In order to study the properties of single carbon nanotubes and device performance, as well as the manipulation of carbon nanotubes to get a special structure, people often need to locate a carbon nanotube under optical microscope in order to conduct spectral characterization and device construction. The traditional method of using scanning electron microscopy to mark the location is more complicated and easy to pollute the carbon nanotubes. Optically visible nano-materials to meet people's needs. However, the existing methods of depositing metal or oxide nanoparticles on the surfaces of carbon nanotubes, although visible under an optical microscope, may lead to the degradation of the properties of the carbon nanotubes and are not conducive to the exploration of the intrinsic physical properties of the carbon nanotubes.

The excellent properties of carbon nanotubes are easily influenced by the surrounding environment. In the past, the mixed samples were used to study the physical properties of carbon nanotubes. The average information of various structures in samples was often obtained, but the structure and physical properties of carbon nanotubes Relationship. Therefore, characterization of the intrinsic physical properties of single carbon nanotubes has been the forefront of researchers to explore. For example, in the light absorption detection of carbon nanotubes, with the development of the CCD technology and the improvement of the laser intensity, it is no longer hard to solve the problem of detecting the minute optical signal. However, while detecting and amplifying the optical signal of a single carbon nanotube sample, it is still difficult to eliminate the influence of the substrate and the surrounding environment. In the thermal properties of carbon nanotubes, theoretical studies have shown that carbon nanotubes have very high thermal conductivity, but due to different measurement methods, coupled with the use of the sample of varying quality and uneven structure, the experiment measured carbon The thermal conductivity of nanotubes varies greatly. In addition to the structural characterization of carbon nanotubes, the use of non-contact measurement of nanomaterials temperature is also a problem that must be addressed.

Institute of Physics, Chinese Academy of Sciences, Beijing Institute of Advanced Materials and Structure Analysis, National Institute of Condensed Matter Physics (A05 Group), has been devoted to the preparation of carbon nanotubes, physical properties And Applied Research. On the basis of previous work, Zhang Xiao et al., A doctoral student with deep thinking of Chinese Academy of Sciences, developed a reversible, long-lasting and nondestructive method to detect the optical visible and intrinsic physical properties of a single suspended single-walled carbon nanotube (China Invention Patent, Application No..7,.5) Recently, Professor Song Li from University of Science and Technology of China, Researcher Bai Xuedong from Institute of Physics SF1, Dr. Xuexian Tian, ​​Ph.D. from National Nanoscience Center, Significant advances have been made in the optical visualization of carbon nanotubes and their intrinsic optical and thermal properties.

Based on partially vacant long carbon nanotubes, the configuration of nanometer-sized carbon nanotubes is visible under a light microscope by forming a micro-diameter heterogeneous shell structure of ice-carbon nanotubes. By using different polarization lasers to irradiate the heteroshell structure, the problem of light absorption section of a single carbon nanotube has been studied systematically according to the disappearance of different ice layers and the chirality of the carbon nanotubes determined by electron diffraction. Based on the laser-induced partial melting phenomenon, a one-dimensional steady-state heat conduction equation is established. By using the Raman G-mode redshift of carbon nanotubes, the temperature of the edge of the laser spot and the ice , The axial thermal conductivity of the super-long-dangling carbon nanotubes with different chirality is calculated in the range of 2000-6000 W K-1 m-1, which is close to the theoretical calculation value. Relevant findings are published on (NPG) Light: Science & Applications (2015, 4, e318; DOI: 10.1038 / lsa.2015.91).

The work has been the Ministry of Science and Technology, the National Natural Science Foundation and the Chinese Academy of Sciences and other projects support.

Fig. 1 (left panel a, b) Partially suspended ultra-long carbon nanotube sample as carbon nanotube structure-property test platform; (Right) Carbon nanotube structure and chiral characterization at narrow slit: (a) HRTEM image , (C) electron diffraction patterns and (b) theoretical simulation results.

Fig. 2 (a) Sketch of melting of surface ice layer by laser heating of carbon nanotubes; (bd) Different polarized laser lead to local disappearance of surface ice layer.

Figure 3 The axial thermal conductivity of multiple discrete carbon nanotubes calculated using the one-dimensional steady-state heat conduction equation.

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