Structural Refinement and Optoelectronic Properties of (MoxTi1-2xO2-δ)1-y(RGO)y Nanocomposites and Their Photovoltaic Studies with Natural Pigments as Sensitizers

Abstract

In the present investigation, the optoelectronic properties of the binary TiO2/RGO nanocomposites modified through the insertion Mo(VI) ions and thereafter these ternary nanocomposites (NCs) have been tested for I–V measurements using natural pigments as sensitizers. Initially, a series of (MoxTi1-2xO2-δ)1-y(RGO)y [x=0.5 to 3.0 mol %; y=0.75 wt.%] NCs was prepared by using in-situ chemical approach. XRD Rietveld refinement reveals the formation of single phase only with substitution of two Ti(IV) ions by single Mo(VI) ions in the ternary NCs. After the well characterizations, these NCs are deposited on the FTO substrate using binder-free doctor blade technique and then these are sensitized with N719 dyes (model protocol) as well as natural pigments and measured under solar simulator for knowing the photovoltaic performances. Among the different photoelectrodes, I–V and IPCE measurements of (Mo0.100Ti0.980O1.990)0.925(RGO)0.075 NCs sensitized with N719 showing the highest power conversion efficiency of 7.58% which is higher to that of TiO2/RGO (η=5.81%) based photoelectrodes. For the optimized photoelectrode composition with N719, natural pigment Betalain based dye sensitized solar cells (DSSCs) show the highest efficiency of 2.23% which opposes to an efficiency of 0.38, 1.29, and 1.13% for Lawsone, Curcumin and Anthocyanin sensitized DSSCs, respectively.