All‐Inorganic Perovskite Photodetectors with Ultrabroad Linear Dynamic Range for Weak‐Light Imaging Applications

Abstract Linear dynamic range (LDR) and weak‐light detection limit of photodetectors (PDs) directly determine the imaging resolution and signal‐to‐noise ratio (SNR) in weak‐light condition. Herein, an all‐inorganic perovskite PD is designed with a sandwich structure of NiO_x/CsPbBr₃/TiO₂ (NCT). The CsPbBr₃ perovskites are designed by a spin‐coating method, and NiO_x and TiO₂ layers are introduced by an atomic layer deposition (ALD) method. The optimized NCT PD exhibits outstanding performance with ultralow dark current (≈10⁻¹¹ A), broad LDR (186.7 dB), and ultralow detection limit (857 pW cm⁻²). Significantly, a proof‐of‐concept optical imaging system has been demonstrated using the NCT PD as the sensor element, which shows high resolution and high SNR even under weak‐light condition. Furthermore, as a demo application, a solution is provided to the identification problem of 2D barcode under a weak‐light environment as low as 4 nW cm⁻². The results show promising applications of the all‐inorganic perovskite PD serving as a weak‐light imaging sensor, with unique potential for low‐cost manufacturing of large‐area optoelectronic devices.