Electrochromic Glazing

Abstract

The present invention relates to a material having a substrate coated with a first coating, the first coating comprising, starting from the substrate: - a first dielectric coating, - a metallic functional layer based on silver, a blocking layer located above and in direct contact with the silver-based metallic functional layer, said blocking layer being selected from metal layers of one or more elements selected from nickel and chromium, such as Ni, Cr, NiCr, and metal nitride layers of one or more elements selected from titanium, nickel, and chromium, such as NiN, CrN, NiCrN, TiN, a second dielectric coating having at least one conductive oxide layer, the total thickness of the conductive oxide layers of said second dielectric coating being greater than 40 nm.

Description

[Technical Field]

[0001] The present invention relates to the field of electrochromic (EC) glazing. The present invention relates in particular to electrically conductive coatings for electrochromic devices having a silver-based metallic functional layer with improved electrochemical properties. [Background technology]

[0002] Electrochromic devices, and in particular electrochromic glazing, are systems whose optical response can be adjusted under the action of an electric voltage in the visible or infrared range, thus making it possible to obtain easily adjustable, electrically controlled coatings.

[0003] Electrochromic devices are known to be characterized by an electrochromic system having a sequence of at least five layered elements essential to the operation of the device, i.e., the reversible color change following the application of appropriate electrical power. These five layered elements are as follows: - a first transparent electrically conductive coating, - a first active layer acting as an electrode; - electrolyte layer, a second active layer acting as a counter electrode, and - A second transparent electrically conductive coating.

[0004] At least one active layer is based on an electrochromic material.

[0005] These five layered elements are generally in contact with one or two transparent substrates.

[0006] Electrochromic systems fall into three categories: - "All-solid" inorganic technology, - "Hybrid" technology - "All-polymer" technology.

[0007] In "all-solid" electrochromic systems, all layers are made of inorganic solid materials. These systems may have a single substrate. Examples of all-solid EC systems are described in EP 0867752, EP 0831360, WO 00 / 057243, and WO 00 / 071777.

[0008] Hybrid electrochromic systems have an inorganic active layer surrounding an electrolyte layer based on an ion-conducting polymer. These systems traditionally have two substrates surrounding the electrochromic system. Examples of hybrid EC systems are described in EP 0382623, EP 0518754, and EP 0532408.

[0009] In an "all-polymer" electrochromic system, the active layer and the electrolyte layer are based on a polymer.

[0010] The colouring / bleaching in the visible light range, or more generally the change in optical properties, results from the transfer of charges (ions / electrons) between the two active layers.

[0011] The active layer, based on an electrochromic material, can reversibly insert ions. When ions migrate into this layer, its optical properties change, reversibly changing from a bleached state to a colored state. The other active layer can also be based on an electrochromic material.

[0012] Inorganic electrochromic materials are mostly transition metal oxides and are divided into two groups: cathodically coloring oxides that color in the reduced state, such as tungsten oxide (WO), and anodically coloring oxides that color in the oxidized state, such as iridium oxide (IrOx) and nickel oxide (NiOx). A pair of cathodic and anodic electrochromic materials is generally selected, for example, a cathodic material that color in the intercalation state combined with an anodic material that bleaches in the intercalation state.

[0013] The electrolyte layer must have good ionic conductivity and be electrically insulating. The electrolyte in an electrochromic system ensures the passage of mobile ions within their electrochemical stability range. Theoretically, all monovalent ions, such as H, Li, Na, K, Ag, etc., and divalent ions, such as Zn, 2+ etc., and trivalent ions, e.g. Al 3+ etc. can be used. Lithium, alkali or hydrogen salts are particularly suitable.

[0014] For example, if a tungsten oxide (WO3) active layer is in contact with a lithium ion conducting electrolyte layer, when a voltage is applied, Li + Ions migrate between the electrodes. The following electrochemical reaction is observed at the cathode: 6+ O 2- 3(transparent)+xLi + +xe - →Li + x W 6+ 1-x W 5+ x O 2- 3 (blue).

[0015] Voltammetry can be used to determine the voltage range that provides the best contrast between the colored and bleached states. A voltammetric cycle or curve, or voltammetrogram (j = f(V)), consists of tracking the change in current density j over a scan interval of potential. The study of the change in current density is important for the electrochemical behavior of materials. From these curves, the coloring potential (Vcoloring), bleaching potential (Vbleaching), and stability range of the material, corresponding to an oxidation reaction in the anodic part (j>0) or a reduction reaction in the cathodic part (j<0), can be directly estimated.

[0016] Considering that the electrochromic device has a cathodic coloring active layer based on tungsten oxide and an electrolyte layer containing lithium ions, the colored state is observed at 2.3 V and the bleached state at 3.2 V (vs. Li / Li+).

