Pressure-induced Phase Changes in Cesium Lead Bromide Perovskite Nanocrystals with Planar Defects

ORAL

Abstract

Lead halide perovskites have a rich landscape of structural and optical properties, which can be explored and possibly controlled by applying high pressure. CsPbBr3 NCs with Ruddlesden-Popper (RP) faults, formed via post-synthetic fusion growth, are significantly larger in size than as-synthesized NCs and display exceptional emission stability. We compare synchrotron-based high pressure X-ray diffraction and photoluminescence (PL) properties of CsPbBr3 (without RP) and RP-CsPbBr3 (with RP), and resolve their crystal structure under pressure for the first time. CsPbBr3 undergoes a phase transition from ambient orthorhombic (S.G: Pnma) to cubic (S.G: Pm-3m) phase at 1.7 GPa and RP-CsPbBr3 transforms from Pnma to monoclinic (S.G: P21/m) phase at 0.74 GPa in addition to several isostructural transitions. Density-functional calculations predict a narrowing of the band gap with pressure, concomitant with the PL energies. The RP-CsPbBr3 NCs exhibit enhanced PL intensity at 1 GPa and show band gap opening at high pressures. This study opens new strategies for tuning not just the structural properties but also tuning planar defects in alkali lead halide crystals for improved optical properties.

*This work was supported by National Science Foundation under Grant No. ECCS-1807263

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Presenters

  • Sorb Yesudhas

    • Department of Physics and Astronomy, University of Missouri - Columbia
    • Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, USA

Authors

  • Sorb Yesudhas

    • Department of Physics and Astronomy, University of Missouri - Columbia
    • Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, USA

  • Maria V Morrell

    • Department of Chemical Engineering, University of Missouri - Columbia, Missouri 65211, USA

  • Matthew J Anderson

    • Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, USA

  • Carsten A. Ullrich

    • Univ of Missouri - Columbia
    • Physics and Astronomy, Univ of Missouri - Columbia
    • Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, USA

  • Curtis Kenney-Benson

    • HPCAT, X-ray Science Division, Advanced Photon Source, Argonne National Lab
    • Argonne National Laboratory
    • Argonne Natl Lab
    • HPCAT, X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont IL, 60439, USA

  • Yangchuan Xing

    • Department of Chemical Engineering, University of Missouri - Columbia, Missouri 65211, USA

  • Suchismita Guha

    • Univ of Missouri - Columbia
    • Physics and Astronomy, University of Missouri-Columbia
    • Department of Physics and Astronomy, University of Missouri, Columbia, MO, USA
    • Department of Physics and Astronomy, University of Missouri - Columbia
    • Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, USA