【作者】 黄晓俊；

【导师】 A.P.Baker；

【作者基本信息】 哈尔滨工业大学 ， 材料物理与化学， 2010， 硕士

【摘要】 二氧化锡由于其具有敏感性高，响应时间短以及消耗低等优点，一直是作为制备半导体式金属氧化物气体传感器的广普材料。气体传感器的气敏特性受到很多因素的影响，诸如晶粒尺寸，多孔性，织构，小平面，晶粒间的连接方式等等。对制备参数，结构，形态和气敏特性之间的关系进行研究就显得尤为重要。在本文中，以结晶四氯化锡和乙二醇为前驱体，采用溶胶凝胶法成功地制备了纳米级别的二氧化锡涂层。在二氧化锡涂层制备过程中，前驱体之间的反应过程我们用傅里叶红外光谱仪进行了表征。与采用金属醇盐作为前驱体和水溶液做为溶剂相比，不仅价格便宜，而且溶胶稳定性也较好，即使是在高浓度的溶胶溶液中，凝胶化过程也不易受氯离子的影响。用热重—差热和傅里叶红外光谱仪对干凝胶的结晶过程进行了表征。结晶开始于179℃，有机物开始分解，到430℃的时候结晶完成。用X射线衍射光谱仪，拉曼光谱仪和扫描电镜对二氧化锡涂层的结构和形态进行了表征。用超声波喷雾高温分解法成功制备了小孔直径为30~50纳米的多孔小球，用溶胶凝胶旋涂法制备了纳米级别尺寸且具有良好分散性的二氧化锡涂层。用半导体参数仪测试了不同浓度下电阻的变化规律，不同涂敷次数下电阻率的变化规律，以及二氧化锡涂层电阻的热稳定性。以乙醇和丙酮做为测试气体，采用气敏测试系统对浓度为0.4mol/l，凃敷次数为6次，在600℃烧结制备得的样品进行了气敏性能测试。结果表明，制备得的涂层对乙醇有较好的敏感性和选择性。且对于测试的不同气体，存在一个最优的加热电压值，对于乙醇和丙酮分别是4.5V和5.0V.更多还原

【Abstract】 Tin dioxide (SnO2), is a suitable material for gas sensors application because ofits low cost, high sensitivity and fast response. The characteristics of the gas sensors areinfluenced by many factors, such as grain size, porosity, texture, faceting, grain network,etc. There are important factors for improving gas-sensing characteristics of tin dioxideresistive (conducto-metric) type sensors. So optimizing the preparation parameters andresearch on the relationships between the preparation parameters, micro-structure,morphology and sensitive properties are essential for the application of tin dioxide.In this dissertation, a sol-gel process starting with the tin tetrachloride andethylene glycol as precursors is successfully used to prepare nano-structured tin dioxidecoatings. The molecular structure evolution during the process has been identified usingFourier Transform infrared spectroscopy (FTIR). Compared to a sol-gel process usingmetal alkoxides or water“route”as precursors, this process is not only cost-effective butalso simple to control; the sol solution is extremely stable even in the presence of highconcentration of hydrochloride and the kinetics of the gelation process is not susceptibleto chloride ions. Further, conversions of xerogel to tin dioxide are studied using ThermoGravimetric Analysis-Differential Scanning Calorimeter (TG-DSC) and FTIR. It isfound that tin dioxide begins to form at a temperature as low as 179℃when organicsbegin to burn off. However, the tin dioxide coatings are formed only after the completecrystallization at about 430℃. As shown by X-Ray Diffraction (XRD), tin dioxidecoatings are prepared using ultrasonic spray pyrolysis and spin coating technology, themicro-structure and morphology are characterized by XRD, Raman Spectroscopy (RS)and Scanning Electron Microscopy (SEM). Porous tin dioxide coatings, made up ofballs (300~500nm in diameter) with 30~50nm micro-pores are successfully prepared.The resistance changes with concentration, the resistivity changes with coatingnumbers and the thermal stability of the resistance about the tin dioxide coatings underdifferent operation temperature are characterized by LCR meters (E4980A, Aglient). The optimum preparation parameters for lowest resistance and uniform tin dioxidecoatings are obtained. The sensor properties are measured by WS-60A test system withethanol and acetone as the target gases. There is an optimum heating voltage for ethanoland acetone, 4.5V and 5.0V respectively, and for the coating prepared, there is a bettersensitivity and selectivity for ethanol with the heating voltage in the range from 4.0 to4.75V.更多还原