Electrochromic glazing

Abstract

The invention relates to a material comprising a substrate coated with a first conductive coating comprising, starting from the substrate: - a first dielectric coating; - a silver-based metal functional functional layer; - a blocking layer located above and immediately in contact with a silver-based metal functional layer, said blocking layer being chosen from metal layers of one or more elements chosen from nickel and chromium such as Ni, Cr, NiCr, and metal nitride layers 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 of said second dielectric coating being greater than 40 nm.

Description

[0001] Title: ELECTROCHROME GLAZING

[0002] The present invention relates to the field of electrochromic (EC) glazing. The invention relates in particular to an electroconductive coating for an electrochromic device comprising a silver-based metal functional layer having improved electrochemical properties.

[0003] 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 electrical voltage, thus making it possible to obtain easily adjustable electrically controlled coatings.

[0004] Electrochromic devices comprise, in a known manner, an electrochromic system comprising a succession of at least five layered elements essential to the operation of the device, i.e. to the reversible change of color following the application of an appropriate electrical supply. These five layered elements are as follows:

[0005] - a first transparent electroconductive coating,

[0006] - a first active layer acting as an electrode,

[0007] - a layer of electrolyte,

[0008] - a second active layer acting as a counter electrode, and

[0009] - a second transparent electrically conductive coating.

[0010] At least one active layer is based on an electrochromic material.

[0011] These five layered elements are generally in contact with one or two transparent substrate(s).

[0012] Electrochromic systems are divided into three categories:

[0013] - the so-called “all-solid” inorganic technology,

[0014] - so-called “hybrid” technology,

[0015] - the so-called “all-polymer” technology.

[0016] □In “all-solid” electrochromic systems, all layers are made of inorganic solid materials. These systems may comprise a single substrate. Examples of all-solid EC systems are described in patent applications EP-867 752, EP-831 360, WO 00 / 57243 and WO 00 / 71777.

[0017] Hybrid electrochromic systems comprise inorganic active layers that frame an electrolyte layer based on an ionically conductive polymer. These systems traditionally comprise two substrates framing the electrochromic system. Examples of hybrid EC systems are described in patent applications EP-382 623, EP-518 754 and EP-532 408.

[0018] In "all-polymer" electrochromic systems, the active layers and the electrolyte layer are polymer-based. The phenomenon of coloration / discoloration in the visible range or of changes in optical properties more generally, results from a transfer of charge (ions / electrons) between the two active layers.

[0019] An active layer based on an electrochromic material is able to reversibly insert ions. When ions migrate to this layer, its optical properties change and it reversibly switches from a bleached state to a colored state. The other active layer can also be based on an electrochromic material.

[0020] Inorganic electrochromic materials are overwhelmingly transition metal oxides, grouped into two families: cathodic colored oxides, such as tungsten oxide WO3, which are colored in the reduced state, and anodic colored oxides, such as iridium oxide (IrOx) and nickel oxide (NIOx), which are colored in the oxidized state. Cathodic and anodic electrochromic material pairs are generally chosen, for example, with a cathodic material that is colored in the inserted state in association with an anodic material, which is discolored in the inserted state.

[0021] The electrolyte layer must have good ionic conductivity and be electronically insulating. The electrolytes of the electrochromic system ensure the passage of mobile ions within their range of electrochemical stability. In theory, all monovalent ions, such as H+, Li-»-, Na+, K+, Ag+, divalent ions such as Zn 2+ and trivalents such as Al 3+can be used. Lithium, alkali or hydrogen salts are particularly suitable.

[0022] For example, for an active layer of tungsten oxide (WO3) in contact with an ionically conductive lithium electrolyte layer, there is a transfer of Li ions + between the electrodes when a voltage is applied. The following electrochemical reaction is observed at the cathode: W 6 l O 2 '3(transparent) + x Li + +x e- — > Li W 6+ i. x W 5+ x O 2 -3(blue).

