Abstract
In this work, N-doped graphene quantum dots (N-GQDs) are used as luminescent downshifting layers, which enhanced the performance of the CIGS solar cells. For providing mechanical strength and chemical stability, a poly(methyl methacrylate) (PMMA) polymer-based matrix is used. However, the PMMA layer creates photoluminescence (PL) quenching, so N-GQDs/PMMA layer is annealed at various temperatures (20–80 °C) to obtain the best performance. These layers were applied on the top of the CIGS solar cells and the performance of the cell is evaluated. The best value of η is obtained for 60 °C. The Jsc and η values are enhanced to 36.03 mA/cm2 and 16.13% from 34.05 mA/cm2 and 14.70%, respectively. Furthermore, the PV cell parameters (photogenerated current density (Jph), shunt resistance (Rsh), series resistance (Rs), diode ideality factor (n), and reverse saturation current density (J0)) were also determined and analyzed to investigate the reduction in losses in the cell.
•Highly efficient N-doped graphene quantum dots (N-GQDs) were synthesized.•The N-GQDs/PMMA were synthesized at various temperature.•The conversion efficiency of the CIGS solar cell was improved (absolute) by 1.43%.