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  • 學位論文

奈米碳材料之製備與其在鋰離子電池和LED之應用

Synthesis and Applications of Nano Carbon Materials: Li-ion Batteries and Light-emitting Diodes

指導教授 : 劉偉仁

摘要


環保對現在來說是很重要的課題,科技的發展與運用雖然提升了人類物質的生活品質,但同時也產生了許多新的問題,像是在發展過程中造成環境上的汙染,所以在此研究論文中,我們開發了綠色能源材料,希望在科技發展過程中,既能提升人類生活品質也能夠兼具環保。 本研究中主要分為兩大主題,分別是石墨烯的製備並應用於鋰離子電池作為負極材料,以及萃取天然黃柏螢光粉材料應用於白光LED。由於傳統製備石墨烯之過程需要大量的酸、鹼、氧化劑等,其對環境上有極大的傷害,首先本研究透過機械法將奈米碳管製備石墨烯奈米片(GNFs)以及以低溫破碎法將石墨脫層為寡層石墨烯(FLG),此兩種方法既簡單,在製備過程中也無須添加額外的化學藥品,所製備之GNFs其片徑約為50 nm,為奈米尺寸也具有石墨烯量子點之特性,進一步探討其發光特性,以340 nm激發GNFs,其放光為465 nm藍光,此外,也透過第一原理計算從CNTs到不同形狀之GNFs其邊界形成能,得到六角形為較為穩定存在之形狀。寡層石墨烯(FLG)是由低溫連續式破碎機脫層而得,透過2000 bar進行破碎3次,其FLG高達85%以上之厚度約為5 nm,層數約為10層,更進一步將FLG作為鋰離子電池石墨烯負極材料進行電性測試,相較於石墨,FLG有較薄的厚度,在高電流(5C)充放電下仍然保有322 mAh/g電容量,石墨在5C充放電下僅僅只有240 mAh/g,FLG在高電流充放電下具有較佳的電性。 本研究的另一個主題為無稀土離子之黃色螢光粉,透過萃取天然中藥材黃柏中的螢光材料,可被nUV與藍光所激發,黃柏螢光粉其放光為540 nm的黃光,與商品YAG:Ce3+其放光波長560 nm相近,其半高寬為120 nm、CIE色度座標為(0.41, 0.55),以380 nm n-UV激發黃柏螢光粉與商品YAG:Ce3+螢光粉,其放光強度為商品的139%,此外,我們將黃柏螢光粉添加至白光LED中並且部分取代商業的紅色螢光粉 (CaSiAlN3:Eu2+),封裝後白光LED其色溫為3616 K、CIE色度座標為 (0.40, 0.40),且可透過添加不同黃柏螢光粉的含量控制其色溫與CIE色度座標,由結果顯示,黃柏螢光粉取代稀土螢光粉於白光LED上具有應用潛力。

並列摘要


Environmental protection is a very important issue for now. For the sake of response these situations, several research efforts have been carried out and elaborated. In this thesis, we propose two methods to synthesize graphene nano-flakes (GNFs) and few layer graphene (FLG) by using cost-effective and chemical free method. For GNFs, the results indicated that the size of as-synthesized GNFs was approximately 40-50 nm. Furthermore, we also use first principles calculations to understand the transformation from CNTs to GNFs from viewpoints of the edge formation energies of GNFs in different shapes and sizes. The corresponding photoluminescence of GNFs are carried out in this study. A green, facile, low-cost and scalable industrial method using jet cavitation (JC) is utilized to prepare few layer graphene (FLG) through natural graphite delamination in deionized (DI) water. This research probes the effects of critical experimental parameters. JC method provides massive production of FLG with high yield using initial concentration of 10 wt.% under various high jet pressures (200 MPa). It revealed that up to 85% of the prepared FLG were less than 5 nm thick and most of FLG were belong to 10 layers by atomic force microscopy (AFM) analysis. Moreover, the delaminated of FLG might be applied as potential anode materials in the LIB. In this study, we test the graphene-based (FLG) anode material for lithium ion battery. We disclose a rare-earth free and yellow-emission phosphor, Phellodendron, which could be both excited by near ultraviolet light and blue light. The new yellow phosphor is obtained by extraction of Phellodendron chinense Schneid. The emission wavelength, full width at half maximum and CIE coordinates of extracted Phellodendron are 540 nm, 120 nm and (0.41, 0.55), respectively. The corresponding luminescent properties of Phellodendron are characterized by PL, PLE, reflection spectra, FITR and decay lifetime. Surprising thing is luminous intensity of Phellodendron phosphors excited at 380 nm was stronger than YAG:Ce3+ phosphor by more than 139%. In addition, we firstly introduce the yellow phosphor in white LED fabrication by combining blue chip and YAG:Ce3+ phosphor, to create warm white. For comparison, red-emission CaAlSiN3:Eu2+ phosphors are also introduced for LED package tests. The results demonstrate that Phellodendron is a potential candidate for white LED applications.

參考文獻


135 Cheng, X., Zhong, J., Meng, J., Yang, M., Jia, F., Xu, Z., Kong, H. & Xu, H. Characterization of multiwalled carbon nanotubes dispersing in water and association with biological effects. Journal of Nanomaterials 2011, 14 (2011).
197 Choi, M. S., Yuk, D. Y., Oh, J. H., Jung, H. Y., Han, S. B., Moon, D. C. & Hong, J. T. Berberine inhibits human neuroblastoma cell growth through induction of p53-dependent apoptosis. Anticancer Res. 28, 3777-3784 (2008).
2 Ermis, K., Midilli, A., Dincer, I. & Rosen, M. Artificial neural network analysis of world green energy use. Energy Policy 35, 1731-1743 (2007).
3 Midilli, A., Dincer, I. & Ay, M. Green energy strategies for sustainable development. Energy Policy 34, 3623-3633 (2006).
4 Midilli, A., Ay, M., Dincer, I. & Rosen, M. On hydrogen and hydrogen energy strategies: I: current status and needs. Renewable and sustainable energy reviews 9, 255-271 (2005).

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