Preparation of novel TiO2 quantum dot blocking layers at conductive glass/TiO2 interfaces for efficient CdS quantum dot sensitized solar cells

TiO 2 quantum dots (QDs) are synthesized and used to prepare thin films as novel blocking layers (TiO 2 -QD-BLs) at conductive glass/TiO 2 interfaces by spin coating method. The electron recombination at conductive glass/polysulfide electrolyte interfaces can be reduced significantly after the insertion of TiO 2 -QD-BLs in the photoelectrodes. The effects of different thickness of TiO 2 -QD-BLs on photovoltaic performance of CdS QDs sensitized solar cells are investigated. It is found that the cells with 641 nm thick TiO 2 -QD-BLs show the highest power conversion efficiency of about 3.66% under full sunlight illumination (100 mW cm −2 , AM 1.5 G), which is obviously higher than that of the cells without TiO 2 -QD-BLs in the photoelectrodes (1.99%).