Structure and photoluminescence of Eu3+ doped Sr2InTaO6 red phosphor with high color purity.

ABSTRACT

The Eu3+-doped Sr2InTaO6 phosphors were obtained by solid-state reaction method and the phase purity of Sr2InTaO6Eu3+ samples were investigated by the XRD patterns. The Rietveld refinements were conducted to further obtain crystal structure information and the results indicate Sr2InTaO6Eu3+ samples crystallized in the monoclinic system with a P 121 space group. The optical band gap of Sr2InTaO6 was calculated to be 3.84 eV by the diffuse reflectance spectra, which are consistent with the result (3.823 eV) of density functional theory. Under 396 nm excitation, the Sr2InTaO6Eu3+ phosphor showed a red photoluminescence band centered at about 624 nm due to the 5D0 → 7F2 transition. Monitored at 624 nm, the phosphors showed two wide bands from 200 nm to 500 nm, which originated from the charge-transfer band of Eu3+-O2- and f-f transitions of Eu3+ ions. The optimum luminous concentration is 0.12 because of the concentration quenching determined to be a quadrupole-quadrupole interaction. The luminescence decay lifetimes of the Sr2InTaO6Eu3+ phosphors were milliseconds. Significantly, the temperature-dependent emission spectra of Sr2InTaO60.12Eu3+ phosphors exhibited good thermal stability and the CIE chromaticity coordinates of Sr2InTaO60.12Eu3+ were (0.6265, 0.3693) with high color purity. The present work demonstrated that the Sr2InTaO6Eu3+ red-emitting phosphors show great application in lighting technology.