Tai Huiling

The fabrication and optimization of OTFT formaldehyde sensors based on Poly(3-hexythiophene)/ZnO composite films

Formaldehyde (HCHO), a colorless and pungent-smelling gas, is confirmed be a huge threat to human health. The detection of formaldehyde is necessary and important. The Poly(3-hexythiophene) (P3HT)/ZnO organic-inorganic composite thin film was fabricated and used as the sensitive layer of organic thin film transistors (OTFT) by spray-deposited method to detect HCHO at room temperature. The process parameters such as P3HT/ZnO weight ratios and airbrushed masses were optimized. The results showed that P3HT/ZnO OTFT exhibited good sensing response to HCHO. Airbrushed mass of 1ml was the optimal mass, and the 1:1 and 1:5 weight ratios of P3HT/ZnO exhibited better sensing properties compared with others. OTFT gas sensors based on P3HT/ZnO composite film provides a novel promising approach to the detection of HCHO.

Preparation of bilayer/three-layer PEO-carbon nanotube composite thin films and their toluene-sensing application

The bilayer poly (ethylene oxide)/multiple-walled carbon nanotubes (PEO/MWCNTs) and three-layer PEO/MWCNTs/PEO composite thin films were fabricated with the spraying process on the interdigitated transducers (IDTs) as gas sensors for toluene-sensing application. Compared with the bilayer thin film sensor, the sensor with three-layer thin films exhibited higher response values and better recovery property. The microstructures of sensing films were characterized by scanning electron microscopy (SEM) to indicate that the better sensing response of three-layer thin films might be ascribed to the sufficient adsorption of toluene molecules on the surfaces of upper and bottom PEO films. The selectivity of the three-layer film sensor was further investigated by comparing responses upon exposure to different interference vapors with the response to toluene exposure, and much higher response was observed in the case of toluene. Good repeatability of the three-layer film sensor was also observed.