Method of reducing leakage current in electrochemichromic solutions and solutions based thereon
AssigneeDonnelly Corporation
InventorsDesaraju V. Varaprasad, Hamid R. Habibi, Niall R. Lynam, Padma Desaraju
Life of this patent
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Abstract
The specification discloses electrochemichromic solutions and devices based on the use of from about 5% by volume of a nonpolymeric material having a high volume resistivity and high dielectric constant to reduce leakage current without unduly increasing solution viscosity. In an alternative aspect, high quantities of such materials are used even though solution viscosity increases to the point of preventing room temperature vacuum backfilling in order to take advantage of other features of such solutions.
Claims24
An electrochemichromic cell comprising:
- spaced plates, each having an inwardly facing conductive surface;
- an electrochemichromic solution located in said cell between said inwardly facing conductive surfaces, said solution comprising:
- a solvent;
- a redox chemical pair in solution in said solvent which colors in the presence of an applied voltage and which bleaches to a colorless condition in the absence of an applied voltage;
- said solvent comprising from at least about 5% weight by volume of a nonpolymeric material having a volume resistivity of at least 5.times.10.sup.9 ohm.cm at 25.degree. C. and dielectric constant of at least 15 at 25.degree. C. and 60 hertz.
An electrochemichromic cell comprising:
- spaced plates, each having an inwardly facing conductive surface;
- an electrochemichromic solution located in said cell between said inwardly facing conductive surfaces, said solution comprising:
- a solvent having at least about 25% by volume 2-acetylbutyrolactone;
- a redox chemical pair in solution in said solvent which colors in the presence of an applied voltage and which bleaches to a colorless condition in the absence of an applied voltage;
- said solvent comprising from at least about t5% weight by volume of a nonpolymeric material having a volume resistivity of at least 5.times.10.sup.9 ohm cm at 25.degree. C. and dielectric constant of at least 15 at 25.degree. C. and 60 hertz.
An electrochemichromic cell comprising:
- spaced plates, each having an inwardly facing conductive surface;
- an electrochemichromic solution located in said cell between said inwardly facing conductive surfaces, said solution comprising:
- a solvent;
- a redox chemical pair comprising 0.02 to 0.05 molar of one of methylviologen perchlorate and methylviologen hexafluorophosphate and 0.02 to 0.05 molar 5,10-dihydro-5,10-dimethylphenazine in solution in said solvent which colors in the presence of an applied voltage and which bleaches to a colorless condition in the absence of an applied voltage;
- said solvent comprising from at least about 5% weight by volume of a nonpolymeric material having a volume resistivity of at least 5.times.10.sup.9 ohm cm at 25.degree. C. and dielectric constant of at least 15.degree. to 25.degree. C. and 60 hertz.
An electrochemichromic cell comprising:
- spaced plates, each having an inwardly facing conductive surface;
- an electrochemichromic solution located in said cell between said inwardly facing conductive surfaces, said solution comprising:
- a solvent;
- a redox chemical pair in solution in said solvent which colors in the presence of an applied voltage and which bleaches to a colorless condition in the absence of an applied voltage;
- said solvent comprising from at least about 5% weight by volume cyanoethylsucrose.
A method for reducing leakage current in an electrochemichromic solution which comprises a solvent, a redox chemical pair in solution in said solvent which colors in the presence of an applied voltage and which bleaches to a colorless condition in the absence of an applied voltage, said method comprising:
- introducing at least about 5% weight by volume cyanoethylsucrose into said solvent.
Dependencies are inferred from the claim text.