Nanoscale Control of Aggregation-Induced Emission and Second Harmonic Generation in a Dicyano Distyrylbenzene-Appended Polymer Using Optical Trapping.

We demonstrate nanoscale control over aggregation-induced emission (AIE) and second harmonic generation (SHG) by using optical trapping to manipulate a cyano-substituted distyrylbenzene (CDSB)-substituted polymer. The precise manipulation afforded by a tightly focused laser beam induces the formation of micrometer-sized polymer aggregates, demonstrating control over structure at the microscale. These aggregates exhibit yellow fluorescence with a prominent emissive species at 577 nm. Notably, further laser irradiation generates distinct aggregates characterized by blue fluorescence and strong SHG emission, indicating the formation of noncentrosymmetric microstructures with enhanced nonlinear optical properties. We elucidate the dynamics and mechanisms governing these disparate aggregation behaviors, highlighting the potential of optical trapping to control both AIE and SHG for the rational design of advanced functional microstructured materials and photonic devices, such as optical switches or frequency converters.