Towards 18% efficiency on below 100µm thick multicrystalline silicon wafers from the RST process

Abstract

The RST process is a ribbon process aimed at producing low cost and very thin multicrystalline silicon wafers, with a wafer cost perspective down to 10 €-cent/Wp, provided high conversion efficiency can be reached. A general approach has been identified for the achievement of 18% conversion efficiency on solar cells made out of the RST material. This approach firstly relies on the implementation of high efficiency solar cell processes adapted to the <100 μm RST wafers. The necessary improvement of the material quality is expected through (i) the reduction of the density of SiC inclusions at the cell surface for the achievement of high FF values, and (ii) the increase of the minority carrier lifetime by both the reduction of the metallic contamination and the control of the crystalline texture of the silicon ribbon.n.