Synthesis and luminescent study of Ce3+-doped terbium–yttrium aluminum garnet

Terbium–yttrium aluminum garnets (TYAG) doped with Ce3+ ions have been prepared by solid state reactions between nanostructured oxides of aluminum and rare earths. The luminescent properties of Ce3+ ions in (Тb0.8Y0.2)3(1−x)Ce3xAl5O12 (х = 0.03) have been studied upon excitation in the 2–20 eV region. The substitution of Tb3+ for Y3+ in the garnet structure results in broadening the emission band and shifting its maximum towards the longer wavelengths. It was found that in addition to the 4fn → 4fn−15d excitation bands of Ce3+ and Tb3+ ions, the excitation spectra for the Ce3+ emission contain broad bands at 6.73 and ∼9.5 eV. These bands are attributed to the Ce3+-bound exciton formation and O 2p → Al 3s, 3p transitions, respectively. In contrast to the predictions based on the results of electronic structure calculations on Y3Al5O12 and Tb4Al2O9, the threshold of interband transitions in TYAG is at high energies (⩾7.3 eV), and contributions from Altetr and Aloct atoms to the conduction-band density of states are evaluated as quite essential.

► Ce3+-doped garnets (TYAG) were prepared using nanostructured reagents.
► The Ce3+ ions cause a very efficient yellow emission of the samples.
► The reasons for the long wavelength position of this emission are discussed.
► Contribution from Al atoms to the conduction band of TYAG is quite essential.