%A Hanbin Zheng, Christine Picard, Serge Ravaine %T Nanostructured gold films exhibiting almost complete absorption of light at visible wavelengths %0 Journal Article %D 2018 %J Front. Chem. Sci. Eng. %J Frontiers of Chemical Science and Engineering %@ 2095-0179 %R 10.1007/s11705-018-1710-2 %P 247-251 %V 12 %N 2 %U {https://journal.hep.com.cn/fcse/EN/10.1007/s11705-018-1710-2 %8 2018-05-09 %X

Nanostructured metal surfaces have been known to exhibit properties that deviate from that of the bulk material. By simply modifying the texture of a metal surface, various unique optical properties can be observed. In this paper, we present a simple two step electrochemical process combining electrodeposition and anodization to generate black gold surfaces. This process is simple, versatile and up-scalable for the production of large surfaces. The black gold films have remarkable optical behavior as they absorb more than 93% of incident light over the entire visible spectrum and also exhibit no specular reflectance. A careful analysis by scanning electron microscopy reveals that these unique optical properties are due to their randomly rough surface, as they consist in a forest of dendritic microstructures with a nanoscale roughness. This new type of black films can be fabricated to a large variety of substrates, turning them to super absorbers with potential applications in photovoltaic solar cells or highly sensitive detectors and so on.