Ultrasensitive Flexible NO₂ Sensors with Remote-Controllable ADC-Electropolymerized Conducting Polymers on Plastic

Area of Science:

• Materials Science
• Electrochemistry
• Sensor Technology

Background:

• Conjugated macromolecules synthesis via electropolymerization (EP).
• Development of conducting polymer films for gas sensing applications.
• Need for scalable and remote synthesis methods for functional materials.

Purpose of the Study:

• To demonstrate remote synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT):anion sensing films using alternating- and direct-current (ADC) bipolar electropolymerization (EP).
• To evaluate the performance of these films in flexible nitrogen dioxide (NO2) gas sensors.
• To investigate the sensing mechanism behind the observed gas-sensing characteristics.

Main Methods:

• Remote synthesis of PEDOT:anion films on plastic substrates via ADC-bipolar EP.
• Fabrication of flexible NO2 gas sensors using the synthesized PEDOT:ClO3 films.
• Gas-sensing performance evaluation, including sensitivity, cross-sensitivity, and detection limit.
• Spectroscopic analysis, microstructural characterization, and interaction energy computations to elucidate the sensing mechanism.

Main Results:

• PEDOT:ClO3 films exhibited excellent gas-sensing characteristics for NO2.
• Sensitivity of 54.8% to 50 ppm NO2, with a detection limit of 0.726 ppb.
• Minimal cross-sensitivity to other tested gases.
• Enhanced sensitivity attributed to electrostatic interaction between ClO3- and NO2, and the film's hierarchical macrostructures.

Conclusions:

• ADC-bipolar EP is a practical method for the scalable, remote synthesis of functional polymer films.
• The synthesized PEDOT:ClO3 films are promising for flexible NO2 gas sensing.
• Understanding the molecular-level interactions is key to optimizing sensor performance.