Semiconductor carbon nanotubes

Carbon nanotubes are round tubes wound by graphite layers. This winding changes the shape of the p electron cloud in the graphite layer, and this change is related to the diameter of the formed carbon nanotubes. The smaller the diameter, the greater the curvature, and the greater the change in the shape of the p electron cloud. On the contrary, the larger the diameter of the carbon nanotube, the smaller the curvature, the closer the p electron cloud is to the case of graphite, and thus its properties are close to graphite. ...

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Carbon nanotubes are coaxial hollow seamless tubular structures formed by curling single-layer or multi-layer graphene sheets around the center at a certain angle. The tube wall is mostly composed of hexagonal carbon atom grids.

According to the number of tube wall layers, they are generally divided into single-layer carbon nanotubes and multi-layer carbon nanotubes:

Single-walled carbon nanotubes (SWNTs): composed of a layer of graphene sheets. The typical diameter and length of single-walled tubes are 0.75~3nm and 1~50μm respectively.

Multi-walled carbon nanotubes (MWNTs): Contains multiple layers of graphene sheets. The shape is like a coaxial cable. The number of layers ranges from 2 to 50, and the interlayer spacing is 0.34±0.01nm, which is equivalent to the interlayer spacing of graphite (0.34nm). The typical diameter and length of multi-walled tubes are 2~30nm and 0.1~50μm respectively.

Because carbon nanotubes have a more stable structure than graphite, they can be formed under certain conditions.

Carbon nanotubes are round tubes wound by graphite layers. This winding changes the shape of the p electron cloud in the graphite layer, and this change is related to the diameter of the formed carbon nanotubes. The smaller the diameter, the greater the curvature, and the greater the change in the shape of the p electron cloud. On the contrary, the larger the diameter of the carbon nanotube, the smaller the curvature, the closer the p electron cloud is to the case of graphite, and thus its properties are close to graphite.

What is the minimum diameter of carbon nanotubes?

The properties of carbon nanotubes depend largely on diameter and chirality. The smaller the diameter, the greater the difference between the state of the electron and sp2, and the more obvious the quantum effect.

For semiconductor carbon nanotubes, the bandgap width is inversely proportional to the tube diameter, and has nothing to do with chirality.

Carbon nanotubes can be used in a variety of plastics such as PE, PP, PS, ABS, PVC, PA, as well as rubber, resin, and composite materials. They can be evenly dispersed in the matrix, giving the matrix excellent conductive properties.

Widely used in the following industries:

Films, various plastic products

Antistatic packaging

Packaging, transmission, and processing materials for electronic devices

Conductive rubber rollers, transmission belts, seals

Automotive industry

Power cables and accessories

Conductive coatings

Film reels

Electromagnetic shielding, military fields

The amount of carbon nanotubes added is only one-third to one-fifth of that of conductive carbon black, and the same conductivity can be achieved. Excessive addition of conductive fillers will not cause loss of plastic mechanical properties.

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