Colour tunable photoluminescence studies of Dy³⁺/Eu³⁺ co-doped BaPbAlFB glasses for epoxy-free w-LED applications

Barium lead alumino fluoroborate (BaPbAlFB) glasses singly and co-doped with Dy³⁺ and Eu³⁺ ions were prepared by melt quench method and studied their photoluminescence (PL) properties along with energy migration. Singly doped Dy³⁺/Eu³⁺ ions in BaPbAlFB glasses under 365 and 393 nm excitation wavelengths emit the PL bands through Dy: (⁴F_9/2 → ⁶H_15/2 and ⁴F_9/2 → ⁶H_13/2) and Eu: (⁵D₀→⁷F₂) transitions located at (Dy: 483 and 575 nm) and (Eu: 613 nm) respectively. Further, tunability of PL emissions is achieved by exciting the Dy³⁺/Eu³⁺ co-doped BaPbAlFB glasses at various wavelengths. The obtained CIE (0.34, 0.33) and CCT value (5080.4 K) of Dy³⁺/Eu³⁺ co-doped BaPbAlFB glass produced white light emission under 365 nm excitation wavelength. The corresponding CCT values of Dy³⁺/Eu³⁺ co-doped BaPbAlFB glasses varied from 1580 to 5080 K and their corresponding color emission changes from intense red to white light regime quite suitable for fabrication of epoxy-free w-LED devices.