Energy Band Engineering Drives Efficient and Stable Self-Powered Ultraviolet Photodetectors

Halide perovskites have attracted tremendous attention in optoelectronic devices due to their excellent photophysical properties. However, they are prone to photodegradation under ultraviolet (UV) light, limiting their applications in UV photodetectors (PDs). Here, energy band engineering is adopted to achieve efficient and stable perovskite UVPDs, in which the band gap of the CsPbCl3 microcrystals (MCs) is regulated by Rb doping. The fabricated Cs_0.84Rb_0.16PbCl₃ MC film exhibits wider bandgap and improved optical properties. Finally, under 365 nm light, the Cs_0.84Rb_0.16PbCl₃ perovskite PDs show superior UV detection performance including an open-circuit voltage of 0.84 V, an on-off ratio of 2.81×10⁶, a responsivity of 0.6 A/W and a detectivity of 3.48×10¹² Jones. Moreover, the PDs exhibit outstanding stability to UV light and temperature. This work provides a new strategy for the fabrication of high-performance perovskite UVPDs.