Department of Optical Science and Engineering, and Shanghai Ultra-Precision Optical Manufacturing Engineering Center, Fudan University, Shanghai 200433, People's Republic of China.
Nanotechnology. 2016 Oct 21;27(42):425207. doi: 10.1088/0957-4484/27/42/425207. Epub 2016 Sep 19.
A p-n junction was made on p-type Si〈100〉 wafer (15 × 15 × 0.2 mm(3) in size) via phosphorous diffusion at 900 °C. Porous Si (PSi) with ultralow reflectivity (<0.3% in the ultraviolet and visible regimes) was achieved by etching a Ag-coated n(+) Si emitter in a solution of HF, H2O2 and H2O. The PSi was found to mainly consist of Si nanocrystallites with bandgap widths larger than that of bulk Si. Compared to other micro- or nanostructured Si-based crystalline-Si solar cells found in the literature, this PSi one possessed the feature of a graded band gap, which helped to suppress the surface recombination. In addition, the preparation method was readily applicable on large-scale-sized Si wafers. Also, the PSi acted as a down-shifter that absorbed the ultraviolet/violet light to which the Si solar cell responded poorly, and emitted a red one to which the cell responded well. Front and rear surface passivations were conducted by using SiO2 and Al2O3, respectively, to suppress the surface recombination and to facilitate the charge transfer. Indium-tin-oxide was used as the front electrode that was in good contact with the PSi, and Al was used as the rear one. For such a PSi-emitter crystalline-Si solar cell, enhancements of the photovoltaic responses from the ultraviolet to near-infrared regimes were observed; the open-circuit voltage was 606.8 mV, the short-circuit current density was 40.13 mA cm(-2), the fill factor was 0.779 and the conversion efficiency was 18.97%.
在 900°C 下通过磷扩散在 p 型 Si〈100〉晶片（尺寸为 15×15×0.2 毫米（3））上制作了 p-n 结。通过在 HF、H2O2 和 H2O 的溶液中蚀刻涂覆有 Ag 的 n(+)Si 发射器，获得了具有超低反射率（在紫外和可见区域<0.3%）的多孔硅（PSi）。PSi 主要由带隙宽度大于体 Si 的 Si 纳米晶组成。与文献中发现的其他基于微结构或纳米结构的 Si 的结晶硅太阳能电池相比，这种 PSi 具有渐变带隙的特点，有助于抑制表面复合。此外，该制备方法易于应用于大规模 Si 晶片。此外，PSi 充当了一个下转换器，吸收了 Si 太阳能电池对其响应不佳的紫外/紫光，并发出了 Si 太阳能电池对其响应良好的红光。通过分别使用 SiO2 和 Al2O3 对前表面和后表面进行钝化，以抑制表面复合并促进电荷转移。氧化铟锡（ITO）用作与 PSi 良好接触的前电极，而铝用作后电极。对于这种 PSi 发射器结晶硅太阳能电池，观察到从紫外到近红外区域的光伏响应增强；开路电压为 606.8 mV，短路电流密度为 40.13 mA cm(-2)，填充因子为 0.779，转换效率为 18.97%。
