Planar Perovskite Solar Cells using CH3NH3PbI3 Films: A Simple Process Suitable for Large-Scale Production

Despite the rapid progress of the power conversion efficiency (PCE) of perovskite solar cells, the reproducibility, stability, and large-scale production are major challenges. Here, we present a simple and quick solution-depositing process to achieve high-quality perovskite films by adding an insulating polymer of polyacrylonitrile (PAN) as a film-forming additive into the CH 3 NH 3 PbI 3 solution. With the CH 3 NH 3 PbI 3 :PAN films serving as an active layer, planar heterojunction perovskite solar cells show a PCE of 13.08 % at an area of 0.12 cm 2 and 7.32 % at a large area of 1.0 cm 2 . The PCE loss is only about 40 % from the small-area to larger-area devices fabricated by using a solution-based deposition process. The measurements were performed in air without any device encapsulation. We also used the conjugated polymer poly(3-hexylthiophene) (P3HT) as the alternative for PAN. The device performance indicates that the conjugated polymer is unsuitable as the additive, which we attribute to the photo-induced charge transfer between CH 3 NH 3 PbI 3 and P3HT.