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Posted: June 1, 2006
Analysis of the primary processes in the growth of quantum dot nanocrystals at solid-liquid interfaces
(Nanowerk News) The National Institute of Advanced Industrial Science and Technology (AIST) and Tohoku University 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.
We 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).