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Rational design of the gram-scale synthesis of nearly monodisperse semiconductor nanocrystals.

Protière M, Nerambourg N, Renard O, Reiss P - Nanoscale Res Lett (2011)

Bottom Line: On the basis of these results, the synthesis has been scaled up by a factor of 20.Using a 2-L batch reactor combined with a high-throughput peristaltic pump, different-sized samples of CdSe nanocrystals with yields of 2-3 g per synthesis have been produced without sacrificing the narrow size distribution.In a similar setup, the gram-scale synthesis of CdSe/CdS/ZnS core/shell/shell nanocrystals exhibiting a fluorescence quantum yield of 81% and excellent resistance of the photoluminescence in presence of a fluorescent quencher (aromatic thiol) has been achieved.PACS: 81.20.Ka, 81.07.Bc, 78.67.Bf.

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Affiliation: DSM/INAC/SPrAM (UMR 5819 CEA-CNRS-UJF)/LEMOH, CEA-Grenoble - 17 rue des Martyrs - 38054 Grenoble cedex 9, France. peter.reiss@cea.fr.

ABSTRACT
We address two aspects of general interest for the chemical synthesis of colloidal semiconductor nanocrystals: (1) the rational design of the synthesis protocol aiming at the optimization of the reaction parameters in a minimum number of experiments; (2) the transfer of the procedure to the gram scale, while maintaining a low size distribution and maximizing the reaction yield. Concerning the first point, the design-of-experiment (DOE) method has been applied to the synthesis of colloidal CdSe nanocrystals. We demonstrate that 16 experiments, analyzed by means of a Taguchi L16 table, are sufficient to optimize the reaction parameters for controlling the mean size of the nanocrystals in a large range while keeping the size distribution narrow (5-10%). The DOE method strongly reduces the number of experiments necessary for the optimization as compared to trial-and-error approaches. Furthermore, the Taguchi table analysis reveals the degree of influence of each reaction parameter investigated (e.g., the nature and concentration of reagents, the solvent, the reaction temperature) and indicates the interactions between them. On the basis of these results, the synthesis has been scaled up by a factor of 20. Using a 2-L batch reactor combined with a high-throughput peristaltic pump, different-sized samples of CdSe nanocrystals with yields of 2-3 g per synthesis have been produced without sacrificing the narrow size distribution. In a similar setup, the gram-scale synthesis of CdSe/CdS/ZnS core/shell/shell nanocrystals exhibiting a fluorescence quantum yield of 81% and excellent resistance of the photoluminescence in presence of a fluorescent quencher (aromatic thiol) has been achieved.PACS: 81.20.Ka, 81.07.Bc, 78.67.Bf.

No MeSH data available.


TEM images and spectra of the final, purified samples. (a, b, c) TEM images of the obtained 4.0-, 5.0-, and 6.7-nm CdSe nanocrystals (from left to right). (d) Corresponding UV-vis absorption spectra; (e) normalized PL spectra (excitation wavelength, 450 nm).
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Figure 3: TEM images and spectra of the final, purified samples. (a, b, c) TEM images of the obtained 4.0-, 5.0-, and 6.7-nm CdSe nanocrystals (from left to right). (d) Corresponding UV-vis absorption spectra; (e) normalized PL spectra (excitation wavelength, 450 nm).

Mentions: The evolution of the absorption and PL spectra of aliquots taken during the gram-scale synthesis is very similar to the laboratory-scale synthesis. The spectra of the final, purified samples (Figure 3d or 3e) exhibit well-defined excitonic peaks in UV-vis absorption and narrow emission linewidths (FWHM 30-32 nm). The narrow size distribution of approximately 7.5% for all three samples is confirmed in the TEM images Figure 3a, b, c. We attribute the general observed size increase in the gram-scale synthesis to the fact that the powerful mechanical stirring influences the nucleation and growth kinetics as compared to the magnetically stirred laboratory-scale synthesis.


