Fig. 3: Experimental synthesis of patchy NPs following facet and concentration-dependent stencilling.

a,b, Schematics illustrating low-index facets on gold (a) and the correspondingly coloured facets of the five core NP shapes (b). c–e, Representative TEM image (inset, TEM image with false-coloured patches in cyan) (c), histogram of the number of patches on each NP, n (inset, schematic showing iodide (purple) and 2-NAT (orange) covered regions) (d) and 3D reconstruction of TEM tomography of the patchy NP and its representative cross-sectional views (e). ‘Other’ in the histogram (d) refers to other patch patterns, including fully coated ones. f–n, Similar characterizations for patchy bipyramids (f–h), face-patched cuboctahedra (i–k) and vertex-patched cuboctahedra (l–n). o,p, SEM images of web-like patched cubes (o) and face-patched cubes (p). Top inset, SEM image with false-coloured patches in cyan. Bottom inset, schematic showing iodide (purple) and 2-NAT (orange) dominant regions. q,r, SEM images of hybrid patched rhombic dodecahedra (q) and face-patched rhombic dodecahedra (r). Small vertex patches are located on the {100} truncated vertices of hybrid patched rhombic dodecahedra (q), some of which are indicated with white arrows. Note that, in the SEM images (o–r), the dark regions on the NPs are the polymer patches, as also highlighted in cyan in the insets. More than 100 NPs (208 NPs (d), 102 NPs (g), 141 NPs (j) and 130 NPs (m)) are analysed to determine the synthesis yield of each patchy NP type. Scale bars, 200 nm (20 nm for inset images).