Method and device for chirality assignment of carbon nanotubes
A method for assigning chirality of carbon nanotube is provided. Firstly, carbon nanotube sample, an optical microscope with a liquid immersion objective and a liquid are provided. Secondly, the carbon nanotube sample is immersed in the liquid. Thirdly, the carbon nanotube sample is illuminated by an incident beam to generate resonance Rayleigh scattering. Forthly, the liquid immersion objective is immersed into the liquid to get a resonance Rayleigh scattering (RRS) image of the carbon nanotube sample. Fifthly, spectra of the carbon nanotube sample are measured to obtain chirality of the carbon nanotube sample.
1. A method for assigning chiralities of carbon nanotubes comprising steps of:
S 1 , providing a carbon nanotube sample, an optical microscope with a liquid immersion objective, and a liquid; the carbon nanotube sample comprises carbon nanotubes horizontally aligned on a substrate, and the carbon nanotubes are parallel to each other; and the substrate is a Si substrate coated with a SiO 2 layer, the substrate has a thickness of 500 nanometers, and the SiO 2 layer has a thickness of 100 nanometers; and the liquid is water, and the liquid immersion objective is water liquid immersion;
S 2 , immersing the carbon nanotube sample in the liquid; and the water is held in a container, and the container comprises a side surface and a bottom surface, an angle between the side surface and the bottom surface can range from 45 degrees to 90 degrees; and the substrate is located on the bottom surface and immersed into the water, and the side surface is a planar quartz window;
S 3 , illuminating the carbon nanotube sample by an incident light beam to generate resonance Rayleigh scattering;
S 4 , immersing the liquid immersion objective into the liquid to get a resonance Rayleigh scattering (RRS) image of the carbon nanotube sample; and
S 5 , measuring spectra of the carbon nanotube sample to obtain a chirality of the carbon nanotube sample.
2. The method as claimed in claim 1 , wherein in step S 3 , and the incident beam is set vertical to the side surface and illuminates to the carbon nanotube sample through the side surface.
3. The method as claimed in claim 2 , wherein the incident beam is a white light with a continuous spectrum.
4. The method as claimed in claim 3 , wherein the incident beam is filtered and focused before reaching the carbon nanotube sample.
5. The method as claimed in claim 1 , wherein in step S 4 , a camera is connected to the optical microscope to record the RRS image of the carbon nanotube sample.
6. The method as claimed in claim 1 , wherein in step S 5 , spectral information of the carbon nanotube samples are obtained by a spectrometer.
7. The method as claimed in claim 6 , wherein the spectral information is Rayleigh scattering spectra, Raman scattering spectra, or fluorescence spectral information.
8. The method as claimed in claim 6 , wherein in step S 5 , the Rayleigh scattering spectra and the Raman scattering spectra of the carbon nanotube sample are measured to obtain chiral indices of the carbon nanotube sample.
9. The method as claimed in claim 8 , wherein the Raman scattering spectra of the carbon nanotube sample is obtained on the basis of the Rayleigh scattering spectra of the carbon nanotube sample comprises steps of:
S 51 , measuring resonance Rayleigh scattering spectra of the carbon nanotube sample;
S 52 , selecting excitation wavelength needed to produce Raman scattering by Rayleigh scattering spectra of the carbon nanotube sample; and
S 53 , obtaining the Raman scattering of the carbon nanotube sample.
10. The method as claimed in claim 9 , wherein the Raman spectra of the carbon nanotube sample is excited by a light source.
11. The method as claimed in claim 1 , wherein the incident beam is a white light with a continuous spectrum.