Multifunctional Anti-Corrosive Interface Modification for Inverted Perovskite Solar Cells

摘要

The interface stability and non-radiative recombination loss of the cathodeinterface greatly limit the stability and performance of inverted perovskitesolar cells (PSCs). Here, an efficient multifunctional anti-corrosive interfacemodification strategy based on 2,2′-(1,3-phenylene)-bis[5-(4-tertbutylphenyl)-1,3,4-oxadiazole] (OXD-7) is proposed to overcome the cathodeinterface issues. OXD-7 molecules chemically coordinate to the Ag electrodeand form a chemically stable complex film of OXD7-Ag, which suppresseshalide ion migration and thus enhances the corrosion resistance of theelectrode as well. In addition, the trap density of perovskite film, PCBM/Aginterfaces contact, the built-in potential, moisture resistance, as well as theunfavorable interface exciton dissociation elimination of the devices, are alsoimproved with the OXD-7 arrangement upon PCBM film, which correspondinglyenhances the device performance and stability. Bidirectional halide ionmigration and the ITO corrosion are observed, which is also suppressedby the OXD-7 modification. The high power conversion efficiency (PCE) of21.84% and the high fill factor (≈84.63%) is obtained via this strategy, whichis one of the highest PCEs and FFs based on solution-process MAPbI_3/PCBMheterojunctions. The PCE can maintain ≈80% of its initial value after 1080 hat 85 ℃ with OXD-7 modification.