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2012 MRS Spring Meeting

作者： Peng, Shuang Du, Wenjun Rakesh, Leela Mellinger, Axel Kaya, Tolga Department of Physics Central Michigan University Mount Pleasant MI 48859 United States Department of Chemistry Central Michigan University Mount Pleasant MI 48859 United States Science of Advanced Materials Program Central Michigan University Mount Pleasant MI 48859 United States Department of Mathematics Central Michigan University Mount Pleasant MI 48859 United States School of Engineering and Technology Central Michigan University Mount Pleasant MI 48859 United States

ISBN: (纸本)9781627482431

We proposed the use of Copper (Cu) and Zinc (Zn) nanoparticles as the electrodes for thin-film microbatteries in the applications of micro-scale sensors. Compared to the widely used lithium-based batteries, Cu and Zn nanoparticles are less expensive, less prone to oxidation (thus involving simpler fabrication steps) and flammability, safe to use, and only requires very simple fabrication processes. Even though the voltage output is inherently smaller (∼1V) than conventional lithium-based batteries, it is sufficient for low-voltage Integrated Circuits (IC) technologies such as 130 nm and 90 nm channel length transistor processes. Commercial paper will be used as the separator to demonstrate the battery capacity. Paper that acts as the separator is slurry-casted with nanoparticles (30-40 nm in size) on both sides. The thickness of the metal nanoparticles-coated thin films and the paper separator are 1 μm and 100 μm, respectively. The electrodes were developed to achieve high conductivity (lower than 1 (Ω·cm)-1) with smooth surface, good adhesion, and flexibility. The metal nanoparticles will be formulated to slurry solutions for screen printing or ink-jet printing for the battery fabrication. For fabrication purposes, the slurries viscosity is approximately in the range of 10-12 cPs at the operating temperature, a surface tension between 28-33 dynes/cm. During the fabrication process including printing/coating and sintering, reductive environment is required to minimize the oxidation. AFM (Atomic Force Microscopy) and EDS (Energy Dispersive Spectroscopy) results will be employed to demonstrate the surface morphology as well as the percentages of metal oxides. Batteries will be tested with and without an ionic liquid for comparison. Humidity effects on the battery performance will also be discussed. Different geometries that are designed to make the batteries with higher voltage or charge will be proposed. Characterization results will include the open-circuit voltage,

关键词： Metal nanoparticles

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Accumulation-Driven Surfactant-Free Synthesis of Architectured Immiscible Metallic Nanoalloys with Enhanced Catalysis

SSRN

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SSRN 2019年

作者： Rajeeva, Bharath Bangalore Kunal, Pranaw Kollipara, Pavana Siddhartha Acharya, Palash V. Joe, Minwoong Ide, Matthew S. Jarvis, Karalee Liu, Yuanyue Bahadur, Vaibhav Humphrey, Simon M. Zheng, Yuebing Materials Science and Engineering Program Texas Materials Institute University of Texas at Austin AustinTX78712 United States Department of Chemistry University of Texas at Austin AustinTX78712 United States Walker Department of Mechanical Engineering University of Texas at Austin AustinTX78712 United States School of Mechanical Engineering Sungkyunkwan University Gyeonggi-do Suwon16419 Korea Republic of ExxonMobil Research and Engineering Company AnnandaleNJ08801 United States Texas Materials Institute University of Texas at Austin AustinTX78712 United States

Accumulation-mediated chemical reactions are a ubiquitous phenomenon in nature. Herein, we explore microbubble-induced accumulation of precursor ions to achieve surfactant-free synthesis of immiscible metallic nanoalloys and to simultaneously pattern the nanoalloys into targeted architectures for their enhanced catalytic applications. We name our approach as a unified spatiotemporal synthesis and structuring (US3) strategy, wherein millisecond-scale accumulation of the precursor ions in a highly confined laser-mediated microbubble trap (MBT) drives ultra-fast alloy synthesis in sync with the structuring process. As a case-in-point, we employ US3 strategy for the in-situ surfactant-free synthesis and patterning of traditionally immiscible rhodium-gold (RhAu) nanoalloys. Stochastic random walk simulations justify the millisecond-scale accumulation process, leading to a 3-order reduction in synthesis time. The catalytic activity and structure-property relationship of the structured nanoalloys were evaluated using the reduction of p-nitrophenol with NaBH4. Our in-situ synthesis and structuring strategy can be translated for high-throughput production and screening of multi-metallic systems with tailored catalytic, opto-electronic, and magnetic functions. © 2019, The Authors. All rights reserved.

