WO2019030273A1

WO2019030273A1 - Compositions comprising dispersed nanoparticles

Info

Publication number: WO2019030273A1
Application number: PCT/EP2018/071484
Authority: WO
Inventors: Jens Roeder; Michael Goebel; Birgit GERKE; Daniel WALDMANN; Sandro Pagano; Ralf Noerenberg; Garo Khanarian; Fabian Seeler; Erich Beck; Maraike Ahlf
Original assignee: Basf Se
Priority date: 2017-08-09
Filing date: 2018-08-08
Publication date: 2019-02-14
Also published as: TW201920594A

Abstract

Described are compositions comprising dispersed nanoobjects, processes for preparing a layer comprising such nanoobjects on a surface of a solid substrate and articles comprising such layers.

Description

Compositions comprising dispersed nanoparticles

The present invention relates to compositions (also referred to as inks) comprising nanoobjects, to a process for preparing a layer comprising nanoobjects on a surface of a solid substrate, and to articles comprising a solid substrate having a surface and a layer comprising nanoobjects arranged on said surface of said substrate.

Electronic devices e.g. optoelectronic devices or electrochromic devices often contain functional layers comprising nanoobjects, e.g. nanoobjects comprising an electrochromic material or fluorescing semiconducting nanoobjects (also referred to as quantum dots). Such functional layers are commonly prepared by wet processing techniques wherein a liquid composition (commonly referred to as an "ink") comprising suspended nanoobjects is applied to a surface of a solid substrate. Compositions comprising suspended nanoobjects are also used for preparing any other objects and formulations comprising nanoobjects.

It is commonly known that nanoobjects, when dispersed in a liquid phase are prone to agglomeration and/or settling. A variety of proposals for solving this problem is disclosed in the prior art. For instance, WO 2016/128133 A1 proposes addition of dispersing agents in the form of metal salts to inks comprising nanoobjects. Preferred salts are formiates, acetates, citrates, oxalates, nitrates and halogenides of metal cations from the group consisting of Zn, Al, Y, Pb, Bi Cu, Ni, Co, Fe, Mn, Cr, V, Ti, La, Mg, Ca, Sr and Ba. Related art is also

WO 2016/128133 A1

WO 2014/148823 A1

WO 2017/153406 A1

WO 2017/137396 A1.

There is an ongoing demand for compositions comprising dispersed nanoobjects wherein agglomeration and/or settling of said nanoobjects is effectively suppressed over a long duration, even in case of a high concentration and/or small size of said dispersed nanoobjects.

According to a first aspect of the present invention, there is provided a composition comprising

(a) nanoobjects

comprising one or more compounds selected from the group consisting of

oxides, sulfides, selenides, and tellurides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon

and

compounds of formula (I)

wherein A is a monovalent organic cation or an alkali metal cation,

D is Pb, Sn, or Ge,

X is CI, Br, or I,

i is an integer from 0 to 6

(b) one or more salts of formula (II)

M^a+(Z )a (II)

wherein

M^a+ is a metal cation wherein a is 2, 3, 4 or 5, and

Z^" is a weakly coordinating anion whose corresponding acid has an acidity higher than the acidity of 100 % sulfuric acid

(c) optionally a carrier liquid having 0 to 8 carbon atoms per molecule. Surprisingly it has been found that in a composition comprising dispersed nanoobjects (a) as defined above, metal salts (b) according to formula (II) as defined above are capable of effectively suppressing agglomeration and/or settling of said dispersed nanoobjects (a) over a long duration, even in case of high concentrations of said nanoobjects (a), without affecting other properties of said nanoobjects and without detrimental effects towards other constituents of said composition. Furthermore, it has been found that advantageously said metal salts of formula (II) do not detrimentally affect the properties of a layer comprising said nanoobjects (a) obtainable from said composition by wet-processing techniques.

In certain cases, a composition according to the present invention consists of constituents (a) and (b) as defined above.

A composition according to the present invention which contains a carrier liquid (c) is in the form of a suspension, also referred to as slurry. In the context of certain technical application fields, such composition is also referred to as an ink. Preparation of suspensions is known in the art. The term "suspension" denotes a dispersion comprising a continuous phase (in the literature sometimes referred to as an external phase e.p.) that is liquid and at least one dispersed phase (in the literature sometimes referred to as an internal phase i.p.) that is solid and does not dissolve in said continuous phase which is liquid. In a suspension which forms a composition according to the present invention, the nanoobjects (a) form a dispersed phase, which is dispersed within the liquid external phase. The external liquid phase consists of the carrier liquid (c) and - if present- any constituents which are dissolved in said carrier liquid (c) and any further liquids mixed with said carrier liquid. Without wishing to be bound by theory it is assumed that at least a portion of said metal salts of formula (II) is physisorbed on the surfaces of said nanoobjects (a).

The constituents of the composition according to the invention are now described in detail. According to ISO/TS 27687:2008 (as published in 2008), the term "nanoobject" refers to an object having one, two or three external dimensions in the nanoscale, i.e. in the size range from approximately 1 nm to 100 nm.

According to ISO/TS 27687:2008, nanoobjects having one external dimension in the nanoscale, while the other two external dimensions are significantly larger, are generally re- ferred to as nanoplates. Said one external dimension in the nanoscale corresponds to the thickness of the nanoplate. The two significantly larger dimensions differ from the nanoscale dimension by more than three times. The two larger external dimensions are not necessarily in the nanoscale. Another common term for denoting a nanoobject having one external dimension in the nanoscale, while the other two external dimensions are significantly larger, is "nanoflake".

According to ISO/TS 27687:2008, nanoobjects having two similar external dimensions in the nanoscale, while the third external dimension is significantly larger, are generally re- ferred to as nanofibers. The third significantly larger dimension differs from the nanoscale dimensions by more than three times. The largest external dimension is not necessarily in the nanoscale. Said largest external dimension corresponds to the length of the nanofibers. Nanofibers typically have a cross section close to circular shape. Said cross section extends perpendicularly to the length. Said two external dimensions which are in the na- noscale are defined by the diameter of said circular cross section.

Electrically conductive nanofibers are also referred to as nanowires. Hollow nanofibers (irrespective of their electrical conductivity) are also referred to as nanotubes. Nanoobjects having two similar external dimensions in the nanoscale, while the third external dimension (length) is significantly larger, which are rigid (i.e. not flexible) are commonly referred to as nanorods. Nanoobjects having two similar external dimensions in the nanoscale, while the third external dimension (length) is significantly larger, and have a cross section close to rectangular shape extending perpendicularly to the length, are commonly referred to as nanoribbons.

According to ISO/TS 27687:2008, nanoobjects having all three external dimensions in the nanoscale, wherein the length of the longest axis and the length of the shortest axis of the nanoobject differ not significantly, are generally referred to as nanopartides. The length of the longest axis and the length of the shortest axis differ by not more than three times.

Approximately isometric nanopartides, i.e. the aspect ratio (longest : shortest direction) of all three orthogonal external dimensions is close to 1 , are commonly referred to as nano- spheres.

Preferably, the nanoobjects of constituent (a) of the present invention are nanopartides. Preferred nanopartides are approximately isometric, i.e. the aspect ratio (longest : shortest direction) of all 3 orthogonal external dimensions is in the range of from 1 to 2. Especially preferred nanopartides are nanospheres. Particularly preferred nanopartides are primary particles having a primary particle diameter of 1 nm to 100 nm, preferably 3 nm to 50 nm (measured by nitrogen absorption, X-ray diffraction or transmission electron microscopy). Preferred are nanopartides having a pri- mary particle diameter of less than 20 nm, more preferably less than 15 nm, further preferably 12 nm or less. According to DIN 53206-1 : 1972-08, the term "primary particles" refers to entities which are discernible as individuals by means of optical microscopy or transmission electron microscopy. Advantageously, the nanoobjects are nanoparticles which in suspension have a hydrodynamic size D90 of less than 100 nm (measured by dynamic light scattering or centrifugal sedimentation techniques) and a median value (D50) of the hydrodynamic size of 30 nm or less.

Said nanoobjects (a) comprise, preferably consist of, one or more compounds selected from the group consisting of

and

- compounds of formula (I)

wherein A is a monovalent organic cation or an alkali metal cation,

D is a divalent metal selected from the group consisting of Pb, Sn, or Ge,

X is CI, Br, or I,

i is an integer from 0 to 6.

Preferably, in formula (I) i = 0. Preferred compounds of formula (I) are CsPbC , CsPb , CsPbBrs, CsSnCIs, CsSnls, CsSnB_r3, CsGeC , CsGels, CsGeBrs.

Sulfides, selenides, and tellurides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon and materials of the above-defined formula (I) are e.g. suitable materials for quantum dots. As used herein, "elements of groups 12, 13 and 14" refer to elements of groups 12, 13 and 14 of the periodic table of the elements according to lUPAC notation.

Among the sulfides and selenides, those of Zn, Cd, and Pb are most preferred.

In preferred compositions according to the present invention, said nanoobjects (a) com- prise one or more electrochromic compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon. More preferably, said nanoobjects (a) consist of one or more electrochromic compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon.

Electrochromic materials are characterized by an ability to change their optical properties, reversibly, and persistently, when a voltage is applied across them (see Claes G. Granqvist, Solar Energy Materials & Solar Cells 99 (2012) 1-13). This ability is herein also referred to as the "electrochromic effect". A change of the optical absorption of the electrochromic material occurs when electrons are transferred to or away from the electrochromic material, along with charge balancing ions entering from an adjacent electrolyte. Certain electrochromic materials have the property of exhibiting a change, evocation, or bleaching of color (in the visible range of the electromagnetic spectrum) as effected either by an electron- transfer (redox) process or by a sufficient electrochemical potential (see Mortimer, R. J.: "Electrochromic materials", Annu. Rev. Mater. Res. 201 1. 41 :241-68). However, as used herein, the term "electrochromic material" is not limited to materials exhibiting a change, evocation, or bleaching of color (in the visible range of the electromagnetic spectrum). Thus, materials changing their optical absorption, e.g. in the UV or IR range of the electromagnetic spectrum without a visible color change, are herein also referred to as "electro- chromic".

