Synthesis and photoluminescence of the Eu3+ composite with dibenzoylmethane and oligoacrylic acid

An Eu3+-dibenzoylmethide (DBM)-oligoacrylic acid (OAA) composite was prepar ed in water, ethanol, and a glycerin mixed solvent; Influence of pH value o n the synthesis was also given. A composite with pH of 10.0 was most suitab le for the synthesis. It was confirmed by UV-VIS, Fourier transform infrare d (FTIR), excitation spectra, and conductivity measurement that DBM, the se cond ligand, which had low molecular weight, coordinated with Eu3+ in the i onomer chain, instead of dispersing in the OAA matrix. When the molar ratio of DBM-Eu3+ was 2:1, which was found to be ;the best ratio to obtain the m aximum intensity of fluorescence (due to the D-5(0) --> F-7(2) transition), the fluorescence intensity of the Eu3+-DBM-OAA (emitted at 616 nm) increas ed logarithmically with the increase of the molar ratio of Eu3+-OAA in the range of 0 to 6 : 1. Energy transfer in the composite was also discussed. ( C) 1999 John Wiley & Sons, Inc.