Conductivity, luminescence and vibrational studies of the poly(ethylene glycol) 400 electrolyte based on europium trichloride

Abstract

Poly(ethy1ene glycol) 40O/(EuCl,), electrolytic complexes with 0 5 x 5 0.327 were prepared. The ionic conductivity of these systems was investigated, and the data were satisfactorily well fitted by the empirical Vogel-Tamman-Fulcher equation. Two different conductivity regions depending on the electrolytic complexes compositions were observed. The conformation of the poly(ethy1ene glycol) 400 (PEG 400) in the complexes was investigated by FT-IR and Raman spectroscopies. These investigations suggest that the PEG 400 chains in PEG 400/(EuCl3), present a TGT conformation (T = trans, G = gauche). Moreover, by laser luminescence spectroscopy it was also proved that each Eu3+ ion is coordinated by four oxygen atoms of PEG in a distorted C,, site symmetry.

White light emission ofEu3+-based hybrid xerogels

“…While in the 7 F 1 manifold the three Stark levels are well defined, there is some uncertainly in the identification and energy assignment of the lower-energy split component of the 7 -based oxide glasses and has been also reported for other polymer-based materials modified by europium salts. 17,22 The previously reported local coordination of Eu 3ϩ in POE and POP electrolytes is approximately a C 2v site symmetry. 15,18,19 This same local geometry has also been proposed for EuCl 3 incorporated in POE oligomers.…”

“…15,18,19 This same local geometry has also been proposed for EuCl 3 incorporated in POE oligomers. 22 However, for the U(2000) n Eu͑CF 3 SO 3 ͒ 3 hybrids the J-splitting degeneracy of the 7 F 2 level and the overall broad envelope of the 5 D 0 → 7 F 2 transition strongly suggest that the Eu 3ϩ site symmetry must be of higher order than C 2v . The coordination established between the cations and the oxygens of the triflate anions, recently discussed in a Fourier transform infrared ͑FTIR͒ study, 59 may account for the increase of the local site symmetry of the U(2000) n Eu͑CF 3 SO 3 ͒ 3 hybrids, when compared to U(2000) n EuBr 3 and POE n EuBr 3 .…”

“…Both vibrational and electronic spectroscopic techniques are relevant tools for gaining some insight about the structural molecular characteristics of those amorphous regions. These techniques have been frequently used in various polymer-salt complexes to investigate several aspects of their molecular characteristics, such as, for instance, the conformation of the polymer chains, [5][6][7] the anionic and cationic environments, [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] the vibrational modes of polymer-cation coordination, [9][10][11]24 and ether oxygen-metal ion stretching motions. 10,11,22 In the case of polymer electrolytes incorporating lan-thanide salts, since the first initial reports indicating that trivalent cations were also soluble in POE and poly͑oxypro-pylene͒, POP, 13,14 several papers have been published during this decade showing that the ion-polymer chain interactions can be investigated using the cation emission features, [14][15][16][17][18][19][20][21][22][23][24] and the active vibrational modes of the anions.…”

“…10,11,22 In the case of polymer electrolytes incorporating lan-thanide salts, since the first initial reports indicating that trivalent cations were also soluble in POE and poly͑oxypro-pylene͒, POP, 13,14 several papers have been published during this decade showing that the ion-polymer chain interactions can be investigated using the cation emission features, [14][15][16][17][18][19][20][21][22][23][24] and the active vibrational modes of the anions. 6,[8][9][10][11][12]22,24 In particular, for POE electrolytes incorporating EuBr 3 the observed emission energies have previously been used for determining the average Eu 3ϩ nearest ligands distance, 16,19 the associated local symmetry group, 15,19 and the number of nearest oxygens. 23 Moreover, for these europium-based polymer electrolytes a structural model of chains of interacting coordination shells ͑characterized by the luminescent center and by its nearest ligands oxygens͒ was derived, allowing the determination of the interaction energy between adjacent coordination shells.…”

Effect of Stepwise Replacement of Non-Oxide to Oxide Group on Structural Properties ofBi2O3·LiF·B2<

“…Luminescent materials have always been studied by researchers for their wide range of applications. Noto reported the luminescence spectroscopy of some systems containing rare earth ions [16,17]. Also, bismuth ion acts as an efficient luminescent activator with applications in lasers as a sensitizer for some rare earth ions [18,19].…”