Luminescence peculiarities of Eu3+ ions in multicomponent Ca2YSc2GaSi2O12 garnet

Novel multicomponent garnet phosphors, Ca2Y1-xEuxSc2GaSi2O12 (x = 0, 0.05, 0.1, 0.25 and 0.5), have been synthesized by a high-temperature solid-state reaction method using the precursors obtained under hydrothermal conditions. Their structures, morphology and vibronic properties have been studied by XRD, SEM methods and Raman spectroscopy. It has been found that ceramic phosphor pellets consist of microcrystals having a narrow size distribution and a mean size of 1 μm with a maximum phonon energy of 864 cm−1 for the crystal lattice of these compositions. Under UV and blue excitation, Eu3+:Ca2YSc2GaSi2O12 phosphors exhibit red f-f luminescence of Eu3+ ions at the distorted D2 site of the garnet structure and broadband blue and red emissions centered at ∼417 nm, 600 nm and 770 nm as ascribed to the defects of the garnet host. The quantum yield of luminescence reaches 26% for Ca2Y0.75Eu0.25Sc2GaSi2O12. The spectroscopic properties of Eu3+ ions have been characterized with the Judd-Ofelt (J-O) theory and luminescence decay studies. The J-O parameters are Ω2 = 2.212, Ω4 = 2.888, and Ω6 = 2.259 [10−20 сm2] and the luminescence quantum efficiency for Eu3+ ions ηq is 83% in Ca2Y0.95Eu0.05Sc2GaSi2O12. The developed materials are promising as color-tunable phosphors.