[0017] Considering that the electrochromic device has an anode coloring active layer based on nickel oxide and an electrolyte layer containing lithium ions, the oxidation potential associated with lithium ion intercalation and deintercalation is about 4 V, while the bleaching voltage can be adjusted by doping the nickel oxide with 1 V to 2.5 V.

[0018] Considering known all-polymer EC systems with an electrolyte layer containing lithium ions, the voltage range between the relatively low and relatively high transparent states is 2 V to 4 V vs. Li / Li+.

[0019] Therefore, in these EC systems, the reactions that enable coloring and bleaching occur within a potential window of 1 V to 4 V. The materials that make up the various layered elements of the electrochromic system must have an electrochemical stability range that is larger than the potential window required to obtain the coloring / bleaching phenomenon.

[0020] The "voltage stability range" of a material is the range of potentials to which the material can be exposed without undergoing oxidation or reduction reactions.

[0021] When a material is subjected to an electrochemical potential outside its stability range and is in the presence of corresponding ions, redox reactions occur.

[0022] In electrochromic systems, electrically conductive coatings are exposed to the electrochemical potential of the active materials they are in contact with. This means that the electrically conductive coatings of electrochromic devices must be stable within a potential window of 2V to 4V, or even 1V to 4V, relative to Li / Li+. Therefore, electrically conductive coatings must have an electrochemical stability range relative to the Li+ / Li pair, preferably 1V to 4V. The materials that make up these conductive coatings must not undergo redox reactions within this voltage range.

[0023] Known electrically conductive coatings comprise conductive functional layers based on transparent conductive oxides, such as indium tin or fluorine-doped tin layers, or metallic functional layers, in particular based on silver.

[0024] While electrically conductive coatings based on conductive oxide layers offer excellent electrochemical stability, they lack sufficient conductivity at high optical transmittances (>80%). As a result, non-uniform switching and / or slower switching speeds occur as the surface area of ​​the EC system increases. Finally, some applications, such as automotive applications, may require additional processing steps, such as hardening or bending. These additional steps are likely to alter the conductive oxide coating. To achieve the desired resistance, these coatings must be thick. However, such thick coatings are prone to cracking during heat treatment.

[0025] Conductive coatings with silver-based metal functional layers offer excellent electrical conductivity and high transparency. However, the low electrochemical stability of the silver functional layer limits the use of this type of conductive coating in electrochromic devices. In particular, silver-based conductive coatings undergo redox reactions in the range of 1 V to 4 V versus the Li / Li+ pair. At low potentials, these reactions, for silver-based coatings, result in the reduction of Ag material, the formation of metal alloys (e.g., LiAg), or the generation of reducing gas (hydrogen). At high potentials, these reactions result in the oxidation of Ag+ material, the formation of oxides (AgO), and / or the generation of oxidizing gas (oxygen). In the context of high-potential reactions, the "corrosion" of a material may also be referred to.

[0026] Known electrically conductive coatings of this type are: - optionally a first dielectric layer or a first dielectric coating, - a metal layer based on silver, optionally a blocking layer; - a second dielectric layer or coating, Includes.

[0027] Cyclic voltammograms were generated using a three-electrode configuration with a lithium metal counter electrode, a lithium metal reference electrode, and a working electrode containing the electrically conductive coating being tested to determine the voltage stability range of these electrically conductive coatings. The electrolyte was a LiClO4 / PC solution. The working electrode had a 2 mm glass substrate coated with a known silver-based electrically conductive coating, with the sequence (SiN / SnZnO / Al-doped ZnO / Ag) starting from the substrate. Voltammograms were acquired over a potential window of 2 to 4 V vs. Li / Li+ at a scan rate of 2 mV / s.

[0028] No oxidation reaction is observed between 2 V and 3.4 V. A slight increase in current density is observed near 3.4 V vs. Li / Li+, followed by a sharp increase near 3.7 V vs. Li / Li+. This sharp increase is due to the metallic Ag being converted to Ag +This is due to the fact that the conductive coatings are oxidized to ions that dissolve in the electrolyte. This means that such conductive coatings cannot be used in electrochromic devices unless the available contrast of the EC device is limited by imposing a potential below 3.7 V. In this case, complete coloring or bleaching is not achieved. Summary of the Invention [Problem to be solved by the invention]

[0029] To take advantage of the improved optical and conductive properties of silver-based electrically conductive coatings in electrochromic devices, there is a need to extend the range of their electrochemical stability.

[0030] The present invention relates to electrically conductive coatings having a silver-based metallic functional layer with improved electrochemical stability. The coatings of the present invention are particularly suitable for use in electrochromic devices. [Means for solving the problem]

[0031] Applicants have discovered that the use of certain blocking layers in combination with thick conductive oxides improves electrochemical stability, particularly around 3.7 V vs. Li / Li. This improved electrochemical stability makes drug-based conductive coatings suitable for EC applications.

