INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
artículos
Título:
Fluorescence of polyaniline films on platinum surfaces. Influence of redox state and conductive domains
Autor/es:
S ANTONEL, P; F. V. MOLINA; ANDRADE, E M
Revista:
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
Editorial:
Elsevier
Referencias:
Lugar: Amsterdam; Año: 2006 p. 1 - 1
ISSN:
0022-0728
Resumen:
The photoluminescence of polyaniline films
onto platinum electrodes has been studied as a function of the polymer
oxidation state between the fully reduced (leucoemeraldine) and half oxidized
(emeraldine) forms. The fluorescence emission spectra have been corrected for
absorption and reflection from the underlying metal surface. From these results
the quantum yield relative to the reduced state as a function of electrode
potential has been obtained. This quantum yield is maximum for the reduced
state and decays between ca. 0.3 and 0.4 V in the standard hydrogen electrode
scale, reaching a minimum value. This behavior is interpreted in terms of three
oxidation states: leucoemeraldine, intermediately oxidized protoemeraldine and
emeraldine, each having different absorption and emission behavior. In the
emeraldine form, the presence of conductive, quasi-crystalline domains is
considered to fully quench emission from excitons located both inside the
domains and within a range equal to the exciton delocalization length. A good
agreement with the experimental data is found