Degradation of solar cells made of upgraded metallurgical grade silicon

The aging effect of solar cells made of upgraded metallurgical grade silicon under continued exposure to ultraviolet light has been studied. It has been observed that in 3 years the cell degrades from 6.6% to 4.7% in efficiency mainly because of an increase in reflectivity and a decrease in the shunt resistance. Measurements of diode ideality factors and reverse saturation current densities revealed that the overall junction and the material quality suffered significantly large damages.