Selective synthesis of hexagonal Ag nanoplates in a solution-phase chemical reduction process

Two-dimensional (2-D) Ag nanoplates have surface plasmon resonances which can be tuned from the visible to the near-IR by varying the size and morphology of the nanoplates. Due to their anisotropic structures and different surface energy distributions, Ag nanoplates-especially triangular ones-are kinetically stable and can transform into other nanostructures. Taking advantage of the synergetic effects of HNO3 and Cl- in the reduction solution, uniform Ag hexagonal nanoplates (HNPs) have been captured during the transformation of Ag triangular nanoplates (TNPs). The dimensions of the Ag HNPs can be controlled by changing the concentrations of reagents in the reaction or/and reduction solutions. Resonance absorption spectra of the obtained Ag HNPs indicated that their in-plane resonance peaks could be tuned from the visible to the near-IR region, showing their potential applications in medical diagnosis.