Please use this identifier to cite or link to this item: http://www.repositorio.ufop.br/handle/123456789/4776
Title: Influence of intensive light exposure on the complex impedance of polymer light-emitting diodes.
Authors: Cury, Fábio Rogério
Cazati, Thiago
Bianchi, Rodrigo Fernando
Keywords: Polymer
Device
Photoconductivity
Interface
Issue Date: 2008
Citation: CURY, F. R.; CAZATI, T.; BIANCHI, R. F. Influence of intensive light exposure on the complex impedance of polymer light-emitting diodes.. Materials Research, v. 11, p. 213-215, 2008. Disponível em: <http://www.scielo.br/pdf/mr/v11n2/a17v11n2.pdf>. Acesso em: 23 fev. 2015.
Abstract: In this work we investigated the effect of visible radiation on the electrical properties of poly[(2-methoxy-5 hexyloxy)-p-phenylenevinylene]– MH-PPV films and light emitting diodes. Complex impedance measurements of (Au or ITO)/MH-PPV/(Au or Al) samples were carried out at room temperature and exposed to white light. Over the frequency range from 100 mHz to 2 MHz, the electrical results of Au/MH-PPV/Au was dominated by the Cole-Cole approach, where the electrode influence is negligible. However, some additional influence of the interface was observed to occur when Al was used as electrode. These effects were observed under both dark and visible-light illumination conditions. A simple model based on resistor-capacitor parallel circuits was developed to represent the complex impedance of the samples, thereby separating bulk and interface contributions. We observed that the polymer electrical resistivity decreased while the dielectric constant of the polymer and the thickness of the Al/MH-PPV layer were almost constant with increasing light intensity. The decrease of the polymer layer resistance comes from a better charge injection due to a light induced dissociation of positive charge carriers at the electrode.
URI: http://www.repositorio.ufop.br/handle/123456789/4776
metadata.dc.identifier.doi: http://dx.doi.org/10.1590/S1516-14392008000200017
ISSN: 1516-1439
metadata.dc.rights.license: O periódico Materials Research dá permissão ao RI/UFOP para depositar uma cópia eletrônica dos artigos publicados por esse periódico em que ao menos um dos autores é aluno ou professor da UFOP. Contato via email em 25 out. 2013.
Appears in Collections:DEFIS - Artigos publicados em periódicos

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