Stability Enhancement in Perovskite Solar Cells with Perovskite/Silver–Graphene Composites in the Active Layer

For practical use of perovskite solar cells (PSCs) the long-term stability of devices should be ensured. The device stability is attributed to degradation of the perovskite molecule due to moisture and ion migration and thermal and light instability under sunlight illumination. To solve the stability issues, we proposed a new approach, i.e., fabrication of PSCs based on perovskite/silver nanoparticle-anchored reduced graphene oxide (perovskite/Ag-rGO) composites. The Ag-rGO in the composite not only suppresses the ion migration but improves the thermal and light stability. The composite-based solar cells thermally aged at 90 °C for 90 h sustained over 94% of the initial value of the power conversion efficiency (PCE), while a pristine PSC showed a 39% decrease in its initial PCE. More importantly, the long-term stability of composite-based PSCs was exceptional, retaining almost 100% of the initial values of performance parameters over 330 days under ambient conditions (i.e., 25–30 °C, 45–57% humidity).