Unusual Selective Monitoring of N,N-Dimethylformamide in a Two-Dimensional Material Field-Effect Transistor

Area of Science:

• Materials Science
• Chemical Sensing
• Nanotechnology

Background:

• N,N-Dimethylformamide (DMF) is a widely used industrial and pharmaceutical solvent.
• Real-time monitoring of DMF is crucial due to its toxicity.
• Selective detection of non-redox-active molecules like DMF in aqueous solutions is challenging.

Purpose of the Study:

• To develop a selective sensor for real-time monitoring of N,N-Dimethylformamide (DMF).
• To investigate the mechanism of selective DMF detection using a novel sensor platform.

Main Methods:

• Fabrication of a molybdenum disulfide (MoS2) field-effect transistor (FET) based sensor.
• Testing the sensor's selectivity against similar molecules (formamide, N,N-diethylformamide, N,N-dimethylacetamide).
• Utilizing a microfluidic chamber for sequential solution exchange and real-time monitoring.

Main Results:

• The MoS2-FET sensor demonstrated high selectivity for DMF, distinguishing it from structurally similar compounds.
• The sensor successfully monitored DMF concentrations in NaCl ionic solutions ranging from 1 to 200 μL/mL.
• Exceptional orientation of DMF molecules at oxygen substitution sites on MoS2 was identified as the sensing mechanism.

Conclusions:

• A novel MoS2-FET based sensor enables selective, real-time detection of the redox-inactive solvent DMF.
• The findings highlight the potential of exploiting non-ideal atomic affinity sites on 2D materials for sensing applications.
• This approach offers a promising strategy for monitoring toxic industrial chemicals in complex solutions.