One-step approach for the synthesis and self-assembly of silver nanoparticles.

This study demonstrates a facile approach for one-step synthesis and self-assembly of silver nanoparticles at ambient conditions. It was found that pyrogallol acid (PYA) can play multiple roles in the proposed synthesis, including a reducing agent, a stabilizer, and a linking agent for assembly. Silver ions can be readily reduced by PYA at room temperature due to its powerful reducing capability. The capability in shape and size control can be evidenced by TEM images. A third function of PYA in this case is to link the generated silver particles into chains through the action of hydrogen bonding, which leads to a new plasmon resonance emerges in the longer wavelength region centered at approximately 650 nm. These results may be useful for shape-controlled synthesis and self-assembly of other metallic nanoparticles. The self-assembly structures would be imposed more functional applications in the areas of optics, plasmonics, biomedicine labeling and ionic sensing.