UC Riverside

Polyaniline (PANI) nanostructures have been widely studied for their sensitivity to atmospheric pollutants at ambient conditions. We recently showed an effective way to electropolymerize a PANI nanothin film on prefabricated microelectrodes, and demonstrated its remarkable sensing performance to be comparable to that of a one-dimensional nanostructure, such as PANI nanowires. In this work, we report further progress in the application of the PANI nanothin film chemiresistive sensor for the detection of ozone (O₃) by modifying the film with potassium iodide (KI). The KI-PANI sensor exhibited an excellent sensitivity to O₃ (8⁻180 ppb O₃ concentration rage) with a limit of detection of 230 ppt O₃, and exquisite selectivity against active chemicals such as nitrogen dioxide (NO₂) and sulfur dioxide (SO₂). The sensing mechanism of the sensor relied on iodometric chemistry of KI and O₃, producing triiodide ( I 3 - ) that partially doped and increased electrical conductivity of the PANI film. The sensitivity and selectivity of the KI-functionalized PANI film demonstrates the potential use for KI-PANI-based O₃ sensing devices in environmental monitoring and occupational safety.