Effect of illumination intensity on cell parameters of a silicon solar cell

The effect of illumination intensity Pin on the cell parameters of a silicon solar cell has been investigated based on one diode model. The variation of slopes of the I–V curves of a cell at short circuit and open circuit conditions with intensity of illumination in small span of intensity has been applied to determine the cell parameters, viz. shunt resistance Rsh, series resistance Rs, diode ideality factor n and reverse saturation current I0 of the cell. The dependence of cell parameters on intensity has been investigated for a fairly wide illumination intensity range 15–180 mW/cm2 of AM1.5 solar radiations by dividing this intensity range into a desirable number of small intensity ranges for measurements of the slopes of the I–V curves at short circuit and open circuit conditions. Initially Rsh increases slightly with Pin and then becomes constant at higher Pin values. However, Rs, n and I0 all decrease continuously with Pin, but the rate of decrease of each of these becomes smaller at higher Pin values. Theoretical values of open circuit voltage Voc, curve factor CF and efficiency η calculated using the cell parameters determined by the present method match well with the corresponding experimental values.