Starting materials: S-2-MeBA, PbBr2, HI, dimethylformamide (DMF), dichloromethane (DCM), ethyl ether

Product: yellow flaky single crystals (S-2-MeBA)2PbBr4

Description: Add (S-2-MeBA) (0.25 mmol) and PbBr2 (0.125 mmol) to 0.8 mL of an aqueous HI solution. Obtain a clear solution at 95 degrees Celsius, then cool to room temperature at a rate of 2 degrees Celsius per hour. The cooling process yields about 0.07 grams of (S-2-MeBA)2PbBr4 crystals. Then, dissolve 0.03 g of the obtained crystals in dimethylformamide (DMF) (0.8 mol/L) in a small uncovered vial, and place it in a larger vial holding dichloromethane (DCM). Over a week-long period, the DCM vapors diffuse into the vial with the DMF solution and produce yellow flaky single crystals ((S-2-MeBA)2PbBr4) as well as S-2-MeBA salt, light-yellow needle-shaped crystals. The crystals were filtered, washed with ethyl ether, and vacuum-dried. The (S-2-MeBA)2PbBr4 crystals can be separated from the salt crystals under a microscope, and they were then used for single-crystal X-ray diffraction (SC-XRD).

Comment: Differential scanning calorimetry (DSC): A TA Discovery DSC 2500 was used to carry out low-temperature conventional differential scanning calorimetry (DSC) measurements. The instrument was under helium purge with a 5 K/min ramp from 298 K to 124 K and back to 298 K (with use of an LN2P cooler). Sample powder was loaded into a Tzero Hermetic aluminum pan, with temperature and enthalpy calibrated in advance. A similar instrument was used to perform high-temperature DSC measurements under nitrogen purge. The ramp rate was 5 K/min from 298 K to 603 K. An aluminum pan was hermetically sealed to contain samples.

Method: Differential scanning calorimetry (DSC)

Description: A TA Discovery DSC 2500 was used to carry out low-temperature conventional differential scanning calorimetry (DSC) measurements. The instrument was under helium purge with a 5 K/min ramp from 298 K to 124 K and back to 298 K (with use of an LN2P cooler). Sample powder was loaded into a Tzero Hermetic aluminum pan, with temperature and enthalpy calibrated in advance. A similar instrument was used to perform high-temperature DSC measurements under nitrogen purge. The ramp rate was 5 K/min from 298 K to 603 K. An aluminum pan was hermetically sealed to contain samples.