Dy3+: B2O3-Al2O3-ZnO-Bi2O3-BaO-M2O (M = Li; Na; and K) glasses: Judd-Ofelt analysis and photoluminescence investigation for WLED applications

Abstract

Authors aim to study multicomponent barium bismuth borate glasses doped with Dy3+ (1 mol%) for white light-emitting diodes (WLEDs) application. All samples, synthesized through melt-quench approach, were characterized by XRD, optical absorption, excitation, emission, and decay lifetimes. Oscillator strengths and Judd-Ofelt intensity parameters (omega(2), omega(4), omega(6)) for all glasses were computed from absorption spectra and further, radiative emission transition probability (A(R)), branching ratio (beta(R)), and radiative lifetime (tau(R)) were estimated for Dy3+ ion various excited states using J-O parameters. Upon 350 nm excitation, I-4(15/2) -> H-6(15/2) [454 nm (blue)], F-4(9/2) -> H-6(15/2) [483 nm (blue)], F-4(9/2) -> H-6(13/2) [575 nm (yellow)], and F-4(9/2) -> H-6(11/2-) [663 nm (red)] emission transitions were observed among which F-4(9/2) -> H-6(13/2) transition exhibits the highest intensity. Dy3+: Li glass showed relatively higher PL intensity and quantum efficiency than Dy3+: Na and Dy3+: K samples. Calculated CIE chromaticity (x = similar to 0.35, y = similar to 0.39) coordinates (lambda(ex.): 350 nm) and CCTs (4749-4890 K) proclaimed overall neutral white light emission from all samples, implying their suitability for WLED applications. Decay lifetimes (tau(exp)) were determined for Dy3+ : F-4(9/2) -> H-6(13/2) transition. Additionally, stimulated emission cross-section (sigma pE\documentclass[12pt] and gain bandwidth (sigma pE\documentclass[12pt] x Delta lambda(eff)) were calculated for respective blue and yellow emission transitions.