Electrochromic glazing

Abstract

The invention relates to a material comprising a substrate coated with a first electrically conductive coating, said first electrically conductive coating comprising, starting from the substrate:-a first dielectric coating,-a functional silver-based metal layer,-a barrier layer located in direct contact with the functional silver-based metal layer,-a second dielectric coating,-a functional silver-based metal layer,-a second barrier layer located in direct contact with the functional silver-based metal layer, -at least one zinc-based metal layer located above or below the silver-based metal functional layer, in direct contact with the silver-based metal functional layer or separated by one or more layers, the one or more layers having a total thickness of 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 layer is greater than 30 nm.

Description

[0001] The present invention relates to the field of electrochromic (EC) glazing. In particular, the present invention relates to a conductive coating for electrochromic devices, 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 infrared range under the action of an electric voltage, thus making it possible to obtain easily adjustable electrically controllable coatings.

[0003] Known electrochromic devices are characterized by an electrochromic system comprising a series of at least five layered elements essential for the operation of the device, that is to say for the reversible color change upon application of an appropriate electrical supply. These five layered elements are as follows:

[0004] - a first transparent conductive coating,

[0005] - a first active layer acting as an electrode,

[0006] - electrolyte layer,

[0007] - a second active layer acting as a counter electrode, and

[0008] - A second transparent conductive coating.

[0009] At least one active layer is based on an electrochromic material.

[0010] The five layered elements are typically in contact with one or two transparent substrates.

[0011] Electrochromic systems fall into three categories:

[0012] - "All-solid" inorganic technology,

[0013] - "hybrid" technology,

[0014] - "All-Polymer" technology.

[0015] In "all-solid" electrochromic systems, all layers are made of solid inorganic 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.

[0016] Hybrid electrochromic systems comprise an inorganic active layer framing an electrolyte layer based on an ion-conducting polymer. These systems conventionally comprise two substrates surrounding the electrochromic system. Examples of hybrid EC systems are described in patent applications EP-382 623, EP-518 754 and EP-532 408.

[0017] In “all-polymer” electrochromic systems, the active layer and the electrolyte layer are polymer-based.

[0018] The coloration / fading phenomenon in the visible range, or more generally the change of optical properties, is caused by the transfer of charges (ions / electrons) between the two active layers.

[0019] The active layer based on electrochromic material is capable of reversibly inserting ions. When ions migrate into this layer, its optical properties change and it reversibly transforms from a faded state to a colored state. The other active layer can also be based on an electrochromic material.

[0020] Inorganic electrochromic materials are mainly transition metal oxides, which are divided into two categories: cathode-colored oxides, such as tungsten oxide WO3, which is colored in the reduced state, and anodic-colored oxides, such as iridium oxide (IrO x ) and nickel oxide (NiO x ), which colors in the oxidized state. Cathode and anodic electrochromic material pairs are typically selected, such as a cathode material that colors in the intercalated state combined with an anode material that fades in the intercalated state.

[0021] The electrolyte layer must have good ionic conductivity and be electrically insulating. The electrolyte in the electrochromic system ensures that mobile ions pass through within their electrochemical stability range. In theory, all monovalent ions such as H + , Li + 、Na + , K + 、Ag + , divalent ions such as Zn 2+ and trivalent ions such as Al 3+ Lithium salts, alkali metal salts or hydrogen salts are particularly suitable.

[0022] For example, when a tungsten oxide (WO3) active layer is in contact with a lithium ion conductive electrolyte layer, Li + Ions are transferred between the electrodes. The following electrochemical reactions are observed at the cathode: 6+ O 2- 3(transparent)+x Li + +xe - →Li + x W 6+1-x W 5 + x O 2- 3(blue).

[0023] Voltammetry can be used to determine the voltage range that provides the best contrast between the colored and faded states. The voltammetric cycle or curve or voltammogram (j=f(V)) involves tracking the change in current density j over a scanning potential interval. The study of the change in current density is of great significance to the electrochemical behavior of the material. The coloration potential (V 着色 ), fading potential (V 褪色 ) corresponds to the oxidation reaction in the anodic part (j>0) or the reduction reaction in the cathodic part (j<0) of the curve, and the stability range can be directly deduced from these curves.

[0024] If an electrochromic device comprising a cathodically coloring active layer based on tungsten oxide and an electrolyte layer comprising lithium ions is considered, a colored state is observed at 2.3 V and at 3.2 V (vs. Li / Li + ) was observed to be discolored.

[0025] If an electrochromic device comprising an anodically coloring active layer based on nickel oxide and an electrolyte layer comprising lithium ions is considered, the oxidation potential associated with lithium ion deintercalation is approximately 4 V, while the fading voltage can be adjusted between 1 V and 2.5 V by doping the nickel oxide.

[0026] If we consider known all-polymer EC systems comprising an electrolyte layer comprising lithium ions, the voltage range between the less transparent state and the more transparent state is relative to Li / Li + 2V to 4V.

[0027] Therefore, for these EC systems, the reactions that enable coloration and fading 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 coloration / fading phenomena.

[0028] The "voltage stability range" of a material refers to the range of potentials to which the material can be exposed without undergoing oxidation or reduction reactions.

[0029] When a material is subjected to an electrochemical potential outside its stability range and in the presence of the corresponding ions, redox reactions occur.

[0030] In the case of electrochromic systems, the conductive coatings are exposed to the electrochemical potential of the active materials with which they are in contact. This means that the conductive coatings of electrochromic devices must be at a constant relative to the Li / Li +The conductive coating should therefore have a potential window of preferably 1 V to 4 V relative to Li / Li. + The materials that make up these conductive coatings must not undergo any redox reactions within this voltage range.

[0031] Known conductive coatings include conductive functional layers based on transparent conductive oxides, such as indium-tin layers or fluorine-doped tin layers, or metallic functional layers, in particular based on silver.

