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 above and 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 above and in direct contact with the barrier layer, the barrier layer is selected from a metal layer of one or more elements selected from nickel and chromium, such as Ni, Cr, NiCr, and a metal nitride layer of one or more elements selected from titanium, nickel and chromium, such as NiN, CrN, NiCrN, TiN,-a second dielectric coating comprising at least one conductive oxide layer, the sum of the thicknesses of the conductive oxide layers at the second dielectric coating being greater than 40 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 force. 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 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 traditionally 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 phenomenon of coloration / discoloration in the visible range, or more generally a change in the 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. A cathode and an anode electrochromic material pair 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 we consider an electrochromic device comprising a cathodically coloring active layer based on tungsten oxide and an electrolyte layer comprising lithium ions, we observe a colored state at 2.3 V and a low color state at 3.2 V (vs. Li / Li). + ) was observed to be discolored.

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

[0026] Looking at known all-polymer EC systems that include an electrolyte layer that includes 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. These coatings do need to be thick to achieve the desired resistivity values. However, such thick coatings are sensitive to cracking during thermal treatment.

[0033] Conductive coatings with silver-based metallic functional layers offer 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, for silver-based coatings, these reactions result in the reduction of the Ag material, the formation of metal alloys (such as LiAg), or the generation of reducing gases (molecular hydrogen). At high potentials, these reactions result in the reduction of Ag. + 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 metallic layer based on silver,

[0037] - optional barrier layer,

[0038] - A second dielectric layer or coating.

[0039] Cyclic voltammograms were generated 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 / ZnO doped with Al / 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 a potential window between 2 and 4 V.

[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 coloration or fading 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 thick conductive oxide layer results in improved electrochemical stability, particularly 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 metallic functional layer based on silver,

[0047] a barrier layer located above and in direct contact with the metallic functional layer based on silver, said barrier layer being chosen from: a metal layer of one or more elements chosen from nickel and chromium, such as Ni, Cr, NiCr, and a metal nitride layer of one or more elements chosen from titanium, nickel and chromium, such as NiN, CrN, NiCrN, TiN,

[0048] - a second dielectric coating comprising at least one conductive oxide layer, the sum of the thicknesses of the conductive oxide layers being greater than 40 nm, preferably 50 nm.

[0049] 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.

[0050] The invention also relates to a conductive coating comprising a metallic functional layer based on silver, said conductive coating being preferably transparent and having a relative Li / Li + It is electrochemically stable in the potential window of 2 to 4 V. The conductive coating contains:

[0051] - a metallic functional layer based on silver,

[0052] - a barrier layer located above and in direct contact with the silver-based metallic functional layer, the barrier layer being chosen from: a metal layer of one or more elements chosen from nickel and chromium, such as Ni, Cr, NiCr, and a metal nitride layer of one or more elements chosen from titanium, nickel and chromium, such as NiN, CrN, NiCrN, TiN.

[0053] Due to this specific coating structure, transparent conductive coatings can be obtained which have an electrochemical resistance compatible with EC systems and at the same time have highly conductive properties.

[0054] The present invention also relates to a material having the following characteristics:

[0055] - the barrier layer has a thickness of 0.1 to 5.0 nm,

[0056] - the barrier layer is selected from a titanium nitride layer, a nickel-based metal layer and / or a chromium-based metal layer,

[0057] - 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,

[0058] - the second dielectric coating comprises a conductive oxide layer selected from tin-indium mixed oxides or zinc oxide doped with aluminum and / or gallium,

[0059] - the second dielectric coating comprises a conductive oxide layer based on aluminum-doped zinc oxide with a thickness greater than 50 nm,

[0060] - 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,

[0061] - said first dielectric coating comprises a layer based on aluminium and / or zirconium silicon nitride or oxynitride, and / or a layer based on zinc oxide and tin,

[0062] - the substrate is made of glass, in particular soda-lime-silica glass, or of a polymeric organic material,

[0063] - the material further comprises a first active layer comprising an electrochromic material located in contact with the conductive coating,

[0064] - 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,

[0065] - the material further comprises a second active layer in contact with the electrolyte layer,

[0066] - The material further comprises a second conductive coating located in contact with the electrolyte layer.

[0067] The present invention also relates to an electrochromic system comprising:

[0068] - a material according to the invention,

[0069] - a first active layer comprising an electrochromic material,

[0070] - electrolyte layer,

[0071] - a second active layer, and

[0072] - a second transparent conductive coating,

[0073] - Optional substrate.

[0074] 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.

[0075] 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.

