X-rays illuminate the particle atomic structure of cyan light emitting 6-monolayers CsPbBr3 nanoplatelets by Total Scattering

X-rays illuminate the highly debated mesoscale atomic structure of light-emitting perovskite nanoplatelets by high-quality XRPD. Highly anisotropic colloidal CsPbBr₃ nano-platelets (NPLs) as colloidal quantum wells show enhanced light emissivity. Electron microscopy provides a clue on the NPLs pseudocubic faceting. Total Scattering techniques, within the Debye scattering equation (DSE) approach, look in depth at the NPL atomic structure. The NPLs are six-monolayers thick with an orthorhombic Pnma structure. The axial and equatorial bromides of the PbBr₆ octahedra orientations are strongy correlated to the morphological axes. The NPL facets correspond to the {010} (side facets) and the {101} (basal facets) orthorhombic lattice planes, respectively. A lattice relaxation in comparison to cuboidal CsPbBr₃ is detected, with the major deformation in the axial direction. The analysis also supports a CsBr surface termination, with half Cs sites and a half (or slightly more) Br sites vacant.