Optimizing the performance of perovskite-based organic solar cells via graphene integration as the hole transport layer: a comprehensive analysis

Perovskite solar cells (PSCs), despite achieving efficiencies above 25\%, face concerns about structural stability due to organic compounds. This study focuses on modeling a stable, inorganic PSC using CsGeI₃ within the SCAPS-1D framework. Employing carbon-based electron transport layers and copper-based hole transport layers, along with graphene integration, enhances electrical and thermal conductivity. Among four configurations, the n-perovskite/perovskite/CZTSSe/Gr arrangement exhibits promising results: 1.1377VV_oc, 22.62mA/cm²J_sc, 87.42\% fill factor, and a 22.50\% power conversion efficiency. The analysis explores factors impacting performance, such as quantum efficiency, electric field strength, interface properties, layer characteristics, doping concentration, and temperature. It also evaluates resistance factors, interface defects, and the influence of reflection coatings, presenting a comprehensive understanding of the introduced efficient PSC configuration in the context of inorganic materials, especially those with cesium incorporation. Graphical abstract: (Figure presented.)