Application of an amphipathic molecule at the NiOx/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 NiOxsurface.The hydrophilic chain of Triton as a Lewis base additive can coordinate with the Ni3+on the NiOxsurface 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 NiOxsurface to prevent moisture from penetrating into the NiOx/perovskite interface.Consequently,the NiOx/Triton-based devices(MAPbI3as 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 N2at 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)3perovskite 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.