Doping the Alkali Atom: An Effective Strategy to Improve the Electronic and Nonlinear Optical Properties of the Inorganic Al12N12 Nanocage

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• 作者：Min Niu ; Guangtao Yu ; Guanghui Yang ; Wei Chen ; Xingang Zhao ; Xuri Huang
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：January 6, 2014
• 年：2014
• 卷：53
• 期：1
• 页码：349-358
• 全文大小：592K
• ISSN：1520-510X

文摘

Under ab initio computations, several new inorganic electride compounds with high stability, M@x-Al₁₂N₁₂ (M = Li, Na, and K; x = b₆₆, b₆₄, and r₆), were achieved for the first time by doping the alkali metal atom M on the fullerene-like Al₁₂N₁₂ nanocage, where the alkali atom is located over the Al鈥揘 bond (b₆₆/b₆₄ site) or six-membered ring (r₆ site). It is revealed that independent of the doping position and atomic number, doping the alkali atom can significantly narrow the wide gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) (E_H-L = 6.12 eV) of the pure Al₁₂N₁₂ nanocage in the range of 0.49鈥?.71 eV, and these doped AlN nanocages can exhibit the intriguing n-type characteristic, where a high energy level containing the excess electron is introduced as the new HOMO orbital in the original gap of pure Al₁₂N₁₂. Further, the diffuse excess electron also brings these doped AlN nanostructures the considerable first hyperpolarizabilities (尾₀), which are 1.09 脳 10⁴ au for Li@b₆₆-Al₁₂N₁₂, 1.10 脳 10⁴, 1.62 脳 10⁴, 7.58 脳 10⁴ au for M@b₆₄-Al₁₂N₁₂ (M = Li, Na, and K), and 8.89 脳 10⁵, 1.36 脳 10⁵, 5.48 脳 10⁴ au for M@r₆-Al₁₂N₁₂ (M = Li, Na, and K), respectively. Clearly, doping the heavier Na/K atom over the Al鈥揘 bond can get the larger 尾₀ value, while the reverse trend can be observed for the series with the alkali atom over the six-membered ring, where doping the lighter Li atom can achieve the larger 尾₀ value. These fascinating findings will be advantageous for promoting the potential applications of the inorganic AlN-based nanosystems in the new type of electronic nanodevices and high-performance nonlinear optical (NLO) materials.