Accurate series resistance measurement of solar cells

The series resistance ( R s ) of a solar cell is commonly represented as a constant resistance value. However, because of the distributed nature of series resistance, the effective lumped R s vary with current density and illumination intensity. Treating R s as a constant is usually insufficient for an accurate analysis of its J–V curve. This work first presents a review of the distributed nature of series resistance and commonly applied methods to measure R s . Particular attention is given to the multi‐light method (MLM) and it is discussed in detail, where R s in both the light and dark can be measured as a function of current by extracting R s from a set of current–voltage ( J–V ) curves attained at different illumination intensities. The principle behind this method is discussed, and the results are then compared with those of other known methods of R s measurement. The accurate measurement of R s ( J ) attained with the MLM permits the extraction of an R s ‐corrected J–V curve, which is theoretically more accurate than that attained by alternative methods because of negligible error from injection dependence and spectral mismatch. With the solar cell equation modified to include R s ( J ), we attain a much better fit to experimental data, finding a significant reduction in error compared with using a constant R s .