1. Critical Role of Methylammonium Librational Motion in Methylammonium Lead Iodide (CH3NH3PbI3) Perovskite Photochemistry
- Author
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Richard A. Mathies, Minliang Lai, Jeffrey B. Neaton, Myeongkee Park, Nikolay Kornienko, Peidong Yang, and Sebastian E. Reyes-Lillo
- Subjects
chemistry.chemical_classification ,Photoluminescence ,Hydrogen bond ,Chemistry ,Mechanical Engineering ,Iodide ,Bioengineering ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,symbols.namesake ,Octahedron ,symbols ,General Materials Science ,0210 nano-technology ,Raman spectroscopy ,Spectroscopy ,Perovskite (structure) - Abstract
Raman and photoluminescence (PL) spectroscopy are used to investigate dynamic structure–function relationships in methylammonium lead iodide (MAPbI3) perovskite. The intensity of the 150 cm–1 methylammonium (MA) librational Raman mode is found to be correlated with PL intensities in microstructures of MAPbI3. Because of the strong hydrogen bond between hydrogens in MA and iodine in the PbI6 perovskite octahedra, the Raman activity of MA is very sensitive to structural distortions of the inorganic framework. The structural distortions directly influence PL intensities, which in turn have been correlated with microstructure quality. Our measurements, supported with first-principles calculations, indicate how excited-state MA librational displacements mechanistically control PL efficiency and lifetime in MAPbI3—material parameters that are likely important for efficient photovoltaic devices.
- Published
- 2017