Chem. Mater., 15 (22), 4300 -4308, 2003. 10.1021/cm034729t S0897-4756(03)04729-X
Web Release Date: October 3, 2003

Copyright © 2003 American Chemical Society

Formation and Stability of Size-, Shape-, and Structure-Controlled CdTe Nanocrystals: Ligand Effects on Monomers and Nanocrystals

W. William Yu, Y. Andrew Wang, and Xiaogang Peng*

Department of Chemistry & Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701

Received August 5, 2003

Abstract:

The formation of nearly monodisperse CdTe nanocrystals-dots (either zinc blende or wurtzite crystal structure), rods, and tetrapods-in a noncoordinating solvent was studied. Several strong ligand effects were observed, and the ligand effects on the monomers were found to play a more important role than the ligand effects on the nanocrystals. Experimental results suggest that, instead of monomer concentrations, monomer activities is a more relevant term for understanding the formation of nanocrystals because strong ligands always exist in the reaction solutions. The bonding strength and the steric effects of ligands dramatically affect the reactivity of monomers and are considered as contributors to the activity coefficients of monomers. The overall optical properties of the as-prepared CdTe nanocrystals are better than those reported in the literature and comparable to the standard CdSe nanocrystal system. The configuration of the hydrocarbon chains of the ligands on the surface of each nanocrystal also plays a critical role in determining the stability of CdTe nanocrystals.


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