ELECTROCHROME GLAZING

Abstract

The invention relates to a material comprising a substrate coated with a first conductive coating comprising, starting from the substrate: - a first dielectric coating, - a silver-based metallic functional layer, - a blocking layer located immediately in contact with a silver-based metallic functional layer, - at least one zinc-based metallic layer, located above or below this silver-based metallic functional layer, directly in contact with or separated by one or more layers whose total thickness is less than or equal to 20 nm, - a second dielectric coating comprising at least one conductive oxide layer, the sum of the thicknesses of the conductive oxide layers in the second dielectric coating being greater than 30 nm.

Description

Title of the invention: ELECTROCHROME GLAZING

[0001] The present invention relates to the field of electrochromic (EC) glazing. The invention relates in particular to an electroconductive coating for an electrochromic device comprising a silver-based metallic functional layer having improved electrochemical properties.

[0002] Electrochromic devices, and in particular electrochromic glazing, are systems capable of modulating their optical response, in the visible or in the infrared, under the action of an electrical voltage, thus making it possible to obtain electrically controlled coatings that are easily adjustable.

[0003] Electrochromic devices include, in a known manner, an electrochromic system comprising a succession of at least five layered elements essential to the operation of the device, that is, to the reversible color change following the application of an appropriate electrical supply. These five layered elements are as follows: - a first transparent electroconductive coating, - a first active layer acting as an electrode, - a layer of electrolyte, - a second active layer acting as a counter electrode, and - a second transparent electroconductive coating. At least one active layer is based on an electrochromic material. These five layered elements are generally in contact with one or two transparent substrate(s).

[0004] Electrochromic systems fall into three categories: - the inorganic technology known as "all-solid", - the so-called "hybrid" technology, - the so-called "all-polymer" technology.

[0005] In all-solid electrochromic systems, all layers are made of inorganic solid materials. These systems may comprise a single substrate. Examples of all-solid EC systems are described in patent applications EP-867 752, EP-831 360, WO 00 / 57243 and WO 00 / 71777.

[0006] Hybrid electrochromic systems comprise inorganic active layers framing an electrolyte layer based on an ionically conductive polymer. These systems traditionally comprise two substrates framing the electrochromic system. Examples of hybrid EC systems are described in patent applications EP-382,623, EP-518,754, and EP-532,408.

[0007] In "all-polymer" electrochromic systems, the active layers and the layer electrolytes are polymer-based.

[0008] The phenomenon of colouring / decolouring in the visible range or of modifications of optical properties in general, results from a transfer of charge (ions / electrons) between the two active layers.

[0009] An active layer based on an electrochromic material is capable of reversibly inserting ions. When the ions migrate to this layer, its optical properties change, and it reversibly transitions from a colorless state to a colored state. The other active layer may also be based on an electrochromic material.

[0010] Inorganic electrochromic materials are predominantly transition metal oxides, grouped into two families: cathodic color-changing oxides, such as tungsten oxide (WO3), which exhibit color in the reduced state, and anodic color-changing oxides, such as iridium oxide (IrOx) and nickel oxide (NiOx), which are colored in the oxidized state. Pairs of cathodic and anodic electrochromic materials are generally chosen, for example, a cathodic material that colors in the inserted state in association with an anodic material that is colorless in the inserted state.

[0011] The electrolyte layer must exhibit good ionic conductivity and be electronically insulating. The electrolytes of the electrochromic system ensure the passage of mobile ions within their electrochemical stability range. In theory, all monovalent ions, such as H+, Li+, Na+, K+, Ag+, divalent ions such as Zn2+, and trivalent ions such as Al3+ can be used. Lithium, alkali, or hydrogen salts are particularly suitable.

[0012] By way of example, for an active layer of tungsten oxide (WO3) in contact with a lithium ion-conducting electrolyte layer, there is a transfer of Li+ ions between the electrodes when a voltage is applied. The following electrochemical reaction is observed at the cathode: W6 + O2 3 (transparent) + x Li+ + xe → LUW^isW^ XO2 3 (blue).

[0013] The voltage ranges that provide the best contrast between the colored and decolorized states can be determined by voltammetry. Voltammetric cycles or curves, or voltamgrams (j = f(V)), consist of tracking the variation of the current density j over the swept potential range. The study of current density variations is significant in understanding the electrochemical behavior of materials. The color potentials (Vcoloration) and decolorization potentials (Vdecoloration) of the material, corresponding to oxidation reactions in the anodic part (j > 0) or reduction reactions in the cathodic part of the curve (j < 0), as well as the stability ranges, can be directly deduced from these curves.

[0014] If we consider an electrochromic device comprising an active layer with co cathodic loration based on tungsten oxide and an electrolyte layer including lithium ions, a coloured state is observed at 2.3 V and a colourless state at 3.2 V (vs Li / Li+).

[0015] If we consider an electrochromic device comprising an active layer with anodic coloring based on nickel oxide and an electrolyte layer comprising lithium ions, the oxidation potential associated with the disinsertion of lithium ions is approximately 4 V while the decolorization voltage can be adjusted by doping the nickel oxide between IV and 2.5 V.

[0016] If we consider the known all-polymer EC systems comprising an electrolyte layer comprising lithium ions, the voltage range between a less transparent state and a more transparent state is between 2V and 4V vs Li / Li+.

[0017] Therefore, for these EC systems, the reactions enabling coloring and decolorization occur within a potential window between IV and 4V. The materials constituting the various layer elements of the electrochromic system must have electrochemical stability ranges exceeding the potential windows required to obtain the coloring / decolorizing phenomena.

[0018] The term "voltage stability range" of a material means the potential range to which a material can be exposed without undergoing an oxidation or reduction reaction.

[0019] When a material is subjected to an electrochemical potential outside its stability range and in the presence of the corresponding ions, an oxidation-reduction reaction occurs.

[0020] In the case of electrochromic systems, the electroconductive coatings are exposed to the electrochemical potentials of the active materials with which they are in contact. This means that the electroconductive coatings of the electrochromic device must be stable in the potential range of 2 V to 4 V, or even from IV to 4 V, with respect to Li / Li+. The electroconductive coatings must therefore exhibit an electrochemical stability range relative to the Li+ / Li couple preferably between IV and 4 V. The constituent materials of these conductive coatings must not undergo redox reactions within this voltage range.