Electrochromic metal oxides are known in the art, see e.g. Mortimer, R. J.: "Electrochromic materials", Annu. Rev. Mater. Res. 201 1. 41 :241-68 and Granqvist, C. G.: "Oxide electro- chromics: An introduction to devices and materials", Solar Energy Materials & Solar Cells 99 (2012) 1-13. Preferably said nanoobjects (a) comprise or consist of one or more electrochromic compounds are selected from the group consisting of oxides of Ti, Ni, Zn, Y, Zr, Nb, Mo, Cd, Ce, Hf, Ta, W, Ag, La, Pr, Nd, Sm, Eu, Si, Sn, Pb, In, V and Ir. More preferably said nanoobjects (a) are nanoparticles (as defined above) comprising, preferably consisting of, one or more electrochromic compounds selected from the group consisting of oxides of Ti, Ni, Zn, Y, Zr, Nb, Mo, Cd, Ce, Hf, Ta, W, Ag, La, Pr, Nd, Sm, Eu, Si, Sn, Pb, In, V and Ir.

More preferably, said nanoobjects comprise one or more oxides of nickel, preferably consist of one or more oxides of nickel. Especially preferably, said nanoobjects (a) are nanoparticles comprising one or more oxides of nickel, preferably consisting of one or more oxides of nickel. Preparation of nanoobjects (a) comprising one or more electrochromic metal oxides is known in the art. For instance, said nanoobjects (a) are nanoparticles synthesized by a gas phase pyrolysis process, preferably flame spray synthesis. Such nanoparticles are commercially available. Said metal salts consist of metal cations M^a+ wherein a is 2, 3, 4 or 5, and anions Z^~ which are weakly coordinating anions whose corresponding acid has an acidity higher than the acidity of 100 % sulfuric acid.

The term "weakly coordinating anion" is known in the art, see e.g. I. Krossing and I. Raabe, Angew. Chem. Int. Ed. 2004, 43, 2066 - 2090. Weakly coordinating anions (sometimes referred to as non-coordinating anions) are stable on their own and do not have a propensity to donate electrons to an electron acceptor. These anions readily release their respective cations because their negative charge is delocalized over a large area of non-nucleo- philic and chemically robust moieties. The coordinating ability of each anion is limited by its most basic site; it will always coordinate with its most nucleophilic, sterically accessible moiety. Therefore, the acidity of the corresponding acid is a measure for the coordinating ability of the anion.

Acids having an acidity higher than the acidity of pure sulfuric acid (100 % sulfuric acid) are known in the art and are also referred to as "superacids".

The term acidity, as used herein, refers to the acidity in the solvent 1 ,2-dicloromethane according to the equilibrium superacidity scale proposed by A. Kutt et al., J. Org. Chem. Vol. 76, No. 2, 201 1 and may be determined by the method described therein.

Without being bound to theory, it is believed that the metal salts of formula (II) as defined above act as dispersing aids for the nanoobjects (a) and are at least partly physisorbed on the surface of the nanoobjects (a), and may be partly dissolved in the carrier liquid (c) of the suspension. The term "dispersing aid" as used herein denotes a substance which facilitates the separation of suspended particles and acts to prevent or suppress agglomeration or settling of said particles. In the context of the present invention the term "dispersing aid" is used for metal salts of formula (II) as defined herein which stabilize said suspended nanoobjects (a). In the composition according to the present invention, the surfaces of the nanoobjects (a) are at least partly coated with physisorbed metal salts of formula (II). The term physisorp- tion, as used herein, defines adsorption in which the forces involved are intermolecular forces (van der Waals or electrostatic forces) and which do not involve a significant change in the electronic orbital patterns of the species involved. In the context of the present application, "physisorption" denotes the adsorption of a molecule or ion on a surface by either electrostatic or van der Waals attraction. In contrast to chemisorption, a physisorbed molecule or ion does not alter its chemical properties upon adsorption. Accordingly, by physisorption covalent bonds are neither formed nor broken nor are atoms ionized or ions deionized or subject to a change of their charge.

Coating of nanoobjects (a) by said one or more metal salts of formula (II) may be achieved by procedures known in the art. For instance, said carrier liquid (c) and said nanoobjects (a) are combined, for example by mixing, ultrasonication or ball milling. To the obtained initial suspension, one or more metal salts of formula (II) as defined above are added. Coating of the nanoobjects (a) with the one or more metal salts of formula (II) as defined above takes place during mixing at room temperature or upon heating. Alternatively, said carrier liquid (c) and said one or more metal salts of formula (II) are combined, for example by mixing. To the obtained initial solution of one or more metal salts of formula (II) in the carrier liquid (c), the nanoobjects (a) are added. Coating of the nanoobjects (a) with the one or more metal salts of formula (II) as defined above takes place during mixing at room temperature or upon heating.

Preferably in said salts of formula (II) said metal cation M^a+ is a cation of a metal selected from the group consisting of transition metals, rare earth metals, Mg, Ca, Sr, Ba, Al, In, Ga, Sn, Pb, Bi, Zn, Cd, and Hg. Preferably, said cation M^a+ is a cation of a metal selected from the group consisting of Ni, Cu, Zn, Al, In, Sc, La, Ce and Y.

Preferably in said salts of formula (II) said anion Z^" is selected from the group consisting of (Z-1 ) [BX₄]^" wherein

X is selected from F, -OTeFs, -CN and R

(Z-2) [X3B-E-BX3]- wherein

X is selected from F, -OTeFs, -CN and R

and E is selected from F and CN

(Z-3) [CBiiHi2-mXm]- wherein

X is selected from F, CI, Br, I and R;

and m is an integer selected from the range of 1 to 12

(Z-4) [CBgH-io-mXm]^" wherein

X is selected from F, CI, Br, I and R; and m is an integer selected from the range of 1 to 10

(Z-5) [AIX₄]- wherein

X is selected from F, CI, Br, I, -OR, R, and -OC{X'_mR3-m} wherein m is an integer selected from the range of 0 to 3 and X' is selected from F, CI, Br, I and -OR

(Z-6) [X3AI-E-AIX3]- wherein

X is selected from of F, CI, Br, I, -OR, R, and -OC{X'_mR3-m} wherein m is an integer selected from the range of 0 to 3 and X' is selected from F, CI, Br, I and -OR and E is selected from CN and F

(Z-7) [EX₆]- wherein

E is selected from P, As and Sb

X is selected from F, CN, -OTeFs and R

(Z-8) [X5E-A-EX5]^" wherein

E is selected from P, As and Sb

X is selected from F, CN, -OTeFs, and R;

A is selected from F and CN

(Z-9) [E(S0₂X)m]- wherein

X is selected from F and R;

E is selected from O, N and C

m is an integer selected from the range of 1 to 3; m = 1 for E = O; m = 2 for E = N; m = 3 for E = C;

(Z-10) [N(OPR₂)₂]-

(Z-13) N(CN)₂- wherein in the anions selected from the group consisting of (Z-1 ) to (Z-13) R, if present, is selected from the group consisting of

CnH_2n+i pFp, wherein n is an integer selected from the range of 1 to 16 and p is an integer selected from the range of 0 to (2n + 1 )

CnH(_2n-i) pFp, wherein n is an integer selected from the range of 2 to16 and p is an integer selected from the range of 0 to (2n - 1 ) C_nH(2n-3)-pFp, wherein n is an integer selected from the range of 2 to 16 and p is an integer selected from the range of 0 to (2n - 3)

C6H5-n-pFp(CH3 qFq)n, wherein n is an integer selected from the range of 0 to 5, p is an integer selected from the range of 0 to 5 and q is an integer selected from the range of 0 to 3.

Preferably in said salts of formula (I I) said cation M^a+ is selected from the above-defined preferred cations M^a+, and the anion Z^~ is selected from the above-defined preferred anions Z^".

Metal salts (b) of formula (I I) having any anion of hexafluorophosphate and tetrafluorobo- rate are in certain cases not preferred, see below.

Preferably, the metal salt (b) of formula (I I) is not selected from the group consisting of iron(l l) perchlorate and tin(l l) perchlorate. More preferably, when the anion of the metal salt (b) of formula (I I) is perchlorate CIC ^", the cation is not a cation of a metal selected from the group consisting of Fe, Sn, Mn, Co and Ce. In certain cases, it is preferred that the metal salt (b) of formula (II) said anion Z^" is selected from the group consisting of (Z-1 ) to (Z-12) as defined in claim 1 .

Preferred anions are above-defined anions (Z-9) wherein X is F or C_nH2n+i-pF_p, herein n is an integer selected from the range of 1 to 16 and p is an integer selected from the range of 0 to (2n + 1 ). Preferably said metal salts of formula (I I) are selected from the group consisting of scandium bis(trifluoromethane)sulfonimide, yttrium bis(trifluoromethane)sulfonimide, aluminum bis(trifluoromethane)sulfonimide, lanthanum bis(trifluoromethane)sulfonimide, cerium bis(trifluoromethane)sulfonimide, nickel bis(fluorosulfonyl)imide, copper bis(fluorosul- fonyl)imide, zinc bis(fluorosulfonyl)imide, yttrium trifluoromethylsulfonate, aluminum trifluo- romethylsulfonate, lanthanum trifluoromethylsulfonate, cerium trifluoromethylsulfonate, and yttrium fluorosulfonate.

It is preferred that the metals M of the metal salts of formula (I I) differ from the metals of the metal oxides, metal sulfides, metal selenides, and metal tellurides present in the na- noobjects (a) dispersed in said composition. Preferably, in a composition according the present invention, the molar percentage of metal ions M^a+ of the metal salts (b) of formula (II) is in the range of from 0.02 to 6 mol%, based on the total amount of

the mols of metal in the metal ions M^a+ of the metal salts (b) of formula (II)

- and the total amount of mols of metals of the metal compounds in the nanoobjects (a).

