微晶硅衬底上金属纳米结构光散射特性的数值模拟

发布时间：2018-05-09 06:21

本文选题：表面等离激元 + 数值模拟　；参考：《郑州大学》2015年硕士论文

【摘要】：太阳电池大规模应用应当具备两个条件:一是成本低,二是效率高。微晶硅薄膜太阳电池不仅具有原材料丰富、低温成膜技术成熟、工艺相对简单等特点,而且还能在廉价的衬底上实现大面积的生产,使得微晶硅薄膜太阳电池具有低成本优势,但是其较薄的光吸收层降低了光吸收,进而使得微晶硅薄膜太阳电池光电转换效率偏低。在当前光伏领域,利用金属纳米颗粒表面等离激元陷光技术来提高薄膜太阳电池的光吸收效率引起了广泛的关注。本学位论文首先综述了太阳电池光管理技术,并重点介绍了金属纳米颗粒表面等离激元在太阳电池中的应用,然后,采用基于有限元法(FEM)的COMSOL数值模拟软件研究了金属纳米颗粒以及核壳纳米结构的光散射特性,最后,为微晶硅薄膜太阳电池设计出了宽光谱陷光结构。得到的主要结论如下:1、金属纳米颗粒光散射特性研究:模拟并计算了不同尺寸的球状纳米颗粒的光散射性能,结果表明:与Au、Cu相比,Ag和Al纳米颗粒具备高散射,低吸收的特点。作为散射中心,球状纳米颗粒的半径在100 nm左右为宜,与球状纳米颗粒相比,半球状和圆柱状纳米颗粒的耦合效率较高,但其散射截面偏低。2、核壳纳米结构光散射特性研究:Al@Al2O3核壳结构中很薄的氧化层(2 nm)对金属核壳纳米颗粒光散射性能影响很小;相同尺寸下,Al@Ag核壳结构比Al的光散射性能更优;Si O2@Ag核壳结构的性能很大程度上受到壳层厚度以及壳层材料的影响。3、微晶硅薄膜太阳电池宽光谱陷光结构的设计:在微晶硅薄膜太阳电池前表面设计了周期性分布的Al纳米颗粒陷光结构,当颗粒半径R为50 nm,周期P为250 nm时,与参考电池相比,陷光结构太阳电池对AM1.5光谱光吸收提高百分比Eabs为9.78%,其中短波部分光吸收提高明显;当颗粒R=100 nm,P=500nm,总的光吸收提高百分比Eabs为12.76%,其中中长波段光吸收显著改善。利用不同尺寸的Al纳米颗粒,为微晶硅薄膜太阳电池设计出了一种双周期陷光结构,其光吸收提高百分比Eabs高达25.7%,达到了微晶硅薄膜太阳电池宽光谱陷光的要求。最后,结合不同波段的光吸收率和电磁场分布分析了电池的陷光机理。
[Abstract]:Large-scale application of solar cells should have two conditions: one is low cost, the other is high efficiency. Microcrystalline silicon thin film solar cells not only have the characteristics of abundant raw materials, mature low temperature film forming technology and relatively simple technology, but also can realize large area production on cheap substrates, which makes microcrystalline silicon thin film solar cells have low cost advantage. However, the thin optical absorption layer reduces the optical absorption, which leads to the low photoelectric conversion efficiency of microcrystalline silicon thin film solar cells. In the field of photovoltaic (PV), increasing the optical absorption efficiency of thin film solar cells by using the surface of metal nanoparticles isobaric trapping technology has attracted much attention. In this dissertation, the light management technology of solar cells is reviewed, and the application of surface isophosphors of metal nanoparticles in solar cells is introduced. The light scattering characteristics of metal nanoparticles and core-shell nanostructures were studied by COMSOL numerical simulation software based on finite element method. Finally, a wide-spectrum trapping structure was designed for microcrystalline silicon thin film solar cells. The main conclusions obtained are as follows: the light scattering properties of metal nanoparticles are studied as follows: the light scattering properties of spherical nanoparticles of different sizes are simulated and calculated. The results show that Ag and Al nanoparticles have the characteristics of high scattering and low absorption compared with Au-Cu. As the scattering center, the radius of spherical nanoparticles is about 100 nm. Compared with spherical nanoparticles, the coupling efficiency of hemispherical and cylindrical nanoparticles is higher than that of spherical nanoparticles. But the scattering cross section is low. 2. The light scattering characteristics of core-shell nanostructures; the thin oxide layer of 2 nm in Al _ (12) Al _ 2O _ 3 core-shell structure has little effect on the light scattering properties of metal core-shell nanoparticles. Under the same size, the light scattering performance of Alfilar Ag core-shell structure is better than that of Al. The properties of Si O2@Ag core-shell structure are greatly influenced by shell thickness and shell material. 3. The wide spectrum trapping structure of microcrystalline silicon thin film solar cell is designed. The periodically distributed Al nanoparticles trapping structure was designed on the front surface of microcrystalline silicon thin film solar cells. When the particle radius R is 50 nm and the period P is 250 nm, compared with the reference cells, the AM1.5 spectral absorption of the solar cells with trapping structure is increased by 9.78%, and the absorption of the shortwave part of the solar cells is increased obviously. The total optical absorption increase Eabs is 12.76, in which the medium and long band optical absorption is significantly improved. A dual-period trapping structure was designed for microcrystalline silicon thin film solar cells with different sizes of Al nanoparticles. The increase in optical absorption percentage (Eabs) was as high as 25.7%, which met the requirement of wide spectral trapping of microcrystalline silicon thin film solar cells. Finally, the light trapping mechanism of the battery is analyzed by combining the optical absorptivity and electromagnetic field distribution of different bands.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2;O613.72

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