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arXiv 0810.5748cond-mat.mes-hallcond-mat.stat-mech
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单壁碳纳米管中扩散限制激子-激子湮灭的时间相关分析

Diffusion-limited exciton-exciton annihilation in single-walled carbon nanotubes: A time-dependent analysis

Ajit Srivastava, Junichiro Kono

摘要:

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。我们还对一维激子的纯随机布朗扩散运动进行了蒙特卡罗模拟,验证了我们的分析结果。最后,我们考虑了这种扩散限制激子-激子湮灭的温度依赖性,并指出在外部磁场中,可以在低温下实现单壁碳纳米管中的高激子密度。

英文摘要:

To provide physical insight into the recently observed photoluminescence saturation behaviors 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, we consider the temperature-dependence of this diffusion-limited exciton-exciton annihilation and point out that high excitonic densities in SWNTs could be achieved at low temperature in an external magnetic field.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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