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Published January 7, 2016 | public
Journal Article

Phonon Mode Transformation Across the Orthohombic-Tetragonal Phase Transition in a Lead Iodide Perovskite CH_3NH_3PbI_3: A Terahertz Time-Domain Spectroscopy Approach

Abstract

We study the temperature-dependent phonon modes of the organometallic lead iodide perovskite CH_3NH_3PbI_3 thin film across the terahertz (0.5–3 THz) and temperature (20–300 K) ranges. These modes are related to the vibration of the Pb–I bonds. We found that two phonon modes in the tetragonal phase at room temperature split into four modes in the low-temperature orthorhombic phase. By use of the Lorentz model fitting, we analyze the critical behavior of this phase transition. The carrier mobility values calculated from the low-temperature phonon mode frequencies, via two theoretical approaches, are found to agree reasonably with the experimental value (∼2000 cm^2 V^(–1) s^(–1)) from a previous time-resolved THz spectroscopy work. Thus, we have established a possible link between terahertz phonon modes and the transport properties of perovskite-based solar cells.

Additional Information

© 2015 American Chemical Society. Received 6 October 2015; Accepted 3 December 2015; Published online 3 December 2015; Published in print 7 January 2016. We acknowledge useful discussions with Aron Walsh (Department of Chemistry, University of Bath). C.L. acknowledges the support from the Theoretical and Computational Science (TaCS) Center. D.M.Z. acknowledges support from TUM-CREATE. E.E.M.C. acknowledges support from Singapore Ministry of Education AcRF Tier 1 (RG13/12 and RG123/14). R.A.M. thanks the ONR and ARO for their support. M.-E.M.-B. is grateful to the Nanyang Technological University for supporting the Biophysics Center. T.A. and J.-X.Z. acknowledge the support from the LANL LDRD Program. The work was supported in part by the Center for Integrated Nanotechnologies, a U.S. DOE BES user facility.

Additional details

Created:
August 20, 2023
Modified:
October 25, 2023