Synergistic Ce3+, Tb3+ activated LaCaAl3O7 phosphor: Bridging forensic science with advanced w-LEDs applications

Abstract

In this study, we introduce a novel Ce3+/Tb3+ co-activated LaCaAl3O7 (LCAO) green-emitting phosphor, prepared via a solution combustion route using Aloe Vera (A.V.) gel as fuel. Detailed photoluminescence (PL) analysis revealed intense green emission at 542 nm with high internal quantum efficiency (IQE) of 89.9 %, under 330 nm ultra-violet (UV) excitation. Energy transfer (ET) from Ce3+ to Tb3+ ions was optimized, achieving ideal doping concentrations of 7 mol % Ce3+ and 3 mol % Tb3+. We fabricated a prototype near-UV (n-UV)-pumped white-LED (w-LED) device using LCAO:7%Ce3+,3%Tb3+ phosphor as a color converter. Operating at a 120 mA current, the LED emitted bright cool-white light with outstanding CIE chromaticity coordinates (0.3245, 0.3322), a high colour correlated temperature CCT of 5879 K, and an ultra-high color rendering index (CRI) of Ra = 95. Additionally, it demonstrated a luminous efficacy (LE) of 28.65 lm·W⁻1. The phosphor also exhibited remarkable thermal stability and resistance to color shift from 300 to 480 K, indicating suitability for high-performance lighting. Moreover, the optimized phosphor showed great potential for high-resolution latent fingerprint (LFP) detection. This work provides a promising approach for designing efficient LED phosphors, contributing to advanced solid-state lighting and forensic applications. Our findings establish LCAO:7%Ce3+,3%Tb3+ as a versatile material with significant implications for high-quality lighting and security technologies.