Scientific Results

Growth Mechanisms of CdS Nanocrystals in Aqueous Media

Year: 2012

Authors: Latterini L., Iagatti A.

Autors Affiliation: Department of Chemistry, Center of Excellence for Nanostructured and Innovative Materials (CEMIN), University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy

Abstract: CdS nanocrystals were prepared in water-in-oil microemulsions. The nanocrystal properties, absorption and luminescence spectra and size distributions, were monitored at different times after mixing the microemulsions of the two precursors to obtain information on their growth mechanism. In particular, CdS nanocrystals were prepared using water-in-heptane or water-in-nonane microemulsions. The results obtained from the investigation of nanocrystals prepared using heptane as the organic phase, confirmed that nanocrystal nucleation is fast while their growth is determined by droplet exchange content rate. Size distribution histograms obtained from the sample at early time points after mixing presented a bimodal population having average sizes of 3.0 +/- 0.1 and 5.8 +/- 0.1 nm, thus indicating that surface process controls the nanocrystal growth. With longer reaction times the occurrence of water droplet coalescence is likely responsible for the formation of nanocrystal agglomerates. Using a water-in-nonane microemulsion, the droplet exchange rate can be modified, thus leading to smaller CdS nanocrystals. However, the development of structural defects cannot be excluded, as evidenced by the luminescence spectra of the suspension. In general, aging of the nanocrystal in the pristine microemulsion resulted in the development of cubic semiconductor nanostructures.

Journal/Review: CRYSTALS

Volume: 2 (2)      Pages from: 618  to: 626

More Information: Authors thank the Minister for the University and Scientific Research (MIUR, Rome) and the University of Perugia for the financial support.
KeyWords: CdS nanocrystal; microemulsion; luminescence; dimension distributions; TEM
DOI: 10.3390/cryst2020618

Citations: 2
data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2022-01-23
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