Influence of synthesis parameters of N-doped graphene quantum dots and polymer composite layer on the performance of CIGS solar cells

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 degrees 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 eta is obtained for 60 degrees C. The Jsc and eta 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.

Automated summary

In this study, N-doped graphene quantum dots (N-GQDs) were used as luminescent downshifting layers to improve the performance of CIGS solar cells. A poly(methyl methacrylate) (PMMA) polymer-based matrix was used for mechanical strength and chemical stability. However, the PMMA layer caused photoluminescence (PL) quenching, so the N-GQDs/PMMA layer was annealed at different temperatures (20-80 degrees C) to obtain optimal performance. These layers were applied on top of the CIGS solar cells, resulting in enhanced Jsc and eta values. The best eta value was achieved at 60 degrees C.