Journal Article semitransparent organic solar cells Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. all-polymer solar cells covalent–organic framework crystallinity device architecture dimer acceptors efficiency excimer exciton flexible conjugation‐broken linkers flexural endurance good mechanical properties lifetime long‐term stability molecular ordering molecular packing organic solar cells self‐powered greenhouses solid additive spectral response ternary strategy thick-film devices through-hole transient absorption