The absorption and PL features of the PNPls can be directly related to the HAADF-STEM images in Figure . Sample Br-110 is a network of thin (mostly n = 2, ~1.18 nm thick) nanowires (NWs). Sample Br-170 is comprised of nanoplates with well-defined sizes that self-assemble into stacks organized in columns laterally aligned. Similarly, sample I-110 also shows stacks of nanoplates, much smaller than those observed for Br-170, with random orientation. At last, sample I-170 shows a rough size distribution in all dimensions, with nanocrystals varying from nanoplates to nanorods. This behavior can be explained by a size defocusing that widens the size distribution in the case of CsPbI3 perovskite nanocrystals after a few seconds of reaction. Except in the case of sample I-170, we could extract some superlattice parameters of the PNPls using the HAADF-STEM images. A Fast Fourier Transform (FFT) of the images in Figure revealed patterns in the reciprocal space that are proportional to the distance (center-to-center) between the nanoplates and, in the case of Br-170, between the columns of the stacks. These analyses are shown in Figure , and a schematic representation of their structure is shown in Figure . For all the samples, regardless of the composition, the distance between particles is similar, about 5 nm. However, sample Br-110 shows a range of distances from ~4.6 to ~7 nm, reflecting the fluctuation of distances observed in Figure , where the NWs are not perfectly parallel to each other. To estimate the thickness of the PNPls, we evaluated the contrast scale along segments of PNPls for samples Br-110, Br-170, and I-110 (Figure ). The profile peaks (Figure ) were fitted with gaussian functions, and their full width at half maximum (FWHM) were used as the thickness of the PNPls. The parameters of the fits are shown in Table .