[0032] The present invention relates to a material having a substrate that, starting from the substrate, is coated with a first conductive coating comprising: - a first dielectric coating, - a metallic functional layer based on silver, a blocking layer located above and in direct contact with the silver-based metallic functional layer, said blocking layer being selected from metal layers of one or more elements selected from nickel and chromium, such as Ni, Cr, NiCr, and metal nitride layers of one or more elements selected from titanium, nickel, and chromium, such as NiN, CrN, NiCrN, TiN, a second dielectric coating having at least one conductive oxide layer, the total thickness of which is greater than 40 nm, preferably greater than 50 nm.

[0033] The present invention increases the stability range of silver-based electrically conductive coatings to above 3.7 V vs. Li / Li+.

[0034] The present invention also relates to a conductive coating, which comprises a metallic functional layer, preferably transparent, based on silver, and which is electrochemically stable in a potential window of 2-4 V vs. Li / Li+. - a metallic functional layer based on silver, a blocking layer located above and in direct contact with the silver-based metallic functional layer, said blocking layer being selected from metal layers of one or more elements selected from nickel and chromium, such as Ni, Cr, NiCr, and metal nitride layers of one or more elements selected from titanium, nickel, and chromium, such as NiN, CrN, NiCrN, TiN, and the like.

[0035] This particular coating structure makes it possible to obtain a transparent electrically conductive coating with electrochemical resistance that is compatible with EC systems, while at the same time providing high electrical conductivity properties.

[0036] The present invention also relates to materials having one or more of the following properties: The blocking layer has a thickness of 0.1 to 5.0 nm. the blocking layer is selected from a titanium nitride layer, a nickel-based metal layer, and / or a chromium-based metal layer; the blocking layer is selected from nickel-based metal layers containing at least 20% by weight of nickel relative to the weight of the nickel-based metal layer; the second dielectric coating comprises a conductive oxide layer selected from tin-indium mixed oxide or zinc oxide doped with aluminum and / or gallium; the second dielectric coating comprises a conductive oxide layer based on zinc oxide doped with aluminum, with a thickness of more than 50 nm; the first dielectric coating comprises at least one crystallized dielectric layer, in particular based on zinc oxide, optionally doped with at least one other element, such as aluminium; the first dielectric coating comprises a layer based on nitrides or oxynitrides of aluminum and / or zirconium silicon and / or a layer based on zinc oxide and tin; The substrate is made of glass, in particular soda-lime-silica glass, or a polymeric organic material. the material further comprises a first active layer comprising an electrochromic material located in contact with the electrically conductive coating. the material further comprises an electrolyte layer located in contact with the first active layer comprising the electrochromic material, preferably the electrolyte being a lithium ion conducting electrolyte. the material further comprises a second active layer in contact with the electrolyte layer. the material further comprises a second electrically conductive coating located in contact with the electrolyte layer.

[0037] The present invention also relates to an electrochromic system comprising: - the material according to the invention. a first active layer comprising an electrochromic material; - electrolyte layer, a second active layer, and - a second transparent electrically conductive coating, - Optionally a substrate.

[0038] The electrochromic material of the active layer can be based on inorganic materials, such as tungsten oxide, nickel oxide, iridium oxide, cerium oxide, etc., or organic materials, such as electronically conducting polymers, such as polyaniline or (poly(3,4-ethylenedioxythiophene) (PEDOT)), or Prussian blue. These materials can insert cations, in particular protons or lithium ions.

[0039] The electrochromic material of the first active layer may be based on an oxide of an element selected from tungsten, nickel, iridium, chromium, iron, cobalt or rhodium, or a mixed oxide of at least two of these elements, in particular a mixed oxide of nickel and tungsten. It is preferably based on tungsten oxide.

[0040] The electrochromic material of the second active layer or counter electrode is preferably based on an oxide of an element selected from tungsten, nickel, iridium, chromium, iron, cobalt or rhodium, or on a mixed oxide of at least two of these elements, in particular a mixed oxide of nickel and tungsten. It is preferably based on nickel oxide or iridium oxide (anodic electrochromic material).

[0041] If the electrochromic material of the first active layer is tungsten oxide, i.e., a cathodic electrochromic material whose colored state corresponds to the most reduced state, then an anodic electrochromic material based on, for example, nickel or iridium oxide can be used for the counter electrode, in particular a layer of vanadium-tungsten mixed oxide or nickel-tungsten mixed oxide.

[0042] The thickness of the active layer is generally 50 nm to 600 nm, particularly 150 nm to 250 nm.

