COATING PROCESS USING PREMIXED PRINT FORMULATIONS

Abstract

Described are a process for preparing a layer structure for an electrochromic device and a process for preparing an electrochromic device.

Claims

1. A process for preparing a layer structure for an electrochromic device, said process comprising preparing an electrochromic composite layer disposed on a surface of a solid substrate, wherein preparing said electrochromic composite layer comprises the steps of: providing a first suspension comprising nanoobjects comprising one or more electrochromic metal oxides dispersed in a first carrier liquid having a boiling point below 120 C.; providing a second suspension comprising electronically conductive nanoobjects dispersed in a second carrier liquid having a boiling point below 120 C., said electronically conductive nanoobjects not comprising metal oxides; adding together said first suspension and said second suspension to obtain a third suspension comprising said nanoobjects comprising one or more electrochromic metal oxides and said electronically conductive nanoobjects dispersed in a third carrier liquid having a boiling point below 120 C. consisting of said first carrier liquid and said second carrier liquid; forming an ink by admixing to said third suspension: one or more kinds of polymerisable monomers, optionally one or more initiators for initiating radical polymerization of said one or more kinds of polymerisable monomers, at least one electrolyte having cations selected from the group consisting of H.sup.+, Li.sup.+, Na.sup.+, K.sup.+ wherein said at least one electrolyte comprises at least one anion that is different from OH.sup. or at least one cation from the group consisting of Li.sup.+, Na.sup.+ and K.sup.+, an d a solvent capable of dissolving said at least one electrolyte, wherein said solvent has a boiling point of 120 C. or higher forming on said surface of said solid substrate a wet film by applying the formed ink to said surface of said solid substrate; removing said third carrier liquid having a boiling point below 120 C. from the wet film formed on said surface of said solid substrate; and polymerizing the polymerizable monomers on said surface of said solid substrate.

2. Process according to claim 1, wherein said first carrier liquid and said second carrier liquid have the same or different composition and are selected from the group consisting of water, methanol, ethanol, 1-propanol, 2-propanol, 2-butanol, iso-butanol, acetonitrile and propionitrile and mixtures thereof.

3. Process according to claim 1, wherein said electrochromic metal oxides are selected from the group consisting of oxides of Ti, V, Cr, Mn, Fe, Co, Ni, Nb, Mo, Rh, Ta, W, Ir, Ce and mixtures thereof.

4. Process according to claim 1, wherein said first suspension further comprises one or more metal salts of formula (I)
(M.sup.a+).sub.z(R.sup.b).sub.y (I), wherein M.sup.a+ represents a metal cation, R.sup.b represents the corresponding salt anion, a is 2, 3, 4 or 5, b is 1, 2 or 3, z is the least common multiple of a and b, divided by a, and y is the least common multiple of a and b, divided by b, wherein at least a portion of said metal salts of formula (I) is physisorbed on the surfaces of said nanoobjects comprising one or more electrochromic metal oxides, and wherein a molar fraction of metal ions M of said metal salts of formula (I) is in the range of from 0.02 to 6 mol %, based on a total amount of metal in said metal ions M of said metal salts of formula (I) and in said metal oxides in said nanoobjects.

5. Process according to claim 1, wherein said electronically conductive nanoobjects that do not comprise metal oxides are nanowires consisting of materials selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel and alloys of two or more metals selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel, wherein said nanowires have a length in the range of from 1 m to 100 m, and a diameter in the range of from 1 nm to 100 nm, length and diameter in each case being determined by transmission electron microscopy.

6. Process according to claim 1, wherein said first suspension, said second suspension, and said third suspension do not contain an electrolyte having cations selected from the group consisting of H.sup.+, Li.sup.+, Na.sup.+and K.sup.+, which comprises at least one anion which is different from OH.sup. or at least one cation from the group consisting of Li.sup.+, Na.sup.+ and K.sup.+.

7. Process according to claim 1, wherein in said first suspension the concentration of dispersed nanoobjects comprising one or more electrochromic metal oxides is in the range of from 0.1 wt.-% to 20.0 wt.-%, and/or in said second suspension the concentration of dispersed electronically conducting nanoobjects is in the range of from 0.1 wt.-% to 2.0 wt.-%.

