Improvement of Screen-Printed Textured Monocrystalline Silicon Solar Cell Performance by Metal-Assisted Chemical Etching

Abstract

In this work, we investigate the potential use of stain etched porous silicon as one possible way to increase the silicon solar cell efficiency at low cost. A very simple method for the formation of porous silicon antireflection coatings on random pyramid textured screen-printed monocrystalline silicon solar cells is described. The process is based on electroless metal-assisted chemical etching by immersion of the fully processed cell in HF-H2O2-Ethanol without masking the contacts. Characterization of the porous silicon layer using SEM, EDX and UV-VIS-NIR spectrophotometry revealed that silver nanoparticles that are dissolved from the unmasked front grid contact by the HF acid greatly enhance the dissolution rate and therefore serve as catalysts for the porous silicon etching. The solar cell weighted reflectance was reduced from 45.08% to 22.01% after texturization and dropped further to 11.34% after porous silicon formation under optimized conditions. The porous silicon antireflection layer led to a relative improvement of 24.64% in the short-circuit current density without fill factor deterioration. The open-circuit voltage increased by ∼7mV and the cell efficiency was raised by 2.3% absolute. The simplicity of the process makes it attractive for the cost-effective production of silicon solar cells.