Figure 4

Numerical results for (a) the short circuit current density J _sc, (b) the fill factor FF, (c) the open circuit voltage V _oc, and (d) the overall power conversion efficiency PCE of the considered OSC as functions of varying pillar height. While the effect on Voc is limited, J _sc decreases noticeably for higher pillars. This decrease is addressed to the fact that in our simulations the active layer thickness (and not volume) is kept constant, which reduces the active layer volume of the absorbing material with increasing pillar height. However, the PCE reduction is not consistent with the lower absorption, which can be understood by considering the improved collection efficiency and thus, FF enhancement as a function of pillar height.