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arXiv 2019年

作者： De Lile, Jeffrey Roshan Lee, So Young Kim, Hyoung-Juhn Pak, Chanho Lee, Seung Geol Department of Organic Material Science and Engineering Pusan National University 2 Busandaehak-ro 63beon-gil Geumjeong-gu Busan46241 Korea Republic of Fuel Cell Research Center Korea Institute of Science and Technology Hwarang-ro 14-gil 5 Seongbuk-gu Seoul02792 Korea Republic of Graduate Program of Energy Technology School of Integrated Technology Institute of Integrated Technology Gwangju Institute of Science and technology 123 Cheomdangwagi-ro Buk-gu Gwangju61005 Korea Republic of

A palladium-based (Pd-based) core@shell catalyst can be modified to achieve the desired oxygen adsorption properties by selecting an appropriate core composition, surface alloying, and compressive strain. Herein, we present the effects of compressive strain, core composition, and surface alloying in Pd3Ni@PdIr(111), Pd3CuNi@PdIr(111), and Pd3Cu@PdIr(111) alloy-core@alloy-shell catalysts on dioxygen adsorption. Using experimental lattice parameters for the unstrained catalysts,-1% to-5%, strain was systematically introduced. The calculated dioxygen-adsorption energies for the surface Pd and surface Ir atoms reveal that the Pd3CuNi@PdIr catalyst has the lowest dioxygen-adsorption energy at a given compressive strain. Bader charge calculations show that the Pd3CuNi@PdIr catalyst surface is the most charge depleted. The d-band model displays an intermediate d-band center downshift for the surface Pd atoms, and the highest downshift for the surface Ir atoms. Due to synergism between charge depletion, the d-band center shift, and the surface alloy effect, the Pd3CuNi@PdIr catalyst has the lowest dioxygen-adsorption energy. The relationship between the experimentally obtained catalyst-surface mass activity and the theoretically calculated d-band center of the surface Pd and the surface Ir is volcano shaped, with the Pd3CuNi@PdIr catalyst at the apex of the volcano. The catalytic activities of these catalysts were observed to follow the order: Pd3CuNi@PdIr >Pd3Cu@PdIr >Pd3Ni@PdIr. This work sheds light on the importance of ligand and strain effects, as well as surface alloying for the fine-tuning of alloy-core@alloy-shell-catalysts during the rational design of catalysts from first principles. Copyright © 2019, The Authors. All rights reserved.

关键词： Electronic structure

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A LRET Nanoplatform Consisting of Lanthanide and Amorphous Manganese Oxide for NIR-II Luminescence Lifetime Imaging of Tumor Redox Status

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Angewandte Chemie 2022年第47期134卷

作者： Dr. Mengyao Zhao Dr. Hongjun Zhuang Dr. Hongxin Zhang Dr. Benhao Li Jiang Ming Prof. Xiaoyuan Chen Prof. Meiwan Chen State Key Laboratory of Quality Research in Chinese Medicine Institute of Chinese Medical Sciences University of Macau Macau 999078 China Departments of Diagnostic Radiology Surgery Chemical and Biomolecular Engineering and Biomedical Engineering Yong Loo Lin School of Medicine and Faculty of Engineering National University of Singapore Singapore 119074 Singapore Contribution: Conceptualization (lead) Investigation (lead) Writing - original draft (lead) Department of Chemistry State Key Laboratory of Molecular Engineering of Polymers and iChem Shanghai Key Laboratory of Molecular Catalysis and Innovative Material Fudan University Shanghai 200433 China Contribution: Investigation (supporting) Nanomedicine Translational Research Program NUS Center for Nanomedicine Yong Loo Lin School of Medicine National University of Singapore Singapore 117597 Singapore Clinical Imaging Research Centre Centre for Translational Medicine Yong Loo Lin School of Medicine National University of Singapore Singapore 117599 Singapore Institute of Molecular and Cell Biology Agency for Science Technology and Research (A*STAR) Singapore 138673 Singapore Contribution: Funding acquisition (lead) Supervision (lead)

Designing luminescence lifetime sensors in the second near-infrared (NIR-II) window is a great challenge due to the difficult structural construction. Here, we report a tumor redox responsive and easily synthesized material, amorphous manganese oxide (MnO x ) with indirect band gap of 1.02 eV, as an energy acceptor to build a luminescence resonance energy transfer (LRET) toolbox for universally regulating NIR-I to NIR-II luminescence lifetimes of lanthanide nanoparticles, in which energy transfer is based on matched energy gap instead of conventional overlapped spectra. We further utilize ytterbium (Yb 3+ )-doped YbNP@MnO x as an NIR-II luminescence lifetime sensor to realize in vitro quantitative redox visualization with relative errors under 5 % in samples covered with mouse skin. Furthermore, HepG2 cells and tumors with high redox state have been accurately distinguished by NIR-II luminescence lifetime imaging. The quantified intracellular and intratumor glutathione (GSH) levels are highly consistent with the commercial kit results, illustrating the reliable redox visualization ability in biological tissue.

