  We present a method to manipulate the final morphology of roll-to-roll
slot-die coated poly(3-hexylthiophene) (P3HT) by optically exciting the p-type
polymer in solution while coating. Our results provide a comprehensive picture
of the entire knowledge chain, from demonstrating how to apply our method to a
fundamental understanding of the changes in morphology and physical properties
induced by exciting P3HT while coating. By combining results from density
functional theory and molecular dynamics simulations with a variety of X-ray
experiments, absorption spectroscopy, and THz spectroscopy, we demonstrate the
relationship between morphology and physical properties of the thin film.
Specifically, in P3HT films excited with light during deposition, we observe
changes in crystallinity and texture with more face-on orientation and
increased out-of-plane charge mobility.
