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arXiv 2024年

作者： Huang, Chen Department of Scientific Computing Materials Science and Engineering Program National High Magnetic Field Laboratory Florida State University TallahasseeFL32306 United States

Electronic structures are fully determined by the exchange-correlation (XC) potential. In this work, we develop a new method to construct reliable XC potentials by properly mixing the exact exchange and the local density approximation potentials in real space. The spatially dependent mixing parameter is derived based on the derivative discontinuity of electron density and is first-principle. We derived the equations for solving the mixing parameter and proposed an approximation to simplify these equations. Based on this approximation, this new method gives reasonable predictions for the ionization energies, fundamental gaps, and singlet-triplet energy differences for various molecular systems. The impact of the approximation on the constructed XC potentials is examined, and it is found that the quality of the XC potentials can be further improved by removing the approximation. This work demonstrates that the derivative discontinuity of electron density is a promising constraint for constructing high-quality XC potentials. © 2024, CC BY.

关键词： Local density approximation

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Correlation between Composition and Work Function Through Kelvin Probe Force Microscopy – Pure Magnesium Single Crystals

SSRN

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SSRN 2023年

作者： Türe, Yiğit Kaya, Ali Arslan Shin, Kwang Seon Turan, Servet Eskisehir Technical University Porsuk Vocational School Electronics and Automation Department Program of Mechatronics Eskisehir Turkey Mugla Sıtkı Kocman University Engineering Faculty Metallurgy and Materials Engineering Department Mugla Turkey Seoul National University Materials Science and Engineering Department Seoul Korea Republic of Eskisehir Technical University Engineering Faculty Materials Science and Engineering Department Eskisehir Turkey

The aim of this work was to investigate the feasibility of observing the effect of impurities in pure magnesium (Mg) on the work function (WF) measurements by using Kelvin Probe Force Microscopy (KPFM). In essence, the pure Mg samples used in this study can be regarded as extremely dilute solid solutions of Mg with some impurity atoms. This investigation further considers the measured WF differences within a crystal as figures that are directly affected by the free electron density distribution, which essentially refers to the nature of the interatomic bonding. A corollary of this view is that stacking fault energy (SFE) changes in a solid solution system can also be revealed via KPFM measurements, as SFE also depends on the free electron density distribution. Since the atomic density would affect the WF and SFE levels, the crystal orientations of the single crystal Mg samples had to be determined via electron diffraction patterns obtained via TEM. It has been shown that WF differences as measured via KPFM, offer a technique that can be at least qualitatively correlated with the interatomic bond strength levels, and therefore be also interpreted as an indicator of SFE levels. This practical measurement approach appears to be a reliable way of understanding the effect of individual elemental changes in multi-element solid-solution systems which currently do not lend themselves to computational techniques due to the number of elements involved. It should be borne in mind that the computed SFE values in the literature are not treated as absolute values but rather become useful when assessing the properties of alloys at a fundamental level, i.e., free electron density distributions. Therefore, it seems possible to use the principles of ‘electronic metallurgy’ in developing multi-element alloy systems. © 2023, The Authors. All rights reserved.

关键词： Single crystals

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Piezoelectricity of strain-induced overall water splitting of Ni(OH)2/MoS2 heterostructure

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Journal of materials Chemistry A 2023年第7期11卷 3481-3492页

作者： Le, Kim Tuyen Pham, Nguyet N. T. Liao, Yin-Song Ranjan, Ashok Lin, Hsun-Yen Chen, Po-Han Nguyen, Hoang Lu, Ming Yen Lee, Seung Geol Wu, Jyh Ming Department of Materials Science and Engineering National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan Department of Chemistry University of Science Vietnam National University Ho Chi Minh City Viet Nam School of Chemical Engineering Pusan National University 2 Busandaehak-ro 63 beon-gil Geumjeong-gu Busan46241 Korea Republic of Department of Organic Material Science and Engineering Pusan National University 2 Busandaehak-ro 63 beon-gil Geumjeong-gu Busan46241 Korea Republic of PhD Program in Prospective Functional Materials Industry National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan High Entropy Materials Center National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan Vietnam National University Ho Chi Minh City Linh Trung Ward Thu Duc City Ho Chi Minh City700000 Viet Nam

