High-Quality Conformal Homogeneous All-Vacuum Deposited CsPbCl₃ Thin Films and Their UV Photodiode Applications

A sensitive and fast ultraviolet (UV) photodetector is strongly desirable because of its wide range of applications in chemical/biological sensing and imaging. CsPbCl₃-based thin film photodetectors have not been constructed previously owing to their extremely poor precursor solubility; however, vapor deposition allows for thin film fabrication without the limitation of solubility. Therefore, this work is the first to demonstrate the optoelectronic properties of inorganic CsPbCl₃ perovskite thin films and UV photodiodes using all-vacuum deposition. The perovskites annealed at 120 °C exhibited outstanding performance, including a notable external quantum efficiency value of 797.1% with an applied bias of -2 V, an outstanding detectivity of 1.4 × 10¹³ Jones, a short response time as low as ∼ 50 μs, and a large linear dynamic range of up to 136 dB. CsPbCl₃ thin films manufactured by this vacuum-deposited approach were also found to be moisture-resistant and demonstrated high durability. The devices maintained excellent performance and demonstrated less than 10% degradation after 30 days. Thus, thin film visible-blind UV detectors can potentially be used in transparent smart displays, window-integrated electronic circuits, and sensor applications.