Effect of chromium dopant on electrospun zinc oxide nanostructure: A room temperature ethanol sensor

Nanomaterials-based gas sensors represent a ground-breaking endeavour that establishes a systematic and methodical approach to the detection of deleterious contaminants on a broad scale, particularly within the environmental and healthcare domains. In this context, we have commenced the synthesis of chromium-doped (0, 0.5, and 1 wt%) zinc oxide nanostructures through the utilization of an electrospinning technique, subsequently followed by a calcination process. The resultant chromium-doped zinc oxide nanostructures have been subjected to rigorous analysis, affirming their polycrystalline nature as well as the discernible impact of chromium dopants, as confirmed by the X-ray diffraction pattern. Interconnected irregularly shaped multi-grain particles with higher oxygen adsorption sites were confirmed by scanning electron microscope and X-ray photoelectron spectrometer. After analyzing the electrical and optical features, the fabricated sensing elements were tested for their sensing behaviour at room temperature and found to have a selective response towards ethanol vapour. Among the samples, 0.5 wt% chromium-doped zinc oxide exhibited a sensing response (S = 9.03 for 100 ppm) towards ethanol at room temperature. Additionally, the lower limit of detection was found to be 1 ppm, and the response and recovery times towards 100 ppm of ethanol are 41 & 81 s. Further, a thorough investigation into the influence of chromium dopants on the ZnO lattice has been conducted, revealing their pivotal role in augmenting the gas-sensing characteristics of the material.