Crystal system: monoclinic
| Exciton binding energy, meV |
|---|
Starting materials: PbI2, HI(47%), butanolamine (HOC4H8NH2), ethyl acetate
Product: Yellow crystals of bis(4-iodobutylammonium) lead iodide
Description: PbI2 (0.178 mmol; 0.082 g) was dissolved in 1 mL HI solution. Then HOC4H8NH2 (0.449 mmol; 0.040 g) was added. The precipitate was dissolved at 3 mL ethyl acetate and was kept undisturbed at room temperature. It is assumed that there was a substitution reaction that took place where the amine had an alcohol group substituted with an iodide atom.
Method: Reflectance spectroscopy
Description: Powder samples of BIA2PbI4 were tested for absorption. Linear absorption was determined through UV-vis reflection. A Ti:sapphire laser amplifier (Coherent Astrella, 800 nm, pulse duration about 60 fs, about 5 mJ/pulse) was used to test the powder sample.
Comment: A 2D Elliot formula was used to generate an exciton fit for this data. The formula can be found in the supporting information of the reference publication. The exciton binding energy was determined to be about 150 meV.