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Evolution of 14-connected Zr₆ Secondary Building Units through Postsynthetic Linker Incorporation (Jun, 10.1021/acsami.1c07701, 2021)

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ACS APPLIED materials & INTERFACES 2021年第33期13卷 40155-40155页

作者： Hurlock, Matthew J. Hao, Leiduan Kriegsman, Kyle W. Guo, Xiaofeng O'Keeffe, Michael Zhang, Qiang Department of Chemistry Washington State University Pullman Washington 99164 United States Department of Chemistry Materials Science and Engineering Program Washington State University Pullman Washington 99164 United States School of Molecular Sciences Arizona State University Tempe Arizona 85287 United States

Two new zirconium MOFs, WSU-6 and WSU-7, were synthesized through postsynthetic modifications. In both cases, linker insertion was conducted on a MOF consisting of eight-connected (8-c) Zr6 cluster and four-connected (4-c) ETTC linker, WSU-5, which possesses the uncommon 4, 8-c scu-c topology. The insertion of 1, 4-benzenedicarboxylate into the MOF formed the new 4, 12-c mjh topology, WSU-6. Interestingly, when 2, 6-naphthalenedicarboxylate was inserted, WSU-7 can be formed, which possesses a new 4, 14-c jkz topology. WSU-7 contains very rare 14-c Zr6 secondary building units (SBUs) and is the first MOF to have a Zr6 SBUs with connectivity greater than 12. The three Zr-MOFs were structurally characterized, and the photoluminescence properties of the materials were also studied.

关键词： metal−organic frameworks postsynthetic ligand insertion new topology 14-connected Zr6 SBU luminescence

Microarchitectural Design Variation of the Echinoid Skeleton: A 3D Structural and Mechanical Study of Paracentrotud lividusi

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SSRN

SSRN 2024年

作者： Perricone, Valentina Cesarano, Pasquale Deb, Mainak Lublin, Derek Mutalipassi, Mirko Pappalardo, Lucia Kisailus, David Marmo, Francesco Department of Materials Science and Engineering University of California Irvine United States Department of Structures for Engineering and Architecture University of Naples Federico II Italy Materials and Manufacturing Technology Program University of California Irvine United States Department of Integrative Marine Ecology Stazione Zoologica Anton Dohrn Villa Comunale Napoli Italy Palermo Italy Italy Wipro Technologies

Biological materials usually show remarkable mechanical properties, despite being composed of fragile and simple components (i.e., strong but brittle minerals and tough but weak proteins). These properties are conferred through a multiscale design, in which shapes, structures and composition are coherently organized leading to unique emerging strategies. Noteworthy is the case of the sea urchin skeleton, a hierarchical tasseled structure composed of multiple calcitic plates that are both lightweight and load-bearing. At the microscale, each plate shows a unique species-specific pattern consisting of a porous 3D lattice-like meshwork of trabeculae, called stereom. Interestingly, the stereom architecture is extremely complex and variable in different basic types, each one characterized by a unique topology and structural behaviors. In this context, the present study provides an in-depth analysis of the microarchitectural variability in the sea urchin Paracentrotus lividus. Accordingly, micro-CT scans, image analysis, 3D modeling, and linear elastic FE-Analysis were conducted to provide new insights about the topological and geometrical variability of the different stereom types, and their region-specific mechanical behavior calculated for tensile and shear loading. These results are of value to ameliorate the understanding of the mechanical function of the stereom variability, as well as to identify adaptive solutions useful for future biomimetic transfer applications. © 2024, The Authors. All rights reserved.

关键词： Finite element method

Impact of Quantum Well Thickness on Efficiency Loss in InGaN/GaN LEDs: Challenges for Thin-Well Designs

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arXiv 2025年

作者： Li, Xuefeng Pant, Nick Rahman, Sheikh Ifatur Armitage, Rob Rajan, Siddharth Kioupakis, Emmanouil Feezell, Daniel University of New Mexico AlbuquerqueNM87106 United States Department of Materials Science & Engineering University of Michigan Ann ArborMI48109 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43210 United States Lumileds LLC San JoseCA95131 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States

