Preparation and Luminescent Properties of Tb3+-doped SrO–Al2O3–SiO2 Glass–Ceramics for white Light-Emitting Diode

Abstract

Tb³⁺-doped SrO–Al₂O₃–SiO₂ glass-ceramics are prepared by melting under ambient atmosphere and followed by two-step heat treatment approach. Extensive differential thermal analysis, X-ray diffraction and scanning electron microscope characterizations are applied to investigate thermal properties, crystal structure, and morphology of these glass-ceramics. The results indicate that the optimal ratio of two nucleation agents (TiO₂ and ZrO₂) is 3:1 (molar fraction) in glass-ceramics. In addition, several heat treatment schedules are developed to study the influence of treatment temperature on luminescence properties of Tb³⁺- doped glass-ceramics. The results demonstrate that there are four emission bands located at 489, 547, 588 and 623 nm under 376 nm ultraviolet excitation, corresponding to ⁵D₄ → ⁷F_j (j = 6, 5, 4, 3) transitions of Tb³⁺, respectively. At last, the corresponding chromaticity coordinates are calculated and constructed, which indicates that the Tb³⁺ glass-ceramic can emit approximate white light under 376 nm ultraviolet excitation when they nucleated at 950°C and crystallized at 1050°C. The white immersion approached standard illuminant C as the crystallization temperature increased.