Al-In nanoparticles and their clusters as solar spectrum plasmonic resonators

Noble metal nanoparticles are the most widely used systems of plasmonic scatterers. They have been used for applications involving light harvesting, optical filters etc. However, scalability of technologies is impacted; this has to do with their prohibitive costs. Use of earth-abundant elements is thereby worth exploring. Al NPs, standalone is a reasonable solar spectrum scatterer, over a broad wavelength range (400–800 nm). But Al plasmonic response is sensitive to surface oxidation and corrosion, which compromises its performance when deployed in a device. Here we show that Al-In alloys are plausible choices. Al-In nanoalloys of diameter 85 nm show a scattering cross section of nearly 8 × 10−14 m2. Al-In nanoparticles scattering cross-sections are invariant with In concentration. Furthermore, all features of Al plasmon resonance are retained making it relevant for solar applications. Al-In heptamers of diameter 150 nm show resonance and anti-resonance peaks at 510 nm and 590 nm wavelengths respectively; making it relevant for prospective filter applications.