• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.232.1-232.1
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• 2014

The green displays are the human friendly displays, the nature friendly displays, and the economical displays. Electrochromic displays are low cost and environmental devices because they do have more choice of colours and use much less power. The elements of the electrochromic devices consist of at least two conductors, an electrochromic material and an electrolyte. The optical properties were obtained using the optical contrast between the transparency of the substrate and the coloured state of the electrochromic materials. These devices can be fully flexible and printable. Due to the characteristics of the high coloration efficiency and memory effects, the electrochromic devices have been used in various applications such as information displays, smart windows, light shutters and electronic papers. Among these technical fields switchable mirrors have been received much attention in the applicative point of view of various electronic devices production. We have developed a novel silver (Ag) deposition-based electrochromic device for the reversible electrodeposition (RED) system. The electrochromic device can switch between transparent states and mirror states in response to a change in the applied voltage. The dynamic range of transmittance percent (%) for the fabricated device is about 90% at 550 nm wavelength. Also, we successfully fabricated the large area RED display system using the parted electrochromic cells of the honey comb structure.

• 한국전기전자재료학회논문지
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• 제37권1호
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• pp.1-10
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• 2024

Direct use of sunlight through the glass windows is an efficient way to reduce the energy consumption related to the heating, cooling, and lighting. Introduction of near-infrared modulating properties through colloidal doped metal oxide nanocrystals into the classical electrochromic materials accelerates the development of next-generation electrochromic devices. There has been a steady enhancement in the performance of electrochromic devices, necessitating a review of the recent progress in next-generation electrochromic devices employing doped metal oxide nanocrystals. This review provides an overview of the current developments in next-generation electrochromic smart windows utilizing colloidal doped metal oxide nanocrystals, with a focus on the key factors for achieving these advanced windows. Colloidal doped metal oxide nanocrystals are a crucial component in realizing and bringing to market the next generation of electrochromic windows, though further research and development are still required in this regard.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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• pp.295-298
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• 1996

In this study, we have fabricated all solid state electrochromic devices using WO$_3$ film as the working electrode, V$_2$O$\_$5/ film as the counter electrode and PEO-LiClO$_4$-PC film as the solid electrolyte. The WO$_3$ thin films for working electrode and V$_2$O$\_$5/ thin films for counter electrode were deposited onto ITO glass by vacuum evaporation and were shown good electrochromic and state properties after 1x10$\^$5/ cycles. PEO-LiClO$_4$-PC polymer electrolyte can easily be formed into thin films, do not absorb in the visible region of the light. Therefore, such electrolyte have electrochromic properties suitable for large-scale all solid-state electrochromic devices. All solid-staeelectrochromic devices fabricated in this polymer electrolyte have optical modulation of 20%∼30% at 1.5 V.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 추계학술대회 논문집
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• pp.120-123
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• 1993

This paper describes the deposition and characteristics of electrochromic tungsten oxide thin films for electrochromic smart windows. Tungsten Oxide thin films(WO$_3$) are deposited by thermal evaporation techniques. By varying deposition parameters, WO$_3$ thin films exhibit different optical properties. The electrochromic devices are consist of ITO glass/ WO$_3$ thin films/ LiClO$_4$-propylene carbonate electrolyte/ counter electrode. The electrochromic properties of tungsten oxide thin films with different deposition condition ale investigated.

• 한국분말재료학회지
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• 제27권1호
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• pp.58-62
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• 2020

Recently, electrochromic devices (ECDs) have gathered increasing attention owing to their high color contrast and memory effect, which make them highly applicable to smart windows, auto-dimming mirrors, sensors, etc. Traditional ECDs have a sandwich structure that contains an electrochromic layer between two ITO substrates. These sandwich-type devices are usually fabricated through the lamination of two electrodes and followed by the injection of a liquid electrolyte in the inner space. However, this process is sometimes complex and time consuming. In this study, we fabricated ECDs with a lateral electrode structure that uses only an ITO substrate and an all-in-one electrochromic gel, which is a mixture of electrolyte and electrochromic material. Furthermore, we investigated the EC properties of the lateral-type device by comparing it with a sandwich-type device. The lateral-type ECD shows strong blue absorption as the applied voltage increases and has a competitive coloration efficiency compared to the sandwich-type device.

• 한국전기전자재료학회논문지
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• 제35권3호
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• pp.275-280
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• 2022

An all-solid-state electrochromic film was fabricated by laminating tungsten oxide (WO₃) and nickel oxide (NiO) thin films deposited by a reactive DC magnetron sputtering on flexible ITO films. The influence of oxygen partial pressure on the crystal structure, microstructure, optical properties, and electrochromic properties of WO₃ and NiO thin films were investigated. WO₃ and NiO films showed the best electrochromic properties under the flow of Ar:O₂=80:20 and Ar:O₂=90:10, respectively. The EC film fabricated with an optimized WO₃ and NiO films showed a high coloration efficiency, a fast response time, and a stable optical modulation. It is expected that flexible EC window films will pave the way for the next-generation energy-saving windows.

