WO2017216428A1

WO2017216428A1 - All-solid-state electrochromic device, electronically auto-active layer for this device, and process for producing this device

Info

Publication number: WO2017216428A1
Application number: PCT/FR2016/051458
Authority: WO
Inventors: Corinne Marcel; Timothée VENOT
Original assignee: Commissariat A L'energie Atomique Et Aux Energies Alternatives
Priority date: 2016-06-16
Filing date: 2016-06-16
Publication date: 2017-12-21

Abstract

An in particular electrically controllable all-solid-state electrochromic device the infrared emissivity or reflectivity of which is controlled, comprising but preferably consisting of a stack, said stack comprising in succession from a back side (3) to a front side (1) that is exposed to the infrared rays (2): a substrate (4) made of an electronically conductive material, or a substrate made of an electronically non-conductive material covered with a layer made of an electronically conductive material, forming a first electrode; a layer made of a proton-storing first electrochromic material (5); a layer of an electronically insulating and protonically conductive electrolyte (6); an electronically conductive and electronically auto-active layer (7) the reflectivity of which in the infrared is variable, of a pre-protonated second electrochromic material with a variable degree of proton intercalation, said second material being chosen from pre-protonated crystallised tungsten oxide HxW03-c and pre-protonated crystallised hydrated tungsten oxide HxW03.nH20-c (7) where x is comprised between 0.2 and 1 and n is an integer from 1 to 2, the content in terms of unremovable protons of the second electrochromic material always being equal to 0.2; and optionally a protective layer (8) that is transparent to the infrared rays. A method for producing said electronically auto-active layer for this device. A process for producing this device.

Description

ALL-SOLID ELECTROCHROME DEVICE, ELECTRONICALLY SELF-ACTIVE LAYER FOR THIS DEVICE, AND METHOD FOR PREPARING

THESE MEASURES.

DESCRIPTION

TECHNICAL AREA

The invention relates to an all-solid electrochromic device.

More specifically, the invention relates to an electrochromic device all-solid reflection or infrared emission controlled, in particular electrically controllable type.

The invention further relates to an electronically active active layer, also referred to as an electronically-active layer having an electrode function for such an electrochromic device.

The invention finally relates to a method for preparing said device.

The technical field of the invention can be defined as that of electrochromic devices active in the infrared. STATE OF THE PRIOR ART

There are currently two families of electrochromic devices active in the infrared, namely flexible devices that can be "all-organic" exclusively based on organic polymers or hybrid, and "all-solid" devices consisting of stacks of inorganic or mineral layers.

If one is interested in "all-organic" devices, the document FR-A1-2 825 481 describes a flexible electrochromic structure operating in reflection at wavelengths between 0.35 and 20 μιη which comprises a membrane microporous polymer including a generally liquid electrolyte, and deposited on each of the surfaces of the microporous membrane and in this order: an electrode formed of an electronically reflective conductive layer, for example gold, a layer of electrochromic conductive polymer for example of polyaniline, polythiophene, or polypyrrole, and a flexible and transparent window.

The device described in this document has fragile interfaces that limit its life. Indeed, the electrolyte is generally liquid, and if a leakage occurs to occur, it can then occur an electrolyte leak possibly leading to drying of the device.

The lack of electrolyte seriously affects the electrochromic properties.

The document WO-A1-2010 / 058108 describes an electro-emissive device comprising a material in the form of a semi-interpenetrating network of polymers. This device has the advantage of not requiring a gold layer to function.

Although having a very good cyclability at room temperature combined with a simplified architecture, this device also requires a step of impregnation in a liquid electrolyte. In addition, the tests performed at high temperature reveal a degradation of the electrochromic properties, which therefore requires the use of at least one additional metal layer, as described in the document FR-A1-2 996 804.

This document describes a radiative surface comprising a first ionic conductive polymer and a second electronically and electrochromically conductive polymer constituting an interpenetrating network of polymers. The network, which is impregnated with an electrolyte, further comprises a metal layer on one side in contact with solar radiation to reduce the absorption of solar radiation. However, the electrochromic performances of the device of FR-A1-2 996 804 are reduced compared to those of the devices not comprising an additional metal layer. Hybrid devices are described in document FR-A1-2 879 764. This document relates to a flexible, aqueous, controlled emission electrochemical cell which comprises, inter alia, a porous active layer formed of a mixture of PVDF-HFP, of PEO and a powder of an insertion material, and a porous counter-electrode formed of a mixture of PVDF-HFP, PEO and a powder of a compound comprising ions complementary to the ions of insertion.

The insertion material WO3.H2O has a good proton conduction combined with a reflection I R adjustable on a carbon-absorbing background, ion permeable and current collector.

Although more robust than the document

FR-A1-2 825 481, this device, intimately laminated with a gelled electrolyte, also requires to be encapsulated by a sealed and transparent window in the infrared, which complicates its design.

Flexible devices, whatever they are, have in particular the disadvantage, particularly when used for the thermal protection of satellites, to be poorly adapted to the spatial conditions.

In fact, gel electrolytes pose problems when they are used under vacuum, and the polymers that constitute the flexible devices deform under the effect of heat and are not very resistant to UV.

The "all-solid", "controllable" devices are most often designed for application in the glazing field, and combine visual comfort and thermal comfort in the visible and near infrared (IR) range.

The active material generally consists of a porous tungsten oxide layer that is weakly crystallized, that is to say, amorphous with X-rays.

This so-called layer of H _x W03-a becomes absorbent when the material is interposed, in other words when protons are inserted therein, ie when x> 0. An example of such an "all-solid" device is described in the document FR-A1-2 904 704 which relates to an electrochemical device, and / or electrically controllable type glazing and optical properties and / or variable energy.

This device comprises an "all-solid" electrochromic stack of structure TC1 / EC1 / EL / EC2 / TC2 with a carrier substrate provided with a first electroconductive layer TC1, a first electrochemically active layer EC1 capable of reversibly inserting ions as cations such as H ⁺ or Li ⁺ or anions such as OH ^" , in particular a cathodic or anodic electrochromic material, an electrolyte layer EL, a second electrochemically active layer EC2 capable of reversibly inserting said ions , in particular in a cathodic or anodic electrochromic material, and a second electroconductive layer TC2.

Each electro-active layer EC1 or EC2 may in particular comprise tungsten oxide.

However, this all-solid device can not be used for a modulation of the average infrared radiation, namely a wavelength generally of 1.5 to 20 μιη, because the electrodes TC1 and TC2 are not transparent beyond of 2 μιη, due to their high conductivity.

Thus, particular problems arise for electrochromic devices "all-solid", inorganic, active in the infrared.

Indeed, electrochromic devices active in the infrared of conventional design require a transparent electrode in the infrared so that the signature of the active material can be effective and flexible.

Thus, US Pat. No. 7,265,890 discloses an electrochromic device which comprises, on a rigid or flexible substrate, an electrode constituted, for example, by a metal film or by a conductive metal oxide layer such as ΓΙΤΟ, an electrochromic layer. , for example in tungsten oxide charged with lithium ions, a lithium nitride ion transfer layer, an electrolyte layer, an ion storage layer, and a transparent metal electrode.

In this device, the active material Li _x WO 3 is deposited at the rear of the stack.

The performance of such a device is then limited by the infrared transparency of the upper layers constituted by the electrolyte, the counter-ion reservoir electrode and the electrode responsible for bringing the current there.

Stacks active in the infrared, and especially in the medium-infrared, namely a wavelength generally of 1.5 to 20 μιη, may comprise a layer of tungsten oxide H _x W03-a front face and absorbent on reflective background.

The document by K. Sauvet, L. Sauques and A. Rougier, Journal of Physics and Chemistry of Solids 71, (2010), 696-699, mentions the use of a reflective porous gold grid as an electrode for H _x W03-a like the architecture used in the flexible system "all-organic" FR-A1-2825481, where the optical signature of the active material is disconnected from the rest of the device.

However, in the case of complete systems designed by these authors, the use of an infrared-transparent electrode, in addition to the micron mesh gold grid, remains necessary in order to bring the electrons into the active material.

However, the transparent electrodes in the infrared are still in the research state, and are difficult to industrialize.

At present, transparent gold grids in the submillimetric mesh infrared are used by photolithography on transparent BaF ₂ glass, which drastically complicates the production of the devices. Thus, document FR-A1-2 934 062 relates to an electrochromic device with controlled infrared reflection, in particular of the electrically controllable type, which comprises, between a transparent carrier substrate in the IR domain and a counter-substrate, a stack comprising, successively:

a metal grid, preferably made of gold, transparent in the infrared range, forming a first electrode,

an electrochromic functional system comprising a layer of a first electrochromic ion storage material (EC1), preferably based on iridium oxide, at least one electrolytically functional layer (ELI, EL2) preferably based on oxide of tantalum and tungsten oxide, and a layer of a second electrochromic material (EC2),

a metallic layer capable of reflecting the infrared radiation, forming a second electrode,

a lamination interlayer of thermoplastic material.

Thus, in view of the foregoing, there existed a need for an electrochromic device, active in the infrared, preferably in the medium infrared, in particular with infrared (IR) modulatable emissivity which makes it possible to overcome the use of electrodes transparent to infrared radiation and in particular gold grids.

