Metallic nanoparticles, in particular precious metal nanoparticles, represent a significant topic of research among nanotechnologists.
Primarily, this is due to the intense optical response that can be displayed by metallic particles of dimensions considerably smaller than of the wavelength of incident light. This response manifests as absorption of specific frequencies of electromagnetic radiation, the mechanism for which is termed “plasmon resonance”. Precious metals are focussed on for their nobility in addition to their plasmon resonance. Plasmon resonance peaks vary depending on elemental composition and particle geometry.
Anisotropic metal particles have been developed, as deviation from solid spherical particle geometry allows for control over the peak absorption properties of the particle.
Recently, syntheses for anisotropic metallic nanoparticles have approached gram scale production levels, which is crucial progress for commercial applications.
One such application is spectrally selective coatings where the absorption band of the coating is controlled by the dimensions of the particles utilised. Gold nanorods or nanoshells can be fabricated to have their peak absorption in the near infrared (NIR) or infrared (IR) to help control heat transfer through windows.
However, metallic nanoparticles that vary from the energetically favourable spherical geometry cannot withstand temperatures necessary for forming glass panels. A possibility for circumventing this issue may be to produce polymer laminates to apply to glass panels once formed.