Black gold: Broadband, high absorption of visible lightfor photochemical systems

Charlene Ng, Lim Wei Yap, Ann Roberts, Wenlong Cheng, Daniel E. Gomez

Research output: Contribution to journalArticleResearchpeer-review

71 Citations (Scopus)


Here, a black Au surface is presented: a material solely composed of Au that is capable of absorbing more than 92% of the incident light over a spectral region ranging from 300 to 600 nm and that can maintain a high absorbance (above 70%) for wavelengths up to 800 nm. The black Au surface is fabricated by a simple and scalable template-assisted physical vapor deposition technique and possesses the flexibility of adhering to any arbitrary substrate. The high absorbance of Au originates from the close packing of high aspect ratio Au nanotubes possessing a random tapered wall thickness. Fabry–Perot resonances of gap-plasmon modes between the Au nanotubes are also responsible for the strong suppression of reflectance of black Au as demonstrated by finite element method simulations. Furthermore, the ability of this surface to drive photochemical transformations under visible light illumination is demonstrated. Hence, black Au could provide a new paradigm for the use of highly absorbing metal nanostructures to effectively harvest the entire visible spectrum for photorelated applications such as solar fuel production,photodetection, and photovoltaics.
Original languageEnglish
Article number1604080
Pages (from-to)1-9
Number of pages9
JournalAdvanced Functional Materials
Issue number2
Publication statusPublished - 2017


  • black metals
  • broadband absorbers
  • metal nanotubes
  • photocatalysis
  • photochemical transformations

Cite this