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Intrareticular Exciton Effects Regulate Photocatalytic Activity in Donor–Acceptor Olefin-Linked Covalent Organic Frameworks

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Small 2025年第1期21卷 e2408324页

作者： Zhang, Jie Zhou, Wenwen Zhao, Jianfeng Xu, Liangliang Jiang, Xuekai Li, Zhiwen Peng, Yongwu Li, Gao Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education Anhui University Hefei 230601 China State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China Department of Chemical and Biomolecular Engineering Korea Advanced Institute of Science and Technology Daejeon 34141 South Korea College of Materials Science and Engineering Zhejiang University of Technology Hangzhou 310014 China Institute of Catalysis for Energy and Environment College of Chemistry and Chemical Engineering Shenyang Normal University Shenyang 110034 China

Olefin-linked covalent organic frameworks (OL-COFs) show great promise for visible-light-driven photocatalysis. Manipulating atomic-level donor–acceptor interactions in OL-COFs is key to understanding their exciton effects in this system. Here, three OL-COFs are presented with orthorhombic lattice structures, synthesized via Knoevenagel polycondensation reaction of terephthalaldehyde and tetratopic monomers featuring phenyl, benzo[c][1,2,5]oxadiazole, and benzo[c][1,2,5]thiadiazole moieties. These OL-COFs feature tunable donor–acceptor interactions, making them ideal for studying exciton effects in olefin-linked systems. Comprehensive analyses, including temperature-dependent photoluminescence spectra, ultrafast spectroscopy, and theoretical calculations, reveal that stronger donor–acceptor interactions lead to reduced exciton binding energy (E_b), accelerated exciton dissociation, and longer-lived photogenerated charges, thereby enhancing photocatalytic performance. Notably, The TMO-BDA COF, with the lowest E_b, demonstrates superior photocatalytic activity in one-pot sequential organic transformation and excellent catalytic performance in gram-scale reactions, highlighting its potential for practical applications. This work provides valuable insights into regulating the exciton effect at the molecular level in OL-COFs, offering pathways to enhance photocatalytic efficiency. © 2024 Wiley-VCH GmbH.

关键词： intrareticular exciton effects olefin-linked covalent organic frameworks photo-oxidation ultrafast photocarrier dynamics

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Interfacial charge and energy transfer in van der Waals heterojunctions

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InfoMat 2022年第3期4卷 64-84页

作者： Zehua Hu Xue Liu Pedro Ludwig Hernandez-Martínez Shishu Zhang Peng Gu Wei Du Weigao Xu Hilmi Volkan Demir Haiyun Liu Qihua Xiong Division of Physics and Applied Physics School of Physical and Mathematical SciencesNanyang Technological UniversitySingaporeSingapore Institutes of Physical Science and Information Technology Anhui UniversityHefeiP.R.China LUMINOUS Center of Excellence for Semiconductor Lighting and DisplaySchool of Electrical and Electronics EngineeringNanyang Technological UniversitySingaporeSingapore State Key Laboratory of Low-Dimensional Quantum Physics Department of PhysicsTsinghua UniversityBeijingP.R.China Beijing Academy of Quantum Information Sciences BeijingP.R.China Institute of Functional Nano and Soft Materials(FUNSOM) Soochow UniversitySuzhouP.R.China Key Laboratory of Mesoscopic Chemistry of MOE School of Chemistry and Chemical EngineeringNanjing UniversityNanjingP.R.China Department of Physics Department of Electrical and Electronics EngineeringUNAM-National Nanotechnology Research Center and Institute of Materials Science and NanotechnologyBilkent UniversityAnkaraTurkey Beijing Innovation Center for Future Chips Tsinghua UniversityBeijingP.R.China

