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Selective lead ion sensing via cotton pad-based Na2EDTA capped AuNPs: A smartphone-assisted colorimetric method

Chemosphere 2025年 372卷 144095页

作者： Sultana, Evana Rana, Md Zewel Al Mamun, Muhammad Shamim Saad Aly, Mohamed Aly Khedr, Ghada E. Ahmed, Jamil Alahmad, Waleed Chemistry Discipline Khulna University Khulna9208 Bangladesh Chemical & Materials Engineering University of Nevada Reno 1664 North Virginia Street RenoNV89557 United States Guangdong Shenzhen518055 China Department of Analysis and Evaluation Egyptian Petroleum Research Institute Cairo11727 Egypt Department of Chemistry Faculty of Science at Chulalongkorn University Bangkok10330 Thailand School of Electrical and Computer Engineering Georgia Institute of Technology AtlantaGA30332 United States

Herein, Na2EDTA-capped AuNPs specifically designed for selective smartphone-assisted colorimetric detection are synthesized and characterized. Na2EDTA-capped AuNPs was synthesized and characterized by UV–Visible spectroscopy, ATR, Raman, XRD, SEM and EDX. The calculated activation energy of the produced nanoparticles was 0.2 eV. Using XRD and SEM, the average crystallite size was found to be approximately 25 nm. Only Pb2+ and Cd2+, among the following metal ions: Mg2+, K+, Ca2+, Co2+, Ni2+, Ba2+, Hg+, Bi2+, Pb2+, and Cd2+, caused the AuNa2EDTA solution's hue to shift from reddish in color to blue. Pb2+ and Cd2+ were distinguished using a Na2S solution. Cotton pad with AuNa2EDTA integrated served as the substrate for metal ion adsorption. The GIMP software-supported smartphone was used to implement the color contrast (R) method. In the 10–2000 μM range, a straight line represented the relationship between 1/R and Pb2+ ion concentrations, with a limit of detection (LOD) of 0.28 μM was revealed. Real water sample collected from Rupsa River, Khulna, Bangladesh was tested by the developed colorimetric method to be 80 μM of Pb2+ ion. Combining the prevalence of smartphones and the potential of nanotechnology, a cotton-pad based platform functionalized with AuNa2EDTA may be a ground-breaking method for the detection of Pb2+ ions in various media. © 2025 Elsevier Ltd

关键词： Crystallite size

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Quantitative modeling of point defects in β-Ga₂O₃ combining hybrid functional energetics with semiconductor and processes thermodynamics

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Physical Chemistry Chemical Physics 2025年第21期27卷 2025 May 16页

作者： Arnab, K.A. Stephens, M. Maxfield, I. Lee, C. Ertekin, E. Frodason, Y.K. Varley, J.B. Scarpulla, M.A. Department of Materials Science and Engineering University of Utah Salt Lake City 84112 UT United States Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign Urbana 61801 IL United States The Grainger College of Engineering University of Illinois Urbana-Champaign Urbana 61801 IL United States Materials Research Laboratory University of Illinois at Urbana-Champaign Urbana 61801 IL United States Centre for Materials Science and Nanotechnology Physics University of Oslo Oslo Norway Lawrence Livermore National Laboratory Livermore 93106 CA United States Department of Electrical and Computer Engineering University of Utah Salt Lake City 84112 UT United States

β-Gallium oxide (β-Ga2O3) is of high interest for power electronics because of its unique combination of melt growth, epitaxial growth, n-type dopability, ultrawide bandgap, and high critical field. Optimization of ... 详细信息

