Plasmon-enhanced photoresponse and stability of a CsPbBr3 microwire/GaN heterojunction photodetector with surface-modified Ag nanoparticles

Abstract

Possessing the superior properties of high optical absorption coefficient, high mobility, long carrier diffusion length and low defect density, the family of one-dimensional perovskite monocrystals has been extensively used to construct optoelectronic devices. Herein, we proposed and reported a one-dimensional perovskite broadband light-sensing device, which was composed of a CsPbBr₃ microwire covered by Ag nanoparticles (AgNPs@CsPbBr₃ MW) and a p-GaN heterojunction. The AgNPs@CsPbBr₃/GaN heterojunction device exhibited broadband detection capabilities ranging from the near ultraviolet to visible region. The device revealed a highest responsivity of 63.9 A W⁻¹, a maximum value of detectivity of ∼4.05 × 10¹² Jones, fast photoresponse speed (rising/decaying time ∼1.0 ms/21.3 ms), and high external quantum efficiency of 1.5 × 10⁴% at −8.0 V under 530 nm light illumination via 1.20 mW cm⁻². The photoresponse performances largely surpassed those of previously published CsPbBr₃-related low-dimensional heterojunction photodetectors. Systematic investigations illustrated that the performance enhancement was derived from the surface-modified AgNPs, which enables the optimization of the CsPbBr₃ properties, such as contributing passivation of surface defects, enhancing light absorption, boosting photosensitivity, accelerating electronic transport and so on. In particular, the long-term stability of the optimized AgNPs@CsPbBr₃/GaN heterojunction photodetector was considerably enhanced. This study supplies a workable strategy to construct high-performance perovskite optoelectronic devices with excellent sensitivity and stability, and further may facilitate their realistic application in future.