Nucleation and Growth Kinetics of PbS Quantum Dots in Oxide Glass: Spectroscopic and Microscopic Studies in the Dilute Range

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• 作者：Swati Joshi ; Sabyasachi Sen ; Patricia C. Ocampo
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：March 22, 2007
• 年：2007
• 卷：111
• 期：11
• 页码：4105 - 4110
• 全文大小：340K
• 年卷期：v.111,no.11(March 22, 2007)
• ISSN：1932-7455

文摘

The kinetics of nucleation and growth of PbS nanocrystals or quantum dots in a boroaluminosilicate hostglass have been studied in the dilute range of the precipitating phase (~2 wt % PbS) using infrared absorptionspectroscopy and transmission electron microscopy. The temperature dependence of the experimental steady-state nucleation rates have been found to be several orders of magnitude lower than the predictions based onthe classical nucleation theory. The induction times for nucleation at various temperatures are found to bemore than 2 orders of magnitude longer than the shear relaxation time scale of the host glass, although theaverage activation energies are found to be similar in both cases (~200 kJ/mol). The growth curves at alltemperatures show an extremely sublinear time dependence of particle radius r ~ t^0.15-0.20 indicating an earlyonset of ripening process which also results in a saturation in the nucleation rate. A strong deviation from thetypical scaling relations of r ~ t^1/2 or t^1/3 has been hypothesized to result from a growth mechanism based oncluster diffusion and attachment.