LAUSR

Abstract In this paper, Ag2Se quantum dots (QDs) are employed to solid-state dye-sensitized solar cells (DSSCs). By using a co-precipitation method, monodispersed Ag2Se quantum dots (QDs) with average sizes of 8.2, 9.2, 9.6, 10.5 and 11.6 nm are synthesized. By incorporation of Ag2Se QDs as light absorber and charge blocking layer in the photoanode, improved light harvesting and depressed electron recombination have been realized in DSSCs. The charge transport and recombination processes are found size-dependent, which directly determine the photovoltaic properties of DSSCs. The power conversion efficiency of the Ag2Se QDs (9.6 nm) based solid-state DSSCs is 5.89%, showing 200% enhancement compared to that of the controlled one (3.28%). The results demonstrate a practical solution for the carrier recombination defects in photoanode of DSSCs, and reveal the large potential of Ag2Se QDs for various inorganic/organic hybrid solar cells.