Graphene Modified FTO/TiO2 Interface Photoelectrode for Improved Performance of Dye Sensitized Solar Cells.

The microstructure of photoelectrode plays a crucial role in the performance of Dye Sensitized Solar Cells (DSSCs). The uneven morphology of FTO (Fluorine doped tin oxide) glass and high porosity of TiO₂ layer will produce defects such as tiny gaps, pores and cavities in FTO/TiO₂ interface which allows for direct penetration of the electrolyte to the surface of FTO, leading to the recombination of electrons. To address this issue some work has been conducted to functionalize FTO glass with graphene because of its exceptional mobility and transparency. However, this approach is not feasible as graphene nanosheets is economically quite expensive. Therefore, in the current study, graphene nanosheets is replaced with graphene nanoplatelets (GNPs) in order to modify the FTO/TiO₂ interface by providing conducting bridges to photo-injected electrons and impede the excessive penetration of the electrolyte. The conversion efficiency for GNP modified interface was found to be 2.32% (active area of 1 cm2), which is 19.75% higher than the conventionally prepared DSSC. Electrochemical Impedance Spectroscopy (EIS) spectra revealed that the GNP based cell has lesser total internal resistance compared to the conventional one. [ABSTRACT FROM AUTHOR]