White emission from Dy3+ doped Gd2O3-B2O3 glass for WLEDs encapsulation

초록

Novel bell-shaped glasses were fabricated to study the electro-luminescence properties of the glasses for LED applications. The physical and optical properties of Dysprosium (Dy3+) doped Gd<inf>2</inf>O<inf>3</inf>-B<inf>2</inf>O<inf>3</inf> glasses were synthesised using the standard melt quenching procedure with compositions of 27.5Gd<inf>2</inf>O<inf>3</inf>-(72.5-x)B<inf>2</inf>O<inf>3</inf>-xDy<inf>2</inf>O<inf>3</inf> (where x = 0.05, 0.1, 0.5, 1.0, and 1.5 mol%). The highest emission intensity of Dy3+ doped Gd<inf>2</inf>O<inf>3</inf>-B<inf>2</inf>O<inf>3</inf> glasses was found to be at 0.5 mol% (by 275 nm excitaiton of Gd3+ ion) and 1.5 mol% (by 350 nm excitation of Dy3+ ion) of Dy<inf>2</inf>O<inf>3</inf> concentration. A bright yellow emission corresponding to the transition F<inf>9/2</inf>→H<inf>13/2</inf> (at 576 nm) was found in the emission spectra. This emission band was a mix of blue, yellow, and red. Furthermore, the CIE chromaticity diagram for glass 0.5 mol% Dy<inf>2</inf>O<inf>3</inf> with color coordinates x = 0.368, y = 0.405, and shows white emission. The decay profiles were investigated for 575 emission and values show decreasing trend with increase in Dy<inf>2</inf>O<inf>3</inf> content. Encapsulation of fabricated glasses were made to embed on top of the LED to investigate electro-luminescence spectra. From all results, this glasses could be used for LED encapsulation. © 2022 Elsevier GmbH

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