Manipulation of inter-particle interactions between TiO2 and CdTe: an effective method to enhance the performance of quantum dot sensitized solar cells

We have reported a pH-controlled deposition method to directly assemble aqueous 1-thioglycerol and 3-mercaptopropionic acid capped CdTe quantum dots (QDs) on mesoporous TiO2 thin films. The inter-particle interactions between CdTe QDs and mesoporous TiO2 could be modulated with the adjustment of solution pH values. Low amount of QD loading on the mesoporous TiO2 film was observed in the case of electrostatic attraction or strong electrostatic repulsion between CdTe QDs and TiO2. Only at weak electrostatic repulsion between CdTe QDs and TiO2 were high loading and uniform distribution of CdTe QDs obtained on the TiO2 film. Under an optimal condition, a power conversion efficiency of 0.76% was achieved for the CdTe QD sensitized solar cells under the standard illumination condition of simulated AM 1.5G (100 mW cm(-2)).