Fig. 5From: A Facile pH Controlled Citrate-Based Reduction Method for Gold Nanoparticle Synthesis at Room TemperatureTEM images of AuNPs formed with various citrate to AuCl3 ratio (a) 1:1, (b) 2:1, (c) 3:1, and (d) 5:1. The pH value was fixed at 5 for all cases. Agglomeration of particles takes place for molar ratios other than 2:1 and 5:1 (for TEM images with particle distribution on a larger scale, see Additional file 1: Figure S1)Back to article page