Starting materials: lead iodide (PbI2), hydroiodic acid (HI, 57% w/w aqueous, stabilized with H3PO2), ethanolamine (EOA), diethyl ether
Product: Red single crystals (EOA2PbI4)
Description: PbI2 (0.16 g, 0.35 mmol) is dissolved in HI solution (1 mL). Then, EOA (80 μL, 1.3 mmol) is added. This solution is sonicated at room temperature for five minutes. It is then kept at 3 °C in a fridge. Later, red single crystals can be filtered and washed with diethyl ether. They are vacuum dried overnight.
Method: Diffuse reflectance spectroscopy
Description: Powder samples of EOA2PbI4 were used to measure absorption. Linear absorptions can be determined from measurements of UV-vis reflection.
Comment: A 2D Elliot formula was used to create a fit for the data. This formula can be found in the supporting information of the referenced publication and the files attached to this dataset. The formula can extract the exciton binding energy of this material. The analysis yields an exciton binding energy of ≈ 46 meV.