卤化物钙钛矿纳米材料中离子动力学的扫描探针显微镜研究

In recent years, halide perovskite solar cells attract extensive attention due to their high efficiency and low cost. However, this class of materials suffers from several issues including I-V hysteresis, light induced phase separation, and ambiguous origin of excellent photovoltaic performance, hindering the practical application of perovskite solar cells. Many of these issues are related to the dynamic behaviors of ion in the material, such as ion diffusion, migration, and spatial reconfiguration. Therefore, in this proposal, we select low-dimensional halide perovskite nanocrystals as the target system, and investigate ion dynamics in the material including halide ion transport dynamics, polarization due to reconfiguration of organic groups, transport of external injected ions, as well as their impact on the electronic, optoelectronic, and photovoltaic properties. By fabricating micro- and nanoscale devices, the ion distribution, local optoelectronic and polarization information can be obtained by spatially resolved scanning probe microcopye techniques, such as the scanning laser photocurrent microscope and resonance-enhanced piezoresponse force microscope. This research aims to establish ion dynamics model for halide perovskite, which lays basis for solving the critical questions in perovskite solar cells. In addition, we will also exploit the potential application of ion behaviors in resistive switch random access memories, optoelectronics, battery electrodes, and ferroelectrics.

近年来，基于卤化物钙钛矿材料的太阳能电池以其“高效率+低价格”的优势引起了极大关注。然而，材料中存在的I-V回滞、光致相分离、优良光伏特性来源不明确等问题，对钙钛矿太阳能电池的产业化提出了挑战。这些问题都与材料中离子的扩散，定向迁移，空间位形重构等动力学性质相关。因此，本项目以低维卤化物钙钛矿纳米单晶作为研究体系，着重研究材料中的离子动力学，包括卤素离子的输运动力学、有机基团重构引起的极化、外部引入离子在材料中的输运、以及上述离子行为对材料电学、光电与光伏特性的影响。通过制备基于纳米材料的微纳器件，并应用具有空间分辨率的扫描探针技术（如扫描激光-光电流显微镜与共振压电响应力显微镜等）对材料中的离子分布、局域光电与极化性质等进行测量。研究将建立材料中的离子动力学模型，为解决钙钛矿太阳能电池中的关键问题打下研究基础，并探索离子行为在阻变存储器、光电传感器、电极材料、铁电器件等方向的应用。

近年来，基于卤化物钙钛矿材料的太阳能电池以其“高效率+低价格”的优势引起了极大关注。然而，材料中存在的I-V回滞、光致相分离、优良光伏特性来源不明确等问题，对钙钛矿太阳能电池的产业化提出了挑战。这些问题都与材料中离子的扩散，定向迁移，空间位形重构等动力学性质相关。因此，本项目以低维卤化物钙钛矿纳米单晶作为研究体系，着重研究材料中的离子动力学，包括卤素离子的输运动力学以及上述离子行为对材料电学、光电与光伏特性的影响。通过制备基于纳米材料的微纳器件，并应用具有空间分辨率的扫描探针技术（如扫描激光-光电流显微镜）对材料中的离子分布与局域光电性质等进行测量。研究建立了材料中的离子动力学模型，为解决钙钛矿太阳能电池中的关键问题打下研究基础。特别地，在一维纳米线中发现的由阈值驱动的离子扩散行为可用以制备高耐热性钙钛矿异质结，为其在太阳能电池、LED等光电器件中的应用提供了理论基础。