Plasmonic and Graphene-Functionalized High-Performance Broadband Quasi-Two-Dimensional Perovskite Hybrid...

Quasi-two-dimensional (2D) layered organic-inorganic hybrid perovskites have attracted extensive attention, owing to their excellent optoelectronic tunability and moisture stability compared with three-dimensional perovskite counterparts and show great potential for application in photodetectors (PDs). However, owing to the unavoidable grain boundary defects of perovskite polycrystalline films, the photocurrent is limited by poor light absorption and charge mobility. Therefore, the preparation of quasi-2D perovskite films with strong light trapping and high charge mobility has been challenging. In this study, novel broadband quasi-2D perovskite (BA)₂(FA)PbI₃ hybrid-structure PDs with good stability were fabricated by combining both monolayer graphene and Au square nanoarrays. The hybrid system using both graphene and Au square nanoarrays effectively improved the carrier mobility and light absorption and simultaneously maximized light trapping and light-induced carrier extraction, which resulted in PDs with greatly enhanced photocurrent in the visible and near-infrared range. The graphene-Au array-perovskite-based PDs had a low dark current of 10^-10 A, large on/off ratio of 10⁴, high responsivity of 18.71 A W^-1, and detectivity of 2.21 × 10¹³ Jones. The responsivity and detectivity were two orders of magnitude higher than those of PDs based only on perovskites. This work demonstrates a promising and feasible device based on the coupling of a gold array, layered graphene, and quasi-2D perovskites, which shows great potential for the development of high-performance broadband perovskite PDs.