If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.



Chemistry In Pictures

Chemistry in Pictures: Dandelions and darkness

by Manny Morone
December 31, 2019

An SEM image of a group of nanostructures that look like fuzzy dandelions near the edge of a material's surface.
Credit: Viney Ghai
A piece of a material with nanostructures on the its surface that makes the material appear nearly perfectly black.
Credit: Viney Ghai

These micro-size dandelion-like structures are small, but they have a big effect when they cover a material’s surface. So-called flower carbon nanotubes (FCNTs) developed by Prabhat K. Agnihotri’s team at the Indian Institute of Technology Ropar can absorb more than 99.9% of the light that falls on them, producing vanishingly black materials (bottom). The researchers make the FCNTs at roughly 800 °C by first growing the “stems” from acetylene gas, which forms carbon nanotubes on contact with small islands of an iron catalyst on a silicon surface. As the tip of the stems grow, the catalyst becomes less active till growth stops. By flowing hydrogen over those stems, Agnihotri’s team reactivates the iron catalyst and breaks it into smaller pieces, which are treated with acetylene gas again to make the smaller “petal” structures.

Credit: Viney Ghai, Read the paper at ACS Appl. Nano Mater. 2019, DOI: 10.1021/acsanm.9b01950

Do science. Take pictures. Win money. Enter our photo contest here.

Related C&EN Content:

Artist explores the blackest black

Chemistry in Pictures: Carpet of nanoflowers

Chemistry in Pictures: Nano succulent.


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.