Efficiency and stability enhancement in FA-based perovskite solar cells using controlled reduction of graphene oxide interlayer - An experimental investigation

Reduced graphene oxide (rGO) as an interlayer and interface engineer, due to its conductivity and hydrophobicity, can be coated on top of perovskite layers to increase the photovoltaic performance and stability of perovskite solar cells. Herein, we employed reduced graphene oxide as an interlayer. By controlling the reduction level of rGO, its potential for boosting perovskite solar cells' efficiency was further increased. Results showed that increasing the reduction degree of rGO to an optimal level increased its conductivity and hole mobility, which induced charge transfer at perovskite/hole transport layer and increased the open-circuit voltage of solar cells. Our rGO reduction controlling strategy enables FAPbI3-based solar cells to record a PCE of 22.29%. In addition, increasing reduction degree increased hydrophobicity behavior of rGO. It increased perovskite solar cell resistance against humidity and heating degradation. The developed method in current study can push up perovskite solar cells to industrialization.