β-Gallium oxide (β-Ga₂O₃) is of high interest for power electronics because of its unique combination of melt growth, epitaxial growth, n-type dopability, ultrawide bandgap, and high critical field. Optimization of crystal growth processes to promote beneficial defects and suppress harmful ones requires accurate quantitative modelling of both native and impurity defects. Herein we quantitatively model defect concentrations as a function of bulk crystal growth conditions and demonstrate the necessity of including effects such as bandgap temperature dependence, chemical potentials from thermochemistry, and defect vibrational entropy in modelling based on defect formation energies computed by density functional theory (DFT) with hybrid functionals. Without these contributions, grossly-erroneous and misleading predictions arise, e.g. that n-type doping attempts would be fully compensated by Ga vacancies. Including these effects reproduces the experimental facts that melt-grown Sn-doped β-Ga₂O₃ crystals are conductive with small compensation while annealing the same crystals in O₂ at intermediate temperatures renders them insulating. To accomplish this modeling, we developed a comprehensive modelling framework (KROGER) based on calculated defect formation energies and flexible thermodynamic conditions. These capabilities allow KROGER to capture full and partial defect equilibria amongst native defects and impurities occurring during specific semiconductor growth or fabrication processes. We use KROGER to model 873 charge-states of 259 defects involving 19 elements in conditions representing bulk crystal growth by edge-fed growth (EFG) and annealing in oxygen. Our methodology is transferrable to a wide range of materials beyond β-Ga₂O₃. The integration of thermodynamic and first-principles modelling of point defects provides insight into optimization of point defect populations in growth and proc

关键词： Cooling

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Synthesis of churros-like V2Se9 nanostructures for ultrasensitive electrochemical detection of oxalic acid in urine with portable point-of-care diagnostic devices

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Biosensors and Bioelectronics 2025年 285卷 117589页

作者： Shi, Peizheng Ye, Chen Sun, Zhuang Sun, Kaiqiang Zhao, Ningbin Pourfakhr, Mahan Cai, Tao Nishimura, Kazuhito Jiang, Nan Tsai, Hsu-Sheng Wu, Lidong Wu, Wenqi Yu, Jiancheng Fu, Li Xu, Lixin Chen, Jun Lin, Cheng-Te College of Materials Science and Engineering Zhejiang University of Technology Hangzhou310014 China Qianwan Institute of CNITECH Ningbo315336 China State Key Laboratory of Advanced Marine Materials Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo315201 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing100049 China Department of Bioengineering University of California Los AngelesCA90095 United States School of Physics Harbin Institute of Technology Harbin150001 China Key Laboratory of Control of Quality and Safety for Aquatic Products Chinese Academy of Fishery Sciences Beijing100141 China Department of Urology The Second Affiliated Hospital of Guangzhou Medical University Guangdong 510260 China Guangdong Key Laboratory of Urology Guangzhou Medical University Guangdong 511495 China Institute of Mass Spectrometry Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application Ningbo University Ningbo315211 China Zhenhai Institute of Mass Spectrometry Ningbo315211 China Faculty of Electrical Engineering and Computer Science Ningbo University Ningbo315211 China College of Materials and Environmental Engineering Hangzhou Dianzi University Hangzhou310018 China

The binding of oxalic acid (OA) with metal ions, particularly calcium ions, is a key factor in kidney stone formation, as it produces insoluble calcium oxalate, which crystallizes and accumulates in the kidneys. Consequently, OA in urine is commonly considered a significant biomarker for clinical diagnosis and early screening of kidney stones. This study reports churros-like V2Se9 nanostructures synthesized using a solvothermal method (high pressure and temperature) for sensitive and selective electrochemical detection of OA in urine. The electrodes made of churros-like V2Se9 hybridized with reduced graphene oxide (rGO) for OA recognition, demonstrated a linear range from 20 nM to 4 mM, with an extremely low detection limit of 9.7 nM. To enable fast, user friendly, and accurate point-of-care testing (POCT) for OA in urine samples, we designed and developed a portable workstation integrated with smartphone for data visualization. This is the first study to utilize the V2Se9 system for highly sensitive biosensor applications, highlighting its potential to advance screening techniques for key indicators of kidney stones by incorporating novel transition metal chalcogenide nanomaterials in POCT devices. © 2025 Elsevier B.V.

