阅读说明：本技术 颜色变化程度最小的n型离子存储层，使用其的电致变色器件及其制备方法 (N-type ion storage layer with minimum color change degree, electrochromic device using same and preparation method thereof ) 是由 何嘉智 梅建国 于 2019-09-06 设计创作，主要内容包括：本发明公开了一种用于电致变色器件(ECD)的离子存储层,在ECD器件运行期间颜色变化程度最小(MCC)。在一些实施例中,离子存储层由与p型电致变色(EC)层互补的n型金属氧化物材料组成,EC层例如由p型EC聚合物制成的EC层。在一些实施例中,离子存储层可以通过以下方式被调整为MCC,通过调整离子存储层使其总电荷密度高于相应EC层的总电荷密度,和/或调整离子存储层使其着色效率低于相应EC层的着色效率。本发明公开了用于制备离子存储层的方法,包括用于制备具有低着色效率的高度结构化的金属氧化物的方法。本发明还公开了包含MCC离子存储层的ECD器件。(An ion storage layer for an electrochromic device (ECD) is disclosed that has a minimal degree of color change (MCC) during operation of the ECD device. In some embodiments, the ion storage layer is composed of an n-type metal oxide material complementary to a p-type Electrochromic (EC) layer, such as an EC layer made of a p-type EC polymer. In some embodiments, the ion storage layer may be tuned to MCC by tuning the ion storage layer to have an overall charge density higher than that of the corresponding EC layer, and/or tuning the ion storage layer to have a coloration efficiency lower than that of the corresponding EC layer. Methods for making ion storage layers, including methods for making highly structured metal oxides with low coloring efficiency, are disclosed. The invention also discloses an ECD device comprising the MCC ion storage layer.)

1. An electrochromic device, comprising:

a working electrode comprising an electrochromic layer comprising a p-type electrochromic material, the electrochromic layer having a coloring efficiency and a total charge density; and

a counter electrode including an ion storage layer comprising an n-type metal oxide material, the ion storage layer having a coloring efficiency and an overall charge density;

wherein:

the coloring efficiency of the electrochromic layer is greater than that of the ion storage layer; or

The total charge density of the counter electrode is greater than the total charge density of the electrochromic layer; or

The coloring efficiency of the electrochromic layer is greater than that of the ion storage layer, and the total charge density of the counter electrode is greater than that of the electrochromic layer.

2. The electrochromic device of claim 1, wherein said ion storage layer has a coloration efficiency of 50cm or less²C^-1。

3. The electrochromic device of claim 2 wherein said electrochromic layer has a coloration efficiency of at least 100cm²C^-1。

4. The electrochromic device of claim 2 wherein said electrochromic layer has a coloration efficiency of at least 200cm²C^-1。

5. The electrochromic device of claim 2 wherein said electrochromic layer has a coloration efficiency of at least 300cm²C^-1。

6. The electrochromic device of claim 1, wherein said ion storage layer has a coloration efficiency of 40cm or less²C^-1。

7. The electrochromic device of claim 6 wherein said electrochromic layer has a coloration efficiency of at least 100cm²C^-1。

8. The electrochromic device of claim 6 wherein said electrochromic layer has a coloration efficiency of at least 200cm²C^-1。

9. The electrochromic device of claim 6 wherein said electrochromic layer has a coloration efficiency of at least 300cm²C^-1。

10. The electrochromic device of claim 1, wherein said ion storage layer has a coloration efficiency of 30cm or less²C^-1。

11. The electrochromic device of claim 10 wherein said electrochromic layer has a coloration efficiency of at least 100cm²C^-1。

12. The electrochromic device of claim 10 wherein said electrochromic layer has a coloration efficiency of at least 200cm²C^-1。

13. The electrochromic device of claim 10 wherein said electrochromic layer has a coloration efficiency of at least 300cm²C^-1。

14. The electrochromic device of any of claims 1-13, wherein the total charge density of said ion storage layer is equal to or greater than one time the total charge density of said electrochromic layer.

15. The electrochromic device of any of claims 1-13, wherein the total charge density of said ion storage layer is at least 2 times the total charge density of said electrochromic layer.

16. The electrochromic device of claim 1, wherein said n-type metal oxide comprises an amorphous metal oxide.

17. The electrochromic device of claim 1 wherein said n-type metal oxide comprises Nb₂O₅。

18. The electrochromic device of claim 1 wherein said Nb is₂O₅Is amorphous in the ion storage layer.

19. The electrochromic device according to any of claims 1-13 and 16-18, wherein the p-type electrochromic material comprises an electrochromic polymer.

20. The electrochromic device of claim 19 wherein said ion storage layer has an overall charge density equal to or greater than an overall charge density of said electrochromic layer.

21. The electrochromic device of claim 1 wherein said electrochromic layer operates in a full charge state and said ion storage layer operates in an intermediate charge state when said electrochromic device is in operation.

22. A preparation method of an electrochromic device is characterized by comprising the following steps:

preparing an electrochromic layer comprising a p-type electrochromic material;

preparing an ion storage layer comprising an n-type metal oxide; and

adjusting the ion storage layer, the electrochromic layer, or both the ion storage layer and the electrochromic layer such that the ion storage layer operates only in a mode with a minimum degree of color change when the electrochromic device is in operation.

23. The method of claim 22, wherein the electrochromic layer and the ion storage layer each have a total charge density, and wherein the adjusting comprises forming the electrochromic layer and the ion storage layer such that the total charge density of the ion storage layer is equal to or greater than the total charge density of the electrochromic layer.

24. The method of claim 23, wherein the adjusting comprises forming the electrochromic layer and the ion storage layer such that an overall charge density of the ion storage layer is at least 2 times greater than an overall charge density of the electrochromic layer.

25. The method of claim 23, wherein the adjusting comprises selecting the p-type electrochromic material and the n-type metal oxide based on different bulk charge densities.

26. The method of claim 23, wherein the thicknesses of the ion storage layer and the electrochromic layer are each determined according to the different total charge densities required for the ion storage layer and the electrochromic layer, respectively.

27. The method of claim 23, wherein said tuning comprises selecting an electrochromic polymer for said p-type electrochromic material.

28. The method of claim 27, wherein the conditioning comprises forming an ion storage layer such that the n-type metal oxide forms an amorphous metal oxide layer.

29. The method of claim 28, wherein the amorphous metal oxide layer comprises α -Nb₂O₅。

30. The production method according to claim 22, wherein the adjusting includes producing a sol of a precursor of the ion storage layer, the sol including:

a salt that is a precursor for forming a metal oxide in the ion storage layer;

a solvent for dissolving the salt; and

at least one ligand, at least one acid, or at least one ligand and at least one acid, selected and used in amounts to control hydrolysis and condensation upon sol gel formation such that the coloring efficiency of the ion storage layer is no greater than 40cm²C^-1；

Coating the sol on a conductive substrate to form a coating layer; and

heating the coating to a temperature of no more than 150 ℃ for at least 1 minute to promote formation of a metal oxide network.

31. The method of claim 22, wherein the electrochromic layer and the ion storage layer each have a coloring efficiency, and wherein the adjusting comprises configuring the electrochromic layer, the ion storage layer, or both the electrochromic layer and the ion storage layer such that the coloring efficiency of the electrochromic layer is greater than the coloring efficiency of the ion storage layer.

32. The method of claim 31, wherein the conditioning comprises causing the ion storage layer to comprise an amorphous metal oxide layer.

33. The method of claim 32, wherein causing the ion storage layer to include an amorphous metal oxide layer comprises:

preparing a sol of a precursor of the ion storage layer, the sol comprising:

a salt that is a precursor for forming a metal oxide in the ion storage layer;

a solvent for adding the salt; and

at least one ligand, at least one acid, or at least one ligand and at least one acid, selected and used in amounts to control hydrolysis and condensation upon sol gel formation such that the coloring efficiency of the ion storage layer is no greater than 40cm²C^-1；

Coating the sol on a conductive substrate to form a coating layer; and

heating the coating to a temperature of no more than 150 ℃ for at least 1 minute to promote formation of a metal oxide network.

34. The method of claim 31, wherein the adjusting comprises selecting the n-type metal oxide such that the ion storage layer has a coloration efficiency of no greater than 50cm²C^-1。

35. The method of claim 34, wherein the adjusting further comprises selecting the p-type metal oxide such that the electrochromic layer has a coloration efficiency of at least 100cm²C^-1。

36. The method of claim 34, wherein the adjusting further comprises selecting the p-type metal oxide such that the electrochromic layer has a coloration efficiency of at least 200cm²C^-1。

37. The method of claim 34, wherein the adjusting further comprises selecting the p-type metal oxide such that the electrochromic layer has a coloration efficiency of at least 300cm²C^-1。

38. The method of claim 31, wherein the adjusting comprises selecting the n-type metal oxide such that the ion storage layer has a coloration efficiency of no greater than 40cm²C^-1。

39. The method of claim 38, wherein the adjusting further comprises selecting the p-type metal oxide such that the electrochromic layer has a coloration efficiency of at least 100cm²C^-1。

40. The method of claim 34, wherein the adjusting further comprises selecting the p-type metal oxide such that the electrochromic layer has a coloration efficiency of at least 200cm²C^-1。

41. The method of claim 34, wherein the adjusting further comprises selecting the p-type metal oxide such that the electrochromic layer has a coloration efficiency of at least 300cm²C^-1。

42. The method of claim 31, wherein the method comprisesTuning includes selecting an n-type metal oxide such that the ion storage layer has a coloration efficiency of no greater than 30cm²C^-1。

43. The method of claim 42, wherein the adjusting further comprises selecting the p-type metal oxide such that the electrochromic layer has a coloration efficiency of at least 100cm²C^-1。

44. The method of claim 34, wherein the adjusting further comprises selecting the p-type metal oxide such that the electrochromic layer has a coloration efficiency of at least 200cm²C^-1。

45. The method of claim 34, wherein the adjusting further comprises selecting the p-type metal oxide such that the electrochromic layer has a coloration efficiency of at least 300cm²C^-1。

46. The method of any of claims 31-45, wherein the adjusting further comprises setting a total charge density of the ion storage layer equal to or greater than one time a total charge density of the electrochromic layer.