In view of the foregoing, there still exists a need for an electrochromic device, active in the infrared, preferably in the mid-infrared, robust, having a high mechanical resistance, resistant to high temperatures, for example higher or 100 ° C, resistant to ultraviolet radiation, can be placed in a vacuum environment, for example in space.

There was also a need for a device that could be manufactured by a simple process with a limited number of steps and a reduced duration. It is to meet, among others, the needs listed above that has been developed an electrochromic device, active in the infrared, preferably in the middle infrared, which was the subject of the French application FR -A1-2 969 323 and the corresponding international application WO-A1-2012 / 080312.

Although this device does indeed meet, among other things, the needs listed above, it nevertheless has the disadvantage of having an active part on the front face in the form of a bilayer, the realization of which is complex when it is integrated into the complete device.

The object of the present invention is to provide an electrochromic device, active in the infrared, preferably in the medium infrared, which while having all the advantageous properties of the device described in WO-A1-2012 / 080312, which are largely exposed in this document, does not have the disadvantages, limitations, defects and disadvantages of the device of this document, and which solves the problems of the device of this document related in particular to the bilayer that includes this device.

STATEMENT OF THE INVENTION

This and other objects are achieved, according to the present invention, by an all-solid electrochromic device with reflection or controlled infrared emission, in particular of the electrically controllable type, comprising, preferably consisting of, a stack, said stack comprising successively from a rear face to a front face exposed to infrared rays:

a) a substrate of an electronically conductive material, or a substrate of a non-conductive electronic material covered with a layer of an electronically conductive material, said substrate of a conductive material electronic or said layer of an electronically conductive material forming a first electrode;

b) a layer made of a first electrochromic protonic storage material;

c) a layer of a conductive electrically conductive and electrically insulating electrolyte;

d) an electron-selective self-active layer with variable reflection in the infrared (preferably in the infrared medium) and electronically conductive, of a second preprotonated electrochromic material with variable proton intercalation rate, chosen from preprotonated tungsten oxide and crystallized H _x W03-c, where x which represents the proton content of the material is between 0.2 and 1 (0.2 and 1 inclusive), and the preprotonated and crystallized tungsten oxide hydrated HxWOs.nl-hO where x, which represents the proton content of the material, is between 0.2 and 1 (0.2 and 1 inclusive), and n is an integer of 1 to 2, the content of irremovable, non-removable protons incorporated (intercalated) irreversibly, said second electrochromic material being always equal to 0.2;

e) optionally, a protective layer, transparent to infrared rays, of an inorganic material;

said stack not comprising a stoichiometric tungsten oxide layer WO 3 _y where y is between 0.2 and 1.

Advantageously, the all-solid electrochromic device with reflection or controlled infrared emission, in particular of the electrically controllable type, according to the invention, preferably comprises a stack, said stack consisting successively from a rear face to an exposed front face. infrared radiation in:

b) a layer made of a first electrochromic protonic storage material;

d) an electron-selective self-active layer with variable reflection in the infrared (preferably in the infrared medium) and electronically conductive, of a second preprotonated electrochromic material with variable proton intercalation rate, chosen from preprotonated tungsten oxide and crystallized H _x W03-c, where x which represents the proton content of the material is between 0.2 and 1 (0.2 and 1 inclusive), and the preprotonated and crystallized tungsten oxide hydrated HxWOs.nl-hO where x, which represents the proton content of the material, is between 0.2 and 1 (0.2 and 1 inclusive) and n is an integer of 1 to 2, the content of irremovable, non-removable protons incorporated irreversibly the second preprotonated electrochromic material always being equal to 0.2;

e) optionally, a protective layer, transparent to infrared rays, of an inorganic material.

The device according to the invention has never been described or suggested in the prior art.

The device according to the invention differs in particular from the device described in document WO-A1-2012 / 080312 in that the bilayer d) of the device of this document is replaced by a single specific layer with variable reflection in the infrared ( preferably in the infrared medium) and electronically conductive, of a second preprotonated specific electrochromic material with a variable protonic intercalation rate. This second specific electrochromic material is fundamentally characterized by the fact that its irremovably irremovably irremovable proton content is always equal to 0.2.

In addition, the second electrochromic material may be described as preprotonated or initially protonated material. That is to say, the crystalline tungsten oxide W03 _x H-c, and tungsten oxide crystallized hydrated H _x W03.nH20-c can be described as préprotoné tungsten oxide and crystallized H _x W03- c, and preprotonated and crystallized hydrated tungsten oxide

By preprotonated or previously protonated, it is meant that the second electrochromic material, at the end of the preparation of the layer d), after the deposition of the layer d), and before any exchange of protons, before any operation of the device, previously (hence the term "preprotonated") to any exchange of protons, prior to any operation of the device, has, contains, already protons, has a non-zero proton (x) rate.

In the second electrochromic material, these protons ("preprotonated") already contained, present in the layer before any exchange of protons, before any operation of the device, previously (hence the term "preprotonated") to any proton exchange, previously at any operation of the device are contained, present at a content, a proton level, which is already 0.2 (x = 0.2). It can be said that the preprotonation rate of the second electrochromic material is equal to 0.2.

It can also be said that the second material is initially protonated, in that, initially, at the initial moment, immediately before the proton exchange commences, immediately before the device begins to operate, it already contains protons. it already has a proton level, and this proton rate, called the initial proton rate, is 0.2 (x = 0.2).

These preprotonated protons, initially present in the second material, are furthermore, according to the invention, irremovable protons, no exchangeable, incorporated irreversibly in the second electrochromic material, at a content, an initial proton level of 0.2. As will be seen below, these protons are non-exchangeable, irremovable, irreversibly incorporated in the second electrochromic material, because the second electrochromic material is crystallized by heating simultaneously with the incorporation of the protons into the material, which renders their incorporation irreversible. .

In other words, the second electrochromic material comprises irremovable, non-exchangeable protons which can not be exchanged in a reversible manner and which are irreversibly incorporated into the material at a rate x = 0.2 at the end of the deposition of the layer and before any exchange of protons, before any operation of the device.

This rate, this irremovable, irremovable proton content of the second electrochromic material is always 0.2 before the operation of the device (hence the terms preprotonation, preprotonated), during which a proton exchange takes place.

The proton x rate of the second electrochromic material which is the total of the irremovable proton content (0.2) and the exchangeable mobile proton content of the second electrochromic material is, during operation, during which a proton exchange, always at least equal to 0.2.

In other words, in the second electrochromic material of the device according to the invention, all the protons are not exchangeable and some of these protons (x = 0.2) remain non-exchangeable, immovable, irreversibly, the other protons being well sure removable, exchangeable, reversibly.

This layer d) may be called more simply simply an electronically active active layer or an electronically active self-active layer having an electrode function.

It can therefore be considered that the device according to the invention is based on a simplification of the design of the device described in WO-Al-2012/080312. Indeed, the bilayer of the device described in the document WO-Al-2012/080312 is replaced by a single layer made of a specific material that can be described as preprotonated, with a preprotonated proton content of 0.2, and whose content of immutable, non-exchangeable protons incorporated irreversibly (before operation) in the material is 0.2.

This single layer of the device according to the invention is capable of presenting variable reflection properties in an electronically autonomous manner, without resorting, as in the device of document WO-A1-2012/080312, to a second non-electrochromic and electronically conductive second layer. called electrode.

With respect to the layer of a second electrochromic material with variable proton intercalation rate of the bilayer of the device of document WO-A1-2012/080312, the layer of a second electrochromic material with variable proton intercalation rate of the device according to the invention is distinguished by the fact that the material which constitutes it is a preprotonated material, and in that the content of irremovable, irremovable protons irreversibly incorporated in the second electrochromic material is always equal to 0.2.

Indeed, the second electrochromic material of the device according to the invention is preprotonated because it presents at the end of the preparation of the layer d), after the deposition of the layer d), and before any exchange of protons, before any operation of the device a content, a rate of protons, said initial proton rate, which is not zero, and which is already 0.2 (x = 0.2). And these "preprotonated" protons are made irremovable by heating crystallization, simultaneously with their incorporation in the layer d) (ie simultaneously with the preprotonation), and before any exchange, before any operation of the device.

On the other hand, the second electrochromic material with a variable proton intercalation rate of the bilayer of the device of document WO-A1-2012/080312 is not preprotonated because, at the end of the preparation of this layer, it presents result of the deposit of this layer, and above all proton exchange, before any operation of the device, a content, a proton level of zero (x = 0).

Then, the crystallized tungsten oxide H _x WO 3 -c or the hydrated crystallized tungsten oxide HxWOs.nl-hO-c which constitutes the layer d) of the device according to the invention has a non-exchangeable, irremovable proton content, irreversibly incorporated into the second electrochromic material which is always equal to 0.2, whereas in the layer of a second electrochromic material of the device of document WO-A1-2012 / 080312, x is between 0 and 1, and the content in irremovable protons, non-exchangeable irreversibly incorporated in the second electrochromic material of the device of WO-A1-2012 / 080312 is zero. That is to say that in the layer of a second electrochromic material of the device of WO-A1-2012 / 080312, all the protons are removable, exchangeable. In the device of document WO-A1-2012 / 080312, the proton level of the second electrochromic material may, during operation, be less than x = 0.2 and even be equal to 0, since all the protons are removable, whereas that in the device according to the invention, x can not be less than 0.2.

