Blue light emitting Sr2MgSi2O7:Eu2+ nanophosphor for latent fingerprint, anti-counterfeiting and near UV-LED applications

Eu2+ doped Sr2MgSi2O7 nanophosphors (SMSO:Eu2+ NPs) have been synthesized by using solid-state reaction method. As Eu2+ concentration increases, energy transfer (ET) between Eu2+ ions dominated attributed to dipole-dipole (d-d) interaction. Besides, temperature-dependent photoluminescence (PL) of optimized SMSO:7Eu2+ NPs is investigated. The emission shifts towards blue with increased temperature. From the temperature-dependent emission, the activation energy, is ∼0.40 eV. CIE coordinate is (0.1476, 0.1141) with CCT value of 3633 K. The optimized phosphor is used to detect LFPs on various surfaces. The level I-III features are clearly identified under UV 365 nm excitation. Several pores properties namely pore size, shape, number, position, type and pore inter-distance are analyzed in detail. The anti-counterfeiting results clearly showed the enhanced intensity owing to its nano-size, reduced light dispersion and increased light absorption. The overall results clearly suggest the optimized SMSO:7Eu2+ NPs are promising luminescent platform for nUV light-emitting diode (LED) and latent fingerprint (LFP) applications.