RAMAN-SPECTROSCOPY OF NEW LEAD IODIDE INTERCALATION COMPOUNDS

PbI2 crystals have been intercalated with ammonia, methylamine (CH3NH2), ethylamine (C2H5NH2), and butylamine (C4H9NH2) for the first time. Raman spectra of these materials, and also of PbI2 intercalated with nonylamine (C9H19NH2) were obtained using an excitation wavelength of 514.531 nm. For comparison a study of the interaction of CdI2 with the same molecules is included. Raman spectroscopy in the range 10-500 cm-1 demonstrated the occurrence of a polytypic phase transition from IT to 3T on intercalation of PbI2 and also that intercalation results in the breaking up of the crystal into many small crystallites. The existence of strong Pb-N interactions was demonstrated by both infrared and Raman spectroscopy.