• 한국전기전자재료학회논문지
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• 제36권1호
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• pp.1-9
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• 2023

According to the recent global warming, it is necessary to use energy efficiently together with eco-friendly energy. The development of alternative technologies is requisite for managing the current energy and climate crises. In this regard, "smart windows," which can control solar radiation, can be used to mitigate energy demands. Electrochromic devices (ECDs) effectively control the amount of solar energy reaching commercial and other living areas and maintain climate conditions via color modulation in response to small external stimuli, such as temperature and light irradiation. However, the performance and the stability of ECDs depend on the state of the electrolyte and sealing of the device. To resolve the aforementioned issues, an ECD was manufactured by using a poly (methyl methacrylate) (PMMA)-based gel polymer electrolyte (GPE), and a laminating method was used to adequately seal the ECD. The concentrations of PMMA, acetonitrile (ACN), and ferrocene (Fc) were controlled to optimize the composition of the GPE to achieve an enhanced electrochromic performance. The fabricated GPE-based ECD afforded high optical contrast (~81.92%), with high electrochromic stability up to 10,000 cycles. Moreover, the lamination method employing the GPE could be used to fabricate large-area ECDs.

• E2M - 전기 전자와 첨단 소재
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• 제9권7호
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• pp.690-695
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• 1996

We have systematically investigated the characterization of V$_{2}$O$_{5}$ thin films as a counter electrode for lithium based complementary electrochromic devices. The V$_{2}$O$_{5}$ thin films were prepared by thermal vacuum evaporation with varing the substrate temperature and film thickness. In electrochromic devices for smart windows, the WO$_{3}$ thin films with 400-800 nm thickness require to be capable of reversibly injection 10-15 mC/cm$^{2}$ of lithium, which is readily accomplished charge-balanced switching in a V$_{2}$O$_{5}$ thin films with 100-150nm thick. The V$_{2}$O$_{5}$ thin films produces considerably small changes in optical modulation properties in the visible and near infrared region(500-1100 nm) compared to the amorphous WO$_{3}$ thin films on 10-15 mC/cm$^{2}$ of lithium injection and the V$_{2}$O$_{5}$ thin films can therefore act as a counter electrode to WO$_{3}$ in a lithium based complementary clectrochromic devices. After 10$^{5}$ coloration/bleaching switching time, the degradation does not occurs and the devices exhibit a stable optical modulation in V$_{2}$O$_{5}$ thin films. It has shown that the injected lithium ion amounts in crystalline V$_{2}$O$_{5}$ thin films with the same thickness is large by 3-5 mC/cm$^{2}$ of lithium compared to the amorphous thin films in the same driving conditions. Therefore, to optimize the device performance, it is necessary to choose an appropriate film thickness and crystallinity of V$_{2}$O$_{5}$ for amorphous WO$_{3}$ film thickness as a working electrode.

• 한국태양에너지학회 논문집
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• 제26권4호
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• pp.55-61
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• 2006

Titanium oxide ($TiO_2$) films are deposited on the indium tin oxide (ITO) substrate in an $Ar/O_2$ atmosphere by using reactive RF (Radio Frequency) magnetron sputtering technique, and Electrochromic properties and durability of $TiO_2$ films deposited at different preparation conditions are investigated by using UV-VIS spectrophotometer and cyclic voltammetry Li+ interalation/deintercalation in $TiO_2$ films shows that the electrochromic properties and durability of as-deposited films strongly depend on gas pressure $TiO_2$ films formed in our sputtering conditions are found to remain transparent, irrespective of their Li+ ion contents. The optimum sputtering conditions for film as passive counter electrode in electrochromic devices are working pressure of $1.0\;{\times}\;10^{-2}\;torr$ and oxygen flow raes of $10{\sim}15\;sccm$, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.505-508
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• 1999

The effect of the heat treatment on electrochromic properties of $MoO_3$ thin films is investigated by studing optical modulation, optical density, response time, and cyclic voltammetry. From the results of XRD analysis, heat-treated at $450^{\circ}C$ in air for 1 hour $MoO_3$ thin films are found to be crystalline while as-deposited film and heat-treated at low temperature (${\leq}300^{\circ}C$) are amorphous. The electrochrornic devices using as-deposited $MoO_3$ films exhibits good electrochromic properties compare to those using the heat treated $MoO_3$ films. It has shown that the heat-treatment affected the stability and the electrochromic properties of $MoO_3$ films.