Boosting the performance of self-powered SnO2-based UV photodetectors via Bi doping modulation for UV imaging and optical communication

Ultraviolet photodetectors (UVPDs) are critical components in optical sensing and communication. The creation of self-powered UVPDs that are autonomous, highly efficient, and compact is key to advancing next-generation, energy-saving, and highly integrated photonic systems. However, their optical imaging and encrypted data-transmission abilities are limited by the inadequate separation and transport of photogenerated charge carriers in semiconductor photoanode materials. Herein, we report self-powered photoelectrochemical UVPDs (SPUs), with improved charge-utilization efficiency featuring flower-like Bi-doped SnO 2 nanostructures as their photoanode. The three-dimensional flower-like nanostructures are beneficial for light absorption. Bi doping provides donor states and oxygen vacancies in SnO 2 , and these promote the separation of photogenerated carriers and suppress interface-charge recombination through band bending at the SnO 2 /electrolyte interface. The developed device achieves a high on/off ratio of 25 812, a remarkable responsivity of 0.014 ​A ​W −1 , and an impressive detectivity of 1.637×10 11 Jones, with excellent cycling and environmental stability. More importantly, our device exhibited a rapid response time of 3 ​ms, to our best knowledge, which is the fastest value reported for SnO 2 -based SPUs to date. Benefiting from these advantages, the device was found to exhibit high-resolution imaging capability under 0 ​V bias and was successfully used as a self-powered light receiver for encrypted optical communication, highlighting its possible role as an integral detection units in multifunctional optoelectronic systems.