Rational design of the gram-scale synthesis of nearly monodisperse semiconductor nanocrystals.

Protière M, Nerambourg N, Renard O, Reiss P - Nanoscale Res Lett (2011)

TEM images and spectra of the final, purified samples. (a, b, c) TEM images of the obtained 4.0-, 5.0-, and 6.7-nm CdSe nanocrystals (from left to right). (d) Corresponding UV-vis absorption spectra; (e) normalized PL spectra (excitation wavelength, 450 nm).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211985&req=5

Figure 3: TEM images and spectra of the final, purified samples. (a, b, c) TEM images of the obtained 4.0-, 5.0-, and 6.7-nm CdSe nanocrystals (from left to right). (d) Corresponding UV-vis absorption spectra; (e) normalized PL spectra (excitation wavelength, 450 nm).
Mentions: The evolution of the absorption and PL spectra of aliquots taken during the gram-scale synthesis is very similar to the laboratory-scale synthesis. The spectra of the final, purified samples (Figure 3d or 3e) exhibit well-defined excitonic peaks in UV-vis absorption and narrow emission linewidths (FWHM 30-32 nm). The narrow size distribution of approximately 7.5% for all three samples is confirmed in the TEM images Figure 3a, b, c. We attribute the general observed size increase in the gram-scale synthesis to the fact that the powerful mechanical stirring influences the nucleation and growth kinetics as compared to the magnetically stirred laboratory-scale synthesis.

Bottom Line: On the basis of these results, the synthesis has been scaled up by a factor of 20.Using a 2-L batch reactor combined with a high-throughput peristaltic pump, different-sized samples of CdSe nanocrystals with yields of 2-3 g per synthesis have been produced without sacrificing the narrow size distribution.In a similar setup, the gram-scale synthesis of CdSe/CdS/ZnS core/shell/shell nanocrystals exhibiting a fluorescence quantum yield of 81% and excellent resistance of the photoluminescence in presence of a fluorescent quencher (aromatic thiol) has been achieved.PACS: 81.20.Ka, 81.07.Bc, 78.67.Bf.

View Article: PubMed Central - HTML - PubMed

Affiliation: DSM/INAC/SPrAM (UMR 5819 CEA-CNRS-UJF)/LEMOH, CEA-Grenoble - 17 rue des Martyrs - 38054 Grenoble cedex 9, France. peter.reiss@cea.fr.

ABSTRACT
We address two aspects of general interest for the chemical synthesis of colloidal semiconductor nanocrystals: (1) the rational design of the synthesis protocol aiming at the optimization of the reaction parameters in a minimum number of experiments; (2) the transfer of the procedure to the gram scale, while maintaining a low size distribution and maximizing the reaction yield. Concerning the first point, the design-of-experiment (DOE) method has been applied to the synthesis of colloidal CdSe nanocrystals. We demonstrate that 16 experiments, analyzed by means of a Taguchi L16 table, are sufficient to optimize the reaction parameters for controlling the mean size of the nanocrystals in a large range while keeping the size distribution narrow (5-10%). The DOE method strongly reduces the number of experiments necessary for the optimization as compared to trial-and-error approaches. Furthermore, the Taguchi table analysis reveals the degree of influence of each reaction parameter investigated (e.g., the nature and concentration of reagents, the solvent, the reaction temperature) and indicates the interactions between them. On the basis of these results, the synthesis has been scaled up by a factor of 20. Using a 2-L batch reactor combined with a high-throughput peristaltic pump, different-sized samples of CdSe nanocrystals with yields of 2-3 g per synthesis have been produced without sacrificing the narrow size distribution. In a similar setup, the gram-scale synthesis of CdSe/CdS/ZnS core/shell/shell nanocrystals exhibiting a fluorescence quantum yield of 81% and excellent resistance of the photoluminescence in presence of a fluorescent quencher (aromatic thiol) has been achieved.PACS: 81.20.Ka, 81.07.Bc, 78.67.Bf.

No MeSH data available.