It can be said that the second electrochromic material of the device according to the invention is a preprotonated material -because at the end of its preparation and before any exchange of protons, any operation of the device, a rate, proton content greater than zero. , non-zero and equal to 0.2 (x = 0.2) - and crystallized (simultaneously with the preprotonation), this crystallization thus rendering this preprotonation at a content of 0.2 immovable, definitive and irreversible.

It will be understood that, before any operation, x = 0.2 and that during operation x may vary from 0.2 to 1.

In other words, in the layer of the second electrochromic material of the device of document WO-A1-2012 / 080312, the content of removable protons is always 0.2 greater than the content of removable protons in layer d). a second electrochromic material of the device according to the invention. It is in a surprising way, the implementation of such a second specific electrochromic material, preprotonated, with a content of non-exchangeable irremovable protons incorporated irreversibly in the second electrochromic material which is always equal to 0.2, which allows to replace the bilayer of WO-A1-2012 / 080312 by a single layer.

This preprotonation is, according to the invention, generally carried out in situ during the manufacture of the single layer, during its formation, for example by introducing water vapor into the PVD chamber, for example magnetron sputtering. This water vapor decomposes and reacts with WO3 for the "preprotoner", with a proton x content of 0.2.

During its deposition and thus its (pre) protonation, a heating of the preprotonated layer, for example at a temperature of 100 ° C. to 300 ° C., also makes it possible to crystallize the layer and render the protons thus incorporated during the ) protonation irremovable, non-releasable, non-releasable.

In other words, in the device of document WO-A1-2012 / 080312, the crystallized tungsten oxide H _× WO 3 -c, the hydrated crystallized tungsten oxide H _× W0 3 .nH 2 O -c, is not protonated initially, preprotonated, as in the device according to the invention; it is only crystallized to have a modulable reflectivity, and a heating of the substrate at a higher temperature, for example at a temperature Ts of 350 ° C, is then necessary.

Therefore, in the device of WO-A1-2012 / 080312, an electron conducting sublayer of WO 3- _y is required to activate crystallized tungsten oxide H _x WO 3 -c or hydrated crystallized tungsten oxide H _x W03.nH20-c, hence the presence of a bilayer d) in the device of WO-A1-2012 / 080312.

In addition, it should be noted that in WO-A1-2012 / 080312, the operation of this bilayer is demonstrated using an external aqueous electrolytic medium, while the actual operation of the device according to the invention has has been proven without the use of external aqueous electrolytics. Apart from the replacement of the bilayer by a single layer, the other layers of the device according to the invention are generally identical to those of the device of WO-A1-2012 / 080312.

It was not easy to replace the bilayer of the device of document WO-A1-2012 / 080312 by a single layer, whereas the person skilled in the art was not instigated at all and was instead diverted to it. Indeed, one could possibly expect a significant degradation of the properties of the device of WO-A1-2012 / 080312 by performing such a replacement, while it is not.

The device according to the invention, by virtue of the implementation of this single layer d) and not of a bilayer, does not therefore have the disadvantages of the device of document WO-A1-2012 / 080312 linked in particular to this bilayer, and provides a solution to the problems presented by the device of WO-A1-2012 / 080312.

Indeed, the replacement of the bilayer by a single layer greatly simplifies the device, and its manufacturing process is less complex, less time consuming and less expensive.

The device according to the invention generally retains all the advantageous properties of the device described in WO-A1-2012 / 080312. Finally we can say that the device according to the invention has all the advantageous properties of the device described in WO-A1-2012 / 080312 but without the disadvantages.

The variable reflection layer d) is more or less reflective depending on the value of x.

Thus for x = 0.2, this layer is not reflective and for x = 1, this layer is reflective.

Advantageously, said substrate when it is made of an electronically conductive material, can be made of a material chosen from the materials that are mechanically and chemically resistant to the stresses of the external environment. (For example in space) and chemically compatible with a protonic operation and in particular chemically compatible vis-à-vis the first electrochromic material proton storage, preferably said electronically conductive material is selected from metals such than aluminum, platinum or chromium, and their alloys.

By material "chemically compatible vis-à-vis a proton operation" generally means a material whose properties (chemical, physical, mechanical, electronic) are not degraded during operation of the device with protons.

By "chemically compatible vis-à-vis the first electrochromic material proton storage" is generally meant that the electronically conductive material reacts little or not with the first electrochromic material proton storage, or that the electronically conductive material is inert vis- with respect to the first electrochromic protonic storage material.

Generally, herein is generally meant that a first material is chemically compatible with a second material, when the first material reacts little or not with the second material, or the first material is inert with respect to the second material. the second material.

Advantageously, said substrate when it is made of an electronically non-conductive material may be made of a material chosen from mechanically and chemically resistant materials subjected to the stresses of the external medium (for example in space) and chemically compatible with respect to a proton and especially chemically compatible operation vis-à-vis the first electrochromic material proton storage, preferably said non-conductive electronic material is selected from glasses and mechanically and chemically resistant organic polymers, such as poly (ethylene terephthalate) ) or PET. Advantageously, the layer made of an electronically conductive material may be made of a material chosen from materials that are mechanically and chemically resistant to the stresses of the external medium (for example in space), and chemically compatible with proton and particularly chemically compatible vis-à-vis the first electrochromic material proton storage, preferably said electronically conductive material is selected from metals such as aluminum, platinum, chromium and their alloys; and electronically conductive metal oxides such as tin-doped indium oxide or ITO and fluorine-doped tin oxide or FTO.

Advantageously, the first electrochromic protonic storage material may be chosen from electrochromic proton storage materials which are chemically compatible with respect to a protonic operation, in particular chemically compatible with the protonic conductive and electronic insulating electrolyte, preferably the first electrochromic protonic storage material may be chosen from metal oxides and hydrated metal oxides, preferably amorphous, such as amorphous tungsten oxide H _x W03 and hydrated amorphous tungsten oxide

where x is between 0 and 1, and n is an integer of 1 to 2, and mixtures of two or more of said oxides.

Preferably, the first electrochromic proton storage material is chosen from amorphous preprotonated tungsten oxide H _X WO 3 where x is between 0.2 and 1 (0.2 and 1 inclusive), preferably between 0.2 and 0. , (0.2 and 0.5 inclusive), and the hydrated amorphous preprotonated tungsten oxide HxWOs.nl-hO where x is between 0.2 and 1 (0.2 and 1 inclusive), preferably between 0 and , 2 and 0.5 (0.2 and 0.5 inclusive), and n is an integer of 1 to 2, i.e., the first electrochromic material is preferably substantially identical to the second preprotonated electrochromic material variable proton intercalation rate, but in the non-crystallized state, amorphous (without heating the substrate). This allows advantageously using a single metal tungsten target for the two electrochromic materials of the device.

However, it is important to note that the first electrochromic proton storage material chosen from amorphous preprotonated tungsten oxide H _X W03 where x is between 0.2 and 1 (0.2 and 1 inclusive), and the oxide of hydrated preprotonated tungsten HxWOs.nl-hO where x is between 0.2 and 1 (0.2 and 1 inclusive), and n is an integer of 1 to 2, is certainly a preprotonated material, because at the end of the preparation of the layer b), after the deposition of the layer b), and before any exchange of protons, before any operation of the device a content, a proton rate, called proton rate initial, or preprotonation rate, not zero; but unlike the second electrochromic material in which the preprotonation rate is equal to 0.2, in the first electrochromic proton storage material, this preprotonation rate is at least 0.2, which means that it can be greater than 0.2.

In addition, in the first electrochromic proton storage material, these "preprotonated" protons are not then rendered irremovable by crystallization before any exchange, before any operation of the device.

Indeed, this first electrochromic proton storage material is chosen from amorphous tungsten oxide H _X WO 3 and hydrated amorphous tungsten oxide HxWOs.nl-hO and these amorphous materials have not undergone, during the deposition of layer and preprotonation, heating crystallization treatment to make these at least 0.2 protons "preprotonated" immovable, non-exchangeable. The initial proton level of these amorphous tungsten oxides is therefore at least 0.2, but these are mobile, exchangeable, releasable protons.

The preprotonated amorphous tungsten oxide H _X W03 and the prepregnated amorphous tungsten oxide hydrated HxWOs.nl-hO of the first electrochromic proton storage material thus comprise only protons releasable, removable, exchangeable for the entire range of x from 0.2 to 1, because these materials are amorphous since they have not been heated leading to crystallization (as the layer g)), therefore they are certainly preprotonated, because they contain at the end of the preparation of the layer and before any exchange of protons, already protons, at an initial content defined by x = 0.2 at least, but these protons, contrary to the protons initially present in the layer g) crystallized by heating and non-amorphous, are protons, removable, releasable during operation.

Advantageously, the protonic conductive and electrically insulating electrolyte may be chosen from electrically conductive and electronically insulating electrolytes that are chemically compatible with a proton function, in particular chemically compatible (inert) with respect to the crystallized tungsten H _x W03-c (protonated tungsten oxide) or hydrated tungsten oxide crystallized W03.nH _x H ₂ 0-c, preferably the proton conductor and electronic insulator electrolyte can be selected from hydrated metal oxides , preferably amorphous, such as amorphous hydrated tantalum Ta ₂ Os oxide, amorphous hydrated zirconium oxide and mixtures of two or more of said oxides.

