Fig. 1
a Raman spectra of a solvent DMF (curve 1) and dissolved in it compounds: 2 - PbI2, 3 - CH3NH3I, 4 - PbI2 and CH3NH3I (1:1), 5 - PbI2 and CH3NH3I (1:2), 6 - PbI2 and CH3NH3I (1:3), 7 - PbI2 and CH3NH3Cl (1:1). b Raman spectra of solutions: 1- PbI2, 2 - PbI2 and CH3NH3I (1:1), 3 - PbI2 and CH3NH3I (1:2), 4 - PbI2 and CH3NH3I (1:3) in DMF in the low-frequency range. All spectra were obtained with λexc = 532 nm at room temperature