Search

N-Ethylcarbazole (NECZ) or carbazole (CZ) and bithiophene (BT) have been used as a mixture of monomers for the formation of electrodeposited polymer and copolymer films on platinum electrode. When beginning with a NECZ–BT mixture, the peak intensity resulting from the composite film cycling decreases with increasing initial NECZ proportion until that proportion reaches 40%. For higher NECZ proportions, no deposit could be obtained. Infrared spectra of the deposits show the presence of the characteristic bands of both monomer units in the material. In the case of CZ–BT mixtures, the electrochemical behaviours of the composite films are close to those displayed by the homopolymers, i.e. polybithiophene or dicarbazyle, containing respectively low and high proportions of CZ. Furthermore, infrared and ultraviolet-visible studies of deposits obtained for various CZ proportions yield spectra that vary according to monomer proportion. [Copyright &y& Elsevier]

New alternating copolymers derived from thieno[3,4-c]pyrrole-4,6-dione (TPD) and 2,7-carbazole moieties havebeen synthesized by Suzuki cross-coupling reaction and characterized.These polymers combine interesting properties such as good solubilityand excellent thermal and air stability. The present studies indicatethat the combination of TPD and 2,7-carbazole building blocks canbe a very effective way to lower the HOMO energy level and ultimatelyto enhance the Vocof polymer solar cells.The Vocreported here (up to 1.07 V) isone of the highest observed for polymer:[60]PCBM bulk heterojunctiondevices, and preliminary results on the photovoltaic devices (powerconversion efficiencies up to 1.8%) indicate that performance couldprobably be improved by increasing the molecular weights and by fine-tuningthe electronic properties and the morphology. [ABSTRACT FROM AUTHOR]

Abstract: A conjugated oligomer containing central bi-ethylenedioxythiophene (BEDOT) unit and two terminal anil-substituted carbazole units has been characterized by cyclic voltammetry and spectroelectrochemical methods (UV–vis–NIR and Raman). It shows two oxidation waves at −0.01V and +0.24V (versus Fc/Fc+), which can be ascribed to two successive oxidative dopings of the molecule. The molecule is transmissive sharp yellow when fully reduced, transmissive green upon oxidation up to the end of the first oxidative process, and dark blue upon full oxidation. UV–vis–NIR and Raman spectroelectrochemical investigations show that the colour changes within the potential of the first oxidation wave are associated with the oxidation of both carbazole and ethylenedioxythiophene subunits whereas the electrochromic effect in the potential range of the second oxidation wave involves predominantly the oxidation of the ethylenedioxythiophene subunits. [Copyright &y& Elsevier]