Structural and optical studies on Dy3+ ions doped alkali lead borophosphate glasses for white light applications

Dy3+ ions doped alkali lead borophosphate glasses with chemical compositions of (45-x) H(3)BO(3+)20P(2)O(5)+10Al(2)O(3)+10PbO+15Li(2)CO(3)+xDy(2)O(3) (where x = 0.0, 0.1, 0.25, 0.50, 1.0 and 2.0 wt%) have been prepared by conventional melt quenching technique and their physical, structural and spectroscopic behavior were studied systematically through XRD, FTIR, SEM with EDAX, optical absorption, luminescence and decay measurements. The density and refractive index increase with increasing of Dy3+ ions concentration and accordingly creating more non-bridging oxygen (NBOs) into glass matrix. X-ray diffraction study proves the amorphous nature of the prepared glasses. The FTIR study reveals the presence of BO4, PO4 vibrational groups and the bending of B-O-P, P-O-P units. The surface morphology and existence of elements in the prepared glasses have been studied through SEM with EDAX. The absorption spectra exhibit nine peaks with hypersensitive transition corresponding to H-6(15/2)-> F-6(11/2) at around 1270 nm. The Judd-Ofelt (JO) theory is used to calculate the calculated oscillator strengths, JO intensity parameters, radiative transition probabilities, stimulated emission cross-section and branching ratio for the present glasses. The JO intensity parameters follow the trend as Omega(2)>Omega(6)>Omega(4). The luminescence spectra of the glass sample displayed three emission peaks with high intensity are centered at 478 nm and 574 nm respectively. These attractive luminescence features of the proposed glasses in the white region verified using CIE 1931 diagram useful for the development of white light applications. The decay measurements of the prepared glasses for the state F-4(9/2) were measured and exhibits both single and non-exponential behavior.