Direct observation of deep excitonic states in the photoluminescence spectra of single-walled carbon nanotubes.
Direct observation of deep excitonic states in the photoluminescence spectra of single-walled carbon nanotubes.
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DOI：
10.1103/physrevlett.99.237402
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发表时间：
2007-12
影响因子：
8.6
通讯作者：
O. Kiowski;K. Arnold;S. Lebedkin;F. Hennrich;M. Kappes
中科院分区：
文献类型：
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作者：
O. Kiowski;K. Arnold;S. Lebedkin;F. Hennrich;M. Kappes
最近预测低能暗激子态位于半导体单壁碳纳米管中的第一个亮 (E11) 激子下方 [Phys.莱特牧师。 93, 157402 (2004)10.1103/PhysRevLett.93.157402]。衰变成如此深的激子态被认为是降低光致发光量子产率的机制。在这项研究中，我们首次直接观察到单壁碳纳米管中的深激子。悬浮半导体单壁碳纳米管 (SWNT) 的光致发光 (PL) 显微镜显示，相对于主 E11 PL 发射峰，弱发射卫星红移了约 38-45 meV 和约 100-130 meV。在水表面活性剂分散体中的单壁碳纳米管集合的 PL 测量中也发现了类似的卫星，红移 95-145 meV，具体取决于纳米管种类。这些深激子发射特征的相对强度取决于纳米管周围环境。
Low-energy, dark excitonic states have recently been predicted to lie below the first bright (E11) exciton in semiconducting single-walled carbon nanotubes [Phys. Rev. Lett. 93, 157402 (2004)10.1103/PhysRevLett.93.157402]. Decay into such deep excitonic states is implicated as a mechanism which reduces photoluminescence quantum yields. In this study we report the first direct observation of deep excitons in SWNTs. Photoluminescence (PL) microscopy of suspended semiconducting single-walled carbon nanotubes (SWNTs) reveals weak emission satellites redshifted by approximately 38-45 and approximately 100-130 meV relative to the main E11 PL emission peaks. Similar satellites, redshifted by 95-145 meV depending on nanotube species, were also found in PL measurements of ensembles of SWNTs in water-surfactant dispersions. The relative intensities of these deep exciton emission features depend on the nanotube surroundings.