Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.354, 795-807, 2000
The antenna effect of Eu(III) cryptate entrapped in xerogel matrices
The europium(III) complex with [biq,2.2] cryptand, where big is 3.3'-biisoquinoline-2.2'-dioxide and complexes with additional secondary ligands such as L,10-phenanthroline (phen) or triphenylphosphine oxide (TPPO) were entrapped by the sol-gel method in silica or silicate xerogel organically modified with methyl groups. The photophysical properties of such materials were studied. The luminescence behaviour of the complexes in the rigid matrix was studied by means of emission, excitation spectra and lifetime measurements. The results indicated that the Eu(III)-[biq,2.2] complex in the methylated silicate xerogel displayed a distinctly higher emission intensity and longer lifetime than in the silica matrix, whereas in the case of the complexes with the secondary ligands these changes were not so pronounced. It was also observed for the silica xerogel with Eu(LII) complex that the emission intensity increased up to 110 degreesC with temperature.