47. The method of any of claims 31-45, wherein the total charge density of the ion storage layer is at least 2 times the total charge density of the electrochromic layer.

48. A preparation method of an ion storage layer of an electrochromic device comprises the following steps:

preparing a sol of a precursor of the ion storage layer, the sol comprising:

a salt that is a precursor for forming a metal oxide in the ion storage layer;

a solvent for adding the salt; and

an acid selected and used in an amount to control hydrolysis and condensation when the sol forms a gel;

coating the sol on a conductive substrate to form a coating layer; and

heating the coating to a temperature of no more than 150 ℃ for at least 1 minute to promote formation of a metal oxide network.

49. The method of claim 48, wherein heating the coating comprises heating the coating to a temperature of 20 ℃ to 150 ℃.

50. The method of claim 48, further comprising subjecting the coating to ultraviolet ozone treatment.

51. The method of claim 48, wherein the at least one acid is an organic acid.

52. The method of claim 48, wherein the at least one acid is an inorganic acid.

53. The method of claim 48, wherein the ion storage layer comprises an n-type metal oxide.

54. The method of claim 53, wherein the n-type metal oxide is selected from TiO₂，Ta₂O₅，WO₃，Nb₂O₅，V₂O₅，MoO₃，NiO，ZnO，Co₃O₄，CeO₂，IrOx，MnO₂FeOx and combinations thereof.

55. The method of claim 53, wherein the n-type metal oxide is a mixture of metal oxides, a doped metal oxide, or a mixture of metal oxide and doped metal oxide.

56. The method of claim 54, wherein the n-type metal oxide comprises Nb₂O₅。

57. The method of claim 53, wherein the n-type metal oxide is amorphous.

58. The method of claim 48, wherein the sol is stable in an air environment for at least 1 day.

59. The method of claim 58, wherein the sol is stable in an air environment for at least 30 days.

60. The method of claim 48, wherein the ion storage layer has a coloration efficiency of no greater than 50cm²C^-1。

61. The method of claim 48, wherein the ion storage layer has a coloration efficiency of no greater than 40cm²C^-1。

62. The method of claim 48, wherein the ion storage layer has a coloration efficiency of no greater than 30cm²C^-1。

63. A preparation method of an ion storage layer of an electrochromic device is characterized by comprising the following steps:

preparing a sol of a precursor of the ion storage layer, the sol comprising:

a salt that is a precursor for forming a metal oxide in the ion storage layer; and

a solvent for adding the salt;

determining whether the sol is stable;

processing the ion storage layer using a solution without any stabilizing additives if the sol is stable; and

if the sol is unstable, one or more stabilizing additives are added to the solution to stabilize the sol prior to using the sol to prepare an ion storage layer.

64. The method of claim 63, wherein determining whether the sol is stable comprises determining whether the sol is stable for at least 1 day under standard atmospheric conditions.

65. The method of claim 63, wherein determining whether the sol is stable comprises determining whether the sol is stable for at least 30 days under standard atmospheric conditions.

66. The method of claim 63, wherein determining whether the sol is stable comprises determining whether the sol is stable for at least 6 months under standard atmospheric conditions.

67. The method of claim 63, wherein the adding one or more stabilizing additives comprises adding at least one acid.

68. The method of claim 63, wherein the adding one or more stabilizing additives comprises adding at least one ligand.

69. The method of claim 63, wherein the adding one or more stabilizing additives comprises adding at least one acid and at least one ligand.

70. The method of claim 63, wherein determining whether the sol is stable comprises determining whether agglomeration and/or precipitation occurs in the sol.

71. The method of claim 63, further comprising determining an amount of the one or more additives to be added to stabilize the sol.

72. The method of claim 71, wherein determining the amount of the one or more additives to be added to stabilize the sol comprises performing a titration.

Technical Field

The application relates to the field of electrochromism, in particular to an N-type ion storage layer with minimum color change degree, an electrochromism device using the same and a preparation method thereof.

Background

Electrochromic devices (ECDs) have been applied to various practical products such as building smart windows, auto-dimming rearview mirrors, and electrochromic apertures. Generally, the ECD has a five-layer structure including an Electrochromic (EC) layer, an ion storage (or Counter Electrode (CE)) layer, an electrolyte layer disposed between the EC and CE layers, and a pair of transparent conductive layers, each of which is electrically connected to one of the EC and CE layers, respectively.

Solution processable p-type dopable cathodically coloring electrochromic polymers (ECPs) for use in ECDs, which are colored in an electrically neutral state and transmissive (bleached) in a p-type doped state, have an ever expanding color wheel. P-type ECPs are considered to be only one step away from everyday product applications due to the large number of p-type ECPs with desirable attributes such as high optical contrast, fast response times, long term optical stability, and most importantly solution-processable properties that contribute to increased throughput and increased manufacturing economy. However, this has hampered the progress of device development with the evolving p-type ECPs due to the current lack of CE layers that can be made with low cost and high throughput fabrication methods.

The counter electrode material can be classified into three categories according to its electrochromic behavior: complementary, non-discoloring, and minimal discoloring (MCC) CE materials. The coloring efficiency of complementary CE materials is generally comparable to that of electrochromic materials used in the electrochromic layer of the ECD, all of which have a significant color change during use of the ECD. Electrochromic devices using complementary CE materials typically have lower optical contrast due to the additive effect of the residual color of the CE and electrochromic materials in the bleached state. Non-color changing CE materials are optically passive.

Currently, the most widely studied CE materials are p-type free radical polymers, which require oxidative pretreatment when they are complexed with p-type dopable ECPs. As a non-color-changing material, the p-type radical polymer does not change color. They therefore appear to be good candidates for cooperating with p-type ECPs of high tinctorial efficiency.

Researchers have developed N-alkyl substituted poly (3, 4-propylenedioxypyrrole) (pprodo) as the MCC CE material. N-C18 substituted PPRODOP (coloring efficiency at 555nm as low as 35 cm)² C^-1) Is proposed as a solution processable MCC CE material, and an ECP-magenta (p-type) EC material (coloring efficiency of about 633cm at 555nm wavelength)² C^-1) And (6) pairing. However, pprodo is also a p-type material. PPRODOP is used as CE, and when the PPRODOP is matched with p-type cathode coloring ECP, the PPRODOP must be subjected to electrochemical or chemical pre-oxidation treatment. This additional step of pre-oxidation is disadvantageous from a manufacturability and production cost standpoint when preparing CE layers suitable for use with p-type EC layers.

Disclosure of Invention

In one embodiment, the present disclosure is directed to an electrochromic device comprising a working electrode comprising an electrochromic layer comprising a p-type electrochromic material, the electrochromic layer having a coloring efficiency and a total charge density; a counter electrode including an ion storage layer containing an n-type metal oxide material, the ion storage layer having a coloring efficiency and an overall charge density; wherein: the coloring efficiency of the electrochromic layer is greater than that of the ion storage layer; or the total charge density of the counter electrode is greater than the total charge density of the electrochromic layer; or the coloring efficiency of the electrochromic layer is greater than that of the ion storage layer, and the total charge density of the counter electrode is greater than that of the electrochromic layer.

In another embodiment, the present invention discloses a method for preparing an electrochromic device, the method comprising: preparing an electrochromic layer comprising a p-type electrochromic material; preparing an ion storage layer comprising an n-type metal oxide; and adjusting the ion storage layer, the electrochromic layer, or both the ion storage layer and the electrochromic layer such that the ion storage layer operates only in a mode with a minimum degree of color change when the electrochromic device is operated.

In another embodiment, the present invention discloses a method of manufacturing an ion storage layer of an electrochromic device, the method comprising: preparing a sol of a precursor of the ion storage layer, the sol comprising: a salt that is a precursor for forming a metal oxide in the ion storage layer; a solvent for adding the salt; and an acid selected and used in an amount to control hydrolysis and condensation when the sol forms a gel; coating the sol on a conductive substrate to form a coating layer; and heating the coating to a temperature of no more than 150 ℃ for at least 1 minute to promote formation of a network of metal oxide.

In another embodiment, the present invention discloses a method for preparing an ion storage layer of an electrochromic device, the method comprising: preparing a sol of a precursor of the ion storage layer, the sol comprising: a salt that is a precursor for forming a metal oxide in the ion storage layer; and a solvent for adding the salt; determining whether the sol is stable; processing the ion storage layer using a solution without any stabilizing additives if the sol is stable; and if the sol is unstable, adding one or more stabilizing additives to the solution to stabilize the sol prior to preparing the ion storage layer using the sol.

