Drying and Coating of Perovskite Thin Films: How to Control the Thin Film Morphology in Scalable Dynamic Coating Systems

Hybrid perovskite photovoltaics combine high performance with the ease of solution processing. However, to date, a poor understanding of morphology formation in coated perovskite precursor thin films casts doubt on the feasibility of scaling-up laboratory-scale solution processes. Oblique slot jet drying is a widely used scalable method to induce fast crystallization in perovskite thin films, but deep knowledge and explicit guidance on how to control this dynamic method are missing. In response, we present a quantitative model of the drying dynamics under oblique slot jets. Using this model, we identify a simple criterion for successful scaling of perovskite solution printing and predict coating windows in terms of air velocity and web speed for reproducible fabrication of perovskite solar cells of similar to 15% in power conversion efficiency-in direct correlation with the morphology of fabricated thin films. These findings are a corner stone toward scaling perovskite fabrication from simple principles instead of trial and error optimization.

Automated summary

Hybrid perovskite photovoltaics have both high performance and ease of solution processing. However, the lack of understanding of the formation of thin film morphology in coated perovskite precursor films raises doubts about scaling up laboratory-scale solution processes. This study presents a quantitative model of drying dynamics under oblique slot jets, providing guidance on controlling this dynamic method for successful scaling of perovskite solution printing.