[0023] The voltage ranges that allow the best contrast between the colored and discolored states to be obtained can be determined by voltammetry. Voltammetric cycles or curves or voltamgrams (j = f(V)) consist of following the variation of the current density j in the scanned potential interval. The study of current density variations is significant for the electrochemical behavior of materials. The coloring potentials (Vcoloration), the discoloration potentials (Vdiscoloration) of the material corresponding to oxidation reactions in the anodic part (Q > 0) or reduction reactions in the cathodic part of the curve (j < 0) as well as the stability ranges can be deduced directly from these curves.

[0024] If we consider an electrochromic device comprising a cathodic 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 discolored state at 3.2 V (vs Li / Li+).

[0025] Considering an electrochromic device comprising an anodic coloring active layer based on nickel oxide and an electrolyte layer comprising lithium ions, the oxidation potential associated with the de-insertion of lithium ions is approximately 4 V while the decolorization voltage can be adjusted by doping the nickel oxide between 1 V and 2.5 V.

[0026] Considering known all-polymer EC systems comprising an electrolyte layer comprising lithium ions, the voltage range from a less transparent state to a more transparent state is between 2V and 4V vs Li / Li-»-.

[0027] Therefore, for these EC systems, the reactions allowing coloring and bleaching occur in a potential window between 1V and 4V. The materials constituting the different layered elements of the electrochromic system must have electrochemical stability ranges greater than the potential windows necessary to obtain the coloring / bleaching phenomena.

[0028] The "voltage stability range" of a material is the potential range to which a material can be exposed without undergoing an oxidation or reduction reaction.

[0029] When a material is subject to an electrochemical potential outside its stability range and in the presence of the corresponding ions, an oxidation-reduction reaction occurs.

[0030] In the case of electrochromic systems, the electroconductive coatings are exposed to the electrochemical potentials of the active materials with which they are in contact. This means that the electroconductive coatings of the electrochromic device must be stable in the potential window 2V to 4V, or even 1V to 4V vs Li / Li+. The electroconductive coatings must therefore have a range of electrochemical stability relative to the Li+ / Li couple preferably between 1V and 4V. The materials constituting these conductive coatings must not undergo any redox reaction in this voltage range.

[0031] Known electrically conductive coatings include conductive functional layers based on transparent conductive oxide such as indium and tin layers or fluorine-doped tin layers or metallic functional layers, especially based on silver.

[0032] Electroconductive coatings based on conductive oxide layers, although they exhibit excellent electrochemical stability, do not exhibit sufficient conductive properties at high light transmission (>80%). This results in inhomogeneous switching and / or a switching speed that decreases as the surface area of ​​the EC system increases. Finally, in some applications such as automotive applications, additional processing steps such as quenching or bending steps are sometimes required. These additional steps are likely to alter conductive oxide coatings. Indeed, these coatings must be thick to achieve the desired resistivity values. However, these thick coatings are susceptible to cracking during heat treatment.

[0033] Conductive coatings comprising a silver-based metallic functional layer exhibit superior electrical conductivity and high transparency. However, the low electrochemical stability of the silver functional layer limits the use of this type of conductive coating in electrochromic devices. Silver-based conductive coatings undergo, in particular, oxidation-reduction reactions with respect to the Li / Li+ couple in the 1V-4V range. At low potential, these reactions result in a reduction of the Ag material, the formation of a metallic alloy (such as LiAg), or the production of reduced gas (dihydrogen) for a silver-based layer. At high potential, these reactions result in oxidation of the Ag-i- material, the formation of oxide (AgO) and / or the production of oxidized gas (dioxygen). In the context of high-potential reactions, we can also speak of "corrosion" of the materials.

[0034] Known electrically conductive coatings of this type include:

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

[0036] - a silver-based metallic layer,

[0037] - possibly a blocking layer,

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

[0039] Cyclic voltammograms were performed to determine the voltage stability range of these electroconductive coatings using a three-electrode setup with a lithium metal counter electrode, a lithium metal reference electrode, and a working electrode comprising the electroconductive coating to be tested. The electrolyte is composed of a LiCIO4 / PC solution. The working electrode comprises a 2 mm glass substrate covered with a known silver-based electroconductive coating comprising, starting from the substrate, the sequence (SiN / SnZnO / ZnO doped Al / Ag). The voltammogram was performed in the potential window of 2 to 4 V versus LI / LÎ+- at a scan rate of 2 mV / s.

