AIST Analyses Primary Processes in the Growth of Quantum Dot Nano-crystals at Solid-Liquid Interfaces; Opening Doorway to Clarification of Relationship Between Structures and Functions of Nano-crystals.

Tokyo, Japan, June 2, 2006 - (JCN Newswire) - The National Institute of Advanced Industrial Science and Technology (AIST; Hiroyuki Yoshikawa, President) and Tohoku University (Takashi Yoshimoto, President) have theoretically and experimentally analyzed the crystal nucleation process and the subsequent crystal growth process in the colloidal synthesis of CdSe quantum dots, and succeeded in clarification of the relationship among crystal size, crystal structure, and optical absorption spectra in the primary process of the crystal growth.

Until now, the relationship between the function and the size or structure of quantum dots has been unclear. However, by synthesizing them at temperatures lower than those for conventional methods (below 200 C), the reaction rates were slowed (approximately 40 min), enabling the tracking of the reaction process using optical absorption spectra.

AIST and Tohoku have clearly identified the initial nucleation followed by growth of quantum dot crystals, and moreover clarified the relationship between crystal structures in nucleation and growth, and the optical absorption spectra with the technique of computational chemistry.

To design and fabricate nano-scale electronic materials, it is very important to understand adequately the relationship between the nano-crystal structures realized physically and their functions. In the current work, we have clarified the relationship not only between the crystal size and the wavelength of the absorbed light, but also between the crystal structure and the absorption spectra, thereby enabling the establishment of a method of evaluation of the relationship between the structures and the functions of the nano-crystals. The current work was published in the Journal of the American Chemical Society (February, 2006).

Background of the Current Work

The Health Technology Research Center has developed technologies for real-time imaging of single biomolecules to serve medical diagnosis by detecting disease-related biomolecules. We have developed quantum dot technologies in part of our project, "Development of fluorescent labeling techniques for visualization of biomolecules."

History of Research Work

The Nano-Bioanalysis Team has carried out study on the preparation of fluorescent semiconductor quantum dots such as CdSe, and developed techniques for the labeling of biomolecules and visualization of bio-cells using the quantum dots since 2002, when the former Single-Molecule Bio-Analysis Laboratory was established. We found not only new applications of biomolecules labeled with quantum dots but also a novel synthesis method of quantum dots (patent No. 2004-129843). Furthermore, using the method, we have succeeded in producing quantum dots with novel physical properties useful for fluorescent probes. The current work was supported by the Grant-in-Aid for Scientific Research (KAKENHI) in Priority Area "Molecular Nano Dynamics" from Ministry of Education, Culture, Sports, Science, and Technology, Japan.

Please read details of the current work at the AIST website:

http://www.aist.go.jp/aist_e/latest_research/2006/20060601/20060601.html

About AIST

The National Institute of Advanced Industrial Science and Technology (the new AIST) began operations on April 1, 2001. AIST is a newborn research organization that comprises 15 research institutes previously under the former Agency of Industrial Science and Technology (the former AIST) in the Ministry of International Trade and Industry and the Weights and Measures Training Institute. The new AIST is Japan's largest public research organization with many research facilities and around 3,200 employees in all.

Source: AIST

Contact:

AIST Planning Headquarters
1-3-1, Kasumigaseki, Chiyoda-ku,
Tokyo, 100-8921 Japan
Tel [phone]
Fax [phone]

Copyright [c] 2006 JCN Newswire. All rights reserved. A division of Japan Corporate News Network K.K.