plasmon responses in the sodium tungsten bronzes

The sodium tungsten bronzes (na x wo3) are vividly coloured metallic materials where the optical behaviour can be attributed to the bulk plasma frequency occurring in the visible part of the spectrum. a combination of density functional theory (dft) calculations and experimental electron energy-loss spectroscopy (eels) was used to assess their bulk and surface plasmon responses. it was observed that na x wo3 can sustain strong localised surface plasmon resonances (lspr) with an energy that can be tuned by changing the na content. they have a stronger plasmonic response when compared to au and do not suffer from the atmospheric corrosion of ag, giving them good potential for plasmonic applications.