关键词： Amorphous Manganese Oxide Lanthanide Luminescence Lifetime Imaging NIR-II LRET Quantitative Redox Visualization

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Resolving spin, valley, and moiré quasi-angular momentum of interlayer excitons in WSe2/WS2 heterostructures

arXiv

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arXiv 2019年

作者： Jin, Chenhao Regan, Emma C. Wang, Danqing Iqbal Bakti Utama, M. Yang, Chan-Shan Cain, Jeffrey Qin, Ying Shen, Yuxia Zheng, Zhiren Watanabe, Kenji Taniguchi, Takashi Tongay, Sefaattin Zettl, Alex Wang, Feng Department of Physics University of California at Berkeley BerkeleyCA94720 United States Graduate Group in Applied Science and Technology University of California at Berkeley BerkeleyCA94720 United States Department of Materials Science and Engineering University of California at Berkeley BerkeleyCA94720 United States Institute of Electro-Optical Science and Technology Undergraduate Program of Electro-Optical Engineering National Taiwan Normal University Taipei11677 Taiwan Material Science Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Kavli Energy NanoSciences Institute University of California Berkeley Lawrence Berkeley National Laboratory BerkeleyCA94720 United States School for Engineering of Matter Transport and Energy Arizona State University TempeAZ85287 United States National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan

Moiré superlattices provide a powerful way to engineer properties of electrons and excitons in two-dimensional van der Waals heterostructures1-11. The moiré effect can be especially strong for interlayer excitons, where electrons and holes reside in different layers and can be addressed separately. In particular, it was recently proposed that the moiré superlattice potential not only localizes interlayer exciton states at different superlattice positions, but also hosts an emerging moiré quasi-angular momentum (QAM) that periodically switches the optical selection rules for interlayer excitons at different moiré sites12,13. Here we report the observation of multiple interlayer exciton states coexisting in a WSe2/WS2 moiré superlattice and unambiguously determine their spin, valley, and moiré QAM through novel resonant optical pump-probe spectroscopy and photoluminescence excitation spectroscopy. We demonstrate that interlayer excitons localized at different moiré sites can exhibit opposite optical selection rules due to the spatially-varying moiré QAM. Our observation reveals new opportunities to engineer interlayer exciton states and valley physics with moiré superlattices for optoelectronic and valleytronic applications. Copyright © 2019, The Authors. All rights reserved.

关键词： Angular momentum

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Enhanced Drug Delivery by Dissolution of Amorphous Drug Encapsulated in a Water Unstable Metal–Organic Framework (MOF)

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Angewandte Chemie 2019年第47期131卷

作者： Kuthuru Suresh Adam J. Matzger Department of Chemistry and the Macromolecular Science and Engineering Program University of Michigan 930 North University Avenue Ann Arbor MI 48109-1055 USA

Encapsulating a drug molecule into a water‐reactive metal–organic framework (MOF) leads to amorphous drug confined within the nanoscale pores. Rapid release of drug occurs upon hydrolytic decomposition of MOF in dissolution media. Application to improve dissolution and solubility for the hydrophobic small drug molecules curcumin, sulindac, and triamterene is demonstrated. The drug@MOF composites exhibit significantly enhanced dissolution and achieves high supersaturation in simulated gastric and/or phosphate buffer saline media. This combination strategy where MOF inhibits crystallization of the amorphous phase and then releases drug upon MOF irreversible structural collapse represents a novel and generalizable approach for drug delivery of poorly soluble compounds while overcoming the traditional weakness of amorphous drug delivery: physical instability of the amorphous form.

关键词： Amorphe Wirkstoffe Metall-organische Gerüste Sofortige Wirkstofffreisetzung Stabilität Wirkstofftransport

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Computed stabilization for a giant fullerene endohedral: Y 2 C 2 @C 1 (1660)-C 108

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Chemical Physics Letters 2018年 710卷 147-149页

作者： Zdeněk Slanina Filip Uhlík Changwang Pan Takeshi Akasaka Xing Lu Ludwik Adamowicz State Key Laboratory of Materials Processing and Die & Mould Technology School of Material Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China Department of Physical and Macromolecular Chemistry Faculty of Science Charles University Albertov 6 128 43 Praha 2 Czech Republic Department of Chemistry and Biochemistry University of Arizona Tucson AZ 85721-0041 USA

The very recently prepared clusterfullerene Y 2 C 2 @ C 1 (1660)-C 108 is computed and the observed structural features are confirmed, including the quasi-linear arrangement of the encapsulate and its near-triple CC bond. Its stability is explained by sizeable encapsulation energy. The endohedral stability is evaluated at both DFT and MP2 levels.

