SrBiF: A New Bismuth-Based Host Material for Lanthanide Ions Doping: Synthesis, Downshifting, and Upconversion Luminescence Properties for Multimode Anticounterfeiting.

A new bismuth-based host material, i.e., SrBiF, is explored in this work. Undoped and lanthanide ion-doped SrBiF nanomaterials are prepared using a simple coprecipitation technique at 120 °C. The undoped nanomaterials exhibit a blue color under 365 nm excitation. The downshifting and upconversion photoluminescent properties of Er and Yb codoped SrBiF nanomaterials are investigated. The optimum up-conversion luminescence is produced by nanomaterials doped with 5% Yb and 0.2% Er. These nanomaterials show blue and magenta colors upon excitation at 365 and 395 nm wavelengths, respectively. SrBiF material doped with Er shows green emission, while the codoped Er, Yb nanomaterials exhibit an orange-red color under 980 nm light. A specific amount of polyvinyl chloride (PVC) is used for producing luminescent ink with these nanoparticles for multimode anticounterfeiting applications. The letters and patterns written with luminescent ink based on Er, Yb doped nanomaterials show blue, magenta, and orange-red colors under 365, 395, and 980 nm light, respectively. These results establish that this material can be effectively used as a multimode photoluminescent covert tag to combat counterfeiting.