Alchemic visible plasmonic properties of colloidal PtIn2 intermetallic nanoparticles (Invited Paper)

Nanoparticles (NPs) of coinage metals such as Au, Ag, and Cu, have been predominantly researched for their intrinsic exhibition of localized surface plasmon resonance (LSPR) in the visible region. Alloy NPs containing these coinage metals have been used to control the LSPR wavelength, but most of them have face-centered cubic (fcc)-based crystal structures. Recently, we have achieved LSPR in the visible region with intermetallic compound NPs that do not contain coinage metals. The colloidal PtIn2 NPs with a C1 (CaF2-type) crystal structure can be synthesized by the liquid phase method. These NPs show LSPR at wavelengths akin to fcc-Au NPs. These findings dramatically expand the plasmonic nanomaterials library and will contribute to our understanding of the LSPR properties of intermetallic NPs.