Research Of The Alkylated Fullerene Derivative Self-assembled And Optoelectronic Applications

At present, research of fullerenes is a frontier in the field of materials science. The structure and optical properties of fullerene are the focus of the academic circle, therefore fullerene research mainly concentrated in self-assembled micro / nano structure and organic solar cells. However, the self-assemble process of alkylated fullerene derivative is different from that of fullerene itself. The introduction of the alkyl substituent reduce the spatial symmetry of fullerene and the ?-? stacking among the alkyl fullerene derivatives. Therefore,the self-assemble process of alkyl fullerene derivatives is meaningful to study. Considering the difference of the alkyl fullerenes, solution concentration, solvent system, methods of self-assembly, the aim of this thesis is to obtain regular micro morphology and optoelectronic properties of novel alkyl fullerene derivatives.First, four kinds of alkylated fullerene derivatives were designed and synthesized. The purified fullerene products were characterized by MS and 1HNMR. The self-assembly experiments of alkyl fullerene derivatives were studied referring to the factors of solution concentrations, solvent systems, the poor solvent of different alkyl chain length. The alkylated-C60 derivatives were induced to the C60 solution to probe the interactions between the molecules. The SEM results showed that the locations of the alkyl chain have an impact on self-assembly of alkyl fullerene derivatives. C60-m-hexyl with alkyl chains in the meta position was difficult to get regular morphologies, while the C60-p-hexyl with alkyl chain in the para position was more likely to self-assemble to form a regular morphology. Meanwhile,comparing with C60 which usually forms the regular, three dimensional morphology, the alkylated fullerenes tend to formed sheets. On the impact of the solvent, alkylated fullerene derivatives in CCl4 were easier to generate flower or spherical structure and the poor solvent with the different length of carbon chains can affect the size of the morphology. The SEM results showed that the increasing of length of alkyl chains of poor solvent would reduce the size of the structures in CCl4. Exploration for photoelectric properties of the alkylated fullerene derivatives were explored via UV absorption spectrum, electrochemical tests and organic solar cell measurement. The results showed that alkylated fullerene derivatives have stronger light absorption and better redox reversibility. The C60-m-hexyl as acceptor in active layer for manufacturing solar cell devices got a meaningful result.