Fig. 2

J-V curves for DSSCs under back illumination conditions over 10 days. The subfigures illustrate the performance variations of different configurations: (a) TPT, (b) \(\hbox {TP}_{0.05}\)T, (c) \(\hbox {TP}_{0.1}\)T, and (d) \(\hbox {TP}_{0.2}\)T. These curves highlight the impact of graphene doping on cell efficiency from the rear side of the panels, which is essential for understanding performance under less direct light conditions.