[0032] Conductive coatings based on conductive oxide layers, although providing excellent electrochemical stability, do not have sufficient conductive properties at high transmittances (>80%). This results in uneven switching and / or a decrease in switching speed as the surface area of ​​the EC system increases. Finally, in some applications (such as automotive applications), additional processing steps are sometimes required, such as quenching or bending. These additional steps may alter the conductive oxide coating. In fact, these coatings need to be thick to achieve the desired resistivity values. However, these thick coatings are sensitive to cracking during thermal treatments.

[0033] Conductive coatings containing silver-based metallic functional layers provide excellent 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 have a low electrochemical stability relative to Li / Li + The couple undergoes oxidation-reduction reactions in the range of 1V-4V. At low potentials, these reactions lead to the reduction of Ag material, the formation of metal alloys (such as LiAg), or the generation of reducing gases (molecular hydrogen). At high potentials, these reactions lead to the reduction of Ag material. + Oxidation of the material, formation of oxides (AgO) and / or generation of oxidizing gases (molecular oxygen). In the context of high potential reactions, one may also speak of "corrosion" of the material.

[0034] Known conductive coatings of this type include:

[0035] - optionally a first dielectric layer or a first dielectric coating,

[0036] - a silver-based metallic layer,

[0037] - optional barrier layer,

[0038] - A second dielectric layer or dielectric coating.

[0039] Cyclic voltammetry was performed to determine the voltage stability range of these conductive coatings using a three-electrode setup with a lithium metal counter electrode, a lithium metal reference electrode and a working electrode containing the conductive coating to be tested. The electrolyte was a LiClO4 / PC solution. The working electrode comprised a 2 mm glass substrate coated with a known silver-based conductive coating comprising the sequence (SiN / SnZnO / Al-doped ZnO / Ag) starting from the substrate. The voltage stability range of these conductive coatings was determined at a scan rate of 2 mV / s relative to Li / Li + The voltammograms were generated in the potential window of 2-4V.

[0040] No oxidation reaction was observed between 2 V and 3.4 V. + A slight increase in current density was observed at about 3.4 V, followed by a + The sharp increase is due to the oxidation of metallic Ag to Ag dissolved in the electrolyte. + ions. This indicates that such conductive coatings cannot be used in electrochromic devices unless the accessible contrast ratio of the EC device is limited by applying a potential below 3.7 V. In this case, full fading or coloration cannot be obtained.

[0041] In order to benefit from the improved optical and conductive properties of silver-based conductive coatings in electrochromic devices, it is necessary to expand their electrochemical stability range.

[0042] The present invention relates to a conductive coating comprising a silver-based metallic functional layer having improved electrochemical stability. The coating of the invention is particularly suitable for use in electrochromic devices.

[0043] The applicant has found that the use of certain barrier layers in combination with a metal layer based on zinc or indium adjacent to a silver-based functional layer results in improved electrochemical stability, in particular with respect to Li / Li + at about 3.7 V. This improvement in electrochemical stability makes conductive coatings based on the described agents suitable for EC applications.

[0044] The present invention relates to a material comprising a substrate coated with a first conductive coating, said first conductive coating comprising, starting from said substrate:

[0045] - a first dielectric coating,

[0046] - a functional metal layer comprising a silver-based layer,

[0047] a barrier layer located in direct contact with the metallic functional layer based on silver, chosen from: metallic layers based on metals or metal alloys of one or more elements chosen from titanium, nickel, chromium, tantalum and niobium, metal nitride layers, metal oxide layers and metal oxynitride layers, aluminum oxide layers and silicon oxide layers,

[0048] at least one metallic layer based on zinc or indium, located above or below the metallic functional layer based on silver, in direct contact with said metallic functional layer based on silver or separated by one or more layers having a total thickness less than or equal to 20 nm,

[0049] - Preferably, a second dielectric coating comprising at least one conductive oxide layer, the sum of the thicknesses of the conductive oxide layers in said second dielectric coating being greater than 30 nm, preferably greater than 40 nm.

[0050] The present invention increases the stability range of silver-based conductive coatings to the same range as Li / Li + Compared to higher than 3.7V.

[0051] The invention also relates to a conductive coating comprising a metallic functional layer, the metallic functional layer comprising a layer based on silver, the conductive coating being preferably transparent and having a relative Li / Li + The conductive coating is electrochemically stable in the potential window of 2 to 4 V.

[0052] - a metallic functional layer comprising a silver-based layer,

[0053] - a barrier layer situated in direct contact with the metallic functional layer based on silver,

[0054] at least one metallic layer based on zinc located above or below the metallic functional layer based on silver, in direct contact with said metallic functional layer based on silver or separated by one or more layers having a total thickness less than or equal to 20 nm.

[0055] The most advantageous properties of the invention are obtained after high temperature heat treatment. The conductive coating or material of the invention, ie the substrate coated with said conductive coating, preferably undergoes high temperature heat treatment, ie at a temperature above 250°C, preferably above 300°C, 400°C or 500°C.

[0056] The purpose of the barrier layer is to improve the electrochemical properties of the silver layer. The barrier layer is preferably based on one or more elements selected from nickel, iron, zirconium, titanium or tungsten, deposited in metallic or nitrided form. The purpose of these barrier layers is to protect the silver layer and prevent ions from the active layer (such as Li + ions) diffusion.

[0057] Without wishing to be bound by any theory, it is possible that a portion of the zinc or indium metal layer will alloy with the silver, especially during high temperature heat treatments. The barrier layer accommodates this doping.

[0058] Each of these layers contributes to improving the electrochemical stability of the silver-based metal layer. However, the combination of the barrier layer with the zinc layer produces the best results in terms of high contrast of the final EC device and electrochemical stability of the conductive coating.

[0059] The layer of zinc or indium metal should be adjacent to the silver layer. It can be located above, below or on both sides of the silver layer.

