掺硼金刚石薄膜的制备及电化学性能研究

发布时间：2018-01-13 18:13

本文关键词：掺硼金刚石薄膜的制备及电化学性能研究　出处：《天津理工大学》2013年硕士论文　论文类型：学位论文

【摘要】：目前，化学气相沉积（CVD）硼掺杂金刚石具有良好的物理、化学特性，这使其非常适合作为新型电极材料。硼掺杂金刚石(BDD)既具有金刚石极高的硬度和化学稳定性的特性，还具有良好的导电性、低背景电流、宽电势窗口等优点。因此BDD电极的性能优于传统的玻碳、石墨及其他形式的电极，在电化学检测、合成、分解等领域具有广阔的应用前景。针对目前硼掺杂金刚石薄膜的不同CVD制备特点和优缺点，本文在热丝、直流电弧等离子体喷射掺硼金刚石薄膜（BDD）的工艺研究、BDD电极的基本电化学性能研究及应用检测多巴胺等方面开展了如下工作：（1）热丝化学气相沉积法（hot filament chemical vapor deposition，HFCVD）制备金刚石薄膜。通过研究灯丝碳化条件解决了灯丝熔断问题，进一步研究形核和生长参数（温度、气压、时间），得到纳米级别金刚石晶粒，其单一性好，C-C以sp~3结合为主。缺点是灯丝的挥发易引入污染，不利于研究掺杂金刚石薄膜的导电性能研究。（2）利用直流电弧等离子喷射（DC arc plasma jet CVD）制备硼掺杂金刚石薄膜，采用特制石墨基台控制基台的温度平衡，从而控制硅衬底的温度；通过控制条件（压强、气体比例等）得到单一性较好的(100)和（111）晶向硅基金刚石薄膜，且生长速率高。此外又进行硼的掺杂（原位掺杂），，制得的掺硼金刚石薄膜在保持金刚石性能同时，可达到0.009·cm的电导率。本文首次利用该方法制备出了重硼掺杂金刚石薄膜。（3）制得BDD电极，不经任何修饰，将其作为电化学工作站阳极，在硫酸钠空白溶液及铁氰化钾/亚铁氰化钾混合液中循环伏安扫描，电极的电化学窗户达到4V（-2V~2V），表现出很高的反应速率和电化学稳定性能，电极表面不易被污染。（4）将L-半胱氨酸电聚合修饰到该BDD电极表面，研究了多巴胺在该修饰电极上的电化学性能。改变扫描速率使多巴胺在电极上的氧化还原反应得到最佳响应，探测不同浓度（以10为数量级）的多巴胺中在该电极上的响应，得到检测限度为1×10~(-11)mol/L，经过分析在1×10~(-9)~1×10~(-6)mol/L范围内，多巴胺溶液的浓度对数与氧化峰电流成线性关系，该结论在实际任意浓度的测量中得到了验证。在高浓度抗坏血酸共存下，BDD对于多巴胺的检测不受影响，实验验证了随机浓度的多巴胺浓度，理论与实际的偏差小于6%，具有一定的使用价值。
[Abstract]:At present, chemical vapor deposition (CVD) boron doped diamond has good physical and chemical properties. Boron doped diamond BDDs not only have high hardness and chemical stability of diamond, but also have good electrical conductivity and low background current. Therefore, the performance of BDD electrode is superior to that of traditional glassy carbon, graphite and other kinds of electrodes. It has a broad application prospect in electrochemical detection, synthesis, decomposition and other fields. According to the characteristics, advantages and disadvantages of different boron doped diamond films prepared by CVD, this paper studies the technology of hot filament, DC arc plasma jet boron doped diamond film BDDs. The basic electrochemical performance of BDD electrode and its application in the detection of dopamine have been studied as follows: 1) hot filament chemical vapor deposition. Diamond films were prepared by HFCVD. The melting problem of filament was solved by studying the carbonization conditions of filament. The nucleation and growth parameters (temperature, pressure, time) were further studied, and nanocrystalline diamond grains were obtained. The singularity of C-C is mainly composed of sp~3. The disadvantage is that the volatilization of filament is easy to lead into pollution, which is not conducive to the study of conductive properties of doped diamond films. B doped diamond films were prepared by DC arc plasma jet DC arc plasma jet CVD. The temperature balance of the substrate was controlled by a special graphite base platform. Thus, the temperature of silicon substrate is controlled; By controlling the conditions (pressure, gas ratio, etc.), the diamond films with good singularity and crystal orientation were obtained, and the growth rate was high. In addition, boron doping (in situ doping) was carried out. The obtained boron doped diamond films can achieve a conductivity of 0.009 路cm while maintaining the diamond properties. In this paper, the heavily boron doped diamond films have been prepared by this method for the first time. BDD electrode was prepared and used as anode for electrochemical workstation without any modification. The electrode was scanned by cyclic voltammetry in sodium sulfate blank solution and potassium ferricyanide / potassium ferricyanide mixture solution. The electrochemical window of the electrode reaches 4V ~ 2V ~ (2) V ~ (-1), showing high reaction rate and electrochemical stability, and the electrode surface is not easy to be contaminated. L- cysteine was electropolymerized onto the surface of the BDD electrode. The electrochemical performance of dopamine on the modified electrode was studied. The redox reaction of dopamine on the electrode was optimized by changing the scanning rate. The response of dopamine at different concentrations (10 orders of magnitude) to the electrode was detected, and the detection limit was 1 脳 10 ~ (-1) -11 mol / L. The linear relationship between the concentration logarithm of dopamine solution and the oxidation peak current was analyzed in the range of 1 脳 10 ~ (-1) ~ (-9) ~ (-1) mol / L ~ (-1 脳 10 ~ (-1)) ~ (-1) ~ (-1) mol / L. This conclusion has been verified in the actual measurement of any concentration of ascorbic acid. BDD has no effect on the detection of dopamine in the presence of high concentration of ascorbic acid, and the random concentration of dopamine has been verified by the experiment. The deviation between theory and practice is less than 6.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：O484.1

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