Reduced Graphene Oxide - Zinc Phthalocyanine Composites as Fascinating Material for Optoelectronic and Photocatalytic Applications

Reduced graphene oxide-zinc tetra tert-butyl phthalocyanine (RGO-ZnTTBPc) hybrid material has been synthesized through the reduction of graphene oxide (GO) in presence of ZnTTBPc. As-prepared RGO-ZnTTBPc thin film photodetector exhibited stable and reproducible photocurrent responses with a responsivity of 2 A/W under simulated solar light. A detailed study on electrical transport mechanism reveals the occurrence of phonon assisted quantum tunneling of charge carriers among the defect states present in RGO - ZnTTBPc system. The relaxation dynamics of charge carriers in the composite is modulated by a temperature independent universal function. Furthermore, the resulting hybrid material showed an enhanced photocatalytic activity with 3.5 times higher reduction rate constant over controlled ZnTTBPc towards the reduction of 4-nitrophenol under solar light irradiation. Superior photo-response property and photocatalytic reduction was attributed to the synergistic effect between favorable matching of the lowest unoccupied molecular orbital (LUMO) level of ZnTTBPc to the work function of conductive RGO. The present work is especially important in the field of RGO-based next-generation photocatalysts and light energy harvesting applications.