Nanostructured multi-crystalline silicon solar cell with isotropic etching by HF/KMnO4.

Metal-assisted chemical etching (MACE) method is an efficient way to improve the power conversion efficiency of solar cell by developing nanostructures. Normally, hydrogen peroxide is widely used as an oxidizing agent, through which anisotropic etching of nanostructures could be achieved. Here, nanoscale textured multi-crystalline silicon (mc-Si) solar cell with an efficiency of 18.13% was fabricated by MACE method with potassium permanganate (KMnO4) as an oxidizing agent. The isotropic etching by KMnO4 showed the great uniformity of surface reflectance, corresponding to the isotropic oval pits. The solar cell presented an increase of 0.72mA · cm−2 in the short-circuit current density comparing with the mc-Si solar cell fabricated by the traditional process. Though the efficiency still needed optimizing, isotropic etching for mc-Si would lead a new tendency for MACE technique. [ABSTRACT FROM AUTHOR]