Facile fabrication of graphene devices through metalloporphyrin induced photocatalytic reduction

Solution processed graphene oxide (GO) sheets are electronically insulating and are generally reduced by chemical treatment or heat treatment in a reducing environment to recover their electronic properties, forming reduced graphene oxide (rGO). Here, GO sheets were photocatalytically reduced using 5-(4-hydroxyphenyl)-10,15,20-tri(p-tolyl) zinc(II) porphyrin (Zn(II)TTPOH) under ambient conditions. After illumination in the presence of a hole scavenger and Zn(II)TTPOH, the formation of rGO was confirmed through optical absorption measurements and monitoring of the D/G peak ratios from Raman measurements. The resultant rGO formed stable aqueous suspensions with the Zn(II)TTPOH. The electron transfer from photoexcited porphyrin to GO was studied through photoluminescence measurements. Utilising this photoreduction process as a post processing strategy, an increase in conductivity and an ambipolar field effect transistor (FET) behaviour were demonstrated on prepatterned GO devices. We have also confirmed the photoreduction process at low energy wavelengths (588 nm), indicating the versatility of using metalloporphyrins as photocatalysts for graphene oxide reduction.