Metal salts of formula (II) as defined above are commercially available.

The carrier liquid (c) is merely a vehicle for wet processing and usually does not remain in the layer to be formed from the above-defined composition. Preferably said carrier liquid (c) has a polarity index > 4 according to the polarity scale, based on the polarity index of water being 9 (V.J. Barwick, Trends in Analytical Chemistry, vol. 16, no. 6, 1997, p.293ff, Table 5).

Preferably, said carrier liquid has a boiling point of less than 120 °C. The boiling point refers to the standard pressure of 101.325 kPa. Said carrier liquid is not polymerizable.

Preferably said carrier liquid is selected from the group consisting of water, alcohols, amines, carbonic acids, esters, ketones, organic carbonates, polyethers, sulfides and ni- triles and mixtures thereof. More preferably, said carrier liquid is selected from the group consisting of water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, iso- butanol, tert.-butanol, 2-butanone, 2-pentanone, methyl isobutyl ketone, dimethyl carbonate, ethyl methyl carbonate, 1 ,2-dimethoxy-ethane, acetonitrile, pyridine, propionitrile, dimethylamine, formic acid, acetic acid, ethyl acetate, dimethoxyethane, acetone, dimethyl carbonate, dioxane, trifluoromethyl methyl carbonate, ethyl methyl carbonate, 2-methyltet- rahydrofuran, chloroform and mixtures thereof. Preferably, in a composition according to the invention

(a) the amount of nanoobjects comprising one or more compounds as defined above is in the range of from 0.1 wt.-% to 27 wt.-%, preferably 0.5 wt.-% to 12 wt.-%,

(b) the amount of metal salt of formula (II) as defined above is in the range of from 0.001 wt.-% to 2 wt.-%, preferably 0.01 wt.-% to 1.1 wt.-%, (c) the amount of the carrier liquid having a boiling point below 120 °C is in the range of from 72 wt.-% to 99.5 wt.-%, preferably 87 wt.-% to 99 wt.-%.

In a specific case of the above-defined first aspect of the present invention, in the composition according to the present invention

(a) said nanoobjects comprise one or more electrochromic compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon, wherein said electrochromic compounds are preferably selected from the above-defined preferred metal oxides

and

(b) said metal salts of formula (II) are as defined above, wherein said metal salts of formula (II) are preferably selected from the above-defined preferred metal salts of formula (II)

and

(c) said carrier liquid has a boiling point of less than 120 °C.

A composition according to the above-defined specific case may be used as an ink for preparing an electrochromic layer. For further details, see below.

In said composition it is preferred that the metals M of the metal salts of formula (II) differ from the metals of the metal oxides present in the nanoobjects (a) dispersed in said composition.

Preferably, in a composition according the present invention, the molar percentage of metal ions M^a+ of the metal salts (b) of formula (II) is in the range of from 0.02 to 6 mol%, based on the total amount of

the mols of metal in the metal ions M^a+ of the metal salts (b) of formula (II) and the mols of metal in the metal oxides in the nanoobjects (a).

If the above-defined molar percentage is below 0.02 %, the amount of the metal salts of formula (II) may be not sufficient to achieve the above-described effect of suppressing agglomeration and settling of the nanoobjects (a). If the above-defined molar percentage is above 6 %, in an electrochromic composite layer (see below) prepared from a composition according to the invention the amount of nanoobjects (a) comprising one or more electrochromic compounds as defined above is quite low, and may be not sufficient for achieving an appropriate electrochromic effect. Preferably a composition according to the above-defined specific case further comprises

(d) one or more kinds of polymerizable moieties.

The term "polymerizable moieties" as used herein includes polymerizable monomers and polymerizable oligomers. Said polymerizable moieties (d) are dissolved in the carrier liquid (c).

Said polymerizable moieties (d) are precursors of a polymer matrix. In the process of preparing a layer from the above-defined composition, said polymerizable moieties form a polymer matrix by polymerization on a surface of a solid substrate to which the above- defined composition has been applied. In a layer obtained from an above-defined preferred composition according to the present invention, said matrix binds and accommodates the nanoobjects (a) and the metal salt (b) and optionally further constituents (see below) within said layer, fills the voids between said nanoobjects (a), provides mechanical integrity and stability to the layer and binds the layer to the surface of the solid substrate.

Preferably said polymerizable moieties are selected from the group consisting of alkyi acry- lates, alkyi methacrylates, hydroxyalkyi acrylates, hydroxyalkyi methacrylates, vinyl chloride, vinyl fluoride, acrylonitrile, vinylidene fluoride, vinylidene chloride, hexafluoropropyl- ene, trifluoroethylene, tetrafluoroethylene, tetrahydrofurane, vinylpyrrolidone, polyisocya- nates in combination with polyols and/or diamines.

Most preferably, said polymerizable moieties are co-polymerizable monomers selected from the group consisting of alkyi acrylates and alkyi methacrylates and from the group consisting of hydroxyalkyi acrylates and hydroxyalkyi methacrylates. Herein preferably the molar ratio between the total amount of monomers selected from the group consisting of alkyi acrylates and alkyi methacrylates and the total amount of monomers selected from the group of hydroxyalkyi acrylates and hydroxyalkyi methacrylates is in the range of from 0.0002 to 50000, preferably 0.4 to 200. Preferably said polymerizable monomers are butyl acrylate and hydroxybutyl acrylates.

In cases where the polymerizable moieties (d) are polymerizable by radical polymerization, said composition preferably further comprises

(e) one or more initiators for initiating radical polymerization of said one or more kinds of polymerizable moieties. Suitable initiators are known in the art and commercially available. Preferably, said initiators are selected from the group consisting of compounds which decompose into radicals when exposed to electromagnetic irradiation.

Optionally, a composition according to the above-defined specific case further comprises (f) one or more organic polymers suspended or dissolved in the liquid external phase of the composition.

In the process of preparing a layer from the composition said polymers are incorporated in the above-defined matrix.

The polymers (f) are either dissolved in the liquid external phase of the composition, or -in case they are not soluble in said liquid phase- they are present in the form of particles which are suspended within said liquid phase.

Preferably said polymers (f) are selected from the group consisting of polyalkyl acrylates, polyalkyl methacrylates, polyhydroxyalkyl acrylates, polyhydroxyalkyl methacrylates, polyvinyl chloride, polyvinyl fluoride, polyacrylonitrile, polyvinylidene fluoride, polyvinylidene chloride, polyhexafluoropropylene, polytrifluorethylene, polytetrafluoroethylene, polytetra- hydrofuran, polyvinylpyrrolidone, polyurethanes, polyethylene oxides.

In certain cases, a composition according to the above-defined specific case, which comprises one or more polymerizable moieties (d), further comprises

(g) an aprotic organic liquid having a boiling point of 120 °C or higher. The boiling point refers to the standard pressure of 101 .325 kPa.

In the composition according to the present invention, said aprotic organic liquid (g) is mixed with the carrier liquid (c) so that both liquids form a common liquid phase in the above-defined composition. Accordingly, carrier liquid (c) and aprotic organic liquid (g) are selected to be miscible. Said aprotic organic liquid is selected to have a boiling point of 120 °C or higher, in order to allow said aprotic organic liquid (g) to remain in a layer prepared from the above-defined composition, when heat is applied during the steps of removing the carrier liquid and polymerizing the polymerizable moieties.

Said aprotic organic liquid (g) is not polymerizable. Said aprotic organic liquid is selected to be capable of allowing for dissolution and dissociation of at least one electrolyte (h) as defined below.

Preferably said aprotic organic liquid (g) is selected from the group consisting of organic carbonates, alcoholes, amides, carboxylic acid esters, ethers, polyethers, ketones, lac- tones, lactames, phosphoric acid esters, sulfones, sulfoxides, sulfonates, urea, thiourea, derivatives of urea resp. thiourea, and mixtures thereof. Derivatives of urea resp. thiourea are compounds wherein one or more of the hydrogen atoms of urea resp. thiourea are substituted. Examples are ethylene urea (2-lmidazolidon) Ν,Ν'-dimethylpropylene urea, N-(2-hydroxyethyl)ethylene urea and the corresponding thiourea derivatives. Most preferably, said aprotic organic liquid (g) is selected from the group consisting of ethylene carbonate, 1 ,2-propylene carbonate, 1 ,3-propylene carbonate, 1 ,2-butylene carbonate, 1 ,3-butylene carbonate, 1 ,4-butylene carbonate, 2,3-butylene carbonate, ethylene glycol, diethylene glycol, diethyl carbonate, gamma-butyrolactone, gamma-valerolactone, sulfolane, dimethyl sulfoxide, 1 ,3-dimethyl-3,4,5,6-tetrahydro-2(1 H)-pyrimidinone (DMPU) and mixtures thereof.

Especially preferred are ethylene carbonate, fluorinated ethylene carbonate, 1 ,2-propylene carbonate, fluorinated 1 ,2-propylene carbonate, 1 ,3-propylene carbonate, fluorinated 1 ,3- propylene carbonate and mixtures thereof.

In certain cases, a composition according to the above-defined specific case, which com- prises one or more polymerizable moieties (d) and an aprotic organic liquid (g) having a boiling point of 120 °C or higher, further comprises

(h) at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺.

If a composition according to the above-defined specific case comprises any salt of Li, Na or K dissolved in said aprotic organic liquid (g) which has a composition falling under formula (I) above, those salts are considered as electrolytes (h).

The term "electrolyte" is known in the art and denotes a substance which is capable of dissociating into mobile ions. In a layer prepared from the above-defined composition, said electrolyte (h) dissolved in said aprotic organic liquid (g) provides ionic conductivity. In the context of this disclosure, water does not belong to the electrolytes (h) as defined above. Accordingly, said electrolyte comprises at least one anion which is different from OH^" or at least one cation from the group consisting of Li⁺, Na⁺ and K⁺. Preferred electrolytes (h) are lithium salts.

