Nickel 2 chloride hexahydrate

Chitosan (deacetylation degree, 90%), nickel (II) chloride hexahydrate (NiCl₂·6H₂O; 99.9%), copper (II) chloride dihydrate (CuCl₂·2H₂O; 99.9%), ethylene glycol (EG; 99.8%), hydrazine monohydrate (N₂H₄·H₂O; 80%), SDS, and acetic acid (HAc; 98%) were purchased from Sinopharm Chemical Reagent Co., Ltd., Shanghai, China. Copper plate, platinum plate, and other chemicals were obtained from commercial sources in China. All chemicals were of analytical grade and were used as received without further purification.

Cesium iodide (CsI, 99.999%), lead iodide (PbI₂, 99.9%), lead bromide (PbBr₂, 99.9%), dimethyl sulfoxide (DMSO, 99.8%), isopropanol (IPA,  ≥ 99.5%), bis(trifluoromethane)sulfonimide lithium salt (Li-TFSI, 99.95%), 4-tert-Butylpyridine (tBP, 96%) and toluene (TL, anhydrous, 99.8%) were purchased from Sigma-Aldrich. Tin (IV) oxide (15% in H₂O colloidal dispersion) was purchased from Alfa-Aesar. Nickel(II) chloride hexahydrate (NiCl₂·6H₂O, AR, ≥ 98.0%), citric acid monohydrate (C₆H₈O₇·H₂O, AR, ≥ 99.5%), sodium sulfate (Na₂SO₄, AR, ≥ 99.0%), sodium carbonate (Na₂CO₃, AR, ≥ 99.8%), sodium nitrate (NaNO₃, AR, ≥ 99.0%), trisodium phosphate dodecahydrate (Na₃PO₄·12H₂O, AR, ≥ 98.0%), sodium metasilicate nonahydrate (Na₂SiO₃·9H₂O, AR, ≥ 98.0%) were purchased from Sinopharm Chemical Reagent Co., Ltd. Formamidinium iodide (FAI) was purchased from Great Cell. Methylammonium iodide (MAI), methylammonium chloride (MACl), poly(3-hexylthiophene-2,5-diyl) (P3HT) were obtained from Xi’an Polymer Light Technology Corp. 2,2’,7,7’-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9’-spirobifluorene] (spiro-OMeTAD), [6 (link), 6 (link)]-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM, 99.5%) and bathocuproine (BCP, 99%) were purchased from Nichem chemicals. Fluorine-doped tin oxide (FTO) substrates (8 Ω sq⁻¹) and indium-doped tin oxide (ITO) substrates (7 Ω sq⁻¹) were purchased from Nippon Sheet Glass.