O, N co-doped CuCrO2 as efficient hole transport layer for high-performance ultraviolet photodetectors

The optoelectronic properties and film-formation characteristics of CuCrO2 are optimized through oxygen (O) and nitrogen (N) co-doping using the space-limited domain annealing method in ambient air. After O, N co -doping at 100 degrees C, the conductivity of CuCrO2 is enhanced due to a decrease in trap-state density and an in-crease in hole concentration, thereby facilitating carrier transport. With a work function (WF) of 5.24 eV and an electron affinity (chi) of 2.29 eV, the CuCrO2 films serves as both a hole transport layer (HTL) and an electron -blocking layer, playing a pivotal role in enhancing photogenerated holes extraction while suppressing non -radiative charge recombination at the heterojunction interface. Consequently, the responsivity and detectivity of the device with FTO/TiO2 NRs/O, N co-doped CuCrO2/Au structure reach 188 mA W-1 and 3.14 x 1013 cm Hz1/ 2 W-1 in self-powered mode, respectively. Simultaneously, the rise/decay time is reduced to just 31.2/32.1 ns. Furthermore, after applying a bias of -2 V, the photodetector demonstrates significantly improved performance with a responsivity of up to 5 x 105 mA/W (365 nm, 0.97 mW cm-2) and an apparent quantum efficiency of-30,000%. These results highlight the promising potential of utilizing O, N co-doped CuCrO2 HTL for con-structing high-performance optoelectronic devices.