(a) HAADF-STEM image of a typical Au-Fe3O4 nanocrystal; (b) The overlaid fast FFT patterns of Au and Fe3O4 lobes; (c-e) EDS elemental mapping of a single Au-Fe3O4 nanocrystal.
Au-Fe3O4 dumbbell nanocrystals with different lobe size ratios in (a-d) organic solvent and (e-h) aqueous solutions correspondingly (all scale bars are 50 nm).
Clusters consisting of 2, 3 and 4 dumbbell nanocrystals
(a) Scheme of ligand exchange for polystyrene polymers onto the Au lobe; (b-c) TEM analyses of assembly structures of Janus dumbbell nanocrystals coated with polystyrene: (b) bright-field TEM image, (c) HAADF-STEM image, and EDS elemental mapping for (d) Au, (e) Fe and (f) Fe+Au.
(a) Janus dumbbell nanocrystals dried from solution of pH=8; (b) Janus dumbbell nanocrystals dried from solution of pH=4; (c) UV-Vis spectra of Janus dumbbell nanocrystals cycled between pH=4 and 8; (d) the adsorption intensity at 538 and 529 nm when Janus dumbbell nanocrystals cycled between pH=4 and 8.
(a) TEM image of Janus Au-Au-Fe3O4 nanocrystals obtained by growing Au nanocrystal domains on Au-Fe3O4 dumbbell nanocrystals; (b) Self-assembly of Janus Au-Au-Fe3O4 nanocrystals shows large domains of Au lobes interconnecting with each other; (c) Comparison of UV-Vis spectra of structures assembled from different Janus nanocrystals. The bigger structures assembled with larger hydrophobic moiety lead to stronger LSPR effect.
