Water-activated photoluminescence of europium(III) β-diketonate complex in a porous glass matrix

Europium(III) β-diketonate complex Eu(DBM)3 · phen (DBM = dibenzoylmethane, phen = 1,10-phenanthroline) have been encapsulated in a porous glass matrix by impregnating it with an acetone solution of the complex. Subsequent filling of the pore space with water leads to a significant increase in the intensity of photoluminescence from the deposited complex molecules. A key role in the unusual behavior of the system belongs to the coordination environment of Eu3+ that ensures screening of these ions from water molecules and increases the efficiency of indirect excitation of emission by increasing the rate of π → π* transitions in the ligand system in the presence of water condensed in the pores.