Zero- versus One-Dimensional Water-Soluble CdTe NanocrystalsSynthesis and Photophysical Characterization
journal contributionposted on 12.07.2007, 00:00 by Christian Schulz-Drost, Vito Sgobba, Dirk M. Guldi
This work demonstrates the systematic development and characterization of water-soluble one-dimensional nanorods of CdTe (QR) with the assistance of a mixed ligand system, namely, a combination of 2-(dimethylamino)ethanethiol and cysteine, that both serve as surface stabilizers. Their characterization has been accomplished by means of a wide range of microscopic and photophysical techniques. The corresponding three-dimensional quantum dots of CdTe (QD) emerged as important reference systems, especially for the different photophysical assays. The latter were exclusively formed when just 2-(dimethylamino)ethanethiol was used as surface stabilizer. A maximum photoluminescence quantum yield of 25% was estimated for QR samples that were refluxed in water for approximately 11 h. Such remarkably high quantum yields, which are appreciably higher than what is seen for the analogous QD, point to a successful control over defects, trapping states, etc. In line with this trend is the observation that the excited-state lifetime of the QR is longer than in analogous QD.