An Additive of Sulfonic Lithium Salt for High-Performance Perovskite Solar Cells

摘要

The perovskite layer has an important influence on the photovoltaic performances of perovskite solar cells (PSCs). In order to improve the morphology and crystallinity of the perovskite film, the additive of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is introduced in the perovskite precursor solution. And the perovskite solar cell with architecture of FTO/compact TiO2/ mesoporous TiO2/CH3NH3PbI3/spiro-OMeTAD/Au is fabricated. By optimizing the concentration of LiTFSI, the fabricated PSC shows the best power conversion efficiency of 17.30% with a fixed device area of 1.5×1.5 cm2 under one sun illumination, while the device without LiTFSI introduction has an efficiency of 15.53% at the same test condition. The morphology observation and photoelectrical characterization demonstrate that the significant improvement of the device performance results from the charge carrier’s fast transportation and less recombination for larger grain sizes and fewer grain boundaries by doping LiTFSI into perovskite precursor solution.