Flexible and high performance ammonia sensor based on self-assembled PANI-TiO2-Au ternary composite film

Abstract

In this work, a flexible ammonia (NH₃) sensor was prepared by depositing PANI-TiO₂-Au ternary composite film on polyimide (PI) substrate with gold interdigital electrodes through an integrated method of in situ chemical oxidation polymerization and electrostatic self-assembly technique. The morphology, structure, and chemical features of the PANI-TiO₂-Au ternary composite film were characterized by scanning electron microscopy (SEM), atomic force microscope (AFM), ultraviolet-visible absorption spectrometer (UV-Vis), and X-ray photoelectron spectroscopy (XPS). And the NH₃ response performances and flexibility of the PANI-TiO₂-Au sensor were evaluated at room temperature. results showed that the PANI-TiO₂-Au ternary composite film with hierarchical-structure was deposited on the PI successfully. And, the flexible PANI-TiO₂-Au sensor presented high response (89.7%-184.4%) and short response times (52 s-131 s) for 10-50 ppm NH₃, and it also displayed relatively stable response and ultra-low detectable concentration after 1000 bending/extending cycles, which should probably benefit from the good adhesion and flexibility of the PANI-TiO₂-Au ternary composite film. Therefore, the flexible PANI-TiO₂-Au sensor holds great promise for application into hand-held or wearable electronic devices for NH₃ detection.