Low toxic Cu₂GeS₃/InP quantum dot sensitized infrared solar cells

Type-II Cu₂GeS₃/InP core/shell quantum dots (QDs) are designed using density functional theory and synthesized by a hot injection method in order to enhance the power conversion efficiency of quantum dot sensitized solar cells. The low toxicity and an absorption extending to the infrared region are key aspects of the importance of these QDs. The longer absorption achieved for type-II Cu₂GeS₃/InP QDs compared to single core Cu₂GeS₃ QDs is achieved by optimization of the band alignment. This leads to a more efficient carrier separation and a suppression of the electron-hole recombination. The results show that the efficiency and the electron injection rate constant increase by more than 5 and 2 times, respectively.