Ultrafast exciton many-body interactions and hot-phonon bottleneck in colloidal cesium lead halide perovskite nanocrystals

Anirban Mondal, J. Aneesh, Vikash Kumar Ravi, Rituraj Sharma, Wasim J. Mir, Mathew C. Beard, Angshuman Nag, K. V. Adarsh*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

97 Scopus citations

Abstract

Defect-tolerant perovskite nanocrystals of the general formula Cs-Pb-X3 (where X=Cl, Br, and I) have shown exceptional potential in fundamental physics as well as in novel optoelectronic applications as the next generation of solar cells. Although exciton many-body interactions such as biexciton Stark shift, state filling, and Auger recombination are studied extensively, other important correlated effects, such as band gap renormalization (BGR) and hot-phonon bottleneck, are not explored in these nanocrystals. Here we experimentally demonstrate the carrier density dependence of the BGR and an effective hot-phonon bottleneck in CsPb(Cl0.20Br0.80)3 mixed-halide nanocrystals. The results are compared with two other halide compositions, namely, CsPbBr3 and CsPb(Br0.55I0.45)3 nanocrystals with varying band gaps. The optical response of the nanocrystals changes dramatically across the spectral range of many hundreds of meV at high carrier density due to large BGR. We have calculated the BGR constant ≈(6.0±0.3)×10-8eV cm for CsPb(Cl0.20Br0.80)3 nanocrystals that provides the amount of band gap shift as a function of carrier density. In these nanocrystals, an efficient hot-phonon bottleneck is observed at a carrier density of 3.1×1017cm-3 that slows down the thermalization by 1 order of magnitude. Our findings reveal that the complex kinetic profile of the exciton dynamics can be analyzed by the global target analysis using the sequential model with increasing lifetimes.

Original languageEnglish (US)
Article number115418
JournalPhysical Review B
Volume98
Issue number11
DOIs
StatePublished - Sep 10 2018

Bibliographical note

Funding Information:
The authors gratefully acknowledge the Department of Science and Technology (Project No. EMR/2016/002520) and DAE-BRNS (Project No. 37(3)/14/26/2016-BRNS/37245) for financial support. V.K.S. and W.J.M. acknowledge IISER, Pune, and CSIR, Government of India, respectively, for research fellowships. K.V.A gratefully acknowledges the DST-IUSSTF BASE fellowship. J.A gratefully acknowledges the SERB NPDF fellowship (Sanction Order No. PDF/2017/002048). M.C.B. acknowledges support as part of the Center for Hybrid Organic Inorganic Semiconductors for Energy (CHOISE) an Energy Frontier Research Center funded through the Office of Basic Energy Sciences, Office of Science within the US Department of Energy (DOE). Support to the National Renewable Energy Laboratory was provided by the DOE under Contract No. DE-AC36-08GO28308.

Funding Information:
The authors gratefully acknowledge the Department of Science and Technology (Project No. EMR/2016/002520) and DAE-BRNS (Project No. 37(3)/14/26/2016-BRNS/37245) for financial support. V.K.S. and W.J.M. acknowledge IISER, Pune, and CSIR, Government of India, respectively, for research fellowships. K.V.A gratefully acknowledges the DST-IUSSTF BASE fellowship. J.A gratefully acknowledges the SERB NPDF fellowship (Sanction Order No. PDF/2017/002048). M.C.B. acknowledges support as part of the Center for Hybrid Organic Inorganic Semiconductors for Energy (CHOISE) an Energy Frontier Research Center funded through the Office of Basic Energy Sciences, Office of Science within the US Department of Energy (DOE). Support to the National Renewable Energy Laboratory was provided by the DOE under Contract No. DE-AC36-08GO28308. The views expressed in the article do not necessarily represent the views of the DOE or the US Government. The US Government retains and the publisher, by accepting the article for publication, acknowledges that the US Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for US Government purposes.

Publisher Copyright:
© 2018 American Physical Society. US.

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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