N, S-doped carbon quantum dot for long persistence phosphor assisted all-weather solar cells

Abstract

Traditional solar cells can only work during the daytime. The solar cells that can harvest energy in all weather conditions are favorable to solving the energy crisis and ecological issues. We present a novel quantum dot-sensitized all-weather solar cell (AW-SC) that can harvest energy in both day and night conditions. The AW-SC consists of a TiO2/long persistence phosphor (LPP) photoanode sensitized by nitrogen and sulfur co-doped carbon quantum dots (N, S-CQDs) and a Pt counter anode. The N and S doping reduces the band gap of CQDs and enhances the charge injection into the TiO2 layer, resulting in better solar cell performance. The LPP enables the AW-SC to store unabsorbed light from visible to infrared wavelengths and emit green fluorescence to excite the N, S-CQDs in the dark. The optimal AW-SC achieves a power conversion efficiency (PCE) of 18.7% in the dark.