Method A. Five grams of dodecylamine (DDA) were
dissolved in 7 mL of tri-n-octylphosphine (TOP) at 50 °C in a
50 mL two-neck flask with a reflux condenser attached. Subsequently,
0.11 mL (1.47 mmol) of dimethylcadmium and
0.128 g (1 mmol) of tellurium powder were added under stirring,
and the temperature was slowly increased to 180 °C. After 30
min, the temperature was raised to 200 °C, and growth of the
nanocrystals was allowed to proceed at this temperature for
20 h. Under these conditions, tellurium slowly dissolves in the
reaction mixture, resulting in a very slow growth of CdTe
nanocrystals at sufficiently high temperatures. Finally, toluene
was added to the warm solution, and the mixture was left for
24 h at room temperature under stirring.
This method allowed obtaining CdTe nanocrystals in the size
range of 4.0-6.0 nm, emitting from yellow to red with
extremely high PL quantum yields exceeding 60%