We investigate the impact of quantum well (QW) thickness on efficiency loss in c-plane InGaN/GaN LEDs using a small-signal electroluminescence (SSEL) technique. Multiple mechanisms related to efficiency loss are independently examined, including injection efficiency, carrier density vs. current density relationship, phase space filling (PSF), quantum confined stark effect (QCSE), and Coulomb enhancement. An optimal QW thickness of around 2.7 nm in these InGaN/GaN LEDs was determined for quantum wells having constant In composition. Despite better control of deep-level defects and lower carrier density at a given current density, LEDs with thin QWs still suffer from an imbalance of enhancement effects on the radiative and intrinsic Auger-Meitner recombination coefficients. The imbalance of enhancement effects results in a decline in internal quantum efficiency (IQE) and radiative efficiency with decreasing QW thickness at low current density in LEDs with QW thicknesses below 2.7 nm. We also investigate how LED modulation bandwidth varies with quantum well thickness, identifying the key trends and their implications for device performance. Copyright © 2025, The Authors. All rights reserved.

关键词： Semiconductor quantum wells

Machine Learning-Enhanced Design of Lead-Free Halide Perovskite materials Using Density Functional Theory

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arXiv 2024年

作者： Kumar, Upendra Kim, Hyeon Woo Maurya, Gyanendra Kumar Raj, Bincy Babu Singh, Sobhit Kushwaha, Ajay Kumar Cho, Sung Beom Ko, Hyunseok Jinju52851 Korea Republic of Department of Materials Science and Engineering Hanyang University Seoul04763 Korea Republic of Department of Physics GLA University Mathura281406 India School of Material Science and Engineering Pusan National University 2 Busandaehak-ro 63beon-gil Geumjeong-gu Busan46241 Korea Republic of Department of Mechanical Engineering The University of Rochester New York14611 United States Materials Science Program University of Rochester RochesterNY14627 United States Department of Metallurgy Engineering and Materials Science Indian Institute of Technology Indore Khandwa Road Simrol Indore453552 India Department of Energy Systems Research Ajou University Suwon16499 Korea Republic of

The investigation of emerging non-toxic perovskite materials has been undertaken to advance the fabrication of environmentally sustainable lead-free perovskite solar cells. This study introduces a machine learning methodology aimed at predicting innovative halide perovskite materials that hold promise for use in photovoltaic applications. The seven newly predicted materials are as follows: CsMnCl4, Rb3Mn2Cl9, Rb4MnCl6, Rb3MnCl5, RbMn2Cl7, RbMn4Cl9, and CsIn2Cl7. The predicted compounds are first screened using a machine learning approach, and their validity is subsequently verified through density functional theory calculations. CsMnCl4 is notable among them, displaying a bandgap of 1.37 eV, falling within the Shockley-Queisser limit, making it suitable for photovoltaic applications. Through the integration of machine learning and density functional theory, this study presents a methodology that is more effective and thorough for the discovery and design of materials. © 2024, CC BY.

关键词： Density functional theory

Synthesis of spray deposited transition metals doped (Cr, Mn, Fe, Ni, and Cu) compositionally complex ZnO thin films with enhanced band gap and magnetism

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Results in Materials

Results in materials 2022年 13卷

作者： Al Hassan, Md Rahat Asrafuzzaman Islam, Md Aminul Salam, Kamruzzaman Amin, Kazi Faiza Hasan, Md Khalid Department of Glass & Ceramic Engineering Rajshahi University of Engineering & Technology (RUET) Rajshahi 6204 Bangladesh Department of Materials Science and Engineering Rajshahi University of Engineering & Technology (RUET) Rajshahi 6204 Bangladesh Department of Materials and Metallurgical Engineering Bangladesh University of Engineering & Technology (BUET) Dhaka 1000 Bangladesh

