Defect-Induced Photoluminescence from Dark Excitonic States in Individual Single-Walled Carbon Nanotubes

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• 作者：Hayk Harutyunyan ; Tobias Gokus ; Alexander A. Green ; Mark C. Hersam ; Maria Allegrini ; Achim Hartschuh
• 刊名：Nano Letters
• 出版年：2009
• 出版时间：May 13, 2009
• 年：2009
• 卷：9
• 期：5
• 页码：2010-2014
• 全文大小：182K
• 年卷期：v.9,no.5(May 13, 2009)
• ISSN：1530-6992

文摘

We show that new low-energy photoluminescence (PL) bands can be created in the spectra of semiconducting single-walled carbon nanotubes by intense pulsed excitation. The new bands are attributed to PL from different nominally dark excitons that are “brightened” because of a defect-induced mixing of states with different parity and/or spin. Time-resolved PL studies on single nanotubes reveal a significant reduction of the bright exciton lifetime upon brightening of the dark excitons. The lowest-energy dark state has longer lifetimes and is not in thermal equilibrium with the bright state.