Figure 2.

ED analysis of a single SP consisting of CsPbBr₃ NCs. (a) ED pattern acquired along the [001] NC zone axis of the SP shown in Figure 1. The appearance of well-defined diffraction spots indicate that the NCs are atomically aligned. The diffraction spots can be indexed clearly up to reflections from the {420} atomic planes. (b) Azimuthal traces at constant scattering vectors q for different atomic reflections, as indicated by the colored semicircles in (a). Fitting the 12 peaks with Gaussian functions (solid lines) gives an average fwhm of 9.6° ± 1.4°, which provides an upper limit of the in-plane rotational freedom of the NCs inside the SP. (c) Two-dimensional schemes of a planar section perpendicular to the [001] superlattice axis, demonstrating the effect of slight rotational disorder. The orange arrows represent the [100] atomic axis of each of the nanocubes.