[0021] Known electroconductive coatings include conductive functional layers based on transparent conductive oxide such as indium and tin layers or fluorine-doped tin layers or metallic functional layers, particularly silver-based.

[0022] Electroconductive coatings based on a conductive oxide layer, although exhibiting excellent electrochemical stability, do not possess sufficient conductive properties at high light transmission (>80%). This results in inhomogeneous switching and / or a switching speed that decreases when the The surface area of ​​the EC system increases. Finally, in certain applications, such as automotive applications, additional processing steps like quenching or bending are sometimes necessary. These additional steps can alter conductive oxide-based coatings. Indeed, these coatings must be thick to achieve the desired resistivity values. However, these thick coatings are susceptible to cracking during heat treatment.

[0023] Conductive coatings comprising a silver-based metallic functional layer exhibit superior 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. Silver-based conductive coatings undergo redox reactions with respect to the Li / Li+ couple in the 1V-4V range. At low potentials, these reactions lead to the reduction of the Ag material, the formation of a metallic alloy (such as LiAg), or the production of reduced gas (dihydrogen) for a silver-based layer. At high potentials, these reactions lead to the oxidation of the Ag+ material, the formation of an oxide (AgO), and / or the production of oxidized gas (dioxygen). In the context of high-potential reactions, one can also speak of "corrosion" of the materials.

[0024] Known electroconductive coatings of this type include: - possibly a first dielectric layer or first dielectric coating, - a silver-based metallic layer, - possibly a blocking layer, - a second dielectric layer or dielectric coating.

[0025] Cyclic voltamograms were performed to determine the voltage stability range of these electroconductive coatings using a three-electrode setup with a metallic lithium counter electrode, a metallic lithium reference electrode, and a working electrode comprising the electroconductive coating to be tested. The electrolyte is a LiClO4 / PC solution. The working electrode comprises a 2 mm glass substrate coated with a known silver-based electroconductive coating consisting, from the substrate, of the sequence (SiN / SnZnO / ZnO doped Al / Ag). The voltamogram was performed in the potential range of 2 to 4 V relative to Li / Li+ at a sweep rate of 2 mV / s.

[0026] No oxidation reaction is observed between 2 V and 3.4 V. A slight increase in current density is observed around 3.4 V vs. Li / Li+, followed by a sharp increase around 3.7 V vs. Li / Li+. This sharp increase is attributable to The oxidation of metallic Ag to Ag+ ions, which dissolve in the electrolyte, demonstrates that such conductive coatings cannot be used in electrochromic devices except by limiting the accessible contrast of the EC device by imposing potentials below 3.7 V. In this case, no complete decolorization or coloring is achieved.

[0027] In order to be able to benefit in electrochromic devices from the improved optical and conductive properties of silver-based electroconductive coatings, it is necessary to expand their electrochemical stability range.

[0028] The present invention relates to an electroconductive coating comprising a silver-based metallic functional layer exhibiting improved electrochemical stability. The coating of the invention is particularly suitable for use in electrochromic devices.

[0029] The applicant has discovered that the use of certain blocking layers in combination with a zinc- or indium-based metallic layer near the silver-based functional layer results in improved electrochemical stability, particularly around 3.7 V vs. Li / Li+. This improved electrochemical stability makes the use of the agent-based conductive coating compatible with EC applications.

[0030] The invention relates to a material comprising a substrate coated with a first conductive coating comprising, starting from the substrate:

[0031] - a first dielectric coating,

[0032] - a metallic functional layer comprising a silver base layer, - a blocking layer located immediately in contact with a functional silver-based metallic layer, selected from metallic layers based on a metal or metallic alloy, metallic nitride layers, metallic oxide layers and metallic oxynitride layers, of one or more elements selected from titanium, nickel, chromium, tantalum and niobium, aluminium oxide layers and silicon oxide layers,

[0033] - at least one metallic layer based on zinc or indium, located above or in beneath this functional silver-based metallic layer, either directly in contact or separated by one or more layers whose total thickness is less than or equal to 20 nm,

[0034] - preferably, a second dielectric coating comprising at least one conductive oxide layer, the sum of the thicknesses of the conductive oxide layers in the second dielectric coating is greater than 30 nm, preferably greater than 40 nm.

[0035] The invention makes it possible to increase the stability range of the silver-based electroconductive coating above 3.7 V compared to Li / Li+.

[0036] The invention also relates to a conductive coating comprising a metallic functional layer including a silver base layer, preferably transparent, electrochemically stable in the potential window of 2 to 4 V relative to Li / Li+. The conductive coating comprises:

[0037] - a metallic functional layer comprising a silver base layer, - a blocking layer located immediately in contact with a functional silver-based metallic layer,

[0038] - at least one zinc-based metallic layer, located above or below this functional silver-based metallic layer, directly in contact or separated by one or more layers whose total thickness is less than or equal to 20 nm.

[0039] The most advantageous properties of the invention are obtained after high-temperature heat treatment. The electroconductive coating or the material of the invention, i.e. the substrate coated with the electroconductive coating, preferably undergoes high-temperature heat treatment, i.e. at a temperature above 250°C, preferably above 300°C, 400°C or 500°C.

[0040] The blocking layers are intended to improve the electrochemical properties of the silver layers. The blocking layers are preferably deposited in metallic or nitrided form, based on one or more elements selected from nickel, iron, zirconium, titanium, and tungsten. These blocking layers are intended to protect the silver layer and to prevent the diffusion of ions from the active layer, such as Li+ ions.

[0041] Without being bound by any particular theory, it is likely that part of the zinc or metallic indium layer will alloy with the silver, especially during high-temperature heat treatment. The blocking layer allows this doping to be modulated.

[0042] Each of these layers contributes to improving the electrochemical stability of the silver-based metal layer. However, the combination of the blocking layer and the zinc layer leads to the best results in terms of high contrast for the final EC device and in terms of electrochemical stability for the electroconductive coating.

[0043] The zinc or metallic indium-based layer must be located near the silver layer. It may be located above, below, or on either side of the silver layer.

