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

A new analytical method for determining all diode parameters using dark I-V 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 R_s has been presented in this work, which uses only I, V values of four nearby points in high-voltage region of the dark forward 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 (R_s, R_sh, I₀₁, n₁ and I₀₂, n₂) matched excellently well with the experimental I-V characteristics of the cells obtained under dark conditions and under simulated AM1.5 G 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.