Resistive room temperature DMA gas sensor based on the forest-like unusual n-type PANI/TiO2 nanocomposites

TiO2 gas sensors have been limited to apply in some gas detection processes due to their high working temperature. Compositing conductive polymer is a workable strategy to decrease the working temperature. Here we present a resistive gas sensor based on PANI/TiO2 nanocomposite to detect dimethylamine (DMA) at room temperature. The TiO2 nanorod arrays were assembled on the surface of the sensor device by a hydrothermal method first, and then polyaniline was grown on the surface of the TiO2 nanorod arrays by a low-temperature gas phase diffusion method. By changing the diffusion time of polyaniline, the conductivity type of PANI/TiO2 nanocomposites can change from n-type to p-type. When deposited for a short time, the PANI/TiO2 nanocomposite reflects the characteristics of n-type semiconductor TiO2. The sensing test results show that the PANI/TiO2 sensor exhibits high response (6.36-30 ppm), high selectivity and good linearity to DMA at room temperature (25 degrees C), and the lowest concentration for DMA detection reaches 0.050 ppm. When deposited for a long time, the PANI/TiO2 nanocomposite exhibits the characteristic of the p-type semiconductor PANI, and the response to 30 ppm DMA at room temperature is 1.47. This provides a new strategy for the detection of DMA at room temperature, which will also promote the application of low temperature detection of semiconductor sensors.

Automated summary

A resistive gas sensor based on PANI/TiO2 nanocomposite was developed to detect dimethylamine (DMA) at room temperature. The sensor shows high response, high selectivity, and good linearity to DMA, with the lowest detection concentration reaching 0.050 ppm. The conductivity type of PANI/TiO2 nanocomposites can be changed from n-type to p-type by adjusting the diffusion time of polyaniline.