Quantum size effects of in situ generated colloidal cadmium sulfide particles in dioctadecyldimethylammonium chloride surfactant vesicles
| Autor: | Janos H. Fendler, Heribert J. Watzke |
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| Rok vydání: | 1987 |
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| Zdroj: | The Journal of Physical Chemistry. 91:854-861 |
| ISSN: | 1541-5740 0022-3654 |
| DOI: | 10.1021/j100288a019 |
| Popis: | CdS particles were in situ generated in the presence of dioctadecyldimethylammonium chloride (DODAC) surfactant vesicles. Four different methods of preparations were investigated. In preparation A, CdS particles were generated from CdEDTA/sup 2 -/ distributed both at the inner and outer vesicle surfaces. CdS particles were localized only in the inner or at the outer surfaces of DODAC vesicles in preparations B and C, respectively. Preparation of D involved the generation of CdS from Cd/sup 2 +/ ions electrostatically repulsed from the DODAC vesicle surfaces. Depending on the method of preparation and the stoichiometrical amounts of H/sub 2/S added, CdS semiconductor absorption edges were found to range from 478 to 385 nm, corresponding to particle diameter variations between >50 and 22 A. Using surfactant vesicles as hosts for semiconductors has a number of advantages. They provide differential sites for CdS formation, shift the equilibrium between nucleation and particle growth toward the former, stabilize the growing particles along with the anions present (Cl/sup -/, OH/sup -/, EDTA/sup 2 -/, and SH/sup -/), and, most importantly, allow a convenient control of particle sizes and size distributions. The smallest sized CdS particles with the narrowest size distribution were obtained in preparation A. Smaller sizedmore » DODAC-vesicle-entrapped CdS particles were shown to undergo more efficient, photosensitized electron transfer to methylviologen than larger ones.« less |
| Databáze: | OpenAIRE |
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