碳纳米管
激子
从头算
辐射传输
材料科学
从头算量子化学方法
碳纤维
原子物理学
凝聚态物理
物理
纳米技术
量子力学
分子
复合材料
复合数
作者
Catalin D. Spataru,Sohrab Ismail‐Beigi,Rodrigo B. Capaz,Steven G. Louie
标识
DOI:10.1103/physrevlett.95.247402
摘要
We present a theoretical analysis and first-principles calculation of the radiative lifetime of excitons in semiconducting carbon nanotubes. An intrinsic lifetime of the order of 10 ps is computed for the lowest optically active bright excitons. The intrinsic lifetime is, however, a rapid increasing function of the exciton momentum. Moreover, the electronic structure of the nanotubes dictates the existence of dark excitons near in energy to each bright exciton. Both effects strongly influence measured lifetime. Assuming a thermal occupation of bright and dark exciton bands, we find an effective lifetime of the order of 10 ns at room temperature, in good accord with recent experiments.
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