关键词： Gold alloys

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Machine-learned design principles for enhanced red emission from nitride quantum wells

arXiv

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arXiv 2024年

作者： Pant, Nick Armitage, Rob Kioupakis, Emmanouil Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Materials Science & Engineering University of Michigan Ann ArborMI48109 United States Lumileds LLC San JoseCA95131 United States

Significant effort has been devoted toward mitigating polarization fields in nitride LEDs, as they are viewed as detrimental to light emission, albeit with limited success for red emission. Here, we show that such fields can unusually enhance the optical oscillator strength of red-emitting nitride quantum wells. This insight is enabled by machine-learned models trained on multi-scale quantum-mechanical simulations, which allow for a global exploration of the quantum-well design space at greatly reduced computational cost. Larger polarization fields correlate with higher wave-function overlaps for red emission, a consequence of the quantum-confined Stark effect enabling thinner quantum wells. This finding has implications for designing efficient red nitride LEDs, which are crucial for miniaturizing polychromatic LED pixels to the micron scale for extended-reality and biomedical applications. More broadly, this work highlights the power of machine learning in accelerating the discovery of unconventional paradigms for semiconductor design. Copyright © 2024, The Authors. All rights reserved.

关键词： Semiconductor quantum wells

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Self-Powered, Flexible, and Instantly Dynamic Multi-Color Electroluminescence Device with Bi-Emissive Layers for Optical Communication

SSRN

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SSRN 2023年

作者： Sun, Junlu Liao, Juan Dong, Fuying Chang, Yu Chang, Shulong Mao, Xin Li, Na Li, Xi Wang, Yong Shang, Yuanyuan Wang, Bin Shan, Chong-Xin Dong, Lin Henan Key Laboratory of Diamond Optoelectronic Materials and Devices Key Laboratory of Materials Physics Ministry of Education School of Physics & Microelectronics Zhengzhou University 450052 China College of General Studies Shanxi Institute of Science and Technology 048000 China Department of Mechanical Engineering City University of Hong Kong China

Self-powered alternating current electroluminescence (ACEL) displays own distinctive preponderance in artificial electronic skins and information communication in the internet of things (IoT). However, their limited color options, i.e., monochrome or static multicolor, hinder their versatility. In this paper, we introduce an instantly dynamic multi-color display system that combines integrated bi-emissive layer ACEL with a dual-cells triboelectric nanogenerator (DC-TENG). Our bi-emissive ACEL device includes ZnS:Cu and ZnS:Mn phosphors blended in polydimethylsiloxane (PDMS) to achieve green and orange emissions, respectively. The DC-TENG consists of a polytetrafluoroetylene (PTFE) film and two copper tapes, generating an open-circuit voltage of ~270 V and a short-circuit current of ~2.5 μA, which is sufficient to power the bi-emissive layer ACEL device. By pressing the DC-TENG cell, the self-powered display system instantly renders green, orange and warm white emissions, making these dynamic multi-color responses useful as information units in the IoT. The self-powered optical communication system is demonstrated by transmitting the word "CHINA". Our study may provide a new approach for developing self-powered multi-color display systems and expands their potential applications in information communication for the IoT. © 2023, The Authors. All rights reserved.

