State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, People's Republic of China.
Nanotechnology. 2010 Feb 10;21(6):065201. doi: 10.1088/0957-4484/21/6/065201. Epub 2010 Jan 8.
Using density functional theory and nonequilibrium Green's function (NEGF) formalism, we have theoretically investigated the binding of organic donor, acceptor and metal atoms on graphene sheets, and revealed the effects of the different noncovalent functionalizations on the electronic structure and transport properties of graphene. The adsorptions of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and tetrathiafulvalene (TTF) induce hybridization between the molecular levels and the graphene valence bands, and transform the zero-gap semiconducting graphene into a metallic graphene. However, the current versus voltage (I-V) simulation indicates that the noncovalent modifications by organic molecules are not sufficient to significantly alter the transport property of the graphene for sensing applications. We found that the molecule/graphene interaction could be dramatically enhanced by introducing metal atoms to construct molecule/metal/graphene sandwich structures. A chemical sensor based on iron modified graphene shows a sensitivity two orders of magnitude higher than that of pristine graphene. The results of this work could help to design novel graphene-based sensing or switching devices.
我们运用密度泛函理论和非平衡格林函数（NEGF）方法，从理论上研究了有机给体、受体和金属原子在石墨烯片上的结合，并揭示了不同非共价功能化对石墨烯电子结构和输运性质的影响。2,3-二氯-5,6-二氰基-1,4-苯醌（DDQ）和四硫富瓦烯（TTF）的吸附导致分子能级与石墨烯价带之间的杂化，并将零带隙半导体石墨烯转变为金属石墨烯。然而，电流-电压（I-V）模拟表明，对于传感应用，有机分子的非共价修饰不足以显著改变石墨烯的输运性质。我们发现，通过引入金属原子构建分子/金属/石墨烯三明治结构，可以显著增强分子/石墨烯的相互作用。基于铁修饰石墨烯的化学传感器的灵敏度比原始石墨烯高两个数量级。这项工作的结果有助于设计新型基于石墨烯的传感或开关器件。
