Charge transfer equilibria between diamond and an aqueous oxygen electrochemical redox couple
Charge transfer equilibria between diamond and an aqueous oxygen electrochemical redox couple
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DOI：
10.1126/science.1148841
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发表时间：
2007-11-30
期刊：
影响因子：
56.9
通讯作者：
Sumanasekera, Gamini U.
中科院分区：
文献类型：
--
作者：
Chakrapani, Vidhya;Angus, John C.;Sumanasekera, Gamini U.
在几乎所有情况下，未掺杂的高质量钻石都是已知的最好的绝缘体之一。然而，覆盖着化学结合氢的钻石在暴露在空气中时显示出显著的导电性。这种导电性来自正电荷载流子(空穴)，并且被限制在狭窄的近表面区域。尽管已经提出了几种解释，但都没有得到广泛的接受，而且这种机制仍然存在争议。在这里，我们报告了氢端接的宏观钻石和钻石粉末与控制pH值和氧气浓度的水溶液的相互作用。我们证明了电子在金刚石和含氧的电化学还原/氧化对之间的转移。这种电荷转移是表面导电性的原因，也影响接触角和Zeta电位。这种影响不仅限于钻石，还可能在其他不同的系统中发挥以前未被认识到的作用。
Undoped, high-quality diamond is, under almost all circumstances, one of the best insulators known. However, diamond covered with chemically bound hydrogen shows a pronounced conductivity when exposed to air. This conductivity arises from positive-charge carriers ( holes) and is confined to a narrow near-surface region. Although several explanations have been proposed, none has received wide acceptance, and the mechanism remains controversial. Here, we report the interactions of hydrogen-terminated, macroscopic diamonds and diamond powders with aqueous solutions of controlled pH and oxygen concentration. We show that electrons transfer between the diamond and an electrochemical reduction/oxidation couple involving oxygen. This charge transfer is responsible for the surface conductivity and also influences contact angles and zeta potentials. The effect is not confined to diamond and may play a previously unrecognized role in other disparate systems.