Confinement and Exciton Binding Energy Effects on Hot Carrier Cooling in Lead Halide Perovskite Nanomaterials

Ben P. Carwithen, Thomas R. Hopper, Ziyuan Ge, Navendu Mondal, Tong Wang, Rozana Mazlumian, Xijia Zheng, Franziska Krieg, Federico Montanarella, Georgian Nedelcu, Martin Kroll, Miguel Albaladejo Siguan, Jarvist M. Frost, Karl Leo, Yana Vaynzof, Maryna I. Bodnarchuk, Maksym V. Kovalenko, Artem A. Bakulin*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

26 Citations (Scopus)
61 Downloads (Pure)

Abstract

The relaxation of the above-gap (“hot”) carriers in lead halide perovskites (LHPs) is important for applications in photovoltaics and offers insights into carrier-carrier and carrier-phonon interactions. However, the role of quantum confinement in the hot carrier dynamics of nanosystems is still disputed. Here, we devise a single approach, ultrafast pump-push-probe spectroscopy, to study carrier cooling in six different size-controlled LHP nanomaterials. In cuboidal nanocrystals, we observe only a weak size effect on the cooling dynamics. In contrast, two-dimensional systems show suppression of the hot phonon bottleneck effect common in bulk perovskites. The proposed kinetic model describes the intrinsic and density-dependent cooling times accurately in all studied perovskite systems using only carrier-carrier, carrier-phonon, and excitonic coupling constants. This highlights the impact of exciton formation on carrier cooling and promotes dimensional confinement as a tool for engineering carrier-phonon and carrier-carrier interactions in LHP optoelectronic materials.

Original languageEnglish
Pages (from-to)6638-6648
Number of pages11
JournalAcs Nano
Volume17
Issue number7
DOIs
Publication statusPublished - 11-Apr-2023

Keywords

  • hot carriers
  • nanocrystals
  • nanoplatelets
  • two-dimensional perovskites
  • ultrafast spectroscopy

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