Ultrafast photo-induced enhancement of electron-phonon coupling in metal-halide perovskites
Type
PreprintKAUST Department
Material Science and Engineering ProgramKAUST Solar Center (KSC)
Physical Science and Engineering (PSE) Division
King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), Thuwal 23955-6900, Kingdom of Saudi Arabia
Date
2021-02-15Permanent link to this record
http://hdl.handle.net/10754/667477
Metadata
Show full item recordAbstract
Abstract In metal-halide perovskites (MHPs), the nature of organic cations affects both, the perovskite’s structure and its optoelectronic properties. Using ultrafast pump-probe spectroscopy, we demonstrate that in state-of-the-art mixed-cation MHPs ultrafast photo-induced bandgap narrowing occurs, and linearly depends on the excited carrier density in the range from 10$^{16}$ cm$^{− 3}$ to above 10$^{18}$ cm$^{− 3}$. Furthermore, time-domain terahertz (td-THz) photoconductivity measurements reveal that the majority of carriers are localized and that the localization increases with the carrier density. Both observations, the bandgap narrowing and carrier localization, can be rationalized by ultrafast (sub-2ps) photo-induced enhancement of electron-phonon coupling, originating from dynamic disorder, as clearly evidenced by the presence of a Debye relaxation component in the terahertz photoconductivity spectra. The observation of photo-induced enhancement of electron-phonon coupling and dynamic disorder not only provides specific insight into the polaron-strain distribution of excited states in MHPs, but also adds to the development of a concise picture of the ultrafast physics of this important class of semiconductors.Citation
Laquai, F., Wang, M., Gao, Y., Wang, K., & Wolf, S. D. (2021). Ultrafast photo-induced enhancement of electron-phonon coupling in metal-halide perovskites. doi:10.21203/rs.3.rs-228859/v1Publisher
Research SquareAdditional Links
https://www.researchsquare.com/article/rs-228859/v1ae974a485f413a2113503eed53cd6c53
10.21203/rs.3.rs-228859/v1
Scopus Count
Except where otherwise noted, this item's license is described as Archived with thanks to Research Square