关键词： Electrochemical biosensors

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Investigation of Noise at a Microelectrode during a Faradaic Reaction

ACS Electrochemistry

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ACS Electrochemistry 2025年第4期1卷 552-559页

作者： Kaden Wheeler Joseph Gott Brian Roehrich Julia Chung Kajal Kajal Jaroslaw Syzdek Joao Hespanha Lior Sepunaru Department of Chemistry and Biochemistry University of California at Santa Barbara Santa Barbara California 93106 United States Interdepartmental Program in Biomolecular Science and Engineering University of California at Santa Barbara Santa Barbara California 93106 United States Bio-Logic USA LLC 9050 Executive Park Dr. Ste. 110C Knoxville Tennessee 37923 United States Electrical and Computer Engineering Department University of California at Santa Barbara Santa Barbara California 93106 United States

Measurement of small currents is often impeded by a suboptimal signal-to-noise ratio, largely due to background noise. This background noise significantly constrains the range of catalysts accessible for interrogation via micro- and nanoscale electrochemistry. In response, this work reveals how background noise scales in the presence of induced Faradaic reactions. We measured noise under a series of electrochemical conditions and discovered that the induced noise from a Faradaic reaction scales directly with current. Complementary electrochemical impedance spectroscopy measurements demonstrated that diffusional resistance dictates the noise of Faradaic reactions, independent of the electrochemical mechanism. The noise source is thermal in origin and propagates in a predictable trend, which is inversely proportional to the equivalent diffusional resistance of the analyte. The universality of the observed phenomenon allows for better deconvolution of measured charge from background noise, thus assisting in achieving higher resolution and measurement precision, which is a key in micro- and nanoscale electrochemical measurements.

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Role of high energy photons in dual spectral source rapid isothermal CVD

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JOURNAL OF ELECTRONIC materials 1997年第10期26卷 1184-1188页

作者： Singh, R Chen, Y Department of Electrical and Computer Engineering Material Science and Engineering Program Clemson University Clemson Department of Electrical and Computer Engineering Clemson University Clemson

The use of tungsten halogen lamps and the deuterium lamp as the source of thermal and optical energies has been exploited to deposit thin films of Ta2O5 on Si and conducting substrates, The leakage current densities are as low as 10(-10) A/cm(2) for gate voltage under 5V. Photons in visible, ultraviolet, and vacuum ultraviolet (lambda < 800 nm) regions provide higher bulk and surface diffusion coefficients as well as reduced activation energy for the chemical process involved in the chemical vapor deposition process. The low thermal mass of the substrate provides limited reaction processing capability. The photochemical and photophysical processes allow the participating atoms and molecules to adjust their bond geometries and occupy sites which result in overall reduction of stress and strain energy and provide materials with overall low microscopic defects at low processing temperature and with high throughput. New experimental results of Al-Ta2O5-Si3N4-poly Si-Al structure are presented. The leakage current-voltage characteristics are better than those reported by other researchers.

关键词： dielectrics metalorganic chemical vapor deposition (MOCVD) rapid isothermal processing (RIP) Ta2O5

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A materials Foundation Model via Hybrid Invariant-Equivariant Architectures

arXiv

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arXiv 2025年

作者： Yan, Keqiang Bohde, Montgomery Kryvenko, Andrii Xiang, Ziyu Zhao, Kaiji Zhu, Siya Kolachina, Saagar Sarıtürk, Doğuhan Xie, Jianwen Arróyave, Raymundo Qian, Xiaoning Qian, Xiaofeng Ji, Shuiwang Department of Computer Science & Engineering Texas A&M University College StationTX United States Department of Electrical & Computer Engineering Texas A&M University College StationTX United States Department of Materials Science & Engineering Texas A&M University College StationTX United States Lambda Inc. United States J. Mike Walker’66 Department of Mechanical Engineering Texas A&M University College StationTX United States Wm Michael Barnes’64 Department of Industrial and Systems Engineering Texas A&M University College StationTX United States Brookhaven National Laboratory UptonNY United States Department of Physics & Astronomy Texas A&M University College StationTX United States

materials foundation models can predict energy, force, and stress of materials and enable a wide range of downstream discovery tasks. A key design choice involves the trade-off between invariant and equivariant architectures. Invariant models offer computational efficiency but may not perform well when predicting high-order outputs. In contrast, equivariant models can capture high-order symmetries, but are computationally expensive. In this work, we propose HIENet, a hybrid invariant-equivariant foundation model that integrates both invariant and equivariant message passing layers. HIENet is designed to achieve superior performance with considerable computational speedups over prior models. Experimental results on both common benchmarks and downstream materials discovery tasks demonstrate the efficiency and effectiveness of HIENet. © 2025, CC BY-NC-SA.

