Optically active nano-glass-ceramic coatings of Nd3+doped-80SiO2-20LaF3 prepared by the pre-crystallized nanoparticles sol-gel route

Transparent oxyfluoride glass-ceramic (OxGCs) coatings with composition 1.2Nd3+ 80SiO2- 20LaF3 were pre-pared following a sol-gel route labelled "pre-crystallized nanoparticles route". OxGCs are transparent materials composed by one or more fluoride nanocrystals in a glass matrix. OxGCs have been prepared by sol-gel with encouraging results in powders and bulk glass-ceramics but not in coatings. In the present work, aqueous sus-pensions of LaF3 nanoparticles doped with Nd3+ were prepared by chemical route and then incorporated into a silica sol to obtain 1.2Nd3+ doped-80SiO2-20LaF3 particulate sols. Nd3+-LaF3 suspensions are characterized by XRD, HRTEM, and XRF revealing the presence of LaF3 as the unique crystalline phase. Then, 1.2Nd3+ -80SiO2- 20LaF3 coatings were prepared by dip-coating and characterized by XRD, FTIR, and Ellipsometry. Photo-luminescence measurements were performed for LaF3 nanoparticles and OxGCs coatings, confirming the pres-ence of Nd3+ in the nanocrystals and showing well-structured crystalline-like emission spectra with lifetimes of 520 and 440 mu s respectively.