[0040] No oxidation reaction is observed between 2 V and 3.4 V. A slight increase in current density is observed around 3.4 V vs Li / Li +, followed by a sharp increase around 3.7 V vs Li / Li +. This sharp increase is attributable to the oxidation of metallic Ag to Ag ions + which dissolve in the electrolyte. This demonstrates that such conductive coatings cannot be used in electrochromic devices unless the accessible contrast of the EC device is limited by imposing potentials lower than 3.7 V. In this case, no complete discoloration or coloring is obtained.

[0041] In order to benefit from the improved optical and conductive properties of silver-based electroconductive coatings in electrochromic devices, it is necessary to extend their electrochemical stability range. The present invention relates to an electroconductive coating comprising a silver-based metal functional layer having improved electrochemical stability. The coating of the invention is particularly suitable for use in electrochromic devices.

[0042] The applicant has discovered that the use of certain blocking layers in combination with a thick conductive oxide layer allows for improved electrochemical stability, particularly around 3.7V vs Li / Li-i-. This improvement in electrochemical stability makes the use of the agent-based conductive coating compatible for EC applications.

[0043] The invention relates to a material comprising a substrate coated with a first conductive coating comprising, starting from the substrate:

[0044] - a first dielectric coating,

[0045] - a silver-based metallic functional layer,

[0046] - a blocking layer located above and immediately in contact with a silver-based functional metal layer, chosen from metal layers of one or more elements chosen from nickel and chromium such as Ni, Cr, NiCr, and metal nitride layers of one or more elements chosen from titanium, nickel, chromium such as NiN, CrN, NiCrN, TiN,

[0047] - a second dielectric coating comprising at least one conductive oxide layer where the sum of the thicknesses of the conductive oxide layers is greater than 40 nm, preferably 50 nm.

[0048] The invention allows to increase the stability range of the silver-based electroconductive coating above 3.7 V compared to LI / LI+.

[0049] The invention also relates to a conductive coating comprising a silver-based metallic functional layer, preferably transparent, electrochemically stable in the potential window of 2 to 4 V with respect to Li / Li + . The conductive coating comprises:

[0050] - a silver-based metallic functional layer,

[0051] - a blocking layer located above and immediately in contact with a silver-based functional metal layer, chosen from metal layers of one or more elements chosen from nickel and chromium such as Ni, Cr, NiCr, and metal nitride layers of one or more elements chosen from titanium, nickel, chromium such as NiN, CrN, NiCrN, TiN.

[0052] Thanks to this particular coating structure, it is possible to obtain a transparent conductive coating having an electrochemical resistance compatible with EC systems while having high electrical conductivity properties. The invention also relates to a material having the following characteristic(s):

[0053] - the blocking layer has a thickness between 0.1 and 5.0 nm,

[0054] - the blocking layer is chosen from a layer of titanium nitride, metallic layers based on nickel and / or chromium,

[0055] - the blocking 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,

[0056] - the second dielectric coating comprises a layer of conductive oxide chosen from mixed tin and indium oxide or zinc oxide doped with aluminum and / or gallium,

[0057] - the second dielectric coating comprises a conductive oxide layer based on aluminum-doped zinc oxide with a thickness greater than 50 nm,

[0058] - the first dielectric coating comprises at least one crystallized dielectric layer, in particular based on zinc oxide, possibly doped with at least one other element, such as aluminum,

[0059] - the first dielectric coating comprises a layer based on silicon nitride or oxynitride of aluminum and / or zirconium, and / or a layer based on zinc and tin oxide,

[0060] - the substrate is made of glass, in particular soda-lime-silica or polymeric organic material,

[0061] - the material further comprises a first active layer comprising an electrochromic material located in contact with the electroconductive coating,

[0062] - the material further comprises an electrolyte layer located in contact with the first active layer comprising an electrochromic material, preferably the electrolyte is a lithium ion-conducting electrolyte,

[0063] - the material further comprises a second active layer located in contact with the electrolyte layer,

[0064] - the material further comprises a second electrically conductive coating located in contact with the electrolyte layer.

