Flexible Chemiresistive Nitrogen Oxides Sensors Based on a Nanocomposite of Polypyrrole- Reduced Graphene Oxide Grafted Carboxybenzene Diazonium Salts.

Abstract Nanocomposites of polypyrrole/reduced graphene oxide (PPy/rGO) and polypyrrole/ functionalized reduced graphene oxide with aryl 4-carboxybenzene diazonium salt (PPy/rGO-aryl-COOH) were prepared through covalent bonding by simple one-step chemical oxidative synthesis. The as-prepared nanocomposites were deposited on BOPET substrate by spin coating to test their chemiresistive sensitivity properties on a homemade modular for online detection of (NO2) vapors at ambient temperature. Results showed that PPy/rGO-aryl-COOH forms a homogeneous nanocomposite within the size of 80 nanometers and improvement of the crystalline ordering. The more enhanced NO2 sensing properties have been shown by PPy/rGO- aryl-COOH in terms of higher sensitivity (1.01%/ppm), the faster response time (129 s), and the detection limit of (2ppm). Reproducibility features were also investigated.Moreover, humidity rates and temperature effects were also tested. Finally, impedance spectroscopy is conducted in the fresh air and in the presence of gas. These results highlight the paramount role of functionalization of reduced graphene oxide (rGO-aryl-COOH).