Preparation of triangular silver nanoplates by silver seeds capped with citrate-CTA.

Abstract

Due to the competitive growth on the crystal face of seed, it is always difficult to control the morphology of the formation of nanoparticles precisely by a seed-mediated growth method. Herein, we provided a simple but effective technique to synthesize silver nanotriangles using a new silver seed that is capped with citrate-CTA+ (CTA+ is cetyltrimethyl ammonium cation). Compared to the preparation of silver nanoparticles (AgNPs) by a conventional seed-mediated method, in this paper, we presented a growth technique with two distinct innovative changes. First, the concentrations of CTAB that we added in silver seed collosol have a significant impact on the size distribution, and silver nanotriangles, nanorods, and nanospheres could be obtained by adjusting the CTAB concentration. Second, the seed prepared by our method has a longer use time, and silver nanotriangles, nanospheres, and nanorods could be prepared by adjusting the aged time of the seed colloid. We have also shown a simple way to control the morphology of silver nanoparticles in almost the same reactive medium by varying the NaOH concentration. Using the new silver seed capped with citrate-CTA+, we obtained triangular silver nanoparticles with relatively high regularity. Based on the limited experimental results and IR analysis, a possible mechanism was preliminarily proposed to explain the formation of the seed and the truncated triangular AgNPs.