Impact of Cesium/Rubidium Incorporation on the Photophysics of Multiple-Cation Lead Halide Perovskites
Type
ArticleAuthors
Gao, YajunWang, Kai
Wang, Mingcong

Khan, Jafar Iqbal
Balawi, Ahmed

Liu, Wenzhu
De Wolf, Stefaan

Laquai, Frédéric

KAUST Department
KAUST Solar Center (KSC)Material Science and Engineering Program
Physical Science and Engineering (PSE) Division
KAUST Grant Number
OSR-2018-CARF/CCF-3079Date
2020-04-17Online Publication Date
2020-04-17Print Publication Date
2020-06Submitted Date
2020-02-06Permanent link to this record
http://hdl.handle.net/10754/662494
Metadata
Show full item recordAbstract
Incorporating cesium (Cs) or rubidium (Rb) cations into multiple-cation lead mixed-halide perovskites (FA0.83MA0.17Pb(I0.83Br0.17)3) increases their photovoltaic performance. In this study, the fundamental photophysics of perovskites are investigated by steady-state and transient optical spectroscopy and the reasons for the performance increase are revealed. Cs/Rb-cation incorporation slightly increases the bandgap, while exciton binding energies remain in the range of a few meV. Urbach energies are reduced, suggesting improved perovskite microstructure upon Cs/Rb incorporation. Carrier density-induced broadening of the photo-bleaching following the Burstein-Moss model is observed, and the effective carrier masses are determined to be a few tenths of the electron rest mass. From fits of the high-energy tail of the perovskite's photo bleach to Boltzmann's distribution, sub-picosecond hot carrier cooling is revealed, implying strong carrier-phonon coupling. Importantly, the charge carrier recombination dynamics indicate that Cs/Rb-incorporation reduces both the first-order (trap-assisted) and the second-order (radiative) recombination, which appears to be the main reason for the observed performance increase upon Cs/Rb-cation incorporation. Overall, this work presents a detailed study of the photophysics of multiple-cation mixed halide lead perovskites and develops a concise picture of the impact of cesium/rubidium incorporation on the photophysics and device performance.Citation
Gao, Y., Wang, K., Wang, M., Khan, J. I., Balawi, A., Liu, W., … Laquai, F. (2020). Impact of Cesium/Rubidium Incorporation on the Photophysics of Multiple-Cation Lead Halide Perovskites. Solar RRL. doi:10.1002/solr.202000072Sponsors
This publication is based upon work supported by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award No: OSR-2018-CARF/CCF-3079. Yajun Gao and Kai Wang contributed equally to this workPublisher
WileyJournal
Solar RRLAdditional Links
http://doi.wiley.com/10.1002/solr.202000072ae974a485f413a2113503eed53cd6c53
10.1002/solr.202000072