Effect of Cs-Incorporated NiOx on the Performance of Perovskite Solar Cells

The effect of Cs-incorporated NiO x on perovskite solar cells with an inverted structure was investigated, where NiO x and PCBM were used as selective contacts for holes and electrons, respectively. It was found that the generation of an Ni phase in an NiO x layer was significantly suppressed by employing cesium. Furthermore, Cs-incorporated NiO x enabled holes to be efficiently separated at the interface, showing the improved photoluminescent quenching and thus generating higher short-circuit current. The effect of Cs incorporation was also prominent in the inhibition of recombination. The recombination resistance of Cs-incorporated NiO x was noticeably increased by more than three-fold near the maximum power point, leading to a higher fill factor of 0.78 and consequently a higher power conversion efficiency of 17.2% for the device employing Cs-incorporated NiO x .