| Initial crystal system | orthorhombic |
| Final crystal system | tetragonal |
| Initial space group | Pnma |
| Final space group | I4/mcm |
| Direction | Unknown |
| Phase transition temperature | 152.0 K |
Hysteresis: NIL
Starting materials: HI (Sigma Aldrich), methylamine, PbI2 (99%, Sigma Aldrich), gamma-butyrolactone (Sigma Aldrich)
Product: Black MAPbI3 Single crystals
Description: MAPbI3 was synthesized using the method described by [2]. Make MAI by reacting a concentrated aqueous solution of hydroiodic acid with methylamine (40% in methanol) at 0 °C for 2 h with constant stirring. Evaporate at 50 °C in a rotary evaporator and wash the resulting precipitant three times with ethyl ether and dry in a vacuum at 60 °C for 24 h. Equimolar mixtures of the as-synthesised MAI and PbI2 in gamma-butyrolactone were left to stir overnight at 60 °C. The MAPbI3 product was obtained by drop-casting the as-prepared solutions on to glass substrates, which were then heated to 100 °C and annealed for 30 min. Crystalline MAPbI3 was recovered from the glass after cooling.
Comment: Synthesis references: [1] A. Poglitsch and D. Weber, J. Chem. Phys., 1987, 87, 6373–6378. [2] J. H. Im, C. R. Lee, J. W. Lee, S. W. Park and N. G. Park, Nanoscale, 2011, 3, 4088–4093.
Method: Single crystal X-ray diffraction
Description: A small fragment (approximately 0.1 mm X 0.1 mm X 0.1 mm) was cleaved from one of the solution grown single crystals. Data were collected on a Bruker Smart Apex II three-circle diffractometer at various temperatures between room temperature and 100 K using Mo Ka radiation with a graphite monochromator over the angular range 2.5 to 30.5 ° 2\theta. Refer to Page 5637 Figure 11.
Comment: Author did not formally state 152 K as the transition temperature. But lattice parameters provided in Table 8 supports this conclusion.