Anti-counterfeiting and multifunctional applications of near white emitting La1.99MgTiO6:0.01Dy perovskite nano phosphors

Abstract

A 1 wt% dysprosium doped double perovskite nano phosphor La2MgTiO6 is synthesised by a low-temperature combustion method. When excited with UV radiation (351 nm), the sample shows major characteristic emission peaks at 480 nm (4F9/2 →6H15/2) and 574 nm (4F9/2 →6H13/2) whereas, when excited by IR radiation (980 nm), an up-conversion emission peak at 654 nm (4F9/2 →6H11/2) is observed. The photoluminescence spectra of La1.99Dy0.01MgTiO6 show dominant blue emission, which obliges potential white LED applications with chroma coordinates (0.32, 0.33). On the other side, the samples annealed above 1223 K build suitable reading light that shows dominant yellow emission with a quantum efficiency of 69.25 %; which simplifies why samples with high-temperature heat treatment are pertinent yellow-emitting phosphor. Using the Tauc plot, an improvement of ΔEg= 14 meV is seen owing to annealing at 1223 K. The XRD, Raman, SEM, and TEM results signify the increase in crystallinity and crystallite size with annealing. Noticeably, the red emission upon up-conversion highlights the medical imaging purpose. The effective combination of up-down conversion emission can be successfully exploited for anti-counterfeiting applications; underlining the multifunctional application of a single perovskite nano phosphor for smart materials.