Preparation and optical properties of silica sol–gel microparticles functionalized with [Eu(ntac)3][pphendcn] and [Eu(phen)2](NO3)3 complexes

Preparation methods and optical properties of silica sol–gel microparticles functionalized with [Eu(ntac)3][pphendcn] and [Eu(phen)2](NO3)3 [ntac = 1-(2-naphthoyl)-3,3,3-trifluoroacetone, pphendcn = pyrazino[2,3-f][1,10-phenanthroline-2,3-dicarbonitrile, phen = 1,10-phenanthroline] complexes displaying an energy transfer are discussed. Adsorption of [Eu(ntac)3][pphendcn] on the silica surface leads to strong red emitting samples. A method for functionalization of SiO2:Eu3+ with 1,10-phenanthroline is described. Diffuse reflectance spectra, excitation/emission spectra and quantum yield measurements of the investigated solids are presented. The studies are supported by chemical analysis, NMR data, IR spectra and X-ray diffraction measurements of the functionalized powders.