Graphene quantum dots as hole transport material in lead free perovskite solar cell: a SCAPS-1D numerical study

The environment friendly, lead-free perovskite materials show significant promise for high-performance solar cells. We have conducted numerical simulations of the proposed solar cell structure using SCAPS-1D software. The analysed solar cell structure comprises of FTO/ZnO/MASnI3/GQD/C, where FTO serves as the transparent conducting oxide, ZnO as the electron transport layer (ETL), methylammonium tin iodide (MASnI3; MA = CH3NH3) as the absorbing material, graphene quantum dots (GQDs) as the hole transport layer (HTL), and carbon as the back contact. In this study, we examined various factors influencing solar cell performance, including thickness, Mott- Schottky and shallow acceptor density of the absorber layer. Additionally, we analysed the band energy, defect density at the GQD/MASnI3 and MASnI3/ZnO interfaces, carrier generation, recombination, and concentrations throughout the device layers. The optimized solar cell structure demonstrated an efficiency of 10.57%, a short-circuit current density of 34 mA cm-12, an open-circuit voltage of 0.9 V, and a fill factor of 88%. These simulation results could provide valuable guidelines for fabricating higher-efficiency, low-cost solar cells.