Mesoporous silica-templated lanthanide-doped zinc gallogermanate nanophosphors with multicolour persistent luminescence for dual-mode anti-counterfeiting and data encryption

Persistent luminescent (PersL) nanoparticles have the inimitable ability to store and release energy over a sustained period, besides emitting light under excitation. This property makes them good candidates for developing next-generation anti-counterfeiting techniques. However, these nanomaterials suffer from a significant trade-off: improvements in the afterglow lifetime performance often come at the expense of size and morphological uniformity. Hence, we address this compromise by using mesoporous silica as the growth template to produce morphology-controlled zinc gallogermanate (ZGGO) PersL nanoparticles while improving the afterglow performance. Unlike typical ZGGO-based PersL systems that rely on utilizing Cr or Mn-based activators, we explored lanthanide-only doping (Eu 3 + , Dy 3+ ) systems to evaluate the role of rare-earth based dopants in changing the optical properties of the host lattice. The resulting PersL nanoparticles exhibit visually contrasting and distinct dual-mode emission signatures, with tuneable photoluminescence and PersL properties. The structural, morphological, and optical properties were characterized using X-ray diffraction, UV–Vis spectroscopy, and other techniques. Finally, incorporating these nanophosphors into coatings and paints, produce different visual patterns, thus enabling their usage in anti-counterfeiting and data encrypting applications. Hence these results establish mesoporous silica-based lanthanide-doped ZGGO PersL nanoparticles as promising materials for cost-effective dual-mode anti-counterfeiting and optical data encryption.