硅酸钠在太阳能电池单晶硅表面织构化的作用

EFFECT OF SODIUM SILICATE ON TEXTURE OF SINGLE CRYSTALLINE SILICON WAFER FOR SOLAR CELL

在单晶硅太阳电池的制备过程中,通常利用晶体硅[100]和[111]不同晶向在碱溶液中各向异性腐蚀特性,在表面形成类似于“金字塔”的绒面结构,使得入射光在硅片表面多次反射,提高入射光吸收效率,可提高单晶硅太阳电池的转换效率。实验探索了一种廉价的硅织构化腐蚀技术,即单独采用Na_2Si O_3代替传统的氢氧化钠和异丙醇溶液,以减少价格较高的异丙醇的用量,降低成本。不采用异丙醇或其他机械消泡的条件下,用质量分数为5%的Na_2Si O_3溶液在80℃腐蚀120min,单晶硅片表面可获得最佳反射率为12.56%的减反射绒面。虽然与传统的氢氧化钠和异丙醇溶液效果相比,单独使用Na_2SiO_3溶液腐蚀单晶硅片表面的反射率和均匀性略差,但在传统的氢氧化钠和异丙醇体系中加入质量分数为0.1%的Na_2Si O_3也会促进腐蚀反应的进行,获得更加均匀的减反射绒面。

In the production process of single crystal silicon solar cells, a pyramid type suede structure on the single crystal silicon wafer is formed by anisotropic corrosion of the [100] and [111] dirctions of single crystal silicon in the alkaline solution. This structure can enhance the efficiency of the solar cell because its multi-reflection results in the increase of the absorptivity of incidence light. A cheaper solution of Na2SiO3 is used instead of the conventional solution of NaOH ＋IPA （isopropyl alcohol） in the c-Si wafer etching process. A wafer with a suede structure and a mean reflectivity of about 12.56% was obtained after corrosion with 5% （in mass）Na2SiO3 solution at 80 ℃ for 120 min without mechanical de-bubbling. The reflectivity and uniformity on the surface of wafers corroded by using Na2SiO3 solution only are not as good as those corroded by using the NaOH ＋IPA solution. Furthermore, the addition of a small quantity of Na2 SiO3 into a conventional sodium solution of NaOH ＋ IPA can greatly promote the etching reaction in the process and obtain a more homogeneous anti-reflection texture.