Photoluminescence processes in τ-phase Ba1.3Ca0.7- x- y SiO4: x D y 3+/ y Tb3+ phosphors for solid-state lighting

Desta R Golja; Menberu M Woldemariam; Francis B Dejene; Jung Yong Kim

doi:10.1098/rsos.220101

Photoluminescence processes in τ-phase Ba_1.3Ca_{0.7- x- y} SiO₄: x D y ³⁺/ y Tb³⁺ phosphors for solid-state lighting

R Soc Open Sci. 2022 Jun 15;9(6):220101. doi: 10.1098/rsos.220101. eCollection 2022 Jun.

Authors

Desta R Golja^{1

2}, Menberu M Woldemariam³, Francis B Dejene⁴, Jung Yong Kim^{5

6}

Affiliations

¹ Department of Materials Science and Engineering, Jimma Institute of Technology, Jimma University, P.O. Box 378, Jimma, Ethiopia.
² Department of Physics, University of the Free State (QwaQwa Campus), P.O. Box 339, Bloemfontein, South Africa.
³ Department of Physics, Jimma University, P.O. Box 378, Jimma, Ethiopia.
⁴ Department of Chemical and Physical Sciences, Walter Sisulu University (Mthatha Campus), Private Bag XI UNITRA 5117, South Africa.
⁵ Department of Materials Science and Engineering, Adama Science and Technology University, P.O. Box 1888, Adama, Ethiopia.
⁶ Center of Advanced Materials Science and Engineering, Adama Science and Technology University, P.O. Box 1888, Adama, Ethiopia.

Abstract

The τ-phase Ba_1.3Ca_0.7-x-y SiO₄:xDy ³⁺/yTb³⁺ phosphors co-doped with Dy ³⁺ (x = 0.03) and Tb³⁺ (y = 0.01-0.05) trivalent rare-earth ions were prepared by the gel-combustion method. The structure-property relation of the samples was examined by X-ray diffraction, scanning electron microscopy and spectrophotometer. Here, the effect of Tb³⁺'s concentration on the spectroscopic properties of Ba_1.3Ca_0.7-x-y SiO₄:xDy ³⁺/yTb³⁺ phosphors was explored by using the photoluminescence excitation, emission and decay curves. Importantly, the photonic energy transfer from (Dy ³⁺:⁴F_9/2 + Tb³⁺:⁷F₆) to (Dy ³⁺:⁶H_15/2 + Tb³⁺:⁵D₄) was observed, in which the Dy ³⁺ ions act as a light-emitting donor whereas the Tb³⁺ ions as a light-absorbing acceptor, resulting in an enhanced emission from the co-doped Ba_1.3Ca_0.7-x-y SiO₄:xDy ³⁺/yTb³⁺ (x = 0.03 and y = 0.01-0.05) phosphors. Finally, the chromaticity coordinates were determined from the measured emission spectra, locating at the green and white light regions. This observation indicates that the characteristic emission colour could be tuned from white to green by varying Tb³⁺ concentrations under ultraviolet light.

Keywords: light-emitting diode; phosphors; photoluminescence; rare-earth ion; silicate; structure–property relation.

Associated data

Dryad/10.5061/dryad.vq83bk3v3