devices
Authors: Kohl Paul A 
Published: February 2020

Dielectric materials provide critical functions throughout the interconnect hierarchy, including on-chip dielectrics, package substrates, and printed wiring boards. Transient polymers, those which vaporize on command, can be used to form ultra low-k dielectrics, such as porous materials or air-cavities. Transient polymers can also be used as coatings or structural materials in electronic packages and devices enabling the disappearance of the device when the collection, recovery or disposal of the device is difficult.
In this presentation, the motivation and opportunity for improved electronic materials will be presented. The nature of transient polymers will be described including their synthesis, physical properties, and chemical reactivity. Transient polymers can be decomposed into liquids or gases when exposed to a thermal, chemical or photo-chemical stimulus. Finally, several applications for transient polymers in the fabrication of unique electronic devices, structures or packages will be described.
GaN Based Hydrogen Sensor in Humid Ambient
Authors: Jung Sunwoo , Baik Kwang Hyeon , Jang Soohwan 
Published: February 2020

Hydrogen gas is a pollutant-free energy source that is closely related to industry and human life. Recently, intensive research has been conducted on hydrogen as an alternative fuel. Hydrogen gas is used in various fields such as refinery process, cooling system in nuclear power plant, semiconductor process and hydrogen fuel cell vehicle. However, hydrogen is the highly explosive gas with wide explosion range and low ignition energy. Thus, hydrogen gas detection in various conditions is very important for hydrogen-related industry. Especially for hydrogen sensors in hydrogen fuel cell vehicle, proper monitoring of the feed stream is critical to ensure highly efficient energy conversion. In this environment, accurate and reliable detection of hydrogen in highly humid ambient is vital. AlGaN/GaN high electron mobility transistor (HEMT) structure has high density and mobility carriers at 2 dimensional electron gas channel (2-DEG) induced by piezoelectric and spontaneous polarization of AlGaN and GaN interface, from which the drain current response can be amplified through a functionalized gate electrode. Most of GaN based hydrogen sensors including nanowires, Schottky diode, metal oxide semiconductor (MOS) diode, and AlGaN/GaN HEMT employ platinum thin films as catalytic active layer. Hydrogen molecules are dissociated on active Pt surface, influence the channel conductance or Schottky barrier height, and induce the current response.
In this work, AlGaN/GaN HEMT based hydrogen sensors incorporating nano-porous membrane was demonstrated. Platinum thin film serves as both Schottky contact and sensing material simultaneously. The device showed the excellent sensitivity for 500 ppm hydrogen even in 100% relative humidity. The nano-porous membrane coated on the sensor area effectively permits the approach of hydrogen gas molecules to sensing area while blocking water molecules which tend to cover the active sites of the sensor. The device showed reliable hydrogen gas sensing characteristics even after 25℃ ~ 100℃ heating cycle stress. This results support the potential use of AlGaN/GaN HEMT hydrogen sensor with nano-porous membrane in the applications of fuel cell vehicle.