A new synthesis method of colloidal ZnSe nanocrystals exhibiting size-dependent optical properties is reported. The ZnSe quantum dots are prepared in a non-coordinating solvent (octadecane) via direct reaction of zinc stearate with selenium dissolved in trioctylphosphine, i.e., without the use of pyrophoric reagents. The photoluminescence of the resulting nanocrystals can be tuned in the spectral range 390-440 run with constant emission linewidths of the order of 15 nm. (C) 2003 Elsevier B.V. All rights reserved.