In this study, we synthesized several active sites of molybdenum disulfide (MoS2) nanoflowers (NFs) decorated with Ni(OH)2 nanoparticles (NPs) to form heterostructures. Our results revealed that Ni(OH)2/MoS2 NF heterostructures caused the splitting of water into hydrogen (H2) and oxygen (O2) gas. The Ni(OH)2/MoS2 NF interface exhibited strain-induced piezoelectric potential (piezopotential) that promoted charge separation, reducing the kinetic barrier in the water splitting process and promoting the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). In high-resolution transmission microscopy images, the measured lattice fringe d spacing was approximately 0.67 nm, which was higher than the reported value. The calculated tensile strain of Ni(OH)2/MoS2 NF heterostructures was approximately 3.5%. The findings based on density-functional theory and using the finite element method indicated that the interfacial piezopotential generated between Ni(OH)2 and MoS2 NFs enhanced charge transfer and electrochemical reactions. To obtain a current density up to 10 mA cm−2, we set the overpotential and Tafel slope of Ni(OH)2/MoS2 NF heterostructures at 155 mV and 62.1 mV dec−1 for the HER and 328 mV and 69.3 mV dec−1 for the OER, respectively. Moreover, a high Faraday efficiency (84.1%) was observed over 48 h, with no significant decline in the HER and OER. © 2023 The Royal Society of Chemistry.

关键词： Molybdenum disulfide

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Development and Evaluation of a PANI/PMMA Composite Gas Sensor for Acetone Detection in Breath

Development and Evaluation of a PANI/PMMA Composite Gas Sens...

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STEM Education Conference (iSTEM-Ed), International

作者： Natnaree Phukkaphan Chayanin Khunarak Teerakiat Kerdcharoen Faculty of Science Materials Science and Engineering Program and Center of Nanoscience and Nanotechnology Mahidol University Bangkok Thailand Department of Physics Faculty of Science Mahidol University and NANOTEC Center of Excellence at Mahidol University Bangkok Thailand

ISBN: (数字)9798350365979

ISBN: (纸本)9798350365986

In recent years, the development of sensors capable of detecting acetone levels has garnered attention in health monitoring and personalized medicine. Acetone in the body, a ketone body produced during metabolic processes, has emerged as a promising biomarker for various health conditions, including diabetes, obesity, and metabolic disorders. Its presence in exhaled breath offers a non-invasive means of assessing metabolic health, presenting a unique opportunity for continuous monitoring and early intervention. This research investigated the use of a PANI/PMMA polymer sensor array to measure acetone gas. Breath samples and standard substances (acetone, butyric acid) were collected using a hygienic mask and measured with an electronic nose device. The tests showed the sensor could classify between a blank mask, acetone, butyric acid, and breath odors.

关键词： Obesity Precision medicine Education Electronic noses Sensors Polymers Monitoring

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Optimizing Off-Axis Fields for Two-Axis Magnetometry with Point Defects

arXiv

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arXiv 2024年

作者： Beaver, N.M. Voce, N. Meisenheimer, P. Ramesh, R. Stevenson, P. Department of Physics Northeastern University BostonMA02115 United States Department of Materials Science and Engineering University of California BerkeleyCA94720 United States Department of Materials Science and NanoEngineering Rice University HoustonTX77251 United States Department of Physics and Astronomy Rice University HoustonTX77251 United States Department of Physics University of California BerkeleyCA94720 United States

Vector magnetometry is an essential tool in characterizing the distribution of currents and magnetization in a broad range of systems. Point defect sensors, like the nitrogen vacancy (NV) center in diamond, have demonstrated impressive sensitivity and spatial resolution for detecting these fields. Measuring the vector field at a single point in space using single defects, however, remains an outstanding challenge. We demonstrate that careful optimization of the static bias field can enable simultaneous measurement of multiple magnetic field components with enhanced sensitivity by leveraging the nonlinear Zeeman shift from transverse magnetic fields, realizing an improvement in transverse sensitivity from > 200µT/√Hz (no bias field) to 30µT/√Hz. This work quantifies the trade-off between the increased frequency shift from second-order Zeeman effects with decreasing contrast as off-axis field components increase, demonstrating the measurement of multiple components of the magnetic field from an exemplar antiferromagnet with a complex magnetic texture. © 2024, CC BY.

关键词： Magnetometry

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Real-time in situ study of adsorption kinetics in PMMA thin films using infrared spectroscopy

Real-time in situ study of adsorption kinetics in PMMA thin ...

