From rigid to flexible: solution-processed carbon nanotube deposition on polymeric substrates for the fabrication of transistor-based ion sensors

Electrolyte-gated field-effect transistors (EG-FETs) are widely used in the growing field of biochemical sensing applications, due to their manifold advantages, such as large specific capacitance, low operating voltage, and intrinsic signal amplification. In this work, carbon nanotube EG-FET (EG-CNTFET)-based sensors for ammonium (NH + 4 ) detection reported. The active semiconducting single-walled (CNTs) layer was manufactured through a cost-effective scalable spray deposition technique. To achieve high-quality networks, CNT ink optimized. Atomic force microscopy analysis optimize concentration significantly reduce post-treatment time from previously reported 12 h 1 h. optimized then fabricate EG-CNTFETs first on standard rigid Si/SiO xmlns:xlink="http://www.w3.org/1999/xlink">2 substrate flexible polyimide foils. Both devices showed typical p-type behavior with an on-off ratio order magnitude 1×10 xmlns:xlink="http://www.w3.org/1999/xlink">3 A/A. Furthermore, proof concept, we demonstrated NH ions fabricated functionalized nonactin ion-selective membrane. calibration curve linear range 0.01mM 10mM, covering entire physiological concentrations interest, average sensitivity 0.346 μA/decade 94.35% coefficient determination.