Virtual design of flexoelectric sensor for electronic skin

Soft electronic devices are indispensable for the development of artificial skin due to their high stretchability and sensing functionality. Conventionally, to mimic touch and temperature sensing of mechanoreceptors and thermoreceptors, compliant structural design accompanied with signal transduction mechanism such as piezoresistive, capacitive, piezoelectric, pyroelectric sensing have been utilized so far. The design of these pressure sensors requires highly flexible and robust electrical properties of materials as active and supporting components. In addition, strategically engineered micro-structure is employed to enhance the sensing performance. In this spirit, flexoelectric material, which relates strain-gradient and electrical polarization, emerges as a naturally suitable candidates for flexible pressure sensors. The strain-gradient-induced polarization does not only distinguish flexoelectricity from the commonly used piezoelectricity but also widen the choice of electro-mechanical coupling materials, especially lead-free and bio-compatible materials that are crucial for the development of biomedical devices. Furthermore, flexoelectric effect exhibits size-dependent behavior, particularly at sub-micron- and nano-scale so that proper design of micro-structure can open an opportunity to a new type of pressure sensor. Therefore, this project aims to propose a novel design for electronic skin (e-skin) based on flexoelectric effect. Specifically, a comprehensive virtual design framework including simulation, characterization and experimental testing of flexoelectric-based sensor will be employed to evaluate key parameters such as sensitivity, limit of detection, linearity, response time and power consumption.