Colloidal Synthesis of Hollow Cobalt Sulfide Nanocrystals
Formation of cobalt sulfide hollow nanocrystals through amechanism similar to the Kirkendall Effect has been investigated indetail. It was found that performing the reaction at>120oC leads tofast formation of a single void ins ide each shell, whereas at roomtemperature multiple voids are formed within each shell, which can beattributed to strongly temperature-dependent diffusivities for vacancies.The void formation process is dominated by outward diffusion of cobaltcations; still, significant inward transport of sulfur anions can beinferred to occur as the final voids are smaller in diameter than theoriginal cobalt nanocrystals. Comparison of volume distributions forinitial and final nanostructures indicates excess apparent volume inshells implying significant porosity and/or a defective structure.Indirect evidence for shells to fracture during growth at lowertemperatures was observed in shell size statisticsand TEM of as-grownshells. An idealized model of the diffusional process imposes two minimalrequirements on material parameters for shell growth to be obtainablewithin a specific synthetic system.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of Basic EnergySciences; AirForce Office of Scientific Research Award FA9550-04-1-0065; Generalitat de Catalunya
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 901223
- Report Number(s):
- LBNL-59874; R&D Project: 51MF20; BnR: KC020401C; TRN: US200713%%199
- Journal Information:
- Advanced Functional Materials, Vol. 16; Related Information: Journal Publication Date: 2006; ISSN 1616-301X
- Country of Publication:
- United States
- Language:
- English
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