For the industrial screen-printed solar cell of Table 5.3, where the series resistance image was shown in Fig. 5.27, we first compare the calculated and measured global IV curves.
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Figure 5.31A shows the measured global IVcurve (green circles) and the calculated curve using the two-diode model (solid line). For this calculation, the parameters as given in Table 5.3 are used. The parameters J01, J02, and Rsh were determined with a least-square regression of the two-diode model to the measured data of the Jsc-Voc characteristics, the series resistance Rser, FF followed from the light-IV and Jsc – Voc characteristics and Jsc directly from the measured light-IV characteristics. This comparison of the simulated to the measured light-IVcharacteristic demonstrates that the global two-diode model does not describe well this solar cell.
Figure 5.31 Measured global IV data (green circles) of the industrial screen-printed solar cell of Table 5.3 and Figure 5.27 compared to calculation with the global two-diode model (A) and to the LIA approach (B).
Figure 5.31B shows the measured global IVcurve (green circles) and the calculated curve obtained from the LIA approach using a measured series resistance image. Both curves are in good agreement. For this solar cell, the LIA approach results in a more realistic IV characteristic than the two-diode model, shown in Fig. 5.31A. As a result of the LIA approach, an efficiency of 16.18% is obtained, which is in good agreement to the measured value of 16.04%.
7.1.1.2 Virtual data manipulation
We now virtually manipulate the series resistance image to the best local value of 0.7 O cm, as shown in Fig. 5.32. This new series resistance image is fed into the LIA approach again. The resulting new global energy conversion efficiency predicts a total power improvement by this manipulation of 0.27 mW/cm2.
