Lan Chuntao, Zou Haiyang, Wang Longfei, Zhang Meng, Pan Shuang, Ma Ying, Qiu Yiping, Wang Zhong Lin, Lin Zhiqun
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
Key Laboratory of Textile Science & Technology of Ministry of Education, College of Textiles, Donghua University, Shanghai, 201620, China.
Adv Mater. 2020 Nov;32(47):e2005481. doi: 10.1002/adma.202005481. Epub 2020 Oct 21.
Despite recent rapid advances in metal halide perovskites for use in optoelectronics, the fundamental understanding of the electrical-poling-induced ion migration, accounting for many unusual attributes and thus performance in perovskite-based devices, remain comparatively elusive. Herein, the electrical-poling-promoted polarization potential is reported for rendering hybrid organic-inorganic perovskite photodetectors with high photocurrent and fast response time, displaying a tenfold enhancement in the photocurrent and a twofold decrease in the response time after an external electric field poling. First, a robust meniscus-assisted solution-printing strategy is employed to facilitate the oriented perovskite crystals over a large area. Subsequently, the electrical poling invokes the ion migration within perovskite crystals, thus inducing a polarization potential, as substantiated by the surface potential change assessed by Kelvin probe force microscopy. Such electrical-poling-induced polarization potential is responsible for the markedly enhanced photocurrent and largely shortened response time. This work presents new insights into the electrical-poling-triggered ion migration and, in turn, polarization potential as well as into the implication of the latter for optoelectronic devices with greater performance. As such, the utilization of ion-migration-produced polarization potential may represent an important endeavor toward a wide range of high-performance perovskite-based photodetectors, solar cells, transistors, scintillators, etc.
尽管近年来用于光电子学的金属卤化物钙钛矿取得了快速进展，但对于电极化诱导的离子迁移的基本理解仍然相对难以捉摸，而这种迁移解释了许多异常特性以及基于钙钛矿的器件的性能。在此，报道了通过电极化提升的极化电势，用于制造具有高光电流和快速响应时间的有机-无机杂化钙钛矿光电探测器，在外部电场极化后，光电流增强了十倍，响应时间缩短了一半。首先，采用一种强大的弯月面辅助溶液印刷策略，以促进大面积上钙钛矿晶体的取向。随后，电极化引发钙钛矿晶体内的离子迁移，从而诱导出极化电势，这通过开尔文探针力显微镜评估的表面电势变化得到证实。这种电极化诱导的极化电势是光电流显著增强和响应时间大幅缩短的原因。这项工作为电极化引发的离子迁移以及由此产生的极化电势提供了新的见解，以及后者对高性能光电器件的意义。因此，利用离子迁移产生的极化电势可能是朝着广泛的高性能钙钛矿基光电探测器、太阳能电池、晶体管、闪烁体等迈出的重要一步。