关键词： Clusterfullerenes Polyatomic encapsulates Y 2 C 2 @ C 1 (1660)-C 108 Encapsulation energetics Computational evaluations

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Synthesis of glycerol carbonate from transesterification of glycerol with dimethyl carbonate catalyzed by CaO from natural sources as green and economical catalyst

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materials Today: Proceedings 2018年第6期5卷 13909-13915页

作者： Wuttichai Roschat Sunti Phewphong Teadkait Kaewpuang Vinich Promarak School of Chemistry Institute of Science Suranaree University of Technology Nakhon Ratchasima 30000 Thailand Program of Chemistry Faculty of Science and Technology Sakon Nakhon Rajabhat University Sakon Nakhon 47000 Thailand Center of Excellence on Alternative Energy Sakon Nakhon Rajabhat University Sakon Nakhon 47000 Thailand Department of Material Science and Engineering Vidyasirimedhi Institute of Science and Technology 21210 Thailand

CaO catalysts derived from natural sources were investigated in the transesterification of dimethyl carbonate with glycerol to produce glycerol carbonate. The obtained CaO catalysts were characterized by several techniques, namely TG-DTA, XRD, XRF, BET surface area, SEM, FT-IR, CO 2 -TPD, and Hammett indicator test. The transesterification was simply monitored and analyzed by NMR technique. Under the optimized reaction conditions of dimethyl carbonate to glycerol molar ratio of 3:1, catalyst loading amount of 3 wt.% and reaction temperature of 80 °C; over 92.1% yield of glycerol carbonate product could be achieved within 2 h.

关键词： Glycerol carbonate CaO Heterogeneous catalyst Transesterification NMR analysis

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Effects of Molarity Variation on The Optical Property and Topography of ZnO Thin Films Deposited Via Spray Pyrolysis

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Journal of Physics: Conference Series 2019年第1期1191卷

作者： M B Gili R Chu M Balela Material Science and Engineering Program College of Science University of the Philippines Diliman Quezon City 1101 Philippines Philippine Nuclear Research Institute – Department of Science and Technology Commonwealth Avenue Diliman Quezon City 1101 Philippines Department of Mining Metallurgical and Materials Engineering College of Engineering University of the Philippines Diliman Quezon City 1101 Philippines

Thin film deposition is very crucial in fabricating ZnO-based electronic devices such as sensors, piezoelectric generators and photovoltaic solar cells. In this study, ZnO thin films were deposited in glass substrates via spray pyrolysis with varying zinc acetate dihydrate concentration. The films exhibited high absorption in the near-UV region (292-400 nm), yet maintaining high transmission over the visible spectra with maximum attenuation of only 33%. The optical bandgap energy of the deposited ZnO films was almost constant at around 3.25 – 3.27 eV. At higher molarity, the optical adsorption is greater especially at near-UV region while the optical transmission is lower at the visible light region. SEM images reveal that the ZnO film is composed of tiny particles. Generally, the film becomes rougher at higher zinc acetate concentration due to the formation of larger ZnO particles.

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Effects of Mechanical Activation of Precursors in The Synthesis of Ca-Doped BaTiO3 Via Conventional Solid State Reaction Method

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Journal of Physics: Conference Series 2019年第1期1191卷

作者： M B Gili R Chu R Cervera Material Science and Engineering Program College of Science University of the Philippines Diliman Quezon City 1101 Philippines Philippine Nuclear Research Institute – Department of Science and Technology Commonwealth Avenue Diliman Quezon City 1101 Philippines Department of Mining Metallurgical and Materials Engineering College of Engineering University of the Philippines Diliman Quezon City 1101 Philippines

The synthesis of pure ceramics with high degree of crystallinity is a major challenge especially in fabricating electronic devices. In this study, Ca-doped BaTiO3 with minimal impurity was successfully synthesized using conventional solid-state reaction method. The effect of mechanical activation of the precursors in the crystallinity and porosity of the material was investigated. For samples sintered at 1000 °C, the crystallite size slightly decreased from 5.410 Å to 5.288 Å which is equivalent to 2.31% reduction upon activation of precursors. At sintering temperature of 850 °C, the porosity increased from 35.985% to 39.217% with mechanical activation of the precursor powders while at 1000 °C, it jumped from 54.803% to 57.084%.

