Influence of gamma irradiation on photoluminescence properties of polycarbonate films doped with Eu3+-β-diketonate complex

Luminescent films composed by doping diaquatris(thenoyltrifluoroacetonate)europium(III) complex [Eu(tta)3(H2O)2] (1% w/w) into a polycarbonate (PC) matrix were prepared and irradiated at gamma radiation with 10, 50 and 100 kGy. The effect of irradiation on the PC matrix can be evaluated by changes in the luminescence properties of the doped system. Changes in photophysical properties due to gamma radiation were observed by emission and excitation spectral data, emission quantum efficiency (η), lifetime (τ) of emitter 5D0 level of Eu3+ ion and Fourier transformed infrared spectra (FTIR). Based on the emission spectra of PC: Eu(tta)3 1% films were observed the characteristic bands arising from the 5D0→7FJ transitions of Eu3+ ion (J=0–4), indicating the ability to obtain the luminescent films. The most intense transition of Eu3+ is the 5D0→7F2 transition, corresponding to a red emission band at 614 nm, indicated that the lanthanide ion is not located in a site with inversion center symmetry. The high luminescence is owing to the efficient energy transfer via triplet state (T) from the tta ligand and polymer to the emitter 5D0 level of the Eu3+ ion. The results suggest that the doped system after gamma irradiation present similar photoluminescence behavior.