Control of C₆₀ Behavior for High Yield Synthesis of N@C₆₀ in RF-Plasma

抄録

The nitrogen-atom endohedral fullerene (N@C₆₀) with relatively higher purity [molar concentration ratio of N@C₆₀ to pristine fullerene (C₆₀)] has been synthesized by controlling plasma ion irradiation energy (E_i) and C₆₀ behavior. We have examined the relationship between the synthesis purity of N@C₆₀ and E_i which is controlled by changing the substrate bias voltages (V_sub) and gas pressure (P_N2) during the plasma irradiation process. It has been clarified that there is an optimum condition of the nitrogen plasma for the high-purity synthesis of N@C₆₀, which consists of the high-density nitrogen-molecular ions (N₂⁺) with suitable E_i from 40 to 80 eV. In addition, control of C₆₀ behavior contributes to an increase in the reaction between C₆₀ and N₂⁺ to form N@C₆₀, resulting in the synthesis of N@C₆₀ with the highest purity of 0.56 % in the world.