Synthesis, structure and photoluminescence properties of Tm3+/Dy3+ co-doped borate glass for near-UV white LEDs

Abstract

Tm3+/Dy3+ single and co-doped SrO–MgO–B2O3 (SMB) glasses were fabricated via the conventional melt-quenching technique. The thermal stability of the host glass was determined by a differential scanning calorimetry (DSC) curve. X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy were measured to characterize the structural properties and vibration features of the as-prepared glasses, respectively. The transmittances of the studied glasses can reach about 90% in the range from 300 to 800 nm. It can be confirmed that Tm3+/Dy3+ single and co-doped SMB glasses can all be efficiently excited by near-ultraviolet (NUV) light through absorption and photoluminescence excitation spectra. Moreover, the emission spectra and fluorescence decay curves confirmed the existence of energy transfer between Tm3+ and Dy3+. The Tm3+/Dy3+ co-doped glasses can both realize tunable emission from blue light to cool white and eventually to warm white light under the excitation of 352, 362, and 365 nm. Furthermore, by using the Inokuti-Hirayama (I–H) model, the energy transfer is testified to be carried out in Tm3+-Dy3+ clusters through the dipole-dipole (d-d) interaction mechanism. More importantly, the thermal stability of Tm3+/Dy3+ co-doped SMB glass was demonstrated by temperature-dependent emission spectra. Overall, these results fully indicate that Tm3+/Dy3+ co-doped SMB glasses have great potential to be used in NUV-based white light-emitting diodes with different requirements.