[0044] Thanks to this particular coating structure, it is possible to obtain a transparent conductive coating with electrochemical stability compatible with EC systems while having high electrical conductivity properties and high levels of light transmission, in particular above 60%, 70% or 80%.

[0045] The invention also relates to a material having the following characteristic(s): - the blocking layer has a thickness between 0.1 and 5.0 nm or between 0.5 and 2 mn, - the blocking layer is chosen from a titanium nitride layer, nickel and / or chromium-based metallic layers, nickel and / or chromium oxide layers, aluminum oxide layers, silicon oxide layers, - the blocking layer is chosen from nickel-based metallic layers comprising at least 20% nickel by mass relative to the mass of the nickel-based metallic layer, - the zinc- or indium-based metallic layer is separated from the silver-based functional metallic layer by at least one blocking layer, - the thickness of all layers separating the functional silver-based metallic layer from the zinc or indium-based metallic layer is less than or equal to 10 nm, - the metallic layer based on zinc or indium is located above the functional metallic layer based on silver, - the thickness of the zinc or indium-based metallic layer is between 0.2 and 10 nm, - zinc-based metallic layers comprise at least 20% zinc by mass relative to the mass of the zinc-based metallic layer, - the second dielectric coating comprises a conductive oxide layer selected from mixed tin and indium oxide or zinc oxide doped with aluminum and / or gallium, - the second dielectric coating comprises a conductive oxide layer based on aluminum-doped zinc oxide with a thickness greater than 50 nm, - the first dielectric coating comprises at least one crystalline dielectric layer, notably based on zinc oxide, possibly doped with at least one other element, such as aluminium, - the first dielectric coating comprises a layer based on aluminum and / or zirconium silicon nitride or oxynitride, and / or a layer based on zinc and tin oxide, - the stack has undergone heat treatment at a temperature above 300 °C, preferably 500 °C, at 550 °C or 600 °C, - The silver-based functional layer includes zinc, - the substrate is made of glass, particularly soda-lime silico-glass or polymeric organic matter, - the material further comprises a first active layer comprising a material electrochromic plate located in contact with the electroconductive coating, - the material further comprises an electrolyte layer located in contact with the first active layer comprising an electrochromic material, preferably the electrolyte is a lithium ionic conduction electrolyte, - the material further comprises a second active layer located in contact with the electrolyte layer, - the material further comprises a second electroconductive coating located in contact with the electrolyte layer.

[0046] The invention also relates to an electrochromic system comprising: - a material according to the invention comprising a first transparent electroconductive coating, - a first active layer comprising an electrochromic material, - an electrolyte layer, - a second active layer and - a second transparent electroconductive coating, - possibly a substrate.

[0047] The electrochromic material of the active layers may be based on a mineral material such as tungsten oxide, nickel oxide, iridium oxide, cerium oxide, or on an organic material such as electronically conductive polymers like polyaniline or poly(3,4-ethylenedioxythiophene) (PEDOT) or Prussian blue. These materials may incorporate cations, in particular protons or lithium ions.

[0048] 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, 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 tungsten oxide.

[0049] 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, 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).

[0050] 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, an anodic electrochromic material based on nickel or iridium oxide can, for example, be used for the counter electrode. This could, in particular, be a layer of mixed vanadium and tungsten oxide or mixed nickel and tungsten oxide.

[0051] The thickness of the active layers is generally between 50 nm and 600 nm, in particular between 150 nm and 250 nm.

[0052] The thickness of the electrolyte layer can be between 1 nm and 1 mm. When the electrolyte layer is made of an inorganic material, its thickness is preferably between 1 and 300 nm, between 1 and 50 nm, or between 1 and 10 nm. When the electrolyte layer is made of a polymeric material, its thickness is preferably between 100 and 800 pm or between 100 and 500 pm.

[0053] The two electroconductive coatings must be connected to respective power supply connectors. These connectors, for example busbar and wires, are respectively brought into contact with the electroconductive coatings to supply the appropriate power supply.

[0054] The invention also relates to an electrochromic system comprising two substrates made joined together by means of a chassis or frame.

[0055] Throughout this description, the substrate according to the invention is considered to be horizontally positioned. The electroconductive coating is deposited on top of the substrate. The meanings of the terms "above" and "below," and "lower" and "upper," are to be understood with respect to this orientation. Unless otherwise specified, the terms "above" and "below" do not necessarily mean that two layers and / or coatings are in contact with each other. When it is specified that a layer is deposited "in contact" with another layer or coating, this means that there cannot be one (or more) layer(s) interposed between these two layers (or layer and coating).

[0056] All the luminous characteristics described are obtained according to the principles and methods of the European standard EN 410 relating to the determination of the luminous and solar characteristics of glazing used in glass for construction.

[0057] The preferred characteristics that appear in the following description are applicable both to the material according to the invention and, where applicable, to the glazing or system according to the invention.

[0058] The electroconductive coating is deposited by magnetic field-assisted sputtering (magnetron process). According to this advantageous embodiment, all layers of the coating are deposited by magnetic field-assisted sputtering.

[0059] Unless otherwise stated, the thicknesses referred to in this document are physical thicknesses.

[0060] The present invention is suitable for single-layer functional silver-based coatings. The solution of the invention is also suitable for multi-layer functional silver-based coatings, in particular two- or three-layer functional coatings. The coating comprises at least one or a single functional silver-based metallic layer.

[0061] The silver-based functional metallic layer, before or after heat treatment, comprises at least 95.0%, preferably at least 96.5% and better still at least 98.0% by mass of silver relative to the mass of the functional layer.

[0062] Preferably, the silver-based functional metal layer before heat treatment comprises less than 1.0% by mass of metals other than silver relative to the mass of the silver-based functional metal layer.

[0063] After heat treatment, the functional silver-based metallic layer may include a proportion of zinc or indium. A measurement of the zinc or indium doping can be carried out, for example, by Castaing microprobe analysis (ElectroProbe MicroAnalyzer or EPMA) or by atom probe tomography.

[0064] The thickness of the silver-based functional layer is from 5 to 25 nm.

[0065] The zinc-based metal layer is located in a dielectric coating in contact with said silver-based functional metal layer. This means that the zinc-based metal layer is not separated from said silver-based functional metal layer by another silver-based functional metal layer.