Van der Waals heterojunctions are fast-emerging quantum structures fabricated by the controlled stacking of two-dimensional(2D)*** to the atomically thin thickness,their carrier properties are not only determined by the host material itself,but also defined by the interlayer interactions,including dielectric environment,charge trapping centers,and stacking *** abundant constituents without the limitation of lattice constant matching enable fascinating electrical,optical,and magnetic properties in van der Waals heterojunctions toward next-generation devices in photonics,optoelectronics,and information *** review focuses on the charge and energy transfer processes and their dynamics in transition metal dichalcogenides(TMDCs),a family of quantum materials with strong excitonic effects and unique valley properties,and other related 2D materials such as graphene and hexagonalboron *** the first part,we summarize the ultrafast charge transfer processes in van der Waals heterojunctions,including its experimental evidence and theoretical understanding,the interlayer excitons at the TMDC interfaces,and the hot carrier injection at the graphene/TMDCs *** the second part,the energy transfer,including both Förster and Dexter types,are reviewed from both experimental and theoretical ***,we highlight the typical charge and energy transfer applications in photodetectors and summarize the challenges and opportunities for future development in this field.

关键词： 2-dimensional semiconductors carrier dynamics charge and energy transfer optical spectroscopy optoelectronics

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Prediction of giant tunneling magnetoresistance in RuO2/TiO2/RuO2 (110) antiferromagnetic tunnel junctions

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physical Review B 2023年第17期108卷 174439-174439页

作者： Yuan-Yuan Jiang Zi-An Wang Kartik Samanta Shu-Hui Zhang Rui-Chun Xiao W. J. Lu Y. P. Sun Evgeny Y. Tsymbal Ding-Fu Shao Key Laboratory of Materials Physics Institute of Solid State Physics HFIPS Chinese Academy of Sciences Hefei 230031 China Science Island Branch of Graduate School University of Science and Technology of China Hefei 230026 China Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience University of Nebraska Lincoln Nebraska 68588-0299 USA College of Mathematics and Physics Beijing University of Chemical Technology Beijing 100029 People's Republic of China Institute of Physical Science and Information Technology Anhui University Hefei 230601 China High Magnetic Field Laboratory HFIPS Chinese Academy of Sciences Hefei 230031 China Collaborative Innovation Center of Microstructures Nanjing University Nanjing 210093 China

Using first-principles quantum-transport calculations, we investigate spin-dependent electronic and transport properties of antiferromagnetic tunnel junctions (AFMTJs) that consist of (110)-oriented antiferromagnetic (AFM) metal RuO2 electrodes and an insulating TiO2 tunneling barrier. We predict the emergence of a giant tunneling magnetoresistance (TMR) effect in a wide energy window, a series of barrier layer thicknesses, and different interface terminations, indicating the robustness of this effect. We show that the predicted TMR cannot be explained in terms of the global transport spin-polarization of RuO2 (110) but is well understood based on matching the momentum-dependent spin-polarized conduction channels of the two RuO2 (110) electrodes. We predict oscillations of TMR with increasing barrier thickness, indicating a non-negligible contribution from the perfectly epitaxial interfaces. Our work helps the understanding of the physics of TMR in AFMTJs and aids in realizing efficient AFM spintronic devices.

关键词： Spin current Spintronics Antiferromagnets Magnetic tunnel junctions First-principles calculations

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Accelerating C_(2+)alcohols synthesis from syngas by simultaneous optimizations of CO dissociation and chain growth over CuCo alloy catalyst

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Chinese chemical Letters 2021年第7期32卷 2203-2206页

作者： Meiling Shui Chao Huang Peiyu Ma Wenjie Li Qun He Wenlong Wu Yisheng Tan Jun Bao National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029China Hefei National Laboratory for Physical Sciences at the Microscale Key Laboratory of Strongly-Coupled Quantum Matter Physics of Chinese Academy of SciencesKey Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education InstitutesDepartment of Chemical PhysicsUniversity of Science and Technology of ChinaHefei 230026China State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China

With regard to the reaction of higheralcohol synthesis(HAS),the optimizations of activity and selectivity towards C_(2+)alcohol are restricted by the improper equilibrium in two different CO activation pathways and chain growth ***,we find that delibrately controlling the compositions of catalysts is an effective strategy to achieve the equilibrium of CO activation pathways and promote the chain *** a result,the optimized Cu_(0.25)Co_(0.75) alloy catalyst can achieve a large proportion of higher alcohol in alcohol products(C_(2+)OH/MeOH=4.40),together with high CO conversion of 71.27%and space-time-yield of 147.65 g kg^(-1) h^(-1).The mechanistic studies suggest that the good performance of Cu_(0.25)Co_(0.75) catalyst is attributed to the synergistic effect between alloyed Cu and Co.

