Preparation and Spectral Properties of Mg[Al.sub.2][O.sub.4]: [Tb.sup.3+] Phosphor

A series of [Tb.sup.3+] doped cubic Mg[Al.sub.2][O.sub.4] green phosphors were synthesized via hydrothermal method followed by a post-annealing process. The variation regularity of phase structure, morphology, particle size and concentration quenching mechanism were investigated. The results showed that the crystal structure of matrix materials was not affected when [Tb.sup.3+] ions were introduced. In addition, the micrometer-sized rods and excellent dispersion of the particles were obtained by adding urea. Under excitation at 377 nm, the phosphors exhibited the characteristic of [Tb.sup.3+] emissions with the peaks located at 488 nm ([.sup.5][D.sub.4] [right arrow] [.sup.7][F.sub.6]), 544 nm ([.sup.5][D.sub.4] [right arrow] [.sup.7][F.sub.5]) and 588 nm ([.sup.5][D.sub.4] [right arrow] [.sup.7][F.sub.4]), respectively. Moreover, based on optical analysis, it can be inferred that electric dipole-dipole (d-d) interaction plays an important role in concentration quenching process of [Tb.sup.3+] ions. The green light emitting phosphor Mg[Al.sub.2][O.sub.4]: [Tb.sup.3+] can be realized by adjusting the concentrations of [Tb.sup.3+], and the optimum concentration of [Tb.sup.3+] ions in Mg[Al.sub.2][O.sub.4] was found to be 0.02. Finally, the average fluorescence decay lifetime and the CIE chromaticity coordinates of [Mg.sub.0.98][Al.sub.2][O.sub.4]:0.02[Tb.sup.3+] phosphor were calculated to be 1.2005 ms and (0.3197 0.4109), respectively. The above results suggest that the developed phosphor could have potential to be used as a single-phase green emission phosphor for near-ultraviolet light-emitting diode (NUV-LED) applications.
Aluminate-based luminescent materials activated by rare earth ions are of interest due to their good water resistance, stable chemical properties, high efficiency, and lower cost (1-3). As the use of [...]