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  本文關(guān)鍵詞： 碳納米管陣列 催化活性 球形碳 螺旋碳纖維 陷光　出處：《燕山大學》2016年碩士論文　論文類型：學位論文

【摘要】：本文利用熱化學氣相沉積(TCVD)的方法在單晶硅襯底上,以鎳為催化劑,通過碳源乙炔裂解制備了碳納米管陣列(CNTs)薄膜。分別使用掃描電子顯微鏡(SEM)和透射電子顯微鏡(TEM)表征了CNTs的形貌;并討論了催化劑、碳源氣體流量、生長時間等因素對CNTs生長的影響;分析了它們的形成機制;最后對碳納米管陣列的陷光性能進行了初步研究。實驗中鎳催化劑采用旋涂轉(zhuǎn)移和磁控濺射兩種方法制備。SEM結(jié)果表明利用單層聚苯乙烯(PS)微球,通過旋涂轉(zhuǎn)移法在硅襯底上制備的鎳催化劑具有規(guī)則的圖案化形貌,磁控濺射法制備鎳催化劑均勻且厚度可控。在生長定向CNTs時,催化劑厚度為5-10nm左右較為合適,催化劑厚度增加不利于CNTs的生長,是由于較厚的催化劑在高溫時容易發(fā)生團聚,會導致催化劑失去催化活性。同時研究了碳源氣體流量和生長時間對制備的CNTs影響,隨著碳源氣體流量的變大和生長時間的延長,制備的CNTs會發(fā)生管徑變粗、高度增加的現(xiàn)象,但是生長時間超過20min后,碳納米管高度不再繼續(xù)增加,當碳源乙炔氣體流量超過70sccm時,會導致實驗制備不出碳納米管。實驗對于單溫區(qū)不同位置碳源乙炔的裂解進行了研究,發(fā)現(xiàn)有溫度梯度存在的情況下,高溫管式爐中不同位置可以得到不同形貌的碳納米管陣列和球形碳,分析了碳納米管陣列和球形碳的形成機制以及形成差異的原因。使用鎳/銅網(wǎng)、Ni(NO3)2/Cu(NO3)2和Ni(NO3)2/Fe(NO3)3三種不同的復合催化劑來催化裂解碳源乙炔,制備出了不同形貌的螺旋狀碳纖維,探討了螺旋結(jié)構(gòu)的生長機制,并分析了催化劑活性對制備的碳纖維螺旋度的影響。利用紫外-可見分光光度計研究了CNTs薄膜和傳統(tǒng)硅基太陽能電池表面結(jié)構(gòu)的陷光性能,發(fā)現(xiàn)CNTs薄膜在波長200-800nm范圍的紫外-可見光波段反射率僅為5%左右,其減反射性能明顯優(yōu)于單晶硅和多晶硅電池絨面結(jié)構(gòu)。
[Abstract]:In this paper, nickel was used as catalyst on monocrystalline silicon substrate by thermochemical vapor deposition (TCVD) method. Carbon nanotube arrays (CNTs) thin films were prepared by acetylene pyrolysis. The morphology of CNTs was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The influence of growth time on the growth of CNTs and the mechanism of their formation were analyzed. Finally, the trapping properties of carbon nanotube arrays were preliminarily studied. In the experiment, the nickel catalyst was prepared by spin-coating transfer and magnetron sputtering. The SEM results showed that the single-layer polystyrene (PS) microspheres were used. The nickel catalyst prepared on Si substrate by spin-coating transfer method has regular patterned morphology, and the thickness of Ni catalyst prepared by magnetron sputtering method is uniform and controllable. The thickness of the catalyst is about 5-10nm when the growth orientation is CNTs. The increase of catalyst thickness is not conducive to the growth of CNTs, because the thicker catalyst is easy to agglomerate at high temperature, which will lead to the loss of catalytic activity. The effects of carbon source gas flow rate and growth time on the preparation of CNTs are also studied. With the increase of carbon source gas flow rate and the increase of growth time, the diameter and height of the prepared CNTs will increase, but after the growth time is more than 20 minutes, the height of CNTs will not continue to increase. When the flow rate of acetylene gas from carbon source exceeds 70 SCM, the carbon nanotubes can not be prepared experimentally. The pyrolysis of acetylene at different positions in the single temperature region is studied, and it is found that there exists a temperature gradient in the pyrolysis of acetylene. Carbon nanotube arrays and spherical carbon with different morphologies can be obtained in high temperature tube furnaces at different locations. The formation mechanism of carbon nanotube arrays and spherical carbon and the reasons for the difference in formation were analyzed. Three different kinds of composite catalysts, nickel / copper mesh nigno _ 3o _ 2 / cuno _ 3no _ 3O _ 2 and Ni(NO3)2/Fe(NO3)3, were used to catalyze the cracking of acetylene, and the spiral carbon fibers with different morphologies were prepared. The growth mechanism of helical structure and the effect of catalyst activity on the helicity of carbon fiber were discussed. The trapping properties of CNTs thin films and the surface structures of traditional silicon based solar cells were studied by UV-Vis spectrophotometer. It is found that the reflectivity of CNTs thin films in the wavelength range of 200-800 nm is only about 5% in the UV-Vis band, and its antireflection performance is obviously superior to that of single crystal silicon and polycrystalline silicon cell suede structure.
【學位授予單位】：燕山大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：TB383.1

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本文編號：1534862