Chmeliov Jevgenij, Narkeliunas Jonas, Graham Matt W, Fleming Graham R, Valkunas Leonas
Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Ave. 9, LT-10222 Vilnius, Lithuania.
Department of Physics, Oregon State University, 301 Weniger Hall, Corvallis, Oregon 97331, USA.
Nanoscale. 2016 Jan 21;8(3):1618-26. doi: 10.1039/c5nr06853c.
We present a thorough analysis of one- and two-color transient absorption measurements performed on single- and double-walled semiconducting carbon nanotubes. By combining the currently existing models describing exciton-exciton annihilation-the coherent and the diffusion-limited ones-we are able to simultaneously reproduce excitation kinetics following both E11 and E22 pump conditions. Our simulations revealed the fundamental photophysical behavior of one-dimensional coherent excitons and non-trivial excitation relaxation pathways. In particular, we found that after non-linear annihilation a doubly-excited exciton relaxes directly to its E11 state bypassing the intermediate E22 manifold, so that after excitation resonant with the E11 transition, the E22 state remains unpopulated. A quantitative explanation for the observed much faster excitation kinetics probed at E22 manifold, comparing to those probed at the E11 band, is also provided.
我们对在单壁和双壁半导体碳纳米管上进行的单色和双色瞬态吸收测量进行了全面分析。通过结合目前现有的描述激子 - 激子湮灭的模型——相干模型和扩散限制模型——我们能够同时再现E11和E22泵浦条件下的激发动力学。我们的模拟揭示了一维相干激子的基本光物理行为和非平凡的激发弛豫途径。特别是，我们发现非线性湮灭后，双激发激子直接弛豫到其E11态，绕过中间的E22多重态，因此在与E11跃迁共振激发后，E22态保持未填充状态。还提供了一个定量解释，说明与在E11能带探测到的激发动力学相比，在E22多重态探测到的激发动力学要快得多。
