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About Our Team

Research topics

Dr. Yi Du and Dr. Xun (Joe) Xu:

2D materials, catalysis and liquid metal, superconductor

Dr. Si Zhou:

Computer-aided exploration and design of low-dimensional materials

Mr. Haifeng Feng, Ms. Yani Liu, Ms Mengting Zhao:

2D materials, surface catalysis

Mr. Long (Chris) Ren, Ms. Nana Liu, Ms. Guyue Bo

Catalysis and liquid metal

Dr. Nana Wang

Lithium/Sodium batteries

STM team is under the supervision of A/Prof. Yi Du and Dr. Xun Xu.

STM team members include four research fellows, six PhD candidates, and one visiting student.

The front row, from left to right: Miss Yani Liu, Miss Guyue Bo, Miss Ningyan Cheng, Ms Dandan Cui, Miss Nana Liu;

The back row, from left to right: A/Prof. Yi Du, Dr. Haifeng Feng, Dr. Long (Chris) Ren, Dr. Xun (Joe) Xu.

Fetured Works

STM/2D Materials

--by Haifeng Feng

We have successfully fabricated monoatomic assembled single Sn adatoms on the surface of NbTe2, which is confirmed by STM measurement. It was found that well-ordered 3 × 2 and 3 × 3 superstructures with respect to the unit cell of NbTe2 substrate prevail on the surface, which is modulated by the peculiar CDW in NbTe2. As CDWs widely exist in the TMDs materials, this method provides a prevalent way to build monoatomic adatoms on the surface of TMD materials. More importantly, with the monoatomic Sn adatoms on the surface its surface electronic property changes from semimetallic to metallic state. Therefore, these suggest a very promising way of modifying the surface electronic properties, which will benefit the charge transfer during electrocatalytic reactions. As Sn is well known as an excellent electrocatalyst both for reducing CO2 and for modifying the catalytic activity and selectivity of other catalysts, the monoatomic Sn adatoms are expected to act as active sites on the surface of NbTe2 in additional to modification of the surface electronic structure.

Realization of Strained Stanene by Interface Engineering-by Yani Liu

Stanene, the tin analogue of graphene, has been predicted to be a two-dimensional topological insulator, providing an ideal platform for the realization of the quantum spin Hall effect even at room temperature. Here, continuous stanene has been successfully formed on the Au(111) substrate, and its crystalline structure, phonon properties, and electronic structures are investigated by scanning tunneling microscopy and in-situ Raman spectroscopy combined with first-principles calculations. The surface Sn-Au alloy with a coverage-dependent structural evolution is first identified. At coverage above a critical value of 0.33 monolayer, a surface alloying-to-dealloying transition is observed, where the Au-Sn alloy is gradually converted into epitaxial stanene with a √3×√7 superstructure. Distinctive vibrational phonon modes are discovered in √3×√7 stanene through in-situ Raman, which are correlated with the tensile strain evoked by its singular buckled structure. Our results present clear evidence for the existence of epitaxial stanene and provide a platform for exploration of the exotic properties of this strained two-dimensional material.

Liquid metals and Batteries

Liquid metals and their hybrids as smart electronic materials--by Long Ren

The future of electronics is believed to be soft, elastomeric, miniaturized, and biocompatible. Exploration of soft and biocompatible electronic materials that respond to the environmental changes and manifest their own functions according to the optimum conditions will undoubtedly be an essential task in the development of smart materials and the smart electronic system. Conventional, rigid materials including stiffness metal and dielectric ceramics remain the key electronic building blocks of most modern smart electronic devices, but show limited abilities towards to the soft smart electronics. Among the large number of smart materials, the term “soft” is well presented by the field-responsive fluids that typically divided into magnetorheological fluids and electrorheological fluid. However, the fluids carriers used in these smart fluids are usually non-conductive, being the barrier for the smart electronics.
The re-emergence of room temperature liquid metals (LMs) presents an exciting paradigm for an ideal combination of metallic and fluidic properties. The unique fluid metal features of non-hazardous Ga-based LMs, including high surface energy, low viscosity, electrical and thermal conductivity, a wide temperature range of the liquid state, and desirable chemical activity for many applications, have led to remarkable possibilities for harnessing their properties and achieving unique functionalities. The realization of their stimulus-responsivity and multi-functionality make Ga-based LMs an attractive family of ‘smart materials’ that could act as the basis of countless applications in new frontiers, covering a wide range from materials science and engineering to medicine. Constructing hybrids of Ga-based LMs with other functional materials can further extend the field-responsive capacity of liquid metals to incredible levels.
We have already done some works on preparation of LM nanostructures and investigation of the related physical and chemical properties. We have also studied Ga-based LMs’ stimulus-responsive behaviors and developed the corresponding potential devices with liquid metal-based nanodroplets and hybrids, including developing superconductive LM nanodroplets for printable superconducting electronics, mechanical adaptable LM bio-electrodes, and photo-response flexible electronics. Further exploration will be focused on photo-/electro-/thermal- induced LMs’ stimulus-responsive behaviors, and applying to the fields ranging from catalysis, energy storage, sensors, and bio-devices. There is a long way to go for advancing LM-based smart materials that can be nearly as good as the one shown in the ‘Terminator’ movie series. The aim of our research in this field is not to make the science-fiction fact, but once similar achievements have been made, revolutionary advances in materials science, as well as ubiquitous applications relevant to electronics, optics, materials science, chemistry, and medicine can be gained.

Economical electrode materials for safe metal-ion batteries--by Nana Wang

My current research focused on design, synthesis, and characterization of novel materials for secondary metal-ion batteries. Boosting the metals (sodium, lithium, or potassium) storage through defects engineering, structural engineering, and interface engineering. Studying the relationship between ion transport, electrode thickness, electrode conductivity and the energy density of the batteries.