Enhanced performance of dye/QDs cosensitized solar cells via Förster resonance energy transfer

In this report, CdS quantum dots (QDs) and N719/QDs cosensitized solar cells with ZnO/ZnS hierarchical structures as photoanodes are constructed. The ZnO/ZnS hierarchical structures consist of highly oriented ZnO nanorod arrays coated with ZnS nanoparticles (NPs), this construction is efficient on retarding the back transfer of electrons and inhibiting the recombination of electrons at the anode/sensitizers/electrolyte interfaces. The influence of deposition time for CdS QDs on photovoltaic performance of the ZnO/ZnS/CdS electrodes is explored and optimized photovoltaic performance is obtained from the device based on ZnO/ZnS/CdS(12) electrode, with a Voc of 0.66 V, a Jsc of 3.66 mA/cm2, an FF of 0.48, and a η of 1.16%. The cosensitized solar cell exhibits a 37% enhancement in energy conversion efficiency compared with the device sensitized by CdS QDs only, which is attributed to the higher light absorbance of the cosensitized solar cells than that of CdS sensitized solar cells.