单壁碳纳米管中暗激子变亮的多体格林函数理论研究

本文发现了吸附在碳纳米管外壁和管内的有机分子可以调控碳纳米管的光学性质. 本文以手性为(7，0)的单壁碳纳米管与有机分子方酸菁和聚噻吩组成的复合物为例，利用从头算多体格林函数理论研究了物理吸附的有机分子对碳纳米管光激发性质的影响. 碳纳米管的E₁₁和E₂₂吸收峰红移了几十个毫电子伏特. 重要的是，碳纳米管与分子之间的弱相互作用使得(7，0)管原来能量低于E₁₁峰的暗激子获得一定的振子强度，成为亮激子，从而在低能量处产生一个较弱的卫星吸收峰. 吸附分子的类型影响该卫星峰的能量. 这些发现可为调控碳纳米管的发光波长和发光效率提供有价值的信息.

Brightening of Dark Excitons in Single-Walled Carbon Nanotubes: Investigation by Many-Body Green's Function Theory

Optical excitations of the hy-brids, which are assembled by coupling single-walled carbon nanotubes (SWCNTs) with or-ganic molecules through van der Waals interactions, are studied using ab initio many-body Green''s function theory. We take the semiconducting (7,0) SWCNT, the squarylium and oligothiophene molecules as the example. The E₁₁ and E₂₂ absorption peaks of the (7,0) tube can be redshifted by tens of meV. Most importantly, the lowest dark exciton of the (7,0) tube at the lower-energy side of E₁₁ can be brightened by the interaction between the nanotube and molecules. Position of this new satellite ab-sorption peak is influenced by the type of adsorbed molecule. These findings may be useful for tuning the emission energy and emission efficiency of CNTs.