【作者】 蒋忠伟；

【导师】 李民强；

【作者基本信息】 中国科学技术大学 ， 无机化学， 2010， 硕士

【摘要】 金属氧化物半导体传感器作为当今科技前沿热点之一,仍然面临着诸多亟待解决的问题,提高传感器性能依然是我们所追求的研究目标。近年来,通过对传统的传感材料进行掺杂、修饰处理和开发新型传感材料,为传感器研究提供了新的发展动力。基于此,本论文探索对传统的SnO2薄膜材料进行稀土元素掺杂以及制备具有多孔结构的大孔SnO2薄膜材料,并详细地考察薄膜材料的气敏性质,以获得高性能的传感器。此外,合成了一种形貌新颖的Au修饰的茧型-La2O3纳米材料并发现该材料具有良好的催化发光性质。本论文的主要内容如下:一.采用简单的和低成本的溶胶凝胶方法和薄膜蘸涂工艺制备了掺杂稀土元素Ce的SnO2敏感薄膜,系统地研究了薄膜传感器的工作温度、掺杂量、煅烧温度、薄膜层数以及环境湿度对传感器检测丁酮的影响。研究发现,当工作温度为210℃、Ce的掺杂量为1 at%、煅烧温度为500℃、薄膜层数为4层时,在干燥空气中该Ce-SnO2薄膜传感器对100 ppm丁酮存在最高响应灵敏度为181。此外,通过掺杂稀土元素Ce可以有效的降低SnO2薄膜传感器的工作温度,提高响应灵敏度和改善选择性。结果表明,该薄膜传感器对丁酮有良好的气敏性质,在安检系统和环境监测领域具有潜在的应用前景。二.以碳质纳米粒子为模板,成功地合成了具有多孔结构的大孔SnO2薄膜传感器。该大孔SnO2薄膜由较致密的大孔和纳米孔结构组成,具有较大的比表面积和和较小的晶粒尺寸。气敏性研究表明:该大孔SnO2薄膜传感器对乙醇、丙酮、四氢呋喃和丁酮等有机挥发性气体表现出良好的气敏响应特性。此外,该传感器具有一定的选择性和较低的检测限、迅速的响应和恢复时间。三.通过简单的水热法,制备了由纳米线缠绕组成的茧形-La(OH)3前躯体,并初步探讨了实验过程中影响产物形貌的反应条件:反应温度、反应时间、反应物浓度及配比等因素。运用紫外光辐射法修饰茧形-La(OH)3纳米材料并进行高温煅烧,得到了Au修饰的茧形-La2O3纳米材料。将其用于构筑催化发光传感器研究发现,该传感器具有很好的催化发光强度和信噪比。对比未修饰的茧形-La2O3纳米材料,Au修饰后的材料对四氢呋喃、丙酮、丁酮和乙醇等四种待测物的催化发光强度得到大大增强。而且,对苯、氯仿和氯苯等也有很好的响应强度,该材料在检测挥发性有机化合物和持久性有机污染物上具有很好的应用前景。更多还原

【Abstract】 As a research focus of science and technology, metal-oxide semiconductor sensors have been investigated several dozens years. However, improving gas-sensing properties has been a pursing goal. Recently, doped or functional of conventional sensing materials or synthesized new-style sensing materials have provided new power for the development of sensors.Herein, Ce-doped SnO2 thin films and macroporous SnO₂ thin films have been prepared. In order to obtained high-performance sensors, the gas-sensing properties of SnO₂ thin film were investigated in detail. Moreover, one kind of novelty morphology Au modified cocoon-like La2O3 sensing nanomaterials were synthesized and applied in cataluminescence sensor for the detection of volatile organic compounds. The main contents are summarized as follows:1. Different concentrations of Ce-doped SnO₂ thin films were fabricated via the sol-gel method and dip-coating technique. Furthermore, the influencing factors of gas-sensing properties for butanone, such as cerium concentration, calcination temperature, the layers of thin films and humidity, were investigated. The results indicated that four-layer 1 at% Ce-doped SnO2 thin films calcined at 500 ?C presented the best response to butanone. At the optimal working temperature of 210 ?C, the response to 100ppm of butanone vapor was about 181 in dry air. The gas-sensing results showed that the approach of doping cerium had greatly improved the gas-sensing response and decreased the working temperature. Most importantly, the gas sensor presented selective response to butanone among all investigated gases. Accordingly, the gas sensors based on 1 at% Ce-doped SnO2 thin films have a promising application for the detection of butanone in practical security inspection environment.2. Macroporous SnO₂ thin films sensor was prepared using carbonaceous nanospheres as templates and sol-gel method. The thin films were made up of compact macroporous and nanoporous structure with lager specific surface area. The gas-sensing properties result showed that macroporous SnO2 thin films exhibited better response to ethanol, acetone, tetrahydrofuran and butanone, compared with common SnO2 thin films. Moreover, the gas sensor showed good selectivity, low detection limit, short response and recovery times. 3. One kind of novelty morphology cocoon-like La（OH）₃ precursor enlaced by nanowires were prepared by a simple hydrothermal method using oxalic acid as soft template. The influencing factors of morphology were researched, such as reaction temperature, reaction time, the molar of NaOH and oxalic acid. After modified by gold nanoparticles using ultraviolet irradiation method and calcined, the Au/La2O3 nanomaterials which exhibited good cataluminescence signals were obtained. For the detection of volatile organic compounds, such as acetone, tetrahydrofuran, ethanol, butanone, benzene, chloroform, chlorobenzene, the Au/La2O3 cataluminescence sensor showed stronger intensity compared with pure La2O3 nanomaterials. Accordingly, the gas sensors based on cocoon-like Au/La2O3 nanomaterials have a promising application for the detection of volatile organic compounds and persistent organic pollutants in environmental protection.更多还原