检索结果-南通市图书馆

Hot-exciton effects on exciton diffusion and circular polarization dynamics in a single PbI_(2)nanoflake

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第1期67卷 83-90页

作者： XU ChenYu WANG Lei CUI Lin GAO BingRong WANG HaiYu state key laboratory of integrated optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

As one of the emerging two-dimensional lead halide materials,lead iodide(PbI_(2))nanosheets have proven to possess strong application potential in the fields of high-energy radiation detection and highly efficient perovskite solar ***,the underlying photophysical properties such as hot-exciton-related carrier dynamics remain unclear for PbI_(2)***,we report the exciton dynamics of a single PbI_(2)nanoflake prepared by an aqueous solution *** a three-dimensional(3D)diffusion model,we obtain the exciton annihilation radius and diffusion coefficient of a single PbI_(2)nanoflake under nonresonant and resonant excitation conditions of band-edge exciton *** initial exciton densities increase,we find the carrier recombination mechanism for a single PbI_(2)nanoflake gradually changes from exciton-exciton annihilation to free-carrier ***,we reveal the room-temperature circular polarization of a single PbI_(2)nanoflake is due to free-carrier recombination with a band-edge exciton dissociation time of~120 fs under the resonant excitation condition.

关键词： single PbI_(2)nanoflake exciton diffusion room-temperature circular polarization ultrafast spectroscopy

Transient features of graphitization and nitrogen-vacancy color centers in a diamond fabricated by localization femtosecond laser direct writing

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第8期67卷 2530-2536页

作者： CUI Lin YIN SiYu HU ZiFan WANG Lei state key laboratory of integrated optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

Femtosecond laser direct writing provides an efficient approach to fabricating single nitrogen vacancy(NV) color centers with a relatively high yield. Different from previously reported NV color centers with a random distribution in a bulk diamond or nanocrystals, this gives an opportunity to study the photophysical properties of single NV color centers with precise numbers and positions. However, ultrafast studies on single NV color centers prepared by localization femtosecond laser direct writing are still rare, especially for the graphitization inside a diamond and its relationship with single NV color centers. Here, we report the broadband transient absorption(TA) spectroscopic features of the graphitization and NV color centers in a diamond fabricated by localization femtosecond laser direct writing at room temperature under 400 nm excitation. In comparison with the graphene oxide film, the bleaching features of the graphitization point array in a diamond are similar to reduced graphene oxide,accompanied by excited state absorption signals from local carbon atom vacancy defects in graphene-like structures induced by laser writing. On the other hand, transient features of laser processing array containing single NV color centers with a yield of~50% are different from those of the graphitization point array. Our findings suggest that for ultrashort pulse processing of diamonds, broadband TA spectral signals are sensitive to the surrounding atomic environment of processing sites, which could be applied to laser writing point defects in other materials used as solid-state single photon sources.

关键词： nitrogen-vacancy color center graphitization diamond femtosecond laser direct writing ultrafast spectroscopy

Effect of annealing on the electrical performance of N-polarity GaN Schottky barrier diodes

在线全文

学校读者我要写书评

暂无评论

Journal of Semiconductors 2024年第4期45卷 48-55页

作者： Nuo Xu Gaoqiang Deng Haotian Ma Shixu Yang Yunfei Niu Jiaqi Yu Yusen Wang Jingkai Zhao Yuantao Zhang state key laboratory of integrated optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

A nitrogen-polarity(N-polarity)GaN-based high electron mobility transistor(HEMT)shows great potential for high-fre-quency solid-state power amplifier applications because its two-dimensional electron gas(2DEG)density and mobility are mini-mally affected by device ***,the Schottky barrier height(SBH)of N-polarity GaN is *** leads to a large gate leakage in N-polarity GaN-based *** this work,we investigate the effect of annealing on the electrical characteristics of N-polarity GaN-based Schottky barrier diodes(SBDs)with Ni/Au *** results show that the annealing time and tem-perature have a large influence on the electrical properties of N-polarity GaN *** to the N-polarity SBD without annealing,the SBH and rectification ratio at±5 V of the SBD are increased from 0.51 eV and 30 to 0.77 eV and 7700,respec-tively,and the ideal factor of the SBD is decreased from 1.66 to 1.54 after an optimized annealing *** analysis results suggest that the improvement of the electrical properties of SBDs after annealing is mainly due to the reduction of the inter-face state density between Schottky contact metals and N-polarity GaN and the increase of barrier height for the electron emis-sion from the trap state at low reverse bias.