[0043] The thickness of the electrolyte layer can be 1 nm to 1 mm. When the electrolyte layer is made of an inorganic material, its thickness is preferably 1 to 300 nm, 1 to 50 nm, or 1 to 10 nm. When the electrolyte layer is made of a polymer material, its thickness is preferably 100 to 800 μm, or 100 to 500 μm.

[0044] The two electrically conductive coatings need to be connected to their respective power connectors, such as bus bars and wires, which are each brought into contact with the transparent conductive coating to provide the appropriate power supply.

[0045] The present invention also relates to an electrochromic system having two substrates held together by a frame. [Brief explanation of the drawings]

[0046] [Figure 1] FIG. 1 shows voltammetric cycles based on a three-electrode configuration with a lithium metal counter electrode, a lithium metal reference electrode, and working electrodes with various electrically conductive coatings (Rev. 1, Rev. 2, and Rev. 3).

[0047] [Figure 2] FIG. 2 shows voltammetric cycles based on a three-electrode configuration with a lithium metal counter electrode, a lithium metal reference electrode, and working electrodes with various electrically conductive coatings (Rev. 3, Rev. 4, and Rev. 5).

[0048] [Figure 3] FIG. 3 shows voltammetric cycles based on a three-electrode configuration with a lithium metal counter electrode, a lithium metal reference electrode, and working electrodes with various electrically conductive coatings (Rev. 1, Rev. 6, and Rev. 7).

[0049] [Figure 4]FIG. 4 shows voltammetric cycles based on a three-electrode configuration with a lithium metal counter electrode, a lithium metal reference electrode, and working electrodes with various electrically conductive coatings (Rev. 1, Rev. 6, and Rev. 7). DETAILED DESCRIPTION OF THE INVENTION

[0050] Throughout this specification, the substrate according to the invention is assumed to be horizontally placed. The electrically conductive coating is deposited above the substrate. The meaning of the expressions "above" and "below", "below" and "upper" shall be considered in this orientation. Unless otherwise specified, the expressions "above" and "below" do not necessarily mean that two layers and / or coatings are arranged in contact with each other. When it is specified that a layer is deposited "in contact" with another layer or coating, this means that one or more layers cannot be inserted between these two layers (or layer and coating).

[0051] All optical properties presented herein are obtained according to the principles and methods described in European Standard EN 410 for the measurement of the optical and solar properties of glazing used in the building industry.

[0052] The preferred properties described in the remainder of the description are applicable both to the material according to the invention and, where appropriate, to the glazing or system according to the invention.

[0053] The electrically conductive coating is deposited by magnetic field assisted cathode sputtering (magnetron method). According to this advantageous embodiment, all layers of the coating are deposited by magnetic field assisted cathode sputtering.

[0054] Unless otherwise stated, thicknesses referred to herein are physical thicknesses.

[0055] The present invention is suitable for single-layer silver-based functional coatings. The solution is also suitable for multi-layer silver-based functional coatings, especially those with two or three functional layers. The coating has at least one or only one silver-based metal functional layer.

[0056] The silver-based metal functional layer comprises at least 95.0 wt. %, preferably at least 96.5 wt. %, more preferably at least 98.0 wt. % silver, based on the weight of the functional layer, before or after heat treatment.

[0057] Preferably, the silver-based metal functional layer before heat treatment contains less than 1.0 wt. % of metals other than silver, based on the weight of the silver-based metal functional layer.

[0058] The term "metal layer" refers to a layer having less than 30%, less than 20%, or less than 10% oxygen and / or nitrogen in atomic percent within the layer. It has.

[0059] The purpose of the blocking layer is to improve the electrochemical properties of the silver layer.

[0060] When these blocking layers are deposited in the form of metals or nitrides, they may be partially or completely oxidized, depending on their thickness and the nature of the layers surrounding them, for example, during the deposition of a subsequent layer or by oxidation in contact with an underlying layer.

[0061] Advantageously, the blocking layer is a nickel-based metallic layer, which comprises at least 20 wt.%, at least 30 wt.%, at least 40 wt.%, at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, at least 96 wt.%, at least 97 wt.%, at least 98 wt.%, at least 99 wt.%, or 100 wt.% nickel, based on the weight of the nickel-based metallic layer (before heat treatment).

[0062] The nickel-based metallic layer may be selected from: - a metal layer of nickel, - a doped nickel metal layer, - Metal layer based on nickel alloy.

[0063] The metallic layer based on a nickel alloy may be based on a nickel-chromium alloy.

[0064] The blocking layer may also advantageously be a titanium nitride layer.

