Preparation of metal halide perovskite solar cells through a liquid droplet assisted method

Abstract

Solution-processed organometal trihalide-based perovskites have attracted attention in the field of solar energy due to their high absorption and low temperature fabrication. We demonstrated the droplet-assisted two-step process of spin coating lead iodide (PbI 2) followed by spray coating methylammonium iodide (CH 3 NH 3 I) to prepare a continuous lead iodide perovskite film. A simple airbrush gun was used to control the volume of CH 3 NH 3 I, in order to attain a uniform, stoichiometric and continuous perovskite film. An insufficient or excess volume of CH 3 NH 3 I gives poor crystallinity and morphology, which gradually reduces the device performance. A power conversion efficiency (PCE) of 11.66% was achieved for 100 nm of PbI 2 followed by 300 μl of CH 3 NH 3 I and annealing at 100 °C for 120 min. To address the reproducibility of the device performance, 50 devices were fabricated for statistical analysis and 80% of the devices showed the average PCE of 10-11% with reproducible J SC, V OC and FF.