Journal Article morphology Fermi-level pinning PCPDTBT (poly{[4,4-bis(2-ethylhexyl)-cyclopenta-(2,1-b;3,4-b')dithiophen]-2,6-diyl-alt-(2,1,3-benzo-thiadiazole)-4,7-diyl}) PEDOT:PSS Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Review TEMPO Thiophenes bilayer actuators charge generation charge injection charge transfer states click chemistry contact resistance crystallization curvature prediction driving force electron paramagnetic resonance excess energy geminate recombination humidity trigger interfaces low bandgap polymers mechanical properties modular platforms organic solar cells organic transistors poly(3-hexylthiophene)