Tong Guoqing, Jiang Maowei, Son Dae-Yong, Qiu Longbin, Liu Zonghao, Ono Luis K, Qi Yabing
Energy Materials and Surface Sciences Unit (EMSSU), Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan.
ACS Appl Mater Interfaces. 2020 Mar 25;12(12):14185-14194. doi: 10.1021/acsami.0c01056. Epub 2020 Mar 16.
Control of forward and inverse reactions between perovskites and precursor materials is key to attaining high-quality perovskite materials. Many techniques focus on synthesizing nanostructured CsPbX materials (e.g., nanowires) via a forward reaction (CsX + PbX → CsPbX). However, low solubility of inorganic perovskites and complex phase transition make it difficult to realize the precise control of composition and length of nanowires using the conventional forward approach. Herein, we report the self-assembly inverse growth of CsPbBr micronanowires (MWs) (CsPbBr → CsPbBr + PbBr↑) by controlling phase transition from CsPbBr to CsPbBr. The two-dimensional (2D) structure of CsPbBr serves as nucleation sites to induce initial CsPbBr MW growth. Also, phase transition allows crystal rearrangement and slows down crystal growth, which facilitates the MW growth of CsPbBr crystals along the 2D planes of CsPbBr. A CsPbBr MW photodetector constructed based on the inverse growth shows a high responsivity of 6.44 A W and detectivity of ∼10 Jones. Large grain size, high crystallinity, and large thickness can effectively alleviate decomposition/degradation of perovskites, which leads to storage stability for over 60 days in humid environment (relative humidity = 45%) and operational stability for over 3000 min under illumination (wavelength = 400 nm, light intensity = 20.06 mW cm).
钙钛矿与前驱体材料之间正向和逆向反应的控制是获得高质量钙钛矿材料的关键。许多技术专注于通过正向反应（CsX + PbX → CsPbX）合成纳米结构的CsPbX材料（例如纳米线）。然而，无机钙钛矿的低溶解度和复杂的相变使得使用传统的正向方法难以实现对纳米线组成和长度的精确控制。在此，我们报道了通过控制从CsPbBr到CsPbBr的相变，CsPbBr微米纳米线（MWs）的自组装逆向生长（CsPbBr → CsPbBr + PbBr↑）。CsPbBr的二维（2D）结构作为成核位点诱导初始CsPbBr MW生长。此外，相变允许晶体重排并减缓晶体生长，这有利于CsPbBr晶体沿着CsPbBr的2D平面进行MW生长。基于逆向生长构建的CsPbBr MW光电探测器显示出6.44 A W的高响应度和约10 Jones的探测率。大晶粒尺寸、高结晶度和大厚度可以有效减轻钙钛矿的分解/降解，这导致在潮湿环境（相对湿度 = 45%）中储存稳定性超过60天，在光照下（波长 = 400 nm，光强度 = 20.06 mW cm）运行稳定性超过3000分钟。
