Precise Analysis of Surface Recombination Velocity in Crystalline Silicon Solar Cells Using Electroluminescence

Abstract

To increase the conversion efficiency of crystalline silicon (c-Si) solar cells, reduction of surface recombination is essentially important, and precise evaluation of surface recombination velocity becomes crucial to the development of high-efficiency cells. We propose a new evaluation technique for surface recombination velocity in crystalline Si cells using electroluminescence (EL). The intensity of EL was found to be proportional to the total number of minority carriers in the base layers of solar cells. The number of minority carriers was affected sensitively by the surface recombination; thus, we can achieve the quantitative information of the surface recombination velocity by measuring EL intensity under typical forward injection current. By comparing with the results obtained by the conventional spectral response method, the validity of the proposed precise evaluation method has been proved in cases of practical passivation processes on the rear surfaces of base layers.