Deciphering the role of multi-functional Mg2GeO4:Eu3+, Sm3+ nanophosphors as a luminescent armour against counterfeiting and implementing its practical adaptability

Abstract

The escalating threat of counterfeiting poses a significant challenge across the world. Hence, the development of robust anti-counterfeiting measures and their ease of practical implementation are in demand. In this view, the present work establishes the synthesis of Mg₂GeO₄:Eu³⁺ (7 mol %), Sm³⁺ (1–5 mol %) nanophosphors via a solution combustion route. The structural studies of the prepared samples confirmed the pure orthorhombic phase with Pnma space group. The photoluminescence emission spectrum monitored under 393 nm excitation wavelength displayed distinct, sharp peaks at ∼ 579, 589, 610, 659, and 707 nm. Further, the emission spectra showcase luminescence intensity enhancement upon co-doping, which is ascribed to efficient energy transfer between donor (Eu³⁺) and acceptor (Sm³⁺) ions. The quantum efficiency of the optimized nanophosphor reached an impressive 70.23 % and color purity of 95.9 %, which positioned the prepared nanophosphor as a promising candidate for white light-emitting diode applications. Moreover, various anti-counterfeiting patterns were designed, encrypted, and undergone rigorous environmental tolerance tests to assess their practical implications in real-world scenarios. The encrypted patterns exhibit high resistance to extreme temperatures and water, excellent chemicals and oil stability, battle against abrasions, and are exceptionally photo-stable. The obtained results affirm that the developed anti-counterfeiting patterns retained their integrity and functionality throughout the simulated environmental tests. This emphasizes the impending ability of the prepared Mg₂GeO₄:Eu³⁺ (7 mol %), Sm³⁺ (1–5 mol %) nanophosphors to combat counterfeiting.