Graphene Dispersion and Exfoliation in Low Boiling Point Solvents
Graphene Dispersion and Exfoliation in Low Boiling Point Solvents
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DOI：
10.1021/jp110942e
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发表时间：
2011-04-07
影响因子：
3.7
通讯作者：
Coleman, Jonathan N.
中科院分区：
文献类型：
--
作者：
O'Neill, Arlene;Khan, Umar;Coleman, Jonathan N.
石墨烯的溶剂剥离的问题之一是，最好的溶剂往往具有高沸点，因此很难去除，可能会出现片状沉积和复合材料形成的问题。在这里，我们展示了石墨烯在相对较高浓度的低沸点溶剂如氯仿和异丙醇中的剥离。可以达到高达0.5毫克/毫升的浓度，略低于N-甲基吡咯烷酮等高沸点溶剂浓度的一半。这些分散体由长度类似1微米、厚度小于10层(75%的石墨烯仍无限期分散)的石墨烯薄片组成。拉曼光谱显示，这些薄片相对没有缺陷。低沸点溶剂的一个显著优点是，它们允许将单个薄片喷雾浇注到基材上。可控地获得了每10亩米×10亩平方米的长度为1微米的薄片的沉积密度。虽然观察到了一些在基质上的聚集，但这比从高沸点溶剂喷雾时要少得多。
One of the problems with solvent exfoliation of graphene is that the best solvents tend to have high boiling points and so are difficult to remove and can present problems for flake deposition and composite formation. Here, we demonstrate the exfoliation of graphene at relatively high concentration in low boiling point solvents such as chloroform and isopropanol. It is possible to achieve concentrations of up to 0.5 mg/mL, just under half that which can be achieved with high boiling point solvents such as N-methyl-pyrrolidone. These dispersions consist of graphene flakes of similar to 1 mu m length and with a thickness of less than 10 layers ( 75% of the graphene remains dispersed indefinitely. Raman spectroscopy shows the flakes to be relatively defect-free. A significant advantage of low boiling point solvents is that they allow individual flakes to be spray cast onto substrates. Deposited densities of > 10 flakes with length > 1 mu m per 10 mu m x 10 mu m square have been controllably achieved. While some on-substrate aggregation is observed, this is much less prevalent than when spraying from high boiling point solvents.