In Situ Process Monitoring and Multichannel Imaging for Vacuum‐Assisted Growth Control of Inkjet‐Printed and Blade‐Coated Perovskite Thin‐Films

Vacuum-assisted growth (VAG) control is one of the most promising methods for controlling nucleation and crystallization of printed and coated large area lead halide perovskite-based layers for optoelectronics. To coat or print homogeneous high-quality perovskite thin-films at high fabrication yield, real-time process monitoring of the VAG is pivotal. In response, a 2.1-megapixel multichannel photoluminescence (PL) and reflection imaging system is developed and employed for the simultaneous spatial in situ analysis of drying, nucleation, and crystal growth during VAG and subsequent thermal annealing of inkjet-printed and blade-coated perovskite thin-films. It is shown that the VAG process, for example, evacuation rate and time, affects the film formation and provide detailed insight into traced PL and reflection transients extracted from sub-second videos of each channel. Based on correlative analysis between the transients and, for example, perovskite ink composition, wet-film thickness, or evacuation time, key regions which influence crystal quality, film morphology, and are base for prediction of solar cell performance are identified.