Nanoscale Phase Transformation
Nanoparticles with sizes approaching the molecule scale start to show physicochemical properties deviated from their bulk material form. Instead, mesoscopic effect rises because of their attributes as a complex system. I combine theoretical treatments as well as atomic-scale correlated characterization techniques to study the structural relationships and phase transformation mechanisms inside individual nanoparticles. These efforts may extend our understanding on the nanoscale thermodynamics.
Observation of Soft-Hard Interfaces and Dynamics
I develop and use electron microscope-compatible liquid cells with either silicon nitride or graphene thin films or both as window and sealing materials. I use these technologies to study 1) nanoparticle growth and transition mechanisms during wet chemical synthesis, 2) interactions and collective behaviors of organic and organic/inorganic hybrid nanostructures, 3) dynamics of cells and microbes. These studies may provide critical information to the understanding of how complex structural evolution and interactions happen in a wet environment.
Materials Synthesis with Attoliter-Scale Confinement
Bottom-up fabrication of nanostructures and new materials has been facing with the dilemma of quality and quantity. This includes accurate shaping and positioning of structures, and fabrication both with high resolution and in large scale. Moreover, many recently discovered or developed materials are even not compatible with the standard photolithography processes. As a result. it has been difficult to integrate them into circuits and devices, with many materials staying in a proof-of-concept stage as individual units. I develop and utilize surface patterning techniques to generate attoliter-scale volumes on surfaces. I study and control how materials with desired composition, structure and morphology are generated in such a highly-localized environment. This may further advance nanofabrication of devices with novel materials and structures to a higher level.
Synthesis of Hybrid Nanostructures from Solution
Noble metals such as Pt, Pd, Au are very interesting materials in the industry and applied sciences due to their unique properties in catalysis, plasmonics, etc. Thus, much efforts have been paid to the development of noble metal-based materials for energy, environment, sensing and biomedicine. Now with the development of wet chemical synthesis, we can control the structure, composition and morphology of nanoparticles, in order to further improve their performance in a quantitative nature. Also, it is important to understand deeply about the physics and chemistry behind it. I worked on the synthesis of metallic and multimetallic nanocrystals for plasmonics (can be used as highly sensitive SERS sensor substrate to detect trace amount of organic molecules) and oxygen reduction (can be used as low-cost, highly active and durable electrode materials in fuel cells). I also actively investigated the thermodynamics and kinetics in the nanoparticle formation in order to develop better control of their crystallography and morphology.
The significance of oxides and hybrid structures combining metals and oxides lie in many fields such as energy applications, environmental protection and the electronic industry, which has attracted much research effort in recent decades. Metal/Oxide hybrid nanostructures are not only interesting in science, but also promising in industrial applications with highly performance, due to the existence of strong metal-substrate interaction (SMSI) effect. I have been focused on designing metal/oxide nanostructure in order to provide both high catalytic activity and thermal stability, which are essential problems in many applications of heterogeneous catalysis. I have also worked on oxide materials for oxygen evolution as high performance anode material for electric/photovoltaic-driven water splitting.
With the help of the electronic technologies, most modern flowmeters with high accuracy are based on ultrasonic. The original “beam deviation” method was replaced by the “time-of-flight” (TOF) method decades ago because the former one is limited by its low sensitivity and accuracy. TOF relies on ultra-accurate measurement of time intervals, which makes it difficult in small scale or extreme environments (such as highly fluctuated temperature). Using the principle of wave interference in ultrasonic flowmeter/anemometer can significantly improve its sensitivity and accuracy, meanwhile avoid the measurement of time intervals.
Remote Telescope System
This is also part of the program “Hangzhou-Aksu High School Observatory” by Hangzhou Board of Education. I designed the overall architecture and wrote the main components of the control system.
- Terminal Automation Batch Language Environment for Telescopes (TABLET)
- TABLET is a language to control remote telescope systems. This open-source project offers a core parser, a server, and a client SDK for TABLET distributed under GPLv2. Some old stable versions have already been deployed in our remote telescope systems. Unfortunately, now I don’t have enough time to continue the development.