[0066] The presence of a layer of metallic zinc or indium near the silver layer causes the migration of metallic zinc elements into the silver layer, particularly during heat treatment. The presence of a blocking layer in contact with the silver layer appears to slow the diffusion of metallic zinc or indium through the silver layer.

[0067] Consider the case where the zinc-based metallic layer is located above the silver layer. If metallic zinc elements diffuse at temperatures lower than the heat treatment temperature, in the absence of a blocking overlayer, they can easily pass through the silver layer without being sufficiently retained. Conversely, when a blocking overlayer is inserted between the silver and zinc layers, the blocking layer can act as a barrier and slow the diffusion of metallic zinc elements. This allows metallic zinc elements to be retained in the silver layer.

[0068] To a lesser extent, the use of a blocking underlayer also serves to prevent the diffusion of metallic zinc elements and to confine them near the silver layer. Configurations according to this embodiment can be advantageous.

[0069] Preferably, the blocking layer is located between the functional layer and the zinc- or indium-based metallic layer.

[0070] In the following paragraphs, zinc- or indium-based metallic coatings are defined as they are obtained during deposition, i.e., before heat treatment. Since heat treatment induces the migration of elements With metallic zinc, it is not possible to determine with certainty, based on the deposited thicknesses, how this layer of metallic zinc or indium is modified following heat treatment.

[0071] The term "metallic layer" means a layer comprising no more than 30%, 20% or 10% oxygen and / or nitrogen as an atomic percentage in the layer.

[0072] The coatings are deposited in metallic form. Following deposition and before heat treatment, they should not contain more than 10% oxygen and / or nitrogen. However, depending on the nature of the coating deposited directly above, these zinc-based metallic coatings are susceptible to partial oxidation, which can lead to higher proportions of oxygen or nitrogen. These proportions are, however, less than 30% or 20%. In any case, at least a portion of the thickness of these zinc- or indium-based metallic coatings is not oxidized or nitrided.

[0073] Zinc-based metallic layers, (before heat treatment), comprise at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% by mass of zinc relative to the mass of the zinc-based metallic layer.

[0074] The indium-based metallic layers, (before heat treatment), comprise at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% by mass of indium relative to the mass of the indium-based metallic layer.

[0075] The zinc-based metallic layers can be selected from: - the metallic layers of zinc, - doped zinc metallic layers, - metallic layers based on zinc alloy.

[0076] According to the invention, the term "zinc metallic layer" refers to metallic layers of pure zinc, which may nevertheless contain some impurities. In this case, the total mass of zinc represents at least 99% by mass of the mass of the zinc-based metallic layer.

[0077] According to the invention, the doped zinc layers comprise at least 90.0%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% by mass of zinc of the mass of the zinc-based metallic layer.

[0078] The doped zinc layers can be selected from layers based on zinc and at least one element selected from titanium, nickel, aluminum, tin, niobium, chromium, magnesium, copper, silicon, silver or gold.

[0079] According to the invention, the zinc alloy-based layers comprise at least 20% at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90% by mass of zinc of the mass of the zinc-based metallic layer.

[0080] Zinc alloy-based layers can be selected from layers based on zinc and at least one element selected from titanium, nickel, chromium, and tin. Examples include binary alloys of zinc and titanium such as Zn2Ti or ternary alloys based on zinc, nickel, and chromium such as ZnNiCr.

[0081] The thickness of the zinc or indium-based metallic layer is from 0.2 to 10 nm.

[0082] The thickness of the zinc- or indium-based metallic layer can be: - greater than or equal to 0.2 nm, greater than or equal to 0.5 nm, greater than or equal to 1.0 nm, greater than or equal to 1.2 nm or greater than or equal to 1.5 nm, greater than or equal to 2 nm and / or - less than or equal to 10 nm, less than or equal to 8 nm, less than or equal to 7 nm, less than or equal to 6 nm, less than or equal to 5 nm or less than or equal to 4 nm.

[0083] Preferably, the zinc- or indium-based metallic layer(s) are located above the silver-based functional metallic layer.

[0084] The coating comprises a blocking layer located above and immediately in contact with the silver-based functional metal layer and / or a blocking layer located below and immediately in contact with the silver-based functional metal layer.

[0085] Preferably, the zinc- or indium-based metal layer(s) are located above a silver layer and above a blocking layer. In this configuration, the zinc- or indium-based metal layer is located above the functional silver-based metal layer and is separated from this layer by at least one blocking overlayer.

[0086] The blocking layers are chosen from metallic layers based on a metal or a metallic alloy, metallic nitride layers, metallic oxide layers and metallic oxynitride layers of one or more elements chosen from titanium, nickel, chromium, tantalum and niobium such as Ti, TiN, TiOx, Nb, NbN, Ni, NiN, Cr, CrN, NiCr, NiCrN.

[0087] When these blocking layers are deposited in metallic, nitrided or oxynitrided form, these layers can undergo partial or total oxidation depending on their thickness and the nature of the layers surrounding them, for example, at the time of deposition of the next layer or by oxidation in contact with the underlying layer.

[0088] The blocking layers can be chosen from: - metallic layers, in particular those made of a nickel-chromium alloy (NiCr), or titanium, - metallic nitride layers, in particular titanium nitride or nickel and / or chromium nitride.

[0089] Advantageously, the blocking layers are nickel-based metallic layers. The nickel-based metallic blocking layers may comprise, (before heat treatment), at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% by mass of nickel relative to the mass of the nickel-based metallic layer.

[0090] Nickel-based metallic layers can be selected from: - the metallic nickel layers, - doped nickel metallic layers, - metallic layers based on nickel alloy.

[0091] Nickel alloy-based metallic layers can be nickel and chromium alloy-based.

[0092] Each blocking layer has a thickness between 0.1 and 5.0 nm. The thickness of these blocking layers can be: - of at least 0.1 nm, of at least 0.2 nm, of at least 0.5 nm and / or - at most 5.0 nm, at most 4.0 nm, at most 3.0 nm, at most 2.0 nm.

[0093] In advantageous embodiments, the coating also comprises a crystalline dielectric layer located below and near the silver layer. These crystalline dielectric layers are generally zinc oxide-based layers.

