Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/64537
Type: Artigo de periódico
Title: Electronic properties of poly(thiophene-3-methyl acetate)
Author: Gomes, AL
Casanovas, J
Bertran, O
Campos, JSD
Armelin, E
Aleman, C
Abstract: The electronic structure of poly(thiophene-3-methyl acetate) has been investigated using UV-vis absorption spectroscopy and quantum mechanical calculations. Experimental measures in chloroform solution indicate that the pi-conjugation length increases with the polymer concentration, which is reflected by the red shift of the absorbance peak of the pi-pi* transition. On the other hand, the energy required for the pi-pi* transition has been found to decrease with the volatility of the solvent for concentrated polymer solutions, even though the influence of the solvent is very small for dilute solutions. Quantum mechanical calculations indicate that the interactions between the pi-conjugated backbone and the methyl acetate side groups are very weak. On the other hand, the lowest energy transition predicted for an infinite polymer chain that adopts the anti-gauche and all-anti conformations is 2.8 and 1.9 eV, respectively. Finally, measurements on spin-casted nanofilms reflect that the pi-pi* transition energy increases with the thickness, which has been attributed to the distortion of the molecular conformation. In spite of this, the energy gap obtained for the thinnest film (1.52 eV) is significantly smaller than that determined for dilute and concentrated chloroform solutions (2.56 and 2.09 eV, respectively).
Subject: Conducting polymers
Polythiophene
UV-vis spectroscopy
Quantum chemistry
Conjugation
Country: Holanda
Editor: Springer
Rights: fechado
Identifier DOI: 10.1007/s10965-010-9556-4
Date Issue: 2011
Appears in Collections:Unicamp - Artigos e Outros Documentos

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