Silicon Ingot Quality and Resulting Solar Cell Performance

This paper demonstrates that the electronic properties of a multicrystalline solar ingot can be used to predict the performance of solar cells manufactured from it. The lifetime and trap density are measured on as-cut bricks and are used to define a single metrological parameter termed “Q-Factor”. The Q-Factor scales with the performance of over a dozen ingots cast from experimental Solar-Grade Silicon. It has the unit of a lifetime and relates to the minority carrier lifetime at cell level. It is argued that the measurement of electronic properties of Silicon at brick level is a sensitive probe for contaminations and can be considered as complementary to a chemical analysis. It can predict the performance potential of the brick with the added advantage of being sensitive to the crystallization quality.