Emergent morphologies due to phase separation during meniscus-guided coating*

The active thin film layer in organic electronic devices are commonly manufactured from a solution using far out-of-equilibrium solution processing, such as meniscus-guided coating. The efficiency of these devices depends strongly on the phase-separated morphology that emerges spontaneously during manufacturing. Experimentally, meniscus-guided coating techniques allow in principle for control over both the characteristic size of the emergent morphology and the alignment of the morphology. However, an understanding of how the processing conditions impact on the emergent morphology remains lacking. Our theoretical work addresses this, and focusses on the combined effect of solvent evaporation and (hydrodynamic) transport processes that take place during the coating process, which we couple to a phase-field model to describe phase separation. Our findings reveal that both the initial decomposition process and late-time coarsening of the structures are affected by the coating conditions.