[0094] The zinc- or indium-based metallic layer may be located: - above a functional silver-based metallic layer, the metallic zinc layer is in contact with the functional silver-based metallic layer (Ag / Zn sequence), - above a functional silver-based metallic layer, the metallic zinc layer is separated from the functional silver-based metallic layer by at least one blocking overlayer (Ag / / Blocking layer / / Zn sequence), - above a functional silver-based metallic layer and below and in contact with a conductive oxide layer, the metallic zinc layer is separated from the functional silver-based metallic layer by at least one blocking overlayer (sequence Ag / / Blocking layer / / Zn / / Conductive oxide layer), - below a functional silver-based metallic layer, the metallic zinc layer is in contact with the functional silver-based metallic layer (Zn / Ag sequence) - beneath a functional silver-based metallic layer, the metallic zinc layer is separated from the functional silver-based metallic layer by minus a blocking sublayer (Zn / / Blocking Layer / / Ag sequence), - below a silver-based functional metallic layer and above and in contact with a crystalline dielectric layer, the metallic zinc layer is in contact with the silver-based functional metallic layer (Crystalized Layer / Zn / Ag sequence), - below a silver-based functional metallic layer and above and in contact with a crystallized dielectric layer, the metallic zinc layer is separated from the silver-based functional metallic layer by at least one blocking sublayer (sequence Crystallized layer / Zn / / Blocking layer / / Ag), - below a functional silver-based metallic layer and below, and in contact with a crystallized dielectric layer, the crystallized dielectric layer is in contact with or separated from the functional silver-based metallic layer by at least one blocking sublayer (Zn / Crystallized layer / / possibly Blocking layer / / Ag sequence).

[0095] The physical thickness of all the layers separating the functional silver-based metal layer from the zinc or indium-based metal layer can be between 0 and 15.0 nm, or even between 0 and 10 nm, or even between 0 and 5 nm, between 0.2 and 5 nm, between 0.5 and 3 nm, between 0.8 and 1.5 nm.

[0096] The thickness of all the layers separating the functional silver-based metallic layer from the zinc- or indium-based metallic layer can be: - greater than or equal to 0.2 nm, greater than or equal to 0.4 nm, greater than or equal to 0.5 nm, greater than or equal to 1 nm, greater than or equal to 2 nm, greater than or equal to 3 nm, greater than or equal to 4 nm, greater than or equal to 5 nm, greater than or equal to 6 nm, greater than or equal to 7 nm, greater than or equal to 8 nm or greater than or equal to 9 nm and / or - less than or equal to 20 nm, less than or equal to 15 nm, less than or equal to 13 nm, less than or equal to 12 nm, less than or equal to 11 nm, less than or equal to 10 nm, less than or equal to 9 nm or less than or equal to 8 nm, less than or equal to 7 nm, less than or equal to 6 nm, less than or equal to 5 nm, less than or equal to 4 nm, less than or equal to 3 nm, less than or equal to 2 nm, less than or equal to 1.5 nm.

[0097] The configuration in which the zinc- or indium-based metal layer is located above and separated from the silver-based functional metal layer by a blocking overlayer appears to give the best results.

[0098] It is also possible to use a blocking underlayer in these configurations. The use of the blocking underlayer improves mechanical strength. A blocking underlayer is then combined below a silver layer with a zinc- or indium-based metallic layer located above and directly in contact with said silver layer or separated from the silver layer. by a blocking overlayer.

[0099] According to the invention, "layer located near" means a layer located, in increasing order of preference, less than 15 nm, less than 10 nm, less than 5 nm, less than 4 nm, less than 3 nm, less than 2 nm from another layer.

[0100] The following embodiments are particularly advantageous because they give the best results: - the metallic layer based on zinc or indium is located near the silver layer and / or - the zinc or indium-based metallic layer is separated from the silver layer by at least one blocking layer, and / or - the metallic layer based on zinc or indium is located above the silver layer, and / or - the coating includes a blocking layer located immediately above and in contact with the functional silver-based metallic layer.

[0101] For zinc- or indium-based metallic layers to be effective, they must allow the diffusion of metallic zinc or indium elements into the silver layer. It is likely that if these zinc layers are separated from the silver layer: - by one or more excessively thick dielectric layers, for example excessively thick layers of zinc and tin oxide and / or - by one or more dielectric barrier layers such as silicon and / or aluminum and / or zirconium nitride layers, The diffusion of these metallic zinc or indium elements will be greatly reduced or even prevented. The zinc or indium-based metallic layer then becomes ineffective in terms of improving electrochemical properties.

[0102] The electroconductive coating may comprise one or more metallic layers based on zinc or indium.

[0103] The electroconductive coating comprises at least one functional layer and at least two dielectric coatings comprising at least one dielectric layer, such that each functional layer is disposed between two dielectric coatings.

[0104] For the purposes of this invention, "dielectric coating" means that there may be one or more layers of different materials within the coating. A "dielectric coating" according to the invention comprises primarily dielectric layers. However, according to the invention, these coatings may also comprise layers of other types, in particular absorbent layers, for example, metallic layers.

[0105] A "same" dielectric coating is considered to be located: - between the substrate and the first functional layer, - between each functional silver-based metallic layer, - above the last functional layer (the one furthest from the substrate).

[0106] For the purposes of this invention, "dielectric layer" means a material that is "non-metallic" in nature, i.e., not a metal. In the context of this invention, the term refers to a material having an n / k ratio over the entire visible wavelength range (from 380 nm to 780 nm) equal to or greater than 5. n denotes the actual 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 being calculated at a given wavelength as identical for n and k.

[0107] The thickness of a dielectric coating corresponds to the sum of the thicknesses of the layers constituting it.

[0108] The coatings have a thickness greater than 15 nm, preferably between 15 and 200 nm.

[0109] The dielectric layers of the coatings have the following characteristics, alone or in combination: - They are deposited by magnetic field-assisted sputtering, - They are chosen from oxides or nitrides of one or more elements chosen from titanium, silicon, aluminum, zirconium, tin, indium and zinc, - they have a thickness greater than 2 nm, preferably between 2 and 100 nm.

[0110] The dielectric coating located above the silver-based metallic functional layer must be sufficiently conductive so that the electroconductive coating retains its electrode function.

