Lines 21 to 27 plot the external collection efficiency of the three cells. The resultis shown in Figure 16-11.The external collection efficiency is defined as the total photocurrent densityat that wavelength divided by the number of photons incident on the surface of thecell times the electronic charge q(=1.6e-19 C).This is different from QNTM.EFF, the quantum efficiency which is the electronhole-pair generation rate per photon inside the device and may be defined by theuser. The default value used in this example is 1.0.In this figure, the cell with 0.09 mm ITO exhibits a spike near 0.28 mm reflectingthe peak of the transmittance in the Figure 16-9. Both the short-circuit current andthe external collection efficiency of the cell with 0.03 mm ITO have much lowervalues over the wavelength range than the other cells. This is due to the poortransmittance beyond l=0.4 mm. The 0.06 mm ITO cell shows the greatest efficiencyover the 0.4 to 0.7 mm range where most of the solar energy is concentrated