Industrial Demonstration of 18.5% Maximum Efficiency Inline-Diffused Additive-Free Acid-Textured DWS Multicrystalline Silicon Solar Cells.

Introduction of diamond-wire-sawing (DWS) technique has resulted in significant cost reduction for silicon (Si) wafering process. Unlike slurry-wire-sawn (SWS) wafers, DWS wafer has fewer, non-uniform and thinner saw damage surface. Acid texturing on such surfaces yield highly reflecting and non-uniform texture formation. An additive-free, low cost, non-metallic, energy efficient acid based texturing scheme, named as NCPRE acid texturing, is demonstrated here for DWS multicrystalline Si wafers. The NCPRE acid texturing process employs specific Hydrofluoric-Nitric acid solution to obtain uniform porous silicon (Por-Si) layer. A total of 672 and 1204 cells were fabricated employing the NCPRE acid texturing and additive based acid texturing processes respectively using inline industrial diffusion tools. An impressive batch efficiency of 18.25% is obtained for the NCPRE textured cells against 18.31% cost intensive additive based textured cells. Reasonably close values of cell efficiency establish NCPRE acid texturing a potential candidate for efficient and lowcost DWS mc-Si wafer texturing process. [ABSTRACT FROM AUTHOR]