Ultrathin Nanosensors Provide Clear Optical Fingerprints for Detecting Contaminant Molecules
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[China Instrument Network Instrument Development] Sensors made of ultra-thin nano materials detect contaminant molecules by providing clear optical fingerprints to improve the accuracy of environmental remote sensing. Traditional sensors rely on small peak shifts and intensity changes to detect contaminant molecules in the air, but this method is not accurate.
The contaminant molecules are identified by activating dark electron states in the sensor material and creating new visible peaks. Changes in the optical fingerprint of the sensor material demonstrate the presence of contaminant molecules.
A team of researchers from Chalmers University of Technology in Sweden and Berlin University of Technology in Germany developed a highly efficient sensor using atomic-thickness transition metal disulfides (TMDs). TMDs have an excellent surface area to volume ratio and a strong light-to-substance interaction, making the material very sensitive to changes in the surrounding environment.
In addition to displaying bright excitons, TMDs can also display various dark excitons whose angular momentum or centroid momentum is not zero. The new sensor recognizes molecules by activating excitons in nanomaterials. The contaminant molecules on the surface of the nanomaterial interact with dark excitons and make it visible (lightening), and change the optical fingerprint to show the presence of contaminant molecules.
The team demonstrated that the exciton and bright exciton in the TMDs are coupled with high efficiency, while the non-covalent linking molecules with strong dipole moments may cause the exciton to emit light, resulting in additional peaks in the spectrum.
"This method may open up new possibilities for the detection of environmental gases," said researcher Maja Feierabend. "Our approach is more stable than conventional sensors because the new sensors rely on small changes in their optical properties." When illuminated on the sensor, an optical fingerprint of the material will be displayed.
"Our approach has great potential in ultra-thin, high-speed, high-efficiency, and precise sensor research. In the future, with this method, it is hoped that a highly sensitive and highly discriminating sensor for environmental research will be produced." Researcher Ermin Malic Say.
The team submitted a patent application for its new sensor. Next they will cooperate with experimental physicists and chemists to prove the principle of this new chemical sensor.
The study has been published in Nature Communications.
(Title: Nanoscale Sensors Provide Clear Optical Fingerprints for Pollutant Identification)