Glycine sensor based on 1D defective phononic crystal structure

Phononic crystals (PnCs) provide an innovative platform for sensing biomaterials. In this work, we introduce a defective 1D-PnC from lead-epoxy multilayer with a central defect layer filled with glycine. The transmission spectra of the incident acoustic wave are calculated numerically by the transfer matrix method. The working principle of this sensor is to sense how much change occurs in the concentration of glycine. Any change in glycine concentration affects the acoustic properties of glycine directly. Thereby the central resonance frequency in the transmission spectrum shifted. In this study, we firstly made optimization for the type of the structure (symmetric/asymmetric), the number of periods, the glycine layer thickness, and glycine concentration to get the best sensor performance. The proposed sensor provided high sensitivity (S = 969.973 kHz) over just a molar ratio range 0–0.383 mol/L. Moreover, we calculated other performance parameters such as the quality factor, which reached a maximum value of 13,497, sensor resolution of 3.49 × 105 Hz, and figure of merit of 4.2. Based on the obtained results, this sensor has many merits such as it is designed from low cost materials, the ease of fabrication, high sensitivity, and absence of any electronic component in its design.