Ultrasensitive chemical sensor using N-doped graphene

A model showing the charge transfer (e-) mechanism of Rhodamine B molecules (top) interacting with N-doped graphene (bottom sheet) when excited with different laser lines, which leads to ultrasensitive molecular sensor with N doped graphene. The white, blue and red balls represent carbon, nitrogen and oxygen atom respectively. Credit: Terrones Lab / Penn State.

Researchers from Penn State developed an ultrasensitive Raman spectroscopy-based chemical sensor using nitrogen-doped graphene as substrate.

Raman spectroscopy has been a widely used technique in many industries to detect the unique internal vibrations of molecules. When a laser light irradiates crystals or molecules, it scatters and shifts colors. The scattered laser light can be detected and the Raman spectrum is almost a fingerprint for Raman system. So fingerprint detection could be expected using this technique.

“By controlling nitrogen doping we can shift the energy gap of the graphene, and the shift creates a resonance effect that significantly enhances the molecule’s vibrational Raman modes,” said lead author Simin Feng, a graduate student in Terrones’ group.

“We carried out extensive theoretical and experimental work. We came up with an explanation of why nitrogen-doped graphene works much better than regular graphene. I think it’s a breakthrough, because in our paper we explain the mechanism of detecting certain molecules,” added Terrones, professor of physics, chemistry and materials science at Penn State.

The technique developed using this system could detect molecules in a solution at very low concentrations.

More information can be found at:
http://news.psu.edu/story/418359/2016/07/22/research/ultrasensitive-sensor-using-n-doped-graphene




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