Aluminum May Replace More Expensive Metals for Plasmonics
So often it seems in science that technologies start with the most expensive materials and tools, making it nearly impossible to take out of the lab. Of course there are reasons why expensive materials, such as gold and silver are used, but it is always welcome research to find another, cheaper material that can do the job just as well, or even better. Such appears to be the case with plasmonics and aluminum, according to some Rice University researchers.
Plasmons are a kind of quasiparticle, formed by the coupling of a photon and electron. This combination can allow the energy of a photon to flow over a metal as though it were an electrical current, which can be exploited for some interesting optical devices. Gold and silver nanoparticles are often uses in plasmonics, in part because they do not oxidize. Aluminum does naturally oxidize, which has prevented it from being adopted as the materials response to different light frequencies has seemed to change in prior studies. This new research indicates however, that that the optical response of aluminum nanoparticles is partially related to the amount of oxidation. As aluminum oxidizes only to a point, this means that the changes to a nanoparticle's optical properties eventually stabilize, in a predictable way.
The researchers also discovered that plasmons on aluminum nanoparticles will obey quantum mechanics across a larger range than silver or gold nanoparticles. This could have a great impact on the future of plasmonics, in more ways than just reducing costs.
Source: Rice University