8. Process according to claim 1, wherein said first suspension and said second suspension are added together in a volume ratio in the range of from 1:10 to 10:1.

9. Process according to claim 1, wherein said polymerisable monomers are co-polymerizable monomers selected from the group consisting of alkyl acrylates and alkyl methacrylates and from the group consisting of hydroxyalkyl acrylates and hydroxyalkyl methacrylates, and/or said electrolyte is selected from the group consisting of bis(trifluoromethane)sulfonimide, lithium difluorophosphate, lithium hexafluorophosphate, lithium tetrafluroborate, lithium nitrate, lithium bis(flurosulfonyl)imide, lithium bis(trifluoromethane)sulfonimide, lithium trifluoromethane sulfonate, lithium perchlorate, lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium difluorobisoxalatophosphate, and/or said solvent having a boiling point of 120 C. or higher is selected from the group consisting of carbonates, alkyl esters of saturated carbonic acids, polyethers, lactones and dinitriles and mixtures thereof.

10. Process according to claim 1, wherein the step of forming said ink comprises admixing a premixture comprising: one or more kinds of polymerisable monomers, optionally one or more initiators for initiating radical polymerization of said one or more kinds of polymerisable monomers, at least one electrolyte having cations selected from the group consisting of H.sup.+, Li.sup.+, Na.sup.+ and K.sup.+ and anions different from OH.sup., and a solvent capable of dissolving said electrolytes, wherein said solvent has a boiling point of 120 C. or higher to said third suspension.

11. Process according to claim 1 wherein the step of forming said ink comprises mechanical agitation of the ink.

12. Process according to claim 1, wherein said ink comprises said third carrier liquid having a boiling point below 120 C. in an amount of from 42.76 wt.-% to 99.97 wt.-%, said nanoobjects comprising one or more electrochromic metal oxides in a total amount of from 0.009 wt.-% to 12.53 wt.-%, said electronically conductive nanoobjects not comprising metal oxides in a total amount of from 0.001 wt.-% to 0.40 wt.-%, said polymerisable monomers in a total amount of from 0.00006 wt.-% to 40.08 wt.-%, said initiators for initiating radical polymerization of said polymerisable monomers in a total amount of from 0.000002 wt.-% to 1.05 wt.-%, said electrolytes having cations selected from the group consisting of H.sup.+, Li.sup.+, Na.sup.+, K.sup.+ wherein said electrolytes each comprise at least one anion that is different from OH.sup. or at least one cation from the group consisting of Li.sup.+, Na.sup.+and K.sup.+ in a total amount of from 0.001 wt.-% to 1.05 wt.-%, and said solvent capable of dissolving said electrolytes, wherein said solvent has a boiling point of 120 C. or higher, in an amount of from 0.00003 wt.-% to 6.33 wt.-% in each case related to the total weight of the ink.

13. Process according to claim 1, wherein said ink is applied to said surface of said solid substrate by coating or printing, and/or said third carrier liquid having a boiling point of less than 120 C. is removed by exposing the wet film formed on said surface of said solid substrate to air having a temperature in the range of from 20 C. to 120 C., and/or said polymerization is initiated by irradiation having a wave length in the range of from 360 nm to 420 nm in the presence of an initiator which decomposes into radicals when exposed to said irradiation.

14. Process according to claim 1, said process further comprising preparing an ionically conductive separator layer disposed on a surface of said electrochromic composite layer facing away from said solid substrate, wherein preparing said ionically conductive separator layer comprises the steps of: forming on said surface of said electrochromic composite layer a wet film by applying to said surface an ink comprising: one or more kinds of polymerisable monomers, optionally one or more initiators for initiating radical polymerization of said one or more kinds of polymerisable monomers, optionally one or more electrolytes having cations selected from the group consisting of H.sup.+, Li.sup.+, Na.sup.+and K.sup.+, a solvent capable of dissolving said electrolytes, wherein said solvent has a boiling point of 120 C. or higher, and optionally a carrier liquid having a boiling point below 120 C. when said ink contains a carrier liquid having a boiling point below 120 C., removing the carrier liquid having a boiling point below 120 C. from said wet film formed on to said surface of said electrochromic composite layer, and at least partially polymerizing said polymerizable monomers in said ionically conductive separator layer formed on to said surface of said electrochromic composite layer.

