NiO_x:W电致变色薄膜研究及在无机全固态器件中的应用

发布时间：2018-05-18 06:05

本文选题：无机全固态电致变色器件 + 反应磁控溅射　；参考：《中国建筑材料科学研究总院》2017年硕士论文

【摘要】：电致变色材料能够在外加电压的条件下通过阳离子和电子的注入与抽出实现自身光学性能的可逆变化。NiO_x是一种典型的阳极电致变色材料,与其他阳极变色材料相比,NiO_x在循环寿命和着色效率等方面具有很大的优势,但存在褪色态透过率低、锂离子存储量难与阴极变色层匹配等问题,限制了其在器件中的应用。国外的研究已经证明,钨元素掺杂能够改善NiO_x的性能,但在大多数关于W掺杂NiO_x薄膜的研究中,样品的制备采用共溅射法,在固定Ar/O2比例的条件下进行,缺少关于氩氧比、工作气压等工艺参数对薄膜影响的研究,并且共溅射不适合大面积规模化镀膜生产。本文利用直流反应磁控溅射技术,使用摩尔比4:1的镍钨合金靶材,在不同的工艺条件下制备NiO_x:W薄膜,研究氩氧比和工作气压等反应磁控溅射镀膜工艺对薄膜成分价态、形貌结构以及性能的影响。此外,Li+是参与电致变色化学反应的必要物质之一,锂化是将Li+引入器件的过程,本课题将寻找合适的锂化工艺,并以NiO_x:W为阳极层,尝试制备无机全固态电致变色器件。反应磁控溅射制备获得的NiO_x:W薄膜由NiO、Ni_2O_3和WO_3的混合物组成。固定工作气压不变,增加镀膜过程中的氧气流量,薄膜中WO_3含量上升,沉积速率降低,颗粒尺寸减小。薄膜的结晶程度因面心立方结构的Ni O减少,无定形态的Ni_2O_3含量上升而降低,NiO的晶格常数因W6+与Ni2+发生置换而增大。同时,因Ni2+被氧化形成更多的Ni3+,薄膜的光学透过率下降,光学带隙整体上随氧分压上升而减小。由光谱椭偏测试拟合分析获得NiO_x:W薄膜折射率(λ600 nm)和消光系数随氧分压上升而增大。固定镀膜过程中的氩氧比不变,工作气压上升,样品中NiO含量上升,但面心立方结构的NiO转变为非晶态,薄膜的结晶程度降低。随工作气压增大,薄膜表面上的缝隙增多,结构更为疏松。由于Ni2+占镍元素总量的比例增加及薄膜致密程度的变化,样品的透射率随工作气压增大而上升。光学带隙以及由光谱椭偏法分析得到的折射率和消光系数,总体上都随工作气压增大而提高。锂化程度对器件的驱动电压、着色效率以及光调制幅度有显著的影响。制备的器件FTO/LiyWO_3/电解质层/NiO_x:W/ITO在波长550nm处着色态透过率为3.9%,褪色态透过率为60.2%,光调制幅度达到56.3%,着色效率为1.54cm2/C。
[Abstract]:Electrochromic materials can realize the reversible change of their optical properties through the implantation and extraction of cations and electrons under the condition of applied voltage. NiOx is a typical anodic electrochromic material. Compared with other anodic discoloration materials, nio _ x has a great advantage in cycle life and coloring efficiency, but it has some problems such as low fading state transmittance and difficult matching of lithium ion storage with cathode chromotropic layer, which limits its application in devices. It has been proved that tungsten doping can improve the properties of NiO_x. However, in most of the studies on W doped NiO_x films, the sample was prepared by co-sputtering under the condition of fixed Ar/O2 ratio, and the ratio of argon to oxygen was missing. The influence of working pressure and other technological parameters on the film is studied, and co-sputtering is not suitable for large-scale coating production. In this paper, NiO_x:W thin films were prepared by DC reactive magnetron sputtering (RMC) with the target material of Nickel-tungsten alloy at 4:1 molar ratio under different technological conditions. The valence states of the films were studied by reactive magnetron sputtering process, such as argon / oxygen ratio and working pressure. The influence of morphology, structure and properties. In addition, Li is one of the necessary substances to participate in electrochromic chemical reaction. Lithium is the process of introducing Li into the device. In this paper, we will find a suitable lithiation process and try to fabricate the inorganic all-solid-state electrochromic device with NiO_x:W as anode layer. The NiO_x:W thin films prepared by reactive magnetron sputtering are composed of NiO _ 2O _ 3 and WO_3. When the working pressure is constant, the oxygen flow rate increases, the WO_3 content in the film increases, the deposition rate decreases and the particle size decreases. The crystalline degree of the thin films decreases due to the decrease of nio in face-centered cubic structure, the increase of amorphous Ni_2O_3 content and the decrease of lattice constant of nio due to the substitution of W _ 6 and Ni2. At the same time, as Ni2 is oxidized to form more Ni3, the optical transmittance decreases, and the optical band gap decreases with the increase of oxygen partial pressure. The refractive index (位 600nm) and extinction coefficient of NiO_x:W thin films are obtained by the fitting analysis of spectroscopic ellipsometry, and the extinction coefficient increases with the increase of oxygen partial pressure. In the fixed coating process, the argon / oxygen ratio is constant, the working pressure increases, the NiO content in the sample increases, but the NiO with face-centered cubic structure changes to amorphous state, and the crystallinity of the film decreases. With the increase of the working pressure, the gap on the surface of the film increases and the structure becomes more loose. Due to the increase of the ratio of Ni2 to the total nickel element and the change of the densification of the film, the transmittance of the sample increases with the increase of the working pressure. The optical band gap and the refractive index and extinction coefficient obtained by spectroscopic ellipsometry increase with the increase of the working pressure. The degree of lithiation has a significant effect on the driving voltage, coloring efficiency and optical modulation amplitude of the device. The FTO/LiyWO_3/ electrolyte layer / NiOx: W / ITO has a coloring state transmittance of 3.9 at wavelength 550nm, a fading state transmittance of 60.2, a light modulation amplitude of 56.3 and a coloring efficiency of 1.54 cm ~ 2 / C.
【学位授予单位】：中国建筑材料科学研究总院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN383.1;TB383.2

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