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Abstract:
　　Perovskites include a family of functional materials with ABX₃ structure. Barium titanite (BaTiO₃) is a typical inorganic ferroelectric perovskite that possesses switchable spontaneous polarization. Ferroelectric polarizations are usually switched by electric field, but other forms of switching mechanisms have been demonstrated, such as flexoelectricity, pyroelectric effect, and change of chemical environment. In this talk, our recent works of MoS₂-facilitated optical illumination induced polarization switching of BTO thin film will be reported. Based on the interplay between the photoelectric behavior of MoS₂ and the build-in field in BTO, relatively low energy UV light can cause polarization switching of BTO underneath the MoS₂ flakes from upward to downward direction in the MoS₂/BTO heterostructures. Another type of perovskites attracted much attention in recent years is the hybrid inorganic-organic perovskite materials. We recently discovered an intriguing property of this type of materials, which is the large electrostrictive response of MAPbI₃ showing compressive strain of approximately 1%. It enables the material to be used as actuators or other kinds of electromechanical systems in addition to solar cell applications.  

Biosketch： 
　　Tao Li, Ph.D. is an associate professor at Xi’an Jiaotong University at School of Materials Science and Engineering, affiliated with the State Key Laboratory for Mechanical Behavior of Materials and the Center of Spintronics and Quantum System, where she joined in 2018. She obtained her bachelor and Ph. D. degrees from the National University of Singapore in 2009 and 2013 respectively, and had spent 3 years at the University of Nebraska-Lincoln in United States for the postdoctoral research. One of her current research interests is the interface effects and photoelectric coupling behaviors of the heterostructures of 2D materials/ferroelectric thin film for nonvolatile memory applications, mainly investigated using various Scanning Probe Microscopy (SPM) techniques. Her expertise is in the multifield coupling and in-situ materials and devices characterizations using SPM. She has spent years in the fields of ferroelectric-based nonvolatile digital memories, inorganic-organic hybrid perovskite solar cells, and electromechanical coupling of calcified tissues, to investigate their complicated nanoscale phenomena and mechanisms.