Synthesis and photoluminescence of high color purity red-emitting BaLaLiTeO6:Eu3+ phosphors ..

Red phosphors based on BaLaLiTeO6 doped with Eu3+ were prepared by high temperature solid state method. The XRD patterns for the representative samples revealed its single phase structure and the scanning electron microscopes were studied to reveal the morphology and homogeneous distribution of particles with different size. In addition, the density of states and partial density of states of each element revealed that Ba-O and La-O groups are the main factors that determine the optical properties of the BaLaLiTeO6. When emitted by 394 nm near-ultraviolet, all the samples emit bright red light near 618 nm because of 5D0 → 7F2 transition of Eu3+ ions. The optimal doping concentration of Eu3+ in BaLaLiTeO6 is 0.20 and the mechanism of concentration quenching is the dipole-quadrupole interaction. Besides, the temperature-dependent emission spectra of BaLaLiTeO6:0.2Eu3+ red sample were studied systematically and the thermal activation energy of the sample was 0.30 eV, indicating its good thermal stability. The lifetime of Eu3+ ions is in the millisecond level and the CIE chromaticity coordinate of BaLaLiTeO6:0.2Eu3+ is (0.6436, 0.3535) with a high color purity of 99.4%, which is close to the standard of red chromaticity. To sum up, the BaLaLiTeO6:Eu3+ phosphors are the hopeful red component applied in the white light illumination. [ABSTRACT FROM AUTHOR]