PI-conjugated organic molecules (chromophores) and polymers have a wide potential applications in photovoltaic cells, electro-optic modulation, light emitting diodes, field-effect transistors, etc. The way chromophores and polymers organize (self-assemble) in the solid state largely determines their electrical, optoelectronic, and electro-optic properties. Self-assembly is governed by intermolecular interactions which are in turn determined by polarity and molecular shape/geometry. One major research area of our group is to use molecular shape engineering to control the ways chromophores and polymers self-assembly in thin films in order to maximize their performances in different applications.
Another area of research is about photostability of organic materials. Light absorbing organic materials commonly have low photochemical stability. Study of photodegradation mechanisms of different organic molecules allows us to gain understanding of their photodegradation processes which may lead to new strategies for development of photostable organic materials.
The third area of research is renewable aromatic chemical generation from lignin -- the largest renewable source of phenolic polymers. Due to the complexity of lignin structure and complication by unwanted condensation reactions in solvolysis of lignin, yield of monomeric phenolic compounds is rather 10 (<20%) despite the intensive research in the past few years. In this research, we have two objectives:
- Develop methods for selective cleavage of the most abundant and weakest linkage (beta-O-4) under mild conditions to decompose lignin into oligomers.
Synthesize PF resins and expoxy adhesives using the oligomers and study structure-property relationships.
To achieve above research goals, we develop and apply advanced organic molecular design, organic synthesis knowledge and skills, and product analysis methods, and use a range of experimental tools including nuclear magnetic resonance spectroscopy, various chromatographic methods and instruments, GC-MS, UV-vis/fluorescence spectrometers, thermal analyzers, powder and single crystal XRD, etc.
|Dr. Zhang in front of a fumehood equipped with a rotary evaporation system. Each student working on organic synthesis is provided with such a system.
|A graduate student, Simon Jianyuan Sun, working with a new UV-vis-NIR spectrophotometer.
|The glovebox - frequently used to store and handle moisture/oxygen sensitive chemicals and reactions.|