[0076] The electrochromic material of the second active layer or counter electrode is preferably based on an oxide of an element selected from tungsten, nickel, iridium, chromium, iron, cobalt or rhodium, or on a mixed oxide of at least two of these elements, in particular a mixed oxide of nickel and tungsten. It is preferably based on nickel oxide or iridium oxide (anodic electrochromic material).

[0077] 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.

[0078] The thickness of the active layer is generally 50 nm to 600 nm, in particular 150 nm to 250 nm.

[0079] 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.

[0080] 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 transparent conductive coatings to provide appropriate power supply.

[0081] The invention also relates to an electrochromic system comprising two substrates held together by a frame.

[0082] 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).

[0083] 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.

[0084] 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.

[0085] 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.

[0086] Unless otherwise mentioned, thicknesses mentioned in this document are physical thicknesses.

[0087] The invention is suitable for single-layer functional coatings based on silver. This solution is also suitable for multi-layer functional coatings based on silver, in particular coatings with two or three functional layers. The coating comprises at least one or only one metallic functional layer based on silver.

[0088] The metallic functional layer based on silver contains 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.

[0089] Preferably, the silver-based metallic functional layer contains less than 1.0 wt. % of metal other than silver, relative to the weight of the silver-based metallic functional layer, before the heat treatment.

[0090] The term "metal layer" refers to a layer containing no more than 30%, 20% or 10% of oxygen and / or nitrogen in the layer in terms of atomic percentage.

[0091] The purpose of the barrier layer is to improve the electrochemical properties of the silver layer.

[0092] When these barrier layers are deposited in the form of metals or nitrides, 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.

[0093] Advantageously, the barrier layer is a nickel-based metal layer. The nickel-based metal barrier layer may contain (before heat treatment) at least 20 wt. %, at least 30 wt. %, at least 40 wt. %, at least 50 wt. %, at least 60 wt. %, at least 70 wt. %, at least 80 wt. %, at least 90 wt. %, at least 95 wt. %, at least 96 wt. %, at least 97 wt. %, at least 98 wt. %, at least 99 wt. % or 100 wt. % nickel relative to the weight of the nickel-based metal layer.

[0094] The nickel-based metal layer may be selected from:

[0095] - Nickel metal layer,

[0096] - a nickel-doped metal layer,

[0097] -Metallic layer based on nickel alloy.

[0098] The nickel alloy based metal layer may be based on a nickel-chromium alloy.

[0099] The barrier layer may also advantageously be a titanium nitride layer.

[0100] Each barrier layer has a thickness of 0.1 to 5.0 nm. The thickness of these barrier layers can be:

[0101] - at least 0.1 nm, at least 0.2 nm, at least 0.5 nm, and / or

[0102] - at most 5.0 nm, at most 4.0 nm, at most 3.0 nm, or at most 2.0 nm.

[0103] 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.

[0104] 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.

[0105] The “same” dielectric layer is considered to be a dielectric layer located at:

[0106] - between the substrate and the first functional layer,

[0107] - Between each silver-based metal functional layer,

[0108] - Over the last functional layer (furthest from the substrate).

[0109] 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.

[0110] The thickness of the dielectric coating corresponds to the sum of the thicknesses of the layers constituting it.

[0111] The coating has a thickness greater than 15 nm, preferably between 15 and 200 nm.

[0112] The dielectric layer of the coating has the following properties alone or in combination:

[0113] - they are deposited by sputtering assisted by a magnetic field,

[0114] - they are chosen from: oxides or nitrides of one or more elements chosen from titanium, silicon, aluminum, zirconium, tin, indium and zinc,

[0115] - They have a thickness greater than 2 nm, preferably between 2 and 100 nm.

[0116] The dielectric coating above the silver-based metallic functional layer must be sufficiently conductive so that the conductive coating retains its electrode function.

[0117] 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).

[0118] Preferably, indium tin oxide (ITO) or zinc oxide doped with aluminum and / or gallium is used.

[0119] 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.

[0120] 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.

[0121] Preferably, the dielectric coating directly above the silver-based functional layer comprises at least one conductive oxide layer thicker than 50 nm or 60 nm.

[0122] Preferably, the dielectric coating directly above the silver-based functional layer comprises at least one conductive oxide layer based on aluminum-doped zinc oxide which is thicker than 50 nm or 60 nm.

[0123] The combination of a barrier layer according to the invention with a thick conductive oxide layer based on doped zinc oxide gives the best results in terms of electrochemical stability.

[0124] In one embodiment, the dielectric coating may include at least two layers - an aluminum-doped zinc oxide layer and a mixed indium tin oxide (ITO) layer.

[0125] According to the invention, indium tin oxide (ITO) is 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.

[0126] According to the present 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 %, or at least 95 mass % of zinc compared to the 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.

