MXene-Based Flexible Substrate Integrated Waveguide Acetone Gas Sensor

This article presents a microwave sensor utilizing an MXene-coated flexible substrate integrated waveguide (SIW) cavity for detecting acetone gas in environmental monitoring and industrial safety applications. The interaction between MXene (Ti3C2Tx) and acetone (C3H6O) was analyzed using density functional theory (DFT). The analysis revealed that Ti3C2Tx exhibits p-type behavior, leading to a reduction in its overall conductivity. The SIW cavity is designed at fundamental mode (TE101) resonating at 8.12 GHz, using polydimethylsiloxane (PDMS) as the substrate, and the top surface is coated with MXene. When the sensor is exposed to acetone gas, its resonant frequency increases due to a reduction in conductivity caused by electron donation from acetone to Ti3C2Tx, and this resonant frequency shift is used to measure the concentration of acetone gas. A comparative analysis with volatile organic compound (VOC) gases, such as acetaldehyde (C2H4O), ethylene (C2H4), formaldehyde (CH2O), toluene (C6H5CH3), benzene (C6H6), and methanol (CH3OH), is also presented, highlighting the sensor’s exceptional selectivity to acetone. A maximum resonance frequency shift of 40 MHz per 1 ppm is observed, showcasing the sensor’s superior performance in acetone detection.