银纳米线的制备及其在智能玻璃中的应用
发布时间：2018-08-13 09:31
【摘要】：银纳米线(AgNWs)具有比表面积大、反应活性高、导电性好等特点,在光学、电学、生物学等领域有良好的应用前景,近年来备受研究者关注。制备银纳米线的报道较多,但是具有小直径和超高长径比的银纳米线的合成仍然是一个难题。智能玻璃是一种在电场的开关作用下分别显示透明和不透明两种状态的功能玻璃,由于其价格昂贵未能得到广泛的应用。制备具有超高长径比银纳米线,并将其用于透明电极和智能玻璃,具有重要的学术和应用价值,文献鲜有这方面的报道。本文研究了制备工艺参数对银纳米线形貌结构的影响,并采用SEM、XRD、UV-Vis等手段对其进行表征,进而研究了其在智能玻璃中的应用。首先,采用一步醇热还原法制备了高长径比且尺寸均匀的银纳米线,研究了制备工艺参数,如AgNO_3浓度、AgNO_3与PVP的配比、反应温度、成核控制剂用量、溶剂种类、PVP分子量等,对银纳米线的影响,并阐明了具体的影响机制。本文研究发现,AgNO_3的浓度及反应温度对五次孪晶晶核(MTP)的形成具有重要的影响,进而影响产物的均匀性。AgNO_3与PVP的配比较低时易于产生折线形状的银纳米线,其可能原因在于银纳米线端面形成新的孪晶晶核,继而生长出新的银纳米线。研究还发现,溶剂对银纳米线的生长影响巨大,分别采用乙二醇、1,5-戊二醇及1,3-丁二醇为溶剂制备了银纳米线,其形貌有显著差别,我们从反应速率角度阐述了原因。此外,相对于低分子量,使用分子量较高的PVP作为体系分散剂和生长方向诱导剂,可制得尺寸均匀、形貌较好的银纳米线。最后,通过选择适宜的混合溶剂体系及相关工艺参数,制备了形貌优异的银纳米线,平均长度为100μm,平均直径为70 nm,长径比高达1400。将不同规格的银纳米线涂覆在玻璃片上制备透明电极,测试方块电阻和可见光透过率,发现采用具有高长径比的银纳米线制得的透明电极的性能较好。将银纳米线透明电极在一定的温度下处理,发现在节点位置银纳米线存在融合现象,使得方块电阻明显下降,而透光率基本没有变化。最后,选择性能良好的透明电极制作成液晶盒,进而制作出智能玻璃。探讨了液晶含量、液晶膜厚度、光照强度等工艺参数对智能玻璃光电性能的影响。优化工艺,制得了阈值电压为20 V且在550 nm波长处透过率达到74%的智能玻璃样品。
[Abstract]:Silver nanowires (AgNWs) have many advantages such as large specific surface area, high reactive activity and good electrical conductivity. They have a good application prospect in optics, electricity, biology and so on, and have attracted much attention in recent years. There are many reports on the preparation of silver nanowires, but the synthesis of silver nanowires with small diameter and ultra-high aspect ratio is still a difficult problem. Smart glass is a kind of functional glass which displays transparent and opaque states under the action of electric field switch respectively. It is not widely used because of its high price. The preparation of silver nanowires with ultra-high aspect ratio and their use in transparent electrodes and smart glass has important academic and application value. In this paper, the influence of preparation parameters on the morphology and structure of silver nanowires was studied, and the structure of silver nanowires was characterized by means of SEMXRD- UV-Vis, and the application of silver nanowires in intelligent glass was studied. First, silver nanowires with high aspect ratio and uniform size were prepared by one-step alcohol thermal reduction method. The preparation parameters such as the ratio of AgNO_3 concentration and PVP, reaction temperature, amount of nucleation control agent, and molecular weight of AgNO_3 were studied. The effect on silver nanowires is discussed, and the mechanism of influence is explained. It is found that the concentration of Agno _ 3 and the reaction temperature have an important effect on the formation of (MTP) in the quintic twin nucleus, and then influence the homogeneity of the product. When the ratio of Agno _ 3 to PVP is low, silver nanowires with the shape of broken lines are easy to be produced. This may be due to the formation of new twin nuclei at the end of the silver nanowires and the subsequent growth of new silver nanowires. It was also found that the solvent had a great influence on the growth of silver nanowires. The silver nanowires were prepared by using ethylene glycol (EG) 1 / 5 pentanediol and (1) 3 (butanediol) respectively. The morphology of silver nanowires was significantly different, and the reason was explained from the point of reaction rate. In addition, compared with low molecular weight, silver nanowires with uniform size and good morphology can be prepared by using high molecular weight PVP as dispersant and growth direction inducer. Finally, silver nanowires with excellent morphology were prepared by selecting suitable mixed solvent system and related technological parameters. The average length of silver nanowires was 100 渭 m, the average diameter was 70 nm, and the aspect to diameter ratio was up to 1 400. The transparent electrode was prepared by coating silver nanowires with different specifications on glass. The results showed that the transparent electrode prepared by silver nanowires with high aspect ratio had good performance by measuring the square resistance and visible light transmittance. When the silver nanowire transparent electrode is treated at a certain temperature, it is found that the silver nanowires are fused at the node position, which makes the square resistance decrease obviously, but the transmittance is not changed. Finally, the transparent electrode with good performance is selected to make the liquid crystal cell, and then the intelligent glass is made. The effects of liquid crystal content, liquid crystal film thickness and illumination intensity on the optoelectronic properties of smart glass were discussed. An intelligent glass sample with a threshold voltage of 20 V and a transmittance of 74% at 550 nm wavelength was obtained.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;TQ171.1