[0127] The doped zinc oxide-based conductive layer may contain, relative to the total weight of all elements forming the zinc oxide-based layer except oxygen and nitrogen:

[0128] - at least 1 wt. %, at least 2 wt. % or at least 5 wt. %, and / or

[0129] - up to 15% by weight or up to 10% by weight of doping elements.

[0130] The dielectric coating below the silver-based metallic functional layer does not need to be 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] The zinc oxide-based layer can optionally be doped with at least one further element, such as aluminum.

[0135] The zinc oxide-based layer comprises, in increasing order of preference, at least 80% by weight, at least 90% by weight, at least 95% by weight, at least 98% by weight, at least 100% by weight of oxygen, relative to the total weight of oxygen and nitrogen.

[0136] 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.

[0137] These zinc oxide layers have the following thicknesses:

[0138] - at least 1.0 nm, at least 2.0 nm, at least 3.0 nm, at least 4.0 nm, at least 5.0 nm, and / or

[0139] - at most 25 nm, at most 10 nm or at most 8.0 nm.

[0140] Preferably, the dielectric coating directly below the silver-based metallic functional 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:

[0141] - 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 oxides SiO x N y , optionally doped with at least one other element,

[0142] - based on zinc-tin oxide,

[0143] - Based on titanium oxide.

[0144] Preferably, the first dielectric coating comprises at least one dielectric layer based on:

[0145] - nitrides or oxynitrides of aluminium and / or silicon and / or zirconium, or

[0146] - mixed oxides of zinc and tin, or

[0147] -Titanium oxide.

[0148] Preferably, the first dielectric coating comprises:

[0149] - a layer based on a nitride or oxynitride of aluminum and / or silicon and / or zirconium, and / or

[0150] - a layer based on a mixed oxide of zinc and tin, and / or

[0151] - 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.

[0152] The zinc tin oxide based layer is located below the oxide based layer, preferably in contact therewith.

[0153] The thicknesses of these dielectric layers having a barrier function are, in ascending order of preference:

[0154] - less than or equal to 40nm, less than or equal to 30nm, less than or equal to 25nm, and / or

[0155] - greater than or equal to 5 nm, greater than or equal to 10 nm or greater than or equal to 15 nm.

[0156] The substrate coated with the conductive coating or the substrate coated with said coating alone may not be subjected to heat treatment. The present invention relates to materials which have not been heat treated or to materials which have been heat treated.

[0157] The conductive coating may not be subjected to a heat treatment at a temperature greater than 500°C, preferably 300°C.

[0158] The coating may have to undergo a heat treatment at a temperature above 300° C., preferably 500° C. In this case, the heat treatment is selected from annealing (for example by rapid thermal annealing, such as laser annealing 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.

[0159] The substrate to which the coating is applied may be bent or annealed glass.

[0160] 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).

[0161] The organic transparent substrate according to the invention can also be made of polymers and be rigid or flexible. Examples of suitable polymers according to the invention include in particular:

[0162] - Polyethylene;

[0163] - Polyesters, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN);

[0164] - polyacrylates, such as polymethyl methacrylate (PMMA);

[0165] - polycarbonate;

[0166] - polyurethane;

[0167] - polyamide;

[0168] - polyimide;

[0169] - fluorinated polymers, such as fluorinated esters, for example ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene (ECTFE), fluorinated ethylene propylene copolymers (FEP);

[0170] - photocrosslinkable and / or photopolymerizable resins, such as thiolenes, polyurethanes, urethane-acrylates, polyester-acrylates, and

[0171] -Polythiourethane.

[0172] The substrate is preferably a glass sheet or a glass ceramic sheet.

[0173] 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.

[0174] According to a preferred embodiment, the substrate is made of glass, in particular soda-lime-silica glass, or of a polymeric organic material.

[0175] Advantageously, the substrate has at least one dimension greater than or equal to 1 meter, or even 2 meters, or even 3 meters.

[0176] The thickness of the substrate is generally 0.05 mm to 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 can be flat or curved, or even flexible. When the substrate is organic, its thickness is preferably 1 to 2 mm. Example

[0177] I. Conductive coating

[0178] The conductive coating is deposited onto a transparent glass substrate by cathode sputtering. The glass substrate is a 2.1 mm aluminosilicate glass substrate.

[0179] The functional layer (F) is a silver-based metallic layer.

[0180] The dielectric coating comprises:

[0181] - Silicon nitride based coatings,

[0182] - a zinc-tin oxide layer,

[0183] - a zinc layer doped with aluminum,

[0184] - Indium-Tin layer.

[0185] The barrier layer is selected from titanium, titanium nitride, nickel-chromium and zinc layers.

[0186] The deposition conditions for the layers deposited by sputtering ("magnetron cathode" sputtering) are summarized in Table 1.

