Air-assisted flow and two-step spin-coating for highly efficient CH 3 NH 3 PbI 3 perovskite solar cells

There is a multitude of reports on different methods of fabricating organic–inorganic halide perovskite films for high-efficiency solar cells. In this study, planar heterojunction (PHJ) CH 3 NH 3 PbI 3 perovskite solar cells were prepared by the two-step spin-coating method. The uniformity of the perovskite light-absorbing layer is enhanced by air-assisted flow (AAF). We compared the photovoltaic performance characteristics of films prepared with and without AAF. Perovskite solar cells constructed without AAF showed a power conversion efficiency (PCE) of 8.67%, whereas a higher PCE of 13.28% was obtained with an AAF-based perovskite solar cell. Our study presents a useful technique for preparing high-quality perovskite films.