Flexible CsPbBr3 microwire photodetector with a performance enhanced by covering it with an Ag nanolayer

Abstract

Owing to their large absorption coefficient, high carrier mobility, long diffusion length, low defect density and tunable direct band gap, low-dimensional perovskite structures have been widely regarded as promising candidates for developing next-generation photo-electrical devices. Herein, we proposed and presented a high-performance photoconductive detector, which is composed of a single CsPbBr₃ microwire covered by a Ag nanolayer (Ag@CsPbBr₃). The Ag@CsPbBr₃ microwire detector reveals a higher responsivity of 18.96 A W⁻¹, a linear detection range (LDR) of 84.72 dB, a detectivity of 1.67 × 10¹⁴ Jones, and an external quantum efficiency (EQE) of 5.60 × 10³% upon the operation of 405 nm light illumination at an operating bias of 3 V. The on–off switching ratio of the Ag@CsPbBr₃ detector reached up to 10⁵, a higher photoresponse speed with a rising/falling time of 17/57 ms, and excellent stability to ultraviolet-visible light signals. The performance of the device has been greatly enhanced. The performance-increased photodetecting mechanism was exploited. That is, cladding a Ag nanolayer can not only achieve surface cleaning modulation to inhibit perovskite degradation but also facilitate the separation of photogenerated charge carriers in the CsPbBr₃ MW, thus enabling fast charge transfer. In particular, the influence of the Ag nanofilm on the long-term stability of the fabricated CsPbBr₃ microwire detector is considerably positive. The experimental research provides an innovative scheme for manufacturing photosensitive, stable, and flexible perovskite photodetection devices and will promote their commercial applications in the future.