Huang Lin, Sk Mahasin Alam, Chen Peng, Lim Kok Hwa
School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 639798 (Singapore).
Chemphyschem. 2014 Aug 25;15(12):2610-7. doi: 10.1002/cphc.201402133. Epub 2014 Jun 12.
Phenyl radical (Ph˙) adsorption on monolayer graphene sheets is used to investigate the band-gap manipulation of graphene through density functional theory. Adsorption of a single Ph˙ on graphene breaks the aromatic π-bond and generates an unpaired electron, which is delocalized to the ortho or para position. Adsorption of a second radical at the ortho or para position saturates the radical by electron pairing and results in semiconducting graphene. Adsorption of a second radical at the ortho position (ortho-ortho pairing) is found to be more favorable than adsorption at the para position (ortho-para pairing), and the ortho-ortho pairing has stronger effects on band-gap opening compared with ortho-para pairing. Adsorption of even numbers of Ph˙ on graphene by ortho-ortho and ortho-para pairings, in general, increases the band gap. Our study shows promise of band-gap manipulation in monolayer graphene by Ph˙ adsorption, leading to potential wider applications of graphene.
通过密度泛函理论，利用苯基自由基（Ph˙）在单层石墨烯片上的吸附来研究石墨烯的带隙调控。单个Ph˙吸附在石墨烯上会破坏芳香π键并产生一个未成对电子，该电子会离域到邻位或对位。在邻位或对位吸附第二个自由基会通过电子配对使自由基饱和，从而产生半导体性的石墨烯。研究发现，在邻位吸附第二个自由基（邻位 - 邻位配对）比在对位吸附（邻位 - 对位配对）更有利，并且与邻位 - 对位配对相比，邻位 - 邻位配对对带隙打开的影响更强。一般来说，通过邻位 - 邻位和邻位 - 对位配对在石墨烯上吸附偶数个Ph˙会增加带隙。我们的研究表明，通过Ph˙吸附来调控单层石墨烯的带隙具有前景，这将使石墨烯有更广泛的潜在应用。
