Our mission is to understand the mechanically coupled physical properties of functional materials and engineer the materials from molecular to microscale levels based on the discovered physical-chemical principles to address the grand engineering challenges facing our society, including energy, clean water, and a sustainable environment. We aim to tackle the bottleneck problems at materials interfaces and develop mechanical insights into materials design innovations by combining advanced multifunctional scanning probe microscopy characterization with principles of solid mechanics and surface sciences. We integrate experiments, theory, and simulation to investigate cutting-edge problems in these areas: (1) Interfaces of low dimensional materials; (2) Structure-property relationship of hybrid materials; (3) Multiphysics coupling in functional materials.
Current active research interests include:
1) Advanced Scanning Probe Microscopy Techniques
Scanning probe microscopy (SPM) provides a unique platform to investigate the materials from multifunctional aspects with high spatial and time resolutions, ranging from mechanical, electrical, thermal, optical, and semiconductor properties, which allows one to gain comprehensive insights into the materials under study from different perspectives. We not only are equipped with most commercially available functional property characterization capabilities based on SPM but also continuously develop new functional SPM imaging techniques to push the boundary of scientific research.
2) Interfaces of Low-Dimensional Materials & Thin Films
Modern technology development heavily relies on the integration of functional materials where the interfaces between these materials are always the bottlenecks that limit the device performance. This is extremely the case for low dimensional and thin-film materials, where the surface-volume ratio is very high. Our goals in this research thrust are: 1) Understand the interfacial structure and properties by mechanical and physical characterizations; and 2) design new interfaces to improve the integrated device performances. Particularly, 2D materials offer a unique model system to understand materials interaction happening through the interfaces, where the materials are literally made of two surfaces.
3) Two-Dimensional Hybrid Organic-Inorganic Perovskites
Hybrid organic-inorganic perovskites (HOIPs) rise as next-generation electronic materials with great application potentials in optoelectronics and beyond, yet fully realization of their application potential in the real-world is hindered by their chemical stability. 2D HOIPs not only greatly improved the stability issues facing their 3D counterparts without losing their good electronic properties, but also enable a vast composition space to tailor their physical properties. A comprehensive understanding of the structure-property relationship of this new member of the 2D materials family is essential to achieve materials design principles for desired properties.
4) Piezoelectric and Ferroelectric Materials
Piezoelectric and ferroelectric properties involve the first-order electromechanical coupling, allowing the energy conversion between electricity and elasticity. Such functional properties have been exploited in many appliances in our daily life, and are the fundamental mechanism behind many critical components in scientific instruments. They can be in the form of an actuator, energy harvester, or transducer. At nanoscale, especially in 2D dimensional materials, piezoelectricity/ferroelectricity can be engineered into the materials by symmetry breaking from a bottom-up materials design paradigm. Discovering new piezo- and ferroelectric materials and harnessing their electromechanical coupling properties for energy harvesting in extreme environments are particularly interesting to the group.
Representative Papers: Inorganic Chem. (2017)
5) Mechanics of Soft and Biomaterials