Effect of Dysprosium and Samarium RE ion Co-doping on photoluminescence behaviour of novel alkali fluoride bismuth borate glasses: A white LED material

Being inspired from the good spectroscopic traits of alkali fluoride doped borate glasses, a glass series with composition 60B2O3 + 30LiF +10Bi2O3 + (1-x) Dy2O3 + xSm2O3 (where x = 0, 0.2, 0.5, 0.7 and 1 mol%) was prepared by melt quench technique and their Structural, Physical, Optical and Lifetime decay properties were studied and analysed. Prepared samples were X-ray amorphous and their FTIR spectra confirmed that the network is composed of bismuth and borate units. Linear and Non-linear optical properties were studied via UV-Vis-NIR absorption spectra and the variation was found to be influenced by the ratio of RE ions (Dy3+ and Sm3+). Negative values of bonding parameter (delta) were obtained for both the RE ions by nephelauxetic effect and suggested that ionic character of prepared glasses was enhanced by Sm3+ ion co-doping. Emission spectra were recorded for a variety of excitation wavelengths and CIE coordinates, Correlated Colour Temperature (CCT), Colour Rendering Index (CRI) and Colour purity % were calculated. Lifetime decay curves of Dy3+ level 4F9/2 and Sm3+ level 4G5/2 were recorded. CIE coordinates of all compositions, under excitation wavelength 349 nm were displayed in 1931 CIE diagram that indicated improved cool white light emission in Dy3+ and Sm3+ co-doped matrix. The obtained colour parameters inferred that a single matrix is capable of emitting diverse colours with variation of excitation wavelengths and RE ion concentration.

Automated summary

A glass series doped with alkali fluoride in borate glasses was prepared and studied for its structural, physical, optical, and lifetime decay properties. The ratio of RE ions influenced the optical properties, and the glass showed enhanced ionic character by Sm3+ ion co-doping. The glass exhibited diverse emission colors that varied with excitation wavelengths and RE ion concentration.