Star-shaped conjugated systems derived from dithiafulvenyl-derivatized triphenylamines as active materials for organic solar cells

Hybrid conjugated systems consisting of a triphenylamine core substituted by three dithialfulvenyl moieties have been synthesized and tested as active materials in organic field-effect transistors and photovoltaic devices. UV-vis. spectroscopy Studies demonstrate that, despite their amorphous character shown by X-ray diffraction and differential scanning calorimetry, strong interactions exist in these materials as an aggregative band is observed at low energies. A first evaluation of their potentialities as 1) semiconductor in organic field-effect transistors shows significant hole mobilities. For bilayer photovoltaic devices, a power conversion efficiency of 0.11% is observed and the external quantum efficiency of the cell under monochromatic irradiation shows a non-negligible contribution of the aggregative bind. (c) 2008 Elsevier B.V. All rights reserved.