The electrolyte is hydrated and amorphous so that it can easily transport protons from the storage material to the active material in infrared reflection. The metal oxide of the electrolyte should generally be different from tungsten oxide.

It is very important to note that the use of amorphous hydrated ZrO ₂ zirconium oxide in the protonic conductive and electronically insulating electrolyte of an all-solid electrochromic device has never been described or suggested in the art. prior.

The amorphous hydrated ZrO ₂ zirconium oxide is not reactive with crystallized tungsten oxide H _x WO 3 -c (protonated tungsten oxide) or crystallized hydrated tungsten oxide H _x WO 3. nH ₂ 0-c. Surprisingly when the electrolyte comprises, preferably consists of amorphous hydrated ZrO ₂ zirconium oxide the operation of the device is optimized and is more reliable than when the electrolyte comprises, preferably is constituted by, the tantalum oxide Ta ₂ Amorphous hydrated bone.

Advantageously, the protective layer, which may be transparent to infrared rays, may be of a material chosen from materials that are compatible with proton operation, in particular chemically compatible with crystallized tungsten oxide H _x W03-c or hydrated crystallized tungsten oxide H _x W03.nH ₂ 0 -c, preferably the optional infrared-transparent protective layer may be of a material selected from non-toxic inorganic materials, preferably from predominantly dense metal and metalloid oxides, such as cerium oxide CeO ₂ , yttrium oxide Y ₂ O 3, silica SiO ₂ and mixtures of two or more of said metal or metalloid oxides .

By dense metal or metalloid oxides, it is generally meant that these oxides have a density greater than 99% of the theoretical density.

Advantageously, the substrate (electronic conductor or not) has a thickness of 0.175 mm to 1 mm.

Advantageously, the layer of an electronically conductive material which covers the substrate when the latter is a substrate made of an electronically non-conductive material, has a thickness of 50 to 150 nm.

Advantageously, the layer made of a first electrochromic proton storage material has a thickness of 0.5 to 3 μιη, preferably 0.6 to 1.4 μιη.

Advantageously, the layer made of a protonic conductive electrolyte and electronic insulator has a thickness of 0.2 to 1.2 μιη, preferably 0.4 to 1 μιη. Advantageously, the layer made of a second electrochromic material has a thickness of 0.5 to 3 μιη, preferably 0.6 to 1.4 μιη.

Advantageously, the protective layer transparent to infrared rays has a thickness of 0.01 to 0.1 μιη, preferably 0.02 to 0.05 μιη.

The device according to the invention comprises a specific stack of specific layers in a specific order which has never been described in the prior art relating to "all-solid" electrochromic devices.

In particular, as already indicated above, the device according to the invention comprises, instead of the bilayer of the device of WO-A1-2012 / 080312, a single layer of a single crystallized preprotonated specific electrochromic material capable of to modulate its infrared reflection autonomously electronically, thanks to a minimal protonation rate conferring electronic conduction properties and thus an electrode function.

This bi-functionality of the active material can certainly be found in the documents relating to "all-organic" devices described in the prior art, but never in those relating to "all-solid" electrochromic devices mentioned above.

The device according to the invention can be defined as an all-solid electrochromic device with reflection or emissivity that can be modulated in the infrared (IR), in particular in the medium infrared (wavelengths from 1.5 to 20 μιη), and in particular in band II (wavelength 3 to 5 μιη) and / or in band I II (wavelength 8 to 12 μιη) of the infrared spectrum, the active part of which is an electronically autonomous electrochromic layer, at tungsten oxide base which according to the invention is located on the front face of the device.

The range of wavelengths of preferred interest for the device according to the invention is indeed in the middle infrared ("M IR") that is to say in a wavelength range of 1, 5 to 20 μιη, in particular from 2 to 20 μιη, which is a preferred range for space applications whereas for Glazing type applications, the ranges of wavelength of interest are in the Visible - Near Infrared.

The fact of arranging the active part of the electrochromic device with variable proton intercalation rate, namely the electronically active autonomous layer d), on the front face of the device, that is to say on the side of the device which is directly exposed to Infrared rays are at the origin of many of the advantages of the device according to the invention.

Indeed, this electronically active layer d), this electrode d), exposed directly to the IR radiation, is capable, by reversible electrochemical insertion of protons (which have been preferred to lithium ions for kinetic reasons), to modulate the total infrared emissivity of the system as demonstrated in the examples provided below.

The electronically active layer of the second electrochromic material, preprotonated and variable protonic intercalation rate d), constitutes the first layer of the front face of the device. No obstacle, such as an additional electrode, therefore opposes its exposure to infrared rays, and no optical loss is created.

In the device according to the invention, as in the device of document WO-A1-2012 / 080312, one of the major drawbacks of the "all-solid" devices of the prior art in which the active layer is arranged is overcome. under an electrode, which must be necessarily transparent to infrared radiation with all the implementation difficulties that implies.

In particular, the device according to the invention does not include a gold grid, which greatly simplifies the manufacture of the device according to the invention and greatly lowers the cost.

More specifically, according to the invention, there is provided an all-solid, non-organic device which does not comprise an infrared radiation-transparent electrode such as a gold grid. In other words, the optical performance of the device according to the invention is produced by the intrinsic electronic properties of the electrochromic active material d) located on the front face of the stack.

This allows the optimal optical response of the system, regardless of the layers behind the front panel.

It can be said that the device according to the invention is made according to an optimized, simplified design, which further improves the already optimized design, of the device of document WO-A1-2012 / 080312 due to the replacement of the bilayer of the device of this document. WO-A1-2012 / 080312 by a single layer.

The device according to the invention is, furthermore, characterized in that it comprises an electrochromic, reflective, active layer consisting of crystallized or crystallized and hydrated preprotonated tungsten oxide of formula H _x W03-c or H W03.nH20 _x-c where x, which represents the proton content of the material is between 0.2 and 1 (0.2 and 1 inclusive), and n is an integer from 1 to 2, the content of protons irremovable, non-exchangeable irreversibly incorporated of this pretonated tungsten oxide constituting the second electrochromic material always being equal to 0.2.

This layer has a variable proton intercalation rate (defined by x) as a function of the applied voltage (terminals generally between +3 and - 3 volts).

This active layer, electrochromic d) is electronically conductive according to the invention with a minimum value of x equal to 0.2.

This layer d) itself produces a variable optical contrast in the infrared, preferably in the middle infrared (2 to 50 μιη).

The electrochromic material H _x W03-c where x is between 0.2 and 1 (0.2 and 1 inclusive), or H _x W03.nH20-c where x is between 0.2 and 1 (0.2 and 1 inclusive) and n is an integer from 1 to 2, is necessarily in the crystallized state so that an increase in the ion intercalation rate x (here it is usually protons H ⁺ ) from the initial value x = 0.2, produces in the layer d) an increase in the infrared reflection R.

In other words, the layer of electrochromic material H _x W03-c where x is between 0.2 and 1, or HxWOs.nl-hO-c where x is between 0.2 and 1 and n is a number. 1 to 2, disposed on the front face becomes reflective when interposed, thereby increasing the emissivity modulation of the device.

The "all-solid" device according to the invention is compatible with all the requirements that govern a use in space, in fact the entirely inorganic materials that constitute it allow it to withstand UV aggressions, vacuum and high temperatures, for example close to 100 ° C, unlike existing flexible devices whose electrolytes gels poorly support evacuation and whose polymers deform under the effect of heat and are resistant to UV.

The device according to the invention can be described as a robust, durable electrochromic device of simplified design.

The device according to the invention has, moreover, the advantage of being able to be realized very simply, in a limited number of steps, by a single method of deposition for all the layers.

The device according to the invention can therefore be realized in a reduced duration and with reduced costs.

Thus, the device according to the invention can be made entirely under vacuum using the same physical vapor deposition ("PVD" or "Physical Vapor Deposition") technology chosen for example from sputtering, laser ablation, or evaporation.

The invention furthermore relates to a preprotonated electrochromic material layer with a variable proton intercalation rate chosen from among the preprotonated and crystallized tungsten oxide H _x W03-c where x, which represents the proton content of the material, is included between 0.2 and 1, and the preprotonated and crystallized hydrated tungsten oxide HxWOs.nl-hO-c where x, which represents the content of protons of the material, is between 0.2 and 1, and n is an integer of 1 to 2, the irremovable, non-removable proton content incorporated irreversibly of said preprotonated electrochromic material with variable proton intercalation rate being always equal to 0.2.

This layer (d layer) has already been described in detail above.

In the preprotonated non-crystallized amorphous state (without heating of the substrate), and therefore without irremovable protons present with a content defined by x = 0.2 at least, this material, as already mentioned above, can also serve proton storage layer b), which makes it possible to use a single metal tungsten target for the two electrochromic materials of the device.

The advantages related to the specific composition of this layer d) have for the most part already been explained above in the context of the description of the device.

