Investigation of surface oxidation mechanism for core-shell nanocrystals and exciton dynamics study

• Main Authors: Yeh, Chang Wei, 葉常偉
• Other Authors: Chen, Hsueh Shih
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/77586033039747576703

碩士 === 國立清華大學 === 材料科學工程學系 === 104 === In this study, we investigate the oxidation mechanism of CdSe-ZnS core-shell nanocrystals (NCs). First, the CdSe-ZnS core-shell NCs can be synthesized with different ZnS shell thickness (8 and 18 nm). The quenching mechanism for the CdSe surface defects can disappear by the the formation of the zinc element on CdSe surface. Second, research shows the NCs may release the elemental Zn and S after the oxidation process and cause the surface damage. Finally, the NCs are surrounded a sulfur-based and oxide compounds and decrease the NCs performance. Due to the above factors, the quantum yields (QY) decrease 78% and 38% for both 8 and 18 nm ZnS-capped CdSe NCs.