关键词： Silicones

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Developments in the utilization of heterogeneous catalysts for biodiesel generation: An update on recent advancements

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Journal of the Taiwan Institute of Chemical Engineers 2024年

作者： Parameshwar, Sai Agnihotri, Mayank Bhan, Uday Nangan, Senthilkumar Verma, Deepak Rajendran, Saravanan Jain, Siddharth Department of Petroleum Engineering and Earth Sciences UPES Dehradun248007 India Metallurgy and Materials Science Research Institute Chulalongkorn University Bangkok10330 Thailand International Graduate Program of Nanoscience and Technology Chulalongkorn University Bangkok10330 Thailand Instituto de Alta Investigacion Universidad de Tarapacá Arica1000000 Chile Department of Mechanical Engineering UPES Dehradun248007 India

Background: Biodiesel is one of the ecofriendly energy sources that can be generated from edible, non-edible, waste, and algae feedstocks. Over time, the utilization of different kinds of heterogeneous catalysts has been proven critical in the manufacture of biodiesel from diverse feedstocks. They exhibit better reusability and easier separation compared to the homogenous catalysts. Methods: In this work, the advances in the use of heterogeneous catalysts for biodiesel production from 2018 to 2024 have been evaluated. The process parameters like alcohol to oil molar ratio (M/O), catalyst concentration (%), reaction time and reaction temperature (RT), reusability of the catalyst, etc. are evaluated. The catalysts derived from waste materials through the calcination process are an efficient and cost-effective substitute for conventional catalysts. Nanomaterials, due to their small size and higher aspect ratio, provide very high efficiency and reusability in catalytic reactions. Significant findings: The heterogeneous catalysts are also found to be highly reusable for multiple cycles and the leaching of active sites, clogging of pore spaces of catalyst, etc. are the major causes of catalyst deactivation. Magnetic heterogeneous catalysts have shown good biodiesel yields and high reusability. Also, naturally occurring calcium oxide and potassium compounds present in waste derived catalysts helped to give high biodiesel yields. The future direction in the path of development of heterogeneous catalysts from cheap, abundant, and environmentally benign materials. The synthesis of heterogeneous catalysts from waste materials addresses the issue of waste disposal and converting solid waste to value-added catalysts. The life cycle assessment studies, encompassing heterogeneous catalyst synthesis, feedstock oil extraction, biodiesel production, and fuel combustion may give valuable input on the environmental impact of the entire process. © 2024

关键词： Potassium compounds

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Valley lifetimes of conduction band electrons in monolayer WSe2

arXiv

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arXiv 2020年

作者： Ersfeld, Manfred Volmer, Frank Rathmann, Lars Kotewitz, Luca Heithoff, Maximilian Lohmann, Mark Yang, Bowen Watanabe, Kenji Taniguchi, Takashi Bartels, Ludwig Shi, Jing Stampfer, Christoph Beschoten, Bernd 2nd Institute of Physics JARA-FIT RWTH Aachen University Aachen52074 Germany Department of Physics and Astronomy University of California RiversideCA92521 United States Department of Chemistry and Materials Science & Engineering Program University of California RiversideCA92521 United States Research Center for Functional Materials National Institute for Materials Science 1-1 Namiki Tsukuba Ibaraki305-0044 Japan International Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba Ibaraki305-0044 Japan Forschungszentrum Jülich Jülich52425 Germany

One of the main tasks in the investigation of 2-dimensional transition metal dichalcogenides is the determination of valley lifetimes. In this work, we combine time-resolved Kerr rotation with electrical transport measurements to explore the gate-dependent valley lifetimes of free conduction band electrons of monolayer WSe2. When tuning the Fermi energy into the conduction band we observe a strong decrease of the respective valley lifetimes which is consistent with both spin-orbit and electron-phonon scattering. We explain the formation of a valley polarization by the scattering of optically excited valley polarized bright trions into dark states by intervalley scattering. Furthermore, we show that the conventional time-resolved Kerr rotation measurement scheme has to be modified to account for photo-induced gate screening effects. Disregarding this adaptation can lead to erroneous conclusions drawn from gate-dependent optical measurements and can completely mask the true gate-dependent valley dynamics. Copyright © 2020, The Authors. All rights reserved.

