Bis-ortho-diynyl-arene C60 adducts on SnO2 films for photoelectrochemical cells

Abstract

Bis-ortho-diynyl-arene C60 adducts (BODA-co-C60), a novel pre-network polymer of aromatic enediynes possessing a fullerene core that is prepared by the Bergman cyclopolymerization of bis-ortho-diynyl-arene monomer with C60, have been organized uniformly onto a nanostructured SnO2 electrode by utilizing the simple drop cast method to maximize the intrinsic high solubility of BODA-co-C60, over 2 mg/100 μL in chloroform. The resulting robust and homogeneous film exhibits a continuous smooth absorption with no shoulder, which agrees well with that of a chloroform solution containing BODA-co-C60, suggesting that no aggregation occurs during the solvent evaporation process. White light was irradiated to a BODA-co-C60 thin film employed as the working electrode to generate a relatively high anodic photocurrent in the presence of the I−/I3− redox couple. This is characteristic for the photogalvanic type of photocurrent generation and indicates the successful electron injection from the C60 anions to the SnO2 nanocrystallites, following the photoinduced charge separation. The result with regard to a photocurrent action spectrum allows us to conclude that polyarylene networks covering a C60 core act as solubilizer and are not responsible for the photocurrent generation under white light illumination. Thus, this strategy for fullerene solubilization using polyarylene units is critical to a uniform organizing of C60 onto nanocrystalline SnO2 as a building block, leading to the construction of an efficient light-to-energy conversion system in combination with the light harvester.