• 文献标题:   Electronics and Optics of Graphene Nanoflakes: Edge Functionalization and Structural Distortions
  • 文献类型:   Article
  • 作  者:   COCCHI C, PREZZI D, RUINI A, CALDAS MJ, MOLINARI E
  • 作者关键词:  
  • 出版物名称:   JOURNAL OF PHYSICAL CHEMISTRY C
  • ISSN:   1932-7447
  • 通讯作者地址:   CNR Ist Nanosci
  • 被引频次:   33
  • DOI:   10.1021/jp300657k
  • 出版年:   2012

▎ 摘  要

The effects of edge covalent functionalization on the structural, electronic, and optical properties of elongated armchair graphene nanoflakes (AGNFs) are analyzed in detail for a wide range of terminations, within the framework of Hartree-Fock-based semiempirical methods. The chemical features of the functional groups, their distribution, and the resulting system symmetry are identified as the key factors that determine the modification of strutural and optoelectronic features. While the electronic gap is always reduced in the presence of substituents, functionalization-induced distortions contribute to the observed lowering by about 35-55% This effect is paired with a red shift of the first optical peak, corresponding to about 75% of the total optical gap reduction. Further, the functionalization pattern and the specific features of the edge-substituent bond are found to influence the strength and the character of the low-energy excitations. All of these effects are discussed for flakes of different widths, representing the three families of AGNFs.