Chemically Triggered Metamorphosis of Colloidal Bilayer Sheets into Nanomazes and Their Conversion into Silicon and Plasmonic Optical Nanomazes

Development of a convenient method for complex nanostructures on substrates is essential in fabricating economically viable functional nanosurfaces for electronics, bioengineering, optoelectronics, and energy systems. Colloids can be introduced to make complex patterns, but substrate modification/modulation, more than two types of colloids, and specially designed colloids are required. Herein, it is discovered that colloidal nanomazes are created from a metamorphosis of colloidal bilayer sheets when the sheets are immersed in a salt aqueous solution. Closely and regularly packed colloids in the bilayer spontaneously rearrange their arrays (separation, settling, and insertion) in the solution: This mechanism, suggested from the experimental results, enables the straightforward production of nanostructures without experiencing complex procedures. Additionally, it is demonstrated that the colloidal nanomazes are successfully transformed into functional inorganic nanomazes, Si and Au nanomazes. The anti-reflective functions of colloidal and Si nanomazes lower the light reflectance or increase the light transmittance: The transmittance of a transparent substrate can be further increased by fabricating the colloidal nanomazes on its both sides. Au nanomazes can also lower the light reflectance, which are discussed with theoretical calculations. The calculation further suggests the Au nanomazes can extensively manipulate the visible-near infrared light, irrespective of polarization modes, from fine tuning the nanomaze geometries.

Automated summary

In this study, it was found that colloidal bilayer sheets can be transformed into colloidal nanomazes by immersing them in a salt aqueous solution. This discovery enables the straightforward production of nanostructures without complex procedures. The colloidal nanomazes can be further transformed into functional inorganic nanomazes with anti-reflective functions.