Raman spectroscopy of organic-inorganic halide perovskites

0448052 - FZÚ 2016 RIV US eng J - Journal Article
Ledinský, Martin - Löper, P. - Niesen, B. - Holovský, Jakub - Moon, S.J. - Yum, J. H. - De Wolf, S. - Fejfar, Antonín - Ballif, C.
Raman spectroscopy of organic-inorganic halide perovskites.
Journal of Physical Chemistry Letters. Roč. 6, č. 3 (2015), 401-406. ISSN 1948-7185
R&D Projects: GA ČR GA14-15357S; GA MŠMT(CZ) LM2011026
Institutional support: RVO:68378271
Keywords : mixed iodide and bromide lead perovskites * micro-Raman mapping * local chemical sensitivity * moisture-induced degradation * lead iodide * photoluminesce
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 8.539, year: 2015

Micro-Raman spectroscopy provides laterally resolved microstructural information for a broad range of materials. In this Letter, we apply this technique to tri-iodide (CH3NH3PbI3), tribromide (CH3NH3PbBr3), and mixed iodide–bromide (CH3NH3PbI3–xBrx) organic–inorganic halide perovskite thin films and discuss necessary conditions to obtain reliable data. We explain how to measure Raman spectra of pristine CH3NH3PbI3 layers and discuss the distinct Raman bands that develop during moisture-induced degradation. We also prove unambiguously that the final degradation products contain pure PbI2. Moreover, we describe CH3NH3PbI3–xBrx Raman spectra and discuss how the perovskite crystallographic symmetries affect the Raman band intensities and spectral shapes. On the basis of the dependence of the Raman shift on the iodide-to-bromide ratio, we show that Raman spectroscopy is a fast and nondestructive method for the evaluation of the relative iodide-to-bromide ratio.
Permanent Link: http://hdl.handle.net/11104/0249784