Simulation analysis of graphene contacted perovskite solar cells using SCAPS-1D

To understand what cause the low performance in a perovskite cell with graphene back contact, we have performed simulations of device characteristics using SCAPs-1D simulation platform. The impact of increasing defect concentration at the interface of perovskite/graphene (RGO) and also graphene thickness on the current density, voltage, fill factor, and conversion efficiency of the cell was investigated. We converted the graphene nanostructure to a planar p-type layer at the top side of the cell as a hole transporting layer in order to enable to insert it into the SCAPS simulation platform. The simulation analysis were compared to the experimental data reported in literature. The voltage and fill factor of the simulation and experiments are almost the same but the current density is showing to be higher in simulation analysis which reminds a imperfect thickness and absorption by the graphene layer. Graphene was also compared to Spiro-MeOTAD showing to be a promising materials to act as both hole transporting layer and back contact. The experimental process could be improved by looking at our results as a method to fabricate a high performance cell with graphene electrode. It is shown that such a hybrid structure suffers from imperfect interface at graphene and perovskite junction where a high concentration of trap density impedes the carrier collection.