The invention also relates to a process for the preparation of said layer of preprotonated electrochromic material with variable proton intercalation rate, selected from preprotonated and crystallized tungsten oxide H _x WO-c where x, which represents the proton content of the material, is between 0.2 and 1, and the hydrated preprotonated and crystallized tungsten oxide HxWOs.nl-hO-c where x, which represents the proton content of the material, is between 0.2 and 1, and n is an integer of 1 to 2, the irremovably irremovably irremovable proton content incorporated irreversibly of said preprotonated electrochromic material having a variable protonic intercalation rate always being equal to 0.2, in which the following successive steps are carried out:

depositing on a substrate, or on a previously deposited layer, a layer of preprotonated electrochromic material selected from preprotonated tungsten oxide H _x W03-c, where x is 0.2, and preprotonated tungsten oxide hydrated HxWOs where n is 0.2 and n is an integer of 1 to 2 by a physical vapor deposition method or PVD using a target metal tungsten and a deposition atmosphere containing water vapor, the conditions of the PVD process being such that the water vapor decomposes into oxygen atoms and reactive protons to oxidize and protonate the tungsten;

at the same time as depositing, said layer of preprotonated electrochromic material is heated to a temperature such that the preprotonated tungsten oxide H _x W03-c where x is 0.2, and the hydrated preprotonated tungsten oxide H _x W03.nH20 where x is 0.2, and n is an integer of 1 to 2, crystallize, and the protons contained at a content x of 0.2, become irremovable, non-exchangeable.

Among the conditions of the PVD process that allow water vapor to be broken down into oxygen atoms and reactive protons to oxidize and protonate tungsten, there may be mentioned that of a power applied to the target proportional to the partial pressure water vapor.

Advantageously, said layer of preprotonated electrochromic material can be heated at a temperature of 100 ° C. to 300 ° C., preferably at a temperature of 150 ° C. to 250 ° C.

The method of physical vapor deposition or PVD may be chosen from sputtering, laser ablation and evaporation.

In other words, the intercalation of 0.2 protons in the layer (i.e., preprotonation) is achieved by specific PVD deposition conditions which have never been described or suggested in the prior art.

The heating then causes the crystallization of the layer, thus making this intercalation of 0.2 protons irreversible, and makes these 0.2 protons irremovable.

Suitable PVD deposition conditions are discussed below in the "detailed discussion of particular embodiments" section of this specification. By way of example, these PVD deposition conditions may be as follows: for a tungsten target of 150 mm in diameter, the application of a power of 100W combined with an 8% partial pressure of water vapor introduced in situ in the deposition chamber with 80 sccm of plasma gas consisting of argon (Total pressure = 2.55 10 ^-2 mbar, deposition time = 27 minutes).

The principle of the preparation is based on the decomposition of the water vapor into oxygen atoms and reactive protons during tungsten deposition, for example in pulsed DC mode (50 kHz, 2 μ)) (but the deposition can also be in RF mode), with heating of the substrate, at a temperature between 100 ° C and 300 ° C, preferably between 150 ° C and 200 ° C, for setting 0.2 protons to generate a minimum electronic conductivity 3 S / cm, necessary for the operation of the device.

Without intentional heating of the substrate, these conditions also make it possible to introduce protons into layer b) into a first protonic storage material. This layer b) is generally a layer which is also preprotonated, which is removable, but which is not crystallized, the "preprotonated" protons thus introduced into the layer, at a content at least equal to x = 0.2 (rate preprotonation = 0.2 at least) are not irremovable but releasable, exchangeable.

This level of protons releasable in the device, at least 0.2 in number, allows the reversible exchange of protons in the active layer from 0.2 to 1 at the maximum.

The invention also relates to a method for preparing the device according to the invention, as described above, in which the following successive steps are carried out:

a) depositing a layer of a first electrochromic proton storage material on a substrate of an electronically conductive material, or a layer of an electronically conductive material disposed on a substrate a non-conductive electronic material, said substrate made of an electronically conductive material or said layer of an electronically conductive material forming a first electrode;

b) depositing a layer of a proton conductive and electrically insulating electrolyte on the layer of a first electrochromic proton storage material;

c) preparing, on the layer deposited in step b), an electronically active self-active layer with variable reflection in the infrared and electronically conductive of a second preprotonated electrochromic material with variable proton intercalation rate, chosen from the preprotonated and crystallized tungsten oxide H _x W03-c where x, which represents the proton content of the material, is between 0.2 and 1 (0.2 and 1 inclusive) and the preprotonated and crystallized tungsten oxide hydrated HxWOs.nl-hO-c where x which represents the proton content of the material is between 0.2 and 1 (0.2 and 1 inclusive) and n is an integer of 1 to 2, the content of irremovable protons , irreversible, irreversibly incorporated from the second preprotonated electrochromic material always being equal to 0.2;

d) optionally, a protective layer, infrared-ray-transparent, of an inorganic material is deposited on the infrared-reflective layer of a second preprotonated electrochromic material.

Step c) of preparing a self-active electronic layer with variable reflection in the infrared and electronically conductive of a second preprotonated electrochromic material with variable protonic intercalation rate can be carried out as described above.

The process according to the invention is reliable and much simpler than the processes of the prior art. The method according to the invention as already mentioned above, in the context of the description of the device is notably simpler, less time consuming and less expensive than the method of document WO-A1-2012 / 080312, since in fact the replacement of the bilayer by a single layer, it includes one step less.

Advantageously, the layers are deposited by a physical vapor deposition method or PVD, chosen from sputtering, laser ablation and evaporation.

Advantageously, all the layers are deposited under vacuum by the same physical vapor deposition method, preferably by reactive magnetron sputtering.

For technical and economic reasons, magnetron cathode sputtering in reactive mode will be preferred because it ensures in particular a good control of the oxygen or water level in the plasma, high deposition rates, for example of about 30 nm / min for the material

good optical quality of the active material.

In addition, it makes it possible to prepare the crystallized material H _x W03-c or H _x W03.nH20-c on the front face without heating up the remainder of the stack.

Advantageously, all the steps are performed in the same vacuum chamber, without opening the chamber between each of the steps, which causes significant simplification of the process, a significant time saving without loss of protons, and reduced costs.

The invention further relates to the use of the device as described above for the thermal protection of an object.

This object can be in particular a vehicle and in particular a space vehicle such as a satellite.

The use of the device according to the invention is particularly advantageous in the case of vehicles such as satellites subjected to constraints, limitations on their onboard weight. Indeed, the device according to the invention is of a low mass and allows a significant weight saving compared to devices, for example mechanical devices, commonly used for thermal protection, especially in satellites.

Other advantages of the invention will appear better on reading the detailed description which follows in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic view of the device according to the invention. FIG. 2 is a graph which shows the variation of the modulation of the infrared reflection (reflectivity) in the II and III bands as a function of the deposition temperature for an electrochromic material HxW03.nH20-c where x is between 0.2 and 1 (0.2 and 1 inclusive), and n is an integer of 1 to 2, of a thickness of 600 nm, activated in H3 0 ₄ - 0.1 M protonated liquid medium deposited on an electronic insulating glass substrate .

The ordinate is plotted the variation of the infrared reflection (reflectivity) averaged AR (in%) in the bands II (curve A, points ■) and III (curve B, points ♦) and on the abscissa is carried the heating temperature of the material active crystallized during its deposition magnetron sputtering.

FIG. 3 is a graph which shows the variation of the resistivity p as a function of the deposition temperature for a preprotonated and crystallized electrochromic material HxWOs.nh Oc with x equal to 0.2 irremovable protons, and n is an integer of 1 at 2, with a thickness of 600 nm deposited on an electronic glass insulating substrate.

On the ordinate is carried the resistivity p (in Q.cm), and on the abscissa is carried the heating temperature of the crystallized active material during its deposition by magnetron sputtering.

FIG. 4 is a graph which illustrates the electrochemical control between +3 V (x = 0.2) and -3 V (x = 0.5) of a device according to the invention comprising, on the front face, a layer of material active HxWOs.nhhO-c heated to 150 ° C where x is between 0.2 and 1 (0.2 and 1 inclusive), and n is an integer of 1 to 2, of thickness 0.6 μιη whose intrinsic properties are shown in Figures 2 and 3; an electrolyte layer ZrC 2 .nhhO with a thickness Ιμιη; and a HxWOs.nhhO proton reservoir layer with a thickness of 0.6 μιη; on an ITO layer and a glass substrate. All the layers of the device were deposited by magnetron sputtering.

The ordinate is plotted the reflection coefficient R in the infrared range and the abscissa is the wavelength λ (in μιη) of the infrared radiation.

Curves A (solid line), B (dashed lines) correspond respectively to the absorbing and reflective states at values of x of 0.2 and 0.5 respectively.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

FIG. 1 represents a device according to the invention with proton operation comprising the electronically specific self-active layer according to the invention.

This device comprises a front face (1) exposed to infrared radiation (2) and a rear face (3) which is not exposed directly to infrared rays.

The device according to the invention firstly comprises a substrate or support (4), which essentially plays a role of metal support of the device.

The substrate or support (4) does not generally have infrared light transparency.

The substrate or support is generally of a light material.

This substrate or support (4) can be made of a material chosen from metals, glasses such as microscope slide glass, and organic polymers which have sufficient rigidity, such as Poly (ethylene terephthalate) or PET. . The metals which may constitute the substrate or support (4) may be chosen for example from aluminum, platinum, chromium and their alloys.

In the case where the substrate or support (4) is made of a material that is not electronically conductive, such as glass or PET, then a layer made of an electronically conductive material is deposited on the substrate or, more exactly, on the upper surface. of it.

This layer of an electronically conductive material acts as an electrode connected to the power supply of the device.

This electronically conductive material is generally selected from metals, and electronically conductive metal oxides.

