The research objective of this Faculty Early Career Development (CAREER) Program award is to test the hypothesis that the flexoelectric response can be enhanced by controlling the morphology, the size, and the substrate-induced buckling of inorganic nanomaterials including two-dimensional (2D) atomic layers. In contrast to piezoelectricity, which describes electrical polarization induced by uniform mechanical deformation, electrical polarization induced by strain gradients known as flexoelectricity has long been overlooked due to its relative weakness in bulk ceramics which will rupture before large strain gradients are achieved. Nanomaterials, on the other hand, can survive orders of magnitude higher strain gradient generated by microscale buckling and wrinkling. Recently, enhanced electromechanical coupling at nanoscale has been discovered and was hypothetically attributed to flexoelectricity without direct experimental evidence. The project will be carried by combining experiments with modeling and simulations in four research thrusts: i) flexoelectric response of barium titanate (BaTiO3) nanowires, nanoribbons and nanomembranes on deformable substrates, ii) electromechanical coupling in atomically thin hexagonal boron nitride (h-BN) and molybdenum disulfide (MoS2) supported by deformable substrates, iii) failure mechanisms and fracture mechanics of flexoelectric nanomaterials on deformable substrates, and iv) scaled flexoelectric response by nacre-inspired multilayer stacking.
This research will enable rationalized design, optimization and scaleup of sensors, actuators and energy harvesters based on the principle of flexoelectricity. A central goal of this program is to promote interdisciplinary research and teaching and to expose underrepresented groups to cutting edge interdisciplinary research. The PI will initiate a school-wide interdisciplinary course on "Mechanics and Materials of Flexible and Stretchable Electronics". The PI will provide interdisciplinary research opportunities specifically designed for undergraduate and high-school students from minority institutes through the connections established by the Engineering Research Center (ERC) - Nanomanufacturing Systems for Mobile Computing and Mobile Energy Technologies (NASCENT) and the Women in Engineering Program (WEP) at the University of Texas at Austin. The PI and the students will also prepare demos of wearable stretchable electronics and generators for lab open houses and for university-wide outreach activities. The PI plans to distribute both her research and education outcomes globally via publications, conferences, and online Journal Clubs and videos.
