Defining Rules for the Shape Evolution of Gold Nanoparticles
Supporting Information for
Defining Rules for the Shape Evolution of Gold Nanoparticles Mark R. Langille,† Michelle L. Personick,† Jian Zhang, Chad A. Mirkin* Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208 E-mail: [email protected] Experiment
Standard Conditions
Variations
10.0 mL 10 mM CTA-Br 125.0 μL10 mM AuCl4 500 μL large seeds
0.05, 0.20, or 1.0 mL 100 mM AA
Reducing Agent
Halides in the Absence of Silver
10.0 mL 50 mM CTA-Cl 0.5 mL 10 mM AuCl4 100.0 μL 100 mM AA 500 μL large seeds
Bromide: 0.0, or 50.0 μL 1M NaBr Iodide: 0.0,10.0, or 75.0 μL 10 mM NaI
10.0, 40.0, or 100.0 μL 10 mM AgNO3
Silver
10.0 mL 100 mM CTA-Cl 200.0 μL 1M HCl 0.5 mL 10 mM AuCl4 100.0 μL 100 mM AA 0.1 μL small seeds 10.0 mL 40 mM CTA-Cl 0.6 mL 1M NaCl 180.0 μL 1M HCl 0.5 mL 10 mM AuCl4 100.0 μL 100 mM AA 0.1 μL small seeds
Bromide: 10.0 μL 10 mM AgNO3 with 0.0, 10.0, 20.0, or 50.0 μL 10 mM NaBr 40.0 μL 10 mM AgNO3 with 0.0, or 40.0 μL 10 mM NaBr Iodide: 10.0 μL 10 mM AgNO3 with 0.0, 1.0, 5.0, or 10.0 μL 0.1 mM NaI
Trace Halides in the Presence of Silver
High Concentrations of Halides in the Presence of Silver
Overgrowth of Concave Cubes in CTA-Br
10.0 mL 100 mM CTA-Cl or Br 200.0 μL 1M HCl 0.5 mL 10 mM AuCl4 100.0 μL 10 mM AgNO3 100.0 μL 100 mM AA 0.1 μL small seeds
150.0 μL 10 mM AuCl4 150.0 μL 10 mM AgNO3 75.0 μL 100 mM AA concave cubes seeds
Chart S1. Summary of Reaction Conditions.
S1
See main text
10.0 mL 100 mM or 20 mM CTA-Br
Figure S1. SEM image of {111}-faceted octahedra produced by slightly lowering the concentration of ascorbic acid in the growth solution to 0.5 mM. This shows that cubes and octahedra are very close in surface energy to one another. Scale bar: 200 nm.
B) Ag Au
3000 Counts (a.u.)
3d3/2
Ag : Au
3500
3d5/2
A)
2500 2000
375
Au Ag C
1500
C) Au
1000
365
4f7/2 4f5/2
Ag : Au
500 0 1000
370
Concentration of Bromide (μM) Binding Energy (eV)
800
600 400 200 Binding Energy (eV)
0 89.5
85.5
81.5
Concentration of Bromide(eV) ( μM) Binding Energy
Figure S2. (A) Representative XPS survey scan and high resolution XPS spectra of (B) Ag 3d and (C) Au 4f peaks used in determining surface silver/gold ratios for nanoparticles formed under various reaction conditions.
S2
Figure S3. XPS data showing the silver coverage on the particles formed with various concentrations of sodium bromide in the growth solution, compared to the published experimental silver coverage in the absence of bromide (black squares). 10 μM silver nitrate (red triangles) with 0.0 μM, 10 μM, 20 μM, 50 μM sodium bromide, and 40 μM silver nitrate (blue circles) with 0 μM, 40 μM sodium bromide.
Figure S4. SEM images of reaction products from growth solutions containing 40 mM CTA-Cl, 40 μM silver nitrate and (A) 0.0 μM and (B) 40 μM sodium bromide. Scale bars: 200 nm. In the S3
absence of bromide, {310}-faceted truncated ditetragonal prisms are formed and with 40 μM bromide, {720}-faceted concave cubes are produced. (C) XPS data showing the silver/gold ratio for particles generated with different concentrations of bromide in the growth solution, showing that as the bromide concentration is increased, the amount of silver on the particles’ surface also increases.
Figure S5. SEM images of reaction products from growth solutions containing 40 mM CTA-Cl, 10 μM silver nitrate and (A) 0.00 μM (B) 0.01 μM (C) 0.05 μM and (D) 0.10 μM sodium iodide. Scale bars: 200 nm. In the absence of iodide, a mixture of {110}-faceted bipyramids and {110}faceted rhombic dodecahedra are produced. With increasing iodide, the size and yield of the bipyramids decrease while the size and yield of the rhombic dodecahedra increase. At 0.10 μM iodide, {310}-faceted truncated ditetragonal prisms are generated. (E) XPS data showing the silver/gold ratio for particles generated with different concentrations of iodide in the growth solution, showing that as the iodide concentration is increased, the amount of silver on the particles’ surface also increases. (F) ICP-AES kinetics data of the reactions containing 0.00 μM (black squares), 0.05 μM (red triangles), and 0.10 μM (blue cicles) of sodium iodide. Final gold concentrations are higher with increasing iodide because the destabilization of the AgUPD layer by iodide allows more gold to be reduced onto the particle surface before the reaction comes to completion.
