Nitesh Kumar Manoharan, Samuel Paul David
Strong red-emitting cubic NaSrBiTeO 6:Eu 3+ double-perovskite phosphors with different Eu 3+ concentrations were synthesized using a solid-state diffusion method at 850 °C. Rietveld refinement of the XRD patterns confirmed that the incorporation of Eu 3+ did not modify the crystal structure framework. Characteristic vibrational modes were observed using FTIR and Raman spectroscopy, whereas SEM-EDX analysis revealed irregular microcrystals and a uniform distribution of dopants. An internal quantum efficiency (IQE) of 16.44% was achieved for 7% Eu 3+ -doped NaSrBiTeO 6 when excited at 465 nm. Temperature-dependent photoluminescence studies confirmed the excellent thermal stability of the phosphor, with 90% of its emission being retained even at 353 K. The temperature sensitivity parameters ( S a = 0.0466 K –1, S r = 0.4535%K –1 ) determined using the fluorescence intensity ratio highlight the suitability of the developed phosphors for optical thermometry. The phosphor’s color purity of 94.36% and correlated color temperature of 2174 K validate its suitability for warm pc-WLEDs. In addition to lighting, NaSrBiTeO 6:Eu 3+ powders exhibited superior performance in latent fingerprint detection when subjected to 365 nm UV illumination.