Disorder Limited Exciton Transport in Colloidal Single-Wall Carbon Nanotubes
Disorder Limited Exciton Transport in Colloidal Single-Wall Carbon Nanotubes
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DOI：
10.1021/nl301739d
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发表时间：
2012-10-01
期刊：
影响因子：
10.8
通讯作者：
Doorn, Stephen K.
中科院分区：
文献类型：
--
作者：
Crochet, Jared J.;Duque, Juan G.;Doorn, Stephen K.
我们展示了室温下胶体环境中 (6,5) 碳纳米管中 S-1 激子输运的测量结果。与末端猝灭相关的激子扩散长度与光致发光寿命相结合，为确定大约 7.5 cm(2)s(-1) 的中值扩散常数提供了直接基础。我们的实验结果与使用实际激子色散计算的模型扩散常数进行了比较，该模型考虑了由于交换自能以及明暗激子之间的非平衡分布而进行的对数校正。与声声子散射相关的固有扩散常数太大，无法解释观察到的扩散长度，因此，我们将观察到的传输归因于与胶体界面动力学相关的无序限制扩散传输。在该模型中，有效表面电势将激子平均自由程限制为与激子波函数相同的大小，由电子-空穴库仑相互作用的强度定义。
We present measurements of S-1 exciton transport in (6,5) carbon nanotubes at room temperature in a colloidal environment. Exciton diffusion lengths associated with end quenching paired with photoluminescence lifetimes provide a direct basis for determining a median diffusion constant of approximately 7.5 cm(2)s(-1). Our experimental results are compared to model diffusion constants calculated using a realistic exciton dispersion accounting for a logarithmic correction due to the exchange self-energy and a nonequilibrium distribution between bright and dark excitons. The intrinsic diffusion constant associated with acoustic phonon scattering is too large to explain the observed diffusion length, and as such, we attribute the observed transport to disorder-limited diffusional transport associated with the dynamics of the colloidal interface. In this model an effective surface potential limits the exciton mean free path to the same size as that of the exciton wave function, defined by the strength of the electron-hole Coulomb interaction.