The metals that can form the layer of an electronically conductive material may be chosen from the metals already mentioned above which may constitute the substrate or support.

Electronically conductive metal oxides are well known to those skilled in the art.

Examples of such conductive oxides are tin-doped indium oxide ("Indium Tin Oxide" or ITO), fluorine-doped tin oxide Sn0 ₂ ("fluorine tin oxide" or FTO in English).

The electronically conductive material of said layer, particularly when it is an electronically conductive metal oxide, is generally chosen from materials that can be deposited in a thin layer by a PVD process, such as sputtering or laser ablation. or evaporation, and preferably from the materials that can be deposited in a thin layer by sputtering.

In the case where the substrate or support is of a material that is electronically conductive such as a metal, then it is not necessary that a layer of an electronically conductive material is deposited on the substrate. The support or substrate (4), which can then be described as "monoblock" substrate, plays in this case both the role of mechanical support of the device already indicated above and the role of electrode connected to the power supply. of the device.

In Figure 1, it is this embodiment, without a layer of an electronically conductive material on the substrate, which is shown.

It is important that the material which constitutes the layer of an electronically conductive material when it is present, or the electronic conductive material which constitutes the substrate when said layer is not present, is chemically compatible with the material of the layer. a first electrochromic proton storage material (5) deposited on the substrate or on the layer of an electronically conductive material.

The material that constitutes the layer made of an electronically conductive material, or the electronically conductive material that constitutes the substrate so that it is chemically compatible with a proton medium, such as a hydrated metal oxide, will thus be chosen.

The substrate (4) generally has a thickness of 0.175 to 1 mm.

The substrate (4) is generally in the form of a sheet of light material.

Thus, the thickness of the substrate (4) is generally about 1 mm in the case of a glass substrate and about 175 μιη in the case of a polymer substrate, for example a PET substrate. .

The layer of an optional electronic conductive material generally has a thickness of 50 to 150 nm.

On the substrate or the layer of an electronically conductive material is disposed a layer of a first electrochromic material proton storage (5). This layer can also be called counter-electrode proton reservoir. The first electrochromic proton storage material may be selected from electrochromic metal oxides and hydrated metal oxides, and mixtures of two or more such oxides.

Preferably, these oxides are amorphous.

Examples of such oxides are hydrated tungsten oxide

where x is between 0 and 1 (0 and 1 inclusive), and n is an integer of 1 to 2, for example n = 1.

Preferably, the first electrochromic proton storage material is chosen from preprotonated amorphous tungsten oxide H _X WO 3 where x is between 0.2 and 0.5 (0.2 and 0.5 inclusive), and the oxide of preprotonated amorphous tungsten hydrated HxWOs.nl-hO where x is between 0.2 and 0.5 (0.2 and 0.5 inclusive) and n is an integer of 1 to 2.

The first electrochromic material is preferably substantially identical to the second preprotonated electrochromic material with variable proton intercalation rate but in the uncrystallized, amorphous state (without heating the substrate). This advantageously makes it possible to use a single metal tungsten target for the two electrochromic materials of the device.

The choice of the latter oxide similar to that of the active layer d), therefore has the advantage of further simplifying the method of preparation of the device according to the invention by reducing the number of targets, precursors implemented.

The first electrochromic proton storage material is generally chosen from the materials that can be deposited in a thin layer by a PVD process such as cathodic sputtering, laser ablation or evaporation, and preferably from the materials that can be deposited under thin layer by sputtering.

The first electrochromic proton storage material will be chosen so that it is chemically compatible with the proton conductive electrolyte deposited on the layer of first electrochromic material. The layer made of a first electrochromic proton storage material (5) generally has a thickness of 0.5 to 3 μιη, preferably 0.6 to 1.4 μιη.

On the layer made of a first electrochromic proton storage material (5) is arranged a layer of an electrically conductive and electronic insulating electrolyte (6).

This proton conducting electrolyte may be chosen from all of the hydrated metal oxides, preferably amorphous, and mixtures of two or more of these oxides.

Indeed, the amorphous oxides lead the protons much better.

Examples of such oxides are amorphous hydrated Ta ₂ Os tantalum oxide and amorphous hydrated zirconium oxide.

As already mentioned above, the use of amorphous hydrated ZrO ₂ zirconium oxide in the protonic conductive and electronically insulating electrolyte of an all-solid electrochromic device has never been described or suggested in the literature. prior art.

The amorphous hydrated ZrO ₂ zirconium oxide is not reactive with crystallized tungsten oxide H _x WO 3 -c (protonated tungsten oxide) or crystallized hydrated tungsten oxide H _x WO 3. nH ₂ 0-c.

Surprisingly when the electrolyte comprises, preferably consists of amorphous hydrated ZrO ₂ zirconium oxide the operation of the device is optimized and is more reliable than when the electrolyte comprises, preferably is constituted by, the tantalum oxide Ta ₂ Amorphous hydrated bone.

The layer made of a protonic conductive electrolyte and an electronic insulator (6) generally has a thickness of 0.2 to 1 μιη, preferably 0.4 to 1 μιη.

On the layer of a proton conductive electrolyte (6) is disposed a layer (7) of a second electrochromic material selected from preprotonated crystallized tungsten H _x W03-c where x is between 0.2 and 1 (0.2 and 1 inclusive) and preprotonated hydrated crystallized tungsten oxide HxWOs.nl-hO-c where x is between 0.2 and 1 and n is between 1 and 2 the irremovably incorporated non-exchangeable proton content, irreversibly incorporated, of said second electrochromic material always being 0.2

This layer made of a second electrochromic material (7) is generally a porous layer with submicron porosity, for example from 10 to 100 nm.

This layer of a second electrochromic material (7) is a reflective layer with respect to IR rays and electronically conductive.

In this layer, the active material is a crystallized tungsten oxide represented by the formula H _x WO 3 -c, which can be hydrated to improve its performance, and essentially proton conductivity.

This hydrated crystallized tungsten oxide is represented by the formula

In these formulas, x which represents the intercalation ratio of the active material H _x WO 3 -c or H _x WO. N l-hO-c is variable and is between 0.2 and 1 (0.2 and 1 inclusive), while n is generally between 1 and 2 (1 and 2 inclusive). The material is thus preprotonated, with irremovable protons (0.2), with sufficient electronic conduction to activate.

The optical response of the device follows the variations of x, with possible modulation to within 0.1, because of the ability of inorganic layers to maintain their proton levels, also called "memory effect".

In other words, the optical properties, the optical response, of the preprotonated, electrochromic, electronically conductive, crystallized and / or hydrated tungsten active oxide layer of formula H _x W03-c or HxWOs.nl-hO-c (7) where x is between 0.2 and 1 (0.2 and 1 inclusive), and n is an integer of 1 to 2, can be easily modulated depending on the proton intercalation rate (defined by x) which is itself variable depending on the applied voltage. Thus by modifying this voltage, it will be possible to act on the optical properties of the device. For example, for an applied voltage of +3 V, x = 0.2, and for an applied voltage of -3 V, x = 0.5.

It should be noted that WO3 tungsten oxide, which constitutes the active part of the stack of the device according to the invention is a material capable of operating with lithium ions and / or with protons.

According to the invention, it is chosen to operate WO3 tungsten oxide with protons rather than with Li ⁺ ions, for reasons related to the kinetics and technological choice of pre-protonation in situ.

Indeed, the "all-solid" devices such as the device according to the invention being slower than the flexible devices, it is preferable to work with a second electrochromic proton material, with an inorganic electrolyte proton for example oxide type zirconium Zr0 ₂ , optionally hydrated, and finally with an inorganic counter-electrode also proton.

Indeed, zirconium oxide has the advantage of not reacting with tungsten oxide as well crystallized as amorphous and avoids any short circuit.

The second electrochromic active material layer (7) generally has a thickness of 0.5 to 3 μιη, preferably 0.6 to 1.4 μιη.

The optical properties of the device are adaptable in the mid-infrared with the thickness and the resistivity related to the deposition temperature of active material H _x W03-c, or H _x W03.nH20-c where x is between 0.2 and 1 (0.2 and 1 inclusive), and n is an integer of 1 to 2, in particular on the bands II (3-5 μιη) and I II (8-12 μιη) of transparency of the atmosphere.

For example, a heating temperature of 150 ° C. with a thickness of 0.6 μιη of active material will give the best modulation on the two bands.

In summary, the optical properties, the optical contrast, of the device according to the invention can be modulated in the infrared and in particular in the mean infrared by varying x and the thickness of the active material H _x W03-c or H _x W03.nH20-c where x is between 0.2 and 1 (0.2 and 1 inclusive), and n is an integer of 1 to 2.

Optionally, on the layer of second electrochromic active material (7) is disposed a layer (8) for protecting the stack, transparent to infrared rays, and preferably reflective vis-à-vis solar radiation.

This layer (8) can also be called the encapsulation layer. Indeed, this layer (8) can be deposited during a final step on the entire stack described above to maintain the ion content (protons) inside the device, and thus serve as encapsulation material.

By transparent to infrared radiation, it is generally understood that this layer (8) is transparent to infrared rays of wavelengths between 2.5 μιη and 25 μιη, preferably between 3 μιη and 12 μιη.

This layer (8) is generally made of a non-toxic inorganic material.

Preferably, this layer (8) is made of a material chosen from oxides of metals and metalloids, and mixtures of two or more of these metal oxides and metalloid oxides.