关键词： Landforms

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Magnetic and Electric Behavior of Spike- and Petal-Like Nanoscaled Cu:Zno Superstructures Diluted Magnetic Semiconductors

SSRN

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SSRN 2022年

作者： Gunnewiek, Rodolfo Foster Klein Perdomo, Claudia P.F. Almeida, Diógenes F. Cancellieri, Igor C. Garcia, Leonardo A. Cardoso, André L.F. Federal University of São Carlos Graduate Program in Materials Science and Engineering Rod. Washington Luiz km 235 SP São Carlos13565-905 Brazil Federal University of Alfenas Graduate Program in Materials Science and Engineering Rod. José Aurélio Vilela BR 267 Km 533 11999 MG Poços de Caldas37715-400 Brazil Federal University of Alfenas Institute of Science and Technology Rod. José Aurélio Vilela BR 267 Km 533 11999 MG Poços de Caldas37715-400. Brazil

Room temperature ferromagnetism (RTFM) is the main condition for searching for materials to be applied in spintronics. Beyond the candidates, the diluted magnetic semiconductors (DMS) are potential materials for such application. The introduction of a foreign transition metal ion in the semiconductor lattice may lead to the RTFM, where the intrinsic ferromagnetism developed by a nonmagnetic ion is preferable for spintronics application. In this work, single-phase Cu-substituted zinc oxide was synthesized by a fast polymeric precursor method, providing nanocrystallites from 4 to 11 nm. Copper hindered grain growth, even for high Cu concentrations. The crystallites assembled to superstructures with petal and spike-like morphologies, following an unconventional crystallization. The texturization observed during the crystallization led to the development of unexpected weak RTFM. The number of oxygen vacancies is too small to promote the RTFM since few atoms of copper find attached to the vacancies. Probably the RTFM arises from overlapped spin-split bound magnetic polarons (BMP) due to the interaction of the hybridized O 2p and localized unoccupied twofold t2 subband of Cu 3d states. Although the sintering of pure and Cu-doped ZnO particles was equivalent, the electrical properties diverged. The copper insertion enhanced the resistivity and the non-linearity coefficient reached values higher than the unity. This is maybe due to the presence of copper at the grain boundaries forming a Schottky barrier. Neither the non-ohmic electrical behavior nor the RTFM from nanostructured superstructures was ever reported before. © 2022, The Authors. All rights reserved.

关键词： II-VI semiconductors

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Low-Density Coalti-B2 Strengthened Al-Co-Cr-Mo-Ti Bcc Refractory High-Entropy Superalloy Designed with the Assistance of High-Throughput Calphad Method

SSRN

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SSRN 2023年

作者： Yen, Shao-Yu Hideyuki, Murakami Lin, Shih-Kang Department of Materials Science and Engineering National Cheng Kung University Tainan70101 Taiwan School of Advanced Science and Engineering Research Center National Cheng Kung University Tainan70101 Taiwan Program on Smart and Sustainable Manufacturing Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan70101 Taiwan Core Facility Center National Cheng Kung University Tainan70101 Taiwan

Superalloys are widely used in the power plants and turbine engines due to the superior mechanical performance at elevated temperatures and oxidation resistance in crucial environments. To enhance the currently commercial Ni-based superalloys, refractory elements are desired candidates for novel alloy development due to their ultrahigh melting points. In the past decade, refractory high-entropy superalloys (RSAs), which are the multi-principal refractory element-based alloys with the microstructure of ordered body-centered cubic (bcc) (B2) precipitates coherently embedded in the disordered bcc (A2) matrix, have attracted great attentions. However, most reported RSAs show the reversed microstructure of the continuous B2 phase with the discrete A2 phase forming via the spinodal decomposition, which have poor thermal stability at elevated temperatures. Herein we designed a coherent precipitate-strengthened Al-Co-Cr-Mo-Ti RSA with the assistance of high-throughput CALPHAD (HT-CALPHAD) calculation. Pandat software with PanHEA 2021 database were used in searching desired compositions. The alloy was fabricated by vacuum arc melting (VAM) and characterized with X-ray fluorescence spectroscopy (XRF), differential thermal analysis (DTA), X-ray diffractometry (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The desired microstructure of CoAlTi-B2 homogeneously dispersed in the A2 matrix was obtained, resulting in the high hardness. The coherent bcc/B2 RSA with high hardness-to-density ratio is developed. © 2023, The Authors. All rights reserved.

