Modulation of the work function of fullerenes C₆₀ and C₇₀ by alkali-metal adsorption: A theoretical study

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• 作者：Hong Liang ; Shunfu Xu ; Weihui Liu ; Yueqiang Sun ; Xiangfa Liu ; Xinqing Zheng ; Sen Li ; Qiang Zhang ; Ziliang Zhu ; Xiaochun Zhang ; Chengguo Dong ; Chun Li ; Guang Yuan ; Hitenori Mimura
• 关键词：Alkali metal ; Fullerene ; Adsorption position ; Vacancy defect ; First-principles calculation
• 刊名：Physics Letters A
• 出版年：2013
• 出版时间：15 November, 2013
• 年：2013
• 卷：377
• 期：38
• 页码：2676-2680
• 全文大小：1678 K

文摘

The impact of alkali-metal (Li/Na/Cs) adsorption on work function of fullerenes C₆₀ and C₇₀ was investigated by first-principles calculations. After adsorption, the work functions of fullerenes C₆₀ and C₇₀ decrease distinctly and vary linearly with the electronegativity of the alkali metal elements, and the positions where the alkali atoms are adsorbed considerably influence the work functions. On the contrary, a vacancy defect elevates the work functions of the fullerenes C₆₀ and C₇₀. The variation in the work functions rests with variation in Fermi level (which are attributed to charge transfer) and variation in vacuum levels (which are attributed to the induced dipole moments). Moreover, alkali-metal adsorption can also improve the electric conductivity of a fullerene mixture of C₆₀ and C₇₀.