Multicolor Photoluminescence from Nonconjugated Poly(3,4-dihydropyran) Nanoparticles

In recent years, nonconjugated organic luminophores arereceivingconsiderable interest from the scientific community, offering a newconceptual basis for the development of alternative photoluminescence-basedtechnologies. In this work, the polymerization of 3,4-dihydropyranwas exploited for the preparation of nonconjugated photoluminescentpolymer nanoparticles. Remarkably, excitation-dependent multicoloremission ranging from blue to yellow was observed in both solid andsolution. In contrast with similar materials, this behavior was notattributed to aggregation-induced emission, but rather to the presenceof independent, noninteracting chromophores located on the polymerstructure. Structural and optical characterizations along with furtherchemical modifications suggest that the emission is related to thepresence of acetal groups formed by ring-opening polymerization. Inaddition, it was shown that the removal of unsaturated structurescould enhance the photoluminescence quantum yield of the polymer (QY)up to 0.20 (lambda(ex) = 355 nm). This work provides a newtype of nonconjugated organic luminophore with both high QY and multicoloremission.