[0065] The invention also relates to an electrochromic system comprising:

[0066] - a material according to the invention,

[0067] - a first active layer comprising an electrochromic material,

[0068] - an electrolyte layer,

[0069] - a second active layer and

[0070] - a second transparent electroconductive coating,

[0071] - possibly a substrate.

[0072] The electrochromic material of the active layers can be based on mineral material such as tungsten oxide, nickel oxide, iridium oxide, cerium oxide or organic material such as electronically conductive polymers such as polyaniline or (poly(3,4-ethylenedioxythiophene)) (PEDOT) or Prussian blue. These materials can insert cations, including protons or lithium ions.

[0073] The electrochromic material of the first active layer may be based on an oxide of an element chosen from tungsten, nickel, iridium, chromium, iron, cobalt, rhodium, or based on a mixed oxide of at least two of these elements, in particular the mixed oxide of nickel and tungsten. It is preferably based on tungsten oxide.

[0074] The electrochromic material of the second active layer or counter-electrode is preferably based on an oxide of an element chosen from tungsten, nickel, iridium, chromium, iron, cobalt, rhodium, or based on a mixed oxide of at least two of these elements, in particular the mixed oxide of nickel and tungsten. It is preferably based on nickel oxide or iridium oxide (anodic electrochromic material).

[0075] If the electrochromic material of the first active layer is tungsten oxide, i.e. a cathodic electrochromic material, whose colored state corresponds to the most reduced state, an anodic electrochromic material based on nickel or iridium oxide can be used, for example, for the counter-electrode. This can in particular be a layer of mixed vanadium and tungsten oxide or mixed nickel and tungsten oxide.

[0076] The thickness of the active layers is generally between 50 nm and 600 nm, in particular between 150 nm and 250 nm.

[0077] The thickness of the electrolyte layer may be between 1 nm and 1 mm. When the electrolyte layer is made of inorganic material, its thickness is preferably between 1 and 300 nm, between 1 and 50 nm or between 1 and 10 nm. When the electrolyte layer is made of polymeric material, its thickness is preferably between 100 and 800 pm or between 100 and 500 pm.

[0078] The two electrically conductive coatings must be connected to respective power supply connectors. These connectors, for example bus bar and wires, are respectively brought into contact with the transparent conductive coatings to bring the appropriate power supply.

[0079] The invention also relates to an electrochromic system comprising two substrates made integral by means of a chassis or frame.

[0080] Throughout the description, the substrate according to the invention is considered to be laid horizontally. The electrically conductive coating is deposited above the substrate. The meaning of the expressions "above" and "below" and "lower" and "upper" is to be considered in relation to this orientation. In the absence of a specific stipulation, the expressions "above" and "below" do not necessarily mean that two layers and / or coatings are arranged in contact with each other. When it is specified that a layer is deposited "in contact" with another layer or a coating, this means that there cannot be one (or more) layer(s) interposed between these two layers (or layer and coating).

[0081] All the luminous characteristics described are obtained according to the principles and methods of the European standard EN 410 relating to the determination of the luminous and solar characteristics of glazing used in glass for construction.

[0082] The preferred characteristics which appear in the remainder of the description are applicable both to the material according to the invention and, where appropriate, to the glazing or to the system according to the invention.

[0083] The electrically conductive coating is deposited by magnetic field-assisted sputtering (magnetron process). In this advantageous embodiment, all layers of the coating are deposited by magnetic field-assisted sputtering.

[0084] Unless otherwise stated, the thicknesses referred to in this document are physical thicknesses.

[0085] The present invention is suitable for a single-layer silver-based functional coating. The solution of the invention is also suitable for a multi-layer silver-based functional coating, in particular two or three functional layers. The coating comprises at least one or a single silver-based functional metal layer.

[0086] The silver-based functional metal layer, before or after heat treatment, comprises at least 95.0%, preferably at least 96.5% and better still at least 98.0% by mass of silver relative to the mass of the functional layer.

[0087] Preferably, the silver-based functional metal layer before heat treatment comprises less than 1.0% by mass of metals other than silver relative to the mass of the silver-based functional metal layer.

[0088] “Metal layer” means a layer comprising not more than 30%, 20% or 10% oxygen and / or nitrogen by atomic percentage in the layer.

[0089] The purpose of blocking layers is to improve the electrochemical properties of the silver layers.

