Nanowires are a kind of one-dimensional nano materials. The horizontal size of nanowires is less than 100 nanometers, while the vertical size is not limited. With the decrease of diameter, nanowires will show some novel physical properties, including surface effect, quantum confinement effect, small size effect, macroscopic quantum tunneling effect and Coulomb blocking effect. Compared with bulk materials, nanowires have better mechanical properties and unique electrical properties. The special properties of nanowires make them applied in many occasions and have a broad application prospect.
With the unique advantages, nanowires have physical properties that are significantly different from those of bulk materials in magnetic, thermal, optical, electrical and catalytic reactions and the others. Therefore, nanowires have very important applications in the fields of optics and electricity.
- Gas sensor field: Nanowires have high electrical conductivity, large specific surface area, high activity, and are very sensitive to temperature, light, humidity and other changes. Therefore, nanowires are ideal gas-sensitive materials with ultra-high sensitivity. For example, when the gas is adsorbed on the surface of ZnO nanowires, the resistance value will change. Thus, ZnO nanowires can be used as gas sensors.
- Light emitting diode (LED) field: Light emitting diode (LED) is a kind of electroluminescent semiconductor component, which can convert electric energy into light energy. Based on the energy level transition of electrons, light emitting diode (LED) can emit light and the wavelength of the light is determined by the gap width of the material and the energy level of impurity. Nanowires are considered as ideal short wavelength luminescent materials due to their wide band gap and large exciton binding energy.
Figure 1. Light emitting diode (LED) made by Ag nanowires.
- Nanometer laser field: The chemical elasticity and one - dimensional property of nanowires make them an ideal ultra-small laser light source, and it has a wide application prospect in the fields of supercomputer chip, optical fiber communication and bio-sensing.
- The others: In addition to the applications mentioned above, nanowires can be widely used in solar cells, lithium battery anodes, field effect transistors (FET), catalysis and other fields.
Figure 2. An example of perovskite solar cell made by long-term stable silver nanowires.
According to the components, nanowires can be divided into metal nanowires, semiconductor nanowires and molecular nanowires.
- Metal nanowires: Metal nanowires are made of pure metals, mainly including Ni, Pt, Au and the others.
- Semiconductor nanowires: Semiconductor nanowires mainly include InP, Si, GaN, and the others.
- Molecular nanowires: Molecular nanowires are composed of repeating molecules that can be organic or inorganic molecules.
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- Guan N, Dai X, Babichev A, et al. Flexible inorganic light emitting diodes based on semiconductor nanowires[J]. Chemical ence, 2017:7904-7911.
- Jin Y, Sun Y, Wang K, et al. Long-term stable silver nanowire transparent composite as bottom electrode for perovskite solar cells[J]. Nano Research, 2018.