Preferably, said electrolytes (h) are selected from the group consisting of lithium aluminum chloride (LiAICU); lithium hexafluorosilicate (Li2SiFe); lithium hexafluoroantimonate (LiSbFe); LiX(RS0₂)n wherein n=1 and X=0 or S, n=2 and X=N or P, n=3 and X=C or Si, and R in each case is CmH2m+i-nF_n wherein m = 0-20, n = 0-21 ; lithium fluoride (LiF); lithium nitrate (LiNCb); lithium perchlorate (LiCIC ); lithium tetrafluoroborate (L1BF4); lithium tetrakis(pentafluorophenyl)borate; lithium difluorophosphate (L1PO2F2); lithium hexafluorophosphate (LiPF6); lithium hexafluoroarsenate (LiAsFe); lithium bis(fluorosulfonyl)imide (LiN(S0₂F)₂); lithium trifluoromethylsulfonate (L1CF3SO3); LiN(S0₂CnF2n₊i)2 wherein n = 2 to 20; LiC[(C_nF2n-i )S0₂]3 wherein n = 2 to 20; Li(C_nF2n₊i )S0₂ wherein n = 2 to 20; lithium bis(trifluoromethane)sulfonimide (LiN(CF3S02)2, also referred to as lithium bis(trifluorome- thylsulfonylimide); lithium tris-trifluoromethyl sulfonylmethide (LiC(CF3S02)3); lithium bisox- alatoborate (LiB(C204)2); lithium difluoro(oxalate)borate (LiBF2(C204)); lithium difluoro(bi- soxalato)phosphate and lithium tetrafluoro(oxalate)phosphate. Preferably, said electrolyte (h) has an anion which is selected from the group consisting of anions Z^~ as defined above for the metal salts (b) of formula (II).

Preferably in a composition according to the present invention the metal salts (b) of formula (I I) do not contain any anion selected from the group consisting of hexafluorophosphate and tetrafluoroborate, and the electrolytes (h) do not contain any anion selected from the group consisting of acetate, formiate, citrate, oxalate, nitrate, difluorophosphate, hexafluorophosphate and tetrafluoroborate. Further preferably, a composition according to the present invention does not contain any anion selected from the group consisting of acetate, formiate, citrate, oxalate, nitrate, difluorophosphate, hexafluorophosphate and tetrafluoroborate. Preferably, said electrolytes (h) are selected from the group consisting of lithium aluminum chloride (LiAICU); lithium hexafluoroantimonate (LiSbFe); LiX(RS02)n wherein n=1 and X=0 n=2 and X=N, n=3 and X=C , and R in each case is CmH2m+i-nF_n wherein m = 0-20, n = 0- 21 , lithium perchlorate (LiCIC ); lithium tetrakis(pentafluorophenyl)borate; (LiPFe); lithium hexafluoroarsenate (LiAsFe); lithium bis(fluorosulfonyl)imide (LiN(S02F)2); lithium trifluoro- methylsulfonate (L1CF3SO3); LiN(S0₂C_nF2n₊i)2 wherein n = 2 to 20; LiC[(C_nF2n-i )S0₂]3 wherein n = 2 to 20; lithium bis(trifluoromethane)sulfonimide (LiN(CF3S02)2); and lithium tris-trifluoromethyl sulfonylmethide (LiC(CF3S02)3). Most preferably, said electrolyte (h) is selected from the group consisting of lithium perchlo- rate, lithium trifluoromethylsulfonate, lithium bis(trifluoromethane)sulfonimide and lithium bis(fluorosulfonyl)imide.

Preferably, in a composition according to the invention, the metal salt of formula (II) and the electrolyte (h) have the same anion.

Optionally, a composition according to the above-defined specific case further comprises

(i) electronically conductive nanoobjects not comprising any compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14. Said electronically conductive nanoobjects (i) form a dispersed phase, which is dispersed within the liquid external phase of the composition according to the present invention.

In a layer prepared from the above-defined composition, said electronically conductive nanoobjects deposited on a surface of a solid substrate may form a conductive network of adjacent and overlapping electronically conductive nanoobjects capable of carrying an electric current.

Preferably said electroconductive nanoobjects (i) have two external dimensions in the range of from 1 nm to 100 nm, and their third external dimension is in the range of from 1 μιη to 100 μιη, in each case determined by transmission electron microscopy. Typically, said two external dimensions which are in the range of from 1 nm to 100 nm are similar i.e. they differ in size by less than three times. The third dimension of said electroconductive nanoobjects is significantly larger, i.e. it differs from the other two external dimensions by more than three times. Preferably, said electroconductive nanoobjects (i) are nanowires as defined in ISO/TS 27687:2008 (as published in 2008) (for details, see above).

Preferably, the electronically conductive nanoobjects (i) are nanoobjects having a length in the range of from 1 μιη to 100 μιη, preferably of from 3 μιη to 50 μιη, more preferably of from 10 μιη to 50 μιη, and a diameter in the range of from 1 nm to 100 nm, preferably of from 2 nm to 50 nm, more preferably of from 15 nm to 30 nm, length and diameter in each case being determined by transmission electron microscopy.

Preferably, said electronically conductive nanoobjects are nanowires comprising materials selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel and alloys of two or more metals selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel. More preferably, said electronically conductive nanoobjects are nanowires consisting of materials selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel and alloys of two or more metals selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel.

Compositions according to the invention which comprise the above-defined constituents (h) and (i) are preferably obtained by a method following the teaching of non-prepublished patent application having the application number PCT/EP2017/055320. Basically said method comprises providing a first suspension comprising above-defined constituents (a),

(b) and (c), providing a second suspension comprising above-defined constituents (i) and

(c) , adding together said first suspension and said second suspension to obtain a third suspension comprising above-defined constituents (a), (b), (c), and (i), and admixing to said third suspension the above-defined constituents (d), (g), (h) and optionally (e) and (f).

A composition according to the present invention which contains the above-defined constituents (a), (b), (c), (d) and (g) and optionally one, more or all of the above-defined constituents (e), (f), (h) and (i) contains a single continuous liquid phase comprising the constituents (c) and (g) which at standard pressure 101 .325 kPa are liquid at temperatures below 120 °C and constituent (d) and - if present - constituent (e) and constituent (f) (if present in the form of soluble polymers) and constituent (h) which are dissolved in said liquid phase. Constituents (a) and - if present - constituent (i) and constituent (f) (if present in the form of polymer particles) each form a dispersed phase, which is dispersed within the liquid external phase.

A composition according to the present invention which contains the above-defined constituents (a), (b), (c), (d), (g) and (h) and optionally one, more or all of the above-defined constituents (e), (f), and (i) may be used for preparing an electrochromic composite layer which in an electrochromic device can function as an electrochromic electrode.

An electrochromic composite layer obtainable from a composition which contains the above-defined constituents (a), (b), (c), (d), (g), (h) and optionally one, more or all of the above-defined constituents (e), (f) and (i), comprises

a matrix formed of one or more organic polymers

and dispersed within said matrix

(a) nanoobjects comprising one or more electrochromic compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon

(b) one or more salts of formula (II) Μ³⁺(Ζ-) l;a (II)

wherein

M^a+ is a metal cation wherein a is 2, 3, 4 or 5, and

z- is a weakly coordinating anion whose corresponding acid has an acidity higher than the acidity of 100 % sulfuric acid,

(g) an aprotic organic liquid having a boiling point of 120 °C or higher,

(h) at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g).

Optionally, an electrochromic composite layer as defined above further comprises

(i) electronically conductive nanoobjects not comprising any compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 dispersed within said matrix formed of one or more organic polymers.

The term electrochromic composite layer denotes a layer comprising discrete nanoobjects (a) comprising one or more electrochromic compounds as defined above and constituents (g), (h) and optionally (i) dispersed within a continuous phase (matrix) extending throughout said layer. Both, an electronically conductive network and an ionically conductive network extend throughout the electrochromic composite layer providing for the transport of electrons and ions to and away from the dispersed nanoobjects comprising electrochromic compounds as defined above. Further constituents may be dispersed in the matrix, each fulfilling a specific function and interacting with the other constituents.

Within the electrochromic composite layer, the matrix provides mechanical integrity and stability and binds and accommodates the above-defined constituents of the electrochromic composite layer which are dispersed within said matrix. Without being bound to theory, it is believed that the nanoobjects (a) comprising one or more electrochromic compounds as defined above and - if present - the electronically conductive nanoobjects (i) as defined above, which are dispersed within the matrix, form a network extending throughout the electrochromic composite layer providing for the transport of electrons towards and away from the nanoobjects (a). Without being bound to theory, it is believed that in the electrochromic composite layer of the electrochromic device according to the present invention said aprotic organic liquid (g) including said dissolved electrolyte (h) as defined above is confined within pores extending through the matrix, thus providing a network for the transport of ions to and away from the nanoobjects (a) when an electric voltage is applied to the electrochromic device. Water may also provide for ionic conductivity of the electrochromic composite layer. An electrochromic composite layer comprising water is obtainable by using a carrier liquid (c) consisting of water and at least one other liquid having a boiling point of less than 120 °C. The amount of water that remains in said system consisting of water and two other liquids (said constituent of the carrier liquid having a boiling point of less than 120 °C and the aprotic organic liquid (g) having a boiling point of 120 °C or higher as defined above) can be estimated according to Raoult's law or can be determined from experimental data, as known by the skilled person. However, in the context of this disclosure, water is not an electrolyte (h) as defined above.

