Hong Zhen, Quan Hongying, Ke Changying, Ouyang Zhiyong, Cheng Baochang
School of Materials Science and Engineering, Nanchang Hangkong University, Jiangxi 330063, P. R. China.
School of Environment and Energy, Jiangxi Modern Polytechnic College, Jiang Xi 330095, P. R. China.
Nanoscale. 2023 Aug 17;15(32):13359-13370. doi: 10.1039/d3nr01921g.
Nanostructured hybrid organic-inorganic perovskites exhibit remarkable photodetection performance due to their abundant surface states and high responsivity to visible light. However, in traditional photodetectors with a symmetrical configuration of two-terminal electrodes, the photoresponse is independent of bias polarity. Moreover, for self-powered photodetectors, an asymmetric structure of the chemical composition, such as p-n and Schottky junctions, and two different electrodes are necessary. Herein, we demonstrate a modulable asymmetrical photoresponse by packing only one electrode end in a single CHNHPbI micro/nanowire with two symmetrical Ag electrodes. This not only enables the high performance of light- and bias-modulated multifunctional photorectifiers and self-powered photodetectors, but also allows controllable implementation of nonvolatile photomemory with a tunable spectral responsivity and range. At an unpacked electrode interface, trace moisture in the environment promotes a good bonding of Ag and I, substantially decreasing the interface barrier. Conversely, at a packed electrode interface, abundant surface states can be well preserved, leading to a high interface barrier. Notably, under a large voltage and strong light, the redox of Ag/AgI at the unpacked electrode interface and the injection and ejection of holes at the packed electrode interface can be reversibly conducted by inverting the voltage polarity, enabling a controllable nonvolatile modulation. Therefore, by clarifying the actual origin of the photoelectrical response of CHNHPbI micro/nanowires at electrode interfaces, high-performance multifunctional photorectifiers and self-powered photodetectors based on asymmetrical interface photovoltaic effects with two symmetrical electrodes can be controllably realized. Furthermore, by precise cooperative modulation of two electrode interface states with a large voltage and strong illumination, nonvolatile photomemory with a tunable spectral responsivity and range can be implemented.
纳米结构的有机-无机杂化钙钛矿由于其丰富的表面态和对可见光的高响应性而表现出卓越的光电探测性能。然而，在具有两端电极对称配置的传统光电探测器中，光响应与偏置极性无关。此外，对于自供电光电探测器，需要化学成分的不对称结构，如p-n结和肖特基结，以及两个不同的电极。在此，我们通过在单个CHNHPbI微/纳米线中仅将一个电极端与两个对称的Ag电极封装在一起，展示了一种可调制的不对称光响应。这不仅实现了光调制和偏置调制的多功能光整流器和自供电光电探测器的高性能，还允许可控地实现具有可调光谱响应度和范围的非易失性光存储器。在未封装的电极界面处，环境中的微量水分促进了Ag和I的良好结合，大幅降低了界面势垒。相反，在封装的电极界面处，丰富的表面态可以得到很好的保留，导致高界面势垒。值得注意的是，在大电压和强光下，通过反转电压极性，可以在未封装的电极界面处可逆地进行Ag/AgI的氧化还原以及在封装的电极界面处进行空穴的注入和抽出，从而实现可控的非易失性调制。因此，通过阐明CHNHPbI微/纳米线在电极界面处光电响应的实际起源，可以可控地实现基于具有两个对称电极的不对称界面光伏效应的高性能多功能光整流器和自供电光电探测器。此外，通过用大电压和强光精确协同调制两个电极界面状态，可以实现具有可调光谱响应度和范围的非易失性光存储器。
