Piezo-Phototronic Effect-Induced Self-Powered Broadband Photodetectors using Environmentally Stable α-CsPbI3 Perovskite Nanocrystals

Utilizing the remarkably high light absorption and long carrier diffusion length of inorganic perovskites, superior performance self-powered broadband photodetectors using the vertical heterojunction of cesium lead iodide (CsPbI3) nanocrystals (NCs) and zinc oxide (ZnO) films on a flexible platform are reported. Here, the pure cubic or alpha-phase of as-synthesized CsPbI3 NCs facilitate the novelty of the present work in terms of their enhanced structural stability suitable for optical applications. The alpha-CsPbI3/ZnO device exhibits superior performance with photoresponsivity of approximate to 8.2 AW(-1), ON/OFF ratio of approximate to 2.4 x 10(4), and specific detectivity up to approximate to 1.4 x 10(12) Jones. Furthermore, the piezo-phototronic effect of ZnO has been exploited to enhance the device performance by utilizing the compressive strain-induced piezoelectric charges for modulating the generation, separation, and transportation of charge carriers. By introducing an approximate -0.042% compressive strain in the hybrid heterostructure, the enhancement of photocurrent, spectral responsivity, and specific detectivity of the detector by approximate to 619%, approximate to 536%, and approximate to 506%, respectively, under visible light illumination has been successfully achieved. This work not only presents an inventive method for improving the performance of perovskite photodetectors through interface engineering, but it also provides a thorough understanding of the piezo-phototronic effect on optoelectronic devices.