Title Page
Contents
Abstract(국문) 12
ABSTRACT 14
I. INTRODUCTION 16
1. The necessity of the electrochromic research 16
2. The electrochromic principles of tungsten trioxide (WO₃) film. 19
3. Research objective and purpose 21
II. Experiment 22
1. Fabrication of electrodeposition bath solution with various hydrogen ion concentrations (pH) 22
2. A deposition method of WO₃ films with a three-electrode electrodeposition system. 23
3. Investigations 25
III. Results & Discussion 27
1. Current density by electrodeposition at various bath solutions. 27
2. Investigation of the crystalline properties of WO₃ films under the various conditions 30
3. Morphology and roughness characteristics of WO₃ thin films deposited at various pH conditions 32
4. Electrochemical properties of electrochromic films immersed at 1M LiClO₄ + PC electrolyte 36
5. Spectroelectrochemistry properties of electrochromic films immersed at 1M LiClO₄ + PC electrolyte 39
6. Coloration Efficiency (CE) of WO₃ thin films 42
IV. Conclusion 46
V. Reference 47
Table 1. Comparison of normal and colored state between cathodic coloration and anodic coloration materials. 18
Table 2. Summary of the peak current density and diffusion coefficient for WO₃ films deposited using different pH bath solutions. 38
Table 3. Spectroelectrochemistry properties of WO₃ films in 1M LiClO₄ + PC electrolyte at 650-nm wavelength. 41
Table 4. Comparison of the spectroelectrochemistry properties of the WO₃ films prepared using different deposition techniques. 45
Fig 1. Schematic illustration of an electrochromic device in (a) bleached state and (b) colored state. 17
Fig 2. Illustrations of 3D monoclinic crystal structure (a) normal state and (b) H+ ion intercalated state, and 2D amorphous structure (c)...[이미지참조] 20
Fig 3. The schematic diagram of the electrodeposition process with a three-electrodes system. 24
Fig 4. (a) Illustration of spectroelectrochemistry measurement using potentiostat with UV-VIS simultaneously. (b) Images of bleached and... 26
Fig 5. (a) Current density of WO₃ prepared at various pH bath solutions. (b) Variation of deposition rate with bath... 29
Fig 6. XRD patterns of the (a) WO₃ thin film deposited at various pH electrolytes and (b) annealed... 31
Fig 7. The top view FE-SEM images (a-d) and the cross-section images (e-h) of WO₃ thin films deposited at various pHs: pH=1.8(a,... 34
Fig 8. Three-dimensional AFM images of (a) FTO glass, (b) 1.8-WO3, (c) 1.6-WO3, (d) 1.4-WO3, and (e) 1.2-WO3. 35
Fig 9. Cyclic voltammetry curves (2nd cycle) of WO₃ films deposited at various pH baths. CV curves plotted from -1.0V to... 37
Fig 10. (a) CA curve for WO₃ films, voltage range - 1.0V (15s) to +1.0V (15s) in LiClO₄ and PC... 40
Fig 11. Coloration efficiency (CE) of the WO3 thin films deposited at various pH electrolytes. 44