Effect of chemical composition on luminescence of thiol-stabilized CdTe nanocrystals
1 Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146, Hamburg, Germany
2 Photonics Department, National Institute of Advanced Industrial Science & Technology (AIST), Ikeda, Osaka, 563-8577, Japan
3 Physical Chemistry/Electrochemistry, Technical University of Dresden, Bergstr. 66b, 01062, Dresden, Germany
Nanoscale Research Letters 2007, 2:230-234 doi:10.1007/s11671-007-9052-xPublished: 13 April 2007
Judicious selection of the amount of surfactant during synthesis enables a drastic increase in the photoluminescence efficiency of aqueous CdTe nanocrystals (NCs) stabilized by thioglycolic acid (TGA). Elemental determination of the NCs was undertaken to identify the origin of this effect. The molar ratio of (Te + S) to Cd approached unity when the optimum amount of TGA was used during synthesis, whereas the number of S atoms originating from TGA molecules in one NC (2.6 nm of diameter) remained unchanged at 90 ± 3. This indicates that the core lattice composition at the beginning of synthesis, rather than the surface conditions, affects the photoluminescence efficiency of the NCs even after prolonged refluxing.