Synthesis of CdSe nanoparticles in the presence of aminodextran as stabilizing and capping agent.

Water-dispersible Amdex-CdSe nanoparticle complexes with sufficient luminescence intensity were prepared at room temperature by rapidly mixing aqueous solutions of either sodium selenide or selenourea with those of cadmium chloride in the presence of amino-derivatized polysaccharides (Amdex) as stabilizing agent. It was shown that the size of CdSe crystallites decreased with increasing content of the polymer in the precipitation process. When present in a sufficient amount, Amdex was found to be an effective stabilizing and capping agent, producing CdSe nanocrystals of weak-to-medium luminescence intensity (maximum room temperature quantum yields of 15-16%). Furthermore, Amdex has proven to be an effective protective agent against photochemical degradation.