Improving the photovoltaic performance of cadmium sulfide quantum dots-sensitized solar cell by graphene/titania photoanode

A mixed colloid of graphene and titania is synthesized by one-step hydrothermal reaction, thus a graphene/titania film photoanode is prepared. The graphene/titania film shows high porosity and specific surface area, which favors CdS quantum dots deposition on the film. On the other hand, the graphene/titania electrode has smaller electron transfer resistance and lower frequency peak than the pristine titania electrode, which indicates that the electron transport rate is increased by incorporating graphene into titania electrode. Under an optimal condition, the CdS quantum dots-sensitized solar cell based on graphene/titania photoanode achieves a light-to-electric energy conversion efficiency of 1.70%, which is increased by 57% compared with the solar cell based on the pristine titania electrode under a simulated solar light irradiation of 100 mW cm−2.

► A CdS QDs-sensitized solar cell with grapheme/TiO2 photoanode is prepared.
► Graphene/TiO2 electrode has large surface area and small recombination resistance.
► It favors the increase of electron transport and decrease of charge recombination.
► The efficiency of the cell is increased by 57% compared to the cell with TiO2 anode.