Flexible self-powered ammonia sensor based on Ce-ZnO composite film

Abstract

In this work, a flexible self-powered ammonia (NH₃) sensing system based on a vertical contact-separate mode triboelectric nanogenerator (TENG) has been proposed for room temperature detection of NH₃ concentrations. By integrating NH₃-sensing materials into the nanogenerator (TENG), the degree of ambient NH₃ concentration can be actively detected at room temperature. The output voltage of the self-powered system has a proportional relationship with NH₃ concentrations. Furthermore, the Ce-ZnO heterostructure nanoparticles thin film was prepared by hydrothermal synthesis method under 150°C and then form a sensitive film through spray method, which demonstrates a good sensing-response when exposed to NH₃ molecules. For comparison, the ZnO nanoparticles was prepared through the same method. Moreover, the morphology and chemical properties of the fabricated sensor based on ZnO nanoparticles and Ce-ZnO heterostructure nanoparticles film were characterized by SEM, UV-visible spectroscopy and XRD, respectively. In addition, the prepared self-powered triboelectric NH₃ sensor based on Ce-ZnO heterostructure nanoparticles composite thin film holds a gas-sensing response of 44.68% at 100 ppm NH₃. The doping of Ce in the hydrothermal synthesis process of ZnO nanoparticles effectively enhanced the active sites of ZnO, leading to an increase of the NH₃-sensing response compared to pure ZnO nanoparticles film, which is 4.4 times higher than that of pure ZnO. This research not only provides a simple method in self-powered NH₃ sensing but also successfully realizes the integration of NH₃-sensitive materials in the TENG to achieve integrated compatibility in NH₃ detection.