关键词： Prediction models

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Space-Charge Limited Schottky Diodes with Wide-Bandgap Thin-Film Oxide Heterojunctions

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ACS Applied Electronic materials 2025年

作者： Lim, Jihun Department of Department of Semiconductor Science and Technology Jeonbuk National University Jeonju 54896 South Korea Research Institute for Materials and Energy Sciences Jeonbuk National University Jeonju 54896 South Korea Department of Electrical and Computer Engineering University of Michigan Ann Arbor 48109 MI United States

Noncrystalline thin-film Schottky diodes are cost-effective but often exhibit unreliable electrical characteristics due to material imperfections. In this work, a Schottky diode structure is presented utilizing in situ grown Ta₂O₅ and ZnO thin films deposited at room temperature. The low conduction band offset across the interface of the heterogeneous oxides facilitates efficient electron injection under forward bias. Capacitance-voltage characterization reveals a robust Schottky barrier at the Au/Ta₂O₅ interface without a significant barrier thinning effect, enabling high-voltage breakdown up to 65 V and a high on/off ratio of 1 × 10⁸. In demonstrations, the thin-film structure shows Schottky contact characteristics using even a relatively low work function metal of ITO, allowing the operation of transparent Schottky diodes. The diodes show additional potential for applications, including RF-to-DC conversion leveraging space charge capacitance at the Ta₂O₅/ZnO junction and rectifying resistive random access memory devices. This work highlights a promising approach for integrating low-cost, high-reliability Schottky diodes into back-end-of-line processes for wireless electronics and power devices. © 2025 American Chemical Society.

关键词： breakdown voltage crossbar memory space charge capacitance thin-film Schottky diode wide bandgap oxide semiconductor

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Emergent Hidden Multipolar State in the Triangular Lattice Magnet TmZn2GaO5

arXiv

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arXiv 2025年

作者： Ennis, Matthew Bag, Rabindranath Cookmeyer, Tessa Stone, Matthew B. Kolesnikov, Alexander I. Hong, Tao Balents, Leon Haravifard, Sara Department of Physics Duke University DurhamNC United States Kavli Institute for Theoretical Physics University of California Santa BarbaraCA United States Neutron Scattering Division Oak Ridge National Laboratory Oak RidgeTN United States Department of Mechanical Engineering and Materials Science Duke University DurhamNC United States Department of Electrical and Computer Engineering Duke University DurhamNC United States

TmZn2GaO5 is a newly synthesized triangular lattice magnet that exhibits a unique quantum phase characterized by strong Ising anisotropy, a pseudo-doublet crystal electric field ground state, and a low-energy gapped excitation at the K point. Unlike its well-known counterparts, TmMgGaO4 and YbMgGaO4, this material crystallizes in a distinct hexagonal structure, leading to a cleaner platform for investigating frustrated magnetism. Magnetic susceptibility, heat capacity, and inelastic neutron scattering measurements confirm the absence of long-range magnetic order down to 50 mK, placing TmZn2GaO5 in a distinct region of the transverse-field Ising model phase diagram. Theoretical calculations based on spin-wave theory and mean-field modeling reproduce key experimental observations, reinforcing the material’s placement in a quantum disordered/multipolar state. These results highlight its potential for exploring quantum disordered states, anisotropic excitations, and exotic quantum phases in frustrated spin systems. Copyright © 2025, The Authors. All rights reserved.