[0060] Due to this specific coating structure, transparent conductive coatings can be obtained which have an electrochemical resistance compatible with EC systems and which simultaneously have high conductive properties and high light transmission levels, in particular light transmission levels exceeding 60%, 70% or 80%.

[0061] The invention also relates to a material having the following characteristics:

[0062] - the barrier layer has a thickness of 0.1 to 5.0 nm or 0.5 to 2 nm,

[0063] - the barrier layer is selected from titanium nitride layers, metal layers based on nickel and / or chromium, nickel and / or chromium oxide layers, aluminum oxide layers, silicon oxide layers,

[0064] - the barrier layer is chosen from nickel-based metal layers comprising at least 20% by mass of nickel relative to the mass of the nickel-based metal layer,

[0065] - the metallic layer based on zinc or indium is separated from the metallic functional layer based on silver by at least one barrier layer,

[0066] - the thickness of all layers separating the metallic functional layer based on silver from the metallic layer based on zinc or indium is less than or equal to 10 nm,

[0067] - the metallic layer based on zinc or indium is located above the metallic functional layer based on silver,

[0068] - the thickness of the zinc or indium based metal layer is between 0.2 and 10 nm,

[0069] - the zinc-based metal layer comprises at least 20% by mass of zinc, relative to the mass of the zinc-based metal layer,

[0070] - the second dielectric coating comprises a conductive oxide layer selected from tin-indium mixed oxides or zinc oxide doped with aluminum and / or gallium,

[0071] - the second dielectric coating comprises a conductive oxide layer based on aluminum-doped zinc oxide with a thickness greater than 50 nm,

[0072] - said 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 aluminum,

[0073] - said first dielectric coating comprises a layer based on aluminium and / or zirconium silicon nitride or oxynitride, and / or a layer based on zinc tin oxide,

[0074] - the stack has been heat treated at a temperature above 300° C., preferably 500° C., 550° C. or 600° C.,

[0075] - the silver-based functional layer contains zinc,

[0076] - the substrate is made of glass, in particular soda-lime-silica glass, or of a polymeric organic material,

[0077] - the material further comprises a first active layer comprising an electrochromic material located in contact with the conductive coating,

[0078] - the material further comprises an electrolyte layer, the electrolyte layer being located in contact with the first active layer comprising the electrochromic material, preferably the electrolyte being a lithium ion conducting electrolyte,

[0079] - the material further comprises a second active layer in contact with the electrolyte layer,

[0080] - The material further comprises a second conductive coating located in contact with the electrolyte layer.

[0081] The present invention also relates to an electrochromic system comprising:

[0082] - a material according to the invention comprising a first transparent conductive coating,

[0083] - a first active layer comprising an electrochromic material,

[0084] - electrolyte layer,

[0085] - a second active layer, and

[0086] - a second transparent conductive coating,

[0087] - Optional substrate.

[0088] The electrochromic material of the active layer can be based on inorganic materials, such as tungsten oxide, nickel oxide, iridium oxide, cerium oxide, or on organic materials, such as conductive polymers, for example polyaniline or poly(3,4-ethylenedioxythiophene) (PEDOT) or Prussian blue. These materials can insert cations, in particular protons or lithium ions.

[0089] 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 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.

[0090] 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 and 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).

[0091] If the electrochromic material of the first active layer is tungsten oxide, that is to say a cathodic electrochromic material whose coloration state corresponds to the highest reduction state, an anodic electrochromic material based on nickel oxide or iridium oxide can be used, for example, for the counter electrode. In particular, this can be a layer of mixed vanadium-tungsten oxide or mixed nickel-tungsten oxide.

[0092] The thickness of the active layer is generally 50 nm to 600 nm, in particular 150 nm to 250 nm.

[0093] The thickness of the electrolyte layer may 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.

[0094] The two conductive coatings must be connected to their corresponding power supply connectors. These connectors, such as busbars and wires, are in contact with the conductive coatings to provide appropriate power supply.

[0095] The invention also relates to an electrochromic system comprising two substrates held together by a housing or frame.

[0096] Throughout this specification, the substrate according to the invention is considered to be placed horizontally. The conductive coating is deposited above the substrate. The meaning of the expressions "above" and "below" as well as "below" and "on" should be considered relative to this orientation. Unless otherwise specified, the expressions "above" and "below" do not necessarily mean that two layers and / or coatings are positioned in contact with each other. When it is specified that a layer is deposited "in contact" with another layer or with a coating, this means that one (or more) intervening layers cannot be present between the two layers (or between a layer and a coating).

[0097] All optical properties presented in the description have been obtained according to the principles and methods described in European Standard EN 410 relating to the determination of optical and solar properties of glazing units used in the building industry glazing.

[0098] The preferred properties that appear in the remainder of the description also apply to the material according to the invention and, where appropriate, to the glazing or system according to the invention.

[0099] The 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.

[0100] Unless otherwise mentioned, thicknesses mentioned in this document are physical thicknesses.

[0101] The invention is suitable for single-layer functional coatings based on silver. This solution is also suitable for coatings with multiple functional layers based on silver, in particular two or three functional layers. The coating contains at least one or only one metallic functional layer based on silver.

[0102] The silver-based functional metal layer comprises at least 95.0% by weight, preferably at least 96.5% by weight and even better still at least 98.0% by weight of silver, relative to the weight of the functional layer, before or after the heat treatment.

[0103] Preferably, the silver-based functional metal layer contains less than 1.0 wt % of metal other than silver, relative to the weight of the silver-based functional metal layer, before the heat treatment.

[0104] After the heat treatment, the silver-based functional metal layer may contain a certain proportion of zinc or indium. Zinc or indium doping can be measured, for example, by ElectroProbe MicroAnalyzer (EPMA) or Atom Probe Tomography.

[0105] The thickness of the silver-based functional layer is 5 to 25 nm.

