Photonically active bowtie nanoassemblies with chirality continuum

In a recent study published in the journal Nature, Dr. Prashant Kumar, in the group of Prof. Kotov at the University of Michigan (USA), reports on bowtie nanostructured microparticles with a chemical structure displaying chirality continuum. Unlike the typical chiral structures, which have a binary left and right chirality, their twist can be precisely controlled from a fully twisted left-handed structure, to a flat pancake, and to a fully twisted right-handed structure. Because of their rapid and straightforward synthesis, the bowtie nano-assembly represents an economical chiral metamaterial showcasing selective reflection of certain types of circularly polarised light. This has important implications in the field of machine vision, as it holds the potential to facilitate accurate navigation of robots in complex human environments. Especially, since dispersions of bowtie particles can be printed on various types of materials.

To explain the gigantic vibrational circular dichroism signals (VCD) of the bowtie nano-assemblies observed experimentally, DFT calculations were done with ADF. Dr. Paul Nicu performed BP86/DZP calculations of large bowtie structures (between 200 and 400 atoms) and the results were analysed using the VCDtools program of AMS’ graphical user interface.

Explore our tutorial on vibrational circular dichroism with ADF.