The Effects of Self-polarization on Emission and Excitation Spectra of Eu(DBM)3·Phen Doped in Poly(methyl methacrylate)

Eu(DBM)3· Phen was synthesized and its structure was characterized by FT-IR and the elementary analysis. Emission and excitation spectra of rare earth complex in solution of methyl methacrylate and in solid matrix of poly(methyl methacrylate) were measured, and the experiments confirmed that an intermolecular solute-solute interaction occurred for rare earth complex in solution and solid matrix, which resulted in self-polarization. Influence of the self-polarization includes two aspects: one is the red-shift in absorption of organic ligands, and another is the symmetric changing of Eu3+ site in the complex. The self-polarization effect also causes a stretching of molecular bonds and shifting of charging distribution on molecules, altering the energy difference between the ground and excited states of the solute. At low concentration, the host matrix has effect on this phenomenon; but above certain concentration the difference in host matrix disappears. The other factors are also discussed impacting fluorescence property of rare earth doped systems.