Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), hexylamine 99%, H3PO2 (50 wt. % in H2O)
Product: orange plate-like crystals
Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. 1000 μL (7.52 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature.
Comment: Note that the n=1 C6N1 compound is specifically mentioned as crystallizing in an orthorhombic spacegroup in the reference, with associated PXRD data shown in Figure S10. In contrast, the n>1 C6N1 compounds crystallize in a monoclinic spacegroup.
Method: UV-vis absorption (diffused reflectance)
Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R.
Starting materials: C6H16N, HI, PbI2, EtO2
Product: Thin film of (C12H25NH3)2PbI4
Description: Prepare hexylammonium iodide salts via neutralization of HI with HA. Remove unreacted species by evaporation. Purify product by recrystallization in minimal diethyl ether/excess hexane and isolate via vacuum filtration. Prepare films by spin-coating or drop-casting solutions (prepared by dissolving HAI and PbI2 powders at a 2.5:1 molar ratio in a 1:0.34 volume ratio mixture of THF and methanol). Spin-coat films from solutions of 20 mg/mL at 2000 rpm for 30 s and anneal for 15 min at 70 °C.
Method: UV-Vis absorption
Description: Steady-state room-temperature absorption spectra were determined by placing spin-coated films on glass in a using an HP 8453 spectrometer.