Figure 5.

Typical TEM images and the corresponding size distributions of colloidal Au nanoparticles synthesized by varying the initial concentration of the aqueous HAuCl4 solutions: a 1.0 mM, Av = 5.88 nm, SD = 1.27 nm; b 1.5 mM, Av = 7.95 nm, SD = 1.60 nm; c 2.0 mM, Av = 9.84 nm, SD = 1.67 nm.Scale bar: 50 nm. Av is the average particle size, and SD denotes the standard deviation of the size distribution

Liang et al. Nanoscale Research Letters 2009 5:124-129   doi:10.1007/s11671-009-9453-0