Charge transport dynamics of a C6H4NH2CuBr2I/TiO2 heterojunction in aqueous solution under reverse bias

The photocurrent output of the C6H4NH2CuBr2I/TiO2 heterojunction photoelectrode in an aqueous solution is super stable even after 30 000 s. However, the photocurrent is extremely weak. Intensity-modulated photocurrent spectroscopy revealed that the electron transfer in the C6H4NH2CuBr2I/TiO2 photoelectrode without bias is not sufficiently fast to compete with the charge recombination process due to the short diffusion length (similar to 23 nm), resulting in a low photocurrent. The charge separation and charge transfer efficiency in the bulk of C6H4NH2CuBr2I could be significantly improved under a small reverse electric field (E-r), resulting in an enhanced photocurrent.

Automated summary

The photocurrent output of the C6H4NH2CuBr2I/TiO2 heterojunction photoelectrode is super stable in an aqueous solution for 30,000 seconds but is extremely weak. The electron transfer is not fast enough to compete with charge recombination due to short diffusion length, resulting in low photocurrent. However, the use of a small reverse electric field significantly improves charge separation and transfer efficiency, leading to enhanced photocurrent.