Synergic effect of graphene and core-shells structured Au NR@SiO₂@TiO₂ in dye-sensitized solar cells

Graphene and Au nanorods (AuNRs) coated with SiO₂@TiO₂ double shells (AuNR@SiO₂@TiO₂) were incorporated to form novel composite photoanodes in dye sensitized solar cells (DSSCs). The performances of the photoanodes and DSSCs are studied systematically. The short circuit current density (J _sc) and power conversion efficiency (PCE) of these composited DSSCs were greatly enhanced and the influences of the graphene, AuNRs and the SiO₂@TiO₂ double shells were revealed. The optimal properties with the maximal J _sc of 16.26 mA cm^-2 and PCE of 8.08% are obtained in the DSSC co-doped with graphene and AuNR@SiO₂@TiO₂, significantly higher than those of the conventional DSSC with pure TiO₂ photoanode by 37.7% and 32.9%, respectively. These significant enhancements in J _sc and PCE are attributed to the synergistic effect of graphene, the local surface plasma resonance of AuNRs, as well as the outer SiO₂@TiO₂ double shells, which result in the increased specific surface area and dye adsorption, the increased light absorption, the decreased charge transfer resistance R ₂ and electron recombination and thus the increased J _sc and PCE of the DSSCs.