The support of the National Science Foundation and the Army Research Office are acknowledged with gratitude. We also acknowledge Dr. V. Zaikovskii of the Boreskov Catalysis Institute for high resolution TEM studies.
Nanoparticles Prepared by Salt Vapor-Solvent Vapor Cocondensation and Controlled Nucleation: Metal Sulfides (ZnS, CdS, CdSe, PbS), and Metal Halide (LiF). Size, Aggregates, Structures, Digestive Ripening, Superlattices, and Impregnations†
Article first published online: 23 OCT 2007
Copyright © 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Advanced Functional Materials
Volume 17, Issue 17, pages 3562–3568, November, 2007
How to Cite
Heroux, D., Ponce, A., Cingarapu, S. and Klabunde, K. J. (2007), Nanoparticles Prepared by Salt Vapor-Solvent Vapor Cocondensation and Controlled Nucleation: Metal Sulfides (ZnS, CdS, CdSe, PbS), and Metal Halide (LiF). Size, Aggregates, Structures, Digestive Ripening, Superlattices, and Impregnations. Adv. Funct. Mater., 17: 3562–3568. doi: 10.1002/adfm.200700373
- Issue published online: 22 NOV 2007
- Article first published online: 23 OCT 2007
- Manuscript Revised: 11 MAY 2007
- Manuscript Received: 30 MAR 2007
- National Science Foundation
- Army Research Office
A versatile method for the production of gram quantities of nanocrystals of metal sulfides and metal halides has been developed, based on vaporization of the bulk materials followed by controlled nucleation of the molecular vapor species in cold solvent matrices (cocondensate). This approach worked well with ZnS, CdS, CdSe, CdTe, SnS, PbS, and LiF as examples, and is applicable for a large number of semiconductors, ionic salts, as well as metals. Choice of solvent (polar or non-polar), vaporization rate, and rate of warm-up of the cocondensate (period of nucleation) allows some control of crystallite size, aggregate size, and surface area. Interestingly, polar solvents lead to smaller nanocrystals, but larger, less porous aggregates. Also, molar mass of the molecular species has an effect on crystallite size, with heavier molecules giving smaller crystals, apparently due to slower migration in the warming cocondensate. Studies of sintering temperature and crystal growth have shown the nanocrystals are quite thermally stable. Addition of ligands, such as thiols, followed by heating in solvent (digestive ripening) has allowed more monodisperse materials to be formed. Finally, this molecular vapor synthesis approach can be used for impregnating semiconductors (CdS, CdSe) of controlled crystal size on solid supports, such as TiO2 or SiO2.