[0111] The dielectric coating located above the silver-based metallic functional layer comprises at least one conductive oxide layer. The conductive oxide layers are selected from indium oxide, mixed tin and indium oxide, tin-doped indium oxide (ITO “Indium Tin Oxide”), tin oxide, doped tin oxide, zinc oxide, doped zinc oxide such as zinc oxide doped in particular with aluminium (AZO) and / or gallium, ruthenium oxide, doped ruthenium oxide and fluorine-doped tin oxide (SnO2:F).

[0112] Preferably, mixed tin and indium oxide (ITO) or zinc oxide doped with aluminium and / or gallium is used.

[0113] The sum of the thicknesses of all the conductive oxide layers located in the dielectric coating directly above the silver-based functional layer is greater than 50 nm or greater than 60 nm.

[0114] The sum of the thicknesses of all the conductive oxide layers located in the dielectric coating directly above the functional base layer silver is less than 150 nm, less than 100 nm or less than 80 nm.

[0115] Preferably, the dielectric coating located directly above the silver-based functional layer comprises at least one conductive oxide layer with a thickness greater than 50 nm or 60 nm.

[0116] Preferably, the dielectric coating located directly above the silver-based functional layer comprises at least one aluminum-doped zinc oxide-based conductive oxide layer with a thickness greater than 50 nm or 60 nm.

[0117] According to one embodiment, the dielectric coating may comprise at least two layers, an aluminum-doped zinc oxide layer and a mixed indium tin oxide (ITO) layer.

[0118] According to the invention, indium tin oxide (or tin-doped indium oxide, or ITO) is understood to be a mixed oxide or mixture obtained from indium(III) (In₂O₃) and tin(IV) (SnO₂) oxides, preferably in mass proportions of between 70 and 95% for the former and 5 to 20% for the latter. A typical mass proportion is approximately 90% In₂O₃ to approximately 10% SnO₂.

[0119] According to the invention, the conductive zinc oxide-based layers may comprise at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% by mass of zinc relative to the total mass of all the elements constituting the zinc oxide-based layer, excluding oxygen and nitrogen. To be sufficiently conductive, the zinc oxide-based layers are doped with at least one other element, referred to as the "dopant element." The zinc oxide-based layers may therefore comprise one or more dopant elements selected from aluminum, titanium, niobium, zirconium, magnesium, copper, silver, gold, silicon, molybdenum, nickel, chromium, platinum, indium, tin, and hafnium, preferably aluminum.

[0120] Conductive layers based on doped zinc oxide may include: - at least 1%, at least 2% or at least 5%, and / or - at most 15% or at most 10%, in mass of dopant elements relative to the total mass of all elements constituting the zinc oxide-based layer, excluding oxygen and nitrogen.

[0121] The dielectric coating located beneath the silver-based metallic functional layer does not necessarily have to be conductive. Advantageously, it may comprise a crystalline layer, also called a stabilizing or wetting layer. A stabilizing layer is defined as a layer made of a material capable of stabilizing the interface with the functional layer. These layers are generally zinc oxide-based.

[0122] Zinc oxide-based coatings may comprise at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% by mass of zinc relative to the total mass of all elements constituting the zinc oxide-based layer excluding oxygen and nitrogen.

[0123] To be properly crystallized by sputtering deposition, zinc oxide-based layers advantageously comprise at least 80%, or even at least 90% by mass of zinc relative to the total mass of all the elements constituting the zinc oxide-based layer, excluding oxygen and nitrogen.

[0124] Zinc oxide-based layers may comprise one or more elements selected from aluminium, titanium, niobium, zirconium, magnesium, copper, silver, gold, silicon, molybdenum, nickel, chromium, platinum, indium, tin and hafnium, preferably aluminium.

[0125] Zinc oxide-based layers may optionally be doped with at least one other element, such as aluminium.

[0126] The zinc oxide-based layer comprises, in order of increasing preference, at least 80%, at least 90%, at least 95%, at least 98%, at least 100%, by mass of oxygen relative to the total mass of oxygen and nitrogen.

[0127] Preferably, the dielectric coating located directly below the functional silver-based metallic layer comprises at least one crystalline dielectric layer, in particular based on zinc oxide, optionally doped with at least one other element, such as aluminum.

[0128] These zinc oxide layers have a thickness: - of at least 1.0 nm, at least 2.0 nm, at least 3.0 nm, at least 4.0 nm or at least 5.0 nm, and / or - of at most 25 nm, of at most 15 nm, of at most 10 nm or of at most 8.0 nm.

[0129] Preferably, the dielectric coating located directly below the silver-based functional metal layer comprises at least one barrier dielectric layer. A barrier dielectric layer (hereinafter referred to as a barrier layer) is defined as a layer made of a material capable of blocking the diffusion of oxygen and water at high temperatures from the ambient atmosphere or the transparent substrate to the functional layer. Such dielectric layers are selected from the following: - based on silicon and / or aluminum and / or zirconium compounds selected from oxides such as SiO2, nitrides such as silicon nitride Si3N4 and aluminum nitrides AIN, and oxynitrides SiOxNy, possibly doped with at least one other element, - based on zinc and tin oxide, - based on titanium oxide.

[0130] These dielectric barrier layers have, in increasing order of preference, a thickness:

[0131] - less than or equal to 40 nm, less than or equal to 30 nm, less than or equal to 25 nm, and / or

[0132] - greater than or equal to 5 nm, greater than or equal to 10 nm or greater than or equal to 15 nm.

[0133] Preferably, the first dielectric coating comprises: - a layer based on an aluminum nitride or oxynitride and / or silicon and / or zirconium, and / or - a layer based on a mixed zinc and tin oxide, and / or - a layer based on an aluminium and / or silicon and / or zirconium nitride or oxynitride and a dielectric layer based on a mixed zinc and tin oxide located above, preferably in contact with, the layer based on an aluminium and / or silicon and / or zirconium nitride or oxynitride.

[0134] The zinc tin oxide-based layer may have a thickness of between 2 and 30 nm, preferably between 5 and 20 nm. The layer based on an aluminum and / or silicon and / or zirconium nitride or oxynitride may have a thickness of between 2 and 30 nm, preferably between 5 and 20 nm. The zinc tin oxide-based layer is located below, preferably in contact with, a zinc oxide-based layer.

