Lu2O3:Eu3+ glass ceramic films: Synthesis, structural and spectroscopic studies

For the first time, transparent and crack free europium-doped lutetia silica sol-gel films were synthesized using the dip-coating technique on silica quartz substrates. In this study, we examined the effects of incorporating polyvinylpyrrolidone (PVP) and silica (SiO2) into different precursor solutions for different Lu-Si molar ratios: 4:1, 6:1, 8:1 and 10:1. Different systems, such as Lu2O3:Eu3+@SiO2 (using the above Lu:Si molar ratios), were synthesized by sol-gel and by dip-coating technique, employing acetylacetonate lutetium and tetraethylorthosilicate as Lu and Si precursors, in order to produce Lu 2O3:Eu3+ (5 mol%)@SiO2 glass-ceramic films. The film microstructure was studied by microRaman spectroscopy (MRS) and X-ray diffraction (XRD) for different Lu:Si molar ratios on films annealed at 700 C. X-ray diffraction results showed that the lutetium oxide cubic phase crystallizes in the silica matrix at 700 C, and the crystallite size of Lu 2O3:Eu3+@SiO2 films varies from 5 nm to 17 nm according to the respective Lu:Si molar ratios. Opto-geometrical parameters determined by m-lines spectroscopy using a 632.5 nm He-Ne laser showed that the Eu3+ doped films heat-treated at 700 C presented a thickness and density of 1.7 μm (8.8 g cm-3), 970 nm (9.2 g cm-3), 1 μm (9.3 g cm-3) and 1.3 μm (9.25 g cm -3) for the Lu:Si = 4:1, 6:1, 8:1 and 10:1 molar ratio systems, respectively. The Lu:Si = 8:1 system 611 nm emission presented an improvement. These results were provided by photoluminescent spectroscopy. © 2014 Published by Elsevier Ltd.