Electro-Optical Properties Of Giant Core/Shell Quantum Dots

Due to good optical properties, such as controllable fluorescence and optical stability, semiconductor quantum dots are worth researching further and have promising furture in basic research and applications areas, for example, optoelectronics devices, biomarkers and so on. Based on the CdSe/CdS core/shell quantum dots as research objects, this dissertation is focused on three parts as following:First of all, giant CdSe/CdS core/shell quantum dots were synthesized by successive ionic layer adsorption and reaction (SILAR) method. X-ray diffraction, fluorescence and absorption spectra, fluorescence lifetime and fluorescence blinking curves of the samples were measured. And the dependencies between microstructure and optical properties of giant CdSe/CdS core/shell quantum dots and their shell thickness were studied.Second, cyclic voltammetry (CV) curves of bare CdSe quantum dots were measured by electrochemical method. Highest occupied molecular orbit (HOMO), lowest unoccupied molecular orbital (LUMO) and the dependenies between electrochemical bandgap and optical bandgap of the samples were discussed. Cyclic voltammetry (CV) curves of CdSe/CdS core/shell quantum dots were measured also. The experiment results demonstrate that the trend of electrochemical bandgap runs against that of optical bandgap with the increase of the shell thickness.Finally, pure wurzite CdSe/CdS core/shell quantum dots were prepared by injecting the mixture of cation and anion precursor using constant flow pump at high temperature. And periodic cross Au electrodes were prepared by UV lithography and the optical modulation device based on quantum confined Stark effect was preliminarily discussed.