This or these oxide (s) of metals or metalloids, preferably amorphous, are preferably chosen from oxides which can be easily deposited by PVD from an oxide or metal target, such as cerium CeO ₂ , yttrium oxide Y2O3, or S102.

The layer (8) for protecting the stack generally has a thickness of 0.01 to 0.1 μιη, preferably 0.02 to 0.05 μιη, more preferably 0.05 μιη.

It should be noted that the encapsulation layer (8) is not mandatory, and is only optional. It will be present in particular for purposes of prolonged storage and use under vacuum of the device. The device shown in Figure 1 includes such a layer, but this is only an example.

The device according to the invention further comprises means (9, 10) for establishing a variable voltage between the electrodes, for example a variable voltage between +3 volts and -3 volts.

The device according to the invention is prepared by the method described above.

The apparatus used to implement the method according to the invention for preparing the device according to the invention may for example be a vacuum deposition frame ("Physical Vapor Deposition" or "PVD" in English) comprising:

a vacuum chamber of a volume for example of 0.1 m ³ in which there is an initial pressure for example of about 10 ^{~ 7} mbar, the maximum pumping speed to achieve the vacuum in the chamber being 900 L / s with an enclosure initially filled with nitrogen;

- not more than 6 cathodes with a diameter of 3 inches (or 76 mm), or

2 cathodes with a diameter of 6 inches (or 152 mm) and 2 cathodes with a diameter of

3 inches (or 76 mm);

each deposit will be made by magnetron sputtering from a metal target, for example Zr, Ta, W, or Ce, with an applied power of 0.3 to 2 W / cm ² , in RF mode or in DC mode, preferably in pulsed DC mode, for example at 50 kHz for 2 μ,, in order to obtain high deposition rates, for example from 3 to 30 nm / minute for the industrialization of the process described as reactive. In order to oxidize and / or hydrate the materials in thin layers, the plasmagenic gas will consist of a mixture of argon and oxygen and / or water vapor.

It should be noted that according to one of the advantageous features of the invention, the electrochromic materials can be prepared by a process of PVD, for example by reactive magnetron sputtering, from a single tungsten target with in particular a controlled water vapor content in the deposition chamber.

In this case where one operates with a single target of tungsten, the two electrochromic materials HxWOs.nl-hO will be obtained with an argon content generally fixed by the flow meter between 70 and 80 sccm, preferably 80 sccm ("standard cubic centimeter per minute ") with a partial pressure of water vapor generally between 5 and 10%, preferably 8%.

The deposit parameters will be for example:

a power density applied to the tungsten target of

0.3 to 2 W / cm ² ;

a cathode voltage of 335 to 500 volts;

a plasmagene gas pressure such as a mixture of argon and water vapor of 2.3 to 10 ^-2 mbar, for example 2.55 10 ^-2 mbar;

the power applied to the target is always proportional to the partial pressure of water vapor.

In addition, the substrate will generally be heated between 100 and 300 ° C, preferably between 150 and 200 ° C to enhance the crystallization of the active material during deposition while preserving the properties of the underlying layers.

The device according to the invention, inorganic, robust and simplified design which can in particular operate in the medium infrared finds particular application in the thermal protection of satellites.

For example, it will be possible to use satellite "patches" composed of several electrochromic "all-solid" devices according to the invention to replace energy-consuming mechanical shutters.

The invention will now be described with reference to the following examples, given by way of illustration and not limitation. EXAMPLES

Example 1

In this example, a 600 nm thick layer of the electrochromic material HxWOs.nhhO-c is deposited by magnetron sputtering where x is between 0.2 and 1 (0.2 and 1 inclusive), and n is a integer from 1 to 2, on an electronic glass insulating substrate. This crystallized, protonated and hydrated tungsten oxide is deposited at low power, namely at 0.6 W / cm ² , from a metal tungsten target. Spraying is carried out in DC mode pulsed in an argon / water mixture at room temperature without heating the substrate, or with heating of the substrate.

Several layers are thus made at room temperature or by heating the substrate at different temperatures, namely 150 ° C, 200 ° C, 250 ° C, and 350 ° C.

The deposited layers are activated in a protonated liquid medium

H ₃ PO ₄ - 0.1 M.

Figures 2 and 3 respectively illustrate the modulation of the infrared reflection variation and electronic conduction properties of the active material HxWOs.nh Oc where x is between 0.2 and 1 (0.2 and 1 inclusive), and n is a integer from 1 to 2 depending on its glass deposition temperature by magnetron sputtering.

For a layer with a thickness of 600 nm, the best contrasts in the infrared (focused in bands II and III of the IR range) are obtained with temperatures of 150 and 200 ° C, corresponding to resistivity values between 2 10 ^{~ 2} and 4 10 ¹ Q.cm.

Recall that the band II of the infrared range extends between the wavelengths of 3 and 5 μιη, and that the band III of the infrared range extends between the wavelengths of 8 and 12 μιη. This layer has the most interesting reflectivity modulations in band II (18.1%) and in band III (25.6%) associated with a resistivity of 3.8 10 ¹ Q.cm, for a deposition temperature. 150 ° C. Example 2

FIG. 4 shows that a reflection modulation in the infrared range is actually obtained on the front face of the "all-solid" stack of a device according to the invention.

This device is a device such as that described in Figure 1, and which has no encapsulation layer (8).

It comprises on the front face a layer of active material HxWOs.nhh0- c thickness 0.6 μιη, the intrinsic properties are shown in Figures 2 and 3; an electrolyte layer ZrC 2 .nhhO with a thickness Ιμιη; and a HxWOs.nhhO proton reservoir layer with a thickness of 0.6 μιη; on an ITO layer and a glass substrate.

All the layers of the device were deposited by magnetron sputtering.

More precisely, in this example, the optical contrast obtained by controlling the device between + 3V (absorbing state) or -3V (reflective state) with a protonation ratio exchanged reversibly between the active material is illustrated.

with values of x from 0.2 to 0.5, crystallized, and the proton reservoir HxWOs.nhhO with values of x from 0 to 0.3; of identical thickness 600 nm. The proton conduction between these two electrochromic materials is ensured by the electrolyte layer ZrC ^ .nhhO of thickness Ι μιη.

The active layer of HxWOs.nhhO-c with values of x from 0.2 to 0.5 is deposited in the same magnetron sputtering chamber as the proton storage layer HxWOs.nhhO with values of x from 0 to 0 , 3; without opening the chamber, using the same tungsten target, with the method of deposition in DC pulsed reactive mode, characterized by heating for the crystallized active material, and by a high working pressure, namely for example a pressure P (Ar + O ₂ ) = 2.3 10 ^-2 mbar, conferring on the materials sufficient porosity for their reactivity to proton intercalation (represented by the intercalation rate x in H _x W03).

In the initially deposited active layer, a proton level of x = 0.2 is irreversibly inserted for electronic conduction purposes, whereas in the storage layer a proton level of x = 0.3 is inserted and released for the second time. active layer, which can therefore reversibly modulate its optical response with a value of x between 0.2 and 0.5.

The modulation of the optical response in the infrared is ensured by the variation of the intercalation rate "x" which corresponds to the proton level in the active material HxWOs.nl-hO-c. This modulation of the total reflection of the device is reversible by applying a potential to the device between the current collector of the rear face (ITO) and the active material.

The application of a +/- 3 V potential by cyclic voltammetry makes it possible to obtain an optical contrast in the infrared.

The device made with 600 nm of active material in the front face has a reflectivity modulation of 13% in band II and 31% in band III when "x" varies from 0.2 to 0.5. The switching time necessary to obtain a maximum contrast is of the order of ten minutes for an active surface of 4 cm ² .

Claims

1. All-solid electrochromic device with controlled infrared reflection or emission, in particular of the electrocontrollable type, comprising, preferably consisting of a stack, said stack comprising successively from a rear face to a front face exposed to infrared rays:

a) a substrate made of an electronically conductive material, or a substrate made of an electronically conductive material covered with a layer of an electronically conductive material, said substrate made of an electronically conductive material or said layer of an electronically conductive material forming a first electrode;

b) a layer of a first electrochromic proton storage material;

c) a layer of a proton-conducting and electronic-insulating electrolyte;

d) an electronically self-active layer with variable reflection in the infrared (preferably in the mid-infrared) and electronic conductor, of a second preprotonated electrochromic material with variable proton intercalation rate, chosen from preprotonated tungsten oxide and crystallized H _x W03-c, where x which represents the proton content of the material is between 0.2 and 1 (0.2 and 1 inclusive), and the preprotonated and crystallized hydrated tungsten oxide HxWOs.nl-hO -c where x which represents the proton content of the material is between 0.2 and 1 (0.2 and 1 inclusive) and n is an integer from 1 to 2, the content of irremovable, non-exchangeable, irreversibly incorporated protons , said second electrochromic material always being equal to 0.2;

e) optionally, a protective layer, transparent to infrared rays, made of an inorganic material; said stack not comprising a sub-stoichiometric tungsten oxide layer W03- _y where y is between 0.2 and 1.

