Luminescent LaF₃:Ce-Doped Organically Modified Nanoporous Silica Xerogels

Organically modified silica compounds (ORMOSILs) were synthesized by a sol-gel method from amine-functionalized 3-aminopropyl triethoxylsilane and tetramethylorthosilicate and were doped in situ with LaF3:Ce nanoparticles, which in turn were prepared either in water or in ethanol. Doped ORMOSILs display strong photoluminescence either by UV or X-ray excitation and maintain good transparency up to a loading level of 15.66% w/w. The TEM observations demonstrate that ORMOSILs remain nanoporous with pore diameters in the 5-10 nm range. LaF3:Ce nanoparticles doped into the ORMOSILs are rod-like, 5 nm in diameter and 10-15 nm in length. Compression testing indicates that the nanocomposites have very good strength, without significant lateral dilatation and buckling under quasi-static compression. LaF3:Ce nanoparticle-doped ORMOSILs have potential for applications in radiation detection and solid state lighting.