Synthesis and Properties Research of High Quality Quantum Dots
|School||East China University of Science and Technology|
|Keywords||Semiconductor nanocrystals Photoluminescence Nanocrystalline Core / shell structure|
In recent years , the scientific community has developed a variety of excellent performance composite nanocrystalline ( alloy nanocrystals , core / shell structure nanocrystals doped nanocrystalline ) . Today's research trend is towards the development of environmentally friendly , cost -saving , operation Simple direction . Semiconductor Nanocrystals mature process , but also synchronized with the main trend of gradually toward the development of low-cost, non-toxic compounds direction . This article takes a different approach to the synthesis of a high quality core / shell structure CdSe / CdS / ZnS nanocrystals and doped nanocrystalline Mn : ZnS . CdSe / CdS / ZnS nanocrystals , CdSe core preparation process does not involve expensive alkyl phosphorus ( trioctylphosphine , TOP) of highly toxic substances , but directly as a source of selenium selenium powder synthesized sphalerite The mineral structure CdSe nuclear . CdSe core of CdS and ZnS shell growth process using ordinary commercial single molecule precursors CDC ( diethyldithio carbamate cadmium) and the ZDC ( diethyldithiocarbamate dithiocarbamate ) , instead of the past as toxic organic metal precursor material, such as bis (trimethyl vulcanizing silicone ) and diethyl zinc. While in the experimental operation more simple , prepared CdSe and CdSe / CdS / ZnS semiconductor nanocrystalline has high fluorescence quantum yield ( up to 90% organic phase , and transferred to the aqueous phase is still as high as 60% after the MPA ligand exchange . doped nanocrystals Mn : Preparation of ZnS with the nucleation - doping method . prepared Mn : ZnS nanocrystals fluorescence quantum yield of 54% . experimental results show that the preparation of size as small as possible the MnS nuclear is a successful experiment key factors by using a relatively weak complexing power dodecanethiol as a ligand , a suitable reaction temperature , and suitable Mn : S ratio can control the size of the nucleus of MnS , in order to achieve the purpose of the emission peak intensity of the enhanced manganese and inferred through the study of the changes in the spectral characteristics of the CdSe / CdS / ZnS nanocrystals doped nanocrystalline Mn : of ZnS formation mechanism , as well as by TEM, XRD and test methods on the structure of the product was characterized .