bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optically Transparent Flexible IGZO TFTs Fabricated with a Selective Wet-Etch Process
Authors: Tari Alireza , Lee Czang-Ho , Wong William S. 
Published: February 2020

The emerging transparent thin-film transistor (TFTs) technology has recently received great attention in the active-matrix organic light-emitting diode (AMOLED) flexible displays. This TFT technology also has the potential to enable enhanced functionality in conventional large-area electronics applications ranging from smart windows and heads-up displays to flexible sensor arrays. During the past few years, amorphous transition-metal oxides have been suggested to be one of the best candidates in this application. Amorphous InGaZnO (IGZO) TFTs are the most promising transparent-metal oxide semiconductor due to its high optical transparency and field-effect mobility (μFE) in TFT devices compared to conventional amorphous silicon (a-Si:H). The amorphous structure is more suitable for large-area processes than other polycrystalline metal-oxide TFTs. These unique advantages have resulted in the rapid development of IGZO TFT technology. Given the relatively poor selectivity to common semiconductor etchants, IGZO TFTs are typically fabricated using lift-off processes to define the electrical contacts. However, the success of the emerging transition-metal oxide materials system for flexible electronics requires compatibility with conventional TFT microfabrication manufacturing processes.
Flexible IGZO TFTs having 85% optical transparency in the visible regime were fabricated on polyethylene napthalate substrates using a selective wet etching process to eliminate the need for lift-off processing. The devices were processed directly onto the plastic platform at a maximum temperature of 150°C. The TFT structure consisted of a sputtered 100 nm aluminum doped zinc oxide (AZO) gate electrode, a 300nm SiNx gate dielectric deposited using plasma enhanced chemical vapor deposition (PECVD) method at 150ºC, and a 50nm IGZO layer deposited using RF sputtering at room temperature. A 150 nm AZO source/drain (S/D) electrodes were deposited by using RF sputtering at 150ºC and patterned wet etching process in diluted HCl solution having a selectivity of 11 between AZO and IGZO. The channel width and length of the studied TFTs were 200 and 100 µm, respectively.
The fabricated TFTs exhibited a field-effect mobility of ~10 cm2/V.sec, threshold voltage of ~5.0 V, a sub-threshold swing of 0.8 V/decade, and an Ion/Ioff ratio of 107. No current crowding behavior was observed for the TFTs at the low drain-source voltage (VD) regime. The I-V characteristics showed excellent ohmic contacts can be fabricated using AZO S/D electrodes through a wet etching process and promises a more conventional approach to large-area flexible electronics fabrication. The highly selective etching process provides a means to fabricate IGZO based circuits with low processing complexity that will enable system-on-“plastic” integration of flexible transparent flexible displays. In addition, the effect of long-term electrical bias on the electrical stability of the devices will also be presented.
Electrodeposited Sb- Doped ZnO Nanorod Arrays and Electrical Characterization Based on Single Nanorod Field Effect Transistors
Authors: Liang Jin-Kun , Su Hai-Lin , Kuo Chun-Liang , Wu Yu-Cheng , Huang Jung-Chun Andrew 
Published: February 2020

Sb-doped ZnO nanorods were fabricated via electrochemical methods. SbCl3,
Zn(NO3)2 and hexamine mixed solution were used as a precursor. The morphology, composition
and crystallinity of nanorods were characterized using a field emission scanning electron microscope,
energy dispersive X-ray spectroscopy and X-ray diffraction, respectively. The transmitted spectrum
was used to investigate optical properties of Sb-doped ZnO arrays. Single Sb-doped ZnO nanorod field effect transistors were constructed via standard photolithography process.
The dependence of nanorod resistance on the temperature from 5K to 300K and the current
versus voltage curve of the field effect transistor at different temperature from 100K to 300K were measured.
The Sb-doped nanorod showed different electrical properties following the change of temperature.