[0065] Each blocking layer has a thickness of 0.1 to 5.0 nm. The thicknesses of these blocking layers are: at least 0.1 nm, at least 0.2 nm, at least 0.5 nm, and / or Maximum 5.0nm, Maximum 4.0nm, Maximum 3.0nm, or Maximum 2.0nm, It is possible.

[0066] The electrically conductive coating has at least one functional layer and at least two dielectric coatings with at least one dielectric layer, whereby each functional layer is disposed between two dielectric coatings.

[0067] A "dielectric coating" in the sense of the present invention should be understood to mean that there may be one or several layers of different materials within the coating. A "dielectric coating" according to the present invention comprises mainly dielectric layers. However, according to the present invention, these layers may also comprise layers of another nature, in particular absorbing layers, such as absorbing metal layers.

[0068] "Identical" dielectric coatings are considered to be those located on: - between the substrate and the first functional layer, between each silver-based metal functional layer, - Above the last functional layer (farthest from the substrate).

[0069] A "dielectric layer" in the sense of the present invention should be understood to mean that the material is "non-metallic", i.e. not metallic, by its nature. In the context of the present invention, this term refers to a material having an n / k ratio of 5 or greater over the entire visible wavelength range (380 nm to 780 nm). n refers to the real part of the refractive index of the material at a given wavelength, and k represents the imaginary part of the refractive index at a given wavelength: the n / k ratio is calculated at a given wavelength where n and k are identical.

[0070] The thickness of the dielectric coating corresponds to the sum of the thicknesses of the layers that make it up.

[0071] The coating has a thickness of more than 15 nm, preferably between 15 and 200 nm.

[0072] The dielectric layers of the coating exhibit the following properties, alone or in combination: They are deposited by magnetic field assisted sputtering. They are selected from oxides or nitrides of one or more elements selected from titanium, silicon, aluminum, zirconium, tin, indium and zinc. They have a thickness of more than 2 nm, preferably between 2 and 100 nm.

[0073] The dielectric coating above the silver-based metallic functional layer requires that the electrically conductive coating be sufficiently conductive to maintain its electrode function.

[0074] The dielectric coating above the silver-based metallic functional layer comprises at least one conductive oxide layer selected from mixed oxides of tin and indium, tin-doped indium oxide (ITO, "indium tin oxide"), doped zinc oxide, such as aluminum-doped zinc oxide (AZO) and / or gallium-doped zinc oxide, doped ruthenium oxide, and fluorine-doped tin oxide (SnO2:F).

[0075] Preferably, indium tin oxide (ITO) or zinc oxide doped with aluminum and / or gallium is used.

[0076] The sum of the thicknesses of all conductive oxide layers in the dielectric coating directly above the silver-based functional layer is greater than 50 nm, or greater than 60 nm.

[0077] The total thickness of all conductive oxide layers in the dielectric coating directly above the silver-based functional layer is less than 150 nm, less than 100 nm, or less than 80 nm.

[0078] Preferably, the dielectric coating directly above the silver-based functional layer comprises at least one conductive oxide layer that is more than 50 nm or more than 60 nm thick.

[0079] Preferably, the dielectric coating directly above the silver-based functional layer comprises at least one conductive oxide layer based on aluminum-doped zinc oxide that is more than 50 nm or more than 60 nm thick. The combination of the blocking layer according to the invention with a thick conductive oxide layer based on doped zinc oxide provides the best results in terms of electrochemical stability.

[0080] According to one embodiment, the dielectric coating may have at least two layers: a layer of aluminum doped zinc oxide and a layer of mixed indium tin oxide (ITO).

[0081] According to the present invention, indium tin oxide (ITO) is a mixed oxide or mixture obtained from indium (III) oxide (In2O3) and tin (IV) oxide (SnO2), preferably with 70-95% by weight of the former oxide and 5-20% by weight of the latter oxide. A typical mass ratio is about 10% SnO2 to about 90% In2O3.

[0082] According to the present invention, a conductive oxide layer based on zinc oxide may contain at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% by weight of zinc, compared to the weight of all elements forming the zinc oxide layer, excluding oxygen and nitrogen. To be sufficiently conductive, the zinc oxide layer is doped with at least one other element, known as a "doping element." Thus, the zinc oxide layer may contain one or more doping elements selected from aluminum, titanium, niobium, zirconium, magnesium, copper, silver, gold, silicon, molybdenum, nickel, chromium, platinum, indium, tin, and hafnium, preferably aluminum.

[0083] Conductive layers based on doped zinc oxide may include: at least 1%, at least 2%, or at least 5% by weight, and / or - maximum 15% by weight or 10% by weight, doping elements relative to the total weight of all elements forming the zinc oxide based layer, excluding oxygen and nitrogen.

