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Effects of water molecules on luminescence in europium and terbium coordination polymers with p-fluorobenzoic acid as ligand

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Journal of Rare Earths 2024年第7期42卷 1258-1264页

作者： Xiaoqi Zhao Puyan Hao Yami Ling Mengzhen Jia Rui Zhu Jiawen Liu Qiang Xu Jianhong Zhou Collaborative Innovation Center of Rare-Earth Optical Functional Materials and Devices Development Baoji Key Laboratory of Micro-Nano Optoelectronics and Terahertz TechnologySchool of Physics and Opto-Electronic TechnologyBaoji University of Arts and Sciences

Our previous experimental observations show that the crystal structure of lanthanide luminescent complexes synthesized in aqueous solution usually contains a large number of coordination water molecules or free water molecules.In order to probe the influence of water molecules on luminescent processes of lanthanide complexes,the photoluminescence properties of Ln-FBA（Ln=Eu and Tb,FBA=p-fluorobenzoic acid） coordination polymers at different ambient temperatures,in different solvents and aqueous DMSO solutions with different volume concentrations were systematically investigated.The experiment results show that the presence of water molecules can promote the energy transfer from FBA ligand to Ln3+,at the same time,can cause luminescent non-radiation quenching of lanthanide ions.In addition,the variation of emission intensity ratio of 615 nm/591 nm peaks of Eu3+with increasing the volume concentration of H2O can be potentially used for the quantitatively detection of water traces in organic solve nts.In order to suppress the non-radiation quenching caused by the water molecules,Ln-FBA（Ln=Eu and Tb） coordination polymers were embedded into the PVP matrix to prepare Ln-FBA@PVP hybrid materials.The photoluminescence investigation indicates that PVP can not only block the quenching effect of water molecules on luminescence,but also effectively sensitize Eu3+and Tb3+luminescence.These experimental conclusions are useful for probing the influence of water molecules on luminescent processes of lanthanide complexes,quantitatively detecting water traces in organic solvents and enhancing the photoluminescence intensity in lanthanide complexes.

关键词： Lanthanide complexes Luminescent quenching Photoluminescence Rare earths

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Oligomeric donor with appropriate crystallinity for organic solar cells

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Chinese Chemical Letters 2024年第2期35卷 289-294页

作者： Kaiming Yang Min Lv Yanhong Chang Kun Lu Zhixiang Wei CAS key laboratory of nanosystem and Hierarchical fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China University of Chinese Academy of sciences Beijing 100049China Department of Environmental science and Engineering University of Science and Technology BeijingBeijing 100083China Beijing key laboratory of Resource Treatment of Typical Industrial Pollutants Beijing 100083China

Improving the performance of all-small-molecule organic solar cells(ASM-OSCs)largely depends on the design and application of novel donors with appropriate crystallinity.Extending molecular conjugation is an effective method for regulating molecular stacking and crystallinity.In this work,we successfully designed and synthesized two novel acceptor-donor-donor-donor-acceptor(A-D-D-D-A)type oligomeric donors with three dithieno[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b']dithiophene(DTBDT)as the central unit,named as 3DTBDT-Cl and 3DTBDT,depending on with and without chlorine substitution on the thiophene side chains.We found that the introduction of chlorine atoms makes the blend films display stronger crystallinity but with large-scale phase separation morphology and more defects,which eventually leads to a power conversion efficiency(PCE)of only 10.83%,whereas the blend films based 3DTBDT with appropriate crystallinity achieved 13.74%PCE.Compared with 3DTBDT-Cl/L8-BO,the 3DTBDT/L8-BO films exhibited a nanoscale bi-continuous interpenetrating network morphology with a smaller domain size and more suitable crystallinity,which guarantees the corresponding devices obtained more efficient exciton dissociation,efficient charge transport,reduced bimolecular recombination,and performed more balanced carrier mobility.These results demonstrated that regulating the crystallinity of oligomeric donors to obtain the desired phase separation morphology in the blend films could facilitate further improving the performance of ASM-OSCs.

