電沈積法製作氧化鎢奈米級薄膜之特性分析、最佳化與應用研究

In this study, electrodeposition method was used to fabricate WO3 electrochromic thin film. To obtain better electrochromic property of device, the solution was aged with different days before depositing process. Furthermore, some thin films were annealed to explore its effect on the electrochromic property of the device. The experiments of this study were divided into three parts. The first part was to use a two-electrode electrodepositing system to form WO3 thin film and find the start voltage of electrodeposition. The fixed voltage mode was used to fabricate the WO3 thin film. The second part was to explore the difference of the electrochromic property of thin film deposited by different ageing time. Finally, some thin films were annealed in the third part to observe the variety of properties including colored/bleached charge, coloring efficiency and current leakage difference. According to the experimental results, the starting voltage for depositing film is about 0.922 V and the best colored/bleached electric voltage is 2.5 V. The thickness of WO3 thin film is about 300 nm when the operating parameter has been controlled at 1.5 V and 2 minutes. The surface roughness of thin films before annealing is about 1~1.5 nm, and it reduced to about 1 nm after annealing process. The four days aged of solution before depositing thin film can achieve the best electrochromic properties, which makes the thin film have the transmittance difference of 54.3%, optical density difference of 0.48, and coloring efficiency of 37.3 cm2/coul and the recovery rate of 95%. The thin film annealed at 100℃ makes the devices have relatively poor color efficiency and recovery rate, about 14.1 cm2/coul and 35%, respectively. According to the electrical measurements of the films annealed at 300℃, it has been proved that the devices have higher current leakage and a narrow hysteresis region, which will make the colored and bleached of thin film is difficult to develop.