1-amino-9-octadecene, HAuCl 4, hexane, ethanol 55 o C, 16h AuSSs on GO

Transcription

1 Supplementary Figures GO Supplementary Figure S1 1-amino-9-octadecene, HAuCl 4, hexane, ethanol 55 o C, 16h AuSSs on GO Schematic illustration of synthesis of Au square sheets on graphene oxide sheets. AuSSs are synthesized by heating a solution containing 1-amino-9-octadecene, HAuCl 4, hexane and ethanol at 55 o C for 16 h. 1

2 a b Supplementary Figure S2 EDX analysis of Au square sheet. EDX spectra of (a) an AuSS deposited on a copper grid, and (b) empty area on the copper grid. 2

3 Supplementary Figure S3 Estimation of the thickness of an Au square sheet by measuring the widths of the folded edges. a, TEM image of a folded AuSS, with measured average width of the folded edges of ~ 2.4 nm. b, Schematic illustration shows how the AuSS folded in (a). c, Schematic illustration of section analysis of line S-S in (b) shows the thickness of AuSS can be estimated from the width of the folded edge. 3

4 Supplementary Figure S4 AFM measurement of a typical Au square sheet grown on graphene oxide. The section analysis reveals that the thickness of the AuSS is ~ 4 nm. 4

5 Supplementary Figure S5 N1s XPS spectrum of the synthesized Au square sheets on graphene oxide. The peak at ev can be assigned to the un-ionized amine groups bound to AuSS surface 39. The ones at and ev can be assigned to imide and amide groups, respectively 40,41, probably resulting from the reactions between the functional groups of GO and the amines. 5

6 a b hcp [110] hcp [320] Supplementary Figure S6 Calculated electron diffraction patterns of hcp-au. SAED patterns of the (a) [110] and (b) [320] zone axes of 2H-hcp-Au. 6

7 a b c Supplementary Figure S7 XRD analysis of synthesized Au nanostructures. a, XRD pattern of AuSSs grown on GO. Inset: Gaussian fitting of the peaks at ~38 o. b, XRD pattern of AuSSs without preferred orientation. A very concentrated solution was dropped on substrate and the AuSSs did not show the preferred orientation, so that different planes could contribute to the diffraction. c, XRD pattern of thick Au plates deposited on substrate. 7

8 Supplementary Figure S8 Calculated [110] HRTEM images of 2H-hcp-Au. The input atomic parameters were obtained from the XRD data, i.e. a = 2.96 Å and c = 4.84 Å. 8

9 Supplementary Figure S9 TEM analysis of thick Au square-like structures. a, TEM image of a thick Au squarelike structure grown from the AuSS. b, TEM image showing the edge of a folded thick Au square-like structure. The thickness of this structure is estimated to be 6.0 ± 0.7 nm. c, HRTEM image of the designated area in (b). Examples of hcp and fcc domains are marked. Inset: the corresponding FFT diffraction pattern. 9

10 Supplementary Figure S10 TEM image of synthesized structures without using graphene oxide sheets as templates. A mixture of AuSSs, Au nanowires, and Au nanoparticles were obtained. The AuSSs have a size distribution of nm in edge length.. 10

11 Supplementary Figure S11 TEM image of products obtained after 8-hour reaction. (1-amino-9-octadecene)AuCl polymers in the shape of squares were observed on GO surface. 11

12 a b c hcp d e f Stacking fault Stacking fault Stacking fault fcc Twins fcc Twins fcc Supplementary Figure S12 A series of HRTEM images of an Au square sheet under e-beam irradiation. Images taken at (a) 0, (b) 20, (c) 40, (d) 60, (e) 150, and (f) 270 s. In (b) and (c), the fcc packing domains are marked in red rectangles. Defected area in (d) is marked in dotted red rectangle. 12

13 a b 4 nm Darkness (a.u.) Edge Sheet Edge Particle 100 nm 100 nm Supplementary Figure S13 Thickness estimation of the square center of a dendritic structure based on the contrast of a TEM image. a, TEM image of an Au nanostructure with dendritic edges and square sheet center, and an Au nanoparticle with a size of ~ 4 nm. b, Darkness profile of a line crossing the Au nanoparticle, the dendritic edge and the square sheet in (a). The particle is darker than the square sheet center and brighter than the dendrites at the edges, which means that the square sheet is thinner than 4 nm and the dendrites are thicker than 4 nm. Supplementary references: 39. Raghuveer, M. S. et al. Site-selective functionalization of carbon nanotubes. Adv. Mater. 18, (2006). 40. Jansen, R. J. J. & Bekkum, H. XPS of nitrogen-containing functional groups on activated carbon. Carbon, 33, (1995). 41. Cecchet, F. et al. Grafting of benzylic amide macrocycles onto acid-terminated selfassembled monolayers studied by XPS, RAIRS, and contact angle measurements. J. Phys. Chem. B 107, (2003). 13