关键词： Magnetic susceptibility

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Anisotropic Strain Relaxation-Induced Directional Ultrafast Carrier Dynamics in RuO2 Films

arXiv

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arXiv 2025年

作者： Jeong, Seung Gyo Choi, In Hyeok Lee, Seungjun Oh, Jin Young Nair, Sreejith Lee, Jae Hyuck Kim, Changyoung Seo, Ambrose Choi, Woo Seok Low, Tony Seok, Jong Jalan, Bharat Department of Chemical Engineering and Materials Science University of Minnesota−Twin Cities MinneapolisMN55455 United States Gwangju61005 Korea Republic of Department of Electrical and Computer Engineering University of Minnesota MinneapolisMN55455 United States Department of Physics Sungkyunkwan University Suwon16419 Korea Republic of Department of Physics and Astronomy Seoul National University Seoul08826 Korea Republic of Department of Physics and Astronomy University of Kentucky LexingtonKY40506 United States

Ultrafast light-matter interactions inspire potential functionalities in picosecond optoelectronic applications. However, achieving directional carrier dynamics in metals remains challenging due to strong carrier scattering within a multiband environment, typically expected to isotropic carrier relaxation. In this study, we demonstrate epitaxial RuO2/TiO2 (110) heterostructures grown by hybrid molecular beam epitaxy to engineer polarization-selectivity of ultrafast light-matter interactions via anisotropic strain engineering. Combining spectroscopic ellipsometry, X-ray absorption spectroscopy, and optical pump-probe spectroscopy, we revealed the strong anisotropic transient optoelectronic response of strain-engineered RuO2/TiO2 (110) heterostructures along both in-plane [001] and [1 1 0] crystallographic directions. Theoretical analysis identifies strain-induced modifications in band nesting as the underlying mechanism for enhanced anisotropic carrier relaxation. These findings establish epitaxial strain engineering as a powerful tool for tuning anisotropic optoelectronic responses in metallic systems, paving the way for next-generation polarization-sensitive ultrafast optoelectronic devices. © 2025, CC BY.

关键词： Spectroscopic ellipsometry

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Noise-immune quantum correlations of intense light

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Nature Photonics 2025年 1-7页

作者： Zia Uddin, Shiekh Rivera, Nicholas Seyler, Devin Sloan, Jamison Salamin, Yannick Roques-Carmes, Charles Xu, Shutao Sander, Michelle Y. Kaminer, Ido Soljačić, Marin Department of Physics Massachusetts Institute of Technology CambridgeMA United States Research Laboratory of Electronics Massachusetts Institute of Technology CambridgeMA United States Department of Physics Harvard University CambridgeMA United States School of Applied and Engineering Physics Cornell University IthacaNY United States CREOL The College of Optics and Photonics University of Central Florida OrlandoFL United States E. L. Ginzton Laboratory Stanford University StanfordCA United States Department of Electrical and Computer Engineering and BU Photonics Center Boston University BostonMA United States Division of Materials Science and Engineering Boston University BrooklineMA United States Department of Biomedical Engineering Boston University BostonMA United States Department of Electrical and Computer Engineering Technion-Israel Institute of Technology Haifa Israel

Lasers with high intensity generally exhibit strong intensity fluctuations far above the shot-noise level. Taming this noise is pivotal to a wide range of applications, both classical and quantum. Here we demonstrate the creation of intense light with quantum levels of noise even when starting from inputs with large amounts of excess noise. In particular, we demonstrate how intense squeezed light with intensities approaching 0.1 TW cm−2, but noise at or below the shot-noise level, can be produced from noisy inputs associated with high-power amplified laser sources (an overall noise reduction of 30-fold). On the basis of a new theory of quantum noise in multimode systems, we show that the ability to generate quantum light from noisy inputs results from multimode quantum correlations, which maximally decouple the output light from the dominant noise channels in the input light. As an example, we demonstrate this effect for femtosecond pulses in nonlinear fibres, but the noise-immune correlations that enable our results are generic to many other nonlinear systems in optics and beyond. © The Author(s), under exclusive licence to Springer Nature Limited 2025.

关键词： Nonlinear optics

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