The formation of undersaturated lead or iodide ions and I 2 on the perovskite surface can decrease the performance and stability of perovskite solar cells (PSCs). Additionally, the leakage of noxious lead limits the application of PSCs. Here, we develop a strategy for molecular modulation of a perovskite surface using thiol copper(II) porphyrin (CuP) to post-treat the perovskite film. The Raman spectra reveal that the CuP molecules anchor on the perovskite surface by a coordination interaction between the thiol-terminal of CuP and Pb ion in perovskite. DFT calculations demonstrate that the porphyrin core in CuP has a strong fixing effect on I − and I 2 by the induction force and electrostatic attraction. Such a fixation was demonstrated by the shift of the UV absorption peak of I 2 in solution with the addition of CuP and the decreased defects density in the CuP-treated perovskite film. Finally, the modified PSCs exhibit an improved cell performance with the best efficiency up to 21.76% (certified 20.97%). The modified PSCs acquired significantly improved stability. In addition, there is almost no lead leakage from the treated film immersed in water. This work provides a surface modulation strategy by thiol CuP treatment to fabricate efficient, stable, and environmental-friendly PSCs.

Inhibiting the ions migration and even irreversible reactions have been regarded as one of the most important factors for fabricating efficient and stable perovskite solar cells (PSCs). Here, we employed the diamine cobalt(II) porphyrin [Co(II)P] to treat a perovskite film to construct in situ Co(II)P-based coordination polymer on the perovskite film. The crystal structure of the polymer indicated a central cobalt (Co) ion in one Co(II)P coordinated with two amine units from a different neighboring Co(II)P to form an overall three-dimensional (3D) structure. Such a 3D network covered on the perovskite surface could prevent the migration of ions from the perovskite. Furthermore, the limited amount of diatomic iodine (I 2 ) released in the perovskite due to iodide oxidation defects could be reduced to Iby the Co(II) ion in the polymer, and thus, achieve regeneration. Finally, the Co(II/III) ion pair formed in the polymer facilitated the charge transfer and boosted to the best efficiency up to 21.3%. Remarkably improved cell stability under moisture, heating, or light was also achieved.The control PSCs with Zn-based 3D polymer and Co-based 1D polymer exhibited the poor cell efficiencies and stabilities than those of the 3D Co porphyrin-based PSC to verify the effect of 3D Co porphyrin-based polymer in stabilizing the perovskite film. This work provides a new encapsulation and regeneration strategy via in situ construction of a Co(II) porphyrin-based coordination polymer on perovskite film for efficient and stable PSCs.

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Two solvent-induced luminescent MOFs have been synthesized and MOF1 can be employed as a dual-functional fluorescence sensor for nitroaromatics and antibiotics.