Figure 5.

This figure shows the early-time evolution of GNP growth measured by UV-vis, static light scattering, and AFM using 50 pM citrated ~ 23 nm seeds in aqueous precursor solutions containing L31(8 mM)/F68(4 mM) and ≈ 1 mM Au(III). (A) Absorbance (535 nm) and (B) scattering intensities (450 nm) for 0 (open circles) and 50 pM (closed circles) citrated seeded precursor solutions. The absorbance curves in (A) are fitted with an aggregative model: $Abs\left(t\right)=A-B\cdot e^{-k{t}^n}+\frac{C(t-t_{OR})}{\left(1+e^{-w(t-t_{OR})}\right)}$. For unseeded conditions the fits are: n = 1, k = (3.11 ± 0.60) × 10⁻¹ min⁻¹, t_OR = (10.4 ± 0.8) min, A = (4.6 ± 0.2) × 10⁻³, B = (3.0 ± 0.2) × 10⁻³, C = (2.9 ± 0.8) × 10⁻⁴ min⁻¹, w = 1 min⁻¹. For seeded conditions (50 pM seeds) the fits are: n = 1, k = (2.10 ± 0.09) × 10⁻¹ min⁻¹, t_OR = (11.5 ± 1.5) min, w = 1 min⁻¹, A = (1.04 ± 0.02) × 10⁻¹, B = (7.74 ± 0.12) × 10⁻², C = (9.7 ± 6.5) × 10⁻⁴ min⁻¹. For light scattering in (B), the curves are fitted with a combined RLCA and DLCA model: I(t) = y₀ + y₁e^{−y₂t−2.1} + y₃t , where y₀ is constrained to unity. For unseeded conditions the fits are: y₁ = 1.17 ± 0.06, y₂ = 45 ± 0.2 min^2.1, y₃ = (4.3 ± 0.3) × 10⁻² min⁻¹. For seeded conditions (50 pM seeds) the fits are: y₁ = 3.56 ± 0.57, y₂ = 34 ± 1 min^2.1, y₃ = (3.8 ± 0.3) × 10⁻² min⁻¹. Representative AFM images (C) (512 × 512 pixels − 5 × 5 μ>m²) and (D) (1024 × 1024 pixels − 10 × 10 μ>m²) with height distributions (E) at 2 (dashed line; N = 265) and 12 (solid line; N = 912) minutes, respectively.