关键词： Microstructure

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An Innovative Real-Time Cell Viability Analysis: A Cutting-Edge Flexible Bioimpedance Sensor

SSRN

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SSRN 2023年

作者： Chou, Hsin-Yu Ching, Congo Tak-Shing Huang, Hui-Xuan Phan, Thien Luan Wang, Hui-Min David Department of Materials Science and Engineering National Chung Hsing University Taichung40227 Taiwan Ph.D. Program in Tissue Engineering and Regenerative Medicine National Chung Hsing University Taichung402 Taiwan Graduate Institute of Biomedical Engineering National Chung Hsing University Taichung40227 Taiwan Department of Electrical Engineering National Chi Nan University Nantou54561 Taiwan Department of Physic and Electronic Engineering Faculty of Physic and Engineering Physic Vietnam National University Ho Chi Minh City University of Science Viet Nam Graduate Institute of Medicine College of Medicine Kaohsiung Medical University Kaohsiung807 Taiwan Department of Medical Laboratory Science and Biotechnology China Medical University Taichung City404 Taiwan

There are many compounds to be used to treat cancer but still only 20% of proposed anticancer agents have been commercialized after clinical trials due to serious side effects and unsatisfactory results. To screen potential drugs precisely and quickly, this study develops a flexible bioimpedance sensor. The sensor is positive to detect the half maximal inhibitory concentration (IC50) of drugs real-time by analyzing phase angle changes during cell mortality. The best results are achieved using a probe separation of A12B34 at logarithmic frequencies of 163 Hz and 77.87 kHz. At these two frequencies, there is a linear relationship with the phase angle at 0% and 50% of the dead cells. Dividing the phase angle at the two frequencies shows a 17.98% change in the phase angle, which allows self-correction and insensitivity to the number of cells. A custom phase angle measurement device is developed for detection at 163 Hz and 77.87 kHz, respectively. This study develops a novel sensor that is precise, fast and allows high throughput analysis to detect the inhibition of cancer in real-time. This sensor is an alternative to traditional chemical detection methods because it is faster, cheaper and more accurate. © 2023, The Authors. All rights reserved.

关键词： Chemical detection

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Aluminum Activation in Ionic Liquids

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ECS Meeting Abstracts 2015年第2期MA2015-03卷

作者： Boris Shvartsev Danny Gelman Itay Lasman Ingo Krossing Franziska Scholz Yair Ein-Eli Materials Science and Engineering Technion The Grand Technion Energy Program (GTEP) Technion Materials Science and Engineering Technion Universität Freiburg The Grand Technion Energy Program (GTEP) Technion

Aluminum (Al) is the third most abundant element (after oxygen and silicon) and the most abundant metal in Earth's crust. Al is quite remarkable as it holds a low density and it has the ability to resist corrosion due to surface passivation. This passivation layer protects Al from corrosion in a relatively wide range of pH and potentials. Nevertheless, in aqueous media, the layer is vulnerable in both highly acidic and basic environments, leading to rapid corrosion reactions. As an anodic material, Al has a theoretical gravimetric capacity of 2.98 Ah/gr and its volumetric capacity is as high as 8.1 Ah/cm3. For the sake of comparison, Li metal holds capacities of 3.86 Ah/g and 2.06 Ah/cm3, respectively. In non-aqueous media electrochemical dissolution of Al is partly hampered due to inefficient and thus insufficient passivation layer removal prior to any current application. Similar issues pertain when the non- aqueous solutions employed are Room Temperature Ionic Liquids (RTIL). In the present work an activation of Al was studied in EMIm(HF)2.3F RTIL. For this specific electrolyte it was already established that electrochemical dissolution of Al occurs, in considerable rates, sufficient for application in Al-Air batteries [1]. The alteration of the surface, as detected by FTIR, XPS and STEM, suggests on the formation of passivating Al-O-F compounds on the surface, instead of native oxide passivation. The source of this specific activation is established in this work, and the surface of Al prior to and following activation was identified. The applied methodology was also used for identification and study of Al activation in other family of RTILs. The preliminary results of this specific electrochemical system will be also presented. [1] D. Gelman, B. Shvartsev, Y. Ein-Eli, J. Mater. Chem. A. 2.47 (2014) 20237-20242.

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