Fig. 1.

Kinetically controlled AuNP growth using fused microdroplets. a Schematic of the experiment setup. Microdroplets containing 100 µM HAuCl₄ solution were fused with the ones containing 400 µM NaBH₄ solution. The crystallization process was kinetically controlled on the microsecond timescale by adjusting the traveling distance of the fused microdroplets. b TEM images of gold nanoparticles at different time points. Scale bar is 20 nm. c Time-course change in the diameter of the gold nanoparticles. d TEM image of a nanoparticle showing multiple crystalline structures. e Portion of nanoparticles with single or multiple crystalline structures synthesized in microdroplets. Error bars represent one standard deviation of three replicates