Enhancing the Blue Emission of a Borogermanate Glass System (BO, GeO) via Doping with Copper and Europium Cations

The photoluminescence properties of glasses have attracted much interest in the recent trends of technology. Glass can provide a suitable host environment for transition metal or rare earth ions as a powerful activator to achieve the desired luminescence. In this work, a new system of Eu- and Cu-doped borogermanate glass with composition of 80% BO:20% GeO was prepared. The formed glass systems were studied via optical, photoluminescence, XRD and FTIR spectral measurements. The XRD results confirmed the amorphicity and unstructured nature of the prepared samples. The optical absorption spectra revealed no characteristic spectrum in the visible region for the undoped glass, while the CuO-doped glasses demonstrated absorption in a broad band centered at about 770 nm, and the EuO-doped samples showed two visible absorption peaks at 475 and 542 nm. The optical band gap result for G was lower than that for G and G. The photoluminescence spectrum showed stable blue emission for the undoped glass, which was enhanced with Cu and Eu addition. The color coordinates by CIE chromaticity diagram indicated the blue emission of all samples with a slight variation in positions. The FTIR measurements revealed the existence of a combination of the two borate groups (BO) and (BO) besides the Ge-O groups (GeO, GeO), with no distinct effect of dopants. The presence of CuO and EuO affected the density of the borogermanate glass according to the molecular weight and ionic radii of both ions.