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(Invited) The Joint Center for Energy Storage Research (JCESR): A New Paradigm for Energy Storage Research
Authors: Crabtree George 
Published: February 2020

The Joint Center for Energy Storage Research (JCESR) pursues high performance, low cost beyond lithium ion electricity storage that will transform transportation and the electricity grid. JCESR will leave three legacies:

a library of fundamental knowledge of the materials and phenomena of energy storage at the atomic and molecular level

two prototypes, one for the grid and one for transportation, that, when scaled to manufacturing will be able to deliver five times the energy density at one-fifth the cost

a new paradigm for battery R&D that combines discovery science, battery design, research prototyping and manufacturing collaboration in a single highly interactive organization, accelerates the pace of discovery and innovation and significantly shortens the time from discovery to commercialization.

An introduction to JCESR’s vision, mission and legacies will be followed by research highlights illustrating its advances in fundamental science and the promising pathways to transformational battery designs and prototypes.
This work was supported as part of the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences
(Invited) Techno-Economic Analysis of Batteries and Key Considerations for Performance Comparisons
Authors: Gallagher Kevin G. 
Published: February 2020

Energy storage and conversion technologies range from those currently in widespread application to those that exist mainly in the research laboratories around the world. Evaluating technologies against each other requires unbiased and defensible tools and metrics even within the same class of storage technology (e.g. transportation batteries). Techno-economic modeling is a powerful tool that can be used to compare both across platforms as well as within [1 ,2]. This talk will focus on electrochemical energy storage in the form of enclosed, hybrid, and flow batteries for both transportation and stationary applications. Key performance indicators will be discussed and values compared for existing technologies against promising new chemistries under development. The role of the analysis framework will be highlighted particularly in light of considering market size and maturity. Finally, comparison to other non-battery technologies will be presented.
[1] K. G. Gallagher, S. Goebel, T. Greszler, M. Mathias, W. Oelerich, D. Eroglu, V. Srinivasan “Quantifying the promise of lithium-air batteries for electric vehicles” Energy & Environmental Science, 7 (5), 1555 - 1563 (2014)
[2] R. M. Darling, K. G. Gallagher, J. Kowalski, S. Ha, F. Brushett “Pathways to low-cost electrochemical energy storage: a comparison of aqueous and nonaqueous flow batteries” Energy & Environmental Science, 7 (11), 3459 – 3477 (2014)
(Invited) Standardizing Experimental Methods and Metrics in the Field of Photoelectrochemical (PEC) Water Splitting
Authors: Chen Zhebo , Dinh Huyen N , Miller Eric Lars 
Published: February 2020

Photoelectrochemistry is a particularly rich field of study that combines principles and concepts from both semiconductor physics as well as electrochemistry. Although its intellectual depth provides incredible opportunities for technical development, it also presents a steep learning curve for scientists new to this field who wish to leverage PEC in their efforts to advance low-carbon energy conversion research. As a result, PEC studies are not always performed consistently from one laboratory to the next, limiting the ability to accurately compare results in the literature and amongst researchers. In order to address this challenge, the U.S. Department of Energy formed the PEC Standards Working Group to identify the most readily accessible experimental methodologies as well as the most meaningful metrics required to advance materials development. Herein, we discuss the path taken towards establishing benchmarks in PEC water splitting as well as the key concepts and methodologies identified as being the most pertinent within the field. These include various efficiency definitions in addition to techniques such as illuminated 3- and 2-electrode electrochemical measurements. Such measurements can elucidate important material properties including band structure and charge transport. Understanding the advantages and the limitations of these methods is a critical step towards enabling researchers to more accurately evaluate the performance capability of PEC devices and to advance progress in the field.

