标题：Photoluminescence of Single-Walled Carbon Nanotubes: The Role of Stokes Shift and Impurity Levels
作者：Mu, Jinglin; Ma, Yuchen; Yin, Huabing; Liu, Chengbu; Rohlfing, Michael
作者机构：[Mu, Jinglin; Ma, Yuchen; Yin, Huabing; Liu, Chengbu] Shandong Univ, Sch Chem & Chem Engn, Jinan 250100, Peoples R China.; [Rohlfing, Michael] Univ 更多
通讯作者地址：[Mu, JL]Shandong Univ, Sch Chem & Chem Engn, Jinan 250100, Peoples R China.
来源：PHYSICAL REVIEW LETTERS
摘要：Recent experiments have indicated that dopants and defects can trigger new redshifted photoluminescence (PL) peaks below the E-11 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.