Luminescence behavior of PMMA films doped with Tb(III) and Eu(III) complexes

Novel hybrid systems based on the poly(methyl methacrylate) (PMMA) matrix and Eu(III) and Tb(III) tris(β-diketonates) complexes with 1,10-phenanthroline were synthesized and analyzed as light-conversion materials. Solutions of the Tb(III) and Eu(III) complexes doped into PMMA were spin-coated to fabricate films with various concentrations of luminophores. Long hydrocarbon substituents in the structure of complexes inhibit their crystallization. In turn, it allows to vary the luminophore content in a polymer matrix in a broader range and achieve the maximum of emission with higher concentrations of dopants. The addition of the Tb(III) complex to the system results in a 26% increase in the relative luminescence quantum yield of the Eu(III) ions due to an additional energy transfer from the Tb(III) compound. The results of this work illustrate that although the Eu(III) and Tb(III) complexes exhibit lower rate and efficiency of energy transfer than their well-known Tb(acac)3 and Eu(tta)3 analogues, the structural features of lanthanide complexes allow to efficiently dope a PMMA matrix with considerably larger amounts of luminophores. It offers broader application opportunities for the coordination Ln(III) compounds as polyfunctional materials for optics and optoelectronics.