Enhanced Sn-based perovskite solar cells with PEDOT:PSS layer doped with edetate disodium

High-quality PEDOT:PSS layer plays an important role in achieving efficient FASnI3 perovskite solar cells. To overcome the defects of the conventional PEDOT:PSS layer, edetate disodium (EDTA-2Na) was applied as the dopant into the PEDOT:PSS solution to modify the film quality. By characterizing the surface morphology and the analysis of the bulk crystallization, it reveals that the incorporation of EDTA-2Na can efficiently optimize the surface morphology, surface energy state and the grain size of the perovskite crystals. Therefore the open-circuit voltage of the perovskite devices can be improved, which as a result leads to the enhancement of the overall device performance as long as the doping concentration of EDTA-2Na was optimized.