Indians produce boron nanosheets as thin as graphene

Print edition : March 02, 2018

The flower-like morphology of a self-assembled boron-rich nanostructure as observed under an electron microscope while developing a recipe to synthesise nanoforms of boron. The size of the bud is ~1 micron.

RESEARCHERS at Indian Instituteof Technology Gandhinagar have produced one of thinnest materials ever known to humankind.

Kabeer Jasuja, an assistant professor of Chemical Engineering, along with two of his research students, almost serendipitously synthesised nanosheets—which are 100,000 times thinner than a sheet of paper—made up of boron. “The rich chemistry of boron is expected to make these nanosheets useful for not only storing energy but also for generating energy in a green way,” said Jasuja, whose team published the findings in the journal ChemPhysChem recently. “We are now working towards utilising these nanosheets for developing the next generation batteries and nanocatalysts,” he said.

The IIT Gandhinagar researchers hit upon this novel material quite accidentally when they were trying to develop a recipe for synthesising boron-rich nanomaterials.

They observed that there are some boride compounds, commonly used as ceramics, that dissolve in water just like sugar. But when the solution was left by itself for a few hours, quite surprisingly, the crystals began to grow again. What makes their discovery interesting is that during this recrystallisation, the small clusters were not growing in a three-dimensional way; rather, these were growing in the form of extremely thin sheets. What makes these nanosheets special is that the boron atoms in these nanosheets were found to be arranged symmetrically in the form of a honeycomb. This makes these nanosheets similar to graphene, a honeycomb of carbon atoms which is the world’s thinnest material, and the discovery of which led to the 2010 Nobel Prize in Physics.

Researchers across the world have been trying to make such boron cousins of graphene. The technique developed by the research team at IIT Gandhinagar is not only inexpensive and simple in design, but also results in an aqueous colloid of these nanosheets, which means that a drop of water from this colloid would contain thousands of nanosheets swimming like micro-carpets.

At such a small thickness, matter starts behaving in unusual ways and results in properties which are at the extremes of all known materials. For example, although graphene is only one atom thick, it is approximately 200 times stronger than steel.

T.V. Jayan