Observation of 3D Biexcitons in Pristine-Quality CH3NH3PbBr3 Single Crystals

Hongsun Ryu, Jeehong Park, Seo Hyun Nam, Joon Woo Park, Kitae Kim, Yeonjin Yi, Joon I. Jang

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4 Citations (Scopus)


Halide perovskites (HPs) are fascinating materials whose optoelectronic properties are arguably excitonic. In the HP family, biexcitons are known to exist only in low dimensions where exciton–exciton binding is strongly enhanced by quantum and dielectric confinements. In this paper, however, it is shown that they indeed do exist in 3D bulk CH3NH3PbBr3 (MAPbBr3) single crystals if the pristine crystal quality is ensured for subtle binding of two excitons. The existence of biexcitons is clearly evidenced below 30 K with a binding energy of ≈3.9 ± 0.3 meV according to i) exciton–biexciton population dynamics, ii) giant resonant two-photon excitation of biexcitons, iii) inverted Boltzmann-type spectral feature, and iv) zero degree of circular polarization in the biexciton photoluminescence. Because of the polariton effect, the two-photon resonance occurs at the excited biexciton state from which longitudinal-transverse splitting is calculated to be 3.7 meV. The discovery of the 3D biexcitons underscores the very quality of HP crystals for generating various many-body excitonic phases in MAPbBr3 and its analogues toward the improved understanding of their fundamental properties and highly efficient optoelectronic applications.

Original languageEnglish
Article number2107882
JournalAdvanced Materials
Issue number12
Publication statusPublished - 2022 Mar 24

Bibliographical note

Publisher Copyright:
© 2022 Wiley-VCH GmbH.

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering


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