| Summary: | 碩士 === 國立臺南大學 === 電機工程學系碩博士班 === 103 === In this study, AgInS2/ZnS quantum dots (AIS/ZnS QDs) and quaternary Cu-In-Zn-S quantum dots were synthesized via non-vaccum process. We used 1-Octadecene (ODE) and polyetheramine (D400) as solvent. AgInS2/ZnS QDs were prepared by 1-Octadecene and Cu-In-Zn-S QDs were prepared by polyetheramine. We successfully synthesized AgInS2/ZnS and Cu-In-Zn-S QDs and use absorption spectra, emission spectra, X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) to analysis the optical properties and the crystal structure of QDs. In the experiment, we control the synthesis temperature to obtain different sizes of quantum dots. In addition, we coated a shell layer of ZnS on QDs to form the structure of core/shell QDs. The results confirmed that by changing the Zn content and the ZnS shell growth time not only can efficiently increase the quantum yield (QY) and Photoluminescence (PL) intensity but also make the emission wavelength blue shift. After the addition of high band gap ZnS, the ion exchange reaction will occurred on the core quantum dots surface, so that the core size of core-shell structure quantum dot will gradually become smaller, it will cause a blue shift.
Finally, we combined QDs and phosphor then package in the light emitting diode, and apply an appropriate external current. Compare with the conventional phosphor- based white LED, the QDs-phosphor based white LED could emit a broad range of colors, so the CRI values will be relatively increased. We also compared the EL characteristics of the QDs-based white LED and general white LED, and the results demonstrate that CRI values of the QDs-based white LED will be higher than phosphor-based white LED.
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