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On the half-quantized Hall conductance of massive surface electrons in magnetic topological insulator films

Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 127-136页

作者： Rui Chen Shun-qing shen Department of Physics The University of Hong KongHong Kong 999077China Department of Physics Hubei UniversityWuhan 430062China

In topological insulators,massive surface states resulting from local symmetry breaking were thought to exhibit a half-quantized Hall conductance,obtained from the low-energy effective model in an infinite Brillouin zone.In a lattice model,the surface band is composed of a combination of surface states and bulk states.The massive surface states alone may not be enough to support an exact one-half quantized surface Hall conductance in a finite Brillouin zone and the whole surface band always gives an integer quantized Hall conductance as enforced by the TKNN theorem.To explore this,we investigate the band structures of a lattice model describing the magnetic topological insulator film that supports the axion insulator,Chern insulator,and semi-magnetic topological insulator phases.We reveal that the gapped and gapless surface bands in the three phases are characterized by an integer-quantized Hall conductance and a half-quantized Hall conductance,respectively.We propose an effective model to describe the three phases and show that the low-energy dispersion of the surface bands inherits from the surface Dirac fermions.The gapped surface band manifests a nearly half-quantized Hall conductance at low energy near the center of Brillouin zone,but is compensated by another nearly half-quantized Hall conductance at high energy near the boundary of Brillouin zone because a single band can only have an integer-quantized Hall conductance.The gapless band hosts a zero Hall conductance at low energy but is compensated by another half-quantized Hall conductance at high energy,and thus the half-quantized Hall conductance can only originate from the gapless band.Moreover,we calculate the layer-resolved Hall conductance of the system.The conclusion suggests that the individual gapped surface band alone does not support the half-quantized surface Hall effect in a lattice model.

关键词： magnetic topological insulator Dirac equation half-quantized Hall conductance

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How to get high-efficiency lead chalcogenide quantum dot solar cells?

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Science China(Physics,Mechanics & Astronomy) 2023年第1期66卷 34-59页

作者： Chao Ding qing shen Faculty of Informatics and Engineering The University of Electro-CommunicationsTokyo 182-8585Japan

Lead chalcogenide colloidal quantum dots(CQDs)are regarded as attractive absorption materials for novel solar cells(SCs).The cost of lead chalcogenide CQD has been decreased to a commercialization target of$5/g due to the direct production of CQD inks.However,the photoelectric conversion efficiency(PCE)of lead chalcogenide CQDSCs is presently close to 14%,well below the commercialization target(20%),which is only 41%of the theoretical Shockley-Queisser limit efficiency.In this study,the different losses of open-circuit voltage(V_(oc)),fill factor(FF),and short circuit current density(J_(sc))for current CQDSCs are systematically discussed,as well as the percentage and likely causes of each loss.Then the primary reasons for the CQDSCs’performance constraints are highlighted.Following that,we focus on the CQDSCs interfaces(i.e.,CQD/CQD,CQD/HTL,and ETL/CQD)and explore viable ways to reduce device performance loss.Finally,based on the discussion above,we propose many enhancements to significantly solve numerous major obstacles impeding device performance to boost the PCE of CQDSCs for future commercialization significantly.

关键词： lead chalcogenide colloidal quantum dots solar cell interface engineering non-radiative carrier recombination charge carrier transport losses

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Visible Light-Driven Catalyst-Free Amination of Indoles Initiated by Electron Donor-Acceptor Complexes

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Chinese Journal of Chemistry 2023年第12期41卷 1485-1490页

作者： Jiahong Sui Zhonglie Yang Shuangqiao Li Xueqin Chen Xiaobin Zhang qing shen Hezhong Jiang Jiahong Li School of Life Science and Engineering Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs Southwest Jiaotong University Chengdu Sichuan 610031 China Department of Pharmacy Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital/Personalized Drug Therapy Key Laboratory of Sichuan Province School of Medicine University of Electronic Science and Technology of China Chengdu Sichuan 610072 China

The visible light-driven C2 or C3 amination of indoles without any additives was initiated via electron donor-acceptor (EDA) complex formed by indole and N-aminopyridinium salt.This method was compatible with a wide range of substrates and could proceed smoothly without the addition of any photocatalysts,transition-metal catalysts,or bases.A variety of studies were carried out to examine the presence of EDA complex.

