Plasmon Enhanced Photovoltaic Performance in Graphene Oxide-TiO2 Composite Based Dye-Sensitized Solar Cells

Dye sensitized solar cells (DSSCs) have engendered great research interest with promising potentials in solar cell technology for their high power conversion efficiencies. In this study, we report a plasmon enhanced reduced graphene oxide (RGO)-TiO₂ nanocomposite electron injection layer towards the improved performance of DSSCs. Graphene oxide was synthesized using modified Hummer's method and further treated with hydrazine hydrate to obtain reduced graphene oxide (RGO). Structural and morphological properties of as synthesized RGO, RGO- TiO₂ and RGO-TiO₂-Au nanopaticle (Au NP) composites were investigated using Raman spectroscopy and ultra-high resolution transmission electron microscope (UHRTEM). Raman mapping was performed to further characterize the composite photoanodes.. Photovoltaic performance of DSSC containing composite photoanodes were studied, on keeping the RGO concentration constant and varying the Au NP concentration. A systematic increment in the short circuit current density was noticed while the open circuit voltage (V_OC ~ 0.72 V) of DSSC was observed to be constant by increasing Au NP concentration up to an optimal value, probably due to the combined effect of slight rise in quasi-Fermi level and higher carrier transport rate in the resultant composite. Thus, a significant enhancement in the overall photovoltaic performance was observed in DSSCs with RGO- TiO₂-Au NP composite photoanode.