PEDOT percolation networks for reversible chemiresistive sensing of NO₂

Detection of NO₂ plays an important role in various safety applications. However, sensitive and reversible sensing of NO₂ remains a challenge. Here we demonstrate the use of poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymer percolation networks for chemiresistive sensing of NO₂. By adjusting the electrochemical polymerisation and doping conditions of the polymer, we show control over the relative contributions of oxidised and over-oxidised PEDOT to the sensing behaviour. Reversible NO₂ sensors using only PEDOT as the sensor material are demonstrated. By operating the sensor near the electrical percolation threshold, a higher sensitivity is achieved compared to more traditional thin film based chemiresistive sensors. A limit of detection of 907 ± 102 ppb was achieved.