关键词： CuCo alloy Syngas C_(2+)alcohols CO activation Synergistic effect

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Construction of hollow mesoporous silica nanoreactors for enhanced photo-oxidations over Au-Pt catalysts

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National science Review 2020年第11期7卷 1647-1655页

作者： Hao Tian Jinhui Zhao Xinyao Wang Lizhuo Wang Hao Liu Guoxiu Wang Jun Huang Jian Liu G.Q.(Max) Lu State Key Laboratory of Catalysis Dalian Institute of Chemical Physics (DICP)Chinese Academy of Sciences Centre for Clean Energy Technology School of Mathematical and Physical SciencesFaculty of ScienceUniversity of Technology Sydney Laboratory for Catalysis Engineering School of Chemical and Biomolecular Engineering Sydney Nano Institute The University of Sydney DICP-Surrey Joint Centre for Future Materials Department of Chemical and Process Engineering and Advanced Technology Institute University of Surrey University of Surrey

It is highly desirable to design hollow structures with multi-scale functions by mimicking cells for the construction of micro/nanoreactors. Herein, we report the construction of hollow-structured submicrometer-photoreactors with bimetallic catalysts loaded within mesoporous silicas. The synthesis parameters are optimized to study the evolution of hollow structure through hydrothermal treatment and an ‘adhesive-contraction’ formation mechanism is proposed. Au Pt@HMZS catalysts exhibited a broader absorbance region under visible light and the adsorption edge displayed a red-shift, indicating the strong metal–metal interactions at the alloy interface. The reaction performance of the coupled Au-Pt catalysts can be tuned to achieve excellent catalytic activity in cinnamyl alcohol oxidation to cinnamic acid for 3.1 mmol g-1with 99%selectivity. The proposed strategy to build hollow structures as multifunctional micro/nanoreactors is promising for the design of high-performance and sustainable catalysts for chemical synthesis.

关键词： nanoreactors photocatalytic oxidation metal nanoparticles mesoporous materials surface plasmonic resonance

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Synthesis of Iron-Carbide Nanoparticles:Identification of the Active Phase and Mechanism of Fe-Based Fischer-Tropsch Synthesis

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CCS Chemistry 2021年第11期3卷 2712-2724页

作者： Huabo Zhao Jin-Xun Liu Ce Yang Siyu Yao Hai-Yan Su Zirui Gao Mei Dong Junhu Wang Alexandre I.Rykov Jianguo Wang Yanglong Hou Wei-Xue Li Ding Ma College of Chemistry and Molecular Engineering Peking UniversityBeijing 100871 Department of Chemical Physics School of Chemistry and Materials ScienceHefei National Laboratory for Physical Sciences at the MicroscaleiCHEMUniversity of Science and Technology of ChinaHefei 230026 Department of Materials Science and Engineering College of EngineeringPeking UniversityBeijing 100871 School of Chemical Engineering and Energy Technology Dongguan University of TechnologyDongguan 523808 State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001 Center for Advanced Mössbauer Spectroscopy Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023

Despite the extensive study of the Fe-based Fischer-Tropsch synthesis(FTS)over the past 90 years,its active phases and reaction mechanisms are still unclear due to the coexistence of metals,oxides,and carbide phases presented under realistic FTS reaction conditions and the complex reaction network involving CO activation,C-C coupling,and methane *** address these issues,we successfully synthesized a range of pure-phase iron and iron-carbide nanoparticles(Fe,Fe_(5)C_(2),Fe_(3)C,and Fe_(7)C_(3))for the first *** using them as the ideal model catalysts on high-pressure transient experiments,we identified unambiguously that all the iron carbides are catalytically active in the FTS reaction while Fe_(5)C_(2) is the most active yet stable carbide phase,consistent with density functional theory(DFT)calculation *** reaction mechanism and kinetics of Fe-based FTS were further explored on the basis of those model catalysts by means of transient high-pressure stepwise temperature-programmed surface reaction(STPSR)experiments and DFT *** work provides new insights into the active phase of iron carbides and corresponding FTS reaction mechanism,which is essential for better iron-based catalyst design for FTS reactions.