2. All-solid electrochromic device with controlled infrared reflection or emission, in particular of the electrocontrollable type, comprising, preferably consisting of, a stack, said stack consisting successively from a rear face to a front face exposed to infrared rays in:

b) a layer of a first electrochromic proton storage material;

c) a layer of a proton-conducting and electronic-insulating electrolyte;

d) an electronically self-active layer with variable reflection in the infrared (preferably in the mid-infrared) and electronic conductor, of a second preprotonated electrochromic material with variable proton intercalation rate, chosen from preprotonated tungsten oxide and crystallized H _x W03-c, where x which represents the proton content of the material is between 0.2 and 1 (0.2 and 1 inclusive), and the preprotonated and crystallized hydrated tungsten oxide H _x W03.nH20 -c where x which represents the proton content of the material is between 0.2 and 1 (0.2 and 1 inclusive) and n is an integer from 1 to 2, the content of irremovable, non-exchangeable, irreversibly incorporated protons of the second preprotonated electrochromic material always being equal to 0.2;

e) optionally, a protective layer, transparent to infrared rays, made of an inorganic material.

3. Device according to claim 1 or 2, in which said substrate (4) is made of an electronic conductive material chosen from materials mechanically and chemically resistant to stresses from the external environment and chemically compatible with respect to proton operation and in particular chemically compatible with the first electrochromic proton storage material, preferably said electronic conductive material is chosen from metals such as aluminum, platinum or chromium, and their alloys.

4. Device according to claim 1 or 2, wherein said substrate (4) is made of a non-electronic conductive material chosen from materials mechanically and chemically resistant to stresses from the external environment and chemically compatible with proton operation and in particular chemically compatible with the first electrochromic proton storage material, preferably said electronic non-conductive material is chosen from glasses and mechanically and chemically resistant organic polymers, such as Poly (ethylene terephthalate) or PET .

5. Device according to any one of claims 1 to 4, in which the layer of an electronic conductive material is made of a material chosen from materials mechanically and chemically resistant to stresses from the external environment, and chemically compatible with respect to proton operation and in particular chemically compatible with the first electrochromic proton storage material, preferably said electronic conductive material is chosen from metals such as aluminum, platinum, chromium and their alloys; and conductive metal oxides electronics such as indium tin oxide or ITO and fluorine doped tin oxide or FTO.

6. Device according to any one of the preceding claims, in which the first electrochromic proton storage material is chosen from electrochromic proton storage materials chemically compatible with proton operation, in particular chemically compatible with screw of the proton conducting and electronic insulating electrolyte, preferably the first electrochromic proton storage material is chosen from metal oxides and hydrated metal oxides, preferably amorphous, such as amorphous tungsten oxide H _x W03 and hydrated amorphous tungsten oxide HxWOs.nl-hO, where x is between 0 and 1, and n is an integer from 1 to 2, and mixtures of two or more of said oxides.

7. Device according to claim 6, in which the first electrochromic proton storage material is chosen from preprotonated amorphous tungsten oxide H _X W03 where x is between 0.2 and 1, preferably between 0.2 and 0, 5, and hydrated preprotonated amorphous tungsten oxide where x is between 0.2 and 1, preferably between 0.2 and 0.5, and n is an integer from 1 to 2.

8. Device according to any one of the preceding claims, in which the proton conducting and electronic insulating electrolyte is chosen from proton conducting and electronic insulating electrolytes chemically compatible with respect to proton operation, in particular chemically compatible (inert ) with respect to crystallized tungsten oxide H _x W03-c (protonated tungsten oxide) or hydrated crystallized tungsten oxide HxWOs.nl-hO-c, preferably the electrolyte proton conductor and electronic insulator is chosen from preferably amorphous hydrated metal oxides such as amorphous hydrated tantalum oxide Ta ₂ Os, amorphous hydrated zirconium oxide and mixtures of two or more of said oxides.

9. Device according to any one of the preceding claims, in which the possible protective layer transparent to infrared rays is made of a material chosen from materials compatible with proton operation, in particular chemically compatible with vis crystallized tungsten oxide H _x W03-c or hydrated crystallized tungsten oxide H _x W03.nH ₂ 0-c, preferably the possible protective layer transparent to infrared rays is made of a material chosen from non-toxic inorganic materials, preferably among the oxides of metals and metalloids, preferably dense, such as cerium oxide Ce0 ₂ , yttrium oxide Y ₂ Û3, silica Si0 ₂ and mixtures of two or plus said metal oxides or metalloids.

10. Device according to any one of the preceding claims, wherein the substrate has a thickness of 0.175 mm to 1 mm.

11. Device according to any one of the preceding claims, in which the layer of an electronically conductive material which covers the substrate of an electronically non-conductive material has a thickness of 50 to 150 nm.

12. Device according to any one of the preceding claims, in which the layer of a first electrochromic proton storage material has a thickness of 0.5 to 3 μιη, preferably of 0.6 to 1.4 μιη.

13. Device according to any one of the preceding claims, in which the layer of a proton-conducting and electronic-insulating electrolyte has a thickness of 0.2 to 1.2 μιη, preferably 0.4 to 1 μιη.

14. Device according to any one of the preceding claims, in which the layer of a second electrochromic material has a thickness of 0.5 to 3 μιη, preferably of 0.6 to 1.4 μιη.

15. Device according to any one of the preceding claims, in which the protective layer transparent to infrared rays has a thickness of 0.01 to 0.1 μιη, preferably of 0.02 to 0.05 μιη.

16. Layer of preprotonated electrochromic material with variable proton intercalation rate, chosen from preprotonated and crystallized tungsten oxide H _x W03-c where x is between 0.2 and 1, and preprotonated and crystallized tungsten oxide hydrated HxWOs.nl-hO-c, where x which represents the proton content of the material, is between 0.2 and 1, and n is an integer from 1 to 2, the content of immovable, non-exchangeable, incorporated protons irreversibly of said preprotonated electrochromic material always being equal to

0.2.

17. Method for preparing the layer of preprotonated electrochromic material with variable proton intercalation rate according to claim 16, chosen from preprotonated and crystallized tungsten oxide H _x W03-c where x which represents the proton content of the material is between 0.2 and 1, and the preprotonated and crystallized hydrated tungsten oxide HxWOs.nl-hO-c where x which represents the proton content of the material is between 0.2 and 1, and n is an integer from 1 to 2, the content of irremovable, non-exchangeable, irreversibly incorporated protons of said preprotonated electrochromic material at intercalation rate variable proton being always equal to 0.2, in which the following successive steps are carried out:

a layer of preprotonated electrochromic material is deposited on a substrate or on a previously deposited layer, chosen from preprotonated tungsten oxide H _x W03-c where x is 0.2, and hydrated preprotonated tungsten oxide HxWOs.nl -hO-c where x is 0.2 and n is an integer from 1 to 2, by a physical vapor deposition or PVD process using a metallic tungsten target and a deposition atmosphere containing water vapor , the conditions of the PVD process being such that the water vapor decomposes into oxygen atoms and reactive protons to oxidize and protonate the tungsten;

simultaneously heating said layer of preprotonated electrochromic material to a temperature such as preprotonated tungsten oxide H _x W03-c where x is 0.2, and hydrated preprotonated tungsten oxide H _x W03.nH20-c where x is 0.2, and n is an integer from 1 to 2 crystallize and the protons contained at an x content of 0.2 become immovable, inexchangeable.

18. Method according to claim 17, in which, among the conditions of the PVD process which allow the water vapor to decompose into oxygen atoms and reactive protons to oxidize and protonate tungsten, there is the condition of 'a power applied to the target proportional to the partial pressure of water vapor.

19. Method according to claim 17 or 18, in which said layer of preprotonated electrochromic material is heated to a temperature of 100°C to 300°C, preferably to a temperature of 150°C to 250°C.

20. Process for preparing the device according to any one of claims 1 to 15, in which the following successive steps are carried out:

a) a layer of a first electrochromic proton storage material is deposited on a substrate of an electronically conductive material, or on a layer of an electronically conductive material placed on a substrate of an electronically non-conductive material, said substrate of an electronically conductive material or said layer of an electronic conductive material forming a first electrode;

b) a layer of a proton conducting and electronic insulating electrolyte is deposited on the layer made of a first electrochromic proton storage material;

c) we prepare, on the layer deposited during step b), an electronically self-active layer with variable reflection in the infrared and electronic conductor of a second preprotonated electrochromic material with variable proton intercalation rate, chosen from preprotonated and crystallized tungsten oxide H _x W03-c where x is between 0.2 and 1 (0.2 and 1 inclusive) and hydrated preprotonated and crystallized tungsten oxide HxWOs.nl-hO-c where x is between 0.2 and 1 (0.2 and 1 inclusive) and n is an integer from 1 to 2, the content of irremovable, non-exchangeable, irreversibly incorporated protons of the second preprotonated electrochromic material always being equal to 0.2 ;

d) optionally, a protective layer, transparent to infrared rays, made of an inorganic material, is deposited on the variable reflection layer in the infrared of a second preprotonated electrochromic material.

21. Method according to claim 20, in which the layers are deposited by a physical vapor deposition or PVD process chosen from cathode sputtering, laser ablation and evaporation.

22. Method according to claim 21, in which all the layers are deposited by the same physical vapor deposition process, preferably by reactive magnetron cathode sputtering.

23. Method according to claim 22, in which all the steps are carried out in the same vacuum enclosure without opening the enclosure between each of the steps.

24. Use of the device according to any one of claims 1 to 15, for the thermal protection of an object, in particular a satellite.