| 1. |
- Scholz, S. M., et al.
(författare)
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Mie scattering effects from monodispersed ZnS nanospheres
- 1998
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 83:12, s. 7860-7866
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Tidskriftsartikel (refereegranskat)abstract
- Transmission spectra of monodispersed particles exhibit pronounced resonance features from which particle properties can be deduced. ZnS powders were used as model materials since they can be synthesized by homogeneous precipitation with a narrow size distribution. The optical extinction spectra can be simulated using Mie scattering theory, and can be used as an in situ diagnostic tool for following the growth of particles during precipitation reactions. Using results of particle diameter measurements by other methods, information on the refractive index of the particles can be retrieved, indicating a highly porous internal structure of the spheres. Distinct features in the experimental and simulated spectra have been interpreted as to arise from circumference and diameter resonance effects in the particles. The simultaneous observation of these two effects allows one to estimate size and solid volume fraction from simple transmission spectra by application of an effective-medium model for the simulation parameters. The potential of application of Mie resonance effects for selective light screening or as pigments are discussed.
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| 2. |
- 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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