%0 Journal Article %1 doi:10.1021/acsenergylett.7b00790 %A Guo, Peijun %A Xia, Yi %A Gong, Jue %A Stoumpos, Constantinos C. %A McCall, Kyle M. %A Alexander, Grant C. B. %A Ma, Zhiyuan %A Zhou, Hua %A Gosztola, David J. %A Ketterson, John B. %A Kanatzidis, Mercouri G. %A Xu, Tao %A Chan, Maria K. Y. %A Schaller, Richard D. %D 0 %J ACS Energy Letters %K acoustic fluctuations perovskite phonon polar %N 0 %P 2463-2469 %R 10.1021/acsenergylett.7b00790 %T Polar Fluctuations in Metal Halide Perovskites Uncovered by Acoustic Phonon Anomalies %U http://dx.doi.org/10.1021/acsenergylett.7b00790 %V 0 %X 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.

@article{doi:10.1021/acsenergylett.7b00790, abstract = { 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. }, added-at = {2017-10-04T10:48:11.000+0200}, author = {Guo, Peijun and Xia, Yi and Gong, Jue and Stoumpos, Constantinos C. and McCall, Kyle M. and Alexander, Grant C. B. and Ma, Zhiyuan and Zhou, Hua and Gosztola, David J. and Ketterson, John B. and Kanatzidis, Mercouri G. and Xu, Tao and Chan, Maria K. Y. and Schaller, Richard D.}, biburl = {https://www.bibsonomy.org/bibtex/2e8eff06019108e005d76e86bd7d4c8d4/fabianopkm}, description = {Polar Fluctuations in Metal Halide Perovskites Uncovered by Acoustic Phonon Anomalies - ACS Energy Letters (ACS Publications)}, doi = {10.1021/acsenergylett.7b00790}, eprint = {http://dx.doi.org/10.1021/acsenergylett.7b00790}, interhash = {0086aa3963ee6ee1ac16c09cde30e376}, intrahash = {e8eff06019108e005d76e86bd7d4c8d4}, journal = {ACS Energy Letters}, keywords = {acoustic fluctuations perovskite phonon polar}, number = 0, pages = {2463-2469}, timestamp = {2017-10-04T10:48:11.000+0200}, title = {Polar Fluctuations in Metal Halide Perovskites Uncovered by Acoustic Phonon Anomalies}, url = {http://dx.doi.org/10.1021/acsenergylett.7b00790}, volume = 0, year = 0 }