Great improvement of photoelectric property from co-sensitization of TiO2 electrodes with CdS quantum dots and dye N719 in dye-sensitized solar cells

The TiO2 film electrodes sensitized with CdS quantum dots (QDs) via chemical bath deposition method were successfully prepared as the photoanode of dye-sensitized solar cells (DSSCs). Microstructural characterizations by XRD, SEM, TEM and EDX show that the CdS nanocrystals with the cubic structure have intimate contact to the TiO2 films. The amount of CdS QDs can be controlled by varying the dipping time. The experiment results demonstrate that the CdS QDs-sensitized solar cells show a wider absorption in the solar spectrum and an enhanced surface photovoltage response. The maximal photoelectric conversion efficiency of 5.57% was achieved by the DSSC based on CdS QDs-sensitized TiO2 film with 4 min. The performance improvement is ascribed to the enhancement of electron transport, the reduction of electron recombination and the long electron lifetime.