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

Abstract

Abstract 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.