Synthesis and characterization of layered organic/inorganic hybrid thin films based on molybdenum trioxide with poly(N-methylaniline) for VOC sensor

A layered organic/inorganic hybrid thin film consisting of MoO3 with poly(N-methylaniline) (PNMA) was prepared as a VOC sensor. The MoO3 thin films were deposited by chemical vapor deposition. Ion-exchangeable sodium ions were inserted into MoO3 interlayers by reduction process. The (PNMA)xMoO3 hybrid thin film is formed by an intercalation process to ion-exchange sodium ions for PNMA into MoO3 interlayers. The (PNMA)xMoO3 hybrid grains being oriented highly on substrate surface are observed by X-ray diffraction and field-emission scanning electron microscopic analyses. The sensing sensitivity of (PNMA)xMoO3 hybrid thin film to acetaldehyde is as high as that to formaldehyde, whereas typical organic/MoO3 hybrids, polyaniline/MoO3, show a higher sensitivity to formaldehyde than to acetaldehyde, indicating that organic/MoO3 hybrids can be controlled by modifying the interlayer organic components.