Extended Data Fig. 8: TEM images of columnar binary superlattices assembled from 5.3-nm CsPbBr₃ cubes and LaF₃ nanodisks.

a, AB(I)-type superlattice of 16.6-nm LaF₃ nanocrystals. b, AB₂(I)-type superlattice of 26.5-nm LaF₃ nanocrystals. c, AB_x-type superlattice of 12.5-nm LaF₃ nanocrystals. d, AB(II)-type superlattice of 9.2-nm LaF₃ nanocrystals. e, AB₂(II)-type superlattice of 12.5-nm LaF₃ nanocrystals. f, AB₆-type superlattice of 21.0-nm LaF₃ nanocrystals. Structural models of the superlattices are presented as insets. Six different columnar structures are observed, as a result of adjusting the cube-to-disk size and number ratios. None of these structures had previously been reported for disk–sphere systems and nor observed by us, highlighting the crucial role of the cubic shape for the formation of these structures (owing to a much higher resulting packing density compared to disk–sphere systems). However, the yield and the lateral extent of the superlattice grains are considerably smaller than those of ABO₃- and NaCl-type superlattices and require further optimization.