Starting materials: distilled HI (aqueous 99.95%), H3PO2 (50% aqueous), SnCl2·2H2O (98%), CH3NH3Cl (98%), CH3(CH2)3NH2
Product: cherry-red rectangular plates
Description: Two-necked flask was charged with aqueous HI (6.8 mL, 7.58 M) and aqueous H3PO2 (1.7 mL, 9.14 M). Nitrogen was passed through the liquid to degass the solution. SnCl2•2H2O powder (2256 mg, 10 mmol) was dissolved in a solution of 57% (w/w) aqueous HI solution (20 mL, 152 mmol) and 50% aqueous H3PO2 (3.4 mL, 31 mmol) by boiling the solution and constantly stirring. This formed a bright yellow solution. Solid CH3(CH2)3NH2 (694 μL, 7 mmol) was neutralized with 57% (w/w) HI (5 mL38 mmol) via an ice bath. This resulted in a clear pale-yellow solution. CH3(CH2)3NH3I solution was added to SnI2 solution and produced a black precipitate. After the solution was boiled, stirring stopped, the solution cooled, and crystals formed for 2 hours.
Method: UV-vis absorption (diffuse reflectance)
Description: Diffuse-reflectance measurements were performed and collected at room temperature. A Shimadzu UV-3600 PC double-beam and double monochromator spectrophotometer (operating between 200 to 2500 nm) was used.BaSO4 was used as a nonabsorbing reflectance reference.
Starting materials: BAI, MAI, SnI2, HI, H3PO2
Product: Single crystals of 2D tin halide perovskites
Description: Single crystals synthesized by slow cooling method. Growth solution prepared with 0.43mmol BAI, 0.2mmol MAI, 0.59mmol SnI2, 1mL HI, and 0.1mL H3PO2 in a sealed glass vial and placed in a muffle furnace and heated until completely dissolved. Solution cooled to room temperature at a rate of 2°C/hour. Crystals were then dried and stored in a nitrogen glove box.
Method: UV-Vis absorption
Description: UV-vis absorption spectra collected by CRAIC 20/30PV Pro instrument. Transmission (T) and reflection (R) spectra collected at the same location. abs. = -log[T/(1-R)] used to transform relationship between absorption spectrum and wavelength.