关键词： Fischer-Tropsch synthesis iron carbides active phase reaction mechanism

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Polymer dynamics under tension: Mean first passage time for looping

arXiv

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arXiv 2024年

作者： Laeremans, Wout den Ouden, Anne Floor Hooyberghs, Jef Ellenbroek, Wouter G. Soft Matter and Biological Physics Department of Applied Physics and Science Education Institute for Complex Molecular Systems Eindhoven University of Technology P.O. Box 513 Eindhoven5600 MB Netherlands Laboratory of Physical Chemistry Department of Chemical Engineering and Chemistry Eindhoven University of Technology P.O. Box 513 Eindhoven5600 MB Netherlands UHasselt Faculty of Sciences Data Science Institute Theory Lab Agoralaan Diepenbeek3590 Belgium

This study deals with polymer looping, an important process in many chemical and biological systems. We investigate basic questions on the looping dynamics of a polymer under tension using the freely-jointed chain (FJC) model. Previous theoretical approaches to polymer looping under tension have relied on barrier escape methods, which assume local equilibrium, an assumption that may not always hold. As a starting point we use an analytical expression for the equilibrium looping probability as a function of the number of monomers and applied force, predicting an inverse relationship between looping time and looping probability. Using molecular dynamics simulations the predictions of this theoretical approach are validated within the numerical precision achieved. We compare our predictions to those of the barrier escape approach, by way of a calculation of the mean first passage time (MFPT) for the ends of a polymer to cross. For this purpose, we derive the exact free energy landscape, but resulting temporal predictions do not agree with the observed inverse scaling. We conclude that the traditional barrier escape approach does not provide satisfactory predictions for polymer looping dynamics and that the inverse scaling with looping probability offers a more reliable alternative. Copyright © 2024, The Authors. All rights reserved.

关键词： Inverse problems

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Unveiling upsurge of photogenerated ROS: control of intersystem crossing through tuning aggregation patterns

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chemical science 2022年第2期14卷 323-330页

作者： Wang, Junjun Li, Hao Zhu, Yicai Yang, Mingdi Huang, Jing Zhu, Xiaojiao Yu, Zhi-Peng Lu, Zhou Zhou, Hongping School of Chemistry and Chemical Engineering Institute of Physical Science and Information Technology Anhui University and Key Laboratory of Functional Inorganic Materials Chemistry of Anhui Province Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials Key Laboratory of Structure and Functional Regulation of Hybrid Materials (Anhui University) Ministry of Education Hefei 230601 China Anhui Province Key Laboratory of Optoelectronic Material Science and Technology School of Physics and Electronic Information Anhui Normal University Wuhu 241002 China School of Materials and Chemical Engineering Anhui Jianzhu University Hefei 230601 China

Photo-induced reactive oxygen species (ROS) generation by organic photosensitizers (PSs), which show potential in significant fields such as photodynamic therapy (PDT), are highly dependent on the formation of the excited triplet state through intersystem crossing (ISC). The current research on ISC of organic PSs generally focuses on molecular structure optimization. In this manuscript, the influence of aggregation patterns on ISC was investigated by constructing homologous monomers (S-TPA-PI and L-TPA-PI) and their homologous dimers (S-2TPA-2PI and L-2TPA-2PI). In contrast to J-aggregated S-TPA-PI, S-2TPA-2PI-aggregate forming “end-to-end” stacking through π-π interaction could generate ROS more efficiently, due to a prolonged exciton lifetime and enhanced ISC rate constant (k_ISC), which were revealed by femtosecond transient absorption spectroscopy and theoretical calculations. This finding was further validated by the regulation of aggregation patterns induced by host-guest interaction. Moreover, S-2TPA-2PI could target mitochondria and achieve rapid mitophagy to cause more significant cancer cell suppression. Overall, the delicate supramolecular dimerization tactics not only revealed the structure-property relationship of organic PSs but also shed light on the development of a universal strategy in future PDT and photocatalysis fields. © 2023 The Royal Society of Chemistry.

