Cesium iodide

Patterned glass-based ITO was purchased from Shenzhen Huayu Union Technology Co., Ltd. Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT: PSS) was purchased from Heraeus Precious Metals GmbH. Tin iodide (SnI₂), Cesium iodide (CsI), bathocuproine (BCP), tin powder (Sn), N, N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), toluene, tin (II) fluoride (SnF₂), guanidine thiocyanate (GuaSCN), and ethylenediamine (EDA) were purchased from Sigma-Aldrich. Methylammonium iodide (MAI) and formamidinium iodide (FAI) were purchased from Greatcell Solar Materials. Lead iodide (PbI₂) and [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz) were purchased from Tokyo Chemical Industry Co. Ltd (TCI). C₆₀ was purchased from Puyang Yongxin Fullerene Technology Co., Ltd. Quartz-based ITO was purchased from Luoyang Guluo Glass Co. Ltd. All materials and solvents were used as received without any further purification.

NaH (60% dispersion
in mineral
oil), 1-bromoHexane (%98), N-bromosuccinimide (NBS) ReagentPlus (99%),
carbazole (≥95%), n-buthyllithium solution
(2.5 M in Hexane), potassium carbonate, sodium hydroxide, trimethyl
borate (≥98%), and phosphorous(V) oxychloride (99.999%) were
purchased from MERC. Hexane, suitable for high-performance liquid
chromatography (HPLC), ≥97.0%, dichloromethane, suitable for
HPLC ≥99.8%; N,N-dimethylformamide,
anhydrous, 99.8%; chloroform, suitable for HPLC, ≥99.8%; and
tetrahydrofuran, ≥99.0% were purchased from MERCK. Spiro-OMeTAD
was purchased from Borun. Bis(trifluoromethane)sulfonimide lithium
salt (Li-TFSI, 99.0%) was purchased from Acros. Lead(II) bromide (PbBr₂, 99.999%), methylammonium bromide (MABr, >99.5%), and
formamidinium
iodide (FAI, >99.5%) were bought from Lumtec. Lead iodide (PbI₂, 99.99%) was bought from TCI. Titanium isopropoxide (Ti[OCH(CH3)₂]₄, 97%), hydrochloric acid (HCl, 37%), 2-propanol
(For HPLC, 99.9%), chlorobenzene (anhydrous 99.8%), acetonitrile (99.8%),
4-tertbutylpyridine (99.0%), and cesium iodide (CsI, 99.999%) were
purchased from Sigma-Aldrich. Fluorine-doped tin oxide (FTO) glass
slides (2.5 × 2.5 cm², FTO OPV-FTO22-15, sheet resistance
of 14 Ω sq^–1) were bought from OPVTech.

Lead iodide (PbI₂) is purchased from Alfa Aesar. Formamidinium iodide (FAI) and titanium dioxide paste (TiO₂-30 NRD) are purchased from Greatcell. 2,2′,7,7′-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (Spiro-OMeTAD) is purchased from Xi’an Polymer Light Technology Corp. Methylammonium lead tribromide (MAPbBr₃) was purchased from Share Chem. Ultra-dry dimethylformamide (DMF), dimethyl sulfoxide (DMSO), ethanol (EtOH), and chlorobenzene (CB) are purchased from Acros. Cesium iodide (CsI), 4-tert-butyl pyridine (TBP), lithium bistrifluorosulfonylimide (LiTFSI), acetonitrile (ACN), tetrahydrofuran (THF), acetylacetone, titanium diisopropoxide bis(acetylacetonate) 75 wt% in isopropanol, and methylammonium chloride (MACl) are purchased from Sigma-Aldrich. Fluorine-doped tin oxide (FTO) (10 Ω/sq) conductive glass is purchased from Nippon Sheet Glass (NSG). (Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine) (PTAA: 115 kDa) is purchased from Solaris Chem Inc. All the chemicals are used as received without further purification.

The PEDOT:PSS was purchased from Heraeus Deutschland GmbH and Co. KG, Hanau, Germany, Lead(II) bromide (PbBr₂) and lead(II) iodide (PbI₂) were acquired from TCI; formamidinium iodide (FAI) and methylammonium bromide (MABr) and were purchased from Dyenamo (99.99%). Cesium iodide (CsI) and all the anhydrous solvents, i.e., dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), and chlorobenzene (CB), were purchased from Sigma Aldrich (St. Louis, MO, USA) and used without further purification. The patterned indium tin oxide (ITO, 15 Ω/square) glass substrates were provided by Xin Yan Technology Ltd., Hong Kong.