[0090] When these blocking layers are deposited in metallic or nitrided form, these layers can undergo partial or total oxidation depending on their thickness and the nature of the layers surrounding them, for example, at the time of deposition of the next layer or by oxidation in contact with the underlying layer.

[0091] Advantageously, the blocking layers are nickel-based metal layers. The nickel-based metal blocking layers may comprise, (before heat treatment), at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% by mass of nickel relative to the mass of the nickel-based metal layer.

[0092] Nickel-based metal layers can be chosen from:

[0093] - the metallic layers of nickel,

[0094] - doped nickel metal layers,

[0095] - metallic layers based on nickel alloy.

[0096] Nickel alloy based metal layers can be based on nickel and chromium alloy.

[0097] The blocking layers can also advantageously be titanium nitride layers.

[0098] Each blocking layer has a thickness between 0.1 and 5.0 nm. The thickness of these blocking layers can be:

[0099] - at least 0.1 nm, at least 0.2 nm, at least 0.5 nm and / or

[0100] - not more than 5.0 nm, not more than 4.0 nm, not more than 3.0 nm, not more than 2.0 nm.

[0101] The electrically conductive coating comprises at least one functional layer and at least two dielectric coatings comprising at least one dielectric layer, such that each functional layer is disposed between two dielectric coatings.

[0102] By "dielectric coating" within the meaning of the present invention, it is understood that there may be a single layer or several layers of different materials inside the coating. A "dielectric coating" according to the invention mainly comprises dielectric layers. However, according to the invention these coatings may also comprise layers of other nature, in particular absorbent layers, for example metallic ones.

[0103] A "same" dielectric coating is considered to be located: between the substrate and the first functional layer, between each silver-based functional metal layer, above the last functional layer (furthest from the substrate).

[0104] By "dielectric layer" for the purposes of the present invention, it is to be understood that from the point of view of its nature, the material is "non-metallic", i.e. is not a metal. In the context of the invention, this term designates a material having an n / k ratio over the entire visible wavelength range (from 380 nm to 780 nm) equal to or greater than 5. n designates 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 being calculated at a given wavelength identical for n and for k.

[0105] The thickness of a dielectric coating corresponds to the sum of the thicknesses of the layers constituting it. The coatings have a thickness greater than 15 nm, preferably between 15 and 200 nm.

[0106] The dielectric layers of the coatings have the following characteristics alone or in combination: they are deposited by magnetic field-assisted sputtering, they are chosen from oxides or nitrides of one or more elements chosen from titanium, silicon, aluminum, zirconium, tin, indium and zinc, they have a thickness greater than 2 nm, preferably between 2 and 100 nm.

[0107] The dielectric coating above the silver-based metallic functional layer must be sufficiently conductive for the electrically conductive coating to retain its electrode function.

[0108] The dielectric coating located above the silver-based metal functional layer comprises at least one conductive oxide layer. The conductive oxide layers are chosen from mixed tin and indium oxide, tin-doped indium oxide (ITO “Indium Tin Oxide”), doped zinc oxide such as zinc oxide doped in particular with aluminum (AZO) and / or gallium, doped ruthenium oxide and fluorine-doped tin oxide (SnO2:F).

[0109] Preferably, mixed indium tin oxide (ITO) or zinc oxide doped with aluminum and / or gallium are used.

[0110] The sum of the thicknesses of all conductive oxide layers located in the dielectric coating directly above the silver-based functional layer is greater than 50 nm or greater than 60 nm.

[0111] The sum of the thicknesses of all conductive oxide layers located 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.

[0112] Preferably, the dielectric coating located directly above the silver-based functional layer comprises at least one conductive oxide layer with a thickness greater than 50 nm or 60 nm.

[0113] Preferably, the dielectric coating located directly above the silver-based functional layer comprises at least one conductive oxide layer based on aluminum-doped zinc oxide with a thickness greater than 50 nm or 60 nm. The combination of a blocking 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.

