Study on the properties of Sm3+-Doped CaTbAl3O7 phosphors

New single phase and adjustable emission phosphors have attracted a lot of attention because of the good luminous properties. In this work, Sm 3+ doped CaTbAl 3 O 7 phosphors are prepared in air by solid-state method. The crystal structure, concentration dependent spectra, lifetimes, and luminescence properties are investigated. Because of the 4 f 8 → 4 f 7 5 d 1 and 4 f → 4 f transitions of Tb 3+ ion, host (CaTbAl 3 O 7 ) shows an excitation spectrum in the range of 220–520 nm under monitored at 544 nm and emits yellow-green light under excitation 248, 284, and 368 nm due to the 5 D 4 → 7 F J ( J  = 0, 1, 2, 3, 4, 5, and 6) transitions of Tb 3+ ion. CaTbAl 3 O 7 :Sm 3+ under monitored 598 nm contains the excitation spectral peaks of both CaTbAl 3 O 7 and Sm 3+ ion. With excitation at 368 nm, CaTbAl 3 O 7 :Sm 3+ glows orange-red light, its PL spectrum has both host (CaTbAl 3 O 7 ) and Sm 3+ ion contributing, and the chromaticity coordinates are about (0.5499, 0.4351). Under excitation 402 nm, the red-orange emission of CaTbAl 3 O 7 :Sm 3+ is only the contribution of Sm 3+ ion and the chromaticity coordinates are about (0.5823, 0.4168). The energy transfer process from Tb 3+ in host (CaTbAl 3 O 7 ) to Sm 3+ ions can be confirmed via the spectral properties. We explain the luminous mechanism of CaTbAl 3 O 7 :Sm 3+ by the energy level diagrams of Tb 3+ and Sm 3+ .