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.