Green synthesis of TiO2 nanoparticles using Citrus limon juice extract as a bio-capping agent for enhanced performance of dye-sensitized solar cells

Abstract

TiO2 nanoparticles are considered as the prominent photoanode materials for dye-sensitized solar cells (DSSCs). We report herewith synthesis of TiO2 nanoparticles using Citrus limon juice extract which serves as a green-capping agent to control the shape, size and agglomeration behavior of the growing TiO2 NPs. The structure, size, morphology and optical properties of as-synthesized TiO2 NPs were characterized by XRD, RAMAN, HRSEM, HRTEM and UV-Vis measurements. The surface area and porosity were investigated by BET analysis. The Electrochemical impedance spectroscopy (EIS) assessment revealed the higher electron injection, greater charge collection efficiency and enhanced electron lifetime for the TiO2 obtained with 0.45% (v/v) capping agent (C′-TNP). The DSSC fabricated with C′-TNP photoanode exhibited greater light-to-current conversion efficiency, 4.55% compared to un-capped TiO2 nanoparticles (TNP), 1.31%. Citrus limon has been used as a natural source of citric acid and enhanced performance of dye-sensitized solar cells (DSSCs) are observed with capped TiO2. The better performance of DSSC resulted due to reduction in size, higher surface area and pore size, enlarged band-gap and greater dye loading. This work demonstrated that the Citrus limon juice extract can play a vital role in the improvement of the DSSCs performance without any harmful impacts on the environment.