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Electrically tunable layer-hybridized trions in doped WSe2 bilayers

arXiv

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arXiv 2024年

作者： Perea-Causin, Raul Brem, Samuel Buchner, Fabian Lu, Yao Watanabe, Kenji Taniguchi, Takashi Lupton, John M. Lin, Kai-Qiang Malic, Ermin Department of Physics Chalmers University of Technology Gothenburg Sweden Department of Physics Stockholm University Stockholm Sweden Department of Physics Philipps-Universität Marburg Marburg Germany Department of Physics University of Regensburg Regensburg Germany State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical Engineering Xiamen University Xiamen China Research Center for Electronic and Optical Materials National Institute for Materials Science Tsukuba Japan Research Center for Materials Nanoarchitectonics National Institute for Materials Science Tsukuba Japan

Doped van der Waals heterostructures host layer-hybridized trions, i.e. charged excitons with layerdelocalized constituents holding promise for highly controllable optoelectronics. Combining a microscopic theory with photoluminescence (PL) experiments, we demonstrate the electrical tunability of the trion energy landscape in naturally stacked WSe2 bilayers. We show that an out-of-plane electric field modifies the energetic ordering of the lowest lying trion states, which consist of layer-hybridized Λ-point electrons and layer-localized K-point holes. At small fields, intralayer-like trions yield distinct PL signatures in opposite doping regimes characterized by weak Stark shifts in both cases. Above a doping-asymmetric critical field, interlayer-like species are energetically favored and produce PL peaks with a pronounced Stark red-shift and a counter-intuitively large intensity arising from efficient phonon-assisted recombination. Our work presents an important step forward in the microscopic understanding of layer-hybridized trions in van der Waals heterostructures and paves the way towards optoelectronic applications based on electrically controllable atomically-thin semiconductors. Copyright © 2024, The Authors. All rights reserved.

关键词： Van der Waals forces

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Competition of electronic correlation and reconstruction in La1−xSrxTiO3/SrTiO3 heterostructures

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physical Review B 2023年第15期108卷 155432-155432页

作者： Xueyan Wang Lin Sun Chen Ye Zhen Huang Kun Han Ke Huang Allen Jian Yang Shengwei Zeng Xian Jun Loh Qiang Zhu T. Venkatesan A. Ariando X. Renshaw Wang School of Physical and Mathematical Sciences Nanyang Technological University 637371 Singapore Department of Physics National University of Singapore 117411 Singapore Institutes of Physical Science and Information Technology Anhui University Hefei Anhui 230601 China Institute of Materials Research and Engineering (IMRE) Agency for Science Technology and Research (A*STAR) 138634 Singapore Institute of Sustainability for Chemicals Energy and Environment (ISCE2) Agency for Science Technology and Research (A*STAR) 627833 Singapore School of Chemistry Chemical Engineering and Biotechnology Nanyang Technological University 637371 Singapore Center for Quantum Research and Technology University of Oklahoma Norman Oklahoma 73019 USA School of Electrical and Electronic Engineering Nanyang Technological University 639798 Singapore

Electronic correlation and reconstruction are two important factors that play a critical role in shaping the magnetic and electronic properties of correlated low-dimensional systems. Here, we report a competition between the electronic correlation and structural reconstruction in La1−xSrxTiO3/SrTiO3 heterostructures by modulating material polarity and interfacial strain, respectively. The heterostructures exhibit a critical thickness (tc) at which a metal to insulator transition abruptly occurs at certain thickness, accompanied by the coexistence of two- and three-dimensional (2D and 3D) carriers. Intriguingly, the tc exhibits a V−shaped dependence on the doping concentration of Sr, with the smallest tc value at x=0.5. We attribute this V−shaped dependence to the competition between the electronic reconstruction (modulated by the polarity) and the electronic correlation (modulated by strain), which are borne out by the experimental results, including strain-dependent electronic properties and the evolution of 2D and 3D carriers. Our findings underscore the significance of the interplay between electronic reconstruction and correlation in the realization and utilization of emergent electronic functionalities in low-dimensional correlated systems.

关键词： Metal-insulator transition Surface reconstruction Transport phenomena Thin films Transition metal oxides

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