[0114] According to one embodiment, the dielectric coating may comprise at least two layers, a layer of aluminum-doped zinc oxide and a layer of mixed indium tin oxide (ITO). According to the invention, indium-tin oxide (or tin-doped indium oxide or ITO for the English term: Indium tin oxide) means a mixed oxide or a mixture obtained from the oxides of indium(III) (In2O3) and tin(IV) (SnO2), preferably in mass proportions of between 70 and 95% for the first oxide and 5 to 20% for the second oxide. A typical mass proportion is approximately 90% by mass of In2O3 for approximately 10% by mass of SnO2.

[0115] According to the invention, the conductive oxide layers based on zinc oxide may comprise at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95% by mass of zinc relative to the total mass of all the elements constituting the zinc oxide layer excluding oxygen and nitrogen. To be sufficiently conductive, the zinc oxide layers are doped using at least one other element called a "doping element". The zinc oxide layers may therefore comprise one or more doping elements chosen from aluminum, titanium, niobium, zirconium, magnesium, copper, silver, gold, silicon, molybdenum, nickel, chromium, platinum, indium, tin and hafnium, preferably aluminum.

[0116] Conductive layers based on doped zinc oxide may include:

[0117] - at least 1%, at least 2% or at least 5%, and / or

[0118] - at most 15% or at most 10%, by mass of doping elements relative to the total mass of all the elements constituting the zinc oxide-based layer excluding oxygen and nitrogen.

[0119] The dielectric coating located below the silver-based metallic functional layer does not necessarily have to be conductive. Advantageously, it may comprise a crystallized layer also called a stabilizing or wetting layer. A 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.

[0120] The zinc oxide-based layers may comprise at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% by mass of zinc relative to the total mass of all the elements constituting the zinc oxide-based layer excluding oxygen and nitrogen.

[0121] To be correctly crystallized by sputtering deposition, the zinc oxide-based layers advantageously comprise at least 80%, or even at least 90% by mass of zinc relative to the total mass of all the elements constituting the zinc oxide-based layer excluding oxygen and nitrogen.

[0122] The zinc oxide-based layers may comprise one or more elements selected from aluminum, titanium, niobium, zirconium, magnesium, copper, silver, gold, silicon, molybdenum, nickel, chromium, platinum, indium, tin and hafnium, preferably aluminum.

[0123] Zinc oxide-based layers can optionally be doped with at least one other element, such as aluminum.

[0124] The zinc oxide-based layer comprises, in order of increasing preference, at least 80%, at least 90%, at least 95%, at least 98%, at least 100%, by mass of oxygen relative to the total mass of oxygen and nitrogen.

[0125] Preferably, the dielectric coating located directly below the silver-based functional metal layer comprises at least one crystallized dielectric layer, in particular based on zinc oxide, optionally doped with at least one other element, such as aluminum.

[0126] These zinc oxide layers have a thickness:

[0127] - 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

[0128] - not more than 25 nm, not more than 10 nm, not more than 8.0 nm.

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

[0130] Preferably, the first dielectric coating comprises at least one dielectric layer based on: a nitride or an oxynitride of aluminum and / or silicon and / or zirconium or a mixed oxide of zinc and tin, or a titanium oxide.

[0131] Preferably, the first dielectric coating comprises:

[0132] - a layer based on a nitride or oxynitride of aluminum and / or silicon and / or zirconium, and / or

[0133] - a layer based on a mixed oxide of zinc and tin, and / or

[0134] - 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 located above, preferably in contact with, the layer based on a nitride or oxynitride of aluminum and / or silicon and / or zirconium.

[0135] The zinc tin oxide layer is located below, preferably in contact with, the zinc oxide layer.

[0136] These dielectric layers with barrier function have, in order of increasing preference, a thickness: less than or equal to 40 nm, less than or equal to 30 nm, less than or equal to 25 nm, and / or greater than or equal to 5 nm, greater than or equal to 10 nm or greater than or equal to 15 nm.

[0137] The substrate coated with the electrically conductive coating or the coating alone may not have undergone heat treatment. The present invention relates to the non-heat-treated material or the heat-treated material.

[0138] The electrically conductive coating may not have undergone heat treatment at a temperature above 500°C, preferably 300°C.

