CH₃NH₃PbI₃, A Potential Solar Cell Candidate: Structural and Spectroscopic Investigations

Hybrid organic-inorganic metal halides of the type CH₃NH₃PbX₃ have emerged as potential materials for photovoltaic applications. In this paper we discuss structural, electronic, and optical spectroscopy investigations performed on high quality single crystals of CH₃NH₃PbI₃. Our results conclusively suggest that CH₃NH₃PbI₃ crystallizes in centrosymmetric space group and the methylammonium moiety exhibits disordered packing at room temperature. Extracted values of the exciton binding energy, the electron-phonon coupling constant, and the schematic energy level diagram constructed from the emission broadening, Raman, and photoemission spectroscopy measurements clearly show the potential of this system in photovoltaic applications.