Scharlau Professor
Department of Chemistry
This e-mail address is being protected from spambots. You need JavaScript enabled to view it.

Research Interests:

Colloidal Nanocrystals: Chemistry and Applications

As one of the major driving forces for modern chemistry, advanced materials are currently of great interest to many chemists. This research group is focused on nano-materials, which are a class of very promising advanced materials. Although thousands of papers reported the preparations of various kinds of nano-materials, the relevant fundamental chemistry for their synthesis and manipulation is still the limiting point for many fundamental studies and technical applications. The goals of our research include: (1) to accumulate systematical chemistry knowledge for designing and processing nano-materials, especially inorganic nanocrystals and related materials; (2) to develop technically useable nano-materials and devices.

(A) A new generation of solar cells. Solar energy is the best energy source, in terms of environment and availability. According to the National Photovoltaic Research Plan (1995-2000), the limitation is the cost of current technology. This research project is developing new, inexpensive, but high performance solar cells by taking advantage of the excellent possibility of inorganic semiconductor nanocrystals and nanostructures.

(B) Growth mechanism of inorganic nanocrystals. Crystallization is a very common process for materials preparation, characterization and processing. However, the existing theories cannot predict and explain crystallization processes systematically. Because of this, our understanding of growth mechanism of inorganic nanocrystals is very limited, which consequently makes it very difficult to design a controllable synthesis. However, the surface energy, which is the driving force of any crystallization process, is very significant ONLY in the nanometer regime. Therefore, a quantitative understanding of the growth of inorganic nanocrystals is possible. Furthermore, we believe that this study will eventually provide a framework for modern crystallization chemistry.

(C) Greener chemical synthetic approaches. Colloidal nanocrystals are of great interest for both fundamental research and industrial applications. The cost and safety for the production of those novel materials will play a key role in the future development of those materials. For this reason, this group is pursuing synthetic chemistry which not only generates high quality nanocrystals but also is environmentally-benign, inexpensive, safe and user-friendly. Such efforts greatly rely on the understanding of the growth mechanisms of colloidal nanocrystals.

(D) Interfacial chemistry of a colloidal nanocrystal and its surroundings. Common interface or surface must be studied using very sensitive, expensive and normally destructive detection apparatus. However, the specific surface area of colloidal nanocrystals is magnitudes higher than that of the corresponding bulk solids. As a result, the interface can be studied using typical solution phase methods in a non-destructive manner. Such studies will serve as model systems for the corresponding bulk solids. Furthermore, the development of the processing chemistry of colloidal nanocrystals has to be based on the knowledge regarding the interface.

(E) Ligands chemistry. Colloidal nanocrystals are metastable species and often coated by a monolayer of organic ligands. The processing of colloidal nanocrystals generally means manipulating the ligands monolayer. We are interested in the development of reliable and feasible processing chemistry based on the rational design of adequate ligands for different types of colloidal nanocrystals.

(F) Chemistry problems for biosensors using colloidal nanocrystals. This research direction is another example to utilize the fundamental knowledge for the advancement of certain types of nanotechnologies. We are exploring the related chemistry for the development of better, more convenient, and less expensive biosensors. For example, a very important issue is to establish chemical methods for the preparation of inorganic nanocrystals with defined number of binding sites for the biological targets.