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Double-Cable Conjugated Polymers with Pendent Near-Infrared Electron Acceptors for Single-Component Organic Solar Cells

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Angewandte Chemie 2022年第35期134卷

作者： Shijie Liang Baiqiao Liu Dr. Safakath Karuthedath Jing Wang Dr. Yakun He Wen Liang Tan Hao Li Prof. Yunhua Xu Prof. Ning Li Prof. Jianhui Hou Prof. Zheng Tang Prof. Frédéric Laquai Prof. Christopher R. McNeill Prof. Christoph J. Brabec Prof. Weiwei Li Beijing Advanced Innovation Center for Soft Matter Science and Engineering & State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical Technology Beijing 100029 China Contribution: Data curation (lead) Formal analysis (lead) Investigation (equal) Writing - original draft (supporting) Writing - review & editing (supporting) Department of Chemistry School of Science Beijing Jiaotong University Beijing 100044 P. R. China KAUST Solar Center (KSC) Physical Sciences and Engineering Division (PSE) Material Science and Engineering Program (MSE) King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Kingdom of Saudi Arabia Contribution: Data curation (supporting) Formal analysis (supporting) Investigation (supporting) Writing - original draft (supporting) Writing - review & editing (supporting) Center for Advanced Low-dimension Materials College of Materials Science and Engineering Donghua University Shanghai 201620 P. R. China Contribution: Data curation (supporting) Formal analysis (supporting) Investigation (supporting) Methodology (supporting) Writing - review & editing (supporting) Institute of Materials for Electronics and Energy Technology (i-MEET) Friedrich-Alexander-Universität Erlangen-Nürnberg Martensstrasse 7 91058 Erlangen Germany Contribution: Data curation (supporting) Formal analysis (supporting) Investigation (supporting) Methodology (supporting) Writing - original draft (supporting) Writing - review & editing (supporting) Department of Materials Science and Engineering Monash University Wellington Road Clayton Victoria 3800 Australia State Key Laboratory of Polymer Physics and Chemistry Beijing National Laboratory for Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China Contribution: Data curation (supporting) Formal analysis (supporting) Writing - review & editing (supporting) Contribution: Funding acquisition (supporting) Writing - review & editing (supportin

Double-cable conjugated polymers with near-infrared (NIR) electron acceptors are synthesized for use in single-component organic solar cells (SCOSCs). Through the development of a judicious synthetic pathway, the highly sensitive nature of the 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (IC)-based electron acceptors in basic and protonic solvents is overcome. In addition, an asymmetric design motif is adopted to optimize the packing of donor and acceptor segments, enhancing charge separation efficiency. As such, the new double-cable polymers are successfully applied in SCOSCs, providing an efficiency of over 10 % with a broad photo response from 300 to 850 nm and exhibiting excellent thermal/light stability. These results demonstrate the powerful design of NIR-acceptor-based double-cable polymers and will enable SCOSCs to enter a new stage.

关键词： Double-Cable Conjugated Polymers Electron Acceptors Near Infrared Single Component Solar Cells

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Heavy anionic complex creates a unique water structure at a soft charged interface

arXiv

引用

arXiv 2018年

作者： Rock, William Qiao, Baofu Zhou, Tiecheng Clark, Aurora E. Uysal, Ahmet Argonne National Laboratory Chemical Sciences and Engineering Division United States ArgonneIL60439 United States Department of Chemistry and Material Science and Engineering Program United States Washington State University PullmanWA99164 United States

Ion hydration and interfacial water play crucial roles in numerous phenomena ranging from biological to industrial systems. Although biologically relevant (and mostly smaller) ions have been studied extensively in this context, very little experimental data exist about molecular scale behavior of heavy ions and their complexes at interfaces, especially under technologically significant conditions. It has recently been shown that PtCl62-complexes adsorb at positively charged interfaces in a two-step process that cannot fit into well-known empirical trends, such as Hofmeister series. Here, a combined vibrational sum frequency generation and molecular dynamics study reveals that a unique interfacial water structure is connected to this peculiar adsorption behavior. A novel sub-ensemble analysis of MD simulation results show that after adsorption, PtCl62-complexes partially retain their first and second hydration spheres, and it is possible to identify three different types of water molecules around them based on their orientational structures and hydrogen bonding strengths. These results have important implications for relating interfacial water structure and hydration enthalpy to the general understanding of specific ion effects. This in turn influences interpretation of heavy metal ion distribution across and reactivity within, liquid interfaces. Copyright © 2018, The Authors. All rights reserved.

关键词： Molecules

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