Temperature dependent phase transitions and their relation to isosbestic point formation. Case study of C(NH2)3PbI3

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2022-02, Vol.266, p.120462, Article 120462
• Main Authors: Bukleski, M., Dimitrovska-Lazova, S., Aleksovska, S.
• Format: Article
• Language: English
• Subjects: Guanidinium lead iodide; IR and Raman spectra; Isosbestic point; Phase transition
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2021.120462

[Display omitted] •Characterization of phase transitions (PT) in C(NH2)3PbI3 by vibrational spectroscopy.•Discovery of an unambiguity in the low temperature IR spectra, ascribed as a PT.•Defining isostructural phase transition by temperature-induced isosbestic points.•Redefinition of the phases according to the recommendations given by IUCr. Besides the vast research regarding the hybrid organic-inorganic perovskite (HOIP) materials used in the solar cell production, their properties are still not fully uncovered. In this paper, detailed investigation on the phase transitions in guanidinium lead iodide (GAPbI3) using vibrational spectroscopy techniques (IR and Raman) are presented. In addition to the well-known three phases of GAPbI3 (denoted as I, II and III) another one existing in the temperature range from 48 °C to 160 °C is characterized. The thorough inspection of the vibrational spectra revealed some interesting changes occurring in the low temperature region (from −90 to −62 °C) that suggest presence of a new phase. Finally, a redefinition of the phase nomenclature according to the recommendations given by the IUCr is proposed.