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(Invited) Fermentative Hydrogen Production from Biomass in the Cellulose-Degrading Bacterium Clostridium Thermocellum
Authors: Magnusson Lauren , Chou Katherine , Maness Pin-Ching 
Published: February 2020

Hydrogen can be produced from diverse energy sources, using a variety of process technologies. One promising route for biological hydrogen production is via the fermentation of renewable lignocellulosic biomass. However, due to its crystallinity, biomass has to undergo a thermochemical pretreatment step in order for microbes to ferment its cellulose and hemicellulose constituents. Clostridium thermocellum is a thermophilic (55 – 60oC) and anaerobic bacterium which displays one of the highest growth rates on cellulose. C. thermocellum is capable of simultaneous biomass hydrolysis and fermentation in one integrated step, which could be a potential cost saver. During cellulose fermentation, the bacterium produces hydrogen, ethanol, formate, lactate, acetate, and CO2. To reduce the cost of hydrogen production, we aim to overcome several technical barriers identified by the DOE Fuel Cell Technologies Office. To reduce the feedstock cost barrier, we optimized cellulose fermentation in bioreactors, operating in either batch or fed-batch mode. In the latter mode we tested parameters including hydraulic retention time, and amount and frequency of liquid replacement. To circumvent the low hydrogen molar yield barrier (mol H2/mol hexose), we conducted genetic engineering by redirecting metabolic pathways toward maximal hydrogen production lieu of reduced carbon byproducts. Lastly, a techno-economic analysis is underway to set the targets and to guide future research direction to deliver low cost hydrogen. This effort would rely on standardization of metrics in the fermentation technology to assess more accurately as to its economic viability.
Design and Cost Considerations of Solar-Fuel Devices
Authors: Modestino Miguel A. , Rodriguez Claudia A. , Psaltis Demetri , Moser Christophe 
Published: February 2020

Recent environmental concerns have led to an increased interest in the deployment of renewable energy technologies. Electrochemical energy conversion devices that can directly capture and store solar energy in the form of fuels are a promising alternative to increase the share of renewables in our current energy landscape. In order to deploy solar-fuel technologies in large scale, practical devices need to operate continuously and stably over long periods of times, need produce more energy over their lifetime than they require for their fabrication and need to generate fuels in an economically viable way. To this end, significant research efforts have been devoted towards the development of photoelectrochemical components that are able to spontaneously split water in the presence of solar irradiation. These efforts have resulted in major advances in the solar-fuels field over the past decade, while only limited attention has been given to understanding the factors that drive economically viable solar-fuel generators. In this presentation we will describe a system agnostic approach that allows for the understanding of economic factors behind the design of solar-hydrogen generators.(1) Using this framework, we evaluate the effects of the material selection for the light absorption and water splitting components on the cost of the generated fuel ($/Kg of H2). Furthermore, guidelines for optimal designs for solar water-splitting devices are formulated in order to minimize the cost of hydrogen production. The results presented here provide insights into engineering aspects related to device design and the use of light concentration components that, when optimized, can lead to costs below $2.90 per kilogram of hydrogen after compression and distribution (reaching comparable cost levels to hydrogen produced from fossil fuel). In order to achieve these low hydrogen production costs, optimized devices will need to be fabricated with water splitting components that are significantly smaller in area than light absorption units (by a factor 10-100’s). Moreover, the analysis demonstrates that in optimized devices the cost of hydrogen is primarily driven by the light-absorbing component while the material selection for the electrolysis components has minor effects. This suggests that the development of highly efficient and inexpensive photovoltaic components for solar water-splitting can greatly facilitate the implementation of the technology. The findings discussed here can help direct research and development efforts towards the fabrication of scalable solar-hydrogen generators that are cost competitive with commercial energy sources.
1. C. A. Rodriguez, M. A. Modestino, D. Psaltis, C. Moser, Design and cost considerations for practical solar-hydrogen generators. Energy & Environmental Science, (2014). DOI: 10.1039/c4ee01453g
(Invited) Enhanced Steam Electrolysis at Exsolution Titanates
Authors: Neagu Dragos , Tsekouras George , Shin Tae-Ho , Irvine John 
Published: February 2020

