Ultra-high sensitivity material - residual graphene

Scientists at the University of Illinois at Chicago have recently developed an ultra-sensitive "electronic nose" that can distinguish individual gas molecules. This new type of gas sensor absorbs gas molecules 300 times stronger than traditional chemical sensors.

It is incredible that the material used to make this high-sensitivity "electronic nose" is a defective graphene that was previously considered defective. The related papers were published on the website of Nature Communications magazine.

In the process of producing graphene, when the graphene gradually forms a lattice or a sheet, some single crystal particles randomly appear. The boundary between this polycrystalline structure and the single crystal is called the grain boundary. Because the grain boundary causes electron scattering and weakens the performance of the graphene lattice, graphene with grain boundaries is generally considered to be worthless. However, the team led by Armin Salisch and Kong Jin, professor of mechanical and industrial engineering at the University of Illinois at Chicago, found that these defects are suitable for manufacturing high-sensitivity gas sensors.

The Physicists Organization reported that in order to test this idea and test the electrical properties of graphene defects, the researchers used a single graphene grain boundary to create a micron-sized gas sensor. They found in the test that the graphene grain boundary can adsorb gas molecules on the surface and allow them to accumulate. This phenomenon is not found on the graphene crystals. This makes graphene with such defects an ideal place for observing gas molecules.

A theoretical chemistry group led by Cech Clarke at the University of Illinois at Chicago explained the unique attractiveness and electronic properties of the grain boundary: the irregular nature of the grain boundary makes it hundreds of different Sensitivity of the electronic transmission gap. It is like many parallel parallel switches. When gas molecules gather on the grain boundary, the switches will suddenly open or close when the charge is transferred. All this happened in a very short time. This is the reason why the gas sensor made of it can have super high sensitivity.

Salish-Nanjin said: "For decades, scientists have been trying to create a powerful, ultra-high sensitivity sensor. Our research has turned it into a reality, and these crystals can be scaled in micron size. The industry integrates and controls the use of this technology to make it easy to fabricate chip-level sensor arrays.Using the grain boundary's superabsorption capacity and rapid reaction capability for gas molecules, electronic noses made with graphene grain boundary arrays are even It is able to detect individual gas molecules. This material is accurate and reliable, making it an ideal material for manufacturing gas sensors."