Dissertation > Industrial Technology > General industrial technology > Materials science and engineering > Special structural materials

Synthesis and Properties Research of High Quality Quantum Dots

Author ChenGuanJiao
Tutor ZhongXinHua
School East China University of Science and Technology
Course Applied Chemistry
Keywords Semiconductor nanocrystals Photoluminescence Nanocrystalline Core / shell structure
CLC TB383.1
Type Master's thesis
Year 2011
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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 .

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