B-site doped, A-site deficient perovskite titanate oxides with formula (M = Ni2+ or Fe3+; x = 0.06; g = (4-n)x/2) were employed as solid oxide electrolysis cell (SOEC) cathodes for hydrogen production via high temperature steam electrolysis (HTSE) at 900 °C. A proportion of B-site dopants were exsolved at the surface in the form of metallic nanoparticles under SOEC operating (reducing) conditions, due in part to the inability of the host lattice to accommodate vacancies (introduced (d) oxygen vacancies () and fixed A-site () and inherent (g) oxygen vacancies) beyond a certain limit. The presence of electrocatalytically active Ni0 or Fe0 nanoparticles and higher concentrations dramatically lowered the activation barrier to steam electrolysis and led to sharp rises in oxide ion mobility compared to the parent material (x = 0). La0.4Sr0.4Ni0.06Ti0.94O2.94 demonstrated discontinuous temperature dependence possibly due to oxygen vacancy trapping at lower temperatures.
The Effect of Mixed-Conductivity on Electrolysis Cells Involving BaCexZr0.9-XY0.1O3-d (x = 0, 0.1 and 0.2) Protonic Ceramic Membrane
Authors: Babiniec Sean M , Dippon Michael , Ricote Sandrine , Sullivan Neal P 
Published: February 2020

Planar, fuel electrode-supported cells were fabricated utilizing a thin (~25 μm) BaCexZr0.9-xY0.1O3-δ electrolyte on a 1-mm-thick BCZY27/Ni fuel electrode [1]. Three electrolyte compositions were studied: x = 0, 0.1 and 0.2 referred to as BZY10, BCZY18 and BCZY27 respectively. Two different air electrodes were prepared: painted Au or a 40-μm-thick porous BCZY27 backbone infiltrated with La2NiO4+δ nano-particles as an electro-catalyst. As shown in Figure 1, which is an example of the cell microstructure for the infiltrated backbone, the adhesion between the electrolyte and the electrodes as well as the density of the electrolyte are satisfactory.
These devices were tested over a wide range of conditions. Both fuel-cell and electrolyser modes of operation were explored over a range of temperature spanning 550-750 °C. Flux of hydrogen was continuously monitored with a gas chromatograph and a mass spectrometer in parallel. Figure 2 displays the hydrogen fluxes in electrolysis operation measured with a BCZY27 electrolyte at 700 °C with 5% H2, 3% H2O (balance Ar) at the fuel electrode and 21%, 7% H2O (balance Ar) at the air electrode. The measured hydrogen fluxes are far below the Faradaic fluxes. The difference between the measured fluxes and the Faradaic fluxes increases with increasing current. Similar results were reported by Sakai et al. [2] and Matsumoto et al.[3].
Oxide ion conduction is negligible as no increase of steam content was measured at the fuel electrode. Therefore, the low Faradaic efficiency can only be compensated by an electronic leakage. This work draws a comparison of the hydrogen fluxes with the percentage of cerium in the BaCexZr0.9-xY0.1O3-δ membrane.

References:
1. S.M. Babiniec, S. Ricote, N.P. Sullivan, submitted to Journal of Power Sources
2. T. Sakai, S. Matsushita, H. Matsumoto, S. Okada, S. Hashimoto, T. Ishihara, Int. J. Hydrogen Energy 34 (2009) 59
3. H. Matsumoto, T. Sakai, Y. Okuyama, Pure Appl. Chem. 85 (2013) 427

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Steam Electrolysis By Proton-Conducting Solid Oxide Electrolysis Cells (SOECs)
Authors: Bi Lei , Traversa Enrico 
Published: February 2020

