| Summary: | 碩士 === 國立交通大學 === 應用化學系碩博士班 === 104 === Herein, a series of II-VI semiconductor core/shell QDs were synthesized by a two-step method (CdSe/CdS, CdSe/ZnSe, CdSe/CdS/ZnS, CdSe/ZnS,CdZnSe/CdS, and CdSeS/CdS). The reaction conditions were mild by adopting less toxic and less expensive reactants (cadmium oxide, S powder, Se powder, and zinc stearate) and passivating ligands (stearic acid, oleic acid, hexadecylamine,octadecylamine and trioxylphosphine oxide) instead of hazzardous organometallic precursors. Different conditions of various reaction temperatures and feeding ratios of Cd to Se were tested to accomplish the best CdSe cores for further shell decomposition. For shell growth, successive ion layer adsorption and reaction (SILAR) method offered a successful deposition of shell materials onto purified cores to avert homogeneous nucleation. Shell grew under moderate temperature (200 °C) in order to alleviate the alloy formation between the interface of core/shell and abate serious PL emission red-shift. The resulting PL spectra exhibited sharp peaks for most core/shell QDs and FWHM less than 40 nm, indicating satisfactory control of size distribution. After shell growth, the PL QY was significantly enhanced, especially for gradient alloy ternary cores. The resulting cores and core/shell QDs emitted light from yellow-green to red colors. This versatile synthetic methodology providing highly quality, high QY, and low-cost core/shell QDs opens a door to their applications in display and solar cells.
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