关键词： nitrogen polarity GaN Schottky barrier diodes annealing interface state

Spatial light modulation for femtosecond laser manufacturing:Current developments and challenges

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第1期67卷 60-72页

作者： ZANG Xue LIU ZiTing XU YiShi WANG Yi WANG Qing LI ZhenZe WANG Lei state key laboratory of integrated optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China state key laboratory of Precision Measurement and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China

Since the invention of lasers,spatial-light-modulated laser processing has become a powerful tool for various *** enables multidimensional and dynamic modulation of the laser beam,which significantly improves the processing efficiency,accuracy,and flexibility,and presents wider prospects over traditional mechanical technologies for machining three-dimensional,hard,brittle,or transparent *** this review,we introduce:(1)The role of spatial light modulation technology in the development of femtosecond laser manufacturing;(2)the structured light generated by spatial light modulation and its generation methods;and(3)representative applications of spatial-light-modulated femtosecond laser manufacturing,including aberration correction,parallel processing,focal field engineering,and polarization ***,we summarize the present challenges in the field and possible future research.

关键词： femtosecond laser manufacturing spatial light modulation structured light aberration correction parallel processing focal field engineering polarization control

Laser manufacturing of spatial resolution approaching quantum limit

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2024年第3期13卷 421-428页

作者： Xiao-Jie Wang Hong-Hua Fang Zhen-Ze Li Dan Wang Hong-Bo Sun state key laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China state key laboratory of integrated optoelectronics College of Electronic Science and EngineeringJilin University2699 Qianjin StreetChangchun 130012China

Atomic and close-to-atom scale manufacturing is a promising avenue toward single-photon emitters,single-electron transistors,single-atom memory,and quantum-bit devices for future communication,computation,and sensing *** manufacturing is outstanding to this end for ease of beam manipulation,batch production,and no requirement for *** is,however,suffering from optical diffraction ***,we report a spatial resolution improved to the quantum limit by exploiting a threshold tracing and lock-in method,whereby the two-order gap between atomic point defect complexes and optical diffraction limit is surpassed,and a feature size ofintegrated quantum technological applications.

关键词： quantum limit resolution

Multifunctional interfacial molecular bridge enabled by an aggregation-induced emission strategy for enhancing efficiency and UV stability of perovskite solar cells

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第8期95卷 588-595,I0013页

作者： Shuhang Bian Yuqi Wang Fancong Zeng Zhongqi Liu Bin Liu Yanjie Wu Long Shao Yongzhi Shao Huan Zhang Shuainan Liu Jin Liang Xue Bai Lin Xu Donglei Zhou Biao Dong Hongwei Song state key laboratory on integrated optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012JilinChina College of Science Shanghai UniversityShanghai 200444China

The interface defects between the electron transport layer(ETL)and the perovskite layer,as well as the low ultraviolet(UV)light utilization rate of the perovskite absorption layer,pose significant challenges for the commercialization of perovskite solar cells(PSCs).To address this issue,this paper proposes an innovative multifunctional interface modulation strategy by introducing aggregation-induced emission(AIE)molecule 5-[4-[1,2,2-tri[4-(3,5-dicarboxyphenyl)phenyl]ethylene]phenyl]benzene-1,3-dicarboxylic acid(H_(8)ETTB)at the SnO_(2)ETL/perovskite ***,the interaction of H_(8)ETTB with the SnO_(2)surface,facilitated by its carboxyl groups,is effective in passivating surface defects caused by noncoord inated Sn and O *** interaction enhances the conductivity of the SnO_(2)film and adjusts energy levels,leading to enhanced charge carrier ***,H_(8)ETTB can passivate noncoord inated Pb^(2+)ions at the perovskite interface,promoting perovskite crystallization and reducing the interface energy barrier,resulting in a perovskite film with low defects and high crystalline *** importantly,the H_(8)ETTB molecule,can convert UV light into light absorbable by the perovskite,thereby reducing damage caused by UV light and improving the device's utilization of ***,the champion PSC based on SnO_(2)-H_(8)ETTB achieves an impressing efficiency of 23.32%and significantly improved photostability compared with the control device after continuous exposure to intense UV *** addition,the Cs_(0.05)(FA_(0.95)MA_(0.05))_(0.95)Pb(I_(0.95)Br_(0.05))_(3)based device can achieve maximum efficiency of 24.01%,demonstrating the effectiveness and universality of this ***,this innovative interface bridging strategy effectively tackles interface defects and low UV light utilization in PSCs,presenting a promising approach for achieving highly efficient and stable PSCs.