15. Process according to claim 14, wherein said solid substrate comprises a first solid substrate, said process further comprising applying a counter electrode layer, wherein applying said counter electrode layer comprises the steps of: preparing or providing a layer assembly comprising a counter electrode layer disposed on a surface of a second solid substrate and optionally an ion conductive separator layer disposed on the surface of said counter electrode layer facing away from said second solid substrate stacking said layer assembly on top of said ionically conductive separator layer of a layer structure prepared by the process according to claim 14, such that a resulting layer structure is obtained having an ionically conductive separator layer between an electrochromic composite layer and said counter electrode layer.

16. Process according to claim 15, said process further comprising attaching a first support layer to said surface of said first solid substrate facing away from said electrochromic composite layer and/or attaching a second support layer to said surface of said second solid substrate facing away from said counter electrode layer, and optionally attaching a third support layer to the surface of said first support layer facing away from said first solid substrate and/or a fourth support layer to said surface of said second support layer facing away from said second solid substrate.

17. Process for manufacturing an electrochromic device, comprising preparing one or more layer structures according to the process of claim 1, or providing one or more layer structures manufactured according to the process of claim 1.

18. Process according to claim 5, wherein said nanowires have a diameter in the range of from 10 nm to 50 nm.

19. Process according to claim 18, wherein said nanowires have a diameter in the range of from 15 nm to 30 nm.

Description

[0295] In the figures:

[0296] FIG. 1 is a schematic representation of a preferred layer structure obtainable by a process according to a third aspect of the present invention

[0297] FIG. 2 is a schematic representation of a first alternative of a process according to the third aspect of the present invention

[0298] FIG. 3 is a schematic representation of a second alternative of a process according to the third aspect of the present invention

[0299] FIG. 4 is a schematic representation of another preferred layer structure obtainable by a process according to a third aspect of the present invention

[0300] The layer structure 100 shown in FIG. 1 comprises [0301] a first solid substrate 101 having an electronically conductive surface layer 103 [0302] an electrochromic composite layer 105 disposed on said electronically conductive surface layer 103 of said solid substrate 101 [0303] an ion-conductive separator layer 107 disposed on the surface of the electrochromic composite layer 105 facing away from the first solid substrate 101 [0304] a counter electrode layer 106 [0305] a second solid substrate 102 having an electronically conductive surface layer 104 upon which said counter electrode layer 106 is disposed.

[0306] The electrochromic composite layer 105 of the layer structure shown in FIG. 1 is prepared as described above and comprises (see enlarged inset on the left side of FIG. 1) [0307] a matrix 105a formed of one or more organic polymers and [0308] dispersed within said matrix 105a: [0309] nanoobjects comprising one or more electrochromic metal oxides, e.g. nanoparticles 105b consisting of a first electrochromic metal oxide [0310] electronically conductive nanoobjects which do not comprise metal oxides, e.g. metal nanowires 105c [0311] at least one electrolyte having cations 105d selected from the group consisting of H.sup.+, Li.sup.+, Na.sup.+ and K.sup.+, e.g. a lithium salt, dissolved in a solvent (not shown) having a boiling point of 120 C. or higher, wherein said electrolyte comprises at least one anion which is different from OH.sup. or at least one cation from the group consisting of Li.sup.+, Na.sup.+ and K.sup.+.

