Preparation of Fullerene Derivative Thin Films by Electrospray Deposition Method

Abstract

Thin films of fullerene derivative were prepared by an electrospray deposition (ESD) method using six types of fullerene derivatives (a series of [6,6]-Phenyl-C₆₁-butyric acid ester and adducts of C₆₀ with indene). The optimized conditions for fabricated thin films were investigated by ESD process using 1.0 mg/mL diluted solutions of the fullerene derivatives : the spray diameter as a function of the supply rate by changing the applied voltages. In all the cases, the spray diameters increased with increasing applied voltage reaching the maximum diameter (D_max) at the voltage (V_Dmax) and decreasing for higher voltage. The scanning electron microscope observation of the successfully fabricated thin films showed the imbricated structure formed by the stacking of fullerene derivative sheets. The atomic force microscope image revealed that the highest density of imbricated structure was obtained at V_Dmax, and the root-mean-square roughness of the film surface decreased sharply reaching at the voltage. These findings suggest that the ESD method is expected to be effective to prepare a fullerene derivative thin film for the production of organic devices.