Development of TiO 2 @rGO Nanocomposite-Based Photoanode for Improved Efficiency of Coffee-Based Dye-Sensitized Solar Cells

This work reports the synthesis of TiO 2 @rGO nanostructures for improving the efficiency of dye-sensitized solar cell devices. TiO 2 @rGO nanostructures were prepared using a co-precipitation-assisted method. The X-ray diffraction (XRD) investigations conveyed single-phase formation of TiO 2 and reduced graphene oxide (rGO) with crystallite sizes of 12 nm and 7 nm. The transmission electron microscopy (TEM), investigations revealed spherical and sheet-like morphology of TiO 2 and rGO, respectively. UV-visible absorption spectroscopy investigations revealed the higher absorption of the light with increasing weight percentage of rGOin the TiO 2 . The dye-sensitized solar cells (DSSCs) devices were prepared using the TiO 2 nanoparticles and TiO 2 @rGO nanocomposites as the working electrode, deposited on ITO, coffee extract as dye, and a candle flame produced carbon as a counter electrode. The pure TiO 2 -based DSSCs device could provide a power conversion efficiency (PCE) of 2.1% only. On the other hand, the TiO 2 @rGO (3 wt%) nanocomposites-based DSSCs device exhibited a superior PCE of 4.63%. The enhancement in the PEC of the TiO 2 @rGO based DSSC device is mechanistically discussed by considering the rGO-based higher light absorption and preventing the electron–hole recombination process.