(Invited) How Beneficial Is Reduced Graphene Oxide (RGO) for Long-Term Photo Generated Charge Transport in Inorganic Oxide - Rgo Nanocomposites? a Case Study of Bismuth Titnate - Rgo Films?

Abstract

This work begins with a summary of the role of reduced graphene oxide (RGO) in promoting the photoactivity of oxides and chalcogenides. Initial indicators suggest that RGO is a good material for promoting charge speration over short time scales. However the story over long term illumination is different. This presentation delineates the results of a systematic analysis of the photoelectrochemical (PEC) and optical responses of RGO combined with a representative multimetal oxide – bismuth titanate (BTO) on films. We investigated the role of RGO as a promoter of charge separation and transport, by suppressing recombination loss of carriers in BTO. The micro-structure of the BTO/RGO composite observed using transmission, scanning electron, and atomic force microscopy, revealed a well-integrated, and highly porous morphology compared to pristine BTO film. The integration of BTO with RGO resulted in a ~ 7 fold increase in photocurrent density with an optimal RGO loading of 2 wt%. The performance of the BTO/RGO interface was further examined to obtain critical insights on: (i) how the electrolyte influences the stability of the BTO/RGO composite and (ii) what interactions prevail at the BTO/RGO interface, under long-term illumination to impact the RGO stability. This work assumes immediate significance because implementation of RGO as a charge transport agent in oxidative systems is heavily researched currently. Unless a mechanism to protect RGO is determined, its long-term stability, especially under oxidative conditions of any form, has to be thoroughly investigated on a case-to-case basis to ensure composite longevity.