Performance optimization by considering current matching in polymer tandem solar cells

Considering current matching of the subcells, the optimized active layer thicknesses are obtained for structures of ITO/PEDOT:PSS/P3HT:PCBM/ZnO/PED-OT:PSS/pBBTDPP2:PCBM/Al (normal) and ITO/PED-OT:PSS/pBBTDPP2:PCBM/ZnO/PEDOT:PSS/P3HT:P-CBM/Al (reverse) by detailed optical simulations, respectively. Because of the different layer sequences and material properties, it is observed that the normal structure shows its superiority in current matching when the active layers are relatively thick. However, the reverse structure shows better performance as the active layers are relatively thin. The results are very instructive since we can choose the thinner reverse structure to achieve matching short circuit current density (J
_SC
).