Compositionally complex ceramics (CCCs) is now considered as a subgroup of high entropy ceramics (HECs);which focuses on the further opportunities of exploring wide compositional spaces and low entropy options of HECs. This study for the first time attempts to render high configurational disorder in the cationic site of ZnO lattice through the incorporation of higher concentration quinary 3d transition metals dopants i.e. Cr, Mn, Fe, Ni, and Cu. The authors here demonstrate the synthesis of pure ZnO and compositionally complex (Ba_xSr_xMn_xFe_xNi_x) Zn_1-5xO (where x = 0.02, 0.04, and 0.06;the samples denoted as 10CCZO, 20CCZO, and 30CCZO respectively) thin films by low-cost spray pyrolysis technique at 250 °C. In order to investigate the unique wurtzite phase stability of all CCZO crystal structures, XRD analyses were carried out with Rietveld refinement. XRD study showed the single hexagonal wurtzite phase presence of P63mc space group in all CCZO samples and notable change in lattice parameters with doping increment. SEM results revealed a significant change in surface morphology as it transformed flake-shaped grains for pure ZnO to flower and interconnected flake patterns. UV–visible spectroscopy disclosed enhanced transmittance and optical band gap of 3.94, 3.97 eV in 10CCZO and 20CCZO, respectively. VSM test showed that the magnetization values increased substantially in CCZO thin films indicating the potential prospect of these CCZO in magneto-optical applications. In addition, tuned functional properties were correlated with microstructural features. © 2022 The Authors

关键词： Band gap Compositionally complex ceramics Magnetization Microstructure Mixing entropy

Thermoelectrically Elevated Hydrogel Evaporation for Personal Cooling under Extreme Heat

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arXiv 2025年

作者： Pei, Yu Feng, Tianshi Chambers, Robert Cai, Shengqiang Chen, Renkun Department of Mechanical and Aerospace Engineering University of California San Diego 9500 Gilman Drive La Jolla CA92093 United States Materials Science and Engineering Program University of California San Diego 9500 Gilman Drive La Jolla CA92093 United States

Extreme heat events with wet-bulb temperatures (WBT) above 35°C pose serious risks to human survival, and conventional hydrogel evaporative cooling alone may not provide sufficient relief as it must be maintained at a sufficiently high temperature to achieve effective evaporation in hot, humid conditions. This study integrates thermoelectric devices (TEDs) with hydrogels to create an effective personal cooling solution. TEDs pump heat away from the skin to maintain comfort while simultaneously increasing the hydrogel’s temperature to enhance evaporation. This hybrid system outperforms TEDs or hydrogel alone in extreme conditions (temperature up to 55°C and relative humidity up to 88%, with WBT > 35°C) and can operate for over six hours with a manageable hydrogel and battery weight. The active temperature control of TEDs allows adaptation to changing thermal loads and environments. These results demonstrate the potential of hybrid evaporative and thermoelectric cooling as an efficient, adaptable, and sustainable personal cooling solution to combat extreme heat. Copyright © 2025, The Authors. All rights reserved.

关键词： Evaporative cooling systems

Evolution of electromechanical properties in Fe-doped(Pb,Sr)(Zr,Ti)O_(3) piezoceramics

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Journal of Advanced ceramics 2021年第3期10卷 587-595页

作者： Chuan CHEN Yan WANG Zong-Yue LI Chun LIU Wen GONG Qing TAN Bing HAN Fang-Zhou YAO Ke WANG Joint Laboratory of Electric Power Intelligent Sensing Technology and Application Department of Sensing Technology for Electric PowerGlobal Energy Interconnection Research Institute Co.Ltd.Future Science ParkBeijing 102209China China Aerospace Science and Industry Corporation Beijing 100048China Naqu Branch of Tibet Electric Limited Company Naqu 852000China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Center of Advanced Ceramic Materials and Devices Yangtze Delta Region Institute of Tsinghua UniversityZhejiang 314006China Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China Department of Orthodontics&National Engineering Laboratory for Digital and Material Technology Peking University School and Hospital of StomatologyBeijing 100081China State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong UniversityXi'an 710049China Foshan(Southern China)Institute for New Materials Foshan 528200China

Defects in acceptor-doped perovskite piezoelectric materials have a significant impact on their electrical ***,the defect mediated evolution of piezoelectric and ferroelectric properties of Fe-doped(Pb,Sr)(Zr,Ti)O_(3)(PSZT-Fe)piezoceramics with different treatments,including quenching,aging,de-aging,and poling,was investigated *** vacancies with a cubic symmetry are preserved in the quenched PSZT-Fe ceramics,rendering them robust ferroelectric *** the aged PSZT-Fe polycrystals,defect dipole between Fe dopant and oxygen vacancy has the same orientation with spontaneous polarization Ps,which enables the reversible domain switching and hence leads to the emergence of pinched polarization hysteresis and recoverable strain *** the defect dipoles can be gradually disrupted by bipolar electric field cycling,once again endowing the aged materials with representative ferroelectric *** the poled PSZT-Fe polycrystals,the defect dipoles are reoriented to be parallel to the applied poling field,and an internal bias field aligning along the same direction emerges simultaneously,being responsible for asymmetric hysteresis loops.