关键词： Photochemistry Amination C-N bond formation Green chemistry N-Heterocycles Donor-acceptor systems

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Light-responsive organic artificial enzymes:Material designs and bio-applications

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Nano Research 2023年第1期16卷 117-126页

作者： Weili Wang qing shen Hao Cai Leichen Wang Jinjun Shao Wenjun Wang Xiaochen Dong Key Laboratory of Flexible Electronics(KLOFE)and Institute of Advanced Materials(IAM) Nanjing Tech University(NanjingTech)Nanjing 211816China School of Physical Science and Information Technology Liaocheng UniversityLiaocheng 252059China

As significant biocatalysts,natural enzymes have exhibited a vast range of applications in biocatalytic reactions.However,the“always-on”natural enzyme activity is not beneficial for the regulation of catalytic processes,which limits their bio-applications.Recently,it has been extensively reported that various organic artificial enzymes exhibit prominent absorption and controlled activity under illumination,which not only creates a series of light-responsive catalytic platforms but also plays a key role in biosensing and biomedical research.To provide novel ideas for the design of artificial enzymes,we conduct this review to highlight the recent progress of light-responsive organic artificial enzymes(LOA-Enz).The specific photoresponse mechanism and various bio-applications of LOA-Enz are also presented in detail.Furthermore,the remaining challenges and future perspectives in this field are discussed.

关键词： light-response organic artificial enzymes catalytic activity bio-applications

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何谓机器?——基于德勒兹思想的再理解

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湖北大学学报（哲学社会科学版） 2024年第3期51卷 89-96页

作者：沈清容西南大学马克思主义学院重庆400715

德勒兹对机器的阐发为我们全面理解机器提供了一种新的可能和示范。不同于传统对机器的阐释,德勒兹一方面反对将机器纳入机械论、有机论或决定论的范畴,另一方面他力图超越机器科学论,并与马克思所描述的工业革命的机器保持距离。在德... 详细信息

德勒兹对机器的阐发为我们全面理解机器提供了一种新的可能和示范。不同于传统对机器的阐释,德勒兹一方面反对将机器纳入机械论、有机论或决定论的范畴,另一方面他力图超越机器科学论,并与马克思所描述的工业革命的机器保持距离。在德勒兹的观念中,机器不具有任何的隐喻意义,机器从来都不只单纯地拘泥于技术性并为技术所涵括;相反,机器的技术性恰恰源自其社会性。对于德勒兹来说,任何机器都是配置或集体装置中的机器。在德勒兹的表述中,机器不是一个概念,而是一套实践,即一个连接和异质性的实践。德勒兹对机器进行研究不仅丰富了我们对机器的认识,也为我们理解机器本身提供了一个全新的视角。

关键词：德勒兹机器集合体社会控制技术

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Design of Non-fused Ring Acceptors toward High-Performance,Stable,and Low-Cost Organic Photovoltaics

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Accounts of Materials Research 2022年第6期3卷 644-657页

作者： qing shen Chengliang He Shuixing Li Lijian Zuo Minmin Shi Hongzheng Chen State Key Laboratory of Silicon Materials MOE Key Laboratory of Macromolecular Synthesis and FunctionalizationInternational Research Center for X PolymersDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027P.R.China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Hangzhou 310027P.R.China

