Diffusion-limited exciton-exciton annihilation in single-walled carbon nanotubes: A time-dependent analysis
Diffusion-limited exciton-exciton annihilation in single-walled carbon nanotubes: A time-dependent analysis
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单壁碳纳米管中的扩散限制激子-激子湮灭：时间依赖性分析
DOI：
10.1103/physrevb.79.205407
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
J. Kono
中科院分区：
文献类型：
--
作者：
A. Srivastava;J. Kono
为了提供物理洞察到最近观察到的单壁碳纳米管的光致发光饱和行为，这意味着激子密度的上限的存在，我们已经进行了一个依赖于时间的理论研究扩散限制激子-激子湮灭的反应扩散过程中的一般情况下，存在确切的治疗。通过将辐射复合衰减作为泊松过程包含在一维扩散驱动的两粒子湮灭的精确可解问题中，我们能够正确地将激子的动力学建模为具有不同初始密度的时间函数，这反过来又使我们能够再现实验观察到的高激子密度下的光致发光饱和行为。我们还进行了蒙特卡罗模拟的纯随机，布朗扩散运动的一维激子，这验证了我们的分析结果。最后，通过考虑这种扩散限制激子-激子湮灭的直径、手性和温度依赖性，我们指出，在低温下，在外部磁场中，单壁碳纳米管中可以实现高激子密度。
To provide physical insight into the recently observed photoluminescence saturation behavior in single-walled carbon nanotubes implying the existence of an upper limit of exciton densities, we have performed a time-dependent theoretical study of diffusion-limited exciton-exciton annihilation in the general context of reaction-diffusion processes, for which exact treatments exist. By including the radiative recombination decay as a Poissonian process in the exactly solvable problem of one-dimensional diffusion-driven two-particle annihilation, we were able to correctly model the dynamics of excitons as a function of time with different initial densities, which in turn allowed us to reproduce the experimentally observed photoluminescence saturation behavior at high exciton densities. We also performed Monte Carlo simulations of the purely stochastic, Brownian diffusive motion of one-dimensional excitons, which validated our analytical results. Finally, by considering the diameter, chirality, and temperature dependence of this diffusion-limited exciton-exciton annihilation, we point out that high exciton densities in single-walled carbon nanotubes may be achieved at low temperature in an external magnetic field.