Blue phosphorescent solid supramolecular assemblies between hydroxypropyl-β-cyclodextrin and triazine derivatives for achieving multicolor delayed fluorescence

Abstract

Highly efficient blue phosphorescent solid supramolecular assemblies are constructed by three triazine derivatives with different carboxylate substitution positions (TAB, TAC and TAD), hydroxypropyl-β-cyclodextrin (HPCD) and polyvinyl alcohol (PVA). The encapsulation of HPCD to TAB/C/D effectively promotes phosphorescence lifetimes and quantum yields of the guests by the host-guest interaction and hydrogen bonds suppressing the nonradiative decays. Impressively, TAD-HPCD/PVA with blue phosphorescence boasts an ultrahigh phosphorescence quantum yield (Φ_P) of 71.65 %. By further separately doping with fluorescent dyes Fluorescein sodium, Rhodamine B and Sulfo-Cyanine5, supramolecular polymeric films with water responsiveness, regulable lifetimes and multicolor delayed fluorescence are obtained via triplet-to-singlet and singlet-to-singlet Förster resonance energy transfer. Polymeric phosphorescence supramolecular materials mediated by HPCD are desirable for optical anti-counterfeiting patterns and information encryption.