Yanghua Lu

Enhanced monolayer MoS2/InP heterostructure solar cells by graphene quantum dots

We demonstrate significantly improved photovoltaic response of monolayer molybdenum disulfide (MoS2)/indium phosphide (InP) van der Waals heterostructure induced by graphene quantum dots (GQDs). Raman and photoluminescence measurements indicate that effective charge transfer takes place between GQDs and MoS2, which results in n-type doping of MoS2. The doping effect increases the barrier height at the MoS2/InP heterojunction, thus the averaged power conversion efficiency of MoS2/InP solar cells is improved from 2.1% to 4.1%. The light induced doping by GQD provides a feasible way for developing more efficient MoS2 based heterostructure solar cells.

Multi-type quantum dots photo-induced doping enhanced graphene/semiconductor solar cell

A viable approach to enhance the photovoltaic performance of graphene (Gr)/semiconductor solar cells has been demonstrated. In order to take full advantage of the solar energy in the range of visible and ultraviolet light, InP and ZnO quantum dots (QDs) with band gaps of 2.4 eV and 3.3 eV, respectively, are simultaneously introduced to dope Gr by a photo-induced doping mechanism. Raman and photoluminescence measurements indicate that the photo-induced holes diffuse into Gr, leading to p-doping of Gr. As a result, the power conversion efficiency (PCE) of the Gr/GaAs heterostructure solar cell with good stability can be improved from 8.57% to 11.50%. Although this process is simple and feasible, we emphasize that the mixed semiconductor QDs enhanced Gr/semiconductor heterostructure solar cell is similar to the band gap engineering of traditional multi-junction bulk semiconductor solar cells.