[0139] The coating may have undergone a heat treatment at a temperature above 300°C, preferably 500°C. In this case, the heat treatments are chosen from annealing, for example by a rapid thermal annealing ("Rapid Thermal Process") such as laser or flash lamp annealing, quenching and / or bending. Rapid thermal annealing is for example described in application WO2008 / 096089. The heat treatment temperature (at the coating) is above 300°C, preferably above 400°C, and better still above 500°C.

[0140] The substrate coated with the coating can be curved or tempered glass.

[0141] The transparent substrates according to the invention are preferably made of a rigid mineral material, such as glass, or organic polymer-based (or polymer).

[0142] The organic transparent substrates according to the invention may also be made of polymer, rigid or flexible. Examples of polymers suitable according to the invention include, in particular: polyethylene, polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN); polyacrylates such as polymethyl methacrylate (PMMA); polycarbonates; polyurethanes; polyamides; polyimides; fluorinated polymers such as fluoroesters such as ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene (ECTFE), fluorinated ethylene-propylene copolymers (FEP); photocrosslinkable and / or photopolymerizable resins, such as thiolene, polyurethane, urethane-acrylate, polyester-acrylate resins and polythiourethanes.

[0143] The substrate is preferably a sheet of glass or glass-ceramic.

[0144] The substrate is preferably transparent, colorless (in which case it is 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 can also be of the borosilicate or aluminoborosilicate type.

[0145] According to a preferred embodiment, the substrate is made of glass, in particular soda-lime-silica or polymeric organic material.

[0146] The substrate advantageously has at least one dimension greater than or equal to 1 m, or even 2 m and even 3 m.

[0147] The thickness of the substrate generally varies between 0.05 mm and 19 mm. When the substrate is mineral, its thickness is preferably between 0.7 and 9 mm, in particular between 2 and 8 mm, or even between 4 and 6 mm. The substrate can be flat or curved, or even flexible. When the substrate is organic, its thickness is preferably between 1 and 2 mm.

[0148] Examples

[0149] I. Electrically conductive coatings

[0150] Electrically conductive coatings were deposited by sputtering onto a transparent glass substrate. The glass substrates were 2.1 mm aluminosilicate glass substrates.

[0151] Functional layers (F) are silver-based metal layers.

[0152] Dielectric coatings include:

[0153] - layers based on silicon nitride,

[0154] - layers based on zinc and tin oxide,

[0155] - layers of zinc doped with aluminum,

[0156] - indium and tin layers.

[0157] The blocking layers are selected from titanium, titanium nitride, nickel and chromium, zinc layers.

[0158] The deposition conditions of the layers, which were deposited by sputtering (so-called “magnetron cathode sputtering”), are summarized in Table 1.

[0159] [Table 1]

[0160]

[0161] Table 2 lists the materials of each layer or coating that constitutes the coatings according to their position relative to the substrate carrying the stack (last line at the bottom of the table).

[0162] [Table 2]

[0163] Early dielectric coatings include a SiN / SnZnO / ZnO sequence to prevent diffusion of chemical species from the substrate and to reduce surface roughness and optimize silver quality.

[0164] The coatings have not undergone high temperature heat treatment.

[0165] II. Determination of electrochemical properties In order to determine the electrochemical properties of conductive coatings with respect to mobile species of the electrolyte such as Li / Li-»-, voltammetric cycles were carried out. For this, the current response resulting from a continuous variation of the potential of the electroconductive coating (used as a working electrode) on which the electrochemical reaction studied takes place is measured.

[0166] The figures represent voltammetric cycles performed using a three-electrode setup with a lithium metal counter electrode, a lithium metal reference electrode, and a working electrode comprising the various electrically conductive coatings. The electrolyte is composed of a LiCIO4 / PC solution. The voltammograms are performed in the potential window of 2 to 4 V versus Li / Li+ at a scan rate of 2 mV / s.

[0167] 1. Nature of dielectric layers of the upper dielectric coating

[0168] The electrically conductive coatings Rev. 1, Rev. 2 and Rev. 3 differ in the choice of the conductive oxide layer(s) constituting the upper dielectric coating.