关键词： Linked donor unit Oligomeric donors Crystallinity regulation Organic solar cells

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Localization effect in single crystal of RuAs2

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Chinese Physics B 2024年第4期33卷 620-625页

作者：易哲铠刘琪光双魁徐升岳小宇梁慧李娜周颖吴丹丹孙燕李秋菊程鹏夏天龙孙学峰王义炎 Anhui key laboratory of Magnetic Functional Materials and Devices Institute of Physical Science and Information TechnologyAnhui University Department of Physics and key laboratory of Strongly-Coupled Quantum Matter Physics (CAS) University of Science and Technology of China Department of Physics and Beijing key laboratory of Opto-electronic Functional Materials & micro-nano Devices Renmin University of China School of Optical and Electronic Information Suzhou City University School of Physics and Optoelectronic Engineering Anhui University Collaborative Innovation Center of Advanced microstructures Nanjing University

We report the magnetotransport and thermal properties of RuAs2single crystal. RuAs2exhibits semiconductor behavior and localization effect. The crossover from normal state to diffusive transport in the weak localization（WL） state and then to variable range hopping（VRH） transport in the strong localization state has been observed. The transitions can be reflected in the measurement of resistivity and Seebeck coefficient. Negative magnetoresistance（NMR） emerges with the appearance of localization effect and is gradually suppressed in high magnetic field. The temperature dependent phase coherence length extracted from the fittings of NMR also indicates the transition from WL to VRH. The measurement of Hall effect reveals an anomaly of temperature dependent carrier concentration caused by localization effect. Our findings show that RuAs2is a suitable platform to study the localized state.

关键词： RuAs2 single crystal variable range hopping weak localization

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Design and Implementation of Nonlinear Precoding for MIMO-SDMA Toward 6G Wireless

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China Communications 2024年第1期21卷 69-87页

作者： Chaowu Wu Yue Xiao Shu Fang Gang Wu national key laboratory of Wireless Communications University of Electronic Science and Technology of ChinaChengdu 611731China

In this paper,we present a novel and robust nonlinear precoding(NLP)design and detection structure specifically tailored for multiple-input multipleoutput space division multiple access(MIMO-SDMA)systems toward 6G wireless.Our approach aims to effectively mitigate the impact of imperfect channel estimation by leveraging the channel fluctuation mean square error(MSE)for reconstructing a highly accurate precoding matrix at the transmitter.Furthermore,we introduce a simplified receiver structure that eliminates the need for equalization,resulting in reduced interference and notable enhancements in overall system performance.We conduct both computer simulations and experimental tests to validate the efficacy of our proposed approach.The results reveals that the proposed NLP scheme offers significant performance improvements,making it particularly well-suited for the forthcoming 6G wireless.

关键词： MIMO-SDMA nonlinear precoding Tomlinson-Harashima precoding(THP) vector perturbation(VP)

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Arbitrary acoustic orbital angular momentum detection using dual-layer metasurfaces

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science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 106-112页

作者： Zhanlei Hao Haojie Chen Yuhang Yin Shan Zhu Yadong Xu Cheng-Wei Qiu Huanyang Chen Department of Physics College of Physical Science and TechnologyXiamen UniversityXiamen 361005China Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore Department of Mechanical and Electrical Engineering Xiamen UniversityXiamen 361005China Pen-Tung Sah Institute of micro-nano science and technology Xiamen UniversityXiamen 361005China School of Physical science and technology and Jiangsu key laboratory of Thin Films Soochow UniversitySuzhou 215006China

Orbital angular momentum(OAM),with its unique physical properties and vast application prospects,has attracted widespread attention in various fields.Nonetheless,the development of valid and practical acoustic OAM detection methods continues to be a challenging endeavor.In this paper,we propose a novel construction method of dual-layer metasurfaces to achieve a doubleconversion process for the waveform reshaping and differentiated focusing of two-dimensional vortex sources with different OAMs.Specifically,by utilizing a concise formula,a one-to-one correspondence is established between the OAM of incident vortex waves and different imaging points.The fundamental principle of this special conversion relationship is rigorously constrained by the directional compensation of phase and the material parameters of dual-layer metasurfaces with different quadratic phase distributions.More importantly,the highly consistent results between numerical demonstrations and acoustic experiments further confirm the feasibility and effectiveness of the proposed OAM detection scheme.Our work provides a new perspective on the precise manipulation for the phase of vortex fields,holding potential applications in super-resolution imaging and the design of acoustic OAM-based devices.

