Improving the Operational Stability of the Sb₂Se₃-Based Self-Powered Photodetector via Interfacial Engineering

Originating from photovoltaic devices, self-powered photodetectors (SPPDs) have low power consumption and show promising applications in photoelectric imaging and optical communications. Many efforts have been devoted to improving their photodetection performances, including responsivity, detectivity, and response time. However, work on their operational stability, one of the key parameters of applied PDs, is still rare. Here, using an interfacial engineering method, we improve the operational stability of the representative Sb₂Se₃-based SPPD. The Sb₂O₃ modification layer is applied at the interface between the Sb₂Se₃ and TiO₂ layers and characterized systematically. With the optimized fabrication of the Sb₂O₃ layer, the operational stability under both air ambient and underwater conditions is significantly enhanced. Moreover, the performances of the SPPD, including responsivity, detectivity, and response time, are improved to 0.45 A/W, 2.70 × 10¹³ Jones, and 81.5/75.0 ns, respectively. Specifically, without encapsulation, the photoresponse and key photodetection parameters of the devices vary by only around ten percent after working underwater. Our work provides a facile and effective way to modify the interfacial properties of the Sb₂Se₃ heterostructure and improve the operational stability of the SPPD.