Photoluminescence processes in τ-phase Dy3+/Tb3+-codoped Ba1.3Ca0.7SiO4 phosphors for solid-state lighting
Creators: name: Kim, Jung Yong
name: Golja, Desta R.
name: Woldemariam, Menberu M.
name: Dejene, Francis B.
Publisher: name: Zenodo
Year: 2022

description: The τ-phase-Ba<sub>1.3</sub>Ca<sub>0.7</sub>SiO<sub>4</sub> phosphors co-doped with 3 mol% Dy<sup>3+</sup> and ~1-5 mol% Tb<sup>3+</sup> 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 Tb<sup>3+</sup>'s concentration on the spectroscopic properties of Dy<sup>3+</sup>/Tb<sup>3+</sup> co-doped Ba<sub>1.3</sub>Ca<sub>0.7</sub>SiO<sub>4</sub> phosphors was explored by using the photoluminescence excitation, emission, and decay curves. Importantly, the photonic energy transfer from (Dy<sup>3+</sup>: <sup>4</sup>F9/2 + Tb<sup>3+</sup>: <sup>7</sup>F<sub>6</sub>) to (Dy<sup>3+</sup>: <sup>6</sup>H<sub>15/2</sub> + Tb<sup>3+</sup>:<sup>5</sup>D<sub>4</sub>) was observed, in which the Dy<sup>3+</sup> ions acts as a light-emitting donor whereas the Tb<sup>3+</sup> ions as a light-absorbing acceptor, resulting in an enhanced emission from the co-doped Ba<sub>1.3</sub>Ca<sub>0.7</sub>SiO<sub>4</sub>: Dy<sup>3+</sup>/Tb<sup>3+</sup> 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 color could be tuned from white to green by varying Tb<sup>3+</sup> concentrations under ultraviolet light.
description: &lt;XRD_Data&gt; Two columns: X-axis: 2theta (degree) and Y-axis: Intensity (a.u.) XRD_Dy3mol% Tb1mol%.csv (Dy 3 mol% and Tb 1 mol % doped phosphor sample XRD) XRD_Dy3mol% Tb2mol%.csv(Dy 3 mol% and Tb 2 mol % doped phosphor sample XRD) XRD_Dy3mol% Tb3mol%.csv (Dy 3 mol% and Tb 3 mol % doped phosphor sample XRD) XRD_Dy3mol% Tb4mol%.csv (Dy 3 mol% and Tb 4 mol % doped phosphor sample XRD) XRD_Dy3mol% Tb5mol%.csv (Dy 3 mol% and Tb 5 mol % doped phosphor sample XRD) &lt;PL_Data&gt; PL Data_Excitation and Emission Two columns: X-axis: Wavelength (nm) and Y-axis: Intensity (a.u.) PL Data_Emission Dy3+ 3mol% Tb3+ 1mol% PL Data_Emission Dy3+ 3mol% Tb3+ 2mol% PL Data_Emission Dy3+ 3mol% Tb3+ 3mol% PL Data_Emission Dy3+ 3mol% Tb3+ 4mol% PL Data_Emission Dy3+ 3mol% Tb3+ 5mol% PL Data_Excitation Dy3+ 1mol% Tb3+ 1mol% PL Data_Excitation Dy3+ 2mol% Tb3+ 2mol% PL Data_Excitation Dy3+ 3mol% Tb3+ 3mol% PL Data_Excitation Dy3+ 4mol% Tb3+ 4mol% PL Data_Excitation Dy3+ 5mol% Tb3+ 5mol% &lt;EDX data&gt; EDX data: Dy3+ 3 mol% and Tb3+ 1 mol % phosphor sample – EDX data EDX data: Dy3+ 3 mol% and Tb3+ 2 mol % phosphor sample – EDX data EDX data: Dy3+ 3 mol% and Tb3+ 3 mol % phosphor sample – EDX data &lt;SEM data&gt; Various SEM images as a function of composition and magnification. &lt;CIE color coordinate&gt; Example Calculated CIE color coordinates for emission in the co-doped Ba1.3Ca0.7SiO4:0.03Dy3+/xTb3+ (x=0.01-0.05) phosphors. Here, 3 mol% and 4 mol% Tb3+ doped phosphor showed almost overlapped data.Funding provided by: Jimma University<br>Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100005068<br>Award Number: JU/JIT/317103101-6417
description: X-ray diffraction (XRD) measurements (Model Philips Bruker D8 advance) were carried out to examine the structure and phase of the prepared phosphor materials. The scanning electron microscope (SEM) (Model JEOL JSM-7800F) was used to characterize the morphology of phosphors as a function of composition. Energy-dispersive X-ray spectroscope (EDX) (Oxford Aztee) was used to confirm the composition of elements in the Ba<sub>1.3</sub>Ca<sub>0.7</sub>SiO<sub>4</sub>: Dy<sup>3+</sup>/Tb<sup>3+</sup> samples. The PL emission and decay spectra were investigated using Cary Eclipse fluorescence spectrophotometer (Model LS-55) equipped with a xenon flash lamp to act as the excitation source.