硒化鎘/硫化鋅核殼量子點之製備、相轉移 、包覆與其在生化及光電領域之應用

Abstract

半導體量子點具有窄頻寬發光與光穩定性等獨特的材料特性，適合應用於生化及光電領域。本論文使用低毒性與低成本的前驅物取代傳統高毒性的有機金屬化合物，以高溫熱注入法製備一系列不同發光波長的高效能硒化鎘/硫化鋅核殼量子點，並在反應溫度、反應時間、前驅物計量與純化次數等製程參數尋求最佳化的合成條件；本研究亦探討核殼量子點的晶體結構、粒徑大小、發光與光譜特性、量子效率與發光衰減壽命等特性。 我們以相轉移方式將親水性硫醇進行疏水性核殼量子點表面改質，繼而評估並篩選高亮度的親水性量子點與鏈親和素鍵結，形成對生物素具有辨識能力的錯合物，並將此錯合物與A549人類肺癌細胞結合，再以共軛焦顯微影像進行螢光訊號分析，確認量子點成功於細胞中細胞質區域顯影，本研究探討了不同硫醇修飾核殼量子點於顯影效果的差異。此外，本研究以聚甲基丙烯酸甲酯直接包覆疏水性核殼量子點，透過分層點膠技術，將紅綠藍及紅黃藍兩種組合作為混成白光的要件，結合波長450 nm藍光LED晶片進行封裝，並比較兩者封裝後的色溫、演色性與光視效能等特性。

Quantum dots (QDs) generally refer to semiconductor with particle size smaller than their radius of Bohr exciton. QDs exhibit unique luminescent properties such as narrow emission band width and demonstrate photostability that are suitable for bioassays and optoelectronic applications. Starting with less toxic and lower cost precursors instead of traditional highly toxic organometallics and using hot-injection method, we have prepared a series of high-performance CdSe/ZnS core-shell QDs different emission wavelengths. Moreover, in order to facilitate subsequent studies, the regulation of reaction temperature, reaction time, the amount of precursors used and purification process were utilized to determine the optimal conditions. We have also investigated the crystal structure, particle size, photoluminescence spectra, quantum yield and decay lifetime of core-shell CdSe/ZnS QDs. Furthermore, the surface modification of hydrophilic CdSe/ZnS QDs was carried out through phase transfer technique by encapsulation with hydrophilic thio molecules. Then, selected hydrophilic QDs with highest brightness was allowed to conjugated to streptavidin, forming a complex having biotin recognition capability, which was found to bind to the A549 human lung cancer cell, which can be characterized with confocal microscopy to observe fluorescence imaging. Our observations confirm that the QDs was present in the intracellular cytoplasm and this research also explored and evaluated the difference in efficiency of thiol-modified hydrophilic QDs used in bioimaging. For white-light LED packaging and fabrication, hydrophobic core-shell CdSe/ZnS QDs with red/green/blue and red/yellow/blue were selected as a hybrid combination of white-light elements and encapsulated with poly (methyl methacrylate), which were then integrated with blue-LED with emission at 450 nm through the layer-by-layer stratified dispensing technique. The color temperature, color rendering index, and luminous efficacy of the two white-light LEDs were determined and compared.