Thermal stable NaMgLaTeO6:Dy3+ double perovskite yellow phosphors for w-LEDs and latent fingerprint visualization

The novel Dy 3+ -doped NaMgLaTeO 6 (NaMgLaTeO 6 :Dy 3+ ) phosphors were produced through a high-temperature solid-state reaction. X-ray diffraction (XRD) analysis and Rietveld refinement manifest that the pure phosphor was committed to the space group (P2 1/m (11)) and features the double perovskite structure. The band gap ( E g ) of the direct semiconductor NaMgLaTeO 6 is calculated to be 2.065 eV. Under 388 nm excitation, the 4 F 9/2 → 6 H 13/2 energy level transition contributes to the maximum emission peak at 572 nm. Other properties of the phosphor include optimal concentration ( x = 5 mol %), high thermal stability, activation energy ( E a = 0.31 eV), and internal quantum efficiency (IQE = 31.44 %). The relevant color coordinate of the white light emitting diode (w-LED) prepared by the phosphor is (0.298, 0.311). The features of the latent fingerprint (LFP) created by NaMgLaTeO 6 :Dy 3+ can be clearly reflected on different surfaces. In summary, NaMgLaTeO 6 :Dy 3+ phosphor has proven high potential in w-LEDs production and LFP detection.