Thermo-photoelectric coupled effect induced electricity in N-type SnSe:Br single crystals for enhanced self-powered photodetectors

Self-powered photodetectors (PDs) have attracted great attentions due to energy shortage and the upcoming internet of things. However, the bottleneck of traditional methods to enhance the output performances of self-powered PDs are largely limited. Here, we report a dramatic coupling enhancement (1 + 1 > 2) of the output signals in a bromine doped fin selenide (SnSe:Br) single crystal due to the thermo-photoelectric coupled effect for enhanced self-powered PDs. As compared with that of individually illuminating the device, both the output current and voltage signals of the PD can be enhanced by 38.1% and 81.9% under the simultaneous illumination at the top surface and cooling at the bottom surface, respectively. The coupling enhancement mechanism is associated with the same polarities of photoelectric and thermoelectric signals during the cooling process, where the photo-generated electrons can be accelerated by the driving force of the thermoelectric field under the cooling condition. This work offers a novel approach to enhance the output performances of self-powered PDs.