Spectroscopic studies of Dy3+ doped borate glasses for cool white light generation

Highlights: • BAZN glasses with Dy³⁺ ions were prepared using melt quench technique. • Under n-UV excitation the BAZN glasses show white light emission. • Energy transfer through cross-relaxation leads to concentration quenching. • Calculated CIE coordinates are close to the commercial w-LED. • 0.5 mol% of Dy³⁺ in these glasses are apt for cool white light generation. - Abstract: The Dy³⁺ ions doped Na₂O-ZnO-Al₂O₃-B₂O₃ (BAZN) glasses with variable doping concentrations were synthesized by melt-quenching technique. The XRD pattern reveals amorphous nature of the as-synthesized glass. The FT-IR spectrum reveals various stretching and bending vibration of aluminates, borate and some other groups. The emission spectra exhibit two intense bands at around 482 nm (blue) and 575 nm (yellow) corresponding to the ⁴F_9/2 → ⁶H_15/2 and F_9/2 → ⁶H_13/2 transitions respectively. The CIE chromaticity coordinates of the as-synthesized glasses are lying in white region and in proximity to the coordinates for white light specified by National Television Standard Committee and commercial phosphor converted white light emitting devices. The decay profile of BAZN glasses showed bi-exponential behavior due to the energy transfer mechanism from excited donor ion to unexcited acceptor ion. The above-mentioned studies show potential of the as-synthesized Dy³⁺ doped BAZN glasses in solid state lighting applications.