[0312] The ionically conductive separator 107 layer of the layer structure 100 shown in FIG. 1 is prepared as described above and comprises [0313] a matrix 107a formed of one or more organic polymers and [0314] dispersed within said matrix at least one electrolyte having cations 107b selected from the group consisting of H.sup.+, Li.sup.+, Na.sup.+ and K.sup.+, e.g. a lithium salt, dissolved in a solvent (not shown) having a boiling point of 120 C. or higher

[0315] The counter electrode layer 106 of the layer structure 100 shown in FIG. 1 comprises an electroactive material capable of reversibly inserting and releasing ions, e.g. a compound capable of reversibly inserting and releasing lithium ions. Preferably, the counter electrode is a second electrochromic composite layer prepared as described above in the context of the first aspect of the present invention and comprises (not shown in FIG. 1) [0316] a matrix formed of one or more organic polymers and [0317] dispersed within said matrix: [0318] nanoobjects comprising one or more electrochromic metal oxides different from the electrochromic metal oxides in the first electrochromic composite layer, e.g. nanoparticles consisting of a second electrochromic metal oxide, [0319] electronically conductive nanoobjects wherein said electronically conductive nanoobjects do not comprise metal oxides, e.g. metal nanowires [0320] at least one electrolyte having cations selected from the group consisting of H.sup.+, Li.sup.+, Na.sup.+ and K.sup.+, e.g. a lithium salt, dissolved in a solvent (not shown) having a boiling point of 120 C. or higher, wherein said electrolyte comprises at least one anion which is different from OH.sup. or at least one cation from the group consisting of Li.sup.+, Na.sup.+ and K.

[0321] The first and second solid substrates 101, 102 are optically transparent. The surface of the first solid substrate layer 101 upon which the electrochromic composite layer 105 is disposed comprises a layer 103 comprising electronically conductive material, preferably an optically transparent electronically conductive material, e.g. indium-tin oxide (ITO). The surface of the second solid substrate layer 102 upon which the counter electrode layer 106 is disposed comprises a layer 104 comprising an electronically conductive material, preferably an optically transparent electronically conductive material, e.g. indium-tin oxide (ITO).

[0322] The layers 102 and 104 comprising an electronically conductive material at the surfaces of the solid substrates 101 and 103, resp., can be omitted provided that the electrochromic composite layer 105 and the counter electrode layer 106 have sufficient in-plane conductivity.

[0323] A process according to a first preferred alternative of the third aspect of the present invention (as described above) is illustrated in FIG. 2. A preliminary layer structure 200A comprising an electrochromic composite layer 205 (prepared as described above in the context of the first aspect of the present invention) disposed on a surface of a first solid substrate 201 is provided. A first layer structure 200B is obtained by preparing (as described above in the context of the second aspect of the present invention) an ionically conductive separator layer 207 disposed on the surface of the electrochromic composite layer 205 of said preliminary layer structure 200A. Said first layer structure 200B comprises an electrochromic composite layer 205 disposed on a surface of a first solid substrate 201 and an ion-conductive separator layer 207 disposed on the surface of the electrochromic composite layer 205 facing away from the first solid substrate 201.

[0324] A second layer structure 200C comprising an electrochromic composite layer 206 disposed on a second substrate 202 (prepared as described above in the context of the first aspect of the present invention) is provided. Said second layer structure 200C does not comprise an ionically conductive separator layer.

[0325] Said second layer structure 200C is stacked on top of the ionically conductive separator layer 205 of the first layer structure 200B, so that a resulting layer structure 200D is obtained having said ionically conductive separator layer 207 between the electrochromic composite layer 205 of the first layer structure and the electrochromic composite layer 206 of the second layer structure, and said first and second solid substrates 201, 202 form the lowermost layer and the uppermost layer of said resulting layer structure 200D.

[0326] In FIG. 2, merely for the sake of keeping the figure illustrative and clear, second layer structure 200C is drawn smaller relative to layer structures 200A, 200B, 200D. It is however clear for the skilled person that the layer structures to be combined shall have matching surface areas, as shown in resulting layer structure 200D in FIG. 2.

[0327] A process according to a second preferred alternative of the third aspect of the present invention (as described above) is illustrated in FIG. 3. A first preliminary layer structure 300A comprising an electrochromic composite layer 305 (prepared as described above in the context of the first aspect of the present invention) disposed on a surface of a first solid substrate 301 is provided. A first layer structure 300B is obtained by preparing (as described above in the context of the second aspect of the present invention) an ionically conductive separator layer 307a disposed on the surface of the electrochromic composite layer 305 of said first preliminary layer structure 300A. Said first layer structure 300B comprises an electrochromic composite layer 305 disposed on a surface of a first solid substrate 301 and an ion-conductive separator layer 307a disposed on the surface of the electrochromic composite layer 305 facing away from the first solid substrate 301.