[0106] The zinc-based metal layer is in a dielectric coating in contact with the silver-based metal functional layer. This means that the zinc-based metal layer is not separated from the silver-based metal functional layer by another silver-based metal functional layer.

[0107] The presence of a zinc or indium metal layer adjacent to a silver layer results in the migration of the zinc metal element into the silver layer, particularly during heat treatment. The presence of a barrier layer in contact with the silver layer appears to slow the diffusion of the zinc or indium metal through the silver layer.

[0108] Consider the case where a zinc-based metal layer is located above a silver layer. If metallic zinc elements diffuse at a temperature lower than the heat treatment temperature, in the absence of a barrier coating, they can easily pass through the silver layer without being fully retained. In contrast, when a barrier coating is inserted between the silver layer and the zinc layer, the barrier layer can act as a barrier and slow down the diffusion of metallic zinc elements. This retains metallic zinc elements in the silver layer.

[0109] To a lesser extent, the use of a blocking underlayer also serves to prevent diffusion of the metallic zinc element and confine it to the vicinity of the silver layer. The configuration according to this embodiment may be advantageous.

[0110] Preferably, the barrier layer is located between the functional layer and the metal layer based on zinc or indium.

[0111] In the following paragraphs, metal layers based on zinc or indium are defined as those obtained during deposition, ie before heat treatment. Since heat treatment triggers the migration of metallic zinc elements, it is not possible to determine from the deposited thickness how the zinc or indium metal layer is modified by the heat treatment.

[0112] A “metal layer” is understood to mean a layer which contains not more than 30%, 20% or 10% oxygen and / or nitrogen in atomic percentages in the layer.

[0113] The layers are deposited in metallic form. After deposition and before heat treatment, they should contain no more than 10% of oxygen and / or nitrogen. However, depending on the nature of the layer deposited directly above, these zinc-based metallic layers are susceptible to partial oxidation, which can lead to higher proportions of oxygen or nitrogen. However, these proportions are lower than 30% or 20%. In any case, at least a portion of the thickness of these zinc- or indium-based metallic layers is not oxidized or nitrided.

[0114] The zinc-based metal barrier layer (before heat treatment) comprises at least 20 mass%, at least 30 mass%, at least 40 mass%, at least 50 mass%, at least 60 mass%, at least 70 mass%, at least 80 mass%, at least 90 mass%, at least 95 mass%, at least 96 mass%, at least 97 mass%, at least 98 mass%, at least 99 mass%, or 100 mass% zinc, relative to the mass of the zinc-based metal layer.

[0115] The indium-based metal barrier layer (before heat treatment) contains at least 20 mass%, at least 30 mass%, at least 40 mass%, at least 50 mass%, at least 60 mass%, at least 70 mass%, at least 80 mass%, at least 90 mass%, at least 95 mass%, at least 96 mass%, at least 97 mass%, at least 98 mass%, at least 99 mass%, or 100 mass% indium relative to the mass of the indium-based metal layer.

[0116] The zinc-based metal layer may be selected from:

[0117] - zinc metal layer,

[0118] - a zinc-doped metal layer,

[0119] -Metallic layer based on zinc alloy.

[0120] According to the present invention, the term "zinc metal layer" refers to a pure zinc metal layer, which may contain a small amount of impurities. In this case, the total mass of zinc is at least 99 mass % based on the mass of the metal layer of zinc.

[0121] According to the invention, the doped zinc layer contains at least 90.0 mass %, at least 95 mass %, at least 96 mass %, at least 97 mass %, at least 98 mass % or at least 99 mass % zinc, based on the mass of the metal layer of zinc.

[0122] The doped zinc layer may 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.

[0123] According to the invention, the layer based on a zinc alloy contains at least 20 mass %, at least 30 mass %, at least 40 mass %, at least 50 mass %, at least 60 mass %, at least 70 mass %, at least 80 mass % or at least 90 mass % of zinc, based on the mass of the zinc-based metal layer.

[0124] The zinc alloy layer may be selected from layers based on zinc and at least one element selected from titanium, nickel, chromium and tin. Examples include binary zinc-titanium alloys, such as Zn2Ti, or ternary zinc-nickel-chromium alloys, such as ZnNiCr.

[0125] The thickness of the zinc or indium based metal layer is 0.2 to 10 nm.

[0126] The thickness of the zinc or indium based metal layer may be:

[0127] - 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

[0128] - 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.

[0129] Preferably, the metal layer based on zinc or indium is located above the metal functional layer based on silver.

[0130] The coating comprises a barrier layer located above and in direct contact with the silver-based metallic functional layer and / or a barrier layer located below and in direct contact with the silver-based metallic functional layer.

[0131] Preferably, the metal layer based on zinc or indium is located above the silver layer and above the barrier layer. In this configuration, the metal layer based on zinc or indium is located above the metallic functional layer based on silver and is separated from this layer by at least one barrier cover layer.

[0132] The barrier layer is selected from the group consisting of metal layers, metal nitride layers, metal oxide layers and metal oxynitride layers based on metals or metal alloys of one or more elements selected from titanium, nickel, chromium, tantalum and niobium, such as Ti, TiN, TiO x , Nb, NbN, Ni, NiN, Cr, CrN, NiCr or NiCrN.

[0133] When these barrier layers are deposited in the form of metals, nitrides or oxynitrides, depending on their thickness and the nature of the layers surrounding them, these layers may undergo partial or complete oxidation, for example during the deposition of the next layer or by oxidation in contact with the underlying layer.

[0134] The barrier layer may be selected from:

[0135] - a metal layer, in particular a metal layer of a nickel-chromium (NiCr) alloy or titanium,

[0136] - A metal nitride layer, in particular titanium nitride or nickel nitride and / or chromium nitride.