Drawings

The claims of the present application set forth particular features of the various embodiments. The technical features and technical effects may be better understood by the following detailed description of specific embodiments. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described and illustrated in the accompanying drawings:

fig. 1 is a partial cross-sectional/partial schematic view of an electrochromic product including an electrochromic device (ECD) fabricated in accordance with the present invention;

fig. 2 is a flow diagram of a roll-to-roll process for forming a Counter Electrode (CE) of the ECD;

FIG. 3 is an amorphous (. alpha. -) Nb film subjected to ultraviolet-ozone (UVO) and heat treatment at 150 ℃₂O₅Layer and alpha-Nb heat treated at 150 DEG C₂O₅An X-ray diffraction pattern of the layer;

fig. 4(a) - (d) include the following figures: 4(a) is alpha-Nb annealed at 100 ℃, 150 ℃, 300 ℃ and UVO-150 DEG C₂O₅Cyclic voltammograms of the film; 4(b) is α -Nb in FIG. 4(a)₂O₅A charge density map of the film; 4(c) UVO treated, UVO-150 ℃ treated, 150 ℃ annealed alpha-Nb₂O₅Thin films and 300 ℃ annealed alpha-Nb₂O₅Fourier transform infrared spectroscopy (FTIR) of the thin film; 4(d) is alpha-Nb treated at UVO-150 ℃ under different cycle times₂O₅Thin film and alpha-Nb annealed at 150 ℃ and 300 ℃ respectively₂O₅The charge density (Q) of the film is compared in percent after normalization by the electrochemically aged charge density (Qec);

FIG. 5 is an infrared spectrum of a bare glass substrate;

FIG. 6 is a-Nb₂O₅Atomic microscope (AFM) images of the thin film before (a) and after (b) UVO treatment;

FIGS. 7(a) - (d)) The method comprises the following figures: 7(a) is alpha-Nb in bleached and colored states annealed at 300 ℃ and UVO-150 ℃ respectively₂O₅The UV-visible spectrum of the film; 7(b) is alpha-Nb in bleached and colored states annealed at 300 ℃ and UVO-150 ℃ respectively₂O₅The chromaticity a b (CIE 1976L a b color space) color coordinates of the film; 7(c) is alpha-Nb annealed at 300 ℃ and UVO-150 DEG C₂O₅The coloring efficiency of the film; 7(d) is UVO-150 ℃ alpha-Nb with different thicknesses₂O₅The ultraviolet-visible spectrum of the film;

fig. 8(a) - (d) include the following figures: 8(a) is an electrochromic polymer (ECP) -Black and alpha-Nb₂O₅Cyclic voltammograms of the film; 8(b) is alpha-Nb₂O₅ECP-spectroelectrochemical plot of a black two-electrode device; 8(c) is alpha-Nb₂O₅The film being in bleached state, in colored state and in a bleached alpha-Nb₂O₅ECP-UV-visible spectrum in an intermediate state in a two electrode black device; 8(d) is alpha-Nb₂O₅ECP-graph of the change of optical density and charge density of the black two-electrode device;

fig. 9(a) - (d) include the following figures: 9(a) is alpha-Nb with source table₂O₅Schematic diagram of/ECP-black two-electrode device, source meter for monitoring voltage between ECP black Working Electrode (WE) and Ag/AgCl reference electrode; 9(b) is alpha-Nb₂O₅ECP-cyclic voltammogram of a black two-electrode device; 9(c) is the voltage change on the ECP-black WE during Cyclic Voltammetry (CV) testing; 9(d) is alpha-Nb₂O₅Voltage change on ECP-black during the two-potential step-time absorption (DPSC) test of the ECP-black two-electrode device (note: region (1) of fig. 9(c) is a voltage window of Ewe increasing rapidly, region (2) of fig. 9(c) is a voltage window of Ewe increasing slowly or reaching a voltage plateau with black arrows indicating the starting voltage of the voltage measurement);

FIG. 10 is a cyclic voltammogram of ECP-black in 0.2M LiTFSI (lithium bis (trifluoromethane) sulfonimide), PC (propylene carbonate) solvent;

fig. 11(a) - (f) include the following figures: 11(a) different number of cyclesLower, alpha-Nb₂O₅Summary table of transmission and optical contrast of/ECP-black electrochromic device (ECD) in bleached and colored state; 11(b) is alpha-Nb₂O₅The result of DPSC test of different cycle times of ECP-black ECD under 550 nm; 11(c) is alpha-Nb₂O₅Cyclic voltammogram of ECP-magenta ECD; 11(d) is a-Nb with different cycle numbers₂O₅Summary table of transmission at 550nm and optical contrast for ECP-magenta ECD in bleached and colored state; 11(e) is alpha-Nb₂O₅The result of DPSC test of ECP-magenta ECD at 550nm and different cycle times; 11(f) is alpha-Nb₂O₅Graph of optical density as a function of charge density for ECP-magenta ECD;

FIG. 12 is a-Nb₂O₅A graph of the change in optical density with charge density for the/ECP-black ECD;

FIG. 13 is Nb₂O₅ECP-cyclic voltammogram of black in 0.2M LiTFSI, PC solvent;

FIG. 14 is Nb₂O₅Electrochemical spectrogram of/ECP-magenta flexible device; and

FIG. 15 is an exemplary titanium dioxide (TiO)₂) A cycle map of the ion storage layer.

Detailed Description

In some aspects, the present invention is directed to an electrochromic device (ECD) having a p-type Electrochromic (EC) layer and an n-type minimally-discoloring (MCC) ion storage (or Counter Electrode (CE)) layer. Examples of ECDs from such a combination of EC and CE layers include all-solid flexible thin film type ECDs, as well as ECDs having other structures, such as more rigid ECDs and ECDs employing liquid or gel state electrolytes. As described in detail below, the presently disclosed n-type MCC EC layers may be made of amorphous (α -) metal oxides that can be processed using low temperature (e.g., in the range of about 20 ℃ to about 150 ℃) solution processes and that do not need to be pre-oxidized (as is necessary for p-type CE layers). In some embodiments, low temperature processing may be optimized by ultraviolet ozone (UVO) treatment in an atmospheric environment to help remove unwanted materials (e.g., solvents used to prepare metal oxides). When used, UVO treatment may be performed before, after, and/or during or after the low temperature treatment.

It was determined that no one used an n-type solution processed metal oxide as an MCC CE layer prior to the preparation of MCC CE layers in accordance with the present disclosure, which hampered the solution of the technical problems as mentioned in the background section above (although p-type ECP types are increasing, the cost of using an ECD with an EC layer prepared from an electrochromic polymer layer (ECP) is still difficult to reduce). The n-type MCC CE layer disclosed by the invention can be matched with an ECP EC layer for use, and also can be matched with other types of EC layer materials (such as metal oxide EC materials, transition metal complexes, quantum dots, perovskites and the like) for use.

In some aspects, methods of adapting a UVO and/or low temperature solution processed MCC CE layer for use, e.g., in the ECD described above, are disclosed. In some embodiments, these methods may be used as a method to tune the MCC CE layer to obtain the best performance in the ECD. Examples of such adjustments include adjusting the MCC CE layer to minimize its color change within a normally used ECD, and adjusting the MCC CE layer to achieve a higher color purity for the ECD than can be achieved with conventional CE layers. With respect to maintaining color purity, in some embodiments, the ECD is designed to have a particular color when in a colored state. This can be achieved by selecting one or more p-type ECPs from the p-type ECP color wheel mentioned in the background section above, and then selecting an MCC material with low hue and high transmittance in both neutral and charged states.

The adjusting method disclosed by the invention comprises but is not limited to the following steps: designing and adjusting the MCC CE layer, and/or the corresponding EC layer, such that the charge density of the MCC CE layer is greater than the charge density of the EC layer; designing and adjusting the MCC CE layer such that the MCC CE layer has a lower coloring efficiency than the EC layer; selecting an MCC material having a high transmittance in a neutral state; and selecting an MCC material having a lower hue in neutral and charged states. The total charge density referred to herein is the unit charge density of the relevant layer. In some embodiments, for a particular application, one of the aforementioned tuning methods may be used; in other embodiments, two or more of the foregoing adjustments may be required to achieve the desired results. In some embodiments, the tuning method includes forming a highly gridized α - (metal oxide) CE layer having a relatively low porosity (e.g., compared to a solution-processed metal oxide EC layer).

In some aspects, methods of preparing sol precursors in a sol-gel process that forms highly gridded alpha- (metal oxide) layers, such as for MCC CE layers, such as n-type MCC CE layers, are disclosed. In some embodiments, a method of preparing a sol comprises mixing one or more precursor salts with one or more organic solvents and adding one or more ligands and/or one or more acids to the mixture; wherein the precursor salt is a precursor of the metal oxide in the metal oxide layer, the sol can be stabilized by providing a corresponding amount of one or more ligands and/or one or more acids such that undissolved particles in the sol remain colloidal and do not precipitate from the sol.

These and other aspects of the present disclosure are described in detail below.

Benefits of MCC CE layers fabricated in accordance with the present disclosure include, but are not limited to: having the ability to fabricate the ECD using a high-throughput roll-to-roll manufacturing process; the ability to utilize the increasing p-type ECD library; the ability of the ECD to maintain color purity of the EC layer; and the ability to produce an alpha- (metal oxide) layer that can withstand high levels of ECD bending without cracking.

In the present disclosure, the term "about" when used in conjunction with a corresponding numerical value refers to ± 20% of the numerical value, typically ± 10% of the numerical value, often ± 5% of the numerical value, and most often ± 2% of the numerical value. In some embodiments, the term "about" may indicate the precise numerical value recited.

I. Exemplary ECD and products containing the same

Referring to fig. 1, fig. 1 illustrates a product 100 including an ECD104 made in accordance with the present invention. The product 100 may be any product that includes an ECD including, but not limited to, a vehicle rearview mirror, a sunroof, smart glazings, eyeglasses, an electronic iris, and the like. In the present embodiment, the ECD104 includes a CE layer 108, an electrolyte layer 112, an EC layer 116, a first transparent conductive layer 120, and a second transparent conductive layer 124. Other components of the product 100 may include a first outer layer 128, a second outer layer 132, and a drive circuit 136 for providing a drive voltage to the ECD104 to switch the ECD104 between colored and bleached states. Layers 108, 112, 116, 120, and 124 are described in detail below, respectively.

