Engineered ultra-luminous La/YPO4:Eu3+ nanophosphors for advanced security ink and latent fingerprint (LFPs) detection

Designing versatile NPs for multifarious applications is crucial for achieving an array of criterion in realm, including improving efficiency, inexpensiveness, flexibility, least power consumption, etc. Facile hydrothermal treatment of La/YPO ₄:Eu ³⁺ NPs yields composite phase growth signifying even-sized NPs with the requisite elemental composition. Relative CTB predominates in LaPO ₄:Eu ³⁺; while luminescence of YPO ₄:Eu ³⁺ is notably higher when stimulated by atomic lines. Nevertheless, La/YPO ₄:Eu ³⁺ NPs exhibit adequate luminescence under both CTB and 394 nm ( ⁷F ₀→ ⁵L ₆) excitations, evincing intrinsic QY (63.91 %) with relatively large lifetime (∼ 6 ms) of ⁵D ₀ states, substantiated by J-O analysis. Designed NPs is readily cling to friction ridge skin residues demonstrating the efficient LFPs development through the ‘powder dusting approach’ on various substrate. NPs conjugated PVC gold medium and aqueous PVA were effectively used for security encryptions using the screen-printing technique. Reddish-orange emission with different excitation probabilities resulting in high QY emphasizes them in a class of futuristic versatile materials with potential applications in security ink, LFP development, LEDs, and display devices.