Efficient Carrier Transport in 2D Bi 2 O 2 Se/CsBi 3 I 10 Perovskite Heterojunction Enables Highly-Sensitive Broadband Photodetection.

2D Bi ₂ O ₂ Se 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 Bi ₂ O ₂ Se photodetector with high performance and low-power consumption is limited by material synthesis method and the inherent high carrier concentration of Bi ₂ O ₂ Se. Here, a type-I heterojunction is presented, comprising 2D Bi ₂ O ₂ Se and lead-free bismuth perovskite CsBi ₃ I ₁₀ , for fast response and broadband detection. Through effective charge transfer and strong coupling effect at the interfaces of Bi ₂ O ₂ Se and CsBi ₃ I ₁₀ , 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 1.22×10 ¹² Jones at 808 nm. Moreover, efficient modulation of the dominant photocurrent generation mechanism from photoconductive to photogating effect leads to sensitive response exceeding 10 ³ AW ^-1 for heterojunction-based photo field effect transistor (photo-FETs). Utilizing the large-scale growth of both Bi ₂ O ₂ Se and CsBi ₃ I ₁₀ , the as-fabricated integrated photodetector array demonstrates outstanding homogeneity and stability of photo-response performance. The proposed 2D Bi ₂ O ₂ Se/CsBi ₃ I ₁₀ perovskite heterojunction holds promising prospects for the future-generation photodetector arrays and integrated optoelectronic systems.
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