[0137] Advantageously, the barrier layer is a nickel-based metal layer. The nickel-based metal barrier layer may contain (before heat treatment) at least 20 mass%, at least 30 mass%, at least 40 mass%, at least 50 mass%, at least 60 mass%, at least 70 mass%, at least 80 mass%, at least 90 mass%, at least 95 mass%, at least 96 mass%, at least 97 mass%, at least 98 mass%, at least 99 mass% or 100 mass% nickel relative to the mass of the nickel-based metal layer.

[0138] The nickel-based metal layer may be selected from:

[0139] - Nickel metal layer,

[0140] - a nickel-doped metal layer,

[0141] -Metallic layer based on nickel alloy.

[0142] The nickel alloy based metal layer may be based on a nickel-chromium alloy.

[0143] Each barrier layer has a thickness of 0.1 to 5.0 nm. The thickness of these barrier layers can be:

[0144] - at least 0.1 nm, at least 0.2 nm, at least 0.5 nm, and / or

[0145] - up to 5.0 nm, up to 4.0 nm, up to 3.0 nm, up to 2.0 nm.

[0146] In an advantageous embodiment, the coating also comprises a crystalline dielectric layer located below and adjacent to the silver layer. These crystalline dielectric layers are typically layers based on zinc oxide.

[0147] The zinc or indium based metal layer may be located:

[0148] - a zinc metal layer on top of the silver-based metallic functional layer in contact with the silver-based metallic functional layer (Ag / Zn sequence),

[0149] - above the metallic functional layer based on silver, a zinc metal layer separated from the metallic functional layer based on silver by at least one barrier cover layer (sequence Ag / / barrier layer / / Zn),

[0150] - above the metallic functional layer based on silver and below and in contact with the conductive oxide layer, a zinc metal layer is separated from the metallic functional layer based on silver by at least one barrier cover layer (sequence Ag / / barrier layer / / Zn / / conductive oxide layer),

[0151] - Below the silver-based metallic functional layer, a zinc metal layer is in contact with the silver-based metallic functional layer (Zn / Ag sequence)

[0152] - underneath the metallic functional layer based on silver, a zinc metal layer is separated from the metallic functional layer based on silver by at least one barrier liner (sequence Zn / / barrier layer / / Ag),

[0153] - a metallic functional layer based on silver below and above and in contact with a crystalline dielectric layer, a metallic layer of zinc in contact with the metallic functional layer based on silver (crystalline layer / Zn / Ag sequence),

[0154] - a metallic functional layer based on silver below and above and in contact with a crystalline dielectric layer, a zinc metal layer separated from the metallic functional layer based on silver by at least one barrier liner (sequence crystalline layer / Zn / / barrier layer / / Ag),

[0155] - beneath a silver-based metallic functional layer and beneath and in contact with a crystalline dielectric layer, the crystalline dielectric layer being in contact with the silver-based metallic functional layer or being separated from the silver-based metallic functional layer by at least one barrier liner (sequence Zn / crystalline layer / / optional barrier layer / / Ag).

[0156] The physical thickness of all layers separating the metallic functional layer based on silver from the metallic layer based on zinc or indium may be 0 to 15.0 nm, or 0 to 10 nm, or 0 to 5 nm, 0.2 to 5 nm, 0.5 to 3 nm, or 0.8 to 1.5 nm.

[0157] The thickness of all layers separating the metallic functional layer based on silver from the metallic layer based on zinc or indium may be:

[0158] - 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

[0159] - less than or equal to 20nm, less than or equal to 15nm, less than or equal to 13nm, less than or equal to 12nm, less than or equal to 11nm, less than or equal to 10nm, less than or equal to 9nm, less than or equal to 8nm, less than or equal to 7nm, less than or equal to 6nm, less than or equal to 5nm, less than or equal to 4nm, less than or equal to 3nm, less than or equal to 2nm, less than or equal to 1.5nm.

[0160] The configuration in which a metal layer based on zinc or indium is located above a metallic functional layer based on silver and is separated from the metallic functional layer based on silver by a barrier cover layer appears to produce the best results.

[0161] In these configurations, a barrier liner may also be used. The use of a barrier liner improves mechanical strength. In this case, the barrier liner is combined with a metal layer based on zinc or indium located above the silver layer and in direct contact with the silver layer or separated from the silver layer by a barrier cover layer.

[0162] According to the invention, “a layer located adjacent to” is understood to mean 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.

[0163] The following embodiments are particularly advantageous because they produce the best results:

[0164] - a metal layer based on zinc or indium is located adjacent to the silver layer, and / or

[0165] - a metal layer based on zinc or indium separated from the silver layer by at least one barrier layer, and / or

[0166] - a metal layer based on zinc or indium is located above the silver layer, and / or

[0167] The coating comprises a barrier layer directly above and in contact with the silver-based metallic functional layer.

[0168] To be effective, the zinc or indium based metal layers must allow the zinc or indium metal elements to diffuse into the silver layer. If these zinc layers are separated from the silver layer by:

[0169] - one or more dielectric layers that are too thick, such as a zinc-tin oxide layer that is too thick, and / or

[0170] - one or more barrier dielectric layers, such as silicon nitride and / or aluminum nitride and / or zirconium nitride layers,

[0171] The diffusion of these zinc or indium metal elements will most likely be greatly reduced or even prevented. The zinc or indium based metal layer then becomes ineffective from the point of view of improving the electrochemical properties.

[0172] The conductive coating may comprise one or more metal layers based on zinc or indium.

[0173] The conductive coating comprises at least one functional layer and at least two dielectric coatings, the dielectric coating comprising at least one dielectric layer, such that each functional layer is placed between two dielectric coatings.

[0174] Within the meaning of the present invention, a "dielectric coating" is understood to mean that within the coating there can be only one layer or a plurality of layers of different materials. A "dielectric coating" according to the invention comprises mainly dielectric layers. However, according to the invention, these layers may also comprise layers of another nature, in particular absorbent layers, for example absorbent metal layers.

