전기변색소자 적용을 위한 칼코게나이드계 삼원화합물 박막 특성 연구

Abstract

Due to the depletion of fossil fuels and radiation safety problems of nuclear power plants, it is urgent to measure to reduce energy consumption in order to decrease consumption relative to energy production. Recently, a lot of research is being conducted on electrochromic technology, which is one of measures to reduce energy consumption. Smart window, which is one of the typical applications for the electrochromic devices, is an element whose optical properties vary with the electrical energy exerted from the outside, and has advantages such as low energy consumption, stable memory effect, and high discoloration efficiency. These characteristics not only increase energy efficiency in buildings or vehicles, but also increase the environmental and operational convenience. The basic structure of the conventional electrochromic device is composed of the relatively complex structure such as electrode / positive electrochromic material / electrolyte / negative electrochromic material / electrode. WO3 material is typical of the anodically electrochromic material, while NiO is representative of the cathodically electrochromic material. The device is manufactured by inserting ions into electrolyte or electrochromic material during device fabrication. However, the electrochromic devices of such a structure require a lot of production cost or process time because the structure is very complicated with many fabrication processes. Therefore, this thesis intends to use chalcogenide compounds as a method to replace the electrochemical operation and device structure of the conventional electrochromic devices. Chalcogenide materials have been reported to change their optical properties as they change their phase from amorphous to crystalline or vice versa. It can be applied as an electrochromic device by utilizing the changing of the optical characteristics at the time of phase change the property of high-speed set-up and reset, ultimately satisfy the requirements of high discoloration efficiency, high-speed operation, high stability and low manufacturing cost. Using the co-sputtering method, the composition of the three chalcogen elements of sulfur (S), selenium (Se) and tellurium (Te) was changed to produce the ternary chalcogenide thin films for the electrochromic devices. This thesis first proposed an electrochromic device using the ternary chalcogenide thin films, and successfully presented the optimum conditions for electrochromic devices with the proper optical transmittance, optical contrast, switching speed and low power consumption. This study is believed to simplify the complex process and structure of the conventional electrochromic devices, thus reducing process time and cost and significantly reducing power consumption.