Solution-gated graphene field effect transistors integrated in microfluidic systems and used for flow velocity...

Area of Science:

• Materials Science
• Microfluidics
• Sensor Technology

Background:

• Solution-gated graphene field-effect transistors (SGGT) offer unique electronic properties for sensing applications.
• Microfluidic systems enable precise control and manipulation of small fluid volumes.
• Graphene-based sensors are being explored for diverse applications due to their high surface area and conductivity.

Purpose of the Study:

• To investigate the ion-sensitive properties of SGGTs with Ag/AgCl gate electrodes in microfluidic systems.
• To develop SGGTs as flow velocity sensors within microfluidic channels.
• To explore the potential of SGGTs for sensing ionic strength and zeta potential.

Main Methods:

• Integration of SGGTs into microfluidic devices.
• Characterization of SGGT transfer curves under varying ionic concentrations (KCl).
• Measurement of streaming potentials generated by fluid flow in microchannels.

Main Results:

• SGGT transfer characteristics exhibited a horizontal shift correlated with ionic concentration, explained by Nernst equation and Ag/AgCl electrode potential.
• A linear relationship was observed between SGGT transfer curve shifts and microfluidic flow velocity.
• The SGGT demonstrated potential for sensing flow velocity, ionic strength, or zeta potential when other parameters were known.

Conclusions:

• The Ag/AgCl gate electrode is crucial for the ion-sensitive behavior of SGGTs.
• SGGTs are effective transducers for measuring flow velocity in microfluidic systems.
• SGGTs integrated into multichannel microchips hold significant promise for lab-on-a-chip applications.