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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.

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.


PL intensity in presence of a fluorescence quencher. Comparison of PL intensity before and after addition of 0.015 mL of a 0.5 M solution of 4-methylbenzenethiol (MBT) in chloroform to CdSe core and CdSe/CdS/ZnS core/shell/shell nanocrystals in hexanes (1 mL; excitation wavelength, 400 nm).
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Figure 6: PL intensity in presence of a fluorescence quencher. Comparison of PL intensity before and after addition of 0.015 mL of a 0.5 M solution of 4-methylbenzenethiol (MBT) in chloroform to CdSe core and CdSe/CdS/ZnS core/shell/shell nanocrystals in hexanes (1 mL; excitation wavelength, 400 nm).

Mentions: The powder X-ray diffractagramm of the CdSe/CdS/ZnS nanocrystals (Figure 5) exhibits peaks whose positions lie between those characteristic of pure wurtzite CdSe and those of pure wurtzite CdS and ZnS, which is expected for the CdSe/CdS/ZnS core/shell/shell system. In order to test the quality of the shell, an aromatic thiol (4-methylbenzenethiol), known to act as an efficient fluorescence quencher, was added to the core and core/shell/shell nanocrystals. For the CdSe core nanocrystals, no PL signal is measurable after addition of the quencher, while the core/shell/shell sample retains more than 80% of its initial PL intensity (Figure 6).


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

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

PL intensity in presence of a fluorescence quencher. Comparison of PL intensity before and after addition of 0.015 mL of a 0.5 M solution of 4-methylbenzenethiol (MBT) in chloroform to CdSe core and CdSe/CdS/ZnS core/shell/shell nanocrystals in hexanes (1 mL; excitation wavelength, 400 nm).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 6: PL intensity in presence of a fluorescence quencher. Comparison of PL intensity before and after addition of 0.015 mL of a 0.5 M solution of 4-methylbenzenethiol (MBT) in chloroform to CdSe core and CdSe/CdS/ZnS core/shell/shell nanocrystals in hexanes (1 mL; excitation wavelength, 400 nm).
Mentions: The powder X-ray diffractagramm of the CdSe/CdS/ZnS nanocrystals (Figure 5) exhibits peaks whose positions lie between those characteristic of pure wurtzite CdSe and those of pure wurtzite CdS and ZnS, which is expected for the CdSe/CdS/ZnS core/shell/shell system. In order to test the quality of the shell, an aromatic thiol (4-methylbenzenethiol), known to act as an efficient fluorescence quencher, was added to the core and core/shell/shell nanocrystals. For the CdSe core nanocrystals, no PL signal is measurable after addition of the quencher, while the core/shell/shell sample retains more than 80% of its initial PL intensity (Figure 6).

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.