Enhanced performance of quantum dot solar cells based on type II quantum dots.

The characteristics of quantum dot solar cells (QDSCs) based on type II QDs are investigated theoretically. Based on a drift-diffusion model, we obtained a much higher open circuit voltage (Voc) as well as conversion efficiency in a type II QDSC, compared to type I QDSCs. The improved Voc and efficiency are mainly attributed to the much longer Auger recombination lifetime in type II QDs. Moreover, the influence of the carrier lifetime on devices' performance is discussed and clarified. In addition, an explicit criterion to determine the role of quantum dots in solar cells is put forward. [ABSTRACT FROM AUTHOR]