Preparation of ultrafast ammonia sensor based on cross-linked ZnO nanorods coated with poly(3-hexylthiophene)

Abstract

A gas sensing device was fabricated using poly(3-hexylthiophene) (P3HT)-coated ZnO nanorods, and the ammonia (NH3) gas-sensing properties of the heterojunction device were analyzed. Hexagonal ZnO nanorods were prepared using the hydrothermal method on a ZnO seed layer. The ZnO seed layer was deposited using the sputtering method on a Ti–Pt bilayer interdigital electrode. X-ray diffraction and field emission scanning electron microscopy characterized the crystal structure and morphology of the ZnO–P3HT nanorods heterojunction devices. The gas-sensing properties of the P3HT–ZnO nanorods heterojunction sensor were examined and compared with different concentrations of NH3 gas. The response and recovery times were less than 1.5 s with a NH3 gas concentration of 1 ppm. Comparison with sensors of other materials indicated that P3HT was the reason for the short response and recovery times. Plausible mechanisms explaining the enhanced NH3 selectivity of the P3HT–ZnO nanorods heterojunction structure are discussed.