Photoluminescence of single-walled carbon nanotubes: the role of Stokes shift and impurity levels.
Photoluminescence of single-walled carbon nanotubes: the role of Stokes shift and impurity levels.
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DOI：
10.1103/physrevlett.111.137401
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发表时间：
2013-09
影响因子：
8.6
通讯作者：
J. Mu;Yuchen Ma;Huabing Yin;Chengbu Liu;M. Rohlfing
中科院分区：
文献类型：
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作者：
J. Mu;Yuchen Ma;Huabing Yin;Chengbu Liu;M. Rohlfing
最近的实验表明，掺杂剂和缺陷可以触发新的红移光致发光（PL）峰低于E11峰在单壁碳纳米管（SWCNTs）。为了了解新的发光峰的来源，我们采用从头算多体微扰理论对几种典型掺杂和缺陷的单壁碳纳米管的激发态性质进行了理论研究。我们的计算表明，掺杂中心的斯托克斯位移可以高达170 meV，这是远远大于完整的单壁碳纳米管，必须考虑在内。我们发现偶极允许从本地化的midgap和浅的杂质水平，这可以引起明显的PL峰的过渡。另一方面，暗激子的振子强度似乎太小，无法解释新的PL峰。
Recent experiments have indicated that dopants and defects can trigger new redshifted photoluminescence (PL) peaks below the E11 peak in single-walled carbon nanotubes (SWCNTs). To understand the origin of the new PL peaks, we study theoretically the excited-state properties of SWCNTs with some typical dopants and defects by ab initio many-body perturbation theory. Our calculations demonstrate that the Stokes shift in doped centers can be as large as 170 meV, which is much larger than that of intact SWCNTs and must be taken into account. We find dipole-allowed transitions from localized midgap and shallow impurity levels, which can give rise to pronounced PL peaks. Dark excitons, on the other hand, seem to have oscillator strengths that are too small to account for the new PL peaks.