Adjusting the coloring efficiency of a metal oxide layer

In some embodiments, CE layer 108 includes a desired thickness T forming one or more layers_CEOne or more n-doped metal oxide materials. Exemplary n-doped metal oxides are described in section i.c., below. In addition, section III below describes the use of Nb₂O₅As a detailed example of an n-dopable metal oxide. CE layer 108 may be formed using a special sol-gel process that causes the formed metal oxide to be amorphous and highly networked such that metal oxide CE layer 108 has low porosity. This low porosity does not allow a large amount of ions from the electrolyte layer 112 to intercalate into the metal oxide to effectively cause a color change, which further reduces the coloring efficiency of the CE layer 108. As used herein and in the appended claims, and as is known in the art, the term "tinting efficiency" and similar terms are defined as the relationship between the embedded/extracted charge per unit area as a function of the change in optical density. It is noted that the term "tinting efficiency" encompasses the visible spectrum or the Infrared (IR) spectrum or both, depending on the particular application of the ECD104 in question.

In some embodiments, it is desirable that CE layer 108 be an MCC CE layer, which CE layer 108 can or contributes to its use as an MCC CE layer with a suitable n-doped a- (metal oxide) layer having low coloring efficiency. Thus, as used herein the specification and claims, the term "minimal discoloration" refers to a CE layer, such as CE layer 108, in the bleached and colored state when assembled in an ECDThe visible region of the electromagnetic spectrum, having a transmission (T%) at least higher than 55%. In some embodiments, the transmittance of the MCC CE layer disclosed herein is at least 65%. In some embodiments, the transmittance of the MCC CE layer disclosed herein is at least 75%. In some embodiments, the coloring efficiency of CE layer 108 is greater than the coloring efficiency of EC layer 116. In some embodiments, the coloring efficiency of CE layer 108 in the visible and/or infrared spectral ranges is about 50cm²C^-1Or lower. In some embodiments, the coloring efficiency of CE layer 108 is about 40cm²C^-1Or lower. In some embodiments, the coloring efficiency of CE layer 108 is about 30cm²C^-1Or lower.

One method of preparation for a metal oxide layer (e.g., useful for CE layer 108) is to prepare a homogeneous precursor sol comprising 1) one or more salts that are precursors of the metal oxide layer, 2) one or more polar solvents, 3) one, two, or none of at least one ligand and at least one acid. Both ligands and acids can be used here as stabilizing additives. In some embodiments, to produce a highly structured, low coloring efficiency metal oxide layer from a precursor sol, the precursor sol must be stable to ensure that undissolved particles in the precursor sol remain in colloidal suspension at room temperature and when exposed to the ambient environment. Keeping the precursor sol stable prevents both agglomeration and precipitation of larger particles prior to coating and during gelation, which can lead to the formation of a more porous, more color efficient metal oxide layer, which is undesirable when the metal oxide layer is used as an MCC (e.g., in the CE layer 108 of the ECD104 in figure 1). In some embodiments, the precursor sol is "stable" or in a "stable state" within the meaning of the present invention, meaning that the precursor sol is stored for 6 months at standard atmospheric pressure without agglomeration or precipitation. In some embodiments, the precursor sol is stable or in a stable state, meaning that the precursor sol is stored at standard atmospheric pressure for 30 days without agglomeration or precipitation. In some embodiments, the precursor sol is stable or in a stable state, meaning that the precursor sol is stored at standard atmospheric pressure for at least 1 day without agglomeration or precipitation. Thus, as used in the present specification and claims, a "stabilizing additive" is an additive, alone or in combination with one or more other stabilizing additives, that helps stabilize a precursor sol that otherwise does not meet the desired or necessary stability conditions.

Depending on the particular precursor composition in question, in some embodiments, the precursor sol may be stable without any stabilizing additives. However, in some embodiments, the precursor gum is stabilized by adding a specific amount of one or more stabilizing additives, such as one or both of a ligand (or mixture of ligands) and an acid (or mixture of acids). Whether the precursor sol is stable in the absence of a stabilizing additive can be determined by titration. If the precursor sol is unstable in the absence of a stabilizing additive, the desired amount of each of the one or more stabilizing additives can also be determined by titration based on the composition of the metal oxide precursor and solvent solutions and the particular ligand and/or acid used, and depending on whether the resulting stability is acceptable. The person skilled in the art will readily understand how to perform the titration process and therefore no further description of this process is necessary.

The present invention is not limited to any particular theory or explanation why a stable precursor sol will result in a highly gridized and low porosity metal oxide layer. One possible influencing factor is that the ligands and/or acids cause steric hindrance and/or electrostatic repulsion between the colloidal particles such that the colloidal particles of the stabilized precursor sol remain in suspension, and then, during coating to form the metal oxide layer, these smaller particles arrange themselves into a highly structured grid, rather than first aggregating into larger particles to form a more open grid; in addition, the addition of ligands and/or acids may also affect the rate of hydrolysis and condensation during gelation, which also results in the formation of an amorphous metal oxide layer with a higher degree of meshing.

After the homogeneous precursor sol is prepared and the desired degree of stability is achieved, it can be wet coated onto a suitable substrate (here transparent conductive layer 120 in the present invention). Coating may be carried out in any suitable manner, such as spin coating, dip coating, blade coating, wire bar coating, gravure coating, extrusion coating, screen coating, microgravure coating, slot die coating, and the like. The coating may be of any suitable thickness, such as a single layer coating thickness TCE for CE layer 108 of a single layer coating, or a total thickness TCE for a multi-layer coating for CE layer 108 of a multi-layer coating.

After coating, in some embodiments, the precursor sol coating is heat treated at low temperatures, preferably about 150 ℃ or less, for example in the range of about room temperature (about 20 ℃) to about 150 ℃. These temperatures are particularly suitable for use with a variety of polymeric substrates, such as polyethylene terephthalate (PET), which can be used in any substrate coated with a precursor sol, such as in transparent conductive layer 120. This heat treatment helps remove unwanted components (e.g., organic residues and molecular water) from the metal oxide network. The heat treatment may be performed at a temperature above about 150 c for the particular application, for example, the heated material may withstand such temperatures without any deleterious effects. In some embodiments, the precursor sol coating is maintained at a desired temperature (e.g., within the ranges described above) for a time sufficient to remove a desired amount of the undesired component from the precursor sol coating. In some embodiments, the time may be from 1min to 2h or more. The precursor sol coating may optionally be subjected to an ultraviolet ozone (UVO) treatment before, during and/or after the above-described heat treatment. The UVO treatment may be performed in a suitable UVO chamber, as is well known in the art. In some embodiments, the UVO treatment is performed in an atmospheric environment. The optional UVO treatment step can help remove all organic materials in the precursor sol coating except the metal oxide mesh. Specific UV parameters may be selected for a particular sol solution, including UV wavelength, intensity, continuous or pulsed mode. The UVO treatment may be applied before, during or after the heat treatment.

Adjusting relative Total Charge Density of CE and EC layers

In some embodiments, an MCC CE layer is used for CE layer 108 including ECD104 as in fig. 1, and CE layer 108 and EC layer 116 are designed in conjunction with each other such that CE layer is primarily only effective in the intermediate charge state, while EC layer is effective in the full charge state. In other words, only a portion of the total charge of the CE layer is used to cause the full color change of the EC layer. For example, in the case of an ECD having a ratio of 1:2 of the total charge density of the EC layer and the CE layer, only 50% of the total charge of the CE layer is required to completely discolor the EC layer. In this manner, the EC layer 116 may operate in a fully colored/bleached state, while the CE layer 108 operates in a partially colored/bleached state. Since the total charge of the CE layer is only partially changed, it does not undergo a complete color change, thereby contributing to the MCC characteristics of the CE layer. Thus, in some embodiments, the EC layer 116 may dominate substantially all of the color change of the ECD104, while the CE layer 108 has little effect on the color change, particularly if the CE layer material is selected to have a high transmittance throughout the intermediate charging process. The relative total charge densities of the CE layer 108 and the EC layer 116 are adjusted in combination such that the CE layer has a higher total charge capacity than the EC layer, thereby achieving the adjustment goal.

In some embodiments, the material/layer of CE layer 108, e.g., an n-dopable α - (metal oxide) (layer), has a total charge density equal to or greater than 1 times the total charge density of EC layer 116. In some embodiments, the material/layer of CE layer 108, e.g., an n-dopable α - (metal oxide) (layer), has a total charge density equal to or greater than 2 times the total charge density of EC layer 116. In some embodiments, the material/layer of CE layer 108, e.g., an n-dopable α - (metal oxide) (layer), has an overall charge density that is 3 times or more the overall charge density of EC layer 116. The relative total charge density of CE layer 108 and EC layer 116 may be.

One way to adjust the overall charge density of the CE layer 108 and the EC layer 116 is to select materials/layers with different bulk charge densities. It is noted that the bulk charge density may vary depending on the number of sub-layers used to compose a CE layer, such as the CE layer 108 of the ECD104 in fig. 1. This is why the examples in the above paragraph are presented in terms of materials and layers. The followingIntroduction of Nb₂O₅The bulk charge density of the MCC CE layer is described. As an example of selecting different bulk densities, assume thickness T of CE layer 108_CEAnd thickness T of EC layer 116_ECEqually, the bulk charge density of one, the other or both of the CE and EC layers may be selected to be adjusted such that the overall charge density of the CE layer is greater than 1 times the overall charge density of the EC layer, or at least 5 times greater than the overall charge density of the EC layer. For the same thickness of CE layer 108 and EC layer 116 (e.g., T)_CE＝T_EC) The CE layer has an overall charge density that is greater than 1 times the overall charge density of the EC layer, at least 5 times greater than the overall charge density of the EC layer, or at least 5 times greater than the overall charge density of the EC layer.

