【作者】 祝俊；

【导师】 丁建宁；

【作者基本信息】 江苏大学 ， 机械电子工程， 2014， 博士

【摘要】 随着薄膜技术的进步和微纳制造技术的发展,可把薄膜技术、微纳制造技术与硅基太阳能电池结合,形成新型微纳结构的硅基薄膜太阳能电池。近年来,氢化纳米晶硅薄膜太阳能电池备受瞩目,逐渐成为研究的热点。通过控制工艺条件,可实现带隙大小调节,从而调控有效利用光谱的响应范围。论文提出利用纳米晶硅薄膜和设计微纳减反结构,研究新型微纳减反结构的硅基太阳能电池。通过大量的实验和仿真研究得到以下结论：一、通过对纳米晶硅薄膜生长机理的研究,经过大量的纳米晶硅薄膜制备实验,初步得到了薄膜沉积时硅烷浓度、沉积速率、射频功率、直流偏压、衬底温度、反应室压强对所制备纳米晶硅薄膜晶粒的尺寸、以及薄膜光学带隙存在的内在关系；通过大量的掺杂实验,得到了本征纳米晶硅掺硼和掺磷时,射频功率、直流偏压、衬底温度、反应室压强等对生成P型纳米晶硅薄膜和N型纳米晶硅薄膜的性能影响；采用AMPS一1D软件对薄膜光学带隙、前端势垒高度①B0、界面层缺陷态、本征层厚度和本征层缺陷态密度进行了仿真,给出了相应的仿真参数,为高性能电池制备工艺的制定提供参考。二、从理论上阐述了微纳结构的减反效应,并建立了相关光学几何研究模型。采用OptiFDTD.V8.0软件对纳米线或纳米孔减反结构进行了仿真,给出了对应的纳米线或纳米孔的宽度、相邻的间距和深度等优化的结构参数,为制备纳米硅线减反层提供理论支撑；通过化学刻蚀的方法制备并表征了体硅纳米线,在采用飞秒激光烧蚀法纳米硅薄膜制备薄膜纳米线时,需控制飞秒激光的功率不能超过晶相和非晶相的等离子气化阈值,否则会出现烧蚀击穿现象。三、探明了纳米复合薄膜减反射的机理。纳米金属粒子对入射光线产生核外电子云,并发生振荡,产生局域表面等离子激元,等离子激元与光子相互作用,在适当条件下可以产生前散射,进而起到减反射的作用。四、制备出两种石墨烯复合薄膜。一是,在石墨烯薄膜上增加TiO2纳米颗粒涂层,形成复合薄膜,其既可以作为电极增加收集载流子能力,又可以作为减反层。二是,在石墨烯薄膜中添加纳米银颗粒,形成Ag/NPs/RGO复合薄膜,既可以作为电极,也可以作为减反层。通过对两种复合薄膜进行了性能表征,发现这两种电极具有优异的电学性能和光学性能,为制备微纳减反结构的纳米硅基电池提供依据。五、制备出两种新型微纳减反结构的硅基太阳能电池：硅纳米线微纳减反结构电池和基于石墨烯复合薄膜的纳米硅基渐变带隙电池。其中,石墨烯复合薄膜的纳米硅基渐变带隙电池,因采用两种不同结构的石墨烯复合薄膜作为减反层,从而形成了不同结构的纳米硅基渐变带隙薄膜电池：采用二氧化钛为减反层的渐变带隙电池和采用石墨烯中沉积纳米银颗粒为减反层的渐变带隙电池。以二氧化钛复合薄膜为减反层的电池效率为4.97%左右,以纳米银颗粒复合薄膜为减反层的电池效率为4.59%,高于没有采用减反层的“基体”电池效率2.82%。分析了影响这些电池效率的主要因素：在沉积纳米硅薄膜时,薄膜沉积的表面不是很平整,导致在涂石墨烯复合薄膜时,难以做到石墨烯与硅薄膜表面很好结合,影响了载流子的收集,降低了短路电流和开路电压,其填充因子也受到很大制约。此外,还有石墨烯在提拉的过程中,薄膜厚度不均匀也会影响入射光线,进而影响吸收有效的光子数量。在硅纳米线微纳减反电池中,经检测有减反层的电池性能明显优于没有减反层的电池性能。更多还原

【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.更多还原