Wang Hengshan, Yin Yanfeng, Xu Jiao, Li Jing, Bao Yanan, An Meiqi, Tang Lingzhi, Jin Shengye, Tian Wenming, Yang Yiming
School of Integrated Circuits, Dalian University of Technology, No. 321 Tuqiang Road, Dalian 116620, China.
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
ACS Nano. 2023 Dec 12;17(23):23671-23678. doi: 10.1021/acsnano.3c06944. Epub 2023 Nov 17.
The dynamic crystal lattice of halide perovskites facilitates the coupled transport of ions and electrons, offering innovative concepts in semiconductor iontronic devices that surpass solar cell applications. However, a comprehensive understanding of the intricacies of coupled ionic and electronic transport at the microscale remains ambiguous, owing to the inhomogeneity in ploy-crystalline perovskite thin films. In this work, we employed one-dimensional (1D) single-crystalline CsPbBr nanowires (NWs) to investigate the electric field induced ionic transport. Upon poling by an external bias, the previously uniform NW exhibits highly anisotropic ionic transport, which is identified as the origin of the giant switchable photovoltaic effect by spatially resolved scanning photocurrent microscopy. The subsequent ultrafast scanning photoluminescence (PL) microscopy measurements demonstrate significant localization of photocarriers near one terminal of the device, which is attributed to the accumulation of halogen vacancies. In addition, thanks to the enhancement of the local electric field, the poled device shows a 10-fold increase of photoresponse speed. Our findings favor the scale-down of perovskite devices to the submicrometer scale, extending their applications in self-powered iontronic and optoelectronic devices.
卤化物钙钛矿的动态晶格促进了离子和电子的耦合传输，为超越太阳能电池应用的半导体离子电子器件提供了创新概念。然而，由于多晶钙钛矿薄膜的不均匀性，对微观尺度上离子和电子耦合传输的复杂性仍缺乏全面理解。在这项工作中，我们使用一维（1D）单晶CsPbBr纳米线（NWs）来研究电场诱导的离子传输。在外部偏压极化后，先前均匀的NW表现出高度各向异性的离子传输，通过空间分辨扫描光电流显微镜确定这是巨大可切换光伏效应的起源。随后的超快扫描光致发光（PL）显微镜测量表明，光载流子在器件的一个终端附近显著局域化，这归因于卤素空位的积累。此外，由于局部电场的增强，极化后的器件光响应速度提高了10倍。我们的研究结果有利于将钙钛矿器件缩小到亚微米尺度，扩展其在自供电离子电子和光电器件中的应用。
