Application of an amphipathic molecule at the NiO /perovskite interface for improving the efficiency and long-term stability of the inverted perovskite solar cells

The presence of defects and detrimental reactions at NiOx/perovskite interface extremely limit the efficiency performance and long-term stability of the perovskite solar cells (PSCs) based on NiOx. Herein, an amphipathic molecule Triton X100 (Triton) is modified on the NiOx surface. The hydrophilic chain of Triton as a Lewis base additive can coordinate with the Ni3+ on the NiOx surface which can passivate the interfacial defects and hinder the detrimental reactions at the NiOx/perovskite interface. Additionally, the hydrophobic chain of Triton protrudes from the NiOx surface to prevent moisture from penetrating into the NiOx/perovskite interface. Consequently, the NiOx/Triton-based devices (MAPbI3 as absorbing layer) show superior moisture and thermal stability, retaining 88.4% and 64.3% of the initial power conversion efficiency after storage in air (40%–50% relative humidity (RH)) at 25 ℃ for 1070 h and in N2 at 85 ℃ for 800 h, respectively. Moreover, the efficiency increases from 17.59% to 19.89% because of the passivation defect and enhanced hole-extraction capability. Besides, the NiOx/Triton-based PSCs with Cs0.05(MA0.15FA0.85)0.95Pb(I0.85Br0.15)3 perovskite as the light-absorbing layer also exhibits better moisture and thermal stability compared to the control devices, indicating the viability of our strategies. Of particular note, a champion PCE of 22.35% and 20.46% was achieved for small-area (0.1 cm2) and large-area (1.2 cm2) NiOx/Triton-based devices, respectively.