High‐performance Self‐powered Ultraviolet‐visible‐near infrared Broadband Photodetectors Based on Sb₂Se₃/TiO₂ Heterojunctions and Multifunctional Applications

Abstract High‐performance broadband photodetectors (PDs) are essential components in spectroscopy, remote sensing, imaging, and light communication applications. In this paper, Sb₂Se₃ nanoparticles (NPs) are uniformly deposited on TiO₂ nanorod arrays (NRs) to construct a type II heterojunction with good interfacial contact by a simple two‐step potentiostatic electrochemical deposition method combined with N₂ atmosphere annealing at 280, 290 and 300 °C to control the amount of Se in Sb₂Se₃. A good interfacial contact between Sb₂Se₃ and TiO₂ is conducive to the separation and transport of photogenerated carriers. Sb₂Se₃/TiO₂ PDs exhibit excellent self‐powered photoresponse in a broad spectral range from ultraviolet‐visible‐near infrared (UV‐VIS‐NIR) due to the combined effects of high light absorption, low defect density, and more suitable band alignment. The optimal parameters with a responsivity of 13.48 A W⁻¹, detectivity of 7.9 × 10¹¹ Jones, and response time of 18/20 µs are demonstrated for the PDs annealed at 290 °C. The excellent performance broadband Sb₂Se₃/TiO₂ PDs are used to construct the application models in the light communication for light encryption and flaw detection. This work opens up a new strategy for Sb₂Se₃/TiO₂ PDs in multifunctional applications.