关键词： lead-zirconate-titanate(PZT) piezoelectric acceptor defect engineering electromechanical properties

Direct observation of structural phase transformations during continuous phosphorus deposition on Cu(111)

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arXiv 2024年

作者： David, Jiří Jeřábek, František Procházka, Pavel Černý, Miroslav Ciobanu, Cristian V. Průša, Stanislav Šikola, Tomáš Kodambaka, Suneel Kolíbal, Miroslav Institute of Physical Engineering Brno University of Technology Technická 2 Brno616 69 Czech Republic CEITEC BUT. Brno University of Technology Purkyňova 123 Brno612 00 Czech Republic Department of Mechanical Engineering Materials Science Program Colorado School of Mines GoldenCO80401 United States Department of Materials Science and Engineering Virginia Polytechnic Institute State University BlacksburgVA24061 United States

Blue phosphorene - two-dimensional, hexagonal-structured, semiconducting phosphorus - has gained attention as it is considered easier to synthesize on metal surfaces than its allotrope, black phosphorene. Recent studies report different structures of phosphorene, for example, on Cu(111), but the underlying mechanisms of their formation are not known. Here, using a combination of in situ ultrahigh vacuum low-energy electron microscopy and in vacuo scanning tunneling microscopy, we determine the time-evolution of the surface structure and morphology during the deposition of phosphorus on single-crystalline Cu(111). We find that during early stages of deposition, phosphorus intermixes with Cu, resulting in copper phosphide structures. With increasing surface concentration of phosphorus, the phosphide phase disappears and a blue phosphorene layer forms, followed by self-assembly of highly ordered phosphorus clusters that eventually grow into multilayer islands. We attribute the unexpected transformation of stable phosphide to a phosphorene layer, and the previously unreported multilayer growth, to the presence of a large concentration of P2 dimers on the surface. Our results constitute direct evidence for a new growth mode leading to a phosphorene layer via an intermediary phase, which could underpin the growth of other 2D materials on strongly interacting substrates. © 2024, CC BY-SA.

关键词： Self assembly

New Insights into the Effects of Solidification Process on The Thermodynamic Parameters and Mechanical Properties of Cualbenbni Shape Memory Alloy

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SSRN

SSRN 2023年

作者： Silva, David D.S. Vieira, Rafael T. Falcão, Gabriely M.S. Brito, Ieverton C.A. Caluête, Rafael E. Gomes, Rodinei M. Oliveira, Danniel F. Federal University of São Carlos Graduate Program in Materials Science and Engineering SP São Carlos13565-905 Brazil Colorado School of Mines George S. Ansell Department of Metallurgical and Materials Engineering GoldenCO80401 United States Federal University of Paraíba Graduate Program in Materials Science and Engineering PB João Pessoa58051-900 Brazil Federal University of Paraíba Department of Materials Engineering PB João Pessoa58051-900 Brazil Federal University of Paraíba Department of Mechanical Engineering PB João Pessoa58051-900 Brazil

In this work, the influence of the solidification process on the microstructure, thermodynamic parameters and mechanical properties of CuAlBeNbNi shape memory alloy (SMA) was investigated. While directional solidification has been used to improve functional properties in Cu-based SMAs, the squeeze casting process has not yet been explored. The results indicate that the processes of unidirectional solidification and squeeze casting offer an alternative method to modify the thermodynamic parameters, mechanical properties, and microstructural properties of the CuAlBeNbNi SMA while keeping the composition constant. This study aims to fill the knowledge gap regarding the impact of solidification processes on the properties of Cu-based SMAs, specifically investigating CuAlBeNbNi SMAs. © 2023, The Authors. All rights reserved.

关键词： Microstructural evolution