Simulation of CsGeI3-based perovskite solar cells using Graphene Oxide interfacial layer for improved device performance

In this paper, we have investigated the effect of the Graphene Oxide (GO) interfacial layer (IL) inserted between the absorber layer and Electron Transport Layer (ETL) in lead (Pb)-free all inorganic CsGeI3-based perovskite solar cells (PSCs) using solar cell simulator capacitance software (SCAPS-ID). The performance parameters of the FTO/Ti02/GO/CsGeI3/P3HT PSC device structure have been studied thoroughly, by changing the thickness of the active layer and IL, bulk defect density with defect energy levels of the absorber layer, band gap variation of the Graphene Oxide thin film and the variation of shunt and series resistance. It has been found that the introduction of GO interlayer in the PSC improved the device efficiency by ~ 6%. This is mainly due to the passivation of trap states (i.e. reducing charge recombination and ion migration), efficient band alignment and improved charge injection at the Perovskite/ETL interface. We have reported an optimized power conversion efficiency (PCE) (%) value of 20.03% for the proposed device structure and observed a remarkable improvement in performance parameters.