Synthesis, vibrational and optical properties of a new three-layered organic-inorganic perovskite (C4H9NH3)4Pb3I4Br6

An organic-inorganic hybrid perovskite (C4H9NH3)(4)Pb3I4Br6 Was synthesized and studied by X-ray diffraction, Raman and infrared spectroscopies, optical transmission and photoluminescence. The title compound, abbreviated (C-4)(4)Pb3I4Br6, crystallises in a periodic two-dimensional multilayer structure with P2(1)/a space group. The structure is built up from alternating inorganic and organic layers. Each inorganic layer consists of three sheets of PbX6 (X = I, Br) octahedra. Raman and infrared spectra of the title compound were recorded in the 100-3500 and 400-4000 cm(-1) frequency ranges, respectively. An assignment of the observed vibration modes is reported. Optical transmission measurements, performed on thin films of (C-4)(4)Pb3I4Br6, revealed two absorption bands at 474 and 508 nm. Photoluminescence measurements have shown a green emission peak at 519 nm. (C) 2009 Elsevier B.V. All rights reserved.