By means of non-resonant Raman spectroscopy and density functional theory calculations, we measure and assign the vibrational spectrum of two distinct two-dimensional lead-iodide perovskite derivatives. These two samples are selected in order to probe the effects of the organic cation on lattice dynamics. One templating cation is composed of a phenyl-substituted ammonium derivative, while the other contains a linear alkyl group. We find that modes that directly involve the organic cation are more prevalent in the phenyl-substituted derivative. Comparison of the temperature dependence of the Raman spectra reveals differences in the nature of dynamic disorder, with a strong dependence on the molecular nature of the organic moiety.
@article{arxiv.1812.05255,
title = {Lattice vibrations and dynamic disorder in two-dimensional hybrid lead-halide perovskites},
author = {Vlad Alexandru Dragomir and Stefanie Neutzner and Claudio Quarti and Daniele Cortecchia and Annamaria Petrozza and Sjoerd Roorda and David Beljonne and Richard Leonelli and Ajay Ram Srimath Kandada and Carlos Silva},
journal= {arXiv preprint arXiv:1812.05255},
year = {2018}
}