Solid oxide electrolysis cells (SOECs) are considered as an effective way of converting renewable energies to chemical energy in the form of hydrogen. Using this conversion as energy storage, we can solve the site-specific and intermittent problems for renewable energies, such as solar and wind energy. During the SOEC working condition, H2O is split into H2 and O2 by applying voltage. Compared with low temperature electrolysis cells, SOECs that work at high temperatures can save electricity with the compensation from heat sources [1]. However, conventional SOECs using oxygen-ion conducting electrolytes have several problems. First, the working temperature is quite high due to the use of yttria-stabilized zirconia (YSZ) as electrolyte, which possesses adequate conductivity only at high temperatures. Second, the produced H2 is mixed with H2O, needing further separation. Third, the Ni-based fuel electrode materials trend to be oxidized by H2O during operation. To solve these problems, proton-conducting oxides are proposed as alternative electrolytes that show several advantages and can avoid the mentioned problems occurring for conventional oxygen-ion SOECs [2]. However, current proton-conducting SOECs focus on the use of BaCeO3-based electrolytes, which have been demonstrated to be unstable in the presence of water. In this talk, chemically stable BaZrO3-based electrolyte material used for proton-conducting SOECs is presented. Proton-conducting SOECs with BaZrO3-based electrolyte show a good chemical stability, together with reasonable cell performance and a superior long-term stability. The possibility of applying proton-conducting SOECs for synthesizing CH4 by co-electrolyzing CO2 and H2O will be also discussed.

Reference

1. A. Hauch, S. D. Ebbesen, S. H. Jensen and M. Mogensen, J. Mater. Chem., 2008, 18, 2331-2340.
2. Lei Bi, Samir Boulfrad and Enrico Traversa, Chem. Soc. Rev., 2014, 43, 8255-8270.
Phase Dependent Selectivity of Electrochemical CO2 Conversion to Fuels on TiO2 nanoparticles
Authors: Wright Christopher J. , Sharma Pranav P. , Ke Fu-Sheng , Peterson Andrew A. , Zhou Xiao-Dong 
Published: February 2020

We report the activity and selectivity of electrochemical CO2 reduction to carbon monoxide and formate on rutile (110) and anatase (101) TiO2. Our studies show that the rutile TiO2 phase was found to be more selective, with Faradaic efficiencies of ~ 15% and ~ 18% for CO and formate, while the anatase efficiencies were less than ~2%. The phase dependent efficiency exhibited by the electrochemical reaction is opposite to previously reported photochemical CO2 reduction efficiency, which showed a greater activity from anatase TiO2. In order to evaluate the role of oxygen vacancy and Ti3+ sites in the catalytic activity XPS was performed on the catalysts after CO2 reduction. The XPS showed oxygen vacancies and Ti3+ defects in both the anatase and rutile phases. This implies that while the presence of surface defects may be necessary for the electro reduction of CO2 on TiO2 the efficiency determining property is the catalyst’s underlying atomic structure. Our recent results using DFT to elucidate a potential mechanism for this phenomenon, comparing the binding energies of CO2 reduction adsorbates on rutile and anatase TiO2, will also be discussed.
(Invited) Two-Dimensional Materials for Electrochemical Synthesis of Fuels
Authors: Wu Jingjie , Liu Mingjie , Hackenberg Ken , Liu Yuanyue , Yadav Ram Manohar , Sharma Pranav P. , Zhou Xiao-Dong , Wood Brandon , Yakobson Boris I. , Lou Jun , Ajayan Pulickel M 
Published: February 2020

The sustainable civilization and long-term economic development rely on the security of energy. The conversion of carbon dioxide into fuels or commodity chemicals, incorporated with intermittent renewable energy sources like solar and wind, is an attractive venture that could offer an alternative solution to both the contemporary energy crisis and environmental issues. The recycling of carbon dioxide together with water by utilizing renewable electricity in the low temperature electrolysis process provides a diversity of carbon-neutral fuel products depending on the catalyst system.The development of active and stable catalyst system with affordable cost for the low temperature electrolysis remains a major challenge. We developed carbon-based two dimensional materials as metal-free catalysts for efficient, selective and sustainable electroreduction of carbon dioxide into carbon monoxide.
Hydrogen is not only an ideal energy carrier, but also an important agent for many industrial chemical processes. The economical production of hydrogen from electrochemical water splitting is strongly dependent on the affordable catalysts with promising activity to replace platinum-group metals. Recently, layered molybdenum and tungsten have attracted substantial interest to catalyze hydrogen evolution reaction (HER) with their suitable differential free energies for intermediate adsorbed *H at the edge sites. We aim to develop a novel series of transition-metal dichalcogenides with surface activity for HER with a combination of theoretical prediction and experimental verification.