Investigating the charge transport kinetics in poly-crystalline silicon solar cells for low-concentration illumination by impedance spectroscopy

Commercially available polycrystalline silicon solar cells have been studied under varying illumination conditions to evaluate their application in low-concentration photovoltaic systems. The present work explores a detailed analytical framework for determining a broad range of performance indicating parameters for polycrystalline silicon solar cells by using the impedance spectroscopy (IS) technique. The IS measurements show that the diffusion capacitance varies from 1×10−7 to 5×10−7 F/cm2 and diffusion resistance from 0.5 to 770 Ω-cm2 with the applied bias. The IS measurements also indicated that the effective lifetime of charge carriers decreases with increasing illumination. This study confirms that commercially available polycrystalline silicon solar cells can work satisfactorily under low concentration (<3.5 suns).