DAST-石墨烯复合薄膜的制备及光电特性研究

发布时间：2018-04-22 03:37

本文选题：DAST + 石墨烯　；参考：《电子科技大学》2015年硕士论文

【摘要】：近年新材料技术的快速发展,使THz探测技术成为了一种重要的技术,由此也推动了THz技术的发展,使之在世界范围引起了研究热潮。但是,非制冷太赫兹探测器的研究进展缓慢。传统上,相关的探测器使用无机型热敏感膜材料,其对太赫兹波段的吸收较弱,难于满足非制冷太赫兹探测的需要。为此,本文首先合成出了4-(4二甲基氨基苯乙烯基)甲基吡啶对甲基苯磺酸盐(DAST)非线性有机材料。在此基础上,把DAST与石墨烯分别通过原位和非原位复合的方法,制备出新型的DAST-石墨烯复合材料,并将这些材料通过旋涂工艺制备成薄膜。本文系统地研究了所制薄膜的晶相形貌、红外及太赫兹光谱、紫外-可见光光谱、拉曼光谱、热敏电阻变化等。相关研究还未见国内外文献报道。本文的具体研究成果如下:(1)利用原位复合方法在DAST合成过程中掺入石墨烯,从而合成出DAST-石墨烯原位复合材料,并利用元素分析、红外测试等多种手段对合成的DAST产物进行了测试。结果显示合成的产物的确为非线性有机材料DAST。(2)在复合过程中,氧化石墨烯中的O原子与DAST中苯环上的H原子形成氢键,电子通过氢键转移使氧化石墨烯在80oC的低温下发生了还原反应,这是一种新发现的氧化石墨烯的还原反应。通过该反应使DAST与石墨烯紧密地结合在一起。与之相比,非原位形成的氢键数量远低于原位复合过程,使DAST与石墨烯的结合能力弱,由此导致DAST-石墨烯非原位复合薄膜的光学、电学性能明显弱于原位复合薄膜。在光学方面,石墨烯的加入使复合薄膜在可见光至THz波段吸收明显增强。复合薄膜的远红外光谱吸收峰还出现蓝移现象。在电学方面,与DAST薄膜相比,原位复合薄膜的电阻值(7.6×106Ω)下降了4至5个数量级,而非原位(1.13×1010Ω)仅下降1至2个数量级,原位复合薄膜导电性能更为优良,同时原位复合薄膜电阻温度系数(TCR)(-0.0279 K-1)绝对值最大,能够满足微测辐射热计的性能要求。(3)对具有不同石墨烯浓度的复合薄膜的形貌、光学及电学性能进行了研究。发现在5%浓度左右的原位复合薄膜的形貌更好,浓度小于5%会出现DAST大量结晶,浓度大于5%石墨烯对DAST的红外吸收峰有抑制作用。此外,5%浓度下复合薄膜还具有较好的综合热敏电阻性能,而低浓度下的导电能力不足,高浓度下的成膜质量低,说明5%的石墨烯浓度为该复合薄膜的较优化浓度。
[Abstract]:With the rapid development of new material technology in recent years, THz detection technology has become an important technology, which has also promoted the development of THz technology, which has caused a worldwide research boom. However, the progress of uncooled terahertz detectors is slow. Traditionally, the related detectors use thermosensitive film materials without aircraft type, and the absorption of terahertz band is weak, so it is difficult to meet the need of uncooled terahertz detection. Therefore, in this paper, the nonlinear organic materials of 4-butadimethylaminophenylvinyl) pyridine p-methylbenzene sulfonate were synthesized firstly in this paper. On this basis, a new type of DAST- graphene composite was prepared by in-situ and non-in-situ recombination of DAST and graphene, and thin films were prepared by spin-coating process. The crystal phase morphology, infrared and terahertz spectra, UV-Vis spectra, Raman spectra, thermistor changes of the films were systematically studied in this paper. Relevant studies have not been reported at home and abroad. The concrete research results of this paper are as follows: (1) DAST- graphene in-situ composites were synthesized by in-situ recombination method with graphene in the process of DAST synthesis, and elemental analysis was used to prepare DAST- graphene in-situ composites. The synthesized DAST products were tested by IR and other methods. The results show that the synthesized product is indeed a nonlinear organic material DAST.2.In the process of recombination, O atoms in graphene oxide form hydrogen bonds with H atoms in benzene rings in DAST. The reduction of graphene oxide at low temperature by hydrogen bond transfer in 80oC is a newly discovered reduction reaction of graphene oxide. Through this reaction, DAST and graphene are tightly bound together. In contrast, the number of hydrogen bonds formed in situ is much lower than that in in-situ recombination process, which makes the binding ability of DAST and graphene weak, resulting in the optical and electrical properties of DAST- graphene non-in-situ composite thin films are obviously weaker than those of in-situ composite films. In the optical aspect, the absorption of the composite film from visible light to THz band is obviously enhanced with the addition of graphene. The far-infrared absorption peaks of the composite films also show blue shift phenomenon. In electrical aspect, compared with DAST film, the resistance of in-situ composite film decreases by 4 to 5 orders of magnitude, while that of in situ composite film decreases only by 1. 13 脳 1010 惟), and the conductivity of in situ composite film is better than that of in situ composite film. At the same time, the temperature coefficient of resistance of in-situ composite films (TCR-0.0279 K-1) is the largest, which can meet the performance requirements of microbolometer. The morphology, optical and electrical properties of composite films with different graphene concentrations have been studied. It is found that the in-situ composite films with 5% concentration have better morphology. When the concentration is less than 5%, there will be a large number of crystallization of DAST, and the concentration of more than 5% graphene can inhibit the infrared absorption peak of DAST. In addition, the composite film has good comprehensive thermistor performance at 5% concentration, but the conductivity at low concentration is insufficient, and the film forming quality is low at high concentration, which indicates that 5% graphene concentration is the optimum concentration of the composite film.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O613.71;TB383.2

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