Exciton diffusion, end quenching, and exciton-exciton annihilation in individual air-suspended carbon nanotubes
Exciton diffusion, end quenching, and exciton-exciton annihilation in individual air-suspended carbon nanotubes
复制标题
DOI：
10.1103/physrevb.91.125427
复制
发表时间：
2015-03-19
影响因子：
3.7
通讯作者：
Kato, Y. K.
中科院分区：
文献类型：
--
作者：
Ishii, A.;Yoshida, M.;Kato, Y. K.
激子扩散对碳纳米管的发光特性有很大的影响，它在各种非辐射衰减过程中起着重要的作用。在这里，我们进行光致发光显微镜数百个单独的空气悬浮的碳纳米管，以阐明激子扩散，末端淬火，激子-激子湮灭过程之间的相互作用。从随机行走理论以及蒙特卡罗模拟模型推导出的纳米管长度依赖性和激发功率依赖性的发射强度进行了分析。我们得到了不同手性的激子扩散长度和吸收截面的值，并观察到了与直径相关的光致发光量子产率。模拟还揭示了一维聚结过程的本质，并给出了发射强度与功率关系的解析表达式。
Luminescence properties of carbon nanotubes are strongly affected by exciton diffusion, which plays an important role in various nonradiative decay processes. Here we perform photoluminescence microscopy on hundreds of individual air-suspended carbon nanotubes to elucidate the interplay between exciton diffusion, end quenching, and exciton-exciton annihilation processes. A model derived from random-walk theory as well as Monte Carlo simulations are utilized to analyze nanotube length dependence and excitation power dependence of emission intensity. We have obtained the values of exciton diffusion length and absorption cross section for different chiralities, and diameter-dependent photoluminescence quantum yields have been observed. The simulations have also revealed the nature of a one-dimensional coalescence process, and an analytical expression for the power dependence of emission intensity is given.