Nonlinear photoluminescence imaging of isotropic and liquid crystalline dispersions of graphene oxide

ACS Nano. 2012 Sep 25;6(9):8060-6. doi: 10.1021/nn302644r. Epub 2012 Aug 27.

Abstract

We report a visible-range nonlinear photoluminescence (PL) from graphene oxide (GO) flakes excited by near-infrared femtosecond laser light. PL intensity has nonlinear dependence on the laser power, implying a multiphoton excitation process, and also strongly depends on a linear polarization orientation of excitation light, being at maximum when it is parallel to flakes. We show that PL can be used for a fully three-dimensional label-free imaging of isotropic, nematic, and lamellar liquid crystalline dispersions of GO flakes in water. This nonlinear PL is of interest for applications in direct label-free imaging of composite materials and study of orientational ordering in mesomorphic phases formed by these flakes, as well as in biomedical and sensing applications utilizing GO.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Anisotropy
  • Graphite / chemistry*
  • Lasers*
  • Liquid Crystals / analysis
  • Liquid Crystals / chemistry*
  • Luminescent Measurements / methods*
  • Materials Testing / methods
  • Nanostructures / chemistry*
  • Nanostructures / ultrastructure*
  • Nonlinear Dynamics
  • Oxides / chemistry
  • Particle Size

Substances

  • Oxides
  • Graphite