Cool white light emission from Dy3+-doped SiO2 - Bi2O3 - Ga2O3 - B2O3-GeO2- TeO2 glasses: Structural and spectroscopic properties

The authors aim to study multi former oxide glasses doped with different concentrations of Dy3+ (0.00, 0.5, 1.0, 1.5, and 2 mol%) for white light-emitting application. All samples characterized by XRD, FTIR, and optical properties (absorption, excitation, and emission). The optical band gap calculated by a differential method. FTIR spectra confirm the network composed of GaO4, GeO4, TeO4, and BO4 tetrahedra, BO3 triangles, B-O-B linkages, and SiO4 tetrahedra with one NBO. In addition to the TeO3, BiO3, TeO6, and BiO6 vibration groups. Oscillator strengths and Judd-Ofelt parameters (Omega 2, Omega 4, Omega 6) calculated and found that the glass samples had a variable trend from Omega 2 > Omega 4 > Omega 6 to Omega 2> Omega 6 > Omega 4, at a Dy2O3 content >1 mol%. Furthermore, radiative emission transition probability (AR), branching ratio (beta R), and radiative lifetime (tau R) estimated for Dy3+ ion in various excited states using J-O parameters. Upon 454 nm excitation, 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) [680 nm (red)] emission. Among them, it noticed that the transition F-4(9/2) -> H-6(13/2) shows the highest intensity. The CIE chromaticity coordinates, correlated color temperature (CCT), and color purity (CP) indicate a generally neutral white light emission from all samples, which meant their suitability for optical applications. Determination of the white light coordinated from the CIE program, which verifies the values of samples are close to the pure white light. And sample containing 2 mol% Dy3+ close to the standard CIE D65 glow.