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Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Facile synthesis of monodisperse ZnS capped CdS nanocrystals exhibiting efficient blue emission | Nanoscale Res Lett 2006 1 62-67 DOI 10.1007 S11671-006-9001-0 NANO EXPRESS Facile synthesis of monodisperse ZnS capped CdS nanocrystals exhibiting efficient blue emission Myriam Protiere Peter Reiss Published online 25 July 2006 to the authors 2006 Abstract A new method for the capping of colloidal CdS nanocrystals with ZnS shells is presented. A combination of the monomolecular precursor zinc ethylxanthate Zn ex 2 and zinc stearate was used to replace hazardous organometallic reagents usually applied in this procedure i.e. bis trimethylsilyl sulfide and diethylzinc. Its simple preparation air-stability and low decomposition temperature of 150 C make Zn ex 2 a very suitable source for the ZnS shell growth. With this precursor highly luminescent CdS ZnS core shell nanocrystals Q.Y. 35-45 exhibiting narrow emission linewidths of 15-18 nm FWHM in the blue spectral region can reproducibly be obtained. Keywords Semiconductor nanocrystals CdS ZnS Fluorescence Blue emission Introduction Since the discovery of the quantum confinement effect 1 colloidal semiconductor nanocrystals have been intensively studied due to their unique sizedependent physical properties. In particular cadmium based systems CdSe CdTe CdS have drawn much attention as a consequence of the development of M. Protiere CEA Grenoble DRT LITEN DTNM L2T 17 rue des Martyrs 38054 Grenoble cedex 9 France P. Reiss El CEA Grenoble DSM DRFMC SPrAM UMR 5819 CEA-CNRS-Universite Joseph Fourier 1 LeMoH 17 rue des Martyrs 38054 Grenoble cedex 9 France e-mail peter.reiss@cea.fr several powerful synthetic methods for the preparation of monodisperse samples. The original organometallic synthesis 2 with pyrophoric dimethylcadmium as the metal precursor has found interesting alternatives in more recent preparation methods based on cadmium alkylphosphonates or cadmium carboxylates 3 often referred in literature as green-chemical syntheses. The capping of nanocrystals with another semiconductor is a well-established method .
