A novel analytical method for determination of diode parameters from the dark forward I–V characteristics of a silicon solar cell

Abstract

A new analytical method for determining all diode parameters using dark characteristics of a silicon solar cell is presented. This method has an advantage because the low- and high-voltage regions of the dark forward I-V characteristics of silicon solar cells can be described accurately by single-diode model, and only for the middle voltage region that the double-diode model may need to be applied. In view of this, a new methodology for the determination of series resistance Rs has been presented in this work, which uses only I, V values of four nearby points in the forward dark I-V characteristics and does not require knowledge of any other diode parameters. Applying the single- and double-diode models, the methodologies for determination of reverse saturation currents and ideality factors (I0, n for single diode model) and (I01, n1 and I02, n2 for the double diode model) have been described. The present method of measurement of the diode parameters was applied to three silicon solar cells. Theoretical I-V curves generated using so determined values of diode parameters (Rs, Rsh, I01, n1 and I02, n2) matched excellently well with the experimental I-V characteristics of the cells obtained under dark conditions and under simulated AM1.5G solar radiation up to 50 mW cm-2 intensity. We found that for higher intensities of illumination, while all other parameters remain constant, the value of I01,which is a representative parameter of bulk recombination, is slightly decreased with the increase in intensity.