• Dileep, R.K.; Maticiuc, N.; Mathies, F.; Levine, I.; Dagar, J.; Paramasivam, G.; Mallick, S.; Rao, T.N; Unger, E.; Veerappan, G.: Hybrid Aromatic Fluoro Amine Modified SnO2 Electron Transport Layers in Perovskite Solar Cells for Enhanced Efficiency and Stability. Solar RRL early view (2024)

Open Access Version

SnO2 is a widely used electron-transporting layer in perovskite solar cells. Despite the high compatibility with the perovskite absorber layers the presence of traps at the perovskite|SnO2 interface results in performance losses, hence their modification to improve the performance and stability of PSCs is therefore important. In this study, we enhanced the SnO2 ETL by incorporating a bi-functional aromatic amino fluorine molecule into the SnO2 precursor solution. The fluorine molecule was found to partially substitute the Sn and alter the energy levels while the aniline group aided in regulating the nucleation/growth rate of the perovskite crystalline films. In this work, a hole transporting material-free carbon-based PSCs (CPSCs) was fabricated. We found that perovskite absorber layers deposited on these modified SnO2 hybrid layers have higher optoelectronic quality, resulting in enhanced photovoltaic performance, device stability, and reduced hysteresis in CPSCs. Devices made with the modified hybrid SnO2 layers exhibited PCEs of 15.6% significantly better than unmodified SnO2 with 13.5%. CPSCs with these modified SnO2 films also exhibited remarkable retention of 88.7% of their initial power conversion efficiency for a shelf-life period (ISOS-D1I) exceeding 1200 h. This study presents a generic approach to enhance the stability and performance of CPSCs by modifying the properties of the electron transport layer and, consequently, regulating the quality of the perovskite material.