tailieunhanh - Báo cáo hóa học: " Facile synthesis of monodisperse ZnS capped CdS nanocrystals exhibiting efficient blue emission"

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 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 . 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 . 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 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 .