Photoluminescence studies on dysprosium doped glass ceramics containing α-Na₃AlF₆ crystalline phase for white light emission

The present work focuses on Dy³⁺ doped 20SiO₂-(20-x) B₂O₃–10Al₂O₃–10ZnO–30NaF–10ZnF₂ glass ceramics (GCs), a white light emitting material prepared by conventional melt-quenching technique and thermal treatment. The glass ceramics exhibited good morphological evolution of α-Na₃AlF₆ crystals at elevated temperatures. Bandgap values are obtained lower for glass ceramics compared to precursor glass which almost tends to come closer to the bandgap value of semiconductor. A good photoluminescence (PL) performance is monitored in glass ceramics with increased emission intensity having two dominant peaks at 482 and 575 nm. Stimulated emission cross section in glass ceramics obtained higher for the level ⁶H_13/2 characterize their significance in laser active media. Quantum efficiency is achieved greater than 80% for glass ceramics ensures their appropriateness for LEDs application. In particular, the yellow to blue intensity, colour coordinates and colour correlated temperature have been evaluated for glass ceramics. With the formation of α-Na₃AlF₆ crystalline phase surrounded by Dy³⁺ ions, the PL properties in glass ceramics is enhanced notably. The obtained glass ceramics should be acknowledged as a promising material in white-LEDs and optoelectronic devices applications.