Synergistic effect of zinc selenide–reduced graphene oxide towards enhanced solar light-responsive photocurrent generation and photocatalytic 4-nitrophenol degradation

Herein, we report the in situ synthesis of zinc selenide (ZnSe)-decorated reduced graphene oxide (RGO) by a simple one-step solvothermal reaction for application in large-area, thin-film photodetector devices and photocatalytic 4-nitrophenol degradation. The photoresponsivity of the RGO–ZnSe photodetector is three orders of magnitude higher than that of controlled ZnSe. The ac transport mechanism in the composite reveals that its electrical conduction is modulated by a temperature-independent universal function. An EIS study confirmed the influence of RGO on the conductivity and charge transfer in the RGO–ZnSe composite. The photocatalytic degradation efficiency of the composite is four times higher than that of controlled ZnSe. In the RGO–ZnSe composite, RGO acts as a solid-state electron mediator, which efficiently collects the photo-induced electrons from the conduction band of ZnSe and subsequently hinders electron–hole recombination in ZnSe. This study explores the role of RGO–ZnSe synergy in achieving better photoresponse and photocatalytic performance. The RGO–ZnSe composite may lead to new possibilities in solar energy-harvesting applications and photocatalytic degradation of different non-self-sensitizing water pollutants.