Investigation of optical properties and energy transfer in Eu(III) and Tb(III) based composite compound dispersed in polar, non-polar solvents and polymer matrix

Abstract

A composite compound (CC) has been developed by the physical mixing of two coordination compounds(1,10-Phenanthroline)tris[4,4,4-trifluoro-1-(2-thienyl)-1,3butanedionato]europium (III) [abbreviated as Eu(TTA)3Phen or ETP] and (1,10-Phenanthroline)tris[2-acetoxybenzoate]terbium(III) [abbreviated Tb(ASA)3Phen or TAP]. Strong photo-physical properties of CC have been used for its study in different liquid medium and in PVA polymer matrix also. The studies of optical as well as structural properties of composite material have been carried out to observe the nature of interaction, energy transfer and migration of energies. The Fourier Transform Infrared (FTIR) spectra of CC show no new bond formation at atomic level and hence both ETP and TAP are entangled to each other by weak interacting forces. The photoluminescence (PL) emission of the Eu3+ ions enhance while of the Tb3+ ions decreases in the CC, indicating migration of energy from Tb3+ to Eu3+ ion. The effect of medium on the optical properties of this composite material has been investigated in detail. The excitation, emission as well as decay profiles of the composite material has been carried out in polar (ethanol), non-polar (Chloroform) as well as in polymer matrix {Poly-vinyl alcohol (PVA) matrix}. The reason behind the different shape and intensity in excitation and emission spectra of the composite material in different medium has been discussed. That concludes maximum fluorescence intensity in PVA matrix and least in polar solvents. In last stage, the plasmonic silver nanoparticles (AgNPs) have been introduced to further enhance the emission intensity in PVA matrix.