Journal Article organic solar cells Polymers complementary absorption stability ternary solar cells 3D structure Fullerenes active layer air processing alkoxy side chains all‐photolithography all‐polymer solar cells antioxidant asymmetric solvent transport balanced mobility benzo[1,2-b:4,5-b′]difuran bioinspired blade coating crystallization kinetics device stability donor-acceptor materials gradient covalent organic framework membrane high mobility indoor photovoltaics intramolecular charge transfer effect ion‐gated transistors isomeric solid additives large bandgap polymers mechanical durability