A composition according to the present invention which contains the above-defined constituents (a), (b), (c), (d) and (g) and optionally one, more or all of the above-defined constituents (e), (f), and (i) may be used for preparing a precursor layer of an electrochromic composite layer. A precursor layer of an electrochromic composite layer differs from an electrochromic composite layer as defined above in that said precursor layer does not contain any electrolytes (h). A precursor layer of an electrochromic composite layer may be transferred into an electrochromic composite layer by allowing migration or diffusion of ions of an electrolyte (h) as defined above from another source (see below) into said precursor layer.

Where appropriate, an electrochromic composite layer as defined above and a precursor layer thereof as defined above are herein commonly denoted as "a composite layer".

Thus, a composition according to the invention which may be used for preparing an electrochromic composite layer or a precursor layer thereof comprises

precursors (in the form of polymerizable moieties and optionally dissolved or suspended polymers) of the organic polymer matrix of the composite layer, and the above-defined constituents of the composite layer which are to be dispersed within said organic polymer matrix, and

a carrier liquid having a boiling point of less than 120 °C which does not become a constituent of the composite layer but merely acts as a vehicle for wet-processing.

Preferably, in a composition according to the present invention

(a) the amount of nanoobjects comprising one or more electrochromic compounds as defined above is in the range of from 0.1 wt.-% to 20 wt.-%, preferably 0.5 wt.-% to 10 wt.-%, (b) the amount of metal salt of formula (II) as defined above is in the range of from 0.001 wt.-% to 2 wt.-%, preferably 0.01 wt.-% to 1 wt.-%,

(c) the amount of the carrier liquid having a boiling point below 120 °C is in the range of from 70 wt.-% to 99.5 wt.-%, preferably 88 wt.-% to 99 wt.-%,

(d) the total amount of polymerizable moieties is in the range of from 0.005 wt.-% to 7.0 wt.-%, preferably 0.21 wt.-% to 2.5 wt.-%

(e) the total amount of initiators (if present) is in the range of from 0.00001 wt.-% to 0.06 wt.-%, preferably 0.0001 wt.-% to 0.05 wt.-%,

(f) the total amount of said polymers is in the range of from 0 wt.-% to 7.0 wt.-%, preferably 0.21 wt.-% to 2.5 wt.-%

(g) the amount of the aprotic organic liquid having a boiling point of 120 °C or higher is in the range of from 0.00009 wt.-% to 1 wt.-%, preferably 0.005 wt.-% to 0.7 wt.-%,

(h) the total amount of said electrolytes as defined above is in the range of from 0 wt.-% to 0.4 wt.-%, preferably 0 wt.-% to 0.08 wt.-%,

(i) the total amount of electronically conductive nanoobjects as defined above is in the range of from 0 wt.-% to 0.9 wt.-%, preferably 0 wt.-% to 0.4 wt.-%,

in each case based on the total weight of the composition.

When said polymerizable moieties are co-polymerizable monomers selected from the group consisting of alkyl acrylates and alkyl methacrylates and from the group consisting of hydroxyalkyi acrylates and hydroxyalkyi methacrylates, the total amount of monomers selected from the group consisting of alkyl acrylates and alkyl methacrylates is in the range of from 0.0004 wt.-% to 5.0 wt.-%, preferably 0.2 wt.-% to 2 wt.-%, and the total amount of monomers selected from the group of hydroxyalkyi acrylates and hydroxyalkyi methacrylates is in the range of from 0.0001 wt.-% to 2 wt.-%, preferably 0.01 wt.-% to 0.5 wt.-%.

Preferably, in said composition, the ratio between

(a) the total weight of said nanoobjects comprising one or more electrochromic compounds as defined above

and

(i) the total weight of said electronically conductive nanoobjects as defined above (if present)

is in the range of from 1 to 1000, preferably 5 to 300. At a weight ratio above 1000, in an electrochromic composite layer prepared from a composition according to the invention, the amount of electronically conductive nanoobjects (i) may be not sufficient to have a remarkable effect on the electronic conductivity. On the other hand, at a weight ratio below 1 , in an electrochromic composite layer prepared from a composition according to the invention the amount of nanoobjects (a) comprising one or more electrochromic compounds as defined above may be not sufficient for achieving an appropriate electrochromic effect.

Further preferably, the ratio between

(a) the total weight of said nanoobjects comprising one or more compounds as defined above

and

(h) the total weight of said electrolytes (if present)

is in the range of from 0.25 to 304200, preferably 6.25 to 7605.

At a weight ratio above 304200, in an electrochromic composite layer prepared from a composition according to the invention the amount of electrolytes (h) may be not sufficient for achieving an appropriate ionic conductivity. On the other hand, at a weight ratio below 0.25, in an electrochromic composite layer prepared from a composition according to the invention the amount of nanoobjects (a) comprising one or more electrochromic compounds as defined above may be not sufficient for achieving an appropriate electrochromic effect.

Further preferably, the ratio between

(g) the weight of said aprotic organic liquid having a boiling point of 120 °C or higher and

(h) the total weight of said electrolytes (if present)

is in the range of from 0.0002 to 104000, preferably 0.06 to 100.

At a weight ratio below 0.0002, the amount of the aprotic organic liquid (g) in an electrochromic composite layer prepared from a composition according to the invention may be not sufficient for dissolving the electrolytes (h). On the other hand, at a weight ratio above 104000, the amount of electrolytes (h) in an electrochromic composite layer prepared from a composition according to the invention may be not sufficient to achieve an appropriate ionic conductivity if there is no migration or diffusion of ions of an electrolyte (h) as defined above from another source into said layer. Further preferably, the ratio between

(d) the total weight of said polymerizable moieties

and the total weight of

(a) said nanoobjects comprising one or more electrochromic compounds as defined above

(g) said aprotic organic liquid having a boiling point of 120 °C or higher

(h) said electrolytes (if present)

(i) said electronically conductive nanoobjects as defied above (if present)

is in the range of from 0.00002 to 70, preferably 0.019 to 4.95.

At a weight ratio below 0.00002, the amount of polymerizable moieties in the composition may be not sufficient for forming a matrix which is capable of binding and accommodating the constituents (a), (g), (h) and (i) as described above when an electrochromic composite layer is prepared from a composition according to the invention. On the other hand, at a weight ratio above 70, the amount of the constituents (a), (g), (h) and (i), which determine the electrochromic effect and other important properties of an electrochromic composite layer prepared from a composition according to the present invention may be not sufficient to achieve the desired properties.

Further preferably the ratio between

(a) the total weight of nanoobjects comprising one or more electrochromic compounds as defined above

and

(c) the weight of said carrier liquid having a boiling point below 120 °C

is in the range of from 0.001 to 0.286, preferably 0.005 to 0.1 14.

At a weight ratio above 0.286, the fraction of solids in the composition is quite high, which may impede application of the composition by means of wet processing techniques. On the other hand, at a weight ratio below 0.001 , the fraction of the carrier liquid, which has to be removed in the process of forming an electrochromic composite layer, is relatively large, and processing may become inefficient.

In a specifically preferred composition according to the present invention,

(a) said nanoobjects are nanoparticles comprising one or more oxides of nickel, preferably consisting of one or more oxides of nickel (b) said metal salts of formula (II) are selected from the group consisting of scandium bis(trifluoromethane)sulfonimide, yttrium bis(trifluoromethane)sulfonimide, aluminum bis(trifluoromethane)sulfonimide, lanthanum bis(trifluoromethane)sulfonimide, cerium bis(trifluoromethane)sulfonimide, nickel bis(fluorosulfonyl)imide, copper bis(fluorosulfonyl)imide, zinc bis(fluorosulfonyl)imide, yttrium trifluoromethyl- sulfonate, aluminum trifluoromethylsulfonate, lanthanum trifluoromethylsulfonate, cerium trifluoromethylsulfonate, and yttrium fluorosulfonate

(c) said carrier liquid is selected from the group consisting of ethanol, methanol, 2-pro- panol, 2-methyl tetrahydrofuran and mixtures thereof,

and said composition further comprises

(d) one or more kinds of monomers selected from the group consisting of alkyl acrylates and alkyl methacrylates and one or more kinds of monomers selected from the group consisting of hydroxyalkyl acrylates and hydroxyalkyl methacrylates

(e) optionally one or more initiators for initiating radical polymerization of said co- polymerizable monomers (d)

(g) an aprotic organic liquid selected from the group consisting of ethylene carbonate, fluorinated ethylene carbonate, 1 ,2-propylene carbonate, fluorinated 1 ,2-propylene carbonate, 1 ,3-propylene carbonate, fluorinated 1 ,3-propylene carbonate and mixtures thereof

(h) optionally at least one electrolyte selected from the group consisting of lithium per- chlorate, lithium trifluoromethylsulfonate, lithium bis(trifluoromethane)sulfonimide and lithium bis(fluorosulfonyl)imide

(i) optionally nanowires comprising, preferably consisting of materials selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel and alloys of two or more metals selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel, preferably silver nanowires.

Preferably said polymerizable monomers are butyl acrylate and hydroxybutyl acrylate.

For preferred concentration ranges and weight ratios of the constituents of the above-described specifically preferred composition according to the present invention, reference is made to the disclosure provided above. A second aspect of the present invention relates to a process for preparing a layer comprising

(a) nanoobjects comprising one or more compounds selected from the group consisting of

- oxides, sulfides, selenides, and tellurides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon

and

compounds of formula (I)

wherein A is a monovalent organic cation or an alkali metal cation, D is Pb, Sn, or Ge,

X is CI, Br, or I,

i is an integer from 0 to 6, wherein preferably i = 0

(b) one or more salts of formula (II)

M^a+(Z )a (II)

wherein

M^a+ is a metal cation wherein a is 2, 3, 4 or 5, and

on a surface of a solid substrate,

said process comprising the steps of

forming on a surface of said solid substrate a wet film by applying a composition according to the first aspect of the present invention to said surface of said solid substrate

removing said carrier liquid (c) from the wet film formed on said surface of said solid substrate.

