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

•A series of Dy3+-doped tellurate NaMgLaTeO6 phosphors were prepared by a solid-state reaction.•The band gap (Eg) of the direct semiconductor NaMgLaTeO6 is calculated initiatively.•The luminescence properties of the novel yellow-emitting phosphor (NaMgLaTeO6:Dy3+) for w-LEDs were investigated for the first time.•The phosphor exhibits high thermal stability (luminescence intensity remains 85.0 % at 480 K). The novel Dy3+-doped NaMgLaTeO6 (NaMgLaTeO6:Dy3+) 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 (P21/m (11)) and features the double perovskite structure. The band gap (Eg) of the direct semiconductor NaMgLaTeO6 is calculated to be 2.065 eV. Under 388 nm excitation, the 4F9/2→6H13/2 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 (Ea = 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 NaMgLaTeO6:Dy3+ can be clearly reflected on different surfaces. In summary, NaMgLaTeO6:Dy3+ phosphor has proven high potential in w-LEDs production and LFP detection. [Display omitted]