[0328] A second preliminary layer structure 300C comprising an electrochromic composite layer 306 (prepared as described above in the context of the first aspect of the present invention) disposed on a surface of a second solid substrate 302 is provided. A second layer structure 300D is obtained by preparing (as described above in the context of the second aspect of the present invention) an ionically conductive separator layer 307b disposed on the surface of the electrochromic composite layer 306 of said second preliminary layer structure 300C. Said second layer structure 300D comprises an electrochromic composite layer 306 disposed on a surface of a second solid substrate 302 and an ion-conductive separator layer 307b disposed on the surface of the electrochromic composite layer 306 facing away from the second solid substrate 302.

[0329] Said second layer structure 300D is stacked on top of the ionically conductive separator layer 307a of the first layer structure 300B, so that a resulting layer structure 300E is obtained having between the electrochromic composite layer 305 of the first layer structure and the electrochromic composite layer 306 of the second layer structure a resulting ionically conductive separator layer 307 which consists of the ionically conductive separator layer 307a of the first layer structure 300B and the ionically conductive separator layer 307b of the second layer structure 300D, and said first and second solid substrates 301, 302 form the lowermost layer and the uppermost layer of said resulting layer structure 300E.

[0330] In FIG. 3, merely for the sake of keeping the figure illustrative and clear, layer structures 300C and 300D are drawn smaller relative to layer structures 300A, 300B, 300E. It is however clear for the skilled person that the layer structures to be combined shall have matching surface areas, as shown in resulting layer structure 300E in FIG. 3.

[0331] The layer structure 400 shown in FIG. 4 comprises [0332] a first solid substrate 401 having an electronically conductive surface layer 403 [0333] an electrochromic composite layer 405 disposed on said electronically conductive surface layer 403 of said solid substrate 401 [0334] an ion-conductive separator layer 407 disposed on the surface of the electrochromic composite layer 405 facing away from the first solid substrate 401 [0335] a counter electrode layer 406 [0336] a second solid substrate 402 having an electronically conductive surface layer 404 upon which said counter electrode layer 406 is disposed.

[0337] The layers 403 and 404 comprising an electronically conductive material at the surfaces of the solid substrates 401 and 402, resp., can be omitted provided that the electrochromic composite layer 405 and the counter electrode layer 406 have sufficient in-plane conductivity.

[0338] Further in the layer structure according to FIG. 4, [0339] a first support layer 409 is attached to the surface of the first solid substrate 401 facing away from said electrochromic composite layer 405, wherein said first support layer 409 is attached to the first solid substrate 401 by applying an adhesive 411 between the first support layer 409 and the surface of the first solid substrate 401 to which said first support layer 409 has to be attached

[0340] and [0341] a second support layer 410 is attached to the surface of the second solid substrate 402 facing away from said counter electrode layer 406, wherein said second support layer 410 is attached to the second solid substrate 402 by applying an adhesive 412 between the second support layer 410 and the surface of the second solid substrate 402 to which said second support layer 410 has to be attached.

[0342] Alternatively (not shown in FIG. 4), [0343] a support layer is attached to the surface of the first solid substrate facing away from said electrochromic composite layer and no support layer is attached to the surface of the second solid substrate facing away from said counter electrode layer, or [0344] a support layer is attached to the surface of the second solid substrate facing away from said counter electrode layer, and no support layer is attached to the surface of the first solid substrate facing away from said electrochromic composite layer.

[0345] Furthermore, it is preferred that a third support layer (not shown) is attached to the surface of the first support layer 409 facing away from the first solid substrate 401 and/or a fourth support layer is attached to the surface of the second support layer 410 facing away from the second solid substrate 402. In this regard it is particularly preferred that a third support layer is attached to the surface of the first support layer 409 facing away from the first solid substrate 401 and a fourth support layer is attached to the surface of the second support layer 410 facing away from the second solid substrate 402.