Greater than 16% Efficient Screen Printed Solar Cells on 115-170 μm Thick Cast Multicrystalline Silicon

Abstract

In this paper we report on the impact of mc-Si wafer thickness on efficiency. We have obtained 16.8%, 16.4%, 16.2% and 15.7% efficient screen printed 4 cm(2) solar cells on 280 μm, 170 μm, 140 μm and 115 μm thick cast mc-Si respectively. Analysis of these cells showed that the efficiency of the 115 μm thick cell is limited by a BSRV of 750 cm/s, FSRV of 120,000 cm/s and a BSR of 67%. A module manufacturing cost model for a 25 MW plant was used to demonstrate that 15.7% efficient cells on 115 μm thick wafers are more cost effective than 16.8% cells on 280 μm wafers. The module manufacturing cost reduced from $1.82/W to $1.63/W when the wafer thickness was reduced from 280 μm (efficiency 16.8%) to 115 μm (efficiency 15.7%). A roadmap is developed for 115 μm thick wafers to demonstrate how cell efficiency can be increased to greater than 18% resulting in a module cost of less than $1.40/W.