Realizing Surface Acoustic Wave Device Based on 2D Ruddlesden‐Popper Perovskite: Exploring Acoustic and Acoustoelectric Characteristics

ABSTRACT Here, the first experimental evidence demonstrating the electrical excitation and detection of surface acoustic waves (SAW) in hot cast 2D Ruddlesden‐Popper halide perovskite (RPP) layer ((BA) 2 PbI 4 ) is reported. The observed resonance frequency at around 90 MHz in the radio frequency (RF) transmission and reflection spectra proves the piezoelectric capability of the achieved pinhole‐free RPP layer with close‐packed crystal grains, which are shown to be modifiable by the hot casting temperature. Furthermore, the acoustoelectric phenomenon in this material is explored by illuminating blue (450 nm) light, resulting in a shift of the resonance frequency and SAW attenuation due to the photogenerated free carriers in the RPP layer. Consequently, the realized RPP‐based SAW sensor exhibits an electromechanical coupling coefficient of 2.2%, and a photosensitivity of 2722 ppm (mW cm −2 ) −1 . The presented findings demonstrate that RPPs’ functionality can go beyond optoelectronics, playing a key role in acoustic, piezoelectric, and piezophototronic devices, as well as coupled acousto‐optic components. In this regard, considering the strong excitonic and polaritonic properties of 2D RPPs at room temperature, this study unveils the potential of RPPs for the prospect of SAW‐induced active transport of excitons and exciton‐polaritons, paving the way toward the emerging quantum technologies.