• 文献标题:   Surface oxygen-containing defects of graphene nanosheets with tunable nonlinear optical absorption and refraction
  • 文献类型:   Article
  • 作  者:   ZHU BH, WANG FF, LI P, WANG C, GU YZ
  • 作者关键词:  
  • 出版物名称:   PHYSICAL CHEMISTRY CHEMICAL PHYSICS
  • ISSN:   1463-9076 EI 1463-9084
  • 通讯作者地址:   Henan Univ
  • 被引频次:   6
  • DOI:   10.1039/c8cp04940h
  • 出版年:   2018

▎ 摘  要

Surface oxygen-containing defects of graphene nanosheets (G NSs) are important for the nonlinear optical (NLO) properties in optoelectric devices. G NSs with different surface oxygen-containing defects are successfully tuned by a chemical reduction process, and are characterized by several experimental measurements of morphology and structure and by spectroscopy. Their NLO properties are measured with the Z-scan technique and the NLO transmission method using a 30 picosecond single-pulse laser source at 532 nm wavelength. Their NLO susceptibility is enhanced 11.8 times (from 0.38 x 10(-12) esu to 4.5 x 10(-12) esu) with the decrease in the density of surface oxygen-containing groups, while it is reduced 7.2 times (2.7 x 10(-12) esu) with a further decrease in oxygen. Accordingly, the nonlinear absorption coefficient of graphene is increased from 0.51 cm GW(-1) to 5.90 cm GW(-1), and then decreased to 3.41 cm GW(-1), indicating that the NLO response of graphene NSs should be weakened whether the component of surface oxygen-containing groups is too large or too small. The local field effect arising from surface oxygen-containing groups and isolated sp(2) clusters is the dominant mechanism for the NLO improvement, while the connection of small sp(2) clusters depresses the optical nonlinearity. An evolution from two-photon absorption to saturable absorption with the decrease of surface oxygen concentration is obtained. The intensity-related NLO absorption and refraction in NSs are also discussed. Tuning the surface oxygen-containing defects of graphene is a useful way to enhance the optical nonlinearity for potential applications in devices.