LUMINESCENCE OF NONHYGROSCOPIC POLYMER ELECTROLYTES MODIFIED BY EUROPIUM PICRATE COMPLEXES

The luminescence features of new europium-based PEO electrolytes where the lanthanide ion is encapsulated into a ligand structure cage (eg E u3+-picrate complexes with trans-1,4-dithiane-1,4-dioxide, TDTD) were reported. The complexes are non-hygroscopic and strongly luminescent i n the temperature range of 10 to 300 K. The emission spectra were reco rded in this temperature range and the corresponding lines assigned to the D-5(0.1)-->F-7(0-4) transitions. The measured line widths, which are of the same order of magnitude of the one observed in crystals (1- 2 Angstrom), are approximately,two orders of magnitude sharper than th e ones observed in glasses and other Eu3+ based polymeric materials. T he Stark components of the F-7(0.4), D-5(0) levels and the correspondi ng barycenters were calculated;and modeled by the superposition of the free ion Hamiltonian with a local-field perturbation. The average cat ion-nearest ligand distance was determined for the PEO-Eu(pic)(3)TDTD1 .5 complexes and the results obtained, (-)(R)=2.45 A, agree very well with the X-ray average ion-nearest ligands distances measured for the picrate salt, (-)(R)=2.448 Angstrom. (C) 1998 Published by Elsevier Sc ience Ltd. All rights reserved.