Low-cost texturization of large-area crystalline silicon solar cells using hydrazine mono-hydrate for industrial use

Abstract

Reduction in optical losses in mono-crystalline silicon solar cells by surface texturing is one of the important issues of modern silicon photovoltaics. In order to achieve good uniformity in pyramidal structures on the silicon surface, a mixture of sodium hydroxide (NaOH) or potassium hydroxide (KOH) and isopropyl alcohol (IPA) is generally used during texturization of mono-crystalline silicon solar cell. However, due to the high cost of IPA, there is always a search for alternate chemical which plays the same role as IPA during texturization for industrial solar cell production. For a better texturization, the interfacial energy between silicon and ionized electrolyte of chemical solution should be reduced to achieve sufficient wettability of the silicon surface, which will enhance the pyramid nucleation. In this work, we have investigated the role of hydrazine mono-hydrate as a surface-active additive, which supplies OH- ions after its dissociation. Our process cuts down the IPA consumption during texturing without any loss in uniformity of textured pyramids. We are the first to report the novel idea to add hydrazine mono-hydrate in NaOH solution for texturing monocrystalline silicon surface to fabricate solar cells with more than 85% yield in the efficiency range of 14.5-15.3%. (c) 2005 Elsevier Ltd. All rights reserved.