See all entries for this property (20 total)
| Initial crystal system | tetragonal |
| Final crystal system | orthorhombic |
| Initial space group | Unknown |
| Final space group | Unknown |
| Direction | Cooling |
| Phase transition temperature | 160.0 K |
Hysteresis: 10
Starting materials: MAI, PbI2, DMF, Si glass
Product: MAPbI3 Thin-film on Si
Description: Dissolve methylammonium iodide and lead (II) iodide (Sigma-Aldrich) in anhydrous N,N-Dimethylformamide (DMF) at a 3:1 molar ratio of MAI to PbI2, with final concentrations of 2.64M methylammonium iodide. The perovskite layer was then formed by spin coating the precursor solutions directly on the glass substrate at 2,000 r.p.m. in air. The flat and thin meso samples were spin coated without dilution but mesoporous samples were spin coated from diluted (three parts in four) precursor solutions. After spin coating, anneal the CH3NH3PbI3 at 150°C for 15 min.
Method: UV-Vis absorption
Description: Absorption measurements were performed using a spectrophotometer (Perkin Elmer Lambda 1050) and a continuous flow static exchange gas cryostat (Oxford Instruments Optistat CF). The cryostat consist of three chambers, one inside the other. The sample is housed inside the internal chamber filled with gaseous He. The cryogenic liquid (He) is fluxed inside the second chamber allowing temperature control of the He atmosphere of the sample chamber. Eventually, a third chamber is evacuated (~10^-5–10^-6 mbar) in order to assure thermal isolation from the external ambient. Refer to Fig. 1.
Comment: Crystal sizes larger than 500nm