A pH-value sensitive and self-powered photodetector based on an anthocyanin/graphene heterojunction

Abstract

A biologically inspired anthocyanin-graphene hybrid heterojunction has been designed and demonstrated to serve as a highly pH-value sensitive and self-powered photodetector. The photosensor shows a photoresponsivity as high as 0.17 mA W⁻¹ at 0 V and it can reach a pH value sensitivity of up to 0.2 pH unit. The charge transfer and the built-in electric field at the heterojunction can account for the observed photoresponse. The active source material, anthocyanin, is obtained from nature, and it can be dissolved in water without causing pollution. Together with its self-powered capability, the pH-value sensitive photodetector represents an excellent eco-friendly device. In view of the current issues of energy shortage and environment pollution, our study shown here could be very useful and practical for next-generation technology developments.