Carbon Dots-in-EuAPO-5 Zeolite: Triple-Emission for Multilevel Luminescence Anti-Counterfeiting

Abstract

Multilevel luminescence materials have aroused wide attention for their advanced anti-counterfeiting abilities. However, various complicated stimuli factors involved in multilevel luminescence anti-counterfeiting (MlLA) limit the practical applications of such materials. Herein, carbon dots (CDs) are in situ introduced into Eu-substituted AlPO₄ -5 zeolite (named CDs@EuAPO-5) via a solvent-free thermal crystallization method, which exhibits triple emissions including pink fluorescence mainly associated with Eu³⁺ in the zeolite framework, blue fluorescence and green room temperature phosphorescence (RTP) associated with CDs. CDs are uniformly embedded in the EuAPO-5 zeolite matrix. Such composite displays excellent photo-, thermo-, and solvent resistance, as well as long-term storage-stability. Moreover, the triple emissions of the composite only need two kinds of common excitation lights to trigger, without involving other complicated stimuli. A triple-level luminescence anti-counterfeiting (TlLA) label has been built, realizing facile, quick, and advanced luminescence anti-counterfeiting that is hard to copy.

Keywords: carbon dots; luminescence; multilevel anti-counterfeiting; rare earth ions; room temperature phosphorescence; zeolites.