[0187] [Table 1]

[0188]

[0189] Table 2 lists the materials forming each layer or coating of the coating as a function of their position relative to the substrate bearing the stack (last row at the bottom of the table).

[0190] [Table 2]

[0191]

[0192] 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.

[0193] These coatings have not been heat treated at elevated temperatures.

[0194] II. Determination of electrochemical properties

[0195] 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.

[0196] The figures show voltammetric cycles based on a three-electrode setup with a lithium metal counter electrode, a lithium metal reference electrode and a working electrode with various conductive coatings. The electrolyte was a LiClO4 / PC solution.

[0197] The voltammograms were taken at a scan rate of 2 mV / s relative to Li / Li + A potential window of 2 to 4 V is generated.

[0198] 1. Properties of the dielectric layer of the upper dielectric coating

[0199] Conductive coatings 1, 2 and 3 differ in the choice of the conductive oxide layer constituting the upper dielectric coating.

[0200] Figure 1The conductive coating tested in the experiment was not heat treated. In this figure, the degradation of the coating is observed, with oxidation peaks and reduction peaks, as well as the relative Li / Li + The current rises above 3.4V.

[0201] However, when a conductive oxide layer based on aluminum-doped zinc oxide is used, this phenomenon is less obvious. This is reflected in the fact that the peak of coating 1 is lower than the peak of coating 2 or coating 3. Therefore, the conductive coating of the present invention preferably comprises at least one aluminum-doped zinc oxide layer having a thickness of more than 40 nm or more than 50 nm.

[0202] 2. Properties of the barrier layer

[0203] 1. No heat treatment

[0204] Coatings 4 and 5 differ from coating 3 in the nature of the barrier layer (TiN and NiCr vs. Ti, respectively). Figure 2 The voltammetric cycles of the three coatings without heat treatment are shown.

[0205] Changing the metal barrier from Ti to TiN or NiCr has a strong effect on the electrochemical window of silver. + The current rise above 3.4 V is much lower and is no longer observed with respect to Li / Li + The oxidation or reduction peak is at about 3.6-3.7 V. The electrode coating is related to Li / Li + Compatible with EC devices operating in the 2-4V range.

[0206] The NiCr and TiN layers act as an effective shield against any degradation of the silver layer that may occur during subsequent layer deposition (cathodic sputtering), high temperature annealing and / or subsequent electrochemical reactions.

[0207] The barrier layers of coating 6, coating 7 and coating 1 (NiCr, Zn and Ti respectively) are of different nature. Figure 3 The voltammetric cycles of the three coatings are shown.

[0208] No heat treatment was performed.

[0209] The presence of a barrier metal layer based on zinc or titanium near the silver layer did not show a positive effect. The presence of redox peaks indicates electrode degradation.

[0210] Coating 6 has good electrochemical stability. The current rise is very small above 3.4 V and there is no redox peak.

[0211] The present invention enables the use of silver-based coatings in high contrast electrochromic devices operating in the 2-4 V range relative to Li / Li+.

[0212] 2. After heat treatment

[0213] After heat treatment at 600°C for 8 minutes, redox peaks were observed for coatings 1, 7, and 6. Figure 4 The voltammetric cycles of the three coatings after heat treatment are shown.

[0214] This phenomenon is particularly pronounced in the case of coating 7 comprising a metallic zinc barrier layer. 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 metallic zinc layer alone does not improve the electrochemical stability of silver after heat treatment.

[0215] In the case of the coating 6 with the NiCr-based barrier layer, the positive influence of this layer is weaker in the case of heat treatment.

Claims

1. A material comprising a substrate coated with a first coating, the first coating, starting from the substrate, comprising: - a first dielectric coating, - a metallic functional layer based on silver, a barrier layer located above and in direct contact with the silver-based metallic functional layer, the barrier layer being chosen from: a metal layer of one or more elements chosen from nickel and chromium, such as Ni, Cr, NiCr, and a metal nitride layer of one or more elements chosen from titanium, nickel and chromium, such as NiN, CrN, NiCrN, TiN, - 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 40 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 a titanium nitride layer, a nickel-based metal layer and / or a chromium-based metal layer.

4. 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, indium tin oxide, doped zinc oxide, doped ruthenium oxide, and fluorine doped tin oxide.

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

6. 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.

7. 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.

8. Material according to the preceding claim, characterised in that The crystalline dielectric layer, in particular based on zinc oxide, has a thickness of 2 to 15 nm.

9. Material according to any one of the preceding claims, characterised in that The first dielectric coating comprises: - layers based on aluminum and / or zirconium silicon nitride or oxynitride, and / or - Zinc-tin oxide layer.

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

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

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