The morphologies and fluorescence quantum yields of perylene diimide dye-doped PS and PHVB microspheres

Aggregation and continuous π-stacking have been the major obstacles hindering the fluorescence (FL) quantum yield (Φ(F)) of perylene diimide (PDI) derivatives in the condensed phase. To prepare polymer microspheres with nearly unity Φ(F), in this work a POSS functionalized PDI derivative, POSS–PDI–POSS (PPP), was applied as the red fluorophore of poly(3-hydroxylbutyrate-co-3-hydroxyvalerate) (PHBV) and polystyrene (PS) microspheres. The electrosprayed PPP/PHBV and PPP/PS microspheres have unique hollow structures. Moreover, they show bright red FL under a fluorescence microscope. A photophysical study of the microspheres indicates a significant role of the polymer matrix in disrupting the aggregation state and the Φ(F) of the embedded PPP fluorophore. Both the PPP/PHBV and the PPP/PS microspheres show higher Φ(F) than most PDI materials in the condensed phase. The PPP/PHBV microspheres show Φ(F) of 28%, whereas the PPP/PS microspheres give nearly unity Φ(F).