异质结太阳电池衬底陷光优化及其应用

发布时间：2018-06-16 10:24

本文选题：四甲基氢氧化铵 + 制绒　；参考：《河北工业大学》2015年硕士论文

【摘要】：硅异质结(SHJ)太阳电池以其低温制备、低成本、高转换效率和高稳定性,成为近年来太阳电池研究的热点。硅片表面制绒可增强光吸收,减少太阳光的反射,提高太阳电池效率。目前较为常见的制绒方法大多采用无机碱NaOH/KOH制绒、硅酸钠制绒,碳酸钠/碳酸氢钠制绒等,这些制绒方法的优点是工艺成熟,价格低廉。缺点是易引入Na、K金属离子污染。而四甲基氢氧化铵(TMAH)是一种有机碱,无害,高各向异性选择比,无金属离子污染的试剂。本文利用有机碱-四甲基氢氧化铵(TMAH)制绒,优化了硅片的光学特性、电学性能和硅片表面形貌,找出了适合异质结太阳电池的硅片衬底工艺参数。主要的研究如下:(1)用酸或碱刻蚀切割片,去除硅片表面损伤层后,用同样条件制绒,研究初始硅片形貌对硅片绒面和后续钝化的硅片的少子寿命的影响。利用高浓度碱液去除硅片表面损伤层,获得平整、缺陷少的平面。制绒后的金字塔布满表面,均匀独立,有利于反射的降低和硅片的钝化。利用混酸去除硅片表面损伤层,获得凹凸的沟壑表面,制绒后的金字塔未布满表面,有较多缺陷,不利于反射率的降低和后续钝化效果。(2)采用TMAH对硅单晶进行高效制绒。分别控制TMAH浓度、溶液温度、腐蚀时间和异丙醇(IPA)浓度进行硅片制绒,研究这些参数对绒面效果和衬底陷光特性的影响,从而得到优化的TMAH制绒的条件,并将优化后的衬底应用到硅异质结(SHJ)太阳电池上,改善电池性能,使电池效率由14.4%提高到17.8%。(3)在优化的绒面金字塔条件下,采用金属辅助化学刻蚀(MACE)的方法在金字塔上制备出了纳米线结构,得到双层(金字塔/纳米线)陷光结构,进一步增强衬底的陷光特性,使得硅片衬底的反射率降到5%以下,同时分析了不同刻蚀时间双层陷光结构的特性,并将其应用到硅异质结太阳电池中。
[Abstract]:Silicon heterojunction SHJ solar cells have become a hot research area in recent years due to their low temperature fabrication, low cost, high conversion efficiency and high stability. The surface velvet of silicon wafer can enhance the absorption of light, reduce the reflection of sunlight and improve the efficiency of solar cells. At present, the most common methods are inorganic base NaOH / Koh, sodium silicate, sodium carbonate / sodium bicarbonate, etc. The advantages of these methods are that the process is mature and the price is low. The drawback is that it is easy to introduce NaOK metal ion pollution. Tetramethylammonium hydroxide (TMAH) is a kind of organic alkali, harmless, high anisotropic selective ratio and free of metal ion contamination. By using organic alkali-tetramethyl ammonium hydroxide (TMAH), the optical properties, electrical properties and surface morphology of silicon wafers were optimized, and the technological parameters of wafer substrates suitable for heterojunction solar cells were found out. The main results are as follows: (1) the effect of initial wafer morphology on the minority carrier lifetime of silicon wafer and passivated silicon wafer was studied by etching the cut slice with acid or alkali, removing the damage layer on the surface of silicon wafer, and making velvet under the same conditions. The surface damage layer of silicon wafer was removed by high concentration alkali solution, and a flat plane with less defects was obtained. The pile-made pyramid is covered with a uniform and independent surface, which is conducive to the reduction of reflection and passivation of the silicon wafer. The surface damage layer of silicon wafer was removed by mixed acid, and the concave and convex groove surface was obtained. The pyramids after making pile were not covered with the surface, and there were many defects, which was not conducive to the reduction of reflectance and the passivation effect. 2) TMAH was used to make high efficiency velvet of silicon single crystal. TMAH concentration, solution temperature, corrosion time and IPA-isopropanol concentration were respectively controlled to prepare the velvet on silicon wafer. The effects of these parameters on the surface effect and substrate trapping characteristics were studied, and the optimized conditions of TMAH velvet making were obtained. The optimized substrate was applied to the silicon heterojunction SHJ solar cells to improve the performance of the cells, and the efficiency of the cells was increased from 14.4% to 17.88%. The nanowire structure was prepared on the pyramid by metal assisted chemical etching (MACEE) method, and the double layer (pyramid / nanowire) trapping structure was obtained, which further enhanced the trapping characteristics of the substrate and reduced the reflectivity of the silicon substrate to less than 5%. At the same time, the characteristics of double-layer trapping structure with different etching time are analyzed and applied to silicon heterojunction solar cells.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM914.4

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