S4
Figure S6. SEM images of tetrahexahedra produced using growth solutions containing 100 mM CTA-Br and (A) 40 μM silver nitrate and (B) 100 μM silver nitrate. Scale bars: 200 nm.
Figure S7. Schematic of reaction products from solutions containing 100 μM silver nitrate in solutions of (A) 100 mM CTA-Cl, (B) 100 mM CTA-Cl and 100 mM sodium bromide, (C) 100 mM CTA-Br, and (D) 100 mM CTA-Br and 100 mM sodium chloride. Scale bars: 200 nm. At 100 μM silver nitrate, all of the reactions which contain bromide produce tetrahexahedra (B-D) and concave cubes are only produced in the absence of bromide (A). This demonstrates that the effects of bromide dominate over chloride.
S5
Figure S8. SEM images of particles produced in reaction solutions containing 10 μM silver nitrate and (A) 100 mM CTA-Br and (B) 25 mM CTA-Br. Scale bars: 200 nm. With low silver and high CTA-Br, growth is uncontrolled, resulting in stellated particles (A). When the CTA-Br concentration is decreased, more silver is able to deposit on to the particle surface, enabling the stabilization of tetrahexahedra (B).
Figure S9. SEM images of particles produced in reactions containing 500 μM silver and concave cube seeds in (A) 100 mM CTA-Br and (B) 20 mM CTA-Br. Scale bars: 200 nm. At high concentrations of CTA-Br, bromide inhibits silver deposition and overgrown concave cubes are formed (A), while at 20 mM CTA-Br, silver is able to stabilize {111}-facets, leading to the formation of octahedra (B).
S6
Figure S10. SEM image of particles formed in growth solutions containing 10 μM silver, 100 mM CTA-Cl and 10 μM sodium iodide. Scale bar: 200 nm. The presence of iodide leads to poorly controlled growth and particles with extremely stellated features.
Figure S11. TEM images of concave cubes at early stages of growth. (A) 8 minutes, (B) 14 minutes, (C) 20 minutes, and (D) 26 minutes. Scale bars: 50 nm. Even at the beginning of their growth, the particles already possess a concave cubic shape.
S7
Defining Rules for the Shape Evolution of Gold Nanoparticles Mark R. Langille,† Michelle L. Personick,† Jian Zhang, Chad A. Mirkin* Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208 E-mail: [email protected] Experiment
Standard Conditions
Variations
10.0 mL 10 mM CTA-Br 125.0 μL10 mM AuCl4 500 μL large seeds
0.05, 0.20, or 1.0 mL 100 mM AA
Reducing Agent
Halides in the Absence of Silver
10.0 mL 50 mM CTA-Cl 0.5 mL 10 mM AuCl4 100.0 μL 100 mM AA 500 μL large seeds
Bromide: 0.0, or 50.0 μL 1M NaBr Iodide: 0.0,10.0, or 75.0 μL 10 mM NaI
10.0, 40.0, or 100.0 μL 10 mM AgNO3
Silver
10.0 mL 100 mM CTA-Cl 200.0 μL 1M HCl 0.5 mL 10 mM AuCl4 100.0 μL 100 mM AA 0.1 μL small seeds 10.0 mL 40 mM CTA-Cl 0.6 mL 1M NaCl 180.0 μL 1M HCl 0.5 mL 10 mM AuCl4 100.0 μL 100 mM AA 0.1 μL small seeds
Bromide: 10.0 μL 10 mM AgNO3 with 0.0, 10.0, 20.0, or 50.0 μL 10 mM NaBr 40.0 μL 10 mM AgNO3 with 0.0, or 40.0 μL 10 mM NaBr Iodide: 10.0 μL 10 mM AgNO3 with 0.0, 1.0, 5.0, or 10.0 μL 0.1 mM NaI
Trace Halides in the Presence of Silver
High Concentrations of Halides in the Presence of Silver
Overgrowth of Concave Cubes in CTA-Br
10.0 mL 100 mM CTA-Cl or Br 200.0 μL 1M HCl 0.5 mL 10 mM AuCl4 100.0 μL 10 mM AgNO3 100.0 μL 100 mM AA 0.1 μL small seeds
150.0 μL 10 mM AuCl4 150.0 μL 10 mM AgNO3 75.0 μL 100 mM AA concave cubes seeds
Chart S1. Summary of Reaction Conditions.
S1
See main text
10.0 mL 100 mM or 20 mM CTA-Br
Figure S1. SEM image of {111}-faceted octahedra produced by slightly lowering the concentration of ascorbic acid in the growth solution to 0.5 mM. This shows that cubes and octahedra are very close in surface energy to one another. Scale bar: 200 nm.
