【作者】 张波；

【导师】 张建新； 蔡伟；

【作者基本信息】 哈尔滨工业大学 ， 材料物理与化学， 2011， 博士

【摘要】 随着能源危机日益加重,具有节能减排应用的低辐射玻璃研究成为热点。其可以在保证建筑玻璃采光性能的前提下,反射掉大部分太阳光及室内热源发射出的红外线,阻止热量散失,降低建筑物能源消耗。目前应用的低辐射薄膜以金属银膜为主,其普遍存在薄膜机械性能较差、反射可见光、制备成本高等缺点。近年来,采用超声喷雾热解制备SnO₂薄膜克服了传统银膜的缺点,具有优异的光学性能和机械物理性能,但也存在反射率偏低和反射起始波长过大的问题,而且薄膜中结构缺陷对反射率的影响机制也尚不清楚。探索合理的SnO₂薄膜的喷雾热解制备工艺及进行SnO₂薄膜改性研究工作及是解决这些问题的关键。本文采用超声喷雾热解方法在玻璃基体上制备了SnO₂薄膜及氟、锑、硼和锂掺杂SnO₂薄膜,利用X射线衍射、红外光谱、分光光度计和霍尔效应等测试手段,系统研究了制备工艺和掺杂元素种类和浓度对薄膜的结构和光电性能的影响规律,揭示了掺杂离子在SnO₂晶格中的占位机制。超声喷雾热解方法制备SnO₂薄膜的沉积过程的研究表明,对于水性溶液,液滴的挥发速率和先析出固体壳层的渗透性决定了液滴的形成过程:液滴挥发速率大易形成空心球粒子,液滴挥发速率小易形成泡状结构;壳层渗透性好时,形成破碎空心球粒子,而壳层渗透性差时形成球形微粒。超声喷雾热解方法制备SnO₂薄膜的工艺研究表明,基体温度在350℃时,SnO₂薄膜均匀致密,表面光滑。基体温度过低和过高分别造成薄膜表面形成颗粒堆积和龟裂;薄膜厚度增加,电阻率下降,薄膜厚度大于1.1μm时,薄膜厚度对电学性能影响减小;当载气流量和雾化速率的比值为4:1时,薄膜均匀致密,光学性能优异;氟掺杂SnO₂薄膜的研究表明,当溶液中氟锡原子比小于0.75时,氟离子进入晶格中优先占据O-Sn-O基团中氧位造成O-Sn-O基团振动劈裂,形成FO′缺陷并释放出自由电子,导致薄膜中载流子浓度增大;当溶液中氟锡原子比大于0.75时,氟离子填充晶格间隙位置形成间隙氟,造成薄膜中载流子浓度降低。以SnCl₂和SnCl₄为锡前驱物制备的SnO₂:F薄膜的研究表明,氟掺杂的SnO₂薄膜中依然存在氧空位,掺杂浓度增加,氧空位浓度降低,氟离子置换氧离子造成的FO·缺陷逐渐成为载流子的施主;以氢氟酸和氟化铵为氟前驱体制备SnO₂:F薄膜时,氟掺杂浓度对氟离子在SnO₂晶格中固溶行为和光电性能的影响规律类似。氟等量掺杂时,以氢氟酸为氟前驱物制备的薄膜的反射率较低,说明氢氟酸活性较差。锑掺杂的SnO₂薄膜的研究表明,当溶液中锑锡原子比小于2.0%时,进入到SnO₂晶格中的锑离子取代锡离子并表现为+5价态,形成施主缺陷,从而造成薄膜的自由载流子浓度增大;当锑锡原子比大于2.0%时,锑离子以+3价态形式置换锡离子,造成O-Sn-O基团振动的劈裂并形成受主缺陷,导致薄膜的自由载流子浓度降低;硼掺杂的SnO₂薄膜的研究表明,当溶液中硼锡原子比较低时,硼离子易填充SnO₂晶格间隙处形成间隙硼（Bi′′′）,薄膜中载流子浓度上升,但当硼锡原子比为4.0%时,在晶格中造成大量缺陷,使薄膜的光电性能下降;锂掺杂的SnO₂薄膜的研究表明,锂离子取代晶格中锡位置造成薄膜中载流子浓度降低,薄膜的光反射特性消失。更多还原

【Abstract】 With the increased situation of Energy Crisis, the low-emssion glass, which can save energy and reduce pollution, becomes one of hot topics in research. The low-emission glass can reflect infrared ray emmitted from sunshine and body indoor, without the losing the transittance in visible. It can prevent the heat exchange between both sides of glass and decrease the buliding energy comsumption. However, the current low-emission glass is composed by Ag films, which has high cost, high reflectance in visible. The SnO₂ films prepared by ultrasonic spray pyrolysis can overcome the disadvantages of the Ag films. There are also some problems in low emission film of SnO₂, such as weak reflectivity in near infrared, high cutoff wavelength of infrared reflectivity etc. Moreove, the mechanism of refectivity in SnO₂ films and the releation betweent the film structure and optical-electrical properties needs more research work. The probe into the preparation parameters and the modified SnO₂ films may be the key point of the research work. In the paper, we investigated the proper preparation parametes in ultrasonic spray pyrolysis and the releation betweent the structure and optical-electrical properties in SnO₂ films. The fluorine doped SnO₂ film, boron doped SnO₂ films and lithium doped SnO₂ films also have been studied.The preparation parameters showed that droplet flux and carrier gas flux decided the deposition process; drying rate and permeabitiy affected the transformaiton of particles; the effect of thickness on the electrical properties was not obvious when the thickness was more than1.1μm; the temperature of 350℃was suitable for deposition.The results of fluorine doped SnO₂ films showed that, at low fluorine doping levels, the fluorine ions substituted the oxide ions in SnO₂ lattice to form the defect of FO·and release the electrons, that in turn, leading to the splitting of O-Sn-O vibration and increasing of carrier concentration in films; at high fluorine doping levels, fluorine ions became to fill the intersitital site, forming the defect of Fi′, which could decrease the carrier concentration in films and move the vibration frequency of Sn-O. The optical reflectivity showed the similar rule with carrier concentration at different doping levels, which could be explained by Drude theory. The main scattering mechanism in SnO₂:F films is the impurity ions scattering.The results of SnO₂ films prepared from SnCl₂ and SnCl₄ showed the oxygen vacancy existed in fluorine doped SnO₂ films. With the increased fluorine concentrations, the contribution of oxygen vacancy became weak; the results of SnO₂ films prepared from NH4F and HF showed the activity of HF was not as good as NH4F at the same fluorine doping level.The results of SnO₂:Sb films showed that when antimony doping concentration was less than 2.0%, the antimony ions in SnO₂ lattice behaved +5 valence state and substituted tin ions forming the donor defect and increase of carrier concentration; when antimony concentration was more than 2.0%, the antimony showed +3 valence state and substituted tin ions forming acceptor defect and decrease of carrier concentration, which had a negetive effect on the reflectivity of SnO₂:Sb films. The results of SnO₂:B films showed that a small quantitiy of bonor ions in SnO₂ lattice would fill the intersitital site to form Bi′′′and increase the carrier concentration and reflectivity; too much bonor ions in SnO₂ lattice could make bonor ions to substitute tin ions and decrease the reflectivity and carrier concentration. The results of SnO₂:Li films showed lithium ions in SnO₂ lattice would substitute the tin ions, that in turn to the disappear of optical reflectivity and electrical properties.更多还原