Synthesis and optical properties of water soluble ZnSe nanocrystals

ZnSe nanocrystals are prepared in water by a wet chemistry method. By selecting an appropriate pH value and surface-capping agents, a whitish blue fluorescence peaking at 470 nm is observed under UV irradiation. The intensity of this fluorescence increases dramatically under reflux and saturates after similar to 40 hrs. The final mean size of the ZnSe nanocrystals measured by transmission electron microscopy is about 2 nm in diameter. The quantum efficiency of the fluorescence from the final solution is estimated to be similar to 1%, although the preparation conditions have not yet been completely optimized. These properties are discussed in comparison with those of similarly prepared CdTe and differently prepared ZnSe nanocrystals.