Quantum yield heterogeneities of aqueous single-wall carbon nanotube suspensions
Quantum yield heterogeneities of aqueous single-wall carbon nanotube suspensions
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DOI：
10.1021/ja071553d
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发表时间：
2007-07-04
影响因子：
15
通讯作者：
Hertel, Tobias
中科院分区：
文献类型：
--
作者：
Crochet, Jared;Clemens, Michael;Hertel, Tobias
单壁碳纳米管（SWNTs）的水悬浮液制备的超浓缩胶束SWNT混合物的上清液通过传统的方法被证明是强烈的异质性相对于其成分的量子产率。的异质性使用制备ultracentrination碘克沙醇密度梯度分离，并通过光致发光和线性吸收光谱的光学特征。我们发现，具有1.055 +/- 0.005 g中心点cm（-3）的密度的最浮力部分具有1.1%的最高光致发光量子产率η，比上清液高5倍。具有较低η的较致密部分占这些样品的约（2）/（3），并且主要包含小绳，其中量子产率通过耦合到金属管的非辐射衰变而降低。
Aqueous suspensions of single-wall carbon nanotubes (SWNTs) prepared by traditional methods from the supernatant of ultracentrifuged micellar SWNT mixtures are shown to be strongly heterogeneous with respect to the quantum yield of their constituents. The heterogeneities are isolated using preparative ultracentrifugation in iodixanol density gradients and are optically characterized by photoluminescence and linear absorption spectroscopy. We find that the most buoyant fractions with a density of 1.055 +/- 0.005 g center dot cm(-3) have the highest photoluminescence quantum yield eta of 1.1%, a factor of 5 higher than that of the supernatant. Denser fractions with lower eta make up for about (2)/(3) of these samples and contain mostly small ropes in which the quantum yield is reduced by nonradiative decay through coupling to metallic tubes.