This thesis describes a novel approach for the synthesis of p-type semiconductive polypyrrole (PPy) nanoparticles, based on polyvinyl pyrrolidone (PVP)-assisted micelle formation. This approach is simple, facile and environmentally friendly. The PPy nanoparticles of uniform size and shape were readily integrated with interdigitated microelectrode arrays for sensitive photo and chemical gas sensors....[ Read more ]

This thesis describes a novel approach for the synthesis of p-type semiconductive polypyrrole (PPy) nanoparticles, based on polyvinyl pyrrolidone (PVP)-assisted micelle formation. This approach is simple, facile and environmentally friendly. The PPy nanoparticles of uniform size and shape were readily integrated with interdigitated microelectrode arrays for sensitive photo and chemical gas sensors.

PPy nanoparticles-based sensing devices were fabricated via a simple drop casting of PPy nanoparticles on the interdigitated microelectrode arrays. Based on the internal photoelectric effect of the PPy nanoparticles, the performance of the PPy nanoparticles-based sensing device as an UV illuminance meter was investigated. It was found that the limit of detection was 2 Lux and the sensitivity was 3.425% per Lux of UV light illuminance. The PPy nanoparticles-based sensing device was also tested as an ammonia gas detector, based on the un-doping process of the PPy nanoparticles. The limit of detection was found to be 4 ppm and the sensitivity determined to be 0.274% per ppm ammonia in the concentration range from 0 ppm to 100 ppm, which covers the ammonia threshold limit values (25 ppm and 35 ppm), as defined by American Conference of Governmental Industrial Hygienists (ACGIH). Furthermore, the enfluence of the size of PPy nanoparticles and the thickness of the PPy nanoparticle layer on the sensitivity of the sensing device was investigated. It was found that smaller PPy nanoparticles lead to higher sensitivity, while the thickness of the PPy nanoparticle layer does not affect the sensor performance.

The novel PPy nanoparticle synthesis approach developed in this study represents a progress towards simpl, cheap and environmentally friendly production of nanostructured conductive polymers. The obtained PPy nanoparticles demonstrate a high potential in finding application in a wide range of technologies such as photo detection and chemical gas sensing.