發(fā)布時間：2018-08-13 09:31

【摘要】：銀納米線(AgNWs)具有比表面積大、反應活性高、導電性好等特點,在光學、電學、生物學等領域有良好的應用前景,近年來備受研究者關注。制備銀納米線的報道較多,但是具有小直徑和超高長徑比的銀納米線的合成仍然是一個難題。智能玻璃是一種在電場的開關作用下分別顯示透明和不透明兩種狀態(tài)的功能玻璃,由于其價格昂貴未能得到廣泛的應用。制備具有超高長徑比銀納米線,并將其用于透明電極和智能玻璃,具有重要的學術和應用價值,文獻鮮有這方面的報道。本文研究了制備工藝參數(shù)對銀納米線形貌結構的影響,并采用SEM、XRD、UV-Vis等手段對其進行表征,進而研究了其在智能玻璃中的應用。首先,采用一步醇熱還原法制備了高長徑比且尺寸均勻的銀納米線,研究了制備工藝參數(shù),如AgNO_3濃度、AgNO_3與PVP的配比、反應溫度、成核控制劑用量、溶劑種類、PVP分子量等,對銀納米線的影響,并闡明了具體的影響機制。本文研究發(fā)現(xiàn),AgNO_3的濃度及反應溫度對五次孿晶晶核(MTP)的形成具有重要的影響,進而影響產物的均勻性。AgNO_3與PVP的配比較低時易于產生折線形狀的銀納米線,其可能原因在于銀納米線端面形成新的孿晶晶核,繼而生長出新的銀納米線。研究還發(fā)現(xiàn),溶劑對銀納米線的生長影響巨大,分別采用乙二醇、1,5-戊二醇及1,3-丁二醇為溶劑制備了銀納米線,其形貌有顯著差別,我們從反應速率角度闡述了原因。此外,相對于低分子量,使用分子量較高的PVP作為體系分散劑和生長方向誘導劑,可制得尺寸均勻、形貌較好的銀納米線。最后,通過選擇適宜的混合溶劑體系及相關工藝參數(shù),制備了形貌優(yōu)異的銀納米線,平均長度為100μm,平均直徑為70 nm,長徑比高達1400。將不同規(guī)格的銀納米線涂覆在玻璃片上制備透明電極,測試方塊電阻和可見光透過率,發(fā)現(xiàn)采用具有高長徑比的銀納米線制得的透明電極的性能較好。將銀納米線透明電極在一定的溫度下處理,發(fā)現(xiàn)在節(jié)點位置銀納米線存在融合現(xiàn)象,使得方塊電阻明顯下降,而透光率基本沒有變化。最后,選擇性能良好的透明電極制作成液晶盒,進而制作出智能玻璃。探討了液晶含量、液晶膜厚度、光照強度等工藝參數(shù)對智能玻璃光電性能的影響。優(yōu)化工藝,制得了閾值電壓為20 V且在550 nm波長處透過率達到74%的智能玻璃樣品。
[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.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB383.1;TQ171.1

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相關期刊論文 前1條

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本文編號：2180578