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Computational Optical Sensing and Imaging, COSI 2022

作者： Lee, Tse-Ang Kowal, Gina Peng, Jessie Hutter, Tanya Department of Mechanical Engineering University of Texas at Austin AustinTX78712 United States Department of Psychology University of Texas at Austin AustinTX78712 United States Department of Biomedical Engineering University of Texas at Austin AustinTX78712 United States Materials Science and Engineering Program Texas Materials Institute University of Texas at Austin AustinTX78712 United States

Studying adsorption in polymers is important for many applications. We present results on real-time in situ adsorption of ethanol and water in thin polymethyl methacrylate (PMMA) layers using attenuated total reflecti... 详细信息

ISBN: (纸本)9781557528209

关键词： Polymethyl methacrylates

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Sensitivity improvement of Au-nanoparticle-based colorimetric probes via surface decoration of carbon quantum dots

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New Journal of Chemistry 2024年第22期48卷 10053-10059页

作者： Li, Yi-Ting Lo, Chien Feng Lin, Kuan-Han Liao, Pin-Chao Juan, Joon Ching Hsiao, Po-Hsuan Chen, Chia-Yun Department of Materials Science and Engineering National Cheng-Kung University Tainan 70101 Taiwan Program on Semiconductor Packaging and Testing Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan 70101 Taiwan Nanotechnology & Catalysis Research Centre Institute for Advanced Studies University of Malaya Kuala Lumpur 50603 Malaysia Hierarchical Green-Energy Materials (Hi-GEM) Research Center National Cheng Kung University No. 1 University Road Tainan 70101 Taiwan

Visually colorimetric sensing of hazardous metallic ions based on gold nanoparticles (AuNPs) has been considered a facile, on-site, and reliable monitoring route, yet the improvement of detection limit, as well as environmental pH tolerance, is still needed. Herein, we present an integrated probe design based on functionalizing AuNP cores with carbon quantum dots (CQD) as colorimetric probes for tracing Cu²⁺ ions with a limit of detection as low as 18.7 nM. Improved detection selectivity was elucidated with the reduction in thiol groups bound between CQD decorations and AuNP probes initiated by oxidation of Cu²⁺ ion analytes, thus separating crossly connected probes, depending on tracing Cu²⁺ concentrations. Moreover, distributed CQDs with negative potentials allowed the stabilization of dispersed AuNPs against re-aggregation, which caused the gradual morphological transition from aggregated features to dispersed states in microscopic view, and eventually, reflected the gradual color change from red to purple-red. The correlated practicality of colorimetric detection of the Cu²⁺ ion was further validated with sound-sensing selectivity, environmental pH resistance and tests on real samples. © 2024 The Royal Society of Chemistry

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Challenges for and Pathways toward Li-MetalBased All-Solid-State Batteries

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ACS ENERGY LETTERS 2021年第4期6卷 1399-1404页

作者： Albertus, Paul Anandan, Venkataramani Ban, Chunmei Balsara, Nitash Belharouak, Ilias Buettner-Garrett, Josh Chen, Zonghai Daniel, Claus Doeff, Marca Dudney, Nancy J. Dunn, Bruce Harris, Stephen J. Herle, Subramanya Herbert, Eric Kalnaus, Sergiy Libera, Joesph A. Lu, Dongping Martin, Steve McCloskey, Bryan D. McDowell, Matthew T. Meng, Y. Shirley Nanda, Jagjit Sakamoto, Jeff Self, Ethan C. Tepavcevic, Sanja Wachsman, Eric Wang, Chunsheng Westover, Andrew S. Xiao, Jie Yersak, Thomas Department of Chemical and Biomolecular Engineering University of Maryland College Park Maryland 20742 United States Ford Motor Company Dearborn Michigan 48121 United States Mechanical Engineering Department University of Colorado Boulder Colorado 80309 United States Department of Chemical and Biomolecular Engineering and Lawrence Berkeley National Laboratory Materials Sciences Division University of California Berkeley California 94720 United States Energy and Transportation Science Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 United States Solid Power Inc. Louisville Colorado 80027 United States Chemical Sciences and Engineering Division Argonne National Laboratory 9700 South Cass Avenue Argonne Illinois 60439 United States Lawrence Berkeley National Laboratory Energy Storage and Distributed Resources Division University of California Berkeley California 94720 United States Department of Materials Science and Engineering University of California Los Angeles California 90095 United States Applied Materials Inc. 3225 Oakmead Village Drive B12_2F6 Santa Clara California 95054 United States Department of Materials Science and Engineering Michigan Technological University Houghton Michigan 49931 United States Energy and Environmental Directorate Pacific Northwest National Laboratory Richland Washington 99352 United States Department of Materials Science & Engineering Iowa State University of Science & Technology Ames Iowa 50011 United States Woodruff School of Mechanical Engineering and School of Materials Science and Engineering Georgia Institute of Technology Atlanta Georgia 30332 United States Department of NanoEngineering and Materials Science and Engineering Program University of California San Diego La Jolla California 92093 United States Department of Materials Science and Engineering and Department of Mechanical Engineering University of Michigan Ann Arbor Michigan 48109 United States Chemical and Materials Systems Laborat