[0175] The “same” dielectric coating is considered to be the dielectric coating located at:

[0176] - between the substrate and the first functional layer,

[0177] - Between each silver-based metal functional layer,

[0178] - Over the last functional layer (furthest from the substrate).

[0179] Within the meaning of the present invention, a "dielectric layer" is understood to mean that the material is "non-metallic" from the point of view of its properties, that is to say it is not a metal. In the context of the present invention, this term refers to a material having an n / k ratio equal to or greater than 5 over the entire range of visible wavelengths (380 nm to 780 nm). n represents the real 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, which is the same for n and k.

[0180] The thickness of the dielectric coating corresponds to the sum of the thicknesses of the layers constituting it.

[0181] The coating has a thickness greater than 15 nm, preferably between 15 and 200 nm.

[0182] The dielectric layer of the coating has the following properties alone or in combination:

[0183] - they are deposited by sputtering assisted by a magnetic field,

[0184] - they are chosen from: oxides or nitrides of one or more elements chosen from titanium, silicon, aluminum, zirconium, tin, indium and zinc,

[0185] - They have a thickness greater than 2 nm, preferably between 2 and 100 nm.

[0186] The dielectric coating above the silver-based metallic functional layer must be sufficiently conductive so that the conductive coating retains its electrode function.

[0187] The dielectric coating above the silver-based metallic functional layer comprises at least one conductive oxide layer. The conductive oxide layer is selected from mixed indium and tin oxides, indium oxide doped with tin (ITO "indium tin oxide"), doped zinc oxide such as zinc oxide doped with aluminum (AZO) and / or zinc oxide doped with gallium, doped ruthenium oxide and tin oxide doped with fluorine (SnO2:F).

[0188] Preferred materials are indium tin oxide (ITO) or zinc oxide doped with aluminum and / or gallium.

[0189] 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.

[0190] The sum of the thicknesses 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.

[0191] Preferably, the dielectric coating directly above the silver-based metallic functional layer comprises at least one conductive oxide layer having a thickness of more than 50 nm or 60 nm.

[0192] Preferably, the dielectric coating directly above the silver-based functional layer comprises at least one conductive oxide layer based on aluminum-doped zinc oxide having a thickness of more than 50 nm or 60 nm.

[0193] 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.

[0194] According to the invention, indium tin oxide (ITO) is understood to mean a mixed oxide or mixture obtained from indium (III) oxide (In2O3) and tin (IV) oxide (SnO2), preferably in a mass ratio of 70 to 95% for the first oxide and 5 to 20% for the second oxide. A typical mass ratio is about 90% In2O3 to about 10% SnO2.

[0195] According to the invention, the zinc oxide-based conductive oxide layer may contain at least 50 mass %, at least 60 mass %, at least 70 mass %, at least 80 mass %, at least 90 mass %, at least 95 mass % of zinc relative to the total mass of all elements forming the zinc oxide-based layer except oxygen and nitrogen. For sufficient conductivity, the zinc oxide-based layer is doped with at least one other element, referred to as a "doping element". The zinc oxide-based layer may therefore 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.

[0196] The conductive layer based on doped zinc oxide may contain, relative to the total mass of all elements constituting the layer of zinc oxide other than oxygen and nitrogen:

[0197] - at least 1 mass %, at least 2 mass % or at least 5 mass %, and / or

[0198] - up to 15% by mass or up to 10% by mass of doping elements.

[0199] The dielectric coating below the silver-based metallic functional layer is not necessarily conductive. Advantageously, it may comprise a crystalline layer, also called stabilizing layer or wetting layer. "Stabilizing 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.

[0200] The zinc oxide-based layer may contain at least 50 mass%, at least 60 mass%, at least 70 mass%, at least 80 mass%, at least 90 mass%, at least 95 mass%, at least 96 mass%, at least 97 mass%, at least 98 mass%, at least 99 mass%, or 100 mass% of zinc, compared to the total mass of all elements forming the zinc oxide-based layer except oxygen and nitrogen.

[0201] In order to crystallize correctly by magnetron sputtering, the layer based on zinc oxide advantageously contains at least 80% or even 90% by mass of zinc relative to the total mass of all the elements constituting the zinc oxide layer, except oxygen and nitrogen.

[0202] The zinc oxide-based layer may contain one or more elements selected from the group consisting of aluminum, titanium, niobium, zirconium, magnesium, copper, silver, gold, silicon, molybdenum, nickel, chromium, platinum, indium, tin and hafnium, preferably aluminum.

[0203] The zinc oxide-based layer can optionally be doped with at least one further element, such as aluminum.

[0204] The zinc oxide-based layer comprises, in increasing order of preference, at least 80 mass %, at least 90 mass %, at least 95 mass %, at least 98 mass %, at least 100 mass % oxygen, relative to the total mass of oxygen and nitrogen.

[0205] Preferably, the dielectric coating directly beneath the silver-based metallic functional layer comprises at least one crystalline dielectric layer, in particular based on zinc oxide, optionally doped with at least one further element such as aluminum.

[0206] These zinc oxide layers have the following thicknesses:

[0207] - 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

[0208] - at most 25 nm, at most 15 nm, at most 10 nm or at most 8.0 nm.

[0209] Preferably, the dielectric coating directly below the silver-based functional metal layer comprises at least one dielectric layer having a barrier function. A dielectric layer having a barrier function (hereinafter referred to as a barrier layer) is understood to mean a layer made of a material capable of forming a barrier to the diffusion of oxygen and water from the ambient atmosphere or from the transparent substrate towards the functional layer at high temperatures. Such a dielectric layer is selected from the following layers:

[0210] - Based on silicon and / or aluminum and / or zirconium compounds, selected from oxides such as SiO2, nitrides such as silicon nitride Si3N4 and aluminum nitride AlN, and oxynitrides SiO x N y , optionally doped with at least one other element,

[0211] - based on zinc-tin oxide,

[0212] - Based on titanium oxide.

