FLEXIBLE PANEL BASED ON ELECTROCHROMIC POLYMERS

• US 20090052006A1
• Filed: 10/02/2008
• Published: 02/26/2009
• Est. Priority Date: 06/25/2001
• Status: Active Grant

• Current Assignee: University of Washington
• Original Assignee: University of Washington
• Inventors: Taya, Minoru, Xu, Chunye, Ma, Chao
• Granted Patent: US 7,826,124 B2
• Time in Patent Office: Days
• US Class Current: 359/275
• CPC Class Codes: C07D 493/04 Ortho-condensed systems
• CPC Class Codes: C08G 2261/1424 containing ether groups, including alkoxy
• CPC Class Codes: C08G 2261/3223 containing one or more sulfur atoms as the only heteroatom, e.g. thiophene
• CPC Class Codes: C08G 61/126 with a five-membered ring containing one sulfur atom in the ring
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/1533 structural features not otherwise provided for
• CPC Class Codes: G02F 1/161 Gaskets; Spacers; Sealing of cells; Filling or closing of cells

Abstract

A flexible electrochromic (EC) panel that is usable for a display device or for other applications in which at least a region of the panel is selectively caused to change opacity. An exemplary EC panel includes an electrochromic working layer or electrode formed of a PProDOT-Me₂ polymer film that is deposited on an indium tin oxide (ITO)-coated polyethylene terephthalate (PET) flexible substrate. Similarly, a counter electrode is formed by depositing a vanadium oxide-titanium oxide (V₂O₅-TiO₂) composite film on another ITO PET coated flexible substrate. An ultraviolet light-cured film sealant is employed to seal the flexible panel and also serves as a spacer between the working and counter electrodes. The film sealant is patterned to define a volume for injecting an electrolyte solution through an inlet port provided in the film sealant. The inlet port is then closed. The EC panel can readily be flexed without damage.

Claims

1. A method for producing a flexible electrochromic panel, comprising the steps of:

(a) depositing a working electrochromic film on a first flexible polymer substrate, the working electrochromic film being selected for its ability to repetitively change between at least;

(i) a first state in which the working electrochromic film exhibits a first transmittance characteristic; and

(ii) a second state in which the working electrochromic film exhibits a second transmittance characteristic, where the first and second transmittance characteristics are substantially different, as a result of the working electrochromic film undergoing a redox process;

(b) depositing an ion storage film on a second flexible polymer substrate, the ion storage film chemically interacting with the working electrochromic film during the redox process, wherein the first and the second flexible polymer substrates are selected for a characteristic flexibility that enables them to be readily bent in an arc;

(c) coupling the first and the second flexible polymer substrates together with a film sealant that is disposed between the first and the second flexible polymer substrates, the film sealant serving as a spacer and defining a volume that is disposed between the working electrochromic film and the ion storage film;

(d) introducing an electrolyte into the volume defined by the film sealant; and

(e) sealing the flexible electrochromic panel to exclude moisture and oxygen, and to maintain the electrolyte within the volume, the flexible electrochromic panel being capable of being bent in a substantial curve without experiencing damage.

2. The method of claim 1, wherein the step of introducing the electrolyte comprises the step of introducing a liquid electrolyte.

3. The method of claim 1, wherein the step of sealing the flexible electrochromic panel comprises the step of curing the film sealant with ultraviolet light.

4. The method of claim 1, wherein the film sealant also defines an inlet port in fluid communication with the volume, and wherein the step of injecting the electrolyte solution into the volume comprises the step of introducing the electrolyte through the inlet port.

5. The method of claim 4, wherein the step of sealing includes the step of sealing the inlet port with a sealant material after the electrolyte has been introduced into the volume.

6. The method of claim 1, further comprising the step of providing terminals on the flexible electrochromic panel to enable a voltage to be applied to the working electrochromic film and to the ion storage film for selectively changing the working electrochromic film between the first state and the second state.

7. The method of claim 1, further comprising the step of coating the first and the second flexible polymer substrates with an indium tin oxide (ITO) coating before the steps of depositing the working electrochromic film and the ion storage film.

8. The method of claim 1, further comprising the step of using a polyethylene terephthalate (PET) material for the first and the second flexible polymer substrates.

9. The method of claim 1, further comprising the step of using a vanadium oxide-titanium oxide composite for the ion storage film.

10. The method of claim 9, further comprising the step of baking the ion storage film deposited on the second flexible polymer substrate at a sufficiently elevated temperature so as to evaporate a liquid from the vanadium oxide-titanium oxide composite that is deposited on the second flexible polymer substrate, while avoiding thermal damage to the second flexible polymer substrate.

11. The method of claim 1, further comprising the step of using a PProDOT-Me₂ polymer for the working electrochromic film.

12. A flexible electrochromic panel, comprising:

(a) a first flexible polymer substrate on which is deposited a working electrochromic film, the working electrochromic film being selected for its ability to repetitively change between at least;

(i) a first state in which the working electrochromic film exhibits a first transmittance characteristic; and

(ii) a second state in which the working electrochromic film exhibits a second transmittance characteristic, where the first and second transmittance characteristics are substantially different, as a result of the working electrochromic film undergoing a redox process;

(b) a second flexible polymer substrate on which is deposited an ion storage film, the ion storage film chemically interacting with the working electrochromic film during the redox process, wherein the first and the second flexible polymer substrates are characterized by being relatively flexible and readily bent in an arc;

(c) a film sealant that couples the first and the second flexible polymer substrates together and serves as a spacer between them, the film sealant defining a volume that is disposed between the working electrochromic film and the ion storage film; and

(d) an electrolyte disposed within the volume defined by the film sealant, the electrolyte providing and conducting ions between the working electrochromic film and the ion storage film during the redox process, to enable the working electrochromic film to change between the first and the second states.

13. The flexible electrochromic panel of claim 12, wherein the film sealant is formed of a material that is cured by exposure to an ultraviolet light, to adhesively join the first flexible polymer substrate to the second flexible polymer substrate.

14. The flexible electrochromic panel of claim 12, wherein the film sealant further defines an inlet port that provides a fluid path into the volume for introducing the electrolyte into the volume.

15. The flexible electrochromic panel of claim 14, further comprising a sealant material introduced into the inlet port to seal the inlet port after the electrolyte has been introduced into the volume.

16. The flexible electrochromic panel of claim 12, further comprising terminals that are electrically coupled to the working electrochromic film and to the ion storage film, for selectively applying a potential to cause the working electrochromic film to change between the first state and the second state.

17. The flexible electrochromic panel of claim 12, wherein the first and the second flexible polymer substrates each include an indium tin oxide (ITO) coating respectively underlying deposits of the working electrochromic film and the ion storage film.

18. The flexible electrochromic panel of claim 12, wherein the first and the second flexible polymer substrates are each formed of a polyethylene terephthalate (PET) material.

19. The flexible electrochromic panel of claim 12, wherein the ion storage film comprises a vanadium oxide-titanium oxide composite.

20. The flexible electrochromic panel of claim 12, wherein the working electrochromic film comprises a PProDOT-Me₂ polymer.

21. The flexible electrochromic panel of claim 12, wherein the electrolyte comprises a liquid electrolyte.

22. The flexible electrochromic panel of claim 12, further comprising a barrier disposed around one or more edges to seal the flexible electrochromic panel, preventing entry of liquid and oxygen from a surrounding environment.