Spectroscopy properties of novel red-emitting Sm: Ca2LiScB4O10 phosphor-in-glass for WLED device

Abstract

In this paper, a novel red-emission Ca2LiScB4O10: Sm phosphor and the phosphor-in-glass system was synthesized by a high-temperature solid-state reaction and melt-quenching methods. 50–100 nm well-distributed monoclinic Ca2LiScB4O10: Sm phosphors with space group of P21/n were confirmed through Transmission electron microscopy and SAED patterns. Rietveld refinement XRD pattern verified that the doping of different amounts of Sm3+ ions decreased the lattice constants/volume and shifted the diffraction peaks. The Fourier transform infrared spectra, nuclear magnetic resonance, and X-ray photoelectron spectroscopy revealed the change of vibrational modes and coordination groups in the Ca2LiScB4O10 and boro-phosphate host as the Sm3+ amounts increased. The band gap calculated using Tauc's plot showed that the band gap decreased from 3.86 to 3.6 eV for phosphors and from 3.75 to 3.0 eV for phosphor-in-glasses when the Sm3+ concentration increased from 0.1% to 1%, and agree well with DFT simulation values. The density of states analysis suggests that most of Sm3+ occupied the Ca2+ sites while partial Sm3+ replaced the Sc2+ sites. Radiative parameters such as cross-section and branching ratio were explained in terms of the Judd-Ofelt parameter. 0.9%CLSBO phosphor-doped glass exhibited the strongest red emission with high color purity (94.4%), long lifetime (2.365 ms), and good thermal stability (91%) in the 25–250 °C temperature range.