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Migration of ions can lead to photoinduced phase separation, degradation, and current-voltage hysteresis in perovskite solar cells (PSCs), and has become a serious drawback for the organic-inorganic hybrid perovskite materials (OIPs). Here, the inhibition of ion migration is realized by the supramolecular cation-π interaction between aromatic rubrene and organic cations in OIPs. The energy of the cation-π interaction between rubrene and perovskite is found to be as strong as 1.5 eV, which is enough to immobilize the organic cations in OIPs; this will thus will lead to the obvious reduction of defects in perovskite films and outstanding stability in devices. By employing the cation-immobilized OIPs to fabricate perovskite solar cells (PSCs), a champion efficiency of 20.86% and certified efficiency of 20.80% with negligible hysteresis are acquired. In addition, the long-term stability of cation-immobilized PSCs is improved definitely (98% of the initial efficiency after 720 h operation), which is assigned to the inhibition of ionic diffusions in cation-immobilized OIPs. This cation-π interaction between cations and the supramolecular π system enhances the stability and the performance of PSCs efficiently and would be a potential universal approach to get the more stable perovskite devices.

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The carrier lifetime and the doping property of the lead halide perovskites are essential factors determining their application in solar cells. Hence, these two factors of the perovskite (CH 3 NH 3 PbI 3 ) film were managed by postannealing, and the underlying mechanisms governing their effects on the photovoltaic performance of the solar cells were investigated. The short carrier lifetime from electron-hole bimolecular recombination, corresponding to the fast decay of photoluminescence, is achieved in perovskite films annealed at high temperatures. The doping property of the perovskite varies from p-type, intrinsic to n-type with increasing annealing temperature. The short carrier lifetime and the intrinsic feature of the perovskite benefit for high open circuit voltage of the corresponding solar cells, whereas the n-type doped perovskite leads to the high photocurrent and efficiency. Through the management of the carrier lifetime and the doping property, highly efficient perovskite solar cells with conversion efficiency over 17% were prepared. These results provide new insights into the underlying relations between the perovskite properties and the device performance.