Shunt resistance and saturation current determination in CdTe and CIGS solar cells. Part 1: a new theoretical procedure and comparison with other methodologies

A new proposal for the extraction of the shunt resistance (R-sh) and saturation current (I-sat) of a current-voltage (I-V) measurement of a solar cell, within the one-diode model, is given. First, the Cheung method is extended to obtain the series resistance (R-s), the ideality factor (n) and an upper limit for I-sat. In this article which is Part 1 of two parts, two procedures are proposed to obtain fitting values for R-sh and I-sat within some voltage range. These two procedures are used in two simulated I-V curves (one in darkness and the other one under illumination) to recover the known solar cell parameters R-sh, R-s, n, I-sat and the light current I-lig and test its accuracy. The method is compared with two different common parameter extraction methods. These three procedures are used and compared in Part 2 in the I-V curves of CdS-CdTe and CIGS-CdS solar cells.