On the luminescent properties of Eu3+ doped La2Hf3(WO4)9

This work concerns the host material La2Hf3(WO4)9 doped with Eu3+ as a widely applied red emitting activator, focusing on its luminescent properties under various excitation conditions. La2-xEuxHf3(WO4)9 solid solutions were synthesized and confirmed to crystallize in a single-phase structure. The reflectivity decreases with increasing Eu3 doping level, while characteristic Eu3 electronic transitions emerge, enhancing absorption strength and emission intensity. Emission spectra under various excitation conditions (395 nm; 160 nm; X-rays) reveal concentration-dependent characteristic Eu3 luminescence behavior with stable peak positions and red emission profiles. Under X-ray excitation, luminescence peaks at 10 % Eu3 doping, followed by intensity quenching at higher concentrations due to non-radiative mechanisms. The depth of X-ray penetration, calculated using the Feldman equation, correlates with the observed luminescence efficiency. The materials exhibit a rather low thermal quenching temperature, with T1/2 determined as 228 K. Lifetime measurements highlight concentration quenching effects and distinct Eu3 environments. Chromaticity coordinates confirm a consistent red emission with minor variations across doping levels. The study provides insights into the structural, optical, and thermal properties of Eu3 -doped LaaHfs(WOa)s, emphasizing its potential and limitations for luminescent applications.