Consequences of ET and MMCT on Luminescence of Ce(3+)-, Eu(3+)-, and Tb(3+)-doped LiYSiO4.

Ce(3+), Eu(3+), and Tb(3+) singly doped, Ce(3+)-Tb(3+), Tb(3+)-Eu(3+), and Ce(3+)-Eu(3+) doubly doped, as well as Ce(3+)-Tb(3+)-Eu(3+) triply doped LiYSiO4 phosphors were prepared by a high-temperature solid-state reaction technique. Rietveld refinement was performed to determine the structure of host compound. The cross-relaxation (CR) of Tb(3+) is quantitatively analyzed with the Inokuti-Hirayama model of energy transfer (ET), and the site occupancy is confirmed by emission spectra of Eu(3+). ET and metal-metal charge transfer (MMCT) are systematically investigated in Ce(3+)-Tb(3+), Tb(3+)-Eu(3+), and Ce(3+)-Eu(3+) doubly doped systems. The combined effects of ET and MMCT on luminescence and emission color of Ce(3+)-Tb(3+)-Eu(3+) triply doped samples are discussed in detail, showing that the photoluminescence emission is tunable in a large color gamut.