Bond polarizability as a probe of local crystal fields in hybrid lead-halide perovskites
arXiv:2304.14198 · doi:10.1021/acs.jpclett.3c01158
Abstract
A rotating organic cation and a dynamically disordered soft inorganic cage are the hallmark features of hybrid organic-inorganic lead-halide perovskites. Understanding the interplay between these two subsystems is a challenging problem but it is this coupling that is widely conjectured to be responsible for the unique behavior of photo-carriers in these materials. In this work, we use the fact that the polarizability of the organic cation strongly depends on the ambient electrostatic environment to put the molecule forward as a sensitive probe of local crystal fields inside the lattice cell. We measure the average polarizability of the C/N--H bond stretching mode by means of infrared spectroscopy, which allows us to deduce the character of the motion of the cation molecule, find the magnitude of the local crystal field and place an estimate on the strength of the hydrogen bond between the hydrogen and halide atoms. Our results pave the way for understanding electric fields in lead-halide perovskites using infrared bond spectroscopy.
arXiv commentversion accepted for publication in The Journal of Physical Chemistry Letters
References in corpus (10)
- Atomistic origins of high-performance in hybrid halide perovskite solar cells
- Local polar fluctuations in lead halide perovskite crystals
- Dynamic disorder, phonon lifetimes, and the assignment of modes to the vibrational spectra of methylammonium lead halide perovskites
- Elastic softness of hybrid lead halide perovskites
- Perspective: Theory and simulation of hybrid halide perovskites
- Direct evidence of weakly dispersed and strongly anharmonic optical phonons in hybrid perovskites
- Infrared Spectroscopic Study of Vibrational Modes across the Orthorhombic-Tetragonal Phase Transition in Methylammonium Lead Halide Single Crystals
- Common acoustic phonon lifetimes in inorganic and hybrid lead halide perovskites
- Spin-Electric Coupling in Lead Halide Perovskites
- Rotor Lattice Model of Ferroelectric Large Polarons