High sensitive surface-acoustic-wave optical sensor based on two-dimensional perovskite

Surface acoustic wave (SAW) optical sensor based on two-dimensional (2D) sensing layer can always provide extremely high sensitivity. As an attractive option, the application of exfoliated 2D perovskite on acousto-optic coupling optical sensor is investigated. In this work, exfoliated 2D (PEA) ₂ PbI ₄ sheet was transferred as a sensing layer onto the delay area of a dual-port SAW resonator with resonant frequency ~497 MHz. From the response under 532 nm laser with intensity of 0.9 mW/cm ² , a largest frequency shift of ~13.92 MHz was observed. The ultrahigh sensitivity up to 31.6 ppm/(μW/cm ² ) was calculated by experiment results. We also carried out theoretical analysis and finite element simulation of 3D model to demonstrate the mechanism and validity for optical sensing. The fabricated optical sensor expressed great potential for a variety of optical applications.