Luminous thermal stability and versatile applications of red emitting Ba3Y4O9: Eu3+ phosphor in W-LEDs, forensic science and security technologies

Abstract

A red-emitting Ba₃Y₄O₉: Eu³⁺ (BYO: Eu³⁺) phosphors are synthesized via cost effective solution combustion method. The phase structure of the synthesized phosphor is analyzed through X-ray diffraction (XRD) with Rietveld refinement, complemented by field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS). Photoluminescence (PL) studies of BYO: 3Eu³⁺ revealed strong orange-red emission peaks centered at 586 nm and 614 nm under 392 nm deep ultraviolet excitation. The optimal doping concentration is determined to be 3 mol%, beyond which concentration quenching is observed. The BYO: 3Eu³⁺ phosphor exhibited remarkable thermal stability, maintaining 85 % of its luminescence intensity at 420 K, with an activation energy (E_a) of 0.375 eV. The quantum efficiency is assessed using an integrating sphere, yielding an internal quantum efficiency (I_QE) of 91.3 %. The fabricated white light emitting diode (w-LED) achieved a correlated color temperature (CCT) of 4952 K, an impressive color rendering index (CRI) of 92, and Commission Internationale de l’Éclairage (CIE) chromaticity coordinates of (0.346, 0.348). Additionally, BYO: 3Eu³⁺ demonstrated effective visualization of level I–III LFP structures under ultraviolet illumination, facilitating forensic detection in various real-world applications. These findings underscore the significant potential of BYO: 3Eu³⁺ phosphors for w-LEDs lighting, forensic fingerprint analysis, and anticounterfeiting technologies.