Low temperature‐coefficient for solar cells processed from solar‐grade silicon purified by metallurgical route

This study is dedicated to the temperature (T)-variation of the photovoltaic performances of solar cells made from solar-grade silicon directly purified by metallurgical route (SoGM-Si). Experimental results were systematically compared with those for standard electronic-grade silicon (EG-Si) solar cells. We showed that the conversion efficiency (η) of SoGM-Si cells decreases much less when T increases than the η of EG-Si cells. This major difference is due to a strong increase with T of the short-circuit current density (Jsc) of the SoGM-Si solar cells. We showed that this a priori unexpected result could be described and explained by numerical simulations, by taking into account the main particularities of SoGM-Si: dopant compensation, moderate minority carrier diffusion length and larger amount of boron–oxygen complexes. These results are significant since T of a solar module under illumination being generally higher than 25°C, modules made from low-cost SoGM-Si cells should have performances closer to those of standard EG-Si solar panels. Copyright © 2011 John Wiley & Sons, Ltd.