In certain cases, after removal of the carrier liquid from the surface of said solid substrate is completed, a sequence comprising the steps of

- forming a wet film by applying the above-defined composition according to the invention to the surface of the layer formed on the surface of the substrate after removal of the carrier liquid, removing said carrier liquid from said wet film,

is carried out and optionally repeated at least once.

Said solid substrate comprises, preferably consists of, one or more materials selected from the group consisting of glasses, metals, transparent conducting oxides and organic polymers.

In some cases, the surface of the solid substrate to which the composition according to the invention is applied comprises an electronically conductive material, preferably an optically transparent electronically conductive material. Preferred optically transparent conducting materials are transparent conducting oxides (TCO), preferably selected from the group consisting of ITO (indium doped tin oxide), AZO (aluminum doped zinc oxide), IGZO (indium gallium doped zinc oxide), GZO (gallium doped zinc oxide), FTO (fluorine doped tin oxide), indium oxide, tin oxide and zinc oxide. In some cases, the surface of the solid substrate layer upon which the electrochromic composite layer is arranged comprises one or more metallic electronically conductive materials, wherein the metals are preferably selected from the group consisting of Cu, Ag, Au, Pt and Pd. Preferably, the metal at the solid substrate surface is present in the form of a structure which is optically transparent, e.g. in the form of fine mesh or nanowires.

However, it has been found that in cases where the composition comprises electroconduc- tive nanoobjects (i) as defined above the electronic in-plane conductivity of an electrochromic composite layer prepared from a composition according to the invention is sufficiently high so that providing the solid substrate surface with an electronically conductive material can be omitted.

Said solid substrate is preferably in a form selected from the group consisting of foils, films, webs, panes and plates.

In certain cases, said solid substrate comprises an organic polymer and has a thickness in the range of from 10 μιη to 200 μιη, preferably from 50 μιη to 150 μιη.

In other cases, said solid substrate comprises glass and has a thickness in the range from 3 to 7 mm, preferably 4 to 6 mm, or in the range from 0.5 to 2.5 mm, preferably 0.7 to 2 mm. Preferred types of glass are e.g. float glass, low iron float glass, heat strengthened glass and chemically strengthened glass. Optionally, the glass has a low-emissivity (low-e) coating, sun-protection coating or any other coating on the surface facing away from the above- described composite layer. Preferred organic polymers are selected from the group consisting of polymethylmethacrylate (PMMA, commercially available e.g. as Plexiglas™), polycarbonate (PC), polyethylene (PE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), polypropylene (PP), low density polypropylene (LDPP), polyethylene therephthalate (PET), glycol modified polyethylene therephthalate, polyethylene naphthalate (PEN), cellulose acetate butyrate, polylactide (PL), polystyrene (PS), polyvinyl chloride (PVC), polyimides (PI), pol- ypropyleneoxide (PPO) and mixtures thereof. PET and PEN are particularly preferred.

Preferably, said solid substrate has a light transmission of 80 % or more measured according to ASTM D1003 (Procedure A) as published in November 2013.

Preferably, the composition according to the present invention is applied to the surface of said solid substrate by coating or printing, preferably by a coating technique selected from the group consisting of roll-to-roll-, roll-to-sheet-, sheet-to-sheet-, slot-die-, spray-, ultrasonic spray-, dip- and blade coating, or by a printing technique selected from the group consisting of ink-jet-, pad-, offset-, gravure-, screen-, intaglio- and sheet-to-sheet- printing.

Preferably, the wet film formed by applying the composition according to the present inven- tion to said surface of said solid substrate has a thickness in a range of from 1 μιη to 250 μιη, preferably of from 20 μιη to 150 μιη. Said thickness is also referred to as "wet thickness".

In the above-defined process according to the present invention, preferably the carrier liquid has a boiling point below 120 °C and is removed from said wet film on said surface of said solid substrate by exposing said wet film to a temperature in the range of from 20 °C to 120 °C, preferably 40 °C to 120 °C, most preferably 80 °C to 120 °C.

Preferably, the composition which in the process according to the invention is applied to said surface of said solid substrate is selected from the above-defined preferred compositions according to the first aspect of the present invention. In a preferred process according to the present invention said composition applied to said surface of said solid substrate comprises

(c) a carrier liquid having a boiling point of less than 120 °C, and

(d) one or more polymerizable moieties,

and said process further comprises the step of

polymerizing the polymerizable moieties on said surface of said solid substrate. Particularly preferably, the composition applied to said surface of said solid substrate comprises

(d) one or more polymerizable moieties,

and

(e) one or more initiators for initiating radical polymerization of said polymerizable moi- eties.

Polymerization of the polymerizable moieties is preferably initiated by irradiation, especially irradiation having a wavelength in the range of from 360 nm to 420 nm, in the presence of an initiator which decomposes into radicals when exposed to said irradiation. Suitable initiators are known in the art and are commercially available. In certain cases, preparing said process further comprises the step of annealing the layer formed on the surface of the solid substrate after polymerizing the polymerizable monomers.

The step of polymerizing the polymerizable moieties on said surface of said solid substrate is performed after the step of removing said carrier liquid having a boiling point below 120 °C from the wet film formed on said surface of said solid substrate. In certain cases, in the step of polymerizing the polymerizable moieties the degree of conversation of the double bonds in the polymerizable moieties is significantly below 96 %, preferably 90 % or less, further preferably 80 % or less, more preferably 70 % or less, particularly preferably 60 % or less, or 50 % or less, and polymerization is completed in a later stage e.g. when the surface of the composite layer facing away from the solid substrate is to be bonded to another layer (see below).

In certain cases, after polymerization of said polymerizable moieties on the surface of said solid substrate, a sequence comprising the steps of

forming a wet film by applying the above-defined composition according to the in- vention on the surface of the layer wherein the polymerizable moieties have been polymerized, removing from said wet film said carrier liquid (c)

polymerizing said polymerizable moieties in the layer,

optionally annealing the layer after polymerizing the polymerizable monomers is carried out and optionally repeated at least once.

An especially preferred process according to the second aspect of the present invention is a process for preparing a precursor layer of an electrochromic composite layer as defined above on a surface of a solid substrate, said process comprising the steps of

forming on a surface of said solid substrate a wet film by applying a composition which contains the above-defined constituents (a), (b), (c), (d) and (g) and optionally one, more or all of the above-defined constituents (e), (f) and (i) to said surface of said solid substrate

removing said carrier liquid (c) from the wet film formed on said surface of said solid substrate

polymerizing the polymerizable moieties (d) on said surface of said solid substrate.

Another especially preferred process according to the second aspect of the present invention is a process for preparing an electrochromic composite layer as defined above on a surface of a solid substrate, said process comprising the steps of

forming on a surface of said solid substrate a wet film by applying a composition which contains the above-defined constituents (a), (b), (c), (d), (g) and (h) and optionally one, more or all of the above-defined constituents (e), (f) and (i) to said surface of said solid substrate

Preferably, in a process for preparing a composite layer as defined above, the following constituents of the composition according to the first aspect of the present invention are applied to the surface of said solid substrate in the following amount per cm² of said surface:

(a) nanoobjects comprising one or more electrochromic compounds as defined above in an amount of 0.10 mg/cm² to 6 mg/cm²

(d) polymerizable moieties in an amount of 0.0007 mg/cm² to 13.3 mg/cm²

(f) optionally polymers in an amount of 0.0007 mg/cm² to 13.3 mg/cm² (g) the aprotic organic liquid having a boiling point of 120 °C or higher in an amount of 0.0001 mg/cm² to 2.05 mg/cm²

(h) optionally electrolytes having cations selected from the group consisting of H⁺, Li⁺, Na⁺, K⁺ in an amount of 0.00002 mg/cm² to 0.32 mg/cm²

(i) optionally electronically conductive nanoobjects not comprising any oxides of nickel in an amount of 0.0009 mg/cm² to 6 mg/cm².

When said polymerizable moieties are co-polymerizable monomers selected from the group consisting of alkyi acrylates and alkyi methacrylates and from the group consisting of hydroxyalkyl acrylates and hydroxyalkyl methacrylates, said monomers selected from the group consisting of alkyi acrylates and alkyi methacrylates are applied in an amount of 0.0006 mg/cm² to 10.9 mg/cm² and said monomers selected from the group of hydroxyalkyl acrylates and hydroxyalkyl methacrylates in an amount of 0.0001 mg cm² to 2.4 mg /cm².

A third aspect of the present invention relates to the use of a composition according to the first aspect of the present invention for preparing a layer comprising

and

compounds of formula (I)

X is CI, Br, or I,

i is an integer from 0 to 6, wherein preferably i = 0

(b) one or more salts of formula (II)

M^a+(Z )a (II)

wherein

M^a+ is a metal cation wherein a is 2, 3, 4 or 5, and

Z^" is a weakly coordinating anion whose corresponding acid has an acidity higher than the acidity of 100 % sulfuric acid. on a surface of a solid substrate.

Preferably, the composition used herein is selected from the above-defined preferred compositions according to the first aspect of the present invention.

It is noted that a composition according to the first aspect of the present invention may also be used for preparing any other objects and formulations comprising nanoobjects (a) as defined above.

A fourth aspect of the present invention relates to an article comprising

a solid substrate having a surface

and, arranged on said surface of said solid substrate, a layer comprising

and

compounds of formula (I)

A_{1 +i} DX_3+i (I)

X is CI, Br, or I,

i is an integer from 0 to 6, wherein preferably i = 0

(b) one or more salts of formula (II)

M^a+(Z )a (II)

wherein

M^a+ is a metal cation wherein a is 2, 3, 4 or 5, and

Z^" is a weakly coordinating anion whose corresponding acid has an acidity higher than the acidity of 100 % sulfuric acid.

Preferably, said solid substrate comprises one or more materials selected from the group consisting of glasses, metals, transparent conducting oxides and organic polymers. Said solid substrate is preferably in a form selected from the group consisting of foils, films, webs, panes and plates. Preferably said solid substrate is optically transparent, i.e. exhibits a light transmission of 80 % or more measured according to DIN EN 410. Regarding further specific and preferred features of the solid substrate, reference is made to the disclosure provided above in the context of the second aspect of the present invention.