[0135] The substrate coated with the electroconductive coating, or the coating alone, is intended to undergo heat treatment. However, the present invention also relates to the unheat-treated material.

[0136] The electroconductive coating may not have undergone heat treatment at a temperature above 500 °C, preferably 300 °C.

[0137] The coating may have undergone heat treatment at a temperature above 300 °C, preferably 500 °C.

[0138] The heat treatments are selected from annealing, for example by rapid thermal processing such as laser or flash lamp annealing, quenching, and / or bending. Rapid thermal annealing is described, for example, in application WO2008 / 096089. The heat treatment temperature (at the coating level) is above 300 °C, preferably above 400 °C, and better above 500 °C.

[0139] The substrate coated with the coating can be curved or tempered glass.

[0140] The transparent substrates according to the invention are preferably made of a rigid mineral material, such as glass, or organic polymer-based (or polymer).

[0141] The transparent organic substrates according to the invention can also be made of polymer, rigid or flexible. Examples of suitable polymers according to the invention include, in particular:

[0142] - polyethylene,

[0143] - polyesters such as polyethylene terephthalate (PET), polybutylene te- rephthalate (PBT), polyethylene naphthalate (PEN);

[0144] - polyacrylates such as polymethyl methacrylate (PMMA);

[0145] - polycarbonates;

[0146] - polyurethanes;

[0147] - polyamides;

[0148] - polyimides;

[0149] - fluorinated polymers such as fluoroesters like ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene ethylene (ECTFE), fluorinated ethylene-propylene copolymers (FEP);

[0150] - photocurable and / or photopolymerizable resins, such as resins thiolene, polyurethane, urethane-acrylate, polyester-acrylate and

[0151] - polythiomethanes.

[0152] The substrate is preferably a sheet of glass or glass-ceramic.

[0153] The substrate is preferably transparent, colorless (in which case it is clear glass or extra clear) or colored, for example in blue, gray or bronze. The glass is preferably of the soda-lime silicate type, but it can also be of the borosilicate or aluminoborosilicate type.

[0154] According to a preferred embodiment, the substrate is made of glass, in particular soda-lime silico-glass or of polymeric organic matter.

[0155] The substrate advantageously has at least a dimension greater than or equal to 1 m, or even 2 m and even 3 m.

[0156] The substrate thickness generally varies between 0.05 mm and 19 mm. When the substrate is mineral, its thickness is preferably between 0.7 and 9 mm, particularly between 2 and 8 mm, or even between 4 and 6 mm. The substrate may be flat or convex, or even flexible. When the substrate is organic, its thickness is preferably between 1 and 2 mm. Examples I. Electroconductive Coatings

[0157] Electroconductive coatings were deposited by sputtering onto a transparent glass substrate. The glass substrates are 2.1 mm aluminosilicate glass substrates.

[0158] The functional layers (F) are silver-based metallic layers.

[0159] Dielectric coatings include: - silicon nitride-based layers, - layers based on zinc and tin oxide, - layers of aluminum-doped zinc, - layers of indium and tin.

[0160] The blocking layers are chosen from titanium, titanium nitride, nickel and chromium, and zinc layers. The deposition conditions of the layers, which were deposited by sputtering (so-called "magnetron cathode sputtering"), are summarized in Table 1. [Tables 1] Target Layer Used Pressure Pa Gas ITO In2O3 90%, SnO2 10% wt. 0.2 Ar / (Ar + O2) at 99% Zn Zn 0.2 Ar at 100% NiCr Ni:Cr at 80%:20% by wt. 0.2 Ar at 100% TiN Ti 0.1 to 1 Ar 85% - N2 15% Ti Ti 0.1 to 1 Ar at 100% Ag Ag 0.1 to 1 Ar at 100% SnZnO Zn:Sn at 64:36% at. 0.1 to 1 Ar / (Ar + O2) at 50% Si3N4 Si:Al at 92:8% by wt. 0.32 Ar / (Ar + N2) at 55%

[0161] Table 2 lists the materials and thicknesses in nm (unless otherwise indicated) of each layer or coating which constitutes the coatings according to their position with respect to the substrate carrying the stack (last line at the bottom of the table).

[0162] [Tables2] Rev. electroconductor Rev. 1 Rev. 6 Rev. 7 Inv. 4 RD Sup. AZO 60 60 60 60 Zn - - - 2 CB Ti 0.5 - - - TiN - - - - NiCr - 1 - 1 Zn - - 2 - CF Ag 10 10 10 10 RD lower AZO 5 5 5 5 SnZnO 5 5 5 5 Si3N4 20 20 20 20 Glass substrate 2 mm 2 mm 2 mm 2 mm

[0163] The first dielectric coatings include a SiN / SnZnO / ZnO sequence to prevent the diffusion of chemical species from the substrate and to decrease surface roughness and optimize the quality of the silver. II. Determination of electrochemical properties

[0164] In order to determine the electrochemical properties of the conductive coatings with respect to mobile species of the electrolyte such as Li / Li+, voltammetric cycles were carried out. For this purpose, the current response resulting from a continuous variation of the potential of the electroconductive coating (used as a working electrode) on which the electrochemical reaction under study takes place is measured.

[0165] Figures 1 and 2 show voltammetric cycles performed using a three-electrode setup with a metallic lithium counter electrode, a metallic lithium reference electrode, and a working electrode comprising the various electroconductive coatings. The electrolyte consists of a LiC104 / PC solution.

[0166] The voltamograms are carried out in the potential window of 2 to 4 V relative to Li / Li+ at a sweep rate of 2 mV / s.

[0167] [Fig.3] is an enlargement of [Fig.2] around 3.7 V.

[0168] The electroconductive coatings tested in [Fig. 1] were not subjected to heat treatment. The electroconductive coatings tested in [Fig. 2] were subjected to heat treatment at 600°C for 8 minutes. 1. Absence of heat treatment

[0169] In [Fig. 1], for coatings Rev. 1 and Rev. 7, comprising respectively a titanium-based or metallic zinc-based blocking layer, no oxidation reaction is observed between 2 V and 3.4 V. A slight increase in current density is observed around 3.4 V vs. Li / Li+, followed by a sharp increase around 3.7 V vs. Li / Li+. This sharp increase is attributable to the oxidation of metallic Ag to Ag+ ions, which dissolve in the electrolyte. This demonstrates that such electroconductive coatings cannot be used in electrochromic devices. The presence alone of a metallic zinc-based layer or a metallic titanium layer near the silver layer does not show any positive effect. The presence of redox peaks indicates electrode degradation.

