Cutting 2D Semiconductors with 'Nano Scissors'

A simplified schematic diagram of the incision process and electron microscope observation results for each incision step.

[Asia Economy Reporter Junho Hwang] A technology has been developed that can cut two-dimensional semiconductors into thin ribbon shapes. Using this technology, the research team cut transition metal chalcogenides, a two-dimensional semiconductor, into ribbon shapes and obtained a material that can replace platinum catalysts used for hydrolysis. Attention is focused on whether a new catalyst that can replace the expensive platinum catalyst needed to split water and obtain hydrogen can be developed.

Cutting Chalcogenides into Ribbon Shapes

Experimental results of hydrogen evolution reaction catalysts using nanoribbons with various morphologies.

Professor Sangwook Kim of the Department of Materials Science and Engineering at the Korea Advanced Institute of Science and Technology (KAIST) and Professor Yoosung Jung of the Department of Bio and Chemical Engineering at the same university announced on the 15th that they have developed a technology to cut transition metal chalcogenide materials, which are two-dimensional semiconductors, into thin ribbon shapes through joint research. The results of this study were published in the international journal Nature Communications on the 6th.

The research team succeeded for the first time in the world in cutting this material into long nanoribbon shapes by simple ultrasonic treatment, cutting it in a specific direction. The team discovered that the surface of the two-dimensional material chemically reacts with oxygen in a specific directionality and cut it into a one-dimensional ribbon shape.

Chalcogenides are compounds of transition metal elements and chalcogen elements. In the planar direction, transition metal elements and chalcogen elements form strong covalent bonds, but in the vertical direction, they have a layered structure with weak van der Waals bonds. When the layers are separated, they can be exfoliated into two-dimensional monolayers.

Possible to Manufacture Multi-element Low-dimensional Nano New Materials

Graph of Gibbs free energy values for hydrogen adsorption on nano ribbon materials.

The one-dimensional ribbon-shaped chalcogenides produced in this way showed hydrogen generation performance comparable to platinum catalysts. This is because cutting into one-dimensional ribbon shapes increased the surface area reacting with oxygen.

A representative of the research team explained, "With the development of a new technology to cut two-dimensional transition metal chalcogenide materials composed of multiple elements, it is expected that various multi-element low-dimensional nano new materials will be manufactured."

Corresponding author Professor Sangwook Kim said, "Although two-dimensional transition metal chalcogenide materials have excellent properties, there has been a lack of methods to precisely control their nanostructures. Through this research, it will be possible to develop new hydrogen generation catalysts that can replace expensive platinum-based catalysts."

Hydrogen is a new energy resource that can replace conventional fossil fuels because it does not emit pollutants. The most environmentally friendly method to produce hydrogen is chemically splitting water, which currently uses expensive platinum catalysts. Research is underway to develop catalysts that can replace these.

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