Polymer Crystallization Controls Cyano-OPV Assembly for High-Performance Solid-State Fluorescence

Cyano-substituted oligo(<i>p</i>-phenylenevinylene) derivatives (cyano-OPVs) demonstrate superior photophysical properties in solution with photoluminescence quantum yield (PLQY) of up to 87% yet experience severe aggregation-caused quenching in the solid state (PLQY typically 20%-40%), fundamentally limiting their practical implementation in optoelectronic devices. Here, we present a novel approach to enhancing the solid-state PLQY of cyano-OPVs by harnessing polymer crystallization through supramolecular interactions. We designed and synthesized a 2-ureido-4[1<i>H</i>]-pyrimidinone (UPy)-functionalized cyano-OPV derivative (UPy-OPV-UPy) and incorporated it into a crystallizable UPy-terminated poly(butylene succinate) (PBS-UPy) matrix. Systematic investigation of the photophysical properties and isothermal crystallization kinetics of PBS-UPy/UPy-OPV-UPy blends revealed a remarkable solid-state PLQY of approximately 97%, surpassing both traditional solid-state fluorescent materials and solution-state performance. This unprecedented enhancement is attributed to the effect of crystallization-driven supramolecular reorganization, which disrupts unfavorable fluorophore aggregates. This nondestructive approach offers a new paradigm for designing high-performance solid-state emissive materials, potentially overcoming the persistent challenge of aggregation-caused quenching that typically limits solid-state fluorescent material performance.