Thermal Activated Reversible Phosphorescence Behavior of Solid Supramolecule Mediated by β‐Cyclodextrin

Abstract A reversible solid thermally responsive deep‐blue pure organic room temperature phosphorescent material is constructed by terephthalic acid (PPA), β ‐cyclodextrin ( β ‐CD), and poly(vinylalcohol) (PVA). Attributed to the host‐guest interaction of β ‐CD to isolate PPA chromophore and the rigid environment offered by hydrogen bonds to suppress the nonradiative decays, amorphous supramolecular assembly PPA‐CD/PVA not only induces a deep‐blue phosphorescence at 410 nm that differing from traditional PPA derivatives with green emission but also enhances the quantum yield up to 30.52%. Uncommonly, this film exhibits a unique reversible thermal stimulation response property with blue and cyan phosphorescence color transitions because heating can destroy the binding behavior between β ‐CD and PPA, resulting in redshift phosphorescence emission from PPA stacking. Additionally, with the incorporation of Rhodamine B (RhB) or Sulforhodamine 101 (SR101) into the supramolecular film, color‐tunable phosphorescence from blue to white, yellow, and red relying on the thermal stimulation is realized through triplet‐to‐singlet Förster resonance energy transfer (TS‐FRET) platform. These thermochromic phosphorescence materials are successfully applied in multilevel anticounterfeiting and information encryption, which provides a new simple approach for temperature‐responsive TS‐FRET multicolor luminescence supramolecular materials.