Chemically synthesized gold and silver particles absorbing in the near-IR spectral range

We propose methods for creating spherical gold particles of submicron size and silver rod-like particles with transverse dimensions of $\sim$ 10 nm and an aspect ratio of 1: 10. Factors determining the frequency of plasmon resonances are considered, reagents are selected, and their ratios for obtaining prolate silver particles are determined. An optimal concentration of the surfactant is determined for creating most elongated silver particles. A shift of the plasmon absorption toward the near-IR range of the spectrum is obtained.