Dual aggregation-induced emission enhancement (AIEE) and crosslink-enhanced emission (CEE) driven via halogen-bond-assisted cocrystallization and radical solid-phase polymerization

Abstract

Halogen bonding (XB) was used to drive aggregation-induced emission enhancement (AIEE) and crosslink-enhanced emission (CEE) in a concurrent manner. Weak luminophores and vinyl monomers were cocrystallized via XB to drive AIEE, the obtained monomer cocrystal solids were subsequently polymerized via free-radical solid-phase polymerization (SPP) to drive CEE. Weak luminophores containing bromine (Br) and vinyl monomers containing nitrogen (N) or oxygen (O) were combined to form XB-based monomer cocrystals (Br⋯N and Br⋯O bonds), which exhibited AIEE, and the subsequent polymerization of the obtained cocrystals enabled the weak luminophores to be incorporated into the polymer matrix. The resultant restriction of the vibrational and rotational motions of the luminophores led to CEE. The obtained luminophore-embedded emissive sheets exhibited stimuli-responsiveness to temperatures, pH, and solvents, and served as stimuli-responsive emissive polymers. The sheets also served as host–guest interactive materials.