关键词： arbitrary acoustic OAM detection vortex waves dual-layer metasurfaces waveform reshaping differentiated focusing acoustic experiments

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Turbo Message Passing Based Burst Interference Cancellation for Data Detection in Massive MIMO-OFDM Systems

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China Communications 2024年第2期21卷 143-154页

作者： Wenjun Jiang Zhihao Ou Xiaojun Yuan Li Wang national key laboratory of Wireless Communications University of Electronic Science and Technology of ChinaChengdu 611731China

This paper investigates the fundamental data detection problem with burst interference in massive multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM) systems. In particular, burst interference may occur only on data symbols but not on pilot symbols, which means that interference information cannot be premeasured. To cancel the burst interference, we first revisit the uplink multi-user system and develop a matrixform system model, where the covariance pattern and the low-rank property of the interference matrix is discussed. Then, we propose a turbo message passing based burst interference cancellation(TMP-BIC) algorithm to solve the data detection problem, where the constellation information of target data is fully exploited to refine its estimate. Furthermore, in the TMP-BIC algorithm, we design one module to cope with the interference matrix by exploiting its lowrank property. Numerical results demonstrate that the proposed algorithm can effectively mitigate the adverse effects of burst interference and approach the interference-free bound.

关键词： burst interference cancellation data detection massive multiple-input multiple-output(MIMO) message passing orthogonal frequency division multiplexing(OFDM)

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Investigation of reflection anisotropy induced by micropipe defects on the surface of a 4H-SiC single crystal using scanning anisotropy microscopy

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Chinese Physics B 2024年第3期33卷 630-637页

作者：黄威俞金玲刘雨彭燕王利军梁平陈堂胜徐现刚刘峰奇陈涌海 key laboratory of Semiconductor Materials science Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials science and Opto-Electronic technology University of Chinese Academy of SciencesBeijing 100049China national key laboratory of Solid-state microwave Devices and Circuits Nanjing Electronic Devices InstituteNanjing 210016China Institute of micro/nano Devices and Solar Cells School of Physics and Information EngineeringFuzhou UniversityFuzhou 350108China State key laboratory of Crystal Materials Shandong UniversityJinan 250100China

Optical reflection anisotropy microscopy mappings of micropipe defects on the surface of a 4H-SiC single crystal are studied by the scanning anisotropy microscopy(SAM)system.The reflection anisotropy(RA)image with a'butterfly pattern'is obtained around the micropipes by SAM.The RA image of the edge dislocations is theoretically simulated based on dislocation theory and the photoelastic principle.By comparing with the Raman spectrum,it is verified that the micropipes consist of edge dislocations.The different patterns of the RA images are due to the different orientations of the Burgers vectors.Besides,the strain distribution of the micropipes is also deduced.One can identify the dislocation type,the direction of the Burgers vector and the optical anisotropy from the RA image by using SAM.Therefore,SAM is an ideal tool to measure the optical anisotropy induced by the strain field around a defect.

关键词： scanning anisotropy microscopy SiC reflection anisotropy edge dislocation

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Bioinspired sensing-memory-computing integrated vision systems: biomimetic mechanisms, design principles, and applications

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science China(Information sciences) 2024年第5期67卷 5-27页

作者： Yujie HUANG Yinlong TAN Yan KANG Yabo CHEN Yuhua TANG Tian JIANG Institute for Quantum Information and State key laboratory of High Performance Computing College of Computer National University of Defense Technology College of Advanced Interdisciplinary Studies National University of Defense Technology Institute for Quantum science and technology College of ScienceNational University of Defense Technology

