Propriedades ópticas do poliestireno sulfonado dopado com íons de neodímio

Abstract

In this work we present the synthesis and optic characterization of sulfonated polystyrene films (PSS) doped with ions of neodymium (Nd). The synthesis has a low cost and a simple route. The used dopant was the neodymium nitrate. The maximum incorporation of ions Nd3+ in the matrix, gotten in the synthesis of the films, was around 14.0 %. The absorption spectra in UV-Vis-NIR of the films of Nd-PSS had presented the characteristic bands for neodymium in aqueous solution. The FTIR spectra had presented a significant widening of the bands in relation to the sulfonated polystyrene spectrum. In this same spectrum occurs a great change in the form of line of the Nd-PSS film in the region below of 1400 cm-1 referring to the vibration of linking N-O. The films measured by Raman spectroscopy have presented the same intensity and localization of the peaks, independently of the region of incidence of the laser in the film. The analysis of these spectra demonstrates the overlapping of the bands: stretching of linking S-O, anti-symmetrical stretching of nitrate and the fold is of the plan of linking N-O. This fact proves the doping of the H-PSS and that the Nd07 film (contends the precursory neodymium solution 0.7 mol/L) is of higher concentration. The luminescence spectrum in UV-Vis region had shown that when the PSS polymer matrix is doped a blue shift is observed. The luminescence spectra excited in 458 nm (absorption band of the HPSS) and in 514 nm (absorption band of the Nd3+ ion) indicate, respectively, that it has an aiding of the emission around 520 nm (green) and of 610 nm (orange). The spectra of selective excitement show that it has an overlapping of the bands of excitement of the PSS with the Nd-PSS, when the wavelength of excitement varies of 400 until 500 nm. The bands of the Nd-PSS became wider and are more definite. The films of Nd- PSS present an intense emission in the infrared in 1076 nm (radiative transition 4F3/2®4I11/2). It was not observed dependence with the concentration in all spectra done. The factor of spectroscopic quality of the Nd11 film, gotten for the parameters of Judd-Ofelt, indicates that the domain of the transistion occurs in 4F3/2 ® 4I11/2 (1076 nm), proving with the results of the measures made in the photoluminescence in the infra-red. This confirms that the Nd11 film is an excellent candidate to be used in optic devices.