Synthesis and Functional properties of a novel Dendronized Electropolymer

FABIANA D'ERAMO; LUIS OTERO; LEONIDES SERENO; KEN WONG; FERNANDO FUNGO

Tandil

Congreso; XV Congreso Argentino de Fisicoquímica y Química Inorgánica; 2007

AAFQ

Dendrimers are regularly and hierarchically branched macromolecules with numerous chain ends, all-emanating from a single core. Functional groups (chromophores or electron donor-acceptor moieties) can be accurately located at the core, focal point, periphery, or even at each branching point of the dendritic structure. Dendrimer chemistry expanded rapidly because of its significance both in basic research and in applications. Particular attention has been paid to the photoactive and electroactive dendrimers, which are useful in optoelectronic application as organic light-emitting diodes (OLEDS). A large number of dendrimers with core or end-capping electroactive sites has been synthesized.[[1],[2]] On the other hand, many efforts have been ongoing to develop novel hole-transport polymers, a key material for improving the efficiency of advanced electronic or electro-optic devices. Dendrimers provide new opportunities for precisely placing some charge-carrier transporting units by the generation in a three-dimensional nanoscale construction. Within the charge transport field, carbazole molecules are quite interesting due to their own photophysical and redox properties, which make them suitable as hole carriers.[[3]] In this work, we describe the synthesis and functional properties of dendronized fluorenes-carbazole units (Figure 1) with a redox gradient, where the peripheral carbazole moieties exhibit lower oxidation potentials than those of fluorene units in the interior. This strategy allowed us to obtain a new electropolymeric structure with interesting electronic and optical properties. The polymer film shows good conductivity, reversible electrochemical processes and stable color change with high coloration efficiency and contrast ratio when the polymer was switched between the neutral and oxidized states under aerobic conditions, showing that the polymer film is a promising material as hole-and electron-transporting in optoelectronic organic devices. [1] I. Cuadrado, M. Casado, M. Moran, J. Losada, V. Belsky, J. Am. Chem. Soc. 119, 1997, 7613. [2] C. Valerio, J.L. Fillaut, J. Ruiz, Z.J. Guittard, J.C. Blais, D. Astruc. J. Am. Chem. Soc. 119, 1997, 2588. [3] Morin, J.-F.; Leclerc, M.; Ade,  D.; Siove, A.; Macromol. Rapid Commun. 2005, 26, 761.