Another way to adjust the relative overall charge densities of the CE layer 108 and the EC layer 116 is to select the thickness T of the CE layer 108 in consideration of each other while taking into account the bulk charge densities of the respective materials/layers_CEAnd thickness T of EC layer 116_EC. For example, assuming that the bulk charge densities of the CE layer 108 and the EC layer 116 are the same and that the bulk charge density does not vary with layer thickness, the thickness T of the CE layer is such that the total charge density of the CE layer is greater than 1 times the total charge density of the EC layer_CENeeds to be correspondingly larger than the thickness T of the EC layer_EC. Similarly, to make the total charge density of CE layer 108 5 or more times the total charge density of EC layer 116, the thickness T of the CE layer_CEThe thickness T of the CE layer is required_EC5 times or more than 5 times. Similarly, the thickness T of the CE layer is such that the total charge density of the CE layer 108 is 10 times or more than 10 times the total charge density of the EC layer 116_CEThe thickness T of the CE layer is required_EC10 times or more than 10 times.

As described above, either of these two ways of adjusting the relative total charge capacity may be used under appropriate conditions. These two approaches can also be used together to obtain the greatest variability in adjusting the relative total charge density.

Exemplary materials for i.c.mcc CE layer and precursor sol

As described above, in some embodiments, CE layer 108 may be composed of a metal oxideThe MCC CE layer of (1). Examples of suitable metal oxides for CE layer 108 include, but are not limited to: TiO 2₂，Ta₂O，WO₃，Nb₂O，V₂O，MoO₃，NiO，ZnO，Co₃O₄，CeO₂，IrO_x，MnO₂And FeO_xAnd the like, and combinations thereof, wherein x ═ 2 or 3. Some of the foregoing metal oxides and other metal oxide corresponding precursor salts can include, but are not limited to: ti (OCH (CH)₃)₂)₄，TaCl₅，Ta(OC₂H₅)₅，(Ta[N(CH₃)₂]₅)，WCl₆，Nb(OC₂H₅)₅，VCl₃，VO(OCH(CH₃)₂)₃，Mo(OH)₆,Ni(NO₃)₂·6H₂O，Zn(CH₃COO)₂·2H₂O，Co(NO₃)₂·6H₂O，Cr(NO₃)₃，CrCl₃，Cr(C₅H₇O₂)₃，FeCl₃，FeNO₃，RhCl₃，IrCl₃，WCl₃，Mn(CH₃COO)₂，MnCl₂And Ce (NH)₄)₂(NO₃)₆And the like, as well as combinations thereof. Generally, suitable metal oxides may comprise any one or more metal elements selected from elements of groups 3 to 5 and groups IB to VIIB of the periodic table of elements. Many n-type metal oxides are materials with low coloring efficiency. They remain highly transparent in the neutral state and change color during the reduction process. In some embodiments, especially when used in conjunction with p-type ECPs, it is desirable for n-type metal oxides to be used as MCC CE layers, exemplary n-type metal oxides including Ta₂O₅，Nb₂O₅And M_OO₃And the like. Suitable n-type metal oxides may be mixed metal oxides or doped metal oxides, or a combination of mixed metal oxides and doped metal oxides, or more than one of these types.

Suitable solvents for preparing the precursor sol of the present invention include, but are not limited to, polar solvents including alcohols, ethers, and ketones. Specific examples include one of isopropyl alcohol, ethanol and acetone and a combination of at least two thereof. When mixed with one or more solvents to prepare the precursor sol, the concentration of the one or more salts can range from about 0.01mol/L to about 10.0 mol/L.

Exemplary ligands for use in preparing the precursor sols disclosed herein include, but are not limited to, organic acids, alcohols, ethers, amines or esters, acetic acid, glycols, glycol ethers, citric acid, polyethylene glycols (e.g., polyethylene glycol 400), ethyl acetate, ethylenediamine tetraacetic acid, lactic acid, and the like. A particular ligand may be used alone or may be used in conjunction with one or more other ligands. In some embodiments, no ligand may be used. When a ligand is used, the concentration of the ligand in the solution may be in the range of about 0.001mol/L to about 10mol/L or in the range of about 0.1mol/L to about 1.0 mol/L.

Exemplary acids suitable for use in preparing the precursor sols disclosed herein include, but are not limited to, organic acids such as acetic acid, citric acid, lactic acid, acrylic acid, formic acid, oxalic acid, uric acid, malic acid, carboxylic acid, sulfonic acid, poly (4-styrenesulfonic acid), and inorganic acids such as HCl, HNO₃，H₃PO₄，H₂SO₄，H₃BO₃，HF，HBr，HClO₄And HI and the like. The particular acid may be used alone or may be used with one or more other acids. In some embodiments, no acid may be used.

The mixing of the precursor sol may be performed in any suitable manner, such as ultrasonic mixing, and the like. When ultrasonic mixing is employed, the mixing time may be in the range of, for example, about 1 minute to 60 minutes, although other mixing times may be used.

Exemplary materials for the i.d.ec layer

The EC layer 116 may be made of any suitable EC material, such as a P-doped material. In some embodiments it is desirable for CE layer 108 to have low coloring efficiency, while in these embodiments it is desirable for EC layer 116 to have high coloring efficiency. Thus, the coloring/bleaching of the ECD100 is almost entirely by EC layer 116. In some embodiments, the EC layer 116 has a color change efficiency of at least 100cm²C^-1. In some embodiments, the EC layer 116 has a color change efficiency of at least 300cm²C^-1. In some embodiments, the EC layer 116 has a color change efficiency of at least 600cm²C^-1. In some embodiments, the EC layer 116 comprises p-type ECP. In some embodiments, the p-type ECP may be a black ECP (referred to herein as ECP-black) having the following structure.

Wherein R may be 2-ethylhexyl.

In some embodiments, the p-type ECP may be a magenta ECP (referred to herein as ECP-magenta) having the following chemical structure:

wherein R may be 2-ethylhexyl.

Those skilled in the art will readily appreciate that the above are only two examples of currently available p-type ECPs, as well as other p-type ECPs that are currently available and that may become available in the future.

In some embodiments, the EC layer 116 may include materials other than ECP, such as metal oxides, transition metal complexes, quantum dots, perovskites, and the like.

Other Components of the exemplary products

Referring again to fig. 1, the electrolyte layer 112 may be any suitable type of electrolyte layer, such as a solid electrolyte layer (e.g., a solid polymer layer), a gel electrolyte layer, or a liquid electrolyte layer. Suitable salts in these layers include, but are not limited to, lithium salts, which are well known in the art. Although the benefits of some embodiments of the present invention are derived in some respects from an all-solid electrolyte, the composition of electrolyte layer 112 is not critical, and any known composition of electrolyte layer 112 may be used, as long as it is suitable for the intended purpose.

Either of first transparent conductive layer 120 and second transparent conductive layer 124 can be constructed in any suitable manner, such as a thin transparent conductive layer (not shown) formed on a suitable transparent substrate (not shown), such as a polymer film (e.g., PET). Transparent conductive layer structures suitable for use in either of the first transparent conductive layer 120 and the second transparent conductive layer 124 are well known in the art and will be understood by those skilled in the art without requiring a detailed description thereof.

The first outer layer 128 and the second outer layer 132 can be any transmissive layer suitable for the product 100 of the present invention. In many applications, such as windows, skylights, and eyewear, first outer layer 128 and second outer layer 132 each include a glass structure that can provide the desired rigidity to product 100 with sufficient strength for environmental conditions. The glass structure may comprise glass that is uncoated or coated with one or more suitable coatings, such as scratch and/or anti-reflective coatings and the like. In mirror type applications, either first outer layer 128 or second outer layer 132 typically includes a mirror surface (not shown in the figures), which may be present on either side of the outer layer. Suitable outer layer constructions for the first outer layer 128 and the second outer layer 132 are well known in the art, and a detailed description thereof is not necessary to understand the present invention for those skilled in the art.

The driving circuit 136 may be any suitable circuit that provides a suitable voltage (including 0V) to the ECD104 via the first transparent conductive layer 120 and the second transparent conductive layer 124. Depending on the materials of the CE layer 108 and the EC layer 116, a suitable voltage may be-1.0V to +1.0V, or-1.5V to +1.5V, or-3.0V to +3.0V, or-4.5V to +4.5V, etc. The drive circuit 136 may include a binary switch or a variable switch (not shown) (e.g., a voltmeter) to vary the voltage applied to the ECD104 to vary the degree of coloration/bleaching. The switch may be manually controlled by a person or automatically controlled, for example based on ambient lighting conditions and/or time, etc. Circuit configurations suitable for the driver circuit 136 are well known in the art, and a detailed description thereof is not necessary to understand the present invention for those skilled in the art.

Scaled-up fabrication of ECD with metal oxide MCC CE layer

As described above, some embodiments of the present disclosure are beneficial in that ECDs can be manufactured using high-throughput processes, such as roll-to-roll manufacturing. For example, the solution processed CE layers disclosed herein, formed by simple coating and low temperature processing, are suitable for a variety of materials, and may be suitable for highly flexible ECDs based on polymer films; whereas conventional CE layer processing temperatures are 300 ℃ or higher, polymer films cannot withstand such high temperatures. Fig. 2 illustrates a roll-to-roll manufacturing process 200 for preparing a CE ion storage layer of the ECD236, such as the CE ion storage layer 108 for the ECD104 of fig. 1.