B) Ag Au
3000 Counts (a.u.)
3d3/2
Ag : Au
3500
3d5/2
A)
2500 2000
375
Au Ag C
1500
C) Au
1000
365
4f7/2 4f5/2
Ag : Au
500 0 1000
370
Concentration of Bromide (μM) Binding Energy (eV)
800
600 400 200 Binding Energy (eV)
0 89.5
85.5
81.5
Concentration of Bromide(eV) ( μM) Binding Energy
Figure S2. (A) Representative XPS survey scan and high resolution XPS spectra of (B) Ag 3d and (C) Au 4f peaks used in determining surface silver/gold ratios for nanoparticles formed under various reaction conditions.
S2
Figure S3. XPS data showing the silver coverage on the particles formed with various concentrations of sodium bromide in the growth solution, compared to the published experimental silver coverage in the absence of bromide (black squares). 10 μM silver nitrate (red triangles) with 0.0 μM, 10 μM, 20 μM, 50 μM sodium bromide, and 40 μM silver nitrate (blue circles) with 0 μM, 40 μM sodium bromide.
Figure S4. SEM images of reaction products from growth solutions containing 40 mM CTA-Cl, 40 μM silver nitrate and (A) 0.0 μM and (B) 40 μM sodium bromide. Scale bars: 200 nm. In the S3
absence of bromide, {310}-faceted truncated ditetragonal prisms are formed and with 40 μM bromide, {720}-faceted concave cubes are produced. (C) XPS data showing the silver/gold ratio for particles generated with different concentrations of bromide in the growth solution, showing that as the bromide concentration is increased, the amount of silver on the particles’ surface also increases.
Figure S5. SEM images of reaction products from growth solutions containing 40 mM CTA-Cl, 10 μM silver nitrate and (A) 0.00 μM (B) 0.01 μM (C) 0.05 μM and (D) 0.10 μM sodium iodide. Scale bars: 200 nm. In the absence of iodide, a mixture of {110}-faceted bipyramids and {110}faceted rhombic dodecahedra are produced. With increasing iodide, the size and yield of the bipyramids decrease while the size and yield of the rhombic dodecahedra increase. At 0.10 μM iodide, {310}-faceted truncated ditetragonal prisms are generated. (E) XPS data showing the silver/gold ratio for particles generated with different concentrations of iodide in the growth solution, showing that as the iodide concentration is increased, the amount of silver on the particles’ surface also increases. (F) ICP-AES kinetics data of the reactions containing 0.00 μM (black squares), 0.05 μM (red triangles), and 0.10 μM (blue cicles) of sodium iodide. Final gold concentrations are higher with increasing iodide because the destabilization of the AgUPD layer by iodide allows more gold to be reduced onto the particle surface before the reaction comes to completion.
S4
Figure S6. SEM images of tetrahexahedra produced using growth solutions containing 100 mM CTA-Br and (A) 40 μM silver nitrate and (B) 100 μM silver nitrate. Scale bars: 200 nm.
Figure S7. Schematic of reaction products from solutions containing 100 μM silver nitrate in solutions of (A) 100 mM CTA-Cl, (B) 100 mM CTA-Cl and 100 mM sodium bromide, (C) 100 mM CTA-Br, and (D) 100 mM CTA-Br and 100 mM sodium chloride. Scale bars: 200 nm. At 100 μM silver nitrate, all of the reactions which contain bromide produce tetrahexahedra (B-D) and concave cubes are only produced in the absence of bromide (A). This demonstrates that the effects of bromide dominate over chloride.
S5
Figure S8. SEM images of particles produced in reaction solutions containing 10 μM silver nitrate and (A) 100 mM CTA-Br and (B) 25 mM CTA-Br. Scale bars: 200 nm. With low silver and high CTA-Br, growth is uncontrolled, resulting in stellated particles (A). When the CTA-Br concentration is decreased, more silver is able to deposit on to the particle surface, enabling the stabilization of tetrahexahedra (B).
Figure S9. SEM images of particles produced in reactions containing 500 μM silver and concave cube seeds in (A) 100 mM CTA-Br and (B) 20 mM CTA-Br. Scale bars: 200 nm. At high concentrations of CTA-Br, bromide inhibits silver deposition and overgrown concave cubes are formed (A), while at 20 mM CTA-Br, silver is able to stabilize {111}-facets, leading to the formation of octahedra (B).
S6
Figure S10. SEM image of particles formed in growth solutions containing 10 μM silver, 100 mM CTA-Cl and 10 μM sodium iodide. Scale bar: 200 nm. The presence of iodide leads to poorly controlled growth and particles with extremely stellated features.
Figure S11. TEM images of concave cubes at early stages of growth. (A) 8 minutes, (B) 14 minutes, (C) 20 minutes, and (D) 26 minutes. Scale bars: 50 nm. Even at the beginning of their growth, the particles already possess a concave cubic shape.
S7
