Additive-regulated one-step dynamic spin-coating for fabricating high-performance perovskite solar cells under high humidity conditions

Due to the humidity sensitive nature of the lead halide perovskite materials, high-performance perovskite solar cells (PSCs) can only be fabricated in glove boxes with inert gas protection. This work introduces a simple and environmentally less sensitive strategy for preparing high-performance PSCs. To start with, high-quality vertically aligned perovskite films are prepared with the one-step dynamic spin-coating method. The fabrication processes are completed under high humidity conditions. Besides, the anti-solvent treatment is not needed during our dynamic spin-coating, which simplifies the fabrication process. Additionally, methylammonium acetate (MAAc), ammonium thiocyanate (NH₄SCN), and ammonium acetate (NH₄Ac) have been introduced to regulate the growth of the solution-processed perovskite films. Shown on the in situ ultraviolet-visible absorption spectrum, the additives have a significant impact on the nucleation speed and intermediate growth rate of the perovskite films. Finally, with a relative humidity (RH) of 45%, MAAc-regulated PSCs with the MAPb(I_1−xBr_x)₃ formula show a maximum power conversion efficiency (PCE) of 19.09%. Besides, the MAAc-regulated devices retain 80% of their initial PCEs after more than 500 hours of storage under 40% RH conditions. This simple one-step dynamic spin-coating method introduced in this work reduces the environmental sensitivity of PSCs during device fabrication, which will be helpful for the industrial-scale fabrication of PSCs.