Efficient Carrier Transport in 2D Bi₂O₂Se/CsBi₃I₁₀ Perovskite Heterojunction Enables Highly-Sensitive Broadband...

2D Bi₂O₂Se has recently garnered significant attention in the electronics and optoelectronics fields due to its remarkable photosensitivity, broad spectral absorption, and excellent long-term environmental stability. However, the development of integrated Bi₂O₂Se photodetector with high performance and low-power consumption is limited by material synthesis method and the inherent high carrier concentration of Bi₂O₂Se. Here, a type-I heterojunction is presented, comprising 2D Bi₂O₂Se and lead-free bismuth perovskite CsBi₃I₁₀, for fast response and broadband detection. Through effective charge transfer and strong coupling effect at the interfaces of Bi₂O₂Se and CsBi₃I₁₀, the response time is accelerated to 4.1 µs, and the detection range is expanded from ultraviolet to near-infrared spectral regions (365-1500 nm). The as-fabricated photodetector exhibits a responsivity of 48.63 AW^-1 and a detectivity of 1.22×10¹² Jones at 808 nm. Moreover, efficient modulation of the dominant photocurrent generation mechanism from photoconductive to photogating effect leads to sensitive response exceeding 10³ AW^-1 for heterojunction-based photo field effect transistor (photo-FETs). Utilizing the large-scale growth of both Bi₂O₂Se and CsBi₃I₁₀, the as-fabricated integrated photodetector array demonstrates outstanding homogeneity and stability of photo-response performance. The proposed 2D Bi₂O₂Se/CsBi₃I₁₀ perovskite heterojunction holds promising prospects for the future-generation photodetector arrays and integrated optoelectronic systems.