| The silicon solar cell is one of the important photovoltaic devices in the world. Now the main research direction of the solar cell is to improve its efficiency. With the development of nano materials, it is found that solar cells could be enhanced by using great properties of mechanics, electronics and optics from nano materials. Here we studied in several nano materials and their applications in silicon solar cells, which aim to decrease the reflection light, reduce the loss of series resistance connection, improve the surface and bulk passivation, lower the surface composition, etc. Furthermore, in order to apply carbon atom chains and graphene nano plates to solar cells, we also calculated several properties of them.First, we synthesized the single carbon nanotubes(SWNTs) by arc charging method and analysized its properties. After that we coated SWNTs upon the solar cell as a net layer. It is found that the efficiency of solar cells has been largely enhanced. The value of enhancement is related with the density of SWNTs and homodisperse on the cells. The efficiency and short current of solar cells is improved up to 3.92% and 1.71% respectively when the base density of SWNTs reaches to 360 tube/μm2. The enhancement comes from the high conductivity and light absorption. The high conductivity reduced the surface resistance, and light trapping property of the net structure decrease the light reflection. Furthermore, SWNTs can generate excitonic effect, which increase the availability of incident light.Because of the high conductivity and stablity of Ni nanowires, we quoted a new synthesize method for Ni nanowires, which got the high quality products with magnetism. Spin coated Ni nanowires onto solar cells as net layers. The experiment data confirms that Ni nanowires are also fit for solar cells enhancement. When the density of Ni nanowires reaches to 200 mg/m2, it offers an improvement of 0.75% and a decrease of 5Ω/sq to the efficiency and surface resistant of solar cells, respectively. Comparing with SWNTs, the Ni nanowires owns good conductivity. However, it also owns many defects which could reduce the efficiency of solar cells.We applied(ZnO:Al) film(AZO film) to the solar cell by using radio frequency sputtering, which was combined with the SiNx layer as a new anti-reflection layer. The result demonstrates that AZO film can enhance the capability of silicon solar cells. When the thickness of AZO film reached to 100 nm, the efficiency of the solar cell would increase up to 0.67%, and the fill factor would increase up to 3.16%. Now the research shows that the combination layer works as an anti-reflection layer, which decreases the light reflection, increases the conductivity and reduces the series resistance, which enhances the solar cell.In this paper the graphene nano plate was calculated theoretically through first principle theory, and analyzed the relation between properties and area. The result shows that the energy band gap is decreasing with the increase of area, and the specific heat capacity is reducing with the increase of area at room temperature. Calculation of defect graphene also confirms the important effect of area towards properties. High percentage of defect leads great effect. We also calculated the carbon atom chain through first principle theory and obtained some properties in electronics, mechanics and thermotics. They demonstrate that polyyne, one kind of one dimensional carbon atom chain, has extremely young’s modulus(1304.19 GPa), and has metallic property. Cumulene, another kind of one dimensional carbon atom chain, has semi conductor property(1.859 eV) and high young’s modulus. Both of them have good application prospect. Carbon atom chains doped with S also own great properties. Comparing with standard carbon atom chain, it can be found that S atoms have deeply affected the properties. All the calculations show that grapheme nano plates and carbon atom chains have great semi-conductor property, which can be applied to photovoltaic devices and electronic devices. |
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