Structural and tunable optical properties of LiMgPO 4 :Tb 3+ phosphor fabricated by sol–gel method

• Published in: International journal of applied ceramic technology 2024-05, Vol.21 (3), p.2482-2497
• Main Author: Katı, Mehmet İsmail
• Format: Article
• Language: English
• ISSN: 1546-542X; 1744-7402
• DOI: 10.1111/ijac.14653

In the study, Tb 3+ ‐doped LiMgPO 4 phosphors between .10 and 5 mol% were successfully synthesized by the sol–gel process. The crystal structure of Tb 3+ ‐doped LiMgPO 4 was identified by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and X‐ray photoelectron spectroscopy (XPS) analyses. The XRD results for LiMgPO 4 ceramics doped with Tb 3+ indicated a single‐phase up to 5 mol%, accompanied by lattice shrinkage. An SEM analysis of LiMgPO 4 samples showed that increasing Tb 3+ concentration reduced grain size but did not cause any significant change in slightly angular and round grains. The emission intensity of phosphor increased from .10 to 5 mol%, and no concentration quenching was observed. The luminescence color of LiMgPO 4 :Tb 3+ phosphor can be tuned from blue to green through cross‐relaxation with the increase in Tb 3+ concentration. The photoluminescence emissions of LiMgPO 4 :Tb 3+ on the CIE diagram shifted from blue to green as the Tb 3+ concentration increased. The color purity of the 5 mol% Tb 3+ ‐doped phosphor showing the strongest emission was measured at 22.71%, whereas the color‐correlated temperature parameter was found to be 5573 K. The phosphors exhibited bi‐exponential decay profiles, and the observed lifetimes of 5 D 3 decreased with the increase of Tb 3+ , where the cross‐relaxation effect increased. The quantum efficiency ( ɳ QE ) of the phosphor was determined using the cross‐relaxation process. For Tb 3+ concentrations ranging from .1 to 5 mol%, the ɳ QE of the 5 D 3 state decreased from 62.49% to 28.29%. The research may offer a new perspective and new approaches for tuning luminescence in Tb 3+ ‐doped phosphors.