Referring to fig. 2, a transparent conductive layer 204, which is the same as or similar to the first transparent conductive layer 120 of the ECD104 shown in fig. 1, is formed through an electrode layer roll 208 in a previous step and then further formed into an electrochromic device 236. The transparent conductive layer 204 may include a flexible substrate (not shown), such as a polymer substrate (e.g., PET), a transparent conductive layer (not shown), such as a substrate coated with tin oxyfluoride (FTO), Indium Tin Oxide (ITO), or Aluminum Zinc Oxide (AZO). As the transparent conductive layer 204 moves, a homogeneous precursor sol 210 is coated onto the transparent conductive layer, using a knife-type coating apparatus 215 in this embodiment, to form a coating 212 of a desired thickness. The homogeneous precursor sol 210 can be prepared as described in section i.c., above.

After the coating 212 is formed, it is heat treated by a heat treatment system 220, which may be any suitable heat treatment system known in the art. In some embodiments, the coating 212 is heated by the thermal treatment system 220 to a temperature in the range of about room temperature (about 20 ℃) to about 150 ℃, for example, 1min to 60 min. One skilled in the art would readily understand how to set the heat treatment temperature and heating time required for a roll-to-roll manufacturing process.

The roll-to-roll manufacturing process 200 optionally includes a UVO treatment system 224, the UVO treatment system 224 being used to uv ozone treat the coating 212 under ambient conditions (e.g., an air environment). UVO treatment system 224 may be, for example, a conventional UVO treatment system. Fig. 2 illustrates that UVO treatment system 224 is a step upstream of thermal treatment system 220, which may also be located downstream of and/or concurrent with the thermal treatment system.

After heat treatment and/or UVO treatment, coating 212 has transformed into a highly gridized α - (metal oxide) layer (not shown in the figure) that adheres to transparent conductive layer 204, forming CE film 228. The CE film 228 is rolled onto a CE film roll 232, which may be used in downstream processing steps to produce the ECD236, e.g., the ECD104 of fig. 1 may be produced. 240L shows the ECD236 in a bleached state, while 240R shows the ECD236 in a colored state. In this embodiment, the EC layer (not shown) is composed of ECP-magenta as disclosed in i.d. above.

Example III

III.A amorphous form (alpha-) Nb₂O₅As an n-type cathodically coloring MCC CE

Reagents and materials. Niobium ethoxide (99.95%), ethanol (99.95%), Propylene Carbonate (PC), lithium bis (trifluoromethane) sulfonimide (LiTFSI), poly (ethylene glycol) diacrylate (Mn ═ 575) (PEGDA500), 2-hydroxy-2-methylacetophenone (97%), (HMP), platinum wire (99%, 0.5mm) and leak-free micro Ag/AgCl electrode ET072 were all purchased from commercial sources. All chemicals were used as received unless otherwise stated.

An apparatus. All spectral data were collected by an Agilent Cary 5000UV/vis-NIR spectrophotometer. All electrochemical tests were performed by a Biologic SP-150 potentiostat. The films were prepared by a Laurell spin coater (WS-650Mz-23 NPPB). UVO treatment was performed by a HELIOS-500 UV-ozone cleaning system. alpha-Nb measurement by Veeco dimension 3100 atomic microscope (AFM) and Gaertner variable angle Stokes ellipsometer (L16SF)₂O₅The thickness of the film. In electrochemical experiments with a two-electrode setup, the potential distribution on the ECP black Working Electrode (WE) was monitored using a Keithley 2400 ion source meter. Study of alpha-Nb Using Thermo Nicolet Nexus FTIR₂O₅Organics and water residues in the film.

Preparation and characterization of the films. The niobium ethoxide sol is according to section I.CPrepared by the method described in (1). Processing Nb by sol-gel method using niobium ethoxide solution on ITO/glass or ITO/PET substrate under ambient conditions₂O₅The films were then annealed at different temperatures (100, 150 and 300 ℃) for 10 minutes. alpha-Nb at UVO-150 DEG C₂O₅The films were UVO treated for 20 minutes followed by annealing at 150 ℃ for 10 minutes. The ECP-black and ECP-magenta colors were synthesized. Prior to use, the polymer was dissolved in chloroform and stirred overnight to prepare ECP black (40mg/mL) and ECP magenta (25mg/mL) solutions. The ITO/glass and ITO/PET substrates were cleaned by sonication in acetone and ethanol for 10 minutes and then blown dry by compressed nitrogen. The thin film was prepared by spin coating at a spin speed of 1500 rpm. Measurement of a layer of alpha-Nb by ellipsometry₂O₅The thickness of the film was confirmed by AFM, and its topology was characterized by AFM. As a control experiment, alpha-Nb on ITO/glass substrate₂O₅The film is cut into two pieces, one piece treated by the process suggested above and the other piece untreated. Measurement of two and three layers of alpha-Nb by ellipsometry₂O₅The thickness of the film.

And (4) electrochemistry is carried out. To be coated with ECP-black or alpha-Nb₂O₅The ITO/glass substrate of (2) as the Working Electrode (WE), the non-leaking Ag/AgCl as the reference electrode, the 0.2M LiTFSI PC solution as the electrolyte, and the platinum wire as the counter electrode made a three-electrode device. The three-electrode device was scanned by cyclic voltammetry at a scan rate of 40mV/s to obtain the charge density of the electrodes. The charge density can be calculated as follows:

charge density ═ integral number of rings_jdV/s

Wherein the unit of charge density is mC cm^-2J is the current density (mAcm)^-2) And s is the scan rate (V s)^-1) And V is a voltage (V).

For the two-electrode experiment, ECP-coated ITO/glass WE and alpha-Nb were used₂O₅Coated ITO/glass CE and liquid devices made with 0.2M LiTFSI PC electrolyte or solid devices made with gel electrolyte containing 50 vol% of 0.2M LiTFSI, PC solution and 50% PEGDA mixed. Sweep of cyclic voltammetry test at 40mV/sThe rate proceeds. The voltage between the WE and the non-leaking Ag/AgCl reference electrode was measured using a Keithley 2400 source meter to measure the change in voltage of the WE (ewe) in real time. For CV testing E_weThe data is smoothed at two points to eliminate noise interference.

And (5) manufacturing a device. Mixing PEGDA₅₀₀0.2M LITFSI PC and HMP were mixed overnight in a volume ratio of 5:5:1 in a nitrogen-atmosphere glove box to prepare an electrolyte. All ECP WEs were prepared by spin coating the solution onto an ITO/glass substrate (30X50x 1mm, sheet resistance 8-12 Ω/sq) at a spin speed of 1500rpm and alpha-Nb was prepared by the method described previously₂O₅And (5) CE. They were then transferred to a nitrogen atmosphere glove box. 0.2mL of mixed electrolyte was dropped onto the WE, and the CE was placed on top with the coated material sides of the WE and CE facing each other. After spreading the electrolyte by capillary force, the stacked device was placed under a commercial UV lamp at 365 and 405nm for 15min to crosslink the electrolyte. The device was taken out from the nitrogen atmosphere glove box and sealed by General Electric (General Electric) silicone resin under an atmospheric atmosphere. Flexible devices were fabricated in the same manner on a flexible ITO/PET substrate (sheet resistance 200 Ω/sq).

Preparation of alpha-Nb on ITO/glass substrates by in situ sol-gel reaction₂O₅A film. Dissolving niobium (V) ethoxide in ethanol (with the concentration of 0.19M) to prepare a precursor solution. XRD measurements showed that Nb was produced by annealing at 150 ℃ and 300 ℃₂O₅The film is amorphous (see fig. 3). Study of different Process conditions on alpha-Nb by Cyclic Voltammetry (CV)₂O₅Influence of electrochemical properties of the film. alpha-Nb annealed at 100 ℃ and 150 ℃₂O₅In the thin film, the initial reduction potentials for lithium ion intercalation were-1.15V and-1.0V, respectively, more negative than that of the thin film annealed at 300 deg.C (-0.86V) (see FIG. 4 (a)). alpha-Nb treated by UVO treatment followed by annealing at 150 ℃ (UVO-l50 ℃), UVO-l50 ℃₂O₅The initial potential for lithium ion intercalation of the film (-0.84V) was comparable to that of the film annealed at 300 ℃. alpha-Nb annealing at 100 ℃ and 150 DEG C₂O₅The film acts as an ECD for CE, which may require more electricity to operateAnd (6) pressing.

It is desirable for the CE material to have a high charge density to balance the charge consumption of the electrochromic layer. Referring to fig. 4(b), the charge density can be calculated by integrating the cyclic voltammetry. The charge densities of the films annealed at 100 ℃ and 150 ℃ were both-4.0 mC cm^-2And alpha-Nb treated at UVO-150 DEG C₂O₅The charge density of the film is 7.2 +/-0.9 mC cm^-2Charge density of film annealed at 300 ℃ (6.8 + -0.8 mC cm)^-2) And (4) the equivalent.