[0213] These dielectric layers having a barrier function have the following thicknesses in increasing order of preference:

[0214] - less than or equal to 40nm, less than or equal to 30nm, less than or equal to 25nm, and / or

[0215] - greater than or equal to 5 nm, greater than or equal to 10 nm or greater than or equal to 15 nm.

[0216] Preferably, the first dielectric coating comprises:

[0217] - a layer based on a nitride or oxynitride of aluminum and / or silicon and / or zirconium, and / or

[0218] - a layer based on a mixed oxide of zinc and tin, and / or

[0219] - a layer based on a nitride or oxynitride of aluminum and / or silicon and / or zirconium and a dielectric layer based on a mixed oxide of zinc and tin, which is located above the layer based on a nitride or oxynitride of aluminum and / or silicon and / or zirconium, preferably in contact with the layer based on a nitride or oxynitride of aluminum and / or silicon and / or zirconium.

[0220] The layer based on zinc tin oxide may have a thickness of 2 to 30 nm, preferably 5 to 20 nm. The layer based on aluminum and / or silicon and / or zirconium nitride or oxynitride may have a thickness of 2 to 30 nm, preferably 5 to 20 nm. The layer based on zinc tin oxide is located below the layer based on zinc oxide, preferably in contact with it.

[0221] The substrate coated with the conductive coating or the substrate coated only with said coating is intended to undergo a heat treatment. However, the invention also relates to materials which have not been heat treated.

[0222] The conductive coating may not be subjected to a heat treatment at a temperature greater than 500°C, preferably 300°C.

[0223] The coating may have been subjected to a heat treatment at a temperature greater than 300°C, preferably 500°C.

[0224] The heat treatment is selected from annealing (e.g. from "rapid thermal treatment" annealing, such as laser or flash lamp annealing), quenching and / or bending. Rapid thermal annealing is described, for example, in application WO 2008 / 096089. The heat treatment temperature (at the coating) is greater than 300° C., preferably greater than 400° C. and even better still greater than 500° C.

[0225] The substrate to which the coating is applied may be bent or annealed glass.

[0226] The transparent substrate according to the present invention is preferably made of a rigid inorganic material, such as glass, or of a polymer-based organic material (or of a polymer).

[0227] The organic transparent substrate according to the present invention can also be made of polymers and be rigid or flexible. Examples of suitable polymers according to the present invention include in particular:

[0228] - Polyethylene;

[0229] - polyesters, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT) or polyethylene naphthalate (PEN);

[0230] - polyacrylates, such as polymethyl methacrylate (PMMA);

[0231] - polycarbonate;

[0232] - polyurethane;

[0233] - polyamide;

[0234] - polyimide;

[0235] - fluorinated polymers, such as fluorinated esters, for example ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene (ECTFE), fluorinated ethylene propylene copolymers (FEP);

[0236] - photocrosslinkable and / or photopolymerizable resins, such as thiolene, polyurethane, urethane-acrylate, polyester-acrylate resins, and

[0237] -Polythiourethane.

[0238] The substrate is preferably a glass sheet or a glass ceramic sheet.

[0239] The substrate is preferably transparent, colorless (it is thus a clear 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 a glass of the borosilicate or aluminoborosilicate type.

[0240] According to a preferred embodiment, the substrate is made of glass, in particular soda-lime-silica glass, or of a polymeric organic material.

[0241] Advantageously, the substrate has at least one dimension greater than or equal to 1 meter, even 2 meters and even 3 meters.

[0242] The thickness of the substrate generally varies between 0.05 mm and 19 mm. When the substrate is inorganic, its thickness is preferably 0.7 to 9 mm, particularly 2 to 8 mm, or even 4 to 6 mm. The substrate may be flat or curved, or even flexible. When the substrate is organic, its thickness is preferably 1 to 2 mm. Example

[0243] I. Conductive coating

[0244] The conductive coating is deposited onto a transparent glass substrate by cathode sputtering. The glass substrate is a 2.1 mm aluminosilicate glass substrate.

[0245] The functional layer (F) is a layer based on silver (Ag).

[0246] The dielectric coating comprises:

[0247] - a layer based on silicon nitride,

[0248] - a layer based on zinc-tin oxide,

[0249] - a zinc layer doped with aluminum,

[0250] - Indium-Tin layer.

[0251] The barrier layer is selected from titanium, titanium nitride, nickel-chromium and zinc layers.

[0252] The deposition conditions for the layers deposited by sputtering ("magnetron cathode" sputtering) are summarized in Table 1.

[0253] [Table 1]

[0254]

[0255] Table 2 lists the materials and physical thickness in nanometers (unless otherwise stated) of each layer or coating forming the coating, based on their position relative to the substrate supporting the stack (last row at the bottom of the table).

[0256] [Table 2]

[0257]

[0258] The first dielectric coating comprises a SiN / SnZnO / ZnO sequence to prevent diffusion of chemical species from the substrate, reduce surface roughness and optimize silver quality.

[0259] II. Determination of electrochemical properties

[0260] In order to determine the relative conductivity of the conductive coating to mobile electrolyte species such as Li / Li + To study the electrochemical properties of a conductive coating (used as a working electrode) under investigation, voltammetric cycling is performed. To achieve this, the current response resulting from a continuous change in the potential of the conductive coating (used as a working electrode) is measured, on which the electrochemical reaction under investigation takes place.

[0261] Figure 1 and Figure 2 Voltammetric cycling based on a three-electrode setup with a lithium metal counter electrode, a lithium metal reference electrode and a working electrode comprising various conductive coatings is shown. The electrolyte is a LiClO4 / PC solution.