Toward future commercial applications of organic solar cells(OSCs),organic photovoltaic materials that enable high efficiency,excellent stability,and low cost should be developed.Fused-ring electron acceptors(FREAs)have declared that OSCs are capable of showing efficiencies over 19%,whereas stability and cost are not solved yet.As the counterparts of FREAs,non-fused ring electron acceptors(NFREAs)are more flexible in molecular design.They have better stability because of the reduction of intramolecular tension via breaking fused backbone and have more advantages in cost with the reduction of synthetic complexity.However,the challenge for NFREAs is the relatively lower efficiencies(around 15%at current stage),which require better molecular designs for addressing the issues of conformational unicity and effective molecular packing.In this Account,we comprehensively summarize works about NFREAs carried out in our group from three main frameworks,including molecular design and efficiency optimization,material cost,and stability.First,in the part of molecular design and efficiency optimization,the existing rotatable single bond in NFREAs will bring the problem of conformational uncertainty,but it can be solved through proper molecular design,which also regulates the energy levels,light absorption range,and the packing mode of the molecule for obtaining higher performance.Thus,in this part,we discuss the evolution of NFREAs in three aspects,including molecular skeleton optimization,terminal modification,and side chain engineering.Many strategies are used in the design of a molecular skeleton,such as utilizing the quinoid effect,introducing functional groups with the electron push−pulling effect,and using multiple conformational lock.Furthermore,simplifying the skeleton is also the preferred development tendency.As for the terminal,the main modification strategy is adjusting the conjugation length and halogen atoms.What is more,by adjusting the side chain to induce appropriate steric hindrance,we can fix the orientation

关键词： stability fused stability

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Promoted intramolecular photoinduced-electron transfer for multi-mode imaging-guided cancer photothermal therapy

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Rare Metals 2022年第1期41卷 56-66页

作者： Xin-Yu Qu Ying Hong Han Cai Xu Sun qing shen Dong-Liang Yang Xiao-Chen Dong Ai-Hong Jiao Peng Chen Jin-Jun Shao Key Laboratory of Flexible Electronics and Institute of Advanced Materials Nanjing Tech UniversityNanjing 211800China Nanjing University of Information Science and Technology Nanjing 210044China Yuhuangding Hospital of qingdao University Yantai 264000China School of Chemical and Biomedical Engineering Nanyang Technological UniversitySingapore 637459Singapore

To develop smart and efficient near-infrared(NIR)organic dyes for photothermal cancer therapy is of great challenge.Herein,a pH-sensitive NIR dye BTN with donor–acceptor–donor scaffold has been synthesized.Two periphery electron-donating dimethylamine groups in BTN can not only promote the intramolecular photoinduced electron transfer(PET),but also bind protons to transform into electron-deficient ammonium cation for enhanced intramolecular charge transfer(ICT)under acidic circumstance.Through enveloping with amphiphilic polymeric 1,2-distearoyl-ras-glycerol-3-phosphatidyl ethanolamine-N-polyethyleneglycol-2000(DSPE-mPEG2000),BTN nanoparticles(NPs)were fabricated with robust NIR absorption covering 600–900 nm,excellent photothermal conversion efficiency(43.2%),and good photostability.Additionally,BTN NPs can selectively target lysosomes.Through tailing intravenous injection into tumor-bearing nude mice,BTN NPs demonstrate outstanding photoacoustic/photothermal/fluorescence imaging-guided photothermal therapy for tumor ablation.

关键词： Photothermal Phototherapy Near-infrared dye Photoinduced-electron transfer Intramolecular charge transfer

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Characterization of hot carrier cooling and multiple exciton generation dynamics in PbS QDs using an improved transient grating technique

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Journal of Energy Chemistry 2015年第6期24卷 712-716页

作者： qing shen Kenji Katayama Taro Toyoda Department of Engineering Science Faculty of Informatics and EngineeringThe University of Electro-Communications Department of Applied Chemistry Faculty of Science and EngineeringChuo University

Multiple exciton generation （MEG） dynamics in colloidal PbS quantum dots （QDs） characterized with an im- proved transient grating （TG） technique will be reported. Only one peak soon after optical absorption and a fast decay within 1 ps can be observed in the TG kinetics when the photon energy of the pump light hv is smaller than 2.7Eg （Eg： band gap between LUMO and HOMO in the QDs）, which corresponds to hot carrier cooling. When hv is greater than 2.7Eg, however, after the initial peak, the TG signal decreases first and soon increases, and then a new peak appears at about 2 to 3 ps. The initial peak and the new peak correspond to hot carriers at the higher excited state and MEG at the lowest excited state, respectively. By proposing a theoretical model, we can calculate the hot carrier cooling time constant and MEG occurrence time constant quantitatively. When MEG does not happen for hv smaller than 2.7Eg, hot carrier cools with a time con- stant of 400 fs. When MEG occurs for hv larger than 2.7Eg, hot carrier cools with a time constant as small as 200 fs, while MEG occurs with a time constant of 600 fs. The detailed hot carrier cooling and MEG occurrence dynamics characterized in this work would shed light on the further understanding of MEG mechanism of various type of semiconductor QDs.

