Patterned Blade Coating Strategy Enables the Enhanced Device Reproducibility and Optimized Morphology of Organic Solar Cells

Morphology evolution kinetics at multi-scale regime is a challenging problem which is critical for industrial fabrication of high-performance organic solar cells (OSCs). An innovative strategy utilizing a patterned blade to print non-fullerene (NF) based devices in ambient conditions is demonstrated. A specially designed patterned blade with micro-cylinder arrays exhibit a reasonable control over the fluid flow at high extensional and shear strain rate to enhance lateral mass transport during blade-coating. Comparison of patterned and normal blade in printing polymer:NF blend film at different speeds reveals interesting avenues to optimize the blend films morphology. Patterned blade printed PM6:Y6 films yield a PCE of 15.93% as compared to 14.55% from a normal blade. Through in situ and ex situ morphology characterization techniques, the use of patterned blades induce conformational changes in PM6 chains, enabling Y6 to crystallize faster and more efficiently. Such improved blend morphology enables favorable charge transfer and transport to realize superior device performance. A lower stick-slip effect at the macro-scale with the patterned blade results in a smoother film promoting device reproducibility. Applications in efficient large-scale devices, confirming the choice of patterned blade design are reported. The efforts collaborating device engineering, morphology evolution kinetics would enable reproducibility and eased commercialization of OSCs at large scale.