Influence of Ethanol and Acetone Vapors on the Properties of Forward and Backward Acoustic Waves in the Structure "YX Lithium Niobate Plate – Higher Fungi Mycelium Film"

The gas-sensitive properties of the forward SH1 and backward A1 acoustic waves in the YX lithium niobate plate loaded with a biofilm based on the mycelium of higher fungi are considered. The possibility of using an acoustoelectronic device based on a single interdigital transducer (IDT) as a gas-sensitive element is shown. In the absence of a sensor coating on the surface of the piezoelectric plate, the S11 parameter of the above waves does not change when exposed to water vapor, ethanol and acetone in the range from 7 to 20 MHz. When a sensor film based on the mycelium of basidiomycetes is applied to the side of the plate free from the IDT, the S11 parameter of the backward wave A1 changes depending on the film thickness. In this case, the value of this parameter for the forward wave SH1 remains unchanged. The magnitude of the change in the S11 parameter when exposed to saturated vapors of the test water sample for the forward wave SH1 is approximately twice as high as for the backward wave A1. However, the lower detection limit of water vapor for the backward wave is 4.32 g/m3, while for the forward wave it is only 7.59 g/m3.