DOI: 10.5061/dryad.vq83bk3v3
title: Photoluminescence processes in τ-phase Dy3+/Tb3+-codoped Ba1.3Ca0.7SiO4 phosphors for solid-state lighting

description: The τ-phase-Ba1.3Ca0.7SiO4 phosphors co-doped with 3 mol% Dy3+ and ~1-5
 mol% Tb3+ 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 Dy3+/Tb3+ co-doped Ba1.3Ca0.7SiO4 phosphors was explored by using the
 photoluminescence excitation, emission, and decay curves. Importantly, the
 photonic energy transfer from (Dy3+: 4F9/2 + Tb3+: 7F6) to (Dy3+: 6H15/2 +
 Tb3+:5D4) was observed, in which the Dy3+ ions acts as a light-emitting
 donor whereas the Tb3+ ions as a light-absorbing acceptor, resulting in an
 enhanced emission from the co-doped Ba1.3Ca0.7SiO4: Dy3+/Tb3+ 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 Tb3+ concentrations under ultraviolet
 light.
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.
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.