Figure 3.

(a) Cubic and (b) cubic-split model for CsPbCl₃. (c) DSE best fit of RT X-ray synchrotron data (λ = 0.565468 Å) corresponding to the cubic-split model. The 1.8–2.2 Å^–1Q region (inset) matches the cubic phase diffraction features. (d) ADPs behavior of Cl, Cs and Pb ions vs temperature as provided by Rietveld analysis (filled squares) in the 133–298 K range on NCs and by neutron diffraction (empty squares) on single crystal in the 325–623 K range from Sakata et al.⁵⁵ The discontinuity near 320 K is explained by markedly different experimental conditions and methods of analysis. (e) DSE best fit corresponding to orthorhombic coherent subdomains; the 1.8–2.2 Å^–1Q region (inset) well matches the cubic phase diffraction features: (f) schematic representation of a single 1/2[−110](110) twin boundary; (g) atomistic representation of nanotwins within a NC; the twin boundary highlighted in the circle shows the discontinuity of the halides lattice and the coherence of the Pb sublattice; (h) 2D projections of the undistorted orthorhombic structure; and (i) sketch of the cooperative rotations of PbCl₆ octahedra at the twin boundaries as a viable mechanism of the dynamically changing twins network.