| Semiconductor quantum dots(QDs)have attracted much attention in biomedical applications in recent years because of their unique physical and chemical properties.Although there have been many research reports of Cd Se QDs,the toxicity of Cd Se QDs limited their application in biological and optoelectronic devices.InP QDs are a good alternative to Cd Se QDs because of big exciton Bohr radius and large absorption coefficient,wide wavelength tunability,low toxicity and environmentally friendly.However,InP QDs were difficult to prepare due to its strong covalence,and the prepared QDs have low luminescence efficiency when compared with cadmium selenide.Therefore,optimizing the InP QDs synthesis procedure and improving the luminescence performance of QDs still are the main research interests at present.Furthermore,QDs with near-infrared emissions have good prospects in the biological imaging due to their strong penetration ability in tissues.However,the application of QDs in biological imaging also requires to solve the problems such as biocompatibility and cytotoxicity of QDs.Considering the above questions,the main work of this article are as follows:(1)InP core was prepared by using tris(dimethylamino)phosphine as phosphine source,and was coated with zinc selenide and zinc sulfide as effective passivation shell.By optimizing the process of multilayer shell coating,InP/ZnSe S/ZnS QDs were obtained with luminous efficiency up to 63%.(2)The near-infrared emitting InP/ZnS QDs were prepared by inhibiting Oswald ripening reaction through multiple injection of precursors.The reaction temperature and reaction time were also optimized,and the final QDs were obtained with emission wavelength of 713 nm.(3)The InP QDs were coated with silica by reverse microemulsion method and sol-gel method.The silica nanoparticles containing InP QDs with fluorescence efficiency up to 17% were obtained,which is expected to be used in biological imaging. |
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