Effects of Ce3+/Sm3+ co-doping as a luminescent modifier in borotellurite glasses for solid-state lighting

In this work, Ce³⁺ (0.5 mol%) and Sm³⁺ (0.5, 1.0, 1.5 and 2.0 mol%) co-doped borotellurite (BTZN) were successfully fabricated by the melt quenching method. Crystal structure and luminescent characteristics of the synthesized glasses are investigated in detail through X-ray diffraction, SEM images, absorption, excitation, emission spectra and luminescence decay. Result of the XRD patterns shows the amorphous phase nature of the BTZN glass sample. SEM images indicated that surface morphologies of glass samples are highly homogeneous. The analysis of photoluminescence reveals a notable spectral overlap between the Ce³⁺ emission and the Sm³⁺ excitation in the means of effective energy transfer (ET): Ce³⁺ → Sm³⁺, thus achieving better luminescence properties of Sm³⁺. The luminescence lifetime of BTZN:Ce/Sm glasses was found to decline on rising Sm³⁺ concentration, which strongly determine in increasing the ET efficiency by dipole-quadrupole interaction. For the co-doping glasses, the CIE coordinates of the selected glasses can be adjusted from blue to bluish-white colors regions with varying the Sm³⁺ concentration.