Journal Article organic solar cells aggregation‐caused quenching coplanar structure deep‐blue emitter dimer acceptors exciton lifetime flexible conjugation‐broken linkers good mechanical properties intramolecular noncovalent interactions linearly fully fused acceptor−donor‒acceptor long‐term stability low‐volatility fused‐ring solid additive molecular design multiresonance thermally activated delayed fluorescence oscillator strength singlet-triplet energy gap solution‐processed organic light‐emitting diodes thermally activated delayed fluorescence trap density