• Proceedings of the Materials Research Society of Korea Conference
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• 1993.05a
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• pp.48-49
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• 1993

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1220-1222
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• 1995

In the design of a complementary electrochromic windows based on $WO_3/Li^+$ conducting electrolyte/$V_2O_5$ system, a characterization of electrochromic properties of $WO_3/V_2O_5$ complementary devices as a function of thickness combinations is necessary in order to predict such as the safe operating voltage, the optical modulation range and the optical switching response. In this paper, the effects of $WO_3\;and\;V_2O_5$ thin films thickness combinations on device performance were systematically investigated.

• Journal of the Korean Solar Energy Society
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• v.30 no.3
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• pp.90-97
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• 2010

$TiO_2$ thin films for solar energy utilization were prepared on ITO coated glass by r.f magnetron sputtering with variations of working pressure, oxygen flow rate and annealing temperature. Ion insertion and extraction reaction, and ion storage properties of films were investigated by using a cyclic voltammetry. Transmittance of thin films in as-prepared, colored and bleached states was measured by UV-VIS spectrophotometer. The samples deposited in our sputtering conditions showed poor electrochromic properties. Improvement in ion storage properties of $TiO_2$ thin film was observed after annealing at temperature of $400^{\circ}C$ in air for 2 hours. It was found that $TiO_2$ thin film in electrochromic device could be used as a passive counter-electrode.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.37-40
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• 2004

Electrochromic displays offer the possibility of providing high brightness in reflective mode due to the fact that no polarization of the incident or reflected light is required. The use of appropriately roughened reflective layers can enable the diffuse or Lambertian reflection of light. truly imitating the optical nature of paper as a reading medium. Furthermore, the use of an electrochromic system, essentially an electrochemical device, allows for the integration of charge storage layers, endowing such devices with an on-state memory and associated low power consumption. In this paper we describe the $NanoChromics^{TM}$ system and overview the several strategies employed towards the migration of this technology to flexible display formats.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.157-157
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• 1999

Electrochromic tungsten oxide films were prepared by the electron beam deposition, and the dependence of the electrochemical stability and the optical properties on the titanium concentration, and on the annealing temperature, that was investigated. coloring and bleaching experiments were repeated by cyclic voltammetry in a propylene carbonate solution of LiClO4. Spectrometry was used to assess the stability of the transmittance in the degraded films. Tungsten oxide films with titanium contents of about 10~15 mol% were found to be most stable, undergoing the least degradation during the repeated for coloring and bleaching cycles. The reason for this small amount of degradation was the reduction of lithium ion trapping sites in the films, which results in an increased durability. Tungsten oxide films with titanium contents of about 20 mol% were annealed at 20$0^{\circ}C$ for 1 hour, and this results showed that durability of films were increased.

• Solar Energy
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• v.16 no.2
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• pp.87-96
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• 1996

Electochromic tungsten oxide thin films were prepared on the ITO coated glass by rf magnetron sputtering from a compressed powder tungsten oxide target in an argonoxygen atmosphere. The influence of the preparation conditions, especially the substrate temperature, on the chemical stability of film was investigated. These films were cycled in 0.6M $LiClO_4$ and 0.6M $H_2SO_4$ electrolyte respecitively, and exhibited electrochromic behavior upon the electrochemical insertion and extraction of ion. Among these tungsten oxide thin films, films prepared at a substrate temperature of $150^{\circ}C$ were found to be most stable in terms of cyclic durability.

• Journal of the Korean Chemical Society
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• v.41 no.11
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• pp.575-580
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• 1997

Benzyl viologen was synthesized and the electrochromic properties was examined. At an applied voltage of 2.6 V the electrocoloration was appeared but electrooptical response abruptly decreased after a certain period of time. It was a cause that the quality of the ITO film was degraded, e.g. the conductivity of the ITO film reduced from the original value. The ITO surfaces under some different conditions were observed by XRD and SEM.

• Journal of the Korean Vacuum Society
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• v.8 no.2
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• pp.127-135
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• 1999

Nickel oxide films were prepard by using the electron beam evaporation technique. Coloring and bleaching experiments for cyclic durability were repeated in KOH electrolyte by cyclic voltammetry. Visible spectrophtometry was used to assess the stability of the transmittance in the degraded films. X-ray photoelectron spectroscopy results showed that the grain surface are oxygen-rich compared to the grain interiors in a NiO film. Open circuit memory of colored films is about 400hours in lN KOH. The rate of self discharge was evaluated by measuring the transmittance at 550nm of a fully oxidized NiO film. The rate of self discharge was increased polynomially with time and the film is nearly bleached after about 400hours. It was also found that the degraded film by repeated cycles in the KOH solution changed the grain shape of film surface The film prepared under a vacuum pressure of $3\times10^{-4}$ mbar was found to be rather stable when subjected to the repeated coloring and bleaching cycles in KOH electrolyte. Band theory applied to explain the electrochromic mechanism was discussed.

• Solar Energy
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• v.19 no.1
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• pp.1-8
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• 1999

Electrochromic $WO_3$ thin films were prepared by electron beam deposition. The transmission and durability of films were investigated. Coloring and bleaching experiments were repeated in an electrolyte of propylene carbonate with 0.6M of $LiClO_4$ by cyclic voltammetry. Spectrophotometer was used to measure the transmission in the degraded films. The 5000 ${\AA}$ thick film was found to be the stable after repeated cycles. The durability of the annealed film also showed improvements over unannealed samples. Tungsten oxide films with titanium content of about $10{\sim}15$ mol% was found to be most stable, undergoing the least degradation during the repeated cycles.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.276-280
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• 1999

Electrical properties of electrochromic (EC) InN thin films prepared by rf ion plating were studied. There was a correlation between the electrical properties and the electrochromism in the InN films, particularly, carrier concentration changes were responsible for the electrical resistivity changes of the films due to the electrochromism. These carrier concentration changes were caused by chemisorbed hydroxyl groups and protons. From these results, it was proved that the carrier concentration changes of the InN films was responsible for the electrochromism in the visible and near-infrared region.