Department of Micro and Nanotechnology, Middle East Technical University, Ankara 06800, Turkey. Center for Solar Energy Research and Applications, Middle East Technical University, Ankara 06800, Turkey.
Nanotechnology. 2017 Oct 6;28(40):405205. doi: 10.1088/1361-6528/aa81b9.
Reducing silicon (Si) wafer thickness in the photovoltaic industry has always been demanded for lowering the overall cost. Further benefits such as short collection lengths and improved open circuit voltages can also be achieved by Si thickness reduction. However, the problem with thin films is poor light absorption. One way to decrease optical losses in photovoltaic devices is to minimize the front side reflection. This approach can be applied to front contacted ultra-thin crystalline Si solar cells to increase the light absorption. In this work, homojunction solar cells were fabricated using ultra-thin and flexible single crystal Si wafers. A metal assisted chemical etching method was used for the nanowire (NW) texturization of ultra-thin Si wafers to compensate weak light absorption. A relative improvement of 56% in the reflectivity was observed for ultra-thin Si wafers with the thickness of 20 ± 0.2 μm upon NW texturization. NW length and top contact optimization resulted in a relative enhancement of 23% ± 5% in photovoltaic conversion efficiency.
降低光伏产业中硅（Si）晶圆的厚度一直是降低整体成本的要求。通过减少 Si 厚度，还可以获得缩短收集长度和提高开路电压等进一步的好处。然而，薄膜的问题是光吸收不良。减少光伏器件光学损耗的一种方法是最小化前侧反射。这种方法可以应用于前接触式超轻薄结晶硅太阳能电池，以增加光吸收。在这项工作中，使用超轻薄和灵活的单晶 Si 晶圆制造了同质结太阳能电池。采用金属辅助化学刻蚀法对超薄 Si 晶圆进行纳米线（NW）织构化，以补偿弱光吸收。在厚度为 20 ± 0.2μm 的超薄 Si 晶圆上进行 NW 织构化后，反射率相对提高了 56%。通过优化 NW 长度和顶接触，光伏转换效率相对提高了 23% ± 5%。