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Opto2P-FCM: A MEMS Based Miniature Two-Photon Microscope with Patterned Optogenetic Stimulation

Opto2P-FCM: A MEMS Based Miniature Two-Photon Microscope wit...

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Microscopy Histopathology and Analytics, Microscopy 2024 - Part of Optica Biophotonics Congress: Biomedical Optics

作者： Futia, Gregory L. Zohrabi, Mo McCullough, Connor Teel, Alec de Souza, Fabio Simoes Oroke, Ryan Bright, Victor M. Restrepo, Diego Gopinath, Juliet T. Gibson, Emily A. Department of Bioengineering University of Colorado Anschutz Medical Campus AuroraCO80045 United States Department of Cell and Developmental Biology University of Colorado Anschutz Medical Campus AuroraCO80045 United States Department of Electrical Computer and Energy Engineering University of Colorado BoulderCO80309 United States Department of Mechanical Engineering University of Colorado BoulderCO80309 United States Department of Physics University of Colorado BoulderCO80309 United States Materials Science and Engineering Program University of Colorado BoulderCO80309 United States

Miniaturized microscopes for monitoring neural activity are an indispensable tool for neuroscience research. We present a novel MEMS based miniature microscope with patterned optogenetic stimulation capabilities enabl... 详细信息

ISBN: (纸本)9781957171340

关键词： Microscopes

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Nonsaturated large magnetoresistance and transport dynamics in a n-doped cryogenic WSe2 field-effect device

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Physical Review B 2025年第12期111卷 125307-125307页

作者： Wei-Chen Lin Ching-Chen Yeh Jia-Zhu Zou Nhat Anh Nguyen Phan Inayat Uddin Hai Yen Le Thi Kenji Watanabe Takashi Taniguchi Gil-Ho Kim Department of Engineering and System Science National Tsing Hua University Hsinchu 300 Taiwan Taiwan International Graduate Program Academia Sinica Taipei 115 Taiwan Department of Physics National Taiwan University Taipei 106 Taiwan Department of Electrical and Computer Engineering Sungkyunkwan University (SKKU) Suwon 164 Republic of Korea Sungkyunkwan Advanced Institute of Nano Technology (SAINT) Sungkyunkwan University (SKKU) Suwon 16419 Republic of Korea Research Center for Electronic and Optical Materials National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan Research Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan

Interest in the two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) continues to intensify, driven by their suitable band gaps to supplant silicon as next-generation semiconductor materials. Among various TMDs, tungsten diselenide (WSe2) is renowned for its superior electrical properties in carrier density and mobility under ambient conditions. Despite its notable attributes, the behavior of monolayer WSe2 in the electron-doped regime under cryogenic conditions remains largely uncharted, particularly concerning its magnetotransport properties. In this study, we reveal the transport mechanisms of monolayer WSe2 from high temperatures down to the cryogenic regime. As evident by Efros–Shklovskii variable-range hopping (E-S VRH) in the cryogenic regime, strong Coulomb interactions arise between electrons. Above 8 K, an uncommon nonsaturated quadratic large magnetoresistance (MR) can be explained by the wave-function shrinkage model, which is consistent with the E-S VRH transport mechanism. Notably, the nonsaturated quadratic large MR shows a magnitude up to 1740% at 13 T. These findings underscore the potential applications for monolayer WSe2 in cryogenic field-effect devices, magnetic sensors, and memory devices and mark a significant advance in magnetotransport research.

关键词： Monolayers

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