Application of graphene in dye and quantum dots sensitized solar cell

The incorporation of graphene-based materials into solar cell represents a cost-effective option to boost its stability, optical transmittance and the overall performance. Graphene has been used as transparent window and counter electrodes, interface layers, hole/electron transport material and also as a buffer layer to slow-down charge recombination in solar cell. Prioritized concern for efficient graphene-based material for dye sensitized solar cell (DSSC) and quantum dots sensitized solar cells (QDSSC) has been motivated by the quest for efficient and low-cost solar cell. Conventional organic dye in DSSC was replaced with stronger light absorber quantum dots (QDs) material in QDSSC to absorb wider spectral wavelength so as to improve photo response in the solar cell. In this review, the application of graphene in DSSC and QDSSC was discussed. Promising properties of graphene has shown to enhance various layers of a solar cell. Although layer-by-layer chemical process can detach sections of graphene, this can be improved by doping. Conversion of graphite to graphene enhances the conductivity of photoexcited electrons, electron mobility and reduces the recombination rate of electron/hole pairs. The tunable bandgap properties and excellent thermal and mechanical stability of graphene facilitate the transfer of electrons. RGO improves electron lifetime by increasing the chemical capacitance and decreasing the resistance.