Premium
Direct Observation of Bandgap Oscillations Induced by Optical Phonons in Hybrid Lead Iodide Perovskites
Author(s) -
Guo Peijun,
Xia Yi,
Gong Jue,
Cao Duyen H.,
Li Xiaotong,
Li Xun,
Zhang Qi,
Stoumpos Constantinos C.,
Kirschner Matthew S.,
Wen Haidan,
Prakapenka Vitali B.,
Ketterson John B.,
Martinson Alex B. F.,
Xu Tao,
Kanatzidis Mercouri G.,
Chan Maria K. Y.,
Schaller Richard D.
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201907982
Subject(s) - materials science , phonon , polaron , perovskite (structure) , band gap , iodide , semiconductor , octahedron , molecular vibration , chemical physics , condensed matter physics , spectroscopy , optoelectronics , optics , crystal structure , physics , crystallography , chemistry , inorganic chemistry , electron , quantum mechanics , raman spectroscopy
Abstract Hybrid organic–inorganic perovskites such as methylammonium lead iodide have emerged as promising semiconductors for energy‐relevant applications. The interactions between charge carriers and lattice vibrations, giving rise to polarons, have been invoked to explain some of their extraordinary optoelectronic properties. Here, time‐resolved optical spectroscopy is performed, with off‐resonant pumping and electronic probing, to examine several representative lead iodide perovskites. The temporal oscillations of electronic bandgaps induced by coherent lattice vibrations are reported, which is attributed to antiphase octahedral rotations that dominate in the examined 3D and 2D hybrid perovskites. The off‐resonant pumping scheme permits a simplified observation of changes in the bandgap owing to the A g vibrational mode, which is qualitatively different from vibrational modes of other symmetries and without increased complexity of photogenerated electronic charges. The work demonstrates a strong correlation between the lead–iodide octahedral framework and electronic transitions, and provides further insights into the manipulation of coherent optical phonons and related properties in hybrid perovskites on ultrafast timescales.