Saturation of the photoluminescence at few-exciton levels in a single-walled carbon nanotube under ultrafast excitation.
Saturation of the photoluminescence at few-exciton levels in a single-walled carbon nanotube under ultrafast excitation.
复制标题
超快激发下单壁碳纳米管中少数激子水平的光致发光饱和。
DOI：
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发表时间：
2010
影响因子：
8.6
通讯作者：
J. Fraser
中科院分区：
文献类型：
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作者：
Y.;T. Q. Nhan;M. Wilson;J. Fraser
单个空气悬浮碳纳米管（长度2-5微米）对于低强度共振泵浦表现出高的光量子效率（7-20%）。在超快激发（150 fs）下，发射在非常低的激子数（2-6）下急剧饱和，这归因于在微米长度尺度上的高效激子-激子湮灭。4 ps脉冲激发的类似饱和行为表明非线性吸收不是一个贡献因素。用激子动力学的随机模型拟合得到吸收截面（0.6- 1.8 × 10 ~（-17）cm ~ 2/atom）。
Single air-suspended carbon nanotubes (length 2-5 microm) exhibit high optical quantum efficiency (7-20%) for low intensity resonant pumping. Under ultrafast excitation (150 fs), emission dramatically saturates at very low exciton numbers (2-6), which is attributed to highly efficient exciton-exciton annihilation over micron-length scales. Similar saturation behavior for 4 ps pulse excitation shows nonlinear absorption is not a contributing factor. The absorption cross sections (0.6-1.8x10(-17) cm2/atom) are determined by fitting to a stochastic model for exciton dynamics.