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The Research on Silicon Based Solar Cells with New Anti-relaction Micro-nano Structures

Author: ZhuJun
Tutor: DingJianNing
School: Jiangsu University
Course: Mechanical and Electronic Engineering
Keywords: solar cell nanocrystalline silicon thin film silicon nanowires femtosecondlaser anti-relation optical model the optical band gap the gradient bandgap graphene titanium dioxide
CLC: TM914.4
Type: PhD thesis
Year: 2014
Downloads: 12
Quote: 0
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Abstract

With the progress of the thin film technology and the development of micro-Nano manufacturing technology, a new type of micro-Nano silicon thin film solar cells is created by incorporating the two technologies in silicon solar cells.In recent years, high-profile hydrogenated silicon thin film solar cells gradually become the focus of research. By controlling the technology conditions the band gap size adjustment can be realized, so as to adjust the available spectral response range. In this paper, by employing nanocrystalline silicon films and micro-nano anti-reflection structure design, a new micro-nano silicon-based solar cells with anti-reflection structure is investigated. The experimental and simulation results show that the following conclusions can be drawn.By researching the growth mechanism of nanocrystalline silicon thin film, after a great deal of experiments of nanocrystalline silicon thin film preparation, we preliminarily obtained that the thin film deposition, silane concentration, deposition rate, RF power, DC bias and substrate temperature, reaction chamber pressure, the size of the prepared nanocrystalline silicon thin film, and the inner relation of thin film optical band gap. By conducting a lot of experiments, some conclusions can be drawn. When nanocrystalline silicon film is doped, the radio frequency power, DC bias, substrate temperature and the reaction chamber pressure have an impact on the produced good p-type nanocrystalline silicon thin film and n-type nanocrystalline silicon thin film. By using the AMPS-1D software to simulate the thin film optical band gap, the front barrier height Φ B0, interface layer defect mode, intrinsic layer thickness and intrinsic defect density, the corresponding performance parameters are presented, which provides reference for preparation of high performance battery.The light effect of micro-nano structure is theoretically elaborated, and the related optical geometry research model is established. By simulating the light structure of nanowires or nanopores with OptiFDTD V8.0software, the structural optimization parameters of the width, adjacent distance and depth of the nanowires or nanopores can be obtained, which can provide theoretical foundation for manufacturing miconano silicon solar cells with anti-reflection structure. In using the femtosecond laser ablation method, femtosecond laser power must be controled, which can’t exceed crystal phase and amorphous phase plasma gasification threshold, otherwise there will be a breakdown of the ablation phenomenon.In this paper, the anti-reflection mechanism of nanocomposite film has been explored. When the photon light is projected on the metal nanoparticles, an extra nuclear electron cloud is produced on the surface of metal nanoparticles, Metal nanoparticles oscillate to produce localized surface plasmons, which interacted with the photons to produce a scattering under the appropriate conditions.The two kinds of graphene film composite film have been investigated and prepared. The first one can not only form a composite electrode, but also increase carrier collection ability as a decreased layer by increasing the TiO2nanoparticles on graphene film coating. The second one can be formed Ag NPs/RGO composite film by increasing the Nano size silver particles in the graphene films, which can be used as both electrode and decreased layer. Study of the performance characteristics of two kinds of composite electrode shows that the two kinds of electrodes have excellent electrical properties and optical properties, which provides basis for the preparation of micro-Nano anti-reflection structure silicon cells.Two novel micro-Nano silicon solar cells with anti-reflection structure are produced. They are micro-Nano silicon nanowires solar cell with anti-reflection structure and nanometer silicon gradient band gap solar cell based on composite graphene film. Two kinds of nanometer silicon thin-film solar cells based on graphene electrode gradient band gap have been prepared and investigated in details. One kind is the gradient band gap solar cell with decrease layer of TiO2. The other is the gradient of the band gap decreased layer solar cells with deposition silver nanoparticles in graphene. The cells with TiO2as decrease layers has efficiency of4.97%, while the other is4.59%. If there isn’t reflect layer, it is called bare solar cell. Its efficiency is2.82%. Such efficiency is mainly because when nanocrystalline silicon thin film is deposited, the surface of the thin film deposition is uneven, thus graphene is unable to fully contact with the surface of silicon thin film when graphene films is coated on the silicon thin film surface. This affects the collection ability of carrier and reduces the value of the short circuit current and open circuit voltage, and thus solar cell fill factor is also affected. In addition, when grapheme is lifted, the nonuniform thickness of graphene film will affect the incoming light and effective number of photons. After testing, the solar cell performance with anti-reflection layer is significantly better than no anti-reflection layer solar cell.

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CLC: > Industrial Technology > Electrotechnical > Independent power supply technology (direct power) > Photocell > Solar cells
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