[0169] The tested electrically conductive coatings in Figure 1 have not undergone heat treatment. In this graph, the degradation of the coating is observed with an oxidation peak and a reduction peak as well as the rise of the current above 3.4 V vs Li / Li+. However, this phenomenon is less marked in the case of the use of a conductive oxide layer based on aluminum-doped zinc oxide. This is reflected in particular by a less marked peak in the case of Rev.1 than in Rev.2 or Rev.3. Therefore, the electrically conductive coating of the invention preferably comprises at least one layer of aluminum-doped zinc oxide having a thickness greater than 40 nm or greater than 50 nm.

[0170] 2. Nature of the blocking layers

[0171] 1. Absence of heat treatment

[0172] Rev.4 and Rev.5 differ from Rev.3 in the nature of the blocking layer (respectively TiN and NiCr versus Ti). Figure 2 shows the voltammogram cycles of these 3 coatings in the absence of heat treatment.

[0173] Changing the Ti metal blocking layer to TiN or NiCr strongly impacts the electrochemical window of silver. The current rise above 3.4V vs LI / LI+ is much lower and oxidation or reduction peaks around 3.6-3.7V vs Li / Li+ are no longer observed. The electrode coating is compatible with EC devices operating in the 2-4V vs Li / Li+ range.

[0174] The NiCr and TiN layers act effectively as a shield against any degradation of the silver layer that may occur during the deposition of a subsequent layer (sputter deposition), high temperature annealing and / or subsequent electrochemical reaction. Rev.6, Rev.7 and Rev.1 differ in the nature of the blocking layer (NiCr, Zn and Ti respectively). Figure 3 shows the voltammogram cycles of these 3 coatings. No heat treatment was performed.

[0175] The presence of a zinc or titanium-based metal blocking layer near the silver layer does not show any positive effect. The presence of redox peaks indicates the degradation of the electrode.

[0176] Rev.6 according to the invention exhibits good electrochemical stability. Only a very small increase in current above 3.4 V and no redox peaks are observed.

[0177] The invention allows the use of the silver-based coating in a high-contrast electrochromic device operating in the 2-4V vs Li / Li+ range.

[0178] 2. After heat treatment

[0179] After heat treatment at 600°C for 8 minutes, oxidation-reduction peaks are observed for Rev.1, Rev.7 and Rev.6. Figure 4 shows the voltammogram cycles of these 3 coatings after heat treatment.

[0180] For rev.7, which includes a zinc metal blocking layer, this phenomenon is particularly significant. An increase in current above 3.4 V is observed, as well as redox peaks at 3.6 and 3.7 V. After heat treatment, the presence of a zinc metal layer alone does not improve the electrochemical stability of silver.

[0181] For Rev.6 including a NiCr-based blocking layer, the positive impact of this layer is lower in the case of heat treatment.

Claims

Claims 1. Material comprising a substrate coated with a first conductive coating comprising, starting from the substrate: - a first dielectric coating, - a silver-based metallic functional layer, - a blocking layer located above and immediately in contact with the silver-based functional metal layer, chosen from metal layers of one or more elements chosen from nickel and chromium such as Ni, Cr, NiCr, and metal nitride layers of one or more elements chosen from titanium, nickel, 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 the second dielectric coating of which is greater than 40 nm.

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

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

4. Material according to any one of the preceding claims, characterized in that the second dielectric coating comprises a layer of conductive oxide chosen from mixed tin and indium oxide, tin-doped indium oxide, doped zinc oxide, doped ruthenium oxide and fluorine-doped tin oxide.

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

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

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

8. Material according to the preceding claim, characterized in that the crystallized 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, characterized in that the first dielectric coating comprises: - a layer based on silicon nitride or oxynitride of aluminum and / or zirconium, and / or - a layer based on zinc and tin oxide.

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

11. Electrochromic system comprising: - a material comprising a substrate coated with a first conductive coating comprising, starting from the substrate: - a first dielectric coating, - a silver-based metallic functional layer, - a blocking layer located above and immediately in contact with the silver-based functional metal layer, chosen from metal layers of one or more elements chosen from nickel and chromium such as Ni, Cr, NiCr, and metal nitride layers of one or more elements chosen from titanium, nickel, 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 is greater than 40 nm, - a first active layer comprising an electrochromic material, - an electrolyte layer, - a second active layer and - a second transparent electroconductive coating, - possibly a substrate.

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