Chemiresistive Polymer Percolation Network Gas Sensor Created with a Nanosphere Template
Weishuo Li, Merel J. Lefferts, Yu Wang, Abigail M. Lister, Axel Forssberg, Runze Chen, Liren Wang, Martin R. Castell
Abstract
Abstract The sensitivity and limits of detection (LOD) of chemiresistive gas sensors can often be improved by increasing the surface area of the sensing material that interacts with the analyte. This process is referred to as nanostructuring. Nanostructured polypyrrole (PPy) chemiresistive sensors for ammonia detection were created with the aid of a nanosphere template. Polystyrene nanospheres are deposited to form a template between interdigitated electrodes, and chronoamperometry is then used to grow PPy between the electrodes within the gaps of the nanospheres. The PPy growth is controlled to create electrical percolation networks. After removal of the nanospheres by dissolving them, the percolation behavior and sensing response of the nanostructured PPy sensors are investigated. The nanostructured percolation sensors show higher sensitivity and lower LOD to ammonia than percolation networks prepared without nanosphere templates. An optimal nanostructured ammonia percolation sensor with a chemiresistive sensitivity of 2.59 ± 0.20% ppm −1 and a LOD of 71 ± 6 ppb is obtained.