High-Sensitivity of Self-Powered Gas Sensors Based on Piezoelectric Nanogenerators With Y-Doped 1-D ZnO Nanostructures

In this work, yttrium-doped zinc oxide (Y-doped ZnO) nanorod (NR) arrays were grown using a simple facile hydrothermal solution route at low temperature to fabricate a self-powered gas sensor based on piezoelectric nanogenerator (PENG). The material properties of the 1-D NR arrays were observed using a field-emission scanning electron microscopy (FE-SEM) with an energy-dispersive X-ray (EDX), an X-ray diffraction (XRD), and a high-resolution transmission electron microscope (HR-TEM). The Y-doping concentration in the ZnO NRs was estimated to be 0.96 at%. Photoluminescence (PL) analysis was used to analyze the distribution of oxygen defects in the nanostructures. The Y-doped ZnO NRs were grown onto the bottom substrate and indium-tin-oxide polyethylene terephthalate (ITO-PET) substrates with silver (Ag) electrode were used as the top electrode to fabricate the PENG device. By introducing regular frequency mechanical external forces through a home-made impact system, the ZnO NRs of PENG devices generate piezoelectric effects, then the output electrical characteristics of PENGs were measured. It can be seen that the NRs with a Y-doping concentration of 7.5 mM showed a significant change in output voltage and current when exposed to carbon monoxide (CO) gas. Meanwhile, the Y:ZnO PENGs revealed remarkable sensitivity (58%) in 150 ppm CO environment. As a result, it was seen that such a device exhibited a self-powering characteristic and a significant sensitivity to CO gas. In the future, the device can also be combined with the Internet of Things (IoTs) for CO gas detection (e.g., portable gas sensors).