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 (SoG_M‐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 SoG_M‐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 (J_sc) of the SoG_M‐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 SoG_M‐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 SoG_M‐Si cells should have performances closer to those of standard EG‐Si solar panels. Copyright © 2011 John Wiley & Sons, Ltd.