[0084] The dielectric coating underneath the silver-based metal functional layer does not have to be conductive. Advantageously, it can have a crystallization layer, also known as a stabilization layer or wetting layer. A stabilization layer is understood to mean a layer made of a material capable of stabilizing the interface with the functional layer. These layers are generally based on zinc oxide.

[0085] The zinc oxide based layer comprises at least 50% by weight, at least 60% by weight, at least 70% by weight, at least 80% by weight, at least 90% by weight, at least 95% by weight, at least 96% by weight, at least 97% by weight, at least 98% by weight, at least 99% by weight or 100% by weight of zinc compared to the total weight of all elements forming the zinc oxide based layer other than oxygen and nitrogen.

[0086] In order to be correctly crystallized by magnetron sputtering, a layer based on zinc oxide advantageously contains at least 80% by weight, or even 90% by weight, of zinc relative to the total weight of all elements constituting the zinc oxide layer, excluding oxygen and nitrogen.

[0087] The zinc oxide based layer may contain one or more elements selected from aluminum, titanium, niobium, zirconium, magnesium, copper, silver, gold, silicon, molybdenum, nickel, chromium, platinum, indium, tin and hafnium, preferably aluminum.

[0088] The zinc oxide based layer may optionally be doped with at least one other element, such as aluminum.

[0089] The zinc oxide based layer comprises, in order of increasing preference, at least 80% by weight, at least 90% by weight, at least 95% by weight, at least 98% by weight, at least 100% by weight of oxygen relative to the total weight of oxygen and nitrogen.

[0090] Preferably, the dielectric coating located directly below the silver-based metallic functional layer comprises at least one crystallized dielectric layer, in particular based on zinc oxide, optionally doped with at least one other element, such as aluminum.

[0091] These zinc oxide layers have the following thicknesses: at least 1.0 nm, at least 2.0 nm, at least 3.0 nm, at least 4.0 nm, at least 5.0 nm, and / or Maximum 25nm, maximum 10nm, or maximum 8.0nm.

[0092] Preferably, the dielectric coating directly below the silver-based functional metal layer comprises at least one dielectric layer with a barrier function. A dielectric layer with a barrier function (hereinafter barrier layer) is understood to mean a layer made of a material that, at high temperatures, forms a barrier against the diffusion of oxygen and water originating from the surrounding atmosphere or from the transparent substrate towards the functional layer. Such a dielectric layer may be selected from the following layers: based on compounds of silicon and / or aluminum and / or zirconium, optionally doped with at least one other element, selected from oxides such as SiO2, nitrides such as silicon nitride Si3N4 and aluminum nitride AlN, and oxynitrides SiOxNy; - based on zinc tin oxide, - Based on titanium dioxide.

[0093] Preferably, the first dielectric coating has at least one dielectric layer based on: nitrides or oxynitrides of aluminum and / or silicon and / or zirconium, or - mixed oxides of zinc and tin, or - Titanium dioxide.

[0094] Preferably, the first dielectric coating comprises: layers based on nitrides or oxynitrides of aluminum and / or silicon and / or zirconium, and / or - layers based on mixed oxides of zinc and tin, and / or - a layer based on nitrides or oxynitrides of aluminum and / or silicon and / or zirconium and a dielectric layer based on a mixed oxide of zinc and tin located above and preferably in contact with the layer based on nitrides or oxynitrides of aluminum and / or silicon and / or zirconium.

[0095] The zinc tin oxide based layer is located below and preferably in contact with the oxide based layer.

[0096] These dielectric layers having a barrier function have the following thicknesses in order of increasing priority: - 40 nm or less, 30 nm or less, 25 nm or less, and / or - 5nm or more, 10nm or more, or 15nm or more.

[0097] The electrically conductive substrate coated with the coating, or the coating alone, may not have been subjected to a heat treatment. The present invention relates to non-heat treated materials or heat treated materials.

[0098] The electrically conductive coating may not have been subjected to a heat treatment at a temperature above 500°C, preferably above 300°C.

[0099] The coating may need to be subjected to a heat treatment at a temperature above 300°C, preferably above 500°C. In this case, the heat treatment is selected from annealing, for example by "rapid thermal processing" annealing, such as laser or flash lamp annealing, tempering, and / or bending. Rapid thermal processing annealing is described, for example, in WO 2008 / 096089. The heat treatment temperature (at the time of coating) is above 300°C, preferably above 400°C, and more preferably above 500°C.

[0100] The substrate coated with the coating can be bent glass or tempered glass.

[0101] The transparent substrate according to the invention is preferably made of a rigid inorganic material, such as glass, or organic and based on (or made of) a polymer.

