Photopolymerization initiated by aggregation-induced emission (AIE) dyes: Towards design of fluorescent photocatalysts with hybridized excited state

Abstract

Despite the truth that organic chromophores were deeply investigated as light-harvesting photocatalysts (PCs) or photoinitiators (PIs), innovative designs on the photoredox catalysts with specific photophysical/chemical characteristics, for instance, chromophores with clear hybridized excited state or aggregation-induced emission (AIE) are rarely reported to conduct visible-light induced polymerization. Here, we newly designed four chromophores as PCs in photopolymerization, with Donor-Acceptor structure and hybrid local and charge-transfer (HLCT) states, in order to provide diradicals with moderate concentrations while inducing the photopolymerization of acrylate monomers under separate light sources with different wavelengths. As results, moderate spin–orbit coupling (SOC) coefficients may assist to depress the retardation or inhibition of photopolymerization processes, which enables to efficiently induce free radical photopolymerization of acrylate monomer upon light irradiation. What’s more, two of them are recognized as typical AIE dyes, direct laser write experiments were thus performed on AIE dye-induced photopolymerization, especially for the water-soluble resin, poly(ethylene glycol) diacrylate (PEGDA), which seems to expand their applications in bio and medical fields as perspective.