High-Performance Simple-Structured Planar Heterojunction Perovskite Solar Cells Achieved by Precursor Optimization

Abstract

Planar perovskite solar cells (PSCs) with perovskite and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) heterojunction have attracted much interest because they can be fabricated by a low-temperature process and exhibit high power conversion efficiency (PCE). Various compositional engineering and interface engineering approaches have been applied to produce high-performance PSC devices. In this study, we found that high-quality lead halide crystal precursor has a significant effect on the perovskite film quality and it could enhance perovskite film light absorption, reduce crystal defects, and suppress charge recombination, resulting in enhanced device performance (from 8.9 to 15.0% for CH3NH3PbI3 and from 14.2 to 18.0% for MA0.7FA0.3PbI3-xClx). Moreover, electron and hole interlayer free devices were achieved by using high-quality PbI2 crystals and the devices exhibited a high PCE of 13.6 and 10.4% for glass and flexible substrates, respectively. This is important for simplifying the perovskite solar cell fabrication process without complex interface engineering involved, especially for printed PSCs.