Octahedral modulation of W⁶⁺/Mo⁶⁺ in Ba₂MgTeO₆ for smart lighting and anti-counterfeiting

Oxide-based double perovskites have emerged as a potential alternative for multifunctional phosphors. In this work, the multifunctionality of W⁶⁺/Mo⁶⁺ substituted Ba₂MgTeO₆ double perovskites was investigated in detail. W⁶⁺ substitution produces diverse emissions in the blue (410 nm) and green (514 nm) regions due to the charge transfer transitions within the regular and irregular WO₆ octahedra, whereas Mo⁶⁺ substitution generates green emission (519 nm), which originates from the charge transfer transition within MoO₆ octahedra. Both W⁶⁺ and Mo⁶⁺ incorporated double perovskites exhibit extraordinary photoluminescence performance with a higher quantum yield of 47.3% and 40.7%, respectively. Temperature-dependent PL studies ensure better thermal stability for all the synthesized phosphors. Moreover, the Ba₂MgTeO₆:0.10W⁶⁺ phosphor was employed on a 310 nm UV chip to demonstrate its applicability in fabricating bluish white pc-LEDs. Furthermore, a detailed investigation on the Ba₂MgTeO₆:0.01Mo⁶⁺ based phosphor for the development of fluorescence-based latent fingerprint detection was carried out. The study ensures high selectivity, superior sensitivity, low background interference, and better applicability for the phosphor in LFP detection. Finally, anti-counterfeiting ink was prepared by using Ba₂MgTeO₆:0.01Mo⁶⁺ and is effectively applied onto different surfaces, including a simulated bank note, which confirms its practicability in safeguarding confidential documents. This research points out that the as-developed W⁶⁺/Mo⁶⁺ activated double perovskites can be appropriately used in multifunctional phosphor applications with the aid of UV chips or hand-held UV lamps and have exceptional potential in pc-LEDs, fingerprint recognition, data encryption, and anti-counterfeiting.