Fabrication and Properties of Fullerodendron Thin Films

Thin films of fullerodendron (C60(Gn-COOMe) (n = 0.5, 1.5, 2.5)), which was synthesized from fullerene and anthracenyl poly(amido amine) dendron with methyl ester terminals and different generations (G), were fabricated by the Langmuir−Blodgett (LB) and adsorption techniques. It was characterized by X-ray reflectometry that the LB films possessed well-ordered structure, although the adsorption method led to random orientation of molecules. As to C60(G0.5-COOMe) and C60(G1.5-COOMe), the LB films took a four-layer structure consisting of a double layer of molecules, and fullerene moieties exist in the interior of the LB films. On the other hand, C60(G2.5-COOMe) led to a two-layer structure in which the fullerene moieties were at the air side and the dendron moieties were at the substrate side. With increasing generation of dendron, the monolayer formation ability at the air/water interface as amphiphilic molecule strengthens and the amphiphilic property becomes superior to the fullerene−fullerene attractive interaction that prevents the monolayer formation. Furthermore, in the case of C60(G0.5-COOMe) and C60(G1.5-COOMe), the reduction peak in cyclic voltammetry of the LB film remained even after UV light irradiation. On the contrary, the peak of the C60(G2.5-COOMe) LB film disappeared, indicating that molecular arrangement in the films affects electrochemical properties.