关键词： Perovskite solar cells Aggregation-induced emission Defect passivation Efficiency UV stability

Doping suppresses lattice distortion of vacant quadruple perovskites to activate self-trapped excitons emission

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第4期17卷 3068-3078页

作者： Zhipeng Chen Fei Zhang Dongwen Yang Huifang Ji Xu Chen Di Wu Xinjian Li Yu Zhang Zhifeng Shi key laboratory of Materials Physics of Ministry of Education School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China state key laboratory on integrated optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

The vacancy-ordered quadruple perovskite Cs_(4)CdBi_(2)Cl_(12),as a newly-emerging lead-free perovskite system,has attracted great research interest due to its excellent stability and direct band ***,the poor luminescence performance limits its application in light-emitting diodes(LEDs)and other ***,for the first time,an Ag^(+)ion doping strategy was proposed to greatly improve the emission performance of Cs_(4)CdBi_(2)Cl_(12) synthesized by hydrothermal *** functional theory calculations combined with experimental results evidence that the weak orange emission from Cs_(4)CdBi_(2)Cl_(12) is attributed to the phonon scattering and energy level crossing due to the large lattice distortion under excited ***,Ag^(+)ion doping breaks the intrinsic crystal field environment of Cs_(4)CdBi_(2)Cl_(12),suppresses the crossover between ground and excited states,and reduces the energy loss in the form of nonradiative *** a critical doping amount of 0.8%,the emission intensity of Cs_(4)CdBi_(2)Cl_(12):Ag^(+)reaches the maximum,about eight times that of the pristine ***,the doped Cs_(4)CdBi_(2)Cl_(12) still maintains excellent stability against heat,ultraviolet irradiation,and environmental oxygen/*** above advantages make it possible for this material to be used as solid-state phosphors for white LEDs applications,and the Commission International de I’Eclairage color coordinates of(0.31,0.34)and high color rendering index of 90.6 were *** importantly,the white LED demonstrates remarkable operation stability in air ambient,showing almost no emission decay after a long working time for 48 *** believe that this study puts forward an effective ion-doping strategy for emission enhancement of vacancy-ordered quadruple perovskite Cs_(4)CdBi_(2)Cl_(12),highlighting its great potential as efficient emitter compatible for practical applications.

关键词： Cs_(4)CdBi_(2)Cl_(12) self-trapped excitons ion doping emission enhancement stability

Moiré superlattices arising from growth induced by screw dislocations in layered materials

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第7期33卷 72-77页

作者：田伏钰 Muhammad Faizan 贺欣孙远慧张立军 state key laboratory of integrated optoelectronics key laboratory of Automobile Materials of MOE and College of Materials Science and engineering Jilin UniversityChangchun 130012China Suzhou laboratory Suzhou 215123China

Moiré superlattices(MSLs) are modulated structures produced from homogeneous or heterogeneous two-dimensional layers stacked with a twist angle and/or lattice mismatch. Enriching the methods for fabricating MSL and realizing the unique emergent properties are key challenges in its investigation. Here we recommend that the spiral dislocation driven growth is another optional method for the preparation of high quality MSL samples. The spiral structure stabilizes the constant out-of-plane lattice distance, causing the variations in electronic and optical properties. Taking SnS_(2) MSL as an example, we find prominent properties including large band gap reduction(~ 0.4 e V) and enhanced optical activity. Firstprinciples calculations reveal that these unusual properties can be ascribed to the locally enhanced interlayer interaction associated with the Moiré potential modulation. We believe that the spiral dislocation driven growth would be a powerful method to expand the MSL family and broaden their scope of application.

关键词： Moirésuperlattices interlayer interaction spiral dislocation layered materials

electronic structure tuning of layered double hydroxides for electrochemical sensing and its biomedical applications

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第11期67卷 3614-3630页

作者： Kun Wang Zhiying Cao Qihang Ding Jiyoung Yoo Nem Singh Heemin Kang Lin Wang Lin Xu Jong Seung Kim School and Hospital of Stomatology Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling Jilin University state key laboratory on integrated optoelectronics Collage of Electronic Science and Engineering Jilin University department of Chemistry Korea University department of Materials Science and engineering Korea University

Modifying the electrodes of electrochemical sensors is critical to enhance sensitivity, selectivity, and stability, ultimately improving both their effectiveness and performance. In this paper, recent advancements in electrochemical sensors are reviewed,focusing on the utilization of layered double hydroxides(LDHs). The first section explores the advantageous and disadvantageous aspects of electrochemical sensing. Benefits include rapid response, ease of operation, and cost-effectiveness,while drawbacks concern the potential instability of prolonged use, susceptibility to interference, and the risk of biomolecule inactivation. Following this, the second section delves into the synthesis, constituents, and structure of LDHs. Moreover, after introducing the chemical mechanisms and functions of LDHs in electrochemical sensors, we concentrate on diverse modifying materials of LDHs and their different performances. Finally, the applications of LDHs in electrochemical sensing across different fields are discussed. This review aims to facilitate the continued advancement for applying LDHs in electrochemical sensors, as well as inspire the evolution of electrochemical sensing technology.

关键词： layered double hydroxides electrochemical sensor biological field modified electrode