- 學位論文
The Study of Electrochromic Device Using Tungsten and Nickel Oxide Films by Physical Vapor Deposition
The Study of Electrochromic Device Using Tungsten and Nickel Oxide Films by Physical Vapor Deposition
摘要
本研究之目的在於在可撓性基板(PET)上製備多層薄膜(IZO/NiO/Ta2O5/WO3/IZO)的電致變色元件。WO3作為主要電致變色材料、Ta2O5為固態電解質、NiO則為離子儲存層其中，外圍以IZO包夾作為透明導電層使用。實驗共可分為兩部分，為選取沉積各層薄膜的最佳化參數，實驗的第一部份為各層薄膜性質之研究，研究範圍包括沉積速率、結構分析、光學性質分析、電性分析與化學成分分析等，而使用之儀器有表面輪廓儀、X光繞射儀、拉曼光譜儀、紫外-可見光譜儀、能量散射光譜儀與X射線光電子能譜儀等。 在實驗第二部分分別對於氧化鎢與氧化鎳之電致變色與離子儲存的效果。實驗可分為定電壓測試與循環伏安法測試，再結合變色前後的可見光穿透率即可得知通入單位電量可對薄膜光學性質造成變化的程度。 經過以上兩部份的各層材料分析後，由其中選出製備電致變色元件的最佳化參數。在研究最後利用選出之參數成功製備出可撓性電致變色元件。
並列摘要
WO3 is known to be an electrochromic material which can switch its color between transparent (bleach state) and dark blue (color state) by externally applied voltages. In this study, a stack of IZO/NiO/Ta2O5/WO3/IZO electrochromic device was fabricated on flexible substrate (polyethylene terephthalate, PET) by sputtering. Before stacking all layers, each material was separately deposited on a substrate and tested for their structure, compositions, properties and functions. These characterizations for materials are carried out by the following instruments: surface profiler and FE-SEM to inspect the thickness and surface morphology; XRD and Raman spectrometers to examine microstructures; EDX and XPS for the study of chemical compositions; UV-visible-NIR spectrometer for the assessment of optical properties; 4-point probe and Hall effect sensor to measure the electrical resistivity. The electrochromic function was achieved by the chemical insertion of cations (Li+) and electrons into WO3 and NiO layers before stacking. The potential static and cyclic voltammetry then is used to test the efficiency of color change in the devices. Based on the transparency of films by UV-visible-NIR spectroscopy, coloration efficiency and energy consumption in electrochromic function, we can determine the optimal sets of process parameters in sputtering. These parameters are crucial in the fabrication of flexible electrochromic devices by current PVD technologies for the display in mobile devices.