石墨烯量子點在二氧化矽之螢光特性及其發光薄膜之應用

石墨烯量子點(GQDs) 擁有一些獨特的光物理性質及材料特性，這些特性是從二維的石墨烯材料本身繼承而來，也可以通過量子局限效應的角度去解釋。此外，GQDs可以通過由上而下的氧化切割或化學合成，基於碳量子點在地球的豐沛性使其成本較低，因此普遍認為可以成為目前應用中含有重金屬的傳統螢光量子點(Quantum Dot,QDs)的替代品。然而，為了製備高效的發光太陽能聚光器（LSCs），目前較為缺乏紅色發光的 GQDs 及高發光且透明的奈米複合材料。在本論文中，我們首先研究了溶解在不同極性溶劑中的邊緣功能化GQDs的光物理性質。我們發現溶劑在 GQDs 的光物理性質中起到相當重要的作用，這可能是由於溶劑導致不同分散度的分子間相互作用而影響發光位置。此外，使用溶膠-凝膠法製備 GQDs摻雜的膠體玻璃，將GQDs（溶於乙酸乙酯和丙酮）和異氰酸酯 - 矽烷的溶膠進行混合反應。通過這種方式，可以獲得發光且透明的 GQDs@silica 奈米複合材料，它可以在固態下提供穩定且有效的紅光發射。通過仔細控制溶膠-凝膠條件，還可以製備無裂紋的 GQDs 摻雜二氧化矽材料，可有效應用於環保 LSCs 和固態照明。

關鍵字

紅色螢光；太陽能聚光器；石墨烯；量子點

並列摘要

Graphene quantum dots (GQDs) exhibit several unique photophysical and materials properties, which can be either inherited from two-dimensional graphene or introduced by quantum confinement effect. In addition, GQDs can be prepared based on cost-effective, earth-abundant precursors by top-down oxidation cutting or chemical synthesis, thus would be promising alternatives for conventional heavy-metal-containing QDs in diverse optoelectronic applications. However, there is still lacking of highly luminescent and transparent nanocomposites based on red-emitting GQDs, which would be beneficial for preparing efficient luminescent solar concentrators (LSCs). In this thesis, we first studied the photophysical properties of edge-functionalized GQDs dissolved in the solvents with different polarity. We found that the solvents play important roles in photophysical properties of GQDs possibly due to intermolecular interaction of distinct dispersion degrees.In addition, GQD-doped silica gel glasses were prepared using sol-gel reaction based on GQDs (dissolved in ethyl acetate and acetone) and isocyanate-silane coupling agents. In this way, luminescent and transparent GQDs@silica nanocomposites were obtained, which can provide stable and efficient red emission in the solid state. By carefully controlling the sol-gel conditions,crack-free GQDs-doped silica monoliths can be also prepared, which would be applied for eco-friendly LSCs and solid-state lighting.

並列關鍵字

red luminescence ； LSCs ； graphene ； QDs

參考文獻

[1]Enghag, P. (2008).Encyclopedia of the elements: technical data history processing applications. John Wiley Sons.

Google Scholar

[2]Wang, Y., (2011). Carbon dots of different composition and surface functionalization: cytotoxicity issues relevant to fluorescence cell imaging. Experimental Biology and Medicine, 236(11), 1231-1238