金属掺杂对二氧化锡纳米结构和气敏性能的影响

发布时间：2018-03-18 23:37

本文选题：二氧化锡　切入点：异质结　出处：《西北师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：二氧化锡是一种重要的n型直接带隙宽禁带氧化物半导体,室温下直接带隙宽度为3.6 eV,激子束缚能高达130 meV。因其纳米材料具有独特的电学、光学和化学性质,在太阳能电池、激光二极管、紫外激光器、表面声波器、压电传感器和气敏传感器等方面有重要运用价值。但是,系统的研究其形貌对不同气体的气敏响应仍然缺乏研究。因此,我们可以进一步通过生长参数的优化,如掺杂、表面修饰、与半导体或者金属复合等方式对SnO_2纳米材料进行形貌改性。本实验主要以静电纺丝法制备零维纳米粒子、一维纳米管及使用水热法制备多孔分层的三维纳米花为思路基础,控制制备了小尺寸(直径小于10 nm)的球形SnO_2纳米颗粒、Y掺杂的SnO_2纳米管、TiO2-SnO_2复合纳米管和三维多孔的SnO_2纳米花等功能性纳米材料,并分别对其气敏特性进行了研究。主要述及以下几方面的研究工作:1.利用静电纺丝技术和退火炉相结合成功的制备了珊瑚状多孔的Y掺杂球形SnO_2零维纳米颗粒。并对所有样品进行了形貌和结构的表征,结果发现5 wt%Y掺杂SnO_2纳米结构有较小的粒径尺寸和较大的比表面积。此外,通过气体敏感测试发现,5 wt%Y掺杂SnO_2纳米结构基传感器在300°C下对冰乙酸具有较高的响应值、短的响应恢复时间及好的选择性。并且,通过对结构和形貌的分析,本实验研究了其气敏机理,结果发现,Y掺杂的SnO_2纳米结构基传感器响应的提高主要归结于掺杂导致的颗粒尺寸减小引起的小尺寸效应和多孔的表面结构的形成。因此,这种珊瑚状多孔的Y掺杂SnO_2纳米结构可以作为一种潜在的冰乙酸传感器材料。2.通过静电纺丝法和管式退火炉相结合制备了纯的和Y掺杂的SnO_2一维纳米管结构,并对所得样品进行了形貌和结构的表征,测试了所有样品对丙酮气体的气敏响应情况。结果发现,Y掺杂的SnO_2纳米管相较于纯的SnO_2纳米管有更大的比表面积。并且组成SnO_2纳米管的晶粒尺寸对纯的和Y掺杂的分别为21.8 nm和20 nm,同时经过XPS测试发现,Y3+替代Sn4+成功的掺进了SnO_2纳米结构中。此外,由于制备的SnO_2纳米管具有优异的多孔结构,通过气体敏感测试发现,相较于纯的,Y掺杂的SnO_2基传感器对丙酮具有更高的响应值、短的响应恢复时间、较好的选择性和长时间的稳定性。根据结构和形貌分析,本实验对SnO_2纳米管结构的形成机制以及其气敏机理进行了探讨。最终,我们发现稀土元素Y的引入对SnO_2纳米管丙酮气敏性能的检测有显著的改善。3.我们在前一章的研究基础上用静电纺丝的方法制备了复合TiO2-SnO_2异质结构的纳米管,对所有样品进行了形貌和结构的表征,发现构成复合纳米管的纳米颗粒直径在12 nm左右,其比表面积远大于上一章制备的Y修饰的SnO_2纳米管。并进一步测试了所有样品对丙酮气体的气敏响应情况。结果显示,用静电纺丝法制备的复合TiO2-SnO_2异质结构的纳米管相较与Y修饰的SnO_2纳米管的直径增大了,且表面更加粗糙。气敏测试结果显示,复合TiO2-SnO_2异质结构的纳米管气敏性能相较与Y修饰的SnO_2纳米管有显著的改善。其主要原因就是我们构建了异质结构导致吸附氧和载流电子之间的表面反应增强所引起的。我们知道改善气敏材料的气敏性能主要通过下面两个方面:(1)通过减小晶粒尺寸增加传感器材料的表面活性区域,构建多孔材料(空心、介孔材料等)来增加互动表面提供更多的活性位点。(2)通过稀土元素以及贵金属等的修饰来改变半导体的本征电学特性,来增加材料的表面载流子浓度以及对材料形貌的优化。本实验通过这两方面的改善,制备出了复合TiO2-SnO_2异质结构的纳米管,相较于前一章对丙酮的气敏性能有了大的提升。4.利用水热法制备了三维多孔的SnO_2纳米花,通过XRD、SEM、TEM等表征技术对SnO_2纳米花的微观结构进行表征,结果发现SnO_2纳米花有良好的结晶度,花瓣的厚度在20 nm左右,并且由很多的孔洞构成的纳米片组成。对形成的多孔的纳米花涂覆在带电极的陶瓷管上制成纳米花基传感器,通过气敏测试发现SnO_2纳米花有良好的丙酮气敏性,与之前的结果相比较,敏感性能得到了进一步的提高。
[Abstract]:Two tin oxide is a direct wide bandgap semiconductor oxide is an important n type at room temperature, direct band gap width of 3.6 eV and a high exciton binding energy of 130 meV. nano materials because of its unique electrical, optical and chemical properties of laser diode in solar cell, UV laser, surface acoustic wave device. Has an important application value of piezoelectric sensor and gas sensor and so on. However, systematic research on gas sensing response of the morphology of different gases are still lack of study. Therefore, we can further optimize the growth parameters such as doping, surface modification, and semiconductor or metal compound on SnO_2 nano material morphology was modified. This experiment mainly by electrospinning of zero dimensional nanoparticles, one-dimensional nanotubes and 3D nano porous layer using hydrothermal method for the idea of flower foundation, were prepared by controlling the small size (small diameter In 10, NM) of spherical SnO_2 nanoparticles, Y doped SnO_2 nanotubes, SnO_2 nano flowers and other functional nano materials and porous TiO2-SnO_2 composite nanotubes, and the gas sensing properties were studied. The main research work in the following aspects: 1. using electrospinning and annealing furnace combined successfully the preparation of Y doped SnO_2 porous coral by zero dimensional nanoparticles. And all the samples were characterized by morphology and structure, the results showed that 5 wt%Y doped SnO_2 nano structure has smaller particle size and larger surface area. In addition, the gas sensitive test found that the response to the 5 wt%Y doped SnO_2 nano sensor has high on acetic acid at 300 ~ C value, short response time and recovery time and good selectivity. And through the analysis on the structure and morphology, this experiment studied the gas sensing mechanism, found The formation of surface structure, particle size of Y doped SnO_2 nano sensor response increase is