Phenethylammonium iodide peai

All the organic chemicals and solvents were purchased from Sigma-Aldrich and Alfa Aesar and used directly without further purification. Lead iodide (PbI₂), 1-octadecene (ODE), oleic acid (OA), cesium carbonate (Cs₂CO₃), n-hexane, n-octane and lithium bis(trifluoromethylsulfonyl)imide (Li-TFSI) were purchased from Alfa Aesar. Oleylamine (OLA), sodium acetate (NaOAc), chlorobenzene (CB), chloroform (CF), acetonitrile (AN), methyl acetate (MeOAc) and ethyl acetate (EtOAc) were purchased from Sigma-Aldrich. Phenethylammonium iodide (PEAI) was purchased from GreatcellSolar. TiO₂ precursor solution (SC-BT060) and 2 M TiCl₄ aqueous solution were purchased from Sharechem. 2,20,7,70-Tetrakis(N,N-di-p-methoxyphenylamine)-9,90-spirobifluorene (Spiro-OMeTAD) was purchased from Lumtec. 2-Amylpyridine was purchased from TCI.

Lead iodide (PbI₂), tin iodide (SnI₂), PVK, TPBi, LiF, chlorobenzene, isopropyl alcohol (IPA), and dimethyl sulfoxide (DMSO) were purchased from Sigma-Aldrich. Phenethylammonium iodide (PEAI) was purchased from Greatcell Solar. PC₆₁BM was purchased from 1-Materials. PEDOT:PSS was purchased from Clevios. All chemicals are used as received without further purification. The precursor solution of PEA₂PbI₄ was prepared by mixing PEAI (0.8 M) and PbI₂ (0.4 M) in DMSO (1 mL). The precursor solution of PEA₂SnI₄ was made in the same way by replacing PbI₂ with SnI₂. Heterostructures of [(PEA₂PbI₄)_1−x:(PEA₂SnI₄)_x] were designed by mixing two precursor (PEA₂PbI₄ and PEA₂SnI₄) solutions with alternatively selected high and low volume ratios. All the perovskite films were fabricated by spin coating the precursor solutions on glass slides (1.5 × 1.5 cm²) at 3000 r.p.m. for 30 s, and then thermally annealed at 100 °C for 10 min.