Size, Shape, Stability, and Color of Plasmonic Silver Nanoparticles

Abstract

The remarkable relationship between the size, shape, and optical properties of silver nanoparticles is proving to be very useful in a range of high performance applications. Considerable effort and investment are focused on delivering silver nanoparticles with precise morphologies. However, the reliability of these particles is contingent upon the morphological stability, particularly against variations in the thermodynamic environment, such as changes in temperature. Using a combination of computational and theoretical approaches, we have constructed a size-and shape-dependent phase diagram of nanoscale silver and projected the optical emission spectrum to produce a detailed structure/property map at thermal equilibrium. This map demonstrates that faceted near-spherical shapes and spheres are the predominant morphologies in a Ag NPs colloidal sample at low and high temperatures, showing a light yellow color. However, samples with more faceted shapes such as cubes or tetrahedrons, which gain stability at sizes smaller than 8 nm at intermediate temperatures, will present brighter yellow hues and dark red colors, respectively.

Kinetic Monte Carlo approach to Schottky defects in noble metal nanoclusters

“…Silver and copper are more recent scientific studies, as copper is difficult to make due to its rapid oxidation. A nano-phase diagram of structure versus temperature has been developed for gold and silver from experiments and density functional theory (DFT) [11,12]. A phase diagram for copper has been produced as an alloy with gold for nanoclusters [13].…”

Experimental and theoretical determination of the plasmonic responses and shape distribution of colloidal metallic nanoparticles

“…17,18 However, preparation routes unavoidably conduct to NPs showing a shape distribution which induces drastic changes in the optical properties of NP assembly. [19][20][21][22] Indeed, by combining Gibbs free energy calculation to discrete dipole approximation, Noguez et al [23][24][25] have shown that the morphology and so the optical properties of NPs depend on the temperature used to synthesize them. In addition, as reported by Sayah et al, 19 silver prolates grown in a mesoporous silica matrix exhibit a large length distribution which induces an inhomogeneous broadening of the L-SPR bands.…”

Correlating charge fluence with nanoparticle formation during in situ plasma synthesis of nanocomposite films

“…Figure (b) and (c) show UV‐vis absorbance spectra of Ag + ‐PAA thin films after exposure to e‐beam generated plasmas at corresponding ranges of pressures and times. Ag nanoparticles are known to exhibit a characteristic absorbance peak in the range of 350–420 nm . The spectra confirm the presence of the localized surface plasmon resonance (LSPR) band associated with Ag nanoparticles.…”