TY - JOUR
T1 - Polar Fluctuations in Metal Halide Perovskites Uncovered by Acoustic Phonon Anomalies
AU - Guo, Peijun
AU - Xia, Yi
AU - Gong, Jue
AU - Stoumpos, Konstantinos
AU - McCall, Kyle M.
AU - Alexander, Grant C.B.
AU - Ma, Zhiyuan
AU - Zhou, Hua
AU - Gosztola, David J.
AU - Ketterson, John B
AU - Kanatzidis, Mercouri
AU - Xu, Tao
AU - Chan, Maria K.Y.
AU - Schaller, Richard Daniel
N1 - Funding Information:
The work was performed at the Center for Nanoscale Materials, a U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences User Facility under Contract No. DE-AC02-06CH11357. T.X. acknowledges financial support from the U.S. National Science Foundation (CBET-1150617). Work at Northwestern University was supported by Grant SC0012541 from the U.S. Department of Energy, Office of Science (samples synthesis, purification and characterization). Use of the Advanced Photon Source, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. We thank Dr. Benjamin T. Diroll and Dr. Matthew E. Sykes for assistance in transient absorption measurements.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/10/13
Y1 - 2017/10/13
N2 - Solution-processable metal halide perovskites (MHPs) offer great promise for efficient light-harvesting and -emitting devices because of their long carrier lifetime and superior carrier transport properties. Similar to traditional oxide perovskites, MHPs exhibit strong dynamic disorders that may further impact their electronic properties. Here we investigate the coherent acoustic phonons of inorganic and organic-inorganic (hybrid) MHP single crystals (CsPbCl3, MAPbCl3, CsPbBr3, MAPbBr3, FAPbBr3, MAPbI3, and FAPbI3) using pump-probe reflection spectroscopy. We show significant phonon softening in the cubic phase of all compositions close to the cubic-to-tetragonal phase transition temperature. Such phonon softening in conjunction with strong acoustic damping is attributed to pretransitional polar fluctuations. Comparison of MHPs with different compositions show that the degree of pretransitional fluctuations is correlated with the size rather than the dipole moment of the A-site cations, and further with the size of the anions.
AB - Solution-processable metal halide perovskites (MHPs) offer great promise for efficient light-harvesting and -emitting devices because of their long carrier lifetime and superior carrier transport properties. Similar to traditional oxide perovskites, MHPs exhibit strong dynamic disorders that may further impact their electronic properties. Here we investigate the coherent acoustic phonons of inorganic and organic-inorganic (hybrid) MHP single crystals (CsPbCl3, MAPbCl3, CsPbBr3, MAPbBr3, FAPbBr3, MAPbI3, and FAPbI3) using pump-probe reflection spectroscopy. We show significant phonon softening in the cubic phase of all compositions close to the cubic-to-tetragonal phase transition temperature. Such phonon softening in conjunction with strong acoustic damping is attributed to pretransitional polar fluctuations. Comparison of MHPs with different compositions show that the degree of pretransitional fluctuations is correlated with the size rather than the dipole moment of the A-site cations, and further with the size of the anions.
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U2 - 10.1021/acsenergylett.7b00790
DO - 10.1021/acsenergylett.7b00790
M3 - Article
AN - SCOPUS:85031303346
SN - 2380-8195
VL - 2
SP - 2463
EP - 2469
JO - ACS Energy Letters
JF - ACS Energy Letters
IS - 10
ER -