The effect of UVO treatment and annealing temperature (see fig. 4(c)) was studied in depth by fourier transform infrared spectroscopy (FTIR). The strong absorption peak of the glass substrate is centered at-900 nm^-1This peak affects the display of the other peaks (see fig. 5). Thus, the spectrogram shows only 4500nm^-1To 1200nm^-1. At-3300 nm^-1A broad absorption peak and H₂O molecules are associated with-O-H stretching of-Nb-OH, whereas-1630 nm^-1The peak at (A) can be attributed to H₂Bending of the O molecule. 1400nm^-1A small peak at (C) may be associated with bending and shearing of the residual organic alkanes (-C-H) in the precursor solution. Initial alpha-Nb₂O₅FTIR spectra of the films at-3300 nm^-1And 1630nm^-1A peak appears at 1400nm^-1A small peak appears indicating the presence of both water molecules and organic matter. UVO treated alpha-Nb₂O₅Thin film at-1400 nm^-1The disappearance of the peak still appears to contain traces of organic on the film annealed at 300 ℃, indicating that the organic residues can be completely removed by UVO treatment. As can be seen from the attenuation (150 ℃) and disappearance (300 ℃) of the-O-H stretching and shearing peaks in the FTIR spectra, alpha-Nb can be removed by annealing at 150 ℃₂O₅Most of the molecular water in the film can be completely removed by annealing at 300 ℃.

FTIR results indicate UVO treatment and solution processing of alpha-Nb₂O₅The photoactivation process of the film is involved. Continuous UV irradiation under an oxygen atmosphere produces strong oxidants such as ozone or atomic oxygen, and the ligands and organic residues in the organic solvent photolyze to form free radicals. TheseThe highly reactive species promote the formation of an amorphous metal-oxygen network, resulting in the coagulation of the metal oxide film. Therefore, a thin film that is free of organic residues and dense will have greater uniformity and reversibility in the redox reaction. Changes in surface morphology and thickness after UVO treatment were characterized by AFM testing (see fig. 6(a) and 6 (b)). And alpha-Nb produced by solution method₂O₅AFM imaging of the films (fig. 6(a)) showed more pronounced graininess and porosity compared to the UVO treated films (fig. 6(b)) and a reduction in thickness from 53.7 ± 5.5nm to 39.2 ± 2.7nm, confirming the photoactivation process that occurred during UVO treatment. Then low temperature (l50 ℃) annealing to remove water molecules, UVO-l50 ℃ treated alpha-Nb₂O₅The film had similar reduction onset potential and charge density to the film annealed at 300 ℃.

In addition, the invention also researches the organic residue pair alpha-Nb₂O₅The effect of the electrochemical stability of the film. Making alpha-Nb by double potential timing current method₂O₅The film was cycled between-1.8V and 2.0V with a voltage conversion interval of 20 s. The charge density was calculated from the chronoamperometry chart for each cycle and normalized by the charge density after electrochemical aging (see fig. 4 (d)). alpha-Nb annealed at 150 ℃ after 500 cycles₂O₅The film lost about 80% of the initial charge density, indicating that the organic residue was detrimental to α -Nb₂O₅Electrochemical stability of the film. In contrast, alpha-Nb annealed at UVO-150 ℃ after 1500 cycles₂O₅The film lost about 28% of the initial charge density. The residual charge density is sufficient to balance the charge in the electrochromic layer. In addition, alpha-Nb annealed by UVO-150 DEG C₂O₅Film-to-film ratio, alpha-Nb annealed at 300 ℃₂O₅The film, had better cycling stability over the first 600 cycles, but its charge density lost about 50% after 1500 cycles. Therefore, the metal oxide bond formation can be more complete by using UVO-150 ℃, thereby forming a compact film with better electrochemical stability.

Referring to FIG. 7(a), evaluation by in situ spectroelectrochemistryalpha-Nb estimated as MCC-CE material₂O₅Hue and transmittance of (a). alpha-Nb annealed at UVO-150 ℃ and 300 ℃ in bleached state₂O₅The transmittance of the film is higher than 85% in most wavelength ranges from 350 to 800nm, except in the near UV region (about 430 nm). Due to alpha-Nb₂O₅The antireflection effect of the coating or the smoothness of the ITO/glass substrate, the transmittance at 370nm is greater than 100%. When alpha-Nb₂O₅alpha-Nb annealing at UVO-150 ℃ and 300 ℃ in reduction of films at-1.8V vs Ag/AgCl₂O₅The film appears light gray in the colored state while its transmission is still greater than 60% in most visible wavelength regions. However, since the charge density is at least 1.4 times higher than that of p-type ECP (e.g., about 2mC cm)^-2To about 5mC cm^-2) Thus, only a fraction of the capacity is needed to balance the charge on the ECP in the color changing device. Thus, alpha-Nb₂O₅The film may maintain its high transmittance characteristics in the ECD.

alpha-Nb using Star-Tek colorimetric software₂O₅The spectra of the films were used to calculate their color space (note: see fig. 7(b), negative and positive values of a correspond to green and red, respectively; negative and positive values of b correspond to blue and yellow, respectively; L represents brightness). alpha-Nb treated at UVO-150 ℃ in the coloured and bleached state₂O₅Annealing treated alpha-Nb with a and b of film both less than 300 deg.C₂O₅Film, indicating alpha-Nb treated with UVO-150 deg.C₂O₅The film had a low hue. alpha-Nb treated as CE with UVO-150 DEG C₂O₅The thin film can provide higher color purity in the ECD.

Because only a fraction of the charge is needed to balance the charge dissipation in the ECP, α -Nb₂O₅The coloring efficiency of the film can be calculated from the initial slope of the optical density (AOD) -charge density curve (see fig. 7 (c)). alpha-Nb treated by UVO-150 DEG C₂O₅Film (16.7 cm)² C^-1) Has a coloring efficiency lower than that of alpha-Nb subjected to annealing treatment at 300 DEG C₂O₅Film (20.7 cm)² C^-1) Is onColor efficiency. Annealing treated alpha-Nb at 300 DEG C₂O₅Compared with the film, the alpha-Nb is treated by UVO-150 DEG C₂O₅The same amount of charge generated by the film results in less color change.

alpha-Nb treated by changing UVO-150 DEG C₂O₅The thickness of the film (number of coatings) was used to adjust the charge density (see table below). With increasing thickness, alpha-Nb₂O₅Film at high L: (>97.0), low a: (<6.0) and low b: (<6.0) at low tones (as in fig. 7d), high transmission is maintained. Thus, UVO-150 ℃ treated alpha-Nb₂O₅The films can be mated with various ECPs of different thicknesses in an unbalanced configuration to assemble an ECD with high optical contrast and high color purity. With alpha-Nb annealed at 300 DEG C₂O₅Compared with a thin film, alpha-Nb treated at UVO-150 DEG C₂O₅The films have similar charge densities, longer cycling stability, lower color shades, and lower coloring efficiency. In the following sections, alpha-Nb treated with UVO-150 deg.C₂O₅The film is illustrated as the MCC CE material for the ECD.

Watch (A)

alpha-Nb treated at UVO-150 ℃ and having different thicknesses₂O₅Thickness, charge density and colorimetry L a b (CIE 1976L a b color space) color coordinates of the film

Number of layers	Thickness/nm	Charge density/mC cm-2	L*	a*	b*
						1	50.03±9.83	7.2±0.9	99.1	-5.1	5.3
2	82.48±8.42	9.4±0.4	97.8	-1.9	3.3
						3	143.19±10.04	13.1±1.7	98.6	-1.3	3.7

III.B use of alpha-Nb₂O₅Example ECD as MCC CE

III.B.1 ECD with Black ECP layer as working electrode

ECD using liquid electrolyte in iii.b.l.i

Assembling a two-electrode liquid device (i.e., ECD in the present invention) to further study α -Nb₂O₅The performance of the film as an MCC-CE for use with ECP. WE is ECP-Black coated ITO/glass substrate and CE is alpha-Nb coating₂O₅The electrolyte is 0.2M LiTFSI, PC solution. WE and CE were electrochemically aged by CV cycling prior to assembly of the device. From CV testingCalculating the ECP-Black layer and the alpha-Nb₂O₅The charge density of the layers was 3.0mC cm each^-2And 8.0mC cm^-2. Therefore, the electrode arrangement of the two-electrode device is unbalanced (see fig. 8 (a)).

In the spectroelectrochemical study, the voltage of the two-electrode device was increased from-1.5V to 2.2V (see FIG. 8 (b)). The broad absorption peak in the visible region (350-800nm) is mainly from ECP-black. Broad absorption peaks in the NIR (near infrared) region (about 900nm and over 1000nm) are associated with polarons and bipolarons, respectively. As the voltage increases, the absorption in the visible region decreases, the absorption of the polaron increases and then decreases, and the absorption of the polaron increases dramatically. These results show that alpha-Nb₂O₅The layer balances the charge in the ECP-black layer during the color switching of the two electrode ECD.

alpha-Nb when the device is oxidized to its bleached state at 2.2V₂O₅The CE was removed for transmission spectrum testing and compared to its own spectroelectrochemical results (see fig. 8 (c)). alpha-Nb of bleached state device₂O₅The transmission spectrum of CE is intermediate between its colored and bleached states, indicating that α -Nb is present in a two-electrode device₂O₅The CE is only partially reduced. alpha-Nb₂O₅The partial reduction of the film is sufficient to balance the charge of the ECP-black when converted to the bleached state. Thus, alpha-Nb₂O₅The film maintains high transmittance and low hue and acts as an MCC-CE during switching of the electrochromic device. Furthermore, the combined coloring efficiency of the two-electrode device was calculated to be-360.0 mC cm with a 95% change in optical contrast^-2(see FIG. 8 (d)).

