Low-temperature in situ preparation of Eu 3+ /Tb 3+ -doped CaMoO 4 /SrMoO 4 nanoparticle thin films and their application in anti-counterfeiting.

Rare earth-doped metal oxide thin films exhibit remarkable potential for application in anti-counterfeiting, owing to their exceptional fluorescent properties. However, the existing fabrication techniques for these rare earth-doped luminescent thin films are predominantly complex and necessitate high-temperature conditions. In light of this issue, we present a low-temperature method for in situ fabrication of luminescent Ca 1- x MoO 4 :Eu x 3+ and Sr 1- x MoO 4 :Tb x 3+ nanocrystal thin films by a solution deposition process. The developed method has the advantages of simple operation, rapid and low-temperature synthesis. The optimal chemical compositions of molybdate-based luminescent films are Ca 0.90 MoO 4 :Eu 0.10 3+ and Sr 0.90 MoO 4 :Tb 0.10 3+ . Moreover, we evaluate the practical feasibility of luminescent nanoparticle films in the field of anti-counterfeiting by combining the unique fluorescent properties of rare earth ions and designing customized fluorescent patterns.