Extrinsic and Intrinsic Effects on the Excited-State Kinetics of Single-Walled Carbon Nanotubes

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• 作者：Marcus Jones ; Wyatt K. Metzger ; Timothy J. McDonald ; Chaiwat Engtrakul ; Randy J. Ellingson ; Garry Rumbles ; Michael J. Heben
• 刊名：Nano Letters
• 出版年：2007
• 出版时间：February 2007
• 年：2007
• 卷：7
• 期：2
• 页码：300 - 306
• 全文大小：297K
• 年卷期：v.7,no.2(February 2007)
• ISSN：1530-6992

文摘

We characterized the photoluminescence (PL) decay of 15 different, solubilized single-walled carbon nanotubes with tube diameters thatranged from 0.7 to 1.1 nm using time-correlated single photon counting. Each nanotube species was excited resonantly at the second excitedstate, E₂, and PL was detected at the lowest energy exciton emission, E₁. In a 10 ns window, the PL decays were described well by abiexponential fitting function with two characteristic time constants, suggesting that at least two kinetically distinct relaxation processes wereobserved. The dominant decay component increased from 60 to 200 ps with increasing tube diameter, while the lesser component, whichcontributed up to 8% of the total decay, increased from 200 ps to 4.8 ns. The observation of the second, longer decay time component isexamined in terms of two possible models: an extrinsic behavior that implicates sample inhomogeneity and an intrinsic process associatedwith interconversion between kinetically distinct bright and dark exciton states. A common conclusion from both models is that nonradiativedecay controls the PL decay by a process that is diameter dependent.