mainly due to the doping decrease the effect of the small size and the porous. Therefore, Y doped SnO_2 nano porous structure of the coral can be used as a potential ice acetic acid sensor material.2. by electrospinning method and tube SnO_2 type annealing furnace combining one-dimensional nanotube structure of pure and doped Y were prepared, and the samples were used to characterize the morphology and structure of all the samples, gas sensing response to acetone gas was tested. The results showed that the Y doped SnO_2 nanotubes compared to pure SnO_2 nanotubes have higher surface area. Grain size and the composition of SnO_2 nanotubes on pure and doped Y were 21.8 nm and 20 nm, and after XPS test found that the substitution of Y3+ Sn4+ successfully doped into the SnO_2 nano structure. In addition, The preparation of SnO_2 nanotubes have excellent porous structure, through the gas sensitive test showed that, compared to the pure and SnO_2 doped Y based sensor has higher response value of acetone, short response time, good selectivity and stability of long time. According to the structure and morphology analysis, the experiments were carried out to investigate the formation mechanism of SnO_2 nanotubes and their gas sensing mechanism. Finally, we found that the introduction of rare earth element Y detection of SnO_2 nanotubes acetone gas sensing properties of.3. were improved significantly in our basic research on the previous chapter by electrospinning composite TiO2-SnO_2 heterostructure nanotube were prepared for all samples the characterization of morphology and structure, a nano particle composite nanotubes with a diameter of about 12 nm, the specific surface area is much larger than the previous chapter Y modified preparation of SnO_2 nanotubes and one. Step test all the sample gas sensing response to acetone gas. The results show that the composite TiO2-SnO_2 heterostructures prepared by electrospinning the nanotubes compared with Y modified SnO_2 nanotube diameter increases, and the surface is more rough. The gas sensing test results show that the gas sensing properties of TiO2-SnO_2 composite nanotube heterostructures compared with Y the modified SnO_2 nanotubes is significantly improved. The main reason is that we construct the heterogeneous structure leads to adsorbed oxygen and current carrying electrons between the surface reaction enhanced by it. We know that to improve gas sensing property of materials mainly through the following two aspects: (1) by increasing the surface area of the sensor active material grain size reduce construction of porous materials (hollow mesoporous materials) to increase the interaction surface provides more active sites. (2) modified by rare earth elements and precious metals etc. To change the electrical properties of semiconductor, to increase the carrier concentration of surface materials and optimization of the morphology of the materials. Through the experiments of the two aspects of the improvement of prepared composite TiO2-SnO_2 heterostructure nanotube, compared to the previous chapter, gas sensitivity to acetone has been a big upgrade of.4. by hydrothermal method SnO_2 nano porous flower, prepared by XRD, SEM, TEM and other characterization techniques on the microstructure of SnO_2 nano flowers were investigated, the results showed that SnO_2 nano flowers have good crystallinity, petal thickness around 20 nm, and consists of many nano holes composition on the formation of the porous nano. Flower is coated on the electroded tube made of ceramic nano flower base by sensor, gas sensitive test showed that SnO_2 nanoflower acetone gas sensitivity good, compared with the previous results, the sensitive performance has been further improved.

【学位授予单位】：西北师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ134.32;TB383.1

【相似文献】