Alloys of noble metals with augmented quality factors of surface plasmons

Abstract

A set of improved substrates for plasmonic applications characterized by specific characteristics of surface plasmons, such as resonance frequencies, manifesting, notably, as a change of perceived color of said alloys, as well as alteration of surface plasmon energies and generation efficiency compared to the constituent elements. The disclosed compositions include alloys of gold, platinum, and palladium with other chemical elements, especially alkali metals (such as potassium, and rubidium), alkali earth metals (such as magnesium and barium) as well as transition metals (such as tin and zirconium).

We claim: 
     
         1 . A composition of matter such as an alloy with the properties of:
 (i) being comprised of at least one metal selected from gold (Au), platinum (Pt), and palladium (Pd) as the main element of the alloy;   (ii) being comprised of at least one alloying component promoting change in the energy of surface plasmons of the resulting alloy preferably chosen from alkali metals such as potassium (K), and rubidium (Rb), as well as alkali earth metals such as magnesium (Mg), and barium (Ba), as well as transition metals inclusive of tin (Sn), and zirconium (Zr);   (iii) the resulting alloy necessarily and essentially presenting with the property of substantially different energy characteristics of the surface plasmons as present on the surface of objects made from the alloy, including solid items, thin layers and nanoparticles, as compared to any or all of the constituent elements and assessed by one or all of the following manifestations:   a change of surface color as perceived by the human eye as a function of reflectance of specific wavelengths of incident white light;   a change in specific absorbance and reflectance characteristics when illuminated with electromagnetic radiation including ultraviolet, visible, and infrared light as polychromatic mixture of wavelengths, monochromatic illumination or illumination with multiple narrow wavelengths;   a change in efficacy of generation, surface plasmon resonance frequency, specific energies of surface plasmons generated upon illumination of the surface of the alloy with electromagnetic radiation, including ultraviolet, visible and infrared light as polychromatic mixture of photons of multiple wavelengths, monochromatic illumination or illumination with photons of multiple narrow ranges of wavelengths.   
     
     
         2 . A composition of matter comprising:
 an alloy consisting primarily of gold and potassium at atomic ratios of two parts of gold to one part of potassium, with deviation from said ratios not exceeding five atomic percent, which develops, upon preparation of the alloy, the desirable surface color described as reddish-purple as perceived by the human eye, with said color development being of essence.   
     
     
         3 . A composition of matter comprising:
 an alloy consisting primarily of gold and potassium at atomic ratios of five parts of gold to one part of potassium, with deviation from said ratios not exceeding five atomic percent, which develops, upon preparation of the alloy, the desirable surface color described as dark green as perceived by the human eye, with said color development being of essence.   
     
     
         4 . A composition of matter comprising:
 an alloy consisting primarily of gold and rubidium at atomic ratios of five parts of gold to one part of rubidium, with deviation from said ratios not exceeding five atomic percent, which develops, upon preparation of the alloy, the desirable surface color described as dark green-yellow as perceived by eye, with said color development being of essence.   
     
     
         5 . A composition of matter comprising:
 an alloy consisting primarily of gold and rubidium at atomic ratios of two parts of gold to one part of rubidium, with deviation from said ratios not exceeding five atomic percent, which develops, upon preparation of the alloy, the desirable surface color described as dark green as perceived by the human eye, with said color development being of essence.   
     
     
         6 . A composition of matter comprising:
 an alloy consisting primarily of gold and barium at atomic ratios of five parts of gold to one part of barium, with deviation from said ratios not exceeding five atomic percent, which develops, upon preparation of the alloy, the desirable surface color described as gray-blue and shimmering as perceived by the human eye, with said color development being of essence.   
     
     
         7 . A composition of matter comprising:
 an alloy consisting primarily of gold and zirconium at atomic ratios of three parts of gold to one part of zirconium, with deviation from said ratios not exceeding five atomic percent, which develops, upon preparation of the alloy, the desirable surface color described as gray-blue and shimmering as perceived by the human eye, with said color development being of essence.   
     
     
         8 . A composition of matter comprising:
 an alloy consisting primarily of gold, magnesium and tin at atomic ratios of one part of gold to one part of magnesium and one part of tin, with deviation from said ratios not exceeding two atomic percent, which develops, upon preparation of the alloy, the desirable surface color described as reddish-purple as perceived by the human eye, with said color development being of essence.   
     
     
         9 . A composition of matter comprising:
 an alloy consisting primarily of platinum, magnesium and tin at atomic ratios of one part of platinum to one part of magnesium and one part of tin, with deviation from said ratios not exceeding two atomic percent, which develops, upon preparation of the alloy, the desirable surface color described as dark reddish-orange as perceived by the human eye, with said color development being of essence.   
     
     
         10 . A composition of matter comprising:
 an alloy consisting primarily of palladium, magnesium and tin at atomic ratios of one part of palladium with one part of magnesium and one part of tin, with deviation from said ratios not exceeding two atomic percent, which develops, upon preparation of the alloy, the desirable surface color described as brass-like yellow as perceived by the human eye, with said color development being of essence.