Optical limiting properties of single-walled carbon nanotube dispersions in amide solvents

Abstract

ABSTRACT Single-walled carbon nanotube (SWNT) dispersions were prepared in N -methyl-2-pyrrolidone (NMP), N,N -dimethylformamide (DMF), and N,N -dimethylacetamide (DMA), respectively. The nonlinear optical properties of SWNT dispersions were studied by using the Z-scan method . The nonlinear extinction coeffi cients increase significantly with increasing SWNT concentration. In the three dispersions, the DMF dispersions show the strongest nonlinear extinction effect. In conjunction with this, the optical limiting performance is also superior for the DMF dispersions. Compared with DMF and DMA, NMP has a much better debu ndling effect for SWNTs, ho wever the optical limiting properties of the NMP dispersions is inferior. The static light scattering experiment reveal ed that the DMF dispersions have the largest average bundle size. The principal mechanism of the optical limiti ng effect of the SWNT dispersions is due to the solvent and/or carbon vapour bubble-induced nonlinear scattering. The pr esent results indicate that the average bundle size of SWNTs in combination with the thermodynamical properties of the solvent, dominate the nonlinear extinction and optical limiting prop erties of SWNT dispersions. Keywords: Single-walled carbon nanotubes, optical limiti ng, nonlinear extinction, nonlinear scattering