Potassium Iodide-Functionalized Polyaniline Nanothin Film Chemiresistor for Ultrasensitive Ozone Gas Sensing

Area of Science:

• Materials Science
• Environmental Science
• Analytical Chemistry

Background:

• Polyaniline (PANI) nanostructures are sensitive to atmospheric pollutants.
• PANI nanothin films on microelectrodes show promising sensing performance.
• Ozone (O₃) detection is crucial for environmental and occupational safety.

Purpose of the Study:

• To develop and evaluate a PANI nanothin film chemiresistive sensor modified with potassium iodide (KI) for ozone detection.
• To investigate the sensitivity, selectivity, and sensing mechanism of the KI-PANI sensor for ozone.

Main Methods:

• Electropolymerization of PANI nanothin films on microelectrodes.
• Modification of the PANI film with potassium iodide (KI).
• Chemiresistive sensing measurements for ozone (O₃), nitrogen dioxide (NO₂), and sulfur dioxide (SO₂).

Main Results:

• The KI-PANI sensor demonstrated excellent sensitivity to O₃ in the 8–180 ppb range, with a limit of detection of 230 ppt.
• The sensor exhibited high selectivity against NO₂ and SO₂.
• The sensing mechanism involves iodometric chemistry, where O₃ reacts with KI to produce triiodide (I₃⁻), doping the PANI film and increasing its conductivity.

Conclusions:

• The KI-PANI nanothin film sensor offers a highly sensitive and selective method for ozone detection.
• The sensor's performance highlights its potential for practical applications in environmental monitoring and occupational safety.