本文编号：2180578
[Abstract]:Silver nanowires (AgNWs) have many advantages such as large specific surface area, high reactive activity and good electrical conductivity. They have a good application prospect in optics, electricity, biology and so on, and have attracted much attention in recent years. There are many reports on the preparation of silver nanowires, but the synthesis of silver nanowires with small diameter and ultra-high aspect ratio is still a difficult problem. Smart glass is a kind of functional glass which displays transparent and opaque states under the action of electric field switch respectively. It is not widely used because of its high price. The preparation of silver nanowires with ultra-high aspect ratio and their use in transparent electrodes and smart glass has important academic and application value. In this paper, the influence of preparation parameters on the morphology and structure of silver nanowires was studied, and the structure of silver nanowires was characterized by means of SEMXRD- UV-Vis, and the application of silver nanowires in intelligent glass was studied. First, silver nanowires with high aspect ratio and uniform size were prepared by one-step alcohol thermal reduction method. The preparation parameters such as the ratio of AgNO_3 concentration and PVP, reaction temperature, amount of nucleation control agent, and molecular weight of AgNO_3 were studied. The effect on silver nanowires is discussed, and the mechanism of influence is explained. It is found that the concentration of Agno _ 3 and the reaction temperature have an important effect on the formation of (MTP) in the quintic twin nucleus, and then influence the homogeneity of the product. When the ratio of Agno _ 3 to PVP is low, silver nanowires with the shape of broken lines are easy to be produced. This may be due to the formation of new twin nuclei at the end of the silver nanowires and the subsequent growth of new silver nanowires. It was also found that the solvent had a great influence on the growth of silver nanowires. The silver nanowires were prepared by using ethylene glycol (EG) 1 / 5 pentanediol and (1) 3 (butanediol) respectively. The morphology of silver nanowires was significantly different, and the reason was explained from the point of reaction rate. In addition, compared with low molecular weight, silver nanowires with uniform size and good morphology can be prepared by using high molecular weight PVP as dispersant and growth direction inducer. Finally, silver nanowires with excellent morphology were prepared by selecting suitable mixed solvent system and related technological parameters. The average length of silver nanowires was 100 渭 m, the average diameter was 70 nm, and the aspect to diameter ratio was up to 1 400. The transparent electrode was prepared by coating silver nanowires with different specifications on glass. The results showed that the transparent electrode prepared by silver nanowires with high aspect ratio had good performance by measuring the square resistance and visible light transmittance. When the silver nanowire transparent electrode is treated at a certain temperature, it is found that the silver nanowires are fused at the node position, which makes the square resistance decrease obviously, but the transmittance is not changed. Finally, the transparent electrode with good performance is selected to make the liquid crystal cell, and then the intelligent glass is made. The effects of liquid crystal content, liquid crystal film thickness and illumination intensity on the optoelectronic properties of smart glass were discussed. An intelligent glass sample with a threshold voltage of 20 V and a transmittance of 74% at 550 nm wavelength was obtained.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;TQ171.1
【参考文献】
相关期刊论文 前1条
1 易早;李恺;牛高;罗江山;陈善俊;易有根;唐永建;;聚乙烯吡咯烷酮相对分子质量对银纳米结构的影响[J];强激光与粒子束;2010年10期
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