The above-defined layer is arranged on a surface of said solid substrate in such manner that it partially or completely covers a surface of said solid substrate. In specific cases the layer forms a pattern on said surface of said solid substrate. The pattern may be selected from any random and non-random structures, like grids, stripes, waves, dots and circles.

The above-defined layer arranged on the surface of the solid substrate has a thickness in the range of from 0.05 μιη to 500 μιη, preferably 0.05 μιη to 50 μιη, most preferably 0.1 μιη to 30 μιη.

Preferably, in said article according to the present invention, said layer arranged on said surface is an electrochromic composite layer or a precursor layer thereof as defined above. Where appropriate, an electrochromic composite layer as defined above and a precursor layer thereof as defined above are herein commonly denoted as "a composite layer". Preferably, the constituents of the composite layer are selected from the above-defined preferred ones described above in the context of the first aspect of the present invention.

In a preferred article according to the invention said composite layer comprises

a matrix formed of one or more organic polymers which are copolymerization products of one or more monomers selected from the group consisting of alkyl acrylates and alkyl methacrylates and one or more monomers selected from the group of hy- droxyalkyl acrylates and hydroxyalkyl methacrylates

and dispersed within said matrix

(a) nanoparticles comprising one or more oxides of nickel, preferably consisting of one or more oxides of nickel,

(b) one or more salts of formula (II) selected from the group consisting of scandium bis(trifluoromethane)sulfonimide, yttrium bis(trifluoromethane)sul- fonimide, aluminum bis(trifluoromethane)sulfonimide, lanthanum bis(trifluoro- methane)sulfonimide, cerium bis(trifluoromethane)sulfonimide, nickel bis(fluorosulfonyl)imide, copper bis(fluorosulfonyl)imide, zinc bis(fluorosul- fonyl)imide, yttrium trifluoromethylsulfonate, aluminum trifluoromethyl- sulfonate, lanthanum trifluoromethylsulfonate, cerium trifluoromethylsulfonate, and yttrium fluorosulfonate (g) an aprotic organic liquid selected from the group consisting of ethylene carbonate, fluorinated ethylene carbonate, 1 ,2-propylene carbonate, fluorinated 1 ,2-propylene carbonate, 1 ,3-propylene carbonate, fluorinated 1 ,3-propylene carbonate and mixtures thereof

(h) optionally at least one electrolyte selected from the group consisting of lithium perchlorate, lithium trifluoromethylsulfonate, lithium bis(trifluoromethane)sul- fonimide and lithium bis(fluorosulfonyl)imide dissolved in said aprotic organic liquid (g).

In certain cases, said composite layer further comprises

(i) nanowires comprising, preferably consisting of, materials selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel and alloys of two or more metals selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel

dispersed within said matrix formed of one or more organic polymers which are copolymer- ization products of one or more monomers selected from the group consisting of alkyl acry- lates and alkyl methacrylates and one or more monomers selected from the group of hy- droxyalkyl acrylates and hydroxyalkyl methacrylates.

If any electrolytes (h) as defined above are present in said composite layer, it is an electro- chromic composite layer as defined above. If no electrolytes (h) as defined above are pre- sent in said composite layer, it is a precursor layer as defined above.

In certain cases, an article according to the fourth aspect of the present invention consists of the above-defined solid substrate and the above-defined layer arranged on a surface of said solid substrate.

In other cases, an article according to the fourth aspect of the present invention contains further layers which may serve specific functions.

A specifically preferred article according to the fourth aspect of the present invention comprises a multilayer structure suitable for production of or use in an electrochromic device. The term "electrochromic device" as used herein refers to a device exploiting the electrochromic effect as defined above. Such device comprises at least one electrode comprising an electrochromic material, a counter electrode and a separator layer sandwiched between and electronically separating said electrodes. Electrochromic devices are used, inter alia, as fagade and roof elements, interior construction and design elements for buildings and vehicles, displays, visualization optics and electrochromic mirrors. A widely known type of electrochromic devices are so-called smart windows. The term "smart windows" is known in the art.

Such preferred article for production of or use in an electrochromic device comprises a first solid substrate having a surface

- arranged on said surface of said first solid substrate, a composite layer as defined above

a separator layer disposed on the surface of the composite layer facing away from the solid substrate.

Such preferred article is obtainable by a process comprising the steps of

- preparing a composite layer as defined above on a surface of a solid substrate by a process as described above in the context of the second aspect of the present invention, and

disposing a separator layer on the surface of said composite layer facing away from the solid substrate. Said separator layer is virtually electronically insulating, but allows for flow of ions. For further details, see below.

Another preferred article for production of or use in an electrochromic device comprises a first solid substrate having a surface

arranged on said surface of said first solid substrate, a composite layer as defined above

a second solid substrate having a surface

arranged on said surface of said second solid substrate, a counter electrode layer a separator layer sandwiched between and electronically separating said composite layer and said counter electrode layer. Said article comprises a multilayer structure which in the direction of stacking consists of a first solid substrate, a composite layer as defined above, a separator layer, a counter electrode layer and a second solid substrate.

In said article, said separator layer has a first surface and a second surface opposite to said first surface, wherein said first surface of said separator layer is in contact with a sur- face of said composite layer facing away from said first solid substrate, and said second surface of said separator layer is in contact with a surface of said counter electrode layer facing away from said second solid substrate.

Said separator layer is virtually electronically insulating and electronically separates the composite layer and the counter electrode but allows for flow of ions between the composite layer and the counter electrode. Suitable separator layers are known in the art.

Said separator layer preferably has a thickness in the range of from 0.05 μιη to 1500 μιη, preferably 0.05 μιη to 1000 μιη, most preferably 1 μιη to 800 μιη. Thickness may be determined by profilometry, atomic force microscopy or electron microscopy.

Preferably, in said article for production of or use in an electrochromic device at least one of said solid substrates has a light transmission of 80 % or more measured according to DIN EN 410.

An article comprising the above-defined multilayer structure is obtainable by a process comprising the steps of

preparing

- a first layer assembly comprising a first solid substrate having a surface and arranged on said surface of said first solid substrate a composite layer as defined above, and optionally a separator layer disposed on a surface of said composite layer facing away from said first solid substrate or a wet film obtained by applying a composition suitable for forming a separator layer on said surface of the first composite layer facing away from said first solid substrate, and

a second layer assembly comprising a second solid substrate having a surface and arranged on said surface of said second solid substrate a counter electrode layer, and optionally a separator layer disposed on a surface of said counter electrode layer facing away from said second solid substrate or a wet film obtained by applying a composition suitable for forming a separator layer on said surface of the counter electrode layer facing away from said second solid substrate,

with the proviso that at least one of said first and second layer assembly comprises a separator layer or a wet film as defined above

stacking and bonding said layer assemblies so that an article is obtained having a separator layer sandwiched between said first composite layer and said counter electrode layer. Preferably, in said article for production of or use in an electrochromic device, said separator layer comprises

a matrix formed of one or more organic polymers

and dispersed within said matrix

(g") an aprotic organic liquid having a boiling point of 120 °C or higher,

(h") optionally at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g").

Accordingly, disposing a separator layer on the surface of said composite layer facing away from said first solid substrate and/or on the surface of said counter electrode layer facing away from said second solid substrate comprises the steps of

forming on said surface of said composite layer resp. said counter electrode layer a wet film by applying to said surface a composition comprising

(c") optionally a carrier liquid having a boiling point below 120 °C

(d") one or more kinds of polymerizable moieties,

(e") optionally one or more initiators for initiating radical polymerization of said one or more kinds of polymerizable moieties

(g") an aprotic organic liquid having a boiling point of 120 °C or higher

(h") optionally at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺

in case the composition contains a carrier liquid (c") having a boiling point below 120 °C, removing the carrier liquid having a boiling point below 120 °C from the wet film formed on the surface of said composite layer resp. said counter electrode layer polymerizing the polymerizable moieties in the layer formed on the surface of said composite layer resp. said counter electrode layer.

In certain cases, said composition for preparing the separator layer comprises a carrier liquid. However, in said composition for disposing a separator layer as defined above advantageously a carrier liquid as a vehicle for wet processing can be omitted, because said composition does not comprise non-dissolved matter, in contrast to the above-described composition for preparing an electrochromic composite layer or a precursor layer thereof. Accordingly, the step of removing the carrier liquid from the wet film can be omitted in preparing the separator layer. Regarding preferred and specific carrier liquids (c"), polymerizable moieties (d"), initiators (e"), aprotic organic liquids (g") having a boiling point of 120 °C or higher and electrolytes (h"), the same applies as disclosed above in the context of the first aspect of the present invention for the carrier liquid (c), polymerizable moieties (d), initiators (e), aprotic organic liquid (g) having a boiling point of 120 °C or higher and electrolytes (h), resp., of the composition according to the first aspect of the present invention.

In the composition for preparing the separator layer, preferably the polymerizable moieties (d") are the same as the polymerizable moieties (d) in the composition for preparing the composite layer, the aprotic organic liquid (g") having a boiling point of 120 °C or higher is the same as the aprotic organic liquid (g) in the composition for preparing the composite layer, and - if present - the electrolyte (h") is the same as the electrolyte (h) in the composition for preparing the composite layer.

Accordingly, in said separator layer, preferably the matrix is formed of the same organic polymers as the matrix in the first composite layer, the aprotic organic liquid (g") having a boiling point of 120 °C or higher is the same as the aprotic organic liquid (g) in the first composite layer and - if present - the electrolyte (h") is the same as the electrolyte (h) in the first composite layer.

Without being bound to theory, it is believed that in the separator layer of the electrochromic device according to the present invention said aprotic organic liquid (g") including said dis- solved electrolytes (h") as defined above is confined within pores extending through the matrix, thus providing a network for the transport of ions across the separator layer.