关键词： PbS Quantum dots Multiple exciton generation Hot carrier cooling Transient grating

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Influence of charge transport layer on the crystallinity and charge extraction of pure tin-based halide perovskite film

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Journal of Energy Chemistry 2022年第6期31卷 612-615,I0017页

作者： Yaohong Zhang Muhammad Akmal Kamarudin Qiao Li Chao Ding Yong Zhou Yingfang Yao Zhigang Zou Satoshi Iikubo Takashi Minemoto Kenji Yoshino Shuzi Hayase qing shen School of Physics Northwest UniversityXi'an 710127China Faculty of Informatics and Engineering The University of Electro-CommunicationsTokyo 182-8585Japan Eco-materials and Renewable Energy Research Center Jiangsu Key Laboratory for Nano TechnologyNanjing UniversityNanjing 210093China Department of Advanced Materials Science and Engineering Faculty of Engineering SciencesKyushu UniversityFukuoka 819-0395Japan Department of Electrical and Electronic Engineering Faculty of Science and EngineeringRitsumeikan UniversityShiga 525-8577Japan Department of Electrical and Electronic Engineering Miyazaki UniversityMiyazaki 889-2192Japan

As one of the most compelling photovoltaic devices, halide perovskite (PVK) solar cells have achieved a new surprising record power conversion efficiency (PCE) of 25.8%in 2021 [1]. This demonstrates the great potential of halide PVK solar cells as a highly competitive substitute to replace silicon-based solar cells in the photovoltaic market [2–6].

关键词： Tin-based halide perovskite Charge transport layers Crystallinity Charge extraction Photoexcited carrier dynamics

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吸气式电推进系统进气道气体流动数值分析

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中国科学：物理学、力学、天文学 2024年第3期54卷 146-157页

作者：靳旭红程晓丽沈清艾邦成中国航天空气动力技术研究院北京100074 清华大学航天航空学院北京100084 中国航天科技集团有限公司航天飞行器热防护实验室北京100074

针对上层大气层吸气式电推进系统进气道的宽范围设计难题,采用直接模拟Monte Carlo(Direct Simulation Monte Carlo,DSMC)方法对进气道内部流动问题进行了系统的数值模拟,探索气体压力和质量通量的分布特征,考虑飞行高度的影响规律和作... 详细信息

针对上层大气层吸气式电推进系统进气道的宽范围设计难题,采用直接模拟Monte Carlo(Direct Simulation Monte Carlo,DSMC)方法对进气道内部流动问题进行了系统的数值模拟,探索气体压力和质量通量的分布特征,考虑飞行高度的影响规律和作用机理,评估自由分子流假设的有效性.结果表明,随着飞行高度的升高,进气道内部的无量纲压力逐渐降低,表明进气道的压缩性能减弱.因此,当吸气式电推进系统运行在上层大气层的较高区域时,应特别留意进气道的压缩性能.此外,随着飞行高度的升高,气体分子之间碰撞的减弱导致无量纲质量通量在压缩段中心区域减小,在电离加速段中部增大.对于120 km左右的高度,进气道流动中气体分子之间的碰撞仍然具有举足轻重的作用,自由分子流假设给出的气体压力和质量通量与标准DSMC结果存在明显的差异.对于180 km及以上的高度,进气道流动可以认为是自由分子流,即气体分子之间的碰撞可以忽略,自由分子流假设给出的气体压力和质量通量与标准DSMC结果一致,此时采用自由分子流假设是合理的.

关键词：上层大气层吸气式电推进进气道自由分子流 DSMC

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