Ionic-bond crosslinked carbonized polymer dots for tunable and enhanced room temperature phosphorescence

Carbonized polymer dots (CPDs) have emerged as promising room temperature phosphorescent (RTP) materials owing to their tunable luminescence and facile synthesis. However, current strategies relying on hydrogen/covalent bond for luminescence enhancement suffer from limited phosphorescence intensity, and color diversity (primarily green). This work proposes constructing ionic-bond crosslinked network as a novel design strategy to address these limitations. Owing to the high strength, non-directionality and non-saturation of ionic bond, crosslinked networks are constructed to immobilize chromophores and suppress non-radiative transitions. By incorporating lithium ions into poly(acrylic acid)-based CPDs, the photoluminescence quantum yield is dramatically enhanced from 1.1 % to 48.4 %, with a 40-fold increase in phosphorescence intensity. Further introduction of zinc ions enables tunable RTP emission from green to yellow via transition metal doping. This strategy achieves effective regulation of RTP intensity and wavelength in CPDs, providing a versatile platform for designing advanced organic phosphorescent materials with tailored RTP properties.