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- Vacassy, R., et al.
(författare)
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Nanostructured zinc sulphide phosphors
- 1998
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Ingår i: Materials Research Society Symposium - Proceedings. ; , s. 369-374
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Konferensbidrag (refereegranskat)abstract
- Zinc sulphide (ZnS) particles are efficient phosphors for application in flat-panel displays. Spherical ZnS particles were prepared by precipitation from a homogeneous solution. Nanoparticles of 20 to 40 nm having a very narrow size distribution could be synthesized by using complexing chelates such as acetate and acetylacetonate. Complexing of the precipitating cation with the anions present in the system lead to a limited concentration of free cations in the solution. This strongly influences the kinetics of the primary particle agglomeration/growth, resulting in nanometer-sized ZnS particles. Nanostructured ZnS synthesized in this way are polycrystalline particles composed of crystallites of 5-10 nm. The synthesis of very small, non-agglomerated, nanocrystalline particles in the 5-10 nm size range was also possible, making use of a strong complexing ligand (thioglycerol) during the synthesis. The synthesis of controlled monosized ZnS particles will be presented and discussed. The photoluminescence characteristics of ZnS make this material a suitable candidate as phosphor for application in low voltage display technology. The effect of Mn2+ doping on the luminescence characteristics of ZnS will also be discussed.
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| 5. |
- Hofmann, H., et al.
(författare)
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Potential of nanosized ceramic powder for functional applications
- 1997
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Ingår i: Ceramic Engineering and Science Proceedings. ; , s. 687-694
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Konferensbidrag (refereegranskat)abstract
- Nanophase ceramic particles are building-blocks for the formation of nanostructured ceramics and are important in a composite for functional applications. Different synthesis methods for nanosized ceramics were developed. Depending on the method and chemical composition, powders which are agglomerates of nanosized primary particles exist. These primary particles show very small grain size distribution.
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| 6. |
- Vacassy, R., et al.
(författare)
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Synthesis of controlled spherical zinc sulfide particles by precipitation from homogeneous solutions
- 1998
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Ingår i: Journal of The American Ceramic Society. - : American Ceramic Society. - 0002-7820 .- 1551-2916. ; 81:10, s. 2699-2705
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Tidskriftsartikel (refereegranskat)abstract
- Zinc sulfide (ZnS) powders have been obtained by precipitation from homogeneous solutions of various zinc salt compounds with S 2- as precipitating anion, formed by decomposition of thioacetamide. Spherical particles with a very narrow size distribution can be obtained by controlling; the synthesis parameters. The particle sizes are influenced by the nature of the associated anion. For example nanometer-sized ZnS particles are formed using acetate or acetylacetonate anions under acidic pH conditions, controlled by the addition of acetic acid. Although the nucleation is accelerated by the use of acetic acid, limited particle growth occurs because of the formation of complexes with zinc cations that lowers the concentration of free cations in the solution. Also, the complexing-attachment phenomena of the ZnS particles with acetate and acetylacetonate anions lead to the arrest of particle growth processes. The presence of complexed Zn 2+ species in the acidic solution is demonstrated both theoretically, using a model based on the calculations of the solubility isotherms of the soluble species, and by Fourier-transform infrared techniques. The nanostructured ZnS particles may provide a suable semi-conductor nanocluster material for optoelectronic applications as well as a phosphor suitable for application in flat-panel display technology.
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- Valmalette, J. -C, et al.
(författare)
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Optical properties of gold clusters precipitated on zirconia particles
- 1998
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Ingår i: Materials Research Society Symposium - Proceedings. - : MRS, Warrendale, United States. ; , s. 85-88
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Konferensbidrag (refereegranskat)abstract
- We have studied precipitation of noble metals with a view to extending these synthetic processes to other metals. In this paper we discuss the synthesis of gold clusters on the surface of oxide fine particles (in the range 60-100 nm). The influence of pH of the solution, the concentration of metal and the reducing agent are discussed. The size distribution of the precipitated gold clusters, determined by transmission electron microscopy, are around 2-10 nm. The interface between the gold clusters and oxide has been investigated by HRTEM. Optical measurements of the zirconia supported gold clusters shows a significant shift in the plasmon resonance. A model based on effective medium theory is proposed taking into account the high refractive index of zirconia.
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