Motion-dispensing as an effective strategy for preparing efficient high-humidity processed perovskite solar cells

Perovskite solar cells (PSC) are expected to make a market entrance soon but efforts devoted to reducing the production cost are still highly desirable. For that purpose, recent development of PSC has started to shift direction towards high-humidity processing to remove the use of inert gas filled-environment. However, fabrication of PSC in high-humidity condition is a challenging task as the presence of moisture considerably alters the growth kinetics of perovskite layer during film fabrication stage resulting in imperfect surface coverage and rough film. Therefore, this work demonstrates for the first time the applicability of motion-dispensing as a simple yet effective approach for the deposition of methylammonium iodide (MAI) solution in two-step spin-coating high-humidity-processed PSC. For comparison, static-dispensing approach is also developed by tuning the period of MAI solution remained stationary on the PbI layer to comprehend the morphological and optoelectronic properties of the PSC. It is discovered that motion-dispensing encourages the formation of smooth and pinholes-free perovskite film equipped with PbI passivation layer, thereby contributing to improved charge transfer and charge recombination dynamics. As a result, efficiency of up to 13.4% and 13.1% have been acquired for the respective mesoporous- and planar-based PSC fabricated in relative humidity (RH) 40–50%. 2 2