Transient grating measurements of excitonic dynamics in single-walled carbon nanotubes: The dark excitonic bottleneck
Transient grating measurements of excitonic dynamics in single-walled carbon nanotubes: The dark excitonic bottleneck
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DOI：
10.1021/nl061646d
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发表时间：
2006-08-09
期刊：
影响因子：
10.8
通讯作者：
Apkarian, V. A.
中科院分区：
文献类型：
--
作者：
Seferyan, H. Ye.;Nasr, M. B.;Apkarian, V. A.
瞬态光栅测量证实了单壁碳纳米管（SWNT）的激子模型，通过确定暗激子(D)是半导体碳纳米管（S-SWNT）的种群松弛瓶颈。这些数据可以重建激子级联和冷却的动力学，从带连续到基态的振动冷却。在S-SWNT中，带内弛豫发生在40 fs，定位到2(g)激子发生在50 fs，然后是激子级联：2(g) -> 1(u) -> D -> 1(g)，时间常数分别为175 fs， 3 ps, 300 ps。来自1(u)态的荧光被有效的种群转移到D-1暗激子所猝灭。在金属管中，冷却在1ps的时间尺度上完成。
Transient grating measurements affirm the excitonic model for single-walled carbon nanotubes (SWNT) by identifying the dark exciton ( D) as the population relaxation bottleneck in semiconducting-SWNT (S-SWNT). The data allow the reconstruction of the kinetics of excitonic cascade and cooling, from band continuum to vibrational cooling in the ground electronic state. In S-SWNT, the intraband relaxation occurs in 40 fs, localization into the 2(g) exciton occurs in 50 fs, followed by the excitonic cascade: 2(g) -> 1(u) -> D -> 1(g) with time constants of 175 fs, 3 ps, 300 ps, respectively. Fluorescence from the 1(u) state is quenched by efficient population transfer to D-1 dark exciton. In metallic tubes, cooling is completed on the time scale of 1 ps.