不同结构掺氮超纳米金刚石薄膜制备及电化学性能研究

发布时间：2018-04-26 01:23

本文选题：二乙胺 + N-UNCD　；参考：《西南科技大学》2017年硕士论文

【摘要】：掺氮超纳米金刚石(N-UNCD)薄膜不仅具备传统金刚石优异的物化性能,而且显现出纳米材料和N型半导体的一些特殊效应,应用前景广阔。N-UNCD的结构对其宏观性能影响巨大,深入研究不同结构膜材的制备技术和性能特点是进一步开发其应用的基础和前提。本文首次采用二乙胺同时作为氮掺杂源和反应碳源,通过MPCVD技术在单晶硅基衬底上制备不同微观结构的N-UNCD薄膜,利用场发射扫描电子显微镜(SEM)、X射线衍射(XRD)、激光Raman光谱等详细表征其微观形貌、晶体结构和物相组成;在此基础上采用电化学分析技术系统地研究所制备的N-UNCD薄膜的电化学反应活性、双电层电容及阻抗等性能,并以多巴胺(DA)、抗坏血酸(AA)、金属铜离子(Cu2+)为研究对象考察N-UNCD薄膜的电化学检测能力。结果表明:(1)以二乙胺为唯一反应源可以制备出典型的N-UNCD薄膜,且随着二乙胺载入量的增加,N-UNCD薄膜的表面形貌从典型的等轴晶粒聚集状向超纳米金刚石晶粒/垂直石墨烯纳米墙复合结构演变,同时薄膜中结晶石墨相含量明显增加,导电性显著增强。(2)N-UNCD薄膜具有优于大多数碳材料的基本电化学性能,同时不同结构特性的N-UNCD的基本电化学特性也存在一定的差异。当N-UNCD薄膜呈现晶粒聚集状且石墨相含量较低时,通过[Fe(CN)6]3-/4-为氧化还原探针考察电化学活性,氧化峰与还原峰峰位差ΔEp值为119mV,随着薄膜中石墨相含量增加,表面逐渐变为金刚石/垂直石墨墙结构时,ΔEp减小到75 mV,且氧化峰电流强度逐渐增大;而薄膜双电层电容值则由42.1μF/cm2增加到337.6μF/cm2,同时石墨相含量高的N-UNCD薄膜在10000次充放电测试后,电容值仅下降10.3%;阻抗拟合结果显示电荷转移电阻由2486?减小到10.17?,双电层电容值增大。(3)N-UNCD薄膜对有机分子和金属离子具有良好的电化学检测能力。较低石墨相含量的薄膜检测DA,检测限为8.8μM,随着薄膜中石墨相增多,检测限降为0.4μM,还原峰峰电位由+0.35V向+0.175V偏移,线性相关度均在0.99以上;在检测AA时,随膜材结构改变检测限由12.95μM减小到4.4μM,但线性相关度也在0.99以上;检测Cu2+时,石墨相含量较少的薄膜具有更低的检测限,为0.12ppb,随着薄膜中石墨相增多,检测限增大为3.08ppb,线性相关度0.99降为0.98。(4)N-UNCD薄膜电化学性能随膜材结构变化而存在较大的差异,特定组成结构的N-UNCD薄膜电化学性能优异,是一种极具应用潜力的电化学储能和检测材料。
[Abstract]:Nitrogen-doped ultrananocrystalline diamond (N-UNCD) thin films not only possess excellent physical and chemical properties of traditional diamond, but also exhibit some special effects of nanomaterials and N-type semiconductors. The structure of N-UNCD has great influence on its macroscopical properties. It is the foundation and prerequisite to further develop the preparation technology and properties of different structure membrane materials. In this paper, diethylamine was used as a nitrogen dopant source and a reactive carbon source for the first time. N-UNCD thin films with different microstructure were prepared on monocrystalline silicon substrates by MPCVD technique. The microstructure, crystal structure and phase composition were characterized by field emission scanning electron microscopy (SEM) and X-ray diffraction (XRD), laser Raman spectroscopy, etc. On the basis of this, the electrochemical reaction activity, double layer capacitance and impedance of N-UNCD thin films prepared by electrochemical analysis were systematically studied. The electrochemical detection ability of N-UNCD thin films was investigated with dopamine (DA), ascorbic acid (AA) and copper ion (Cu2). The results show that the typical N-UNCD films can be prepared by using diethylamine as the sole reaction source. With the increase of loading amount of diethylamine, the surface morphology of N-UNCD film evolves from typical equiaxed grain aggregation to ultrananocrystalline / vertical graphene nanowall composite structure, and the content of crystalline graphite phase in the film increases obviously. The conductivity of N-UNCD thin films is significantly enhanced. The basic electrochemical properties of N-UNCD films are superior to those of most carbon materials. At the same time, the basic electrochemical properties of N-UNCD with different structure are also different. The electrochemical activity of N-UNCD thin films was investigated by [Fe(CN)6] 3 / 4- redox probe when the grain size was aggregated and the graphite phase content was low. The potential difference between the oxidation peak and the reduction peak 螖 E p was 119mV, with the increase of graphite phase content in the film. When the surface becomes diamond / vertical graphite wall structure, 螖 EP decreases to 75 MV, and the current intensity of oxidation peak increases gradually, while the capacitance of double layer increases from 42.1 渭 F/cm2 to 337.6 渭 F / cm 2. At the same time, the N-UNCD film with high graphite phase content increases after 10000 charge-discharge tests. The capacitance value decreased only by 10.3 and the impedance fitting results showed that the charge transfer resistance changed from 2486? When reduced to 10.17 渭 m, the double layer capacitance increases. The thin film has good electrochemical detection ability for organic molecules and metal ions. The detection limit of the thin film with lower graphite phase content is 8.8 渭 m. With the increase of graphite phase in the film, the detection limit decreases to 0.4 渭 M, the peak potential shifts from 0.35V to 0.175V, and the linear correlation is above 0.99. The detection limit decreased from 12.95 渭 M to 4.4 渭 M with the change of membrane structure, but the linear correlation was more than 0.99. In the detection of Cu2, the film with less graphite phase had a lower detection limit of 0.12 ppb, with the increase of graphite phase in the film. The detection limit is increased to 3.08 ppb, and the linear correlation is reduced to 0.99. The electrochemical properties of 0.98.(4)N-UNCD films vary with the structure of the films. The electrochemical properties of N-UNCD films with specific composition are excellent. It is a potential electrochemical energy storage and detection material.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ163;TB383.2

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