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Albeit high-quality QDs can be feasibly obtained relying on the well-developed organometallic high-temperature synthetic route,it is still a great challenge to immobilize the pre-prepared QDs on mesoporous oxide film electrodes with a high surface coverage.A modified post-synthesis assembly approach,ex situ ligand exchange route,has been developed for the effective deposition of QDs sensitizers(including CdSe,inverted type-Ⅰ core/shell structured CdS/CdSe,alloyed CdSexTe1-x,and type-Ⅱ core/shell structured CdTe/CdSe QDs)on TiO2 mesoporous film and PCEs of 5.42%,5.32%,6.36%and 6.76%are obtained for corresponding cell devices.1-4 Linker molecules mercaptopropionic acid(MPA)capped water-soluble QDs were prepared via ex situ ligand exchange from the initial oil-soluble QDs and then immobilized on TiO2 film electrodes by immersing the electrode into MPA-capped QD aqueous dispersions.The deposition of QD on TiO2 film is very fast and approaches the saturation loading amount within 2 h.The coverage of QD on TiO2particle surface is 34%.The uniformity of QD deposition is confirmed by elemental mapping within the cross-section of the film.With combination of high-quality QD sensitizers and the effective deposition technique for high surface coverage of sensitizers,the CdTe/CdSe type-II core/shell QD based QDSCs show a record photovoltaic performance with PCE of 6.76%under simulated AM 1.5,full 1 sun illumination,which is the highest reported to date for liquid junction QDSC.This result situates the sensitized technology in the same range of efficiencies reported with other complicated configurations for QD solar cells.