[0262] The voltammograms were taken at a scan rate of 2 mV / s relative to Li / Li + A potential window of 2-4V is generated.

[0263] Figure 3 yes Figure 2 Zoomed in picture at about 3.7V.

[0264] Figure 1 The conductive coatings tested were not heat treated. Figure 2 The conductive coating tested in has been heat treated at 600°C for 8 minutes.

[0265] 1. No heat treatment

[0266] exist Figure 1 For coatings 1 and 7 with titanium or zinc metal barrier layers, respectively, no oxidation reaction was observed between 2 V and 3.4 V. + A slight increase in current density was observed at about 3.4 V, followed by a + The sharp increase is due to the oxidation of metallic Ag to Ag dissolved in the electrolyte. + ions. This indicates that such conductive coatings cannot be used in electrochromic devices. A zinc-based metal layer or a metallic titanium layer alone adjacent to a silver layer showed no positive effect. The presence of redox peaks indicates electrode degradation.

[0267] Coating 6 with NiCr barrier layer shows no redox peak. In the absence of heat treatment, the NiCr based barrier layer alone improves the stability range of the silver based conductive coating.

[0268] The inventive coating 4 according to the invention comprising a barrier layer based on NiCr and a metallic zinc layer does not show a redox peak. An improvement in electrochemical stability can therefore be observed. At higher potentials, an increase in the current is observed. This can be attributed to an increase in the conductivity of the coating due to the contribution of the zinc metal layer.

[0269] 2. After heat treatment

[0270] After heat treatment, redox peaks were observed for coating 1, coating 7, and coating 6. This means that the conductive coating was degraded.

[0271] This phenomenon is particularly pronounced in the case of coating 7, which has only a barrier layer based on zinc metal. An increase in current is observed above 3.4 V, as are redox peaks at 3.6 and 3.7 V. The presence of a zinc metal layer alone does not improve the electrochemical stability of silver after heat treatment.

[0272] For coating 6 with a barrier layer based on NiCr, the positive effect of this layer is weaker in the case of thermal treatment. In fact, although the increase at about 3.4 V is small, a decrease compared to Li + / Li reduction peak at 3.6 V, corresponding to silver degradation.

[0273] The best results were obtained with the inventive conductive coating 4. Neither a redox peak nor a voltage increase was observed at high potentials.

[0274] The combined effect of the barrier layer and the zinc metal layer shows a strong improvement in the electrochemical stability of silver. There is very little current rise above 3.4 V and no redox peaks.

[0275] The effect obtained by the specific combination of the present invention is better than that obtained individually. The zinc metal barrier layer alone cannot improve the electrochemical stability of silver. The NiCr barrier layer cannot prevent the oxidation reduction of the silver layer after heat treatment (above 500°C). Their combination ensures that the silver layer will not degrade.

[0276] Combining the barrier layer with a zinc metal layer capable of diffusing and alloying with silver improves the performance of silver-based coatings relative to Li / Li after heat treatment. + Electrochemical stability above 3.7V.

[0277] The present invention makes it possible to + Silver-based coatings are used in high-contrast electrochromic devices operating in the 2-4V range.

Claims

1. A material comprising a substrate coated with a first conductive coating, the first conductive coating starting from the substrate comprising: - a first dielectric coating, - a metallic functional layer based on silver, a barrier layer located in direct contact with the metallic functional layer based on silver, chosen from: metallic layers based on metals or metal alloys of one or more elements chosen from titanium, nickel, chromium, tantalum and niobium, metal nitride layers, metal oxide layers and metal oxynitride layers, aluminum oxide layers and silicon oxide layers, at least one metallic layer based on zinc or indium, located above or below the metallic functional layer based on silver, in direct contact with said metallic functional layer based on silver 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 said second dielectric coating being greater than 30 nm.

2. The material according to claim 1, characterized in that The barrier layer has a thickness of 0.1 to 5.0 nm.

3. A material according to any one of the preceding claims, characterised in that The barrier layer is selected from the group consisting of a titanium nitride layer, a metal layer based on nickel and / or chromium, a nickel oxide and / or chromium oxide layer, an aluminum oxide layer, and a silicon oxide layer.

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

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

6. Material according to any one of the preceding claims, characterised in that The zinc or indium based metal layer has a thickness of 0.2 to 10 nm.

7. Material according to any one of the preceding claims, characterised in that The second dielectric coating comprises a conductive oxide layer selected from the group consisting of mixed tin and indium oxides, tin-doped indium oxide, doped zinc oxide, doped ruthenium oxide, and fluorine-doped tin oxide.

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

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

10. Material according to any one of the preceding claims, characterised 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 aluminum.

11. Material according to any one of the preceding claims, characterised in that The first dielectric coating comprises: - layers based on nitrides or oxynitrides of silicon, aluminum and / or zirconium, and / or - A layer based on zinc tin oxide.

12. A material according to any one of the preceding claims, characterised in that The conductive coating has been subjected to a heat treatment at a temperature greater than 300°C, preferably 500°C.

13. Material according to the preceding claim, characterised in that The silver-based functional layer contains zinc.

14. An electrochromic system comprising: - a material comprising a substrate coated with a first conductive coating, said first conductive coating comprising, starting from said substrate: - a first dielectric coating, - a functional metal layer comprising a silver-based layer, a barrier layer located in direct contact with the metallic functional layer based on silver, chosen from: metallic layers based on metals or metal alloys of one or more elements chosen from titanium, nickel, chromium, tantalum and niobium, metal nitride layers, metal oxide layers and metal oxynitride layers, aluminum oxide layers and silicon oxide layers, at least one metallic layer based on zinc, located above or below the metallic functional layer based on silver, in direct contact with said metallic functional layer based on silver 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 said second dielectric coating being greater than 30 nm, - a first active layer comprising an electrochromic material, - electrolyte layer, - a second active layer, and - a second transparent conductive coating, - Optional substrate.

Images