[0102] The organic transparent substrate according to the invention may also be made of a polymer and may be rigid or flexible. Examples of suitable polymers according to the invention include, in particular: - polyethylene, - polyesters, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), etc.; - polyacrylates, such as polymethyl methacrylate (PMMA); - polycarbonate; - polyurethane; - polyamide; - polyimide; - fluorinated polymers, such as fluorinated esters, such as ethylene-tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene (ECTFE), fluorinated ethylene-propylene copolymers (FEP), etc.; photocrosslinkable and / or photopolymerizable resins, such as thiolenes, polyurethanes, urethane acrylates, polyester acrylates, etc., and - Polythiourea.

[0103] The substrate is preferably a sheet of glass or of glass ceramic.

[0104] The substrate is preferably transparent, colorless (in which case it is clear glass or extra clear glass), or colored, for example blue, gray, or bronze. The glass is preferably of the soda-lime-silica type, but it may also be of the borosilicate or aluminoborosilicate type.

[0105] According to a preferred embodiment, the substrate is made of glass, in particular soda-lime-silica glass, or a polymeric organic material.

[0106] Advantageously, the substrate has at least one dimension of 1 m or more, or even 2 m or more, or even 3 m or more.

[0107] The thickness of the substrate is generally in the range of 0.05 mm to 19 mm. When the substrate is inorganic, its thickness is preferably 0.7 mm to 9 mm, particularly 2 mm to 8 mm, or even 4 mm to 6 mm. The substrate may be flat or curved, or even flexible. When the substrate is organic, its thickness is preferably 1 mm to 2 mm. [Example]

[0108] I. Electrically conductive coating

[0109] The electrically conductive coating was sputtered onto a transparent glass substrate, which was a 2.1 mm aluminosilicate glass substrate.

[0110] The functional layer (F) is a silver-based metal layer.

[0111] The dielectric coating has the following layers: - coatings based on silicon nitride, - zinc tin oxide layer, - aluminum-doped zinc layer, - Indium tin layer.

[0112] The blocking layer is selected from titanium, titanium nitride, nickel chromium, and zinc layers.

[0113] The deposition conditions of the layers, deposited by sputtering (“magnetron cathode” sputtering), are summarized in Table 1. [Table 1]

[0114] Table 2 lists the materials for each layer or coating that forms the coating as a function of position relative to the substrate carrying the stack (last row at the bottom of the table). [Table 2]

[0115] The initial dielectric coating has a sequence of SiN / SnZnO / ZnO to prevent diffusion of species from the substrate, reduce surface roughness, and optimize silver quality.

[0116] The coating is not heat treated at high temperatures.

[0117] II. Determination of electrochemical properties

[0118] Voltammetric cycles were performed to determine the electrochemical properties of the conductive coatings relative to mobile electrolyte species, such as Li / Li+. To achieve this, the current response resulting from a continuous change in the potential of the conductive coating (used as the working electrode) where the electrochemical reaction under study occurs is measured.

[0119] The figure shows voltammetric cycles based on a three-electrode configuration with a lithium metal counter electrode, a lithium metal reference electrode, and a working electrode with various electrically conductive coatings. The electrolyte is a LiClO4 / PC solution.

[0120] Voltammograms were acquired in a potential window of 2–4 V vs. Li / Li+ at a scan rate of 2 mV / s.

[0121] 1. The nature of the dielectric layer of the upper dielectric coating

[0122] Electrically conductive coatings 1, 2, and 3 (Rev. 1, Rev. 2, and Rev. 3) differ in the selection of one or more conductive oxide layers that make up the upper dielectric coating.

[0123] The electrically conductive coating tested in Figure 1 was not heat treated. In this graph, degradation of the coating is observed, along with oxidation and reduction peaks and an increase in current above 3.4 V vs. Li / Li+.

[0124] However, this phenomenon is less pronounced when using conductive oxide layers based on aluminum-doped zinc oxide. This is reflected in the lower peak of Coating 1 (Rev. 1) than that of Coating 2 (Rev. 2) or Coating 3 (Rev. 3). Therefore, the electrically conductive coating of the present invention preferably has at least one aluminum-doped zinc oxide layer with a thickness of more than 40 nm or more than 50 nm.

[0125] 2. Properties of the blocking layer

[0126] 1. No heat treatment

[0127] Coatings 4 and 5 (Rev. 4 and Rev. 5) differ from Coating 3 (Rev. 3) in the nature of the blocking layer (TiN and NiCr vs. Ti, respectively). Figure 2 shows the voltammogram cycles of these three coatings without heat treatment.

[0128] Changing the metal blocking layer from Ti to TiN or NiCr has a strong effect on the electrochemical window of silver. The current rise above 3.4 V vs. Li / Li+ is significantly reduced, and the oxidation or reduction peaks around 3.6–3.7 V vs. Li / Li+ are no longer observed. This electrode coating is compatible with EC devices operating in the range of 2–4 V vs. Li / Li+.

