Cu@PAA薄膜的结构色及氧空位对有序多孔金属氧化物薄膜物性的影响

发布时间：2018-06-14 10:27

本文选题：薄膜 + 结构色　；参考：《河北师范大学》2016年硕士论文

【摘要】：研究者们发现结构色具有虹彩效应、高反射率、偏振性等优点。近些年大量的实验研究已经证明结构色与微观结构之间有着密切关系,因此,与结构色类似的仿生体系引起了广泛的研究兴趣。人们发现PAA能够制备出具有结构色的薄膜,这些薄膜在防伪、装饰等领域有着广泛的应用。本文采用一次阳极氧化法在磷酸电解液中制备出PAA薄膜,然后以PAA为模板通过交流电化学沉积法将Cu纳米线沉积到PAA薄膜孔洞的底部,得到具有结构色的Cu@PAA纳米复合薄膜。详细的分析了薄膜的微观结构及光学特性。此外,采用二次阳极氧化法制备的PAA薄膜因具有高度有序纳米孔洞阵列得到广泛地应用。正如我们所知,多孔PAA薄膜拥有较大的比表面积致使孔洞内产生大量的氧空位,同时对薄膜的物理性质也有重要的影响,比如铁磁性、电阻开关特性。因此,我们以PAA为基底,利用直流磁控溅射法制备出多孔Cu_2O,TiO_2复合薄膜,通过多种表征手段研究这些多孔复合薄膜的物理性质。其结果分析如下:(1)室温下,采用一次阳极氧化法在磷酸电解液中制备出一系列PAA/Al薄膜,以此为模板再通过交流电化学沉积法沉积了金属Cu,得到具有结构色的Cu@PAA复合薄膜,其颜色饱和度明显的提高了。调控不同的氧化时间,复合薄膜可以得到不同的颜色,且在整个可见光范围内都是可调控的。紫外可见反射光谱显示,随着氧化时间的增加,薄膜的最大反射波长λmax存在红移现象。另外,根据布拉格公式计算的复合薄膜的有效折射率、最大反射波长λmax的理论值与实验结果吻合较好。最后,我们采用有机辅助方法制备出精美多彩的图案。(2)采用直流磁控溅射方法在PAA基底上镀一层Cu_2O薄膜。在无外加偏置磁场的情况下,通过施加具有可逆性和可重复性的电场能够调控Cu_2O/PAA复合薄膜的磁化强度,并且发现复合薄膜具有电阻开关行为。紫外可见光谱测试证明Cu_2O/PAA复合薄膜中存在大量的氧空位。进一步分析表明复合薄膜中导电细丝的形成和断裂与氧空位有着密切的关系。此外,对样品施加电场能够触发到不同阻态,因此,室温下通过施加小电场就能够调控复合薄膜的磁性。(3)采用直流磁控溅射方法在PAA基底上镀一层TiO_2薄膜。紫外可见光谱测试证明TiO_2/PAA复合薄膜中存在大量的氧空位。我们在Ag/TiO_2/PAA/Al器件中发现双极阻变特性,导电细丝的形成和断裂以及器件能被触发到不同阻态都与氧空位有着密切关系。只需我们给器件施加一个小电压,电阻就会产生明显的转换。在制备态复合薄膜中观察到稳定的双极电阻行为能够调控铁磁性的变化。其触发到高阻态下测试的样品的磁化强度是制备态下测试的样品的磁化强度的三倍。对Ag/TiO_2/PAA/Al器件连续十圈的循环测试进一步证明样品的稳定性能。
[Abstract]:The researchers found that structural colors have the advantages of iris effect, high reflectivity, polarization and so on. In recent years, a large number of experimental studies have proved that there is a close relationship between structural color and microstructure. Therefore, biomimetic systems similar to structural colors have attracted extensive research interest. It has been found that PAA can produce structured color films, which are widely used in anti-counterfeiting, decoration and other fields. In this paper, PAA thin films were prepared by primary anodization method in phosphoric acid electrolyte. Then Cu nanowires were deposited into the bottom of the pores of PAA films by alternating current electrochemical deposition using PAA as template. The microstructure and optical properties of the films were analyzed in detail. In addition, PAA thin films prepared by secondary anodization have been widely used because of their highly ordered nano-porous arrays. As we know, porous PAA thin films have a large specific surface area, resulting in a large number of oxygen vacancies in the pores, and also have an important impact on the physical properties of the films, such as ferromagnetism, resistance switching characteristics. Therefore, porous Cu2OTiO-2 composite films were prepared by DC magnetron sputtering on PAA substrate. The physical properties of these porous composite films were studied by various characterization methods. The results are as follows: (1) at room temperature, a series of PAA / Al thin films were prepared by primary anodization method in phosphoric acid electrolyte. Its color saturation is obviously increased. When the oxidation time is different, the composite film can get different color and can be controlled in the whole visible light range. UV-Vis reflectance spectra show that with the increase of oxidation time, the maximum reflectance wavelength 位 max of the film is red-shifted. In addition, the theoretical values of the effective refractive index and the maximum reflection wavelength 位 max calculated by the Bragg formula are in good agreement with the experimental results. Finally, we prepared a colorful pattern by organic assisted method. (2) A CuS2O thin film was deposited on PAA substrate by DC magnetron sputtering. In the absence of an applied bias magnetic field, the magnetization of Cu _ S _ 2O / PAA composite films can be regulated by applying a reversible and repeatable electric field, and it is found that the composite films have resistive switching behavior. UV-Vis spectra show that there are a lot of oxygen vacancies in CuS / PAA composite films. Further analysis shows that the formation and fracture of conductive filament in the composite film are closely related to the oxygen vacancy. In addition, the application of electric field to the sample can trigger different resistance states. Therefore, the magnetic properties of the composite films can be controlled by applying a small electric field at room temperature) the TiO-2 thin films are deposited on PAA substrates by DC magnetron sputtering. UV-Vis spectra show that there are a lot of oxygen vacancies in TIO _ 2 / PAA composite films. We found that the bipolar resistance of Ag- / TiO-2 / PAA- Al devices, the formation and fracture of conductive filaments and the ability of devices to be triggered to different resistance states are closely related to oxygen vacancies. If we apply a small voltage to the device, the resistance will produce a significant conversion. Stable bipolar resistive behavior was observed in the prepared composite films to regulate the change of ferromagnetism. The magnetization of the samples triggered to the high resistance state is three times that of the samples tested in the prepared state. The stability of the sample was further proved by the cyclic test of Ag- / TiO-2 / PAA / Al devices for 10 consecutive cycles.
【学位授予单位】：河北师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O484

【相似文献】