Research ArticleMATERIALS SCIENCE

Hollow metal halide perovskite nanocrystals with efficient blue emissions

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Science Advances  24 Apr 2020:
Vol. 6, no. 17, eaaz5961
DOI: 10.1126/sciadv.aaz5961
  • Fig. 1 Processing and photophysical properties of CsPbBr3 thin films containing 3 mol % NaBr and varying concentrations of EDABr2.

    (A) A schematic showing the one-step spin coating followed by low-temperature thermal annealing. (B) Thin films with various concentrations of EDABr2 under ambient light (top) and ultraviolet (UV) irradiation (bottom). (Photo credit: M.W., Materials Science and Engineering Program, Florida State University.) (C) Photoluminescence (PL) and absorption spectra, (D) time-resolved PL (TRPL) decay curves, and (E) PLQE and emission peak wavelength of thin films with EDABr2 molar ratio varying from 0 to 1.2 with respect to the perovskite precursors. a.u., arbitrary units.

  • Fig. 2 Structural and surface characterization of thin films.

    (A) SAED patterns of thin films. (B) XRD patterns of thin films. (C) Pseudo-Voight peak fitting of the diffraction peaks for the (121) and (D) (202) crystallographic planes of thin films. Photoelectron spectra from x-ray photoelectron spectroscopy (XPS) and Gaussian peak fitting for (E) Br 3d and (F) Pb 4f core levels.

  • Fig. 3 TEM characterization of thin films.

    Transmission electron microscopy (TEM) images of (A) CsPbBr3-Na, (B) EDA5, and (C) EDA5-Na thin films. Insets: particle and pore size distribution of NCs. High-resolution TEM (HRTEM) images of (D) CsPbBr3-Na, (E) EDA5, and (F) EDA5-Na thin films. Inset: Simulated HRTEM images showing lattice fringes for the (101) planes.

  • Fig. 4 Proposed formation mechanism and crystal structures.

    (A) Proposed formation mechanism of hollow CsPbBr3 NCs beginning from Na+ and Br diffusion from the surface to the core and vice versa, respectively, followed by Pb2+ diffusion via Pb2+ vacancies culminating in vacancy condensation (B) changes of the crystal structures of CsPbBr3 upon the additions of NaBr, EDABr2, and both NaBr and EDABr2.

  • Table 1 Composition and photophysical properties of representative thin-film samples.

    λem is the wavelength at the emission maxima, ϕ is the PLQE, and τavg is the average PL lifetime. FWHM, full width at half maximum.

    SampleComposition
    (CsPbBr3:EDABr2:NaBr)
    λem (nm)FWHM (nm)ϕ (%)τavg (ns)
    CsPbBr31:0:0525230.514
    CsPbBr3-Na1:0:0.03525230.518
    EDA51:1:04982281.5200
    EDA5-Na1:1:0.034782472150

Supplementary Materials

  • Supplementary Materials

    Hollow metal halide perovskite nanocrystals with efficient blue emissions

    Michael Worku, Yu Tian, Chenkun Zhou, Haoran Lin, Maya Chaaban, Liang-jin Xu, Qingquan He, Drake Beery, Yan Zhou, Xinsong Lin, Yi-feng Su, Yan Xin, Biwu Ma

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    • Figs. S1 to S16
    • Tables S1 to S4

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