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Bottleneck-Free Hot Hole Cooling in CH3NH3PbI3 Revealed by Femtosecond XUV Absorption

preprint
submitted on 25.06.2019 and posted on 26.06.2019 by Max A. Verkamp, Joshua Leveillee, Aastha Sharma, André Schleife, Josh Vura-Weis
Femtosecond carrier cooling in the organohalide perovskite semiconductor CH3NH3PbI3 is measured using extreme ultraviolet (XUV) and optical transient absorption spectroscopy. XUV absorption between 44 eV and 58 eV measures transitions from the I 4d core to the valence and conduction bands and gives distinct signals for hole and electron dynamics. The core-to-valence-band signal directly maps the photoexcited hole distribution and provides a quantitative measurement of the hole temperature. The combination of XUV and optical probes reveals that upon excitation at 400 nm, the initial hole distribution is 3.5 times hotter than the electron distribution. At an initial carrier density of 1.4×1020 cm-3 both carriers are subject to a hot phonon bottleneck, but at 4.2×1019 cm-3 the holes cool to less than 1000 K within 400 fs. This result places significant constraints on the use of organohalide perovskites in hot-carrier photovoltaics.

Funding

AFOSR FA9550-14-1-0314

AFOSR FA9550-18-1-0293

NSF DMR-1555153

NSF OCI-0725070

NSF ACI-1238993

History

Email Address of Submitting Author

vuraweis@illinois.edu

Institution

University of Illinois at Urbana-Champaign

Country

USA

ORCID For Submitting Author

0000-0001-7734-3130

Declaration of Conflict of Interest

None

Exports