The I-V curves are shown in Figure 4c, and the results are summarised inTable2.The Ca and Cb devices show efficiencies of 0.50% and 0.52%, Voc values of 0. 501 V and 0.498 V, FF values of 50.18% and 59.68% and Jsc values of 2.0 mA/cm2 and 1.74 mA/cm2 for Ca
and Cb, respectively. The efficiency and FF values of Cb are higher than those of Ca, which shows that the Cb structure is more efficient compared to that of Ca in terms of gathering scattering energy. Note that the area of Ca is large than Cb, so the scattering light in Ca attenuated bigger than that in Cb. The properties of the device Cc are worse than Ca and Cb, probably because of decreased scattering.