Synthesis and characterization of CdSxSe1-x/ZnS alloy core/shell nanocrystals: photoluminescence quantum yield improvement with influence of composition

Abstract

The work presented in this thesis is the first example of alloy core/shell semiconductor nanocrystals. The synthesis of CdSxSe1-x/ZnS core/shells and their analysis by UV-Vis absorption spectroscopy, fluorescence spectroscopy, Rutherford backscattering spectroscopy, and transmission electron microscopy to determine their size, composition, and shelling will be detailed. The quantum yield of the alloy nanocrystals improves dramatically upon shelling, exhibiting an unexpected trend correlating with changing composition. On a practical level, this opens doors for future applications in areas such as biological labeling by allowing further surface functionalization of size and color tunable alloy nanocrystals with higher quantum yields. On a fundamental level, this shelling will allow further insight into origin of the optical properties of the alloy nanocrystals and the effect of composition on alloy fluorescence.