Water may also provide for ionic conductivity of the separator layer. A separator layer comprising water is obtainable by using a carrier liquid (c") consisting of water and another liquid having a boiling point of less than 120 °C. The amount of water that remains in said system consisting of water and two other liquids (said constituent of the carrier liquid having a boiling point of less than 120 °C and the aprotic organic liquid (g") having a boiling point of 120 °C or higher as defined above) can be estimated according to Raoult's law or can be determined from experimental data, as known by the skilled person. However, in the context of this disclosure, water is not an electrolyte (h") as defined above. If said composition for preparing the separator layer comprises a carrier liquid, the step of polymerizing the polymerizable moieties is performed after the step of removing said carrier liquid having a boiling point below 120 °C from the wet film formed on said surface of said solid substrate. In certain cases, in the step of polymerizing the polymerizable moie- ties the degree of conversation of the double bonds in the polymerizable moieties is significantly below 96 %, preferably 90 % or less, further preferably 80 % or less, more preferably 70 % or less, particularly preferably 60 % or less, or 50 % or less, and polymerization is completed in a later stage e.g. for bonding the surface of the separator layer facing away from the composite layer to another layer (see below).

In certain cases, after polymerization of said polymerizable moieties on the surface of said composite layer, a sequence comprising the steps of

forming a wet film by applying the above-defined composition on the surface of the layer wherein the polymerizable moieties have been polymerized,

in case the composition contains a carrier liquid (c"), removing from said wet film said carrier liquid having a boiling point below 120 °C,

polymerizing said polymerizable moieties in the layer,

is carried out and optionally repeated at least once.

Preferably, the composition for preparing the separator layer is applied to the surface of said composite layer by coating or printing, preferably by a coating technique selected from the group consisting of roll-to-roll-, roll-to-sheet-, sheet-to-sheet-, slot-die-, spray-, ultrasonic spray-, dip- and blade coating, or by a printing technique selected from the group consisting of ink-jet-, pad-, offset-, gravure-, screen-, intaglio- and sheet-to-sheet- printing.

In the above-defined process for disposing the separator layer, the carrier liquid (c") - if present - is removed from said wet film on said surface of said solid substrate by exposing said wet film to a temperature in the range of from 20 °C to 120 °C, preferably 40 °C to 120 °C, most preferably 80 °C to 120 °C.

Preferably, the composition for preparing the separator layer does not contain a carrier liquid (c"), and the wet film formed by applying the composition for preparing the separator layer to said surface of said composite layer has a thickness in a range of from 0.05 μιη to 1500 μιη, preferably of from 0.05 μιη to 1000 μιη. Said thickness is also referred to as "wet thickness".

For further details of disposing a separator layer on the surface of said composite layer facing away from said first solid substrate and/or on the surface of said counter electrode layer facing away from said second solid substrate, see the non-prepublished patent application having the application number PCT/EP2017/055320. Said counter electrode layer comprises an electroactive material capable of repeatedly inserting and releasing ions to compensate for changes of the oxidation state of the metal of the electrochromic metal oxide in the nanoobjects (a) present in the electrochromic composite layer. Upon operation of the electrochromic device the electrochromic composite layer and the counter electrode layer are connected to a direct voltage source. Between the electrochromic composite layer and the counter electrode, virtually no electrons are transferred across the separator layer.

Said counter electrode layer may comprise an electroactive material which independent from its state of oxidation is substantially optically transparent or has an electrochromic effect involving a color change significantly less pronounced than that of the electrochromic metal oxide in the nanoobjects (a) of the electrochromic composite layer. Suitable electroactive materials are known in the art and include, but are not limited to tin oxide, cerium oxide, and transparent polymers capable of intercalating lithium ions.

Alternatively, said counter electrode layer comprises an electroactive material which exhib- its an electrochromic effect having a dependence on the applied electrochemical potential which is opposite to the electrochromic effect of the electrochromic metal oxide in the electrochromic composite layer. For instance, the electrochromic oxide of the electrochromic composite layer colors during anodic oxidation and discolors during cathodic reduction, and the electrochromic material in the counter electrode colors during cathodic reduction and discolors during anodic oxidation, or vice versa. Alternatively, the electrochromic oxide of the electrochromic composite layer adopts a dark color during anodic oxidation and a less dark color during cathodic reduction, and the electrochromic material in the counter electrode adopts a dark color during cathodic reduction and a less dark color during anodic oxidation, or vice versa. For instance, the counter electrode layer is obtained by depositing an electroactive material on the surface of said second solid substrate. Depositing the electroactive material (e.g. an electrochromic material) may be achieved by means of sputtering.

In case the counter electrode does not contain any electrolyte, at least one of the composition according to the first aspect of the present invention (which is used for preparing the composite layer) and the composition for preparing the separator layer must contain an electrolyte (h), (h"), resp.

Preferably, in said article for production of or use in an electrochromic device, said counter electrode layer is a second composite layer comprising

a matrix formed of one or more organic polymers and dispersed within said matrix

(a') nanoobjects comprising one or more electrochromic compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon which are different from the electro- chromic compounds comprised by the nanoobjects (a) of the first composite layer

(b') optionally one or more salts of formula (II)

M^a+(Z )a (II)

wherein

M^a+ is a metal cation wherein a is 2, 3, 4 or 5, and

(g') an aprotic organic liquid having a boiling point of 120 °C or higher,

(h') optionally at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g').

In certain cases, said second composite layer further comprises

(i') electronically conductive nanoobjects not comprising any compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 dispersed within said matrix formed of one or more organic polymers.

Preferably, said electroconductive nanoobjects (i') are nanowires comprising, preferably consisting of, materials selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel and alloys of two or more metals selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel.

Accordingly, said article comprises a first composite layer arranged on a surface of said first solid substrate, and a second composite layer arranged on a surface of said second solid substrate. Said article comprises a multilayer structure which in the direction of stacking consists of a first solid substrate, a first composite layer as defined above, a separator layer, a second composite layer as defined above and a second solid substrate. In said article said separator layer has a first surface and a second surface opposite to said first surface, wherein said first surface of said separator layer is in contact with a surface of said first composite layer facing away from said first solid substrate, and said second surface of said separator layer is in contact with a surface of said second composite layer facing away from said second solid substrate.

In said second composite layer, the nanoobjects (a') comprise electrochromic compounds which are different from the electrochromic compounds comprised by the nanoobjects (a) of the first composite layer. As regards criteria for selecting said electrochromic material, see above. In a specific preferred case, the nanoobjects (a) of the first composite layer comprise one or more oxides of nickel, and the nanoobjects (a') of the second composite layer comprise one or more oxides of tungsten.

In said second composite layer, preferably the matrix is formed of the same organic poly- mers as the matrix in the first composite layer, the aprotic organic liquid (g') having a boiling point of 120 °C or higher is the same as the aprotic organic liquid (g) in the first composite layer, and - if present - the electrolyte (h') is the same as the electrolyte (h) in the first composite layer.

Such preferred article for production of or use in an electrochromic device is obtainable by a process comprising the steps of

preparing

a first layer assembly comprising a first solid substrate having a surface and arranged on said surface of said first solid substrate a first composite layer as defined above, and optionally a separator layer disposed on a surface of said first composite layer facing away from said first solid substrate or a wet film obtained by applying the above-described composition for forming a separator layer on said surface of the first composite layer facing away from said first solid substrate,

and

- a second layer assembly comprising a second solid substrate having a surface and arranged on said surface of said second solid substrate a second composite layer as defined above, and optionally a separator layer disposed on a surface of said second composite layer facing away from said second solid substrate or a wet film obtained by applying the above-defined composi- tion for forming a separator layer on said surface of the second composite layer facing away from said second solid substrate,

with the proviso that at least one of said first and second layer assembly comprises a separator layer or a wet film as defined above stacking and bonding said layer assemblies so that an article is obtained having a separator layer sandwiched between said first composite layer and said second composite layer.

In this process, a bonding is achieved between the separator layer of the first layer assembly and the second composite layer, resp. between the separator layer of the second layer assembly and the first composite layer, resp. between the separator layer of the first layer assembly and the separator layer of the second layer assembly. For further details, see the non-prepublished patent application having the application number PCT/EP2017/055320.

Bonding may be achieved by polymerizing the monomers (d") in said wet film obtained by applying the above-defined composition for preparing a separator layer on the surface of the first resp. second composite layer as defined above, or by completing the polymerization of the polymerizable moieties (d), (d'), (d"), resp. in said layers to be bonded.

More preferably, in said article for production of or use in an electrochromic device, said counter electrode layer is a second composite layer as defined above

and said separator layer comprises

a matrix formed of one or more organic polymers

and dispersed within said matrix

(g") an aprotic organic liquid having a boiling point of 120 °C or higher,

Disposing a separator layer on the surface of said first composite layer facing away from said first solid substrate and/or on the surface of said second composite layer facing away from said second solid substrate comprises the steps as described above.

In said second composite layer and said separator layer, preferably the matrix is formed of the same organic polymers as the matrix in the first composite layer, the aprotic organic liquid (g') resp. (g") having a boiling point of 120 °C or higher is the same as the aprotic organic liquid (g) in the first composite layer, and - if present - the electrolyte (h') resp. (h") is the same as the electrolyte (h) in the first composite layer.

Accordingly, in the composition for preparing the second composite layer and in the composition for preparing the separator layer, preferably the polymerizable moieties (d') resp. (d") are the same as the polymerizable moieties (d) in the composition for preparing the first composite layer, the aprotic organic liquid (g') resp. (g") having a boiling point of 120 °C or higher is the same as the aprotic organic liquid (g) in the composition for preparing the first composite layer, and - if present - the electrolyte (h') resp. (h") is the same as the electrolyte (h) in the composition for preparing the first composite layer.

It is noted that in an article for production of or use in an electrochromic device comprising a first composite layer as defined above and one or both of