Multicolor luminescence and triple-mode emission of simple CaTiO3:Pr3+,Er3+particles for advanced anti-counterfeiting

Lanthanide-based luminescent anticounterfeiting materials are widely used in various kinds of products. At present, the conventional lanthanide-based luminescent anticounterfeiting technique is based on photoluminescence from ultraviolet light irradiation, resulting in the decreased efficiency of anticounterfeiting applications. In this work, we realized three luminescence modes in a perovskite structure (CaTiO3:Pr3+,Er3+), in which the excitation-wavelength-dependent photoluminescence (PL) emission, afterglow and upconversion luminescence (UCL) of a doped lanthanide were first presented. Upon ultraviolet excitation, the color of the PL emission can be finely tuned from red to orange, yellow and green by increasing the excitation wavelength from 365 nm to 380 nm. The doped lanthanide emits an intense green color upon illumination with a 980 nm excitation source and a long persisting red color (612 nm) when a UV lamp at 365 nm excitation is switched off. Based on the above luminescence modes of CaTiO3:Pr3+,Er3+, a multilevel anticounterfeiting quick response code (QR code) was developed. The QR code readily integrates the advantages of the excitation wavelength-dependent PL emissions, a strong red afterglow and sensitive excitation power-dependent UCL emissions in one overall device. The presented multilevel anticounterfeiting strategies may inspire the resolution of counterfeit issues in various fields.