[0129] The NiCr and TiN layers act as an effective shield against any possible degradation of the silver layer during subsequent layer deposition (cathode sputtering), high temperature annealing, and / or subsequent electrochemical reactions.

[0130] Coating 6, Coating 7, and Coating 1 (Rev. 6, Rev. 7, and Rev. 1) differ in the nature of the blocking layer (NiCr, Zn, and Ti, respectively). Figure 3 shows the voltammogram cycles for these three coatings.

[0131] No heat treatment was performed.

[0132] The presence of a blocking metal layer based on zinc or titanium near the silver layer does not have any beneficial effect. The presence of redox peaks indicates electrode degradation.

[0133] Coating 6 (Rev. 6) has good electrochemical stability: there is almost no current increase above 3.4 V and no redox peaks.

[0134] The present invention allows silver-based coatings to be used in high contrast electrochromic devices operating in the range of 2-4 V vs. Li / Li+.

[0135] 2. After heat treatment

[0136] After heat treatment at 600° C. for 8 minutes, redox peaks are observed for Coating 1, Coating 7, and Coating 6 (Rev. 1, Rev. 7, and Rev. 6). Figure 4 shows the voltammetric cycles of these three coatings after heat treatment.

[0137] This phenomenon is particularly pronounced in the case of Coating 7 (Rev. 7), which has a metallic zinc blocking layer. An increase in current above 3.4 V is observed, as well as redox peaks at 3.6 V and 3.7 V. After heat treatment, the presence of the metallic zinc layer alone does not improve the electrochemical stability of silver.

[0138] For coating 6 (Rev. 6) with a blocking layer based on NiCr, the favorable effect of this layer becomes relatively weaker in the case of heat treatment.

Claims

1. A material having a substrate coated with a first coating, said first coating comprising, starting from said substrate: a first dielectric coating, - metallic functional layers based on silver, a blocking layer located above and in direct contact with said silver-based metallic functional layer, said blocking layer being selected from metal layers of one or more elements selected from nickel and chromium, such as Ni, Cr, NiCr, and metal nitride layers of one or more elements selected from titanium, nickel, and chromium, such as NiN, CrN, NiCrN, TiN, a second dielectric coating comprising at least one conductive oxide layer, the total thickness of said conductive oxide layers within said second dielectric coating being greater than 40 nm; A material having

2. The material of claim 1 , wherein the blocking layer has a thickness of 0.1 to 5.0 nm.

3. 3. The material according to claim 1 or 2, wherein the blocking layer is selected from a titanium nitride layer, a nickel-based metal layer, and / or a chromium-based metal layer.

4. 4. The material of claim 1, wherein the second dielectric coating comprises a conductive oxide layer selected from mixed oxides of tin and indium, indium tin oxide, doped zinc oxide, doped ruthenium oxide, and fluorine-doped tin oxide.

5. 5. The material according to claim 1, wherein the second dielectric coating comprises a conductive oxide layer selected from a mixed oxide of tin and indium, or zinc oxide doped with aluminium and / or gallium.

6. The material according to any one of claims 1 to 5, wherein the second dielectric coating comprises a conductive oxide layer based on aluminium-doped zinc oxide having a thickness of more than 50 nm.

7. 7. The material according to claim 1, wherein the first dielectric coating comprises at least one crystallized dielectric layer, in particular based on zinc oxide, optionally doped with at least one other element, such as aluminum.

8. 8. The material according to claim 7, wherein the crystallized dielectric layer, in particular based on zinc oxide, has a thickness of 2 to 15 nm.

9. The first dielectric coating is: aluminium and / or zirconium silicon nitrides or oxynitrides, and / or - layers based on zinc tin oxide, The material according to any one of claims 1 to 8, having

10. The material according to any one of the preceding claims, wherein the substrate is made of glass, in particular soda-lime-silica glass, or a polymeric organic material.

11. 1. An electrochromic system comprising: - a material having a substrate coated with a first coating, said first coating comprising, starting from said substrate: a first dielectric coating, - metallic functional layers based on silver, a blocking layer located above and in direct contact with said silver-based metallic functional layer, said blocking layer being selected from metal layers of one or more elements selected from nickel and chromium, such as Ni, Cr, NiCr, and metal nitride layers of one or more elements selected from titanium, nickel, and chromium, such as NiN, CrN, NiCrN, TiN, a second dielectric coating comprising at least one conductive oxide layer, the total thickness of said conductive oxide layers being greater than 40 nm; a material having a first active layer comprising an electrochromic material; an electrolyte layer; a second active layer, a second transparent electrically conductive coating, optionally a substrate, An electrochromic system comprising:

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