Rough gold films as broadband plasmonic absorbers of sunlight

Abstract

Plasmonic photocatalysis has two fundamental problems: narrow LSPR absorption band and low absorbance, which limit the utilization efficiency of sunlight. A blackbody-like absorber would be ideal to make full use of the whole solar spectrum. This talk will present new black absorber structures based on Au nanostructures and TiO2 films. The absorber is composed of a TiO2 layer sandwiched between a layer of Au nanoparticles (AuNPs) and a rough Au layer (AuNP/TiO2-Au film). The random nature of Au nanostructures enables the plasmonic absorption of lights at different wavelengths, which generates hot electrons to feed the TiO2 film. Experiments show a strong absorption (72% – 91%) over 400 – 900 nm and a much-enhanced photocurrent (by 20 folds) as compared to the bare TiO2 film, making it ideal for solar applications such as photocatalysis and photosynthesis. This talk will cover the idea, the technical details and the perspectives.