Litfsi

The SnO₂ colloidal dispersion in H₂O (tin (IV) oxide, 15 wt%) was purchased from Alfa Aesar. The lead iodide (PbI₂) (> 99.99%), FAI (≥ 99.5%), MAI (≥ 99.5%), methylammonium chloride (MACl) (> 99.5%), spiro-OMeTAD (≥ 99.8%), LiTFSI (> 99%), TBP (> 96%) and PEAI (≥ 99.5%) were purchased from Xi’an Polymer Light Technology Corp. (China). The 1,4-DITFB (97%) was obtained from Macklin. The N,N-dimethylformamide (DMF, 99.9%) and dimethyl sulfoxide (DMSO, 99%) were obtained from J&K Scientific. The isopropanol (IPA, ≥ 99.7%) was purchased from Sinopharm Chemical Reagent Co., Ltd.

PbI₂ (99.999%, Sigma‐Aldrich), PbBr₂ (99%, Sigma‐Aldrich), CsI (99.9%, Sigma‐Aldrich), methylammonium bromide (MABr, 99%, Deysol), formamidinium iodide (FAI, 99%, Deysol), 2′,7,7′‐tetrakis‐(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (Spiro‐MeOTAD, 99.5%, Xi'an Polymer Light Technology Corp.), 4‐tert‐butylpyridine (tBP, 96%, Xi'an Polymer Light Technology Corp.), lithium bis(trifluoromethanesulfonyl)imide (Li‐TFSI, 99%, Xi'an Polymer Light Technology Corp.), SnO₂ colloid precursor (15% in H₂O, Alfa Aesar), chlorobenzene (CB, 99.8%, Sigma‐Aldrich), acetonitrile (99.9%, Sigma‐Aldrich), N,N‐dimethylformamide (DMF, 99.8%, Sigma‐Aldrich), dimethyl sulfoxide (DMSO, 99.8%, Sigma‐Aldrich), and fluorine‐doped tin oxide (FTO)‐coated glass substrates (Shanghai Materwin Corp.) were used as received.