Measurement Of Chiral Single-Walled Carbon Nanotubes

Single-walled carbon nanotubes have unique structures, specialphysical and chemical properties. The single-walled carbon nanotubesproduced are a mixture of single-walled carbon nanotubes with differentchirality, diameters and lengths, which leads directly to the differentelectrical properties and hinders their application of single-walled carbonnanotubes in the area of materials. Therefore, the preparation, purificationand structural characterization of single-walled carbon nanotubes become ahot topic of nanomaterials research. Measurement of chiral single-walledcarbon nanotubes is of great significance to the application of carbonnanomaterials. In this work, the chiral separation and chiral measurement ofsingle-walled carbon nanotubes have been studied by Raman spectra,Raman frequency shift calibration, and Raman spectral intensity calibration.The main results were as follwes:1. The amorphous carbon, carbon nanoparticles and metal catalystimpurities mixing with single-walled carbon nanotubes can be removed bychiral separation, which can eliminate some influence over thecharacterization of single-walled carbon nanotubesthe. The single-walled carbon nanotubes according to different electrical conductivity and differentlength were separated by the gel column separation method. Thesingle-walled carbon nanotubes separated were characterized by scanningelectron microscopy and Raman spectroscopy. The experimental conditionsof sample concentration, ultrasonic time, the gel column length, injectionvolume, flow rate of mobile phase, eluent concentration which have mucheffect on the dispersion and separation of single-walled carbon nanotubeswere optimized. The separation mechanism was discussed. Themetal-enhanced single-walled carbon nanotubes in the length range of1.8μm~800nm and semiconductor-enhanced single-walled carbon nanotubesfrom800nm to1.4μm were obtained.2. Single-walled carbon nanotubes radial breathing modes (RBM) hasmeasured by the Raman spectra. The spiral index (n, m), chiral angle,diameter, conductivity and other parameters of single-walled carbonnanotubes were calculated by RBM values and kataura plot data. Formeasuring the same single-walled carbon nanotube ample under differentlaser wavelengths, the results showed that different hand spiral indexs wereobtained:488nm (7,4),632.8nm (7,5), and785nm (11,3) respectively.3. The pure sulfur and naphthalene were used to calibrate thefrequency shift of Raman spectroscopy respectively. The results showed thatthe measurement error of the Raman spectra in the low-frequency shift wasslightly lower than one in the high-frequency shift. The low-frequency shift calibration of the Raman spectra could meet the measurement accuracy ofchiral single-walled carbon.4. ZnO-B2O3-SiO2(ZBS) glass was synthesized by solid statesynthesis method. Structure and spectral property of prepared ZBS glasssamples were investigated by XRD, FL and Raman. By adding Ba, Ti in theglass, the Raman intensity of the zinc borosilicate glass can be controlledwhen the frequency shift ranges from the500cm-1to3000cm-1, which canmeet the demand of the reference substances for the Raman spectralintensity calibration during the measurement of chiral single-walled carbonnanotubes.