Multiple Exciton Harvesting at Zero-Dimensional/Two-Dimensional Heterostructures

Abstract

Heterostructures of zero-dimensional/two-dimensional (0D/2D) materials, especially quantum dots (QDs)/nanosheets (NSs), have attracted significant attention for extracting photogenerated electrons and holes. Herein, we report the dissociation of excitons at the heterojunction of CdSe (cadmium selenide) QDs and MoS 2 (molybdenum disulfide) nanosheet utilizing steady-state and time-resolved spectroscopic techniques. Quasi type II semiconductor-like band energy alignment of the 0D/2D heterojunction facilitates exciton breaking via hole transfer from the QD to MoS 2 . Furthermore, we demonstrate the extraction of two holes from doubly excited QDs (created via high-power excitation) following the dissociation of a biexciton at the 0D/2D interface. This work is expected to provide a new approach of exploiting multiple exciton generation in quantum dot-sensitized solar cells by harvesting multiple carriers.