In a two-electrode system, the potential distribution on the electrodes can affect the optical contrast (Δ T%), switching time, coloring efficiency, and cycle stability of the ECD. To measure the voltage distribution in situ, an Ag/AgCl reference electrode was inserted into a two-electrode setup. When passing through a potentiostat at alpha-Nb₂O₅Applying a device voltage (E) between CE and ECP-Black WE_cell) In the CV test and the two-potential step timing absorption (DPSC) test (refer to FIG. 9(a)), the dissociation was measured by a Keithley source meterVoltage distribution of ECP-black we (ewe) relative to Ag/AgCl due to intercalation/deintercalation of the daughter. The CV of the two-electrode device showed a pair of oxidation-reduction peaks in the vicinity of-2.00V and-1.36V (see FIG. 9 (b)). Referring to FIG. 9(c), after electrochemical aging of the two-electrode device, during CV experiments at 40mV s^-1The scan rate of (c) measures Ewe voltage distribution versus Ag/AgCl. In forward scanning, at different scan rates, within different voltage windows, with E_cellIncreasing from-1.50V to 2.2V, E_weWith a consequent increase. In the voltage window, E, of the region (1) as in FIG. 9(c)_cellIncrease from-1.5V to-0.60V and from 1.33V to 2.20V, Ewe at 17.2mV s, respectively^-1And 13.8mV s^-1Is increasing. E at-0.60V to 1.33V_cellEwe at a relatively slow 4.5mV s (see region (2) in fig. 9 (c))^-1Is increased. A similar phenomenon was observed in the reverse scan of the CV test.

During the reverse scan, when E_cellWhen scanning from 2.20V to 1.25V, or-1.00V to 1.50V, E_weAt 12.8mV s respectively^-1And 34.8mV s^-1Is increasing. When E is_cellWhen scanning from 1.20V to-1.00V, E_weThe potential for Ag/AgCl reached a steady state at-0.40V. At E_weThe voltage interval, which responds at a slower rate or reaches steady state, indicates that the ions are not free to intercalate/deintercalate into/from the ECP-black WE. These phenomena may be attributed to ion traps in the electrochromic layer, which require overpotentials to overcome. In the DPSC experiment, E was also monitored in situ at 2.2V and 1.5V, according to CV and spectroelectrochemistry of the device, as shown in fig. 9(d)_we. When a voltage of 2.2V is applied to the device, E_weThe potential for Ag/AgCl was raised to-0.76V. When E is_cellWhen switching from 2.2V to-1.5V, E_weThe voltage for Ag/AgCl rapidly changed to-0.68V, then gradually increased and finally stabilized at-0.15V. Both voltages were within the stable electrochromic window of ECP-black (fig. 10). Therefore, these conditions were used in the cycling test of the solid state ECD.

All solid state ECD

Simple manufacturing routeIs crucial to reduce production cost. Thus, the alpha-Nb will not be subjected to any pretreatment and electrochemical aging₂O₅The electrodes are used in two-electrode solid state devices. Assembling a two-electrode electrochromic device in which alpha-Nb is added₂O₅The coated ITO/glass was used as CE electrode, ECP-black coated ITO/glass was used as WE electrode, and 50% 0.2M LiTFSI, PC solution and 50% PEGDA were mixed and used as gel electrolyte. Due to the achievement of E in the coloring process_weThe equilibrium was slower than the bleaching process, so the device was held at a constant potential of 2.2V for 15s and-1.5V for 30s to achieve full color change (see fig. 9 (d)). The Δ T% of the device was-45% and decreased by-1.4% up to 3100 cycles (see FIGS. 11(a) and 11 (b)). The time to reach 95% of total bleached Δ T% was 3.4s and the time to reach 95% of total faded Δ T% was 5.6s (see fig. 11 (b)). Solid state alpha-Nb₂O₅95% optical contrast Complex coloration efficiency (. eta.) for ECP-Black ECD_95％) Is 393.3cm² C^-1(see fig. 12).

III.B.2 ECD Using ECP-magenta layer as working electrode

The experimental devices were assembled using ECP-magenta as the WE. The charge density of the ECP-magenta film was-1.8 mC cm^-2Paired alpha-Nb₂O₅The charge density of MCC-CE is-7.2 +/-0.9 mC cm^-2The ECD is assembled in an unbalanced ratio. The CV test results of ECD showed a pair of oxidation-reduction peaks at-1.63V and-1.25V (see FIG. 11 (c)). Switching the device from alpha-Nb using voltages of 1.8V and-1.5V during the DPSC cycling test₂O₅In the cyclic voltammogram of the/ECP-magenta two-electrode device (see FIG. 13), no side reaction of the electrochromic window was observed.

The device can reach 70% Δ T% in the first cycle and can maintain nearly the same contrast in the following 3100 cycles (see fig. 11(d) and 11 (e)). The bleaching time required to reach 95% Δ T% was 1.6s, and the coloring time required to reach 95% Δ T% was 0.5s (see fig. 11 (e)). After 3100 cycles, the coloration time increased to 4.8s, andthe bleaching time (-1.0s) was almost the same as the first cycle (see FIG. 11 (e)). Finally, alpha-Nb₂O₅Eta of/ECP-magenta color_95％Calculated at about 849.5mC cm^-2(see FIG. 11 (f)). High CCE indicates that ECD can achieve high contrast by consuming a small amount of charge. By using alpha-Nb₂O₅As CE material to balance the charge consumption of the electrochromic layer, the ECP-black and ECP-magenta ECDs showed excellent cycling stability in the two-potential cycling experiments.

Low temperature (e.g., less than or equal to 150 ℃) solution processing suitable for flexible substrates is an important factor in achieving large-scale, high-throughput roll-to-roll production of ECDs. UVO-l50 ℃ treated alpha-Nb prepared on ITO/PET substrate₂O₅The film has high uniformity and high transparency. The Δ T at 550nm of the assembled flexible device was 62% (see FIG. 14). Since the sheet resistance of the ITO/PET substrate (about 200. omega./sq) is higher than that of the ITO/glass substrate (about 8. omega./sq to 12. omega./sq), the contrast of the flexible device is low. By way of example of a flexible ECD, it is apparent that high performance α -Nb can be fabricated on flexible substrates₂O₅Layer, prepared to CE via solution process to produce low cost ECD.

And alpha-Nb annealed at 300 DEG C₂O₅Film to solution processed UVO-l50 deg.C treated alpha-Nb₂O₅The charge density of the film is similar to that of the film, but the cycling stability is better. Because of alpha-Nb treated at UVO-l50 DEG C₂O₅The charge density of the thin films is higher than that of ECP and the coloring efficiency is lower than that of ECP, so that they are used as MCC-CE materials to be paired with p-type cathode coloring ECP. alpha-Nb₂O₅ECP-Black and alpha-Nb₂O₅The ECP-magenta solid ECDs all have the characteristics of high contrast, fast switching, high coloring efficiency and stable cycle performance. The development of solution processable, high transparency, reliable CE materials on flexible substrates can be carried out to benefit future electrochromic roll-to-roll manufacturing techniques.

III.C exemplary TiO₂Preparation of ion storage layer

To 2ml of isopropanol in a vial was added 0.66. mu.lT_i(OCH(CH₃)₂)₄To prepare a precursor sol. Then, 100. mu.l of acetic acid was added dropwise to the precursor sol, and the precursor sol was subjected to ultrasonic treatment for 10 min. Spin-coating the precursor sol on the ITO-coated transparent conductive substrate at a rotation speed of 1000rpm to obtain TiO₂A film. And placing the film in an oven at 100 ℃ for baking for 10min, and removing the organic solvent and acetic acid to form a compact film serving as an ion storage layer. FIG. 15 is a cyclic voltammogram of the ion storage layer of this example, from which TiO can be seen₂The film has high storage capacity and high ionic electrochemical reversibility.

Preparation of a D-doped metal oxide ion storage layer

In a vial, 2ml of isopropanol and 10. mu.l of acetic acid were mixed, followed by the addition of 10. mu.l of Ti (OCH (CH)₃)₂)₄And 50. mu.l Nb (OCH)₂CH₃)₅Preparing precursor sol, carrying out ultrasonic treatment on the precursor sol for 10min, and then spin-coating the precursor sol on a transparent conductive substrate coated with ITO at a rotating speed of 1500rpm to prepare Ti-doped Nb₂O₅A film. The film was placed in an oven at 150 ℃ for 30 minutes to further remove the organic solvent and acetic acid.

The embodiments of the present invention have been described in detail above. It should be noted that in this specification and the appended claims, unless specifically stated otherwise, the use of conjunctions in phrases or other representations such as "at least one of X, Y and Z" and "one or more of X, Y and Z" means that any one of the conjunctions in combination can be independently combined in any number and combination of other options, or can be independently combined in any number and combination of other options. According to the general rule mentioned above, the combination consisting of X, Y and Z in the previous example should contain respectively: one or more of X; one or more of Y; one or more of Z; one or more of X and one or more of Y; one or more of Y and one or more of Z; one or more of X and one or more of Z; one or more of X, one or more of Y and one or more of Z.

Various modifications and additions may be made without departing from the spirit and scope of the invention. Each feature of the various embodiments described above may be combined with features of other described embodiments as appropriate to provide a variety of combinations of features in the associated new embodiments. Furthermore, while the foregoing describes a number of separate embodiments, the description herein is merely illustrative of the application of the principles of the present invention. Additionally, although particular methods of the invention may be shown and/or described as being performed in a particular order, the order may be varied within the ordinary skill in practicing the disclosure. Accordingly, this description is to be construed as illustrative only and is not intended to limit the scope of the present invention in any way.

Exemplary embodiments have been disclosed above and shown in the accompanying drawings. It will be understood by those skilled in the art that various changes, omissions and additions may be made to the specifically disclosed aspects of the invention without departing from the spirit and scope of the invention.