[0170] Rev. 6, comprising a NiCr-based blocking layer, does not exhibit redox peaks. In the absence of heat treatment, a NiCr-based blocking layer alone improves the stability range of the silver-based electroconductive coating.

[0171] The Inv.4 coating according to the invention, comprising a NiCr-based blocking layer and a metallic zinc layer, does not exhibit redox peaks. Therefore, an improvement in electrochemical stability is observed. An increase in current is observed at high potentials. This could be attributed to the increase in the coating's conductivity due to the contribution of the metallic zinc layer. 2. After heat treatment

[0172] After heat treatment, redox peaks are observed for Rev.1, Rev.7 and Rev.6. This means that the electroconductive coating is degraded.

[0173] For rev.7 comprising a blocking layer based solely on metallic zinc, this phenomenon is particularly significant. An increase in current above 3.4 V is observed, as well as redox peaks at 3.6 and 3.7 V. After heat treatment, the presence of a metallic zinc layer alone does not improve the electrochemical stability of silver.

[0174] For Rev.6, which includes a NiCr-based blocking layer, the positive impact of this layer is weaker in the case of heat treatment. Indeed, although the increase around 3.4V is small, peaks of reduction at 3.6V relative to Li+ / Li are observed, corresponding to silver degradation.

[0175] The best results are obtained for the electroconductive coating of the invention Inv.4. Neither oxidation-reduction peaks nor voltage rise are observed for high potentials.

[0176] The combined effect of the presence of a blocking layer and a metallic zinc layer shows a strong improvement in the electrochemical stability of silver. A very slight increase in current is observed above 3.4 V, and no peak. redox reaction.

[0177] The effect obtained by the particular combination of the invention is superior to the effects obtained individually. A blocking layer of metallic zinc alone does not improve the electrochemical stability of silver. A blocking layer of NiCr does not prevent the oxidation-reduction of the silver layer after heat treatment (above 500°C). Their combination prevents degradation of the silver layer.

[0178] The association of a blocking layer with a metallic zinc layer capable of diffusing and forming an alloy with silver improves the electrochemical stability of the silver-based coating above 3.7V compared to Li / Li+ after heat treatment.

[0179] The invention allows the use of the silver-based coating in a high-contrast electro-chromic device operating in the 2-4V vs Li / Li+ range.

Claims

Demands

1. A material comprising a substrate coated with a first conductive coating comprising, starting from the substrate: - a first dielectric coating, - a silver-based metallic functional layer, - a blocking layer located immediately in contact with the silver-based metallic functional layer, selected from metallic layers based on a metal or a metallic alloy, metallic nitride layers, metallic oxide layers and metallic oxynitride layers, of one or more elements selected from titanium, nickel, chromium, tantalum and niobium, aluminum oxide layers and silicon oxide layers, - at least one zinc- or indium-based metallic layer, located above or below this silver-based metallic functional layer, directly in contact with or separated by one or more layers having a total thickness less than or equal to 20 nm,- a second dielectric coating comprising at least one conductive oxide layer, the sum of the thicknesses of the conductive oxide layers in the second dielectric coating being greater than 30 nm,

2. 11111. Material according to claim 1, characterized in that the blocking layer has a thickness between 0.1 and 5.0 nm.

3. Material according to any one of the preceding claims, characterized in that the blocking layer is selected from a titanium nitride layer, nickel and / or chromium-based metal layers, nickel and / or chromium oxide layers, aluminum oxide layers, silicon oxide layers.

4. Material according to any one of the preceding claims, characterized in that the zinc- or indium-based metallic layer is separated from the silver-based functional metallic layer by at least one blocking layer.

5. Material according to any one of the preceding claims, characterized in that the thickness of all layers separating the silver-based functional metal layer from the zinc- or indium-based metal layer is less than or equal to 10 nm.

6. Material according to any one of the preceding claims, characterized in that the thickness of the zinc-based metallic layer or the range of indium is from 0.2 to 10 nm.

7. Material according to any one of the preceding claims, characterized in that the second dielectric coating comprises a conductive oxide layer selected from mixed tin and indium oxide or zinc oxide doped with aluminum and / or gallium.

8. Material according to any one of the preceding claims, characterized in that the second dielectric coating comprises a conductive oxide layer based on aluminum-doped zinc oxide with a thickness greater than 50 nm.

9. Material according to any one of the preceding claims, characterized in that the first dielectric coating comprises at least one crystalline dielectric layer, in particular based on zinc oxide, optionally doped with at least one other element, such as aluminium.

10. Material according to any one of the preceding claims, characterized in that the first dielectric coating comprises: - a layer based on silicon nitride or oxynitride, aluminium and / or zirconium, and / or - a layer based on zinc oxide and tin.

11. Material according to any one of the preceding claims characterized in that the conductive coating has undergone heat treatment at a temperature above 300 °C, preferably 500 °C.

12. Material according to the preceding claim characterized in that the silver-based functional layer comprises zinc.

13. An electrochromic system comprising: - a material comprising a substrate coated with a first conductive coating comprising, starting from the substrate: - a first dielectric coating, - a metallic functional layer comprising a silver-based layer, - a blocking layer situated immediately in contact with the silver-based metallic functional layer, selected from metallic layers based on a metal or a metallic alloy, metallic nitride layers, metal oxide layers and metal oxynitride layers of one or more elements selected from titanium, nickel, chromium, tantalum and niobium, aluminum oxide layers and silicon oxide layers, - at least one zinc-based metallic layer, situated above or below beneath this functional silver-based metallic layer, either directly in contact or separated by one or more layers whose total thickness is less than or equal to 20 nm, - a second dielectric coating comprising at least one conductive oxide layer, the sum of the thicknesses of the conductive oxide layers in the second dielectric coating being greater than 30 nm, - a first active layer comprising an electrochromic material, - an electrolyte layer, - a second active layer and - a second transparent electroconductive coating, - possibly a substrate.

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