This illustration shows nanoclusters of magnesium oxide sandwiched between layers of graphene. Image: Lei Tao/Rice University.Researchers at Rice University have modeled a nanoscale sandwich, the first in what they hope will become a molecular deli for materials scientists. Their recipe puts two slices of atom-thick graphene around nanoclusters of magnesium oxide, thereby providing the super-strong, conductive, carbon-based material with enhanced optoelectronic properties.
Rice materials scientist Rouzbeh Shahsavari and his colleagues built computer simulations of the compound and found it would possess properties suitable for sensitive molecular sensing, catalysis and bio-imaging. This work, which is reported in a paper in Nanoscale, could help researchers design a range of customizable hybrids of two- and three-dimensional structures with encapsulated molecules, Shahsavari said.
The scientists were inspired by earlier experiments, in which various molecules were encapsulated using van der Waals forces to draw components together. The Rice-led study was the first to take a theoretical approach to defining the electronic and optical properties of one of these nanoscale sandwiches – two-dimensional magnesium oxide in bilayer graphene.
"We knew if there was an experiment already performed, we would have a great reference point that would make it easier to verify our computations, thus allowing more reliable expansion of our computational results to identify performance trends beyond the reach of experiments," Shahsavari said.
Graphene on its own has no band gap – the characteristic that makes a material a semiconductor. But the hybrid does, and this band gap should be tunable, depending on the components; the enhanced optical properties should also be tunable and useful.
"We saw that while this single flake of magnesium oxide absorbed one kind of light emission, when it was trapped between two layers of graphene, it absorbed a wide spectrum. That could be an important mechanism for sensors," Shahsavari explained.
He added that his group's theory should be applicable to other two-dimensional materials, like hexagonal boron-nitride, and molecular fillings. "There is no single material that can solve all the technical problems of the world," Shahsavari said. "It always comes down to making hybrid materials to synergize the best features of multiple components to do a specific job. My group is working on these hybrid materials by tweaking their components and structures to meet new challenges."
This story is adapted from material from Rice University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.