Luminescent properties of an Yb podate in sol-gel silica films, solution, and solid state

In search of IR emitting materials a complex of Yb^III with an octadentate ligand bearing four bidentate 8-hydroxyquinolinate subunits connected to a N,N,N′,N′-tetra-aminopropyl-1,2-ethylenediamine anchor [S. Comby, D. Imbert, A.S. Chauvin, J.C.G. Bünzli, Inorg. Chem. 45 (2006) 732.] has been incorporated into silica glasses obtained by a special two-step, catalyzed sol-gel method. Photophysical properties of the resulting thin films are investigated and compared to those of an aqueous solution 10^-3 M in HBS buffer (pH 7.4) and of a solid state sample, at room temperature and 10 K. They point to the chelate withstanding the sol-gel process; moreover the lifetime and quantum yield are comparable and even slightly better than in aqueous solution.