With the explosion of sensory data in the Internet of Things(Io T) era, conventional machine vision systems are becoming increasingly difficult to meet the requirements of high efficiency, low energy consumption, and low latency due to their inherent shortcomings of separate sensing, memory, and computing units. Inspired by the retina and neuromorphic computing, the sensing-memory-computing integrated vision system(SMCVS) that features low power consumption, low latency, and high parallelism has been considered a promising technology to surpass the von Neumann architecture and realize strong artificial intelligence.Meanwhile, novel materials like two-dimensional semiconductors and quantum dots with novel optoelectronic performance provide hardware carriers for implementing integrated sensing-memory-computing architectures,attracting considerable attention. This paper reviews the recent research progress in bioinspired vision systems in terms of biomimetic mechanisms, design principles, computational architectures, and applications.Firstly, the biomimetic mechanisms are illustrated to guide the design of high-performance artificial visual perception systems. Then the research progress of optoelectronic-synapse-based bioinspired vision systems in the device principles and applications including image filtering, color recognition, visual adaptation, and motion detection are summarized. Finally, the challenges and future developing directions of the SMCVS are provided regarding bionic application, architecture design, and device fabrication.

关键词： sensing-memory-computing architecture neuromorphic computing retinomorphic device image recognition visual system

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All laser direct writing process for temperature sensor based on graphene and silver

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Frontiers of Optoelectronics 2024年第1期17卷 45-55页

作者： Qi Li Ruijie Bai Lianbo Guo Yang Gao Shanghai key laboratory of Intelligent Sensing and Detection technology School of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237China North Automatic Control technology Institute Taiyuan 030006China Wuhan national laboratory for Optoelectronics Huazhong University of Science&TechnologyWuhan 430074China

A highly sensitive temperature sensing array is prepared by all laser direct writing(LDW)method,using laser induced silver(LIS)as electrodes and laser induced graphene(LIG)as temperature sensing layer.A finite element analysis(FEA)photothermal model incorporating a phase transition mechanism is developed to investigate the relationship between laser parameters and LIG properties,providing guidance for laser processing parameters selection with laser power of 1–5 W and laser scanning speed(greater than 50 mm/s).The deviation of simulation and experimental data for widths and thickness of LIG are less than 5%and 9%,respectively.The electrical properties and temperature responsiveness of LIG are also studied.By changing the laser process parameters,the thickness of the LIG ablation grooves can be in the range of 30–120μm and the resistivity of LIG can be regulated within the range of 0.031–67.2Ω・m.The percentage temperature coefficient of resistance(TCR)is calculated as−0.58%/°C.Furthermore,the FEA photothermal model is studied through experiments and simulations data regarding LIS,and the average deviation between experiment and simulation is less than 5%.The LIS sensing samples have a thickness of about 14μm,an electrical resistivity of 0.0001–100Ω・m is insensitive to temperature and pressure stimuli.Moreover,for a LIS-LIG based temperature sensing array,a correction factor is introduced to compensate for the LIG temperature sensing being disturbed by pressure stimuli,the temperature measurement difference is decreased from 11.2 to 2.6°C,indicating good accuracy for temperature measurement.

关键词： Laser direct writing Temperature sensor Finite element analysis Laser induced graphene Laser induced silver

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Dynamic response of a thermal transistor to time-varying signals

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Chinese Physics B 2024年第5期33卷 13-19页

作者：阮琴丽刘文君王雷 Department of Physics Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devicesand Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education)Renmin University of ChinaBeijing 100872China

Thermal transistor,the thermal analog of an electronic transistor,is one of the most important thermal devices for microscopic-scale heat manipulating.It is a three-terminal device,and the heat current flowing through two terminals can be largely controlled by the temperature of the third one.Dynamic response plays an important role in the application of electric devices and also thermal devices,which represents the devices’ability to treat fast varying inputs.In this paper,we systematically study two typical dynamic responses of a thermal transistor,i.e.,the response to a step-function input(a switching process)and the response to a square-wave input.The role of the length L of the control segment is carefully studied.It is revealed that when L is increased,the performance of the thermal transistor worsens badly.Both the relaxation time for the former process and the cutoff frequency for the latter one follow the power-law dependence on L quite well,which agrees with our analytical expectation.However,the detailed power exponents deviate from the expected values noticeably.This implies the violation of the conventional assumptions that we adopt.

关键词： phonon phononics thermal transistor dynamic response heat conduction

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