| Abstract [eng] |
Efficient and thermally stable phosphors are essential for solid-state lighting, bioimaging, and optical sensing applications. The aim of this study is to investigate the luminescence properties of Na1–xAlGe1–0.5xGeO4-based phosphors doped with trivalent Bi3+, Dy3+, Eu3+, Pr3+, Sm3+, and Tb3+ ions. Doping concentrations ranged from 0.1–8 mol%, depending on the ion. Phosphors were synthesised via high-temperature solid-state reaction at 1000 °C for 4 hours and characterised using X-ray diffraction, photoluminescence spectroscopy, luminescence decay analysis, and quantum yield measurements. XRD analysis showed that samples with dopant ion concentrations of up to 1 % are single-phase, but higher concentrations lead to the appearance of impurity phase peaks, which become stronger with increasing concentrations. The emission spectra revealed distinct luminescent properties for each dopant. Bi3+-doped samples emitted a strong blue light at 420 nm, while Dy3+-doped samples showed yellow emission at 574 nm. Eu3+, Pr3+, and Sm3+-doped samples exhibited red and orange-red emissions at 611 nm, 612 nm, and 600 nm, respectively, whereas Tb3+-doped samples emitted a prominent green light at 549 nm. In terms of optical performance, Bi3+-doped samples achieved a maximum quantum yield of 5.80%. Dy3+-doped samples exhibited a peak quantum yield of 3.94% and a longest decay time of 538.19 μs. Eu3+-doped samples showed the highest quantum yield of 14.27% and a maximum decay time of 1589.42 μs. Sm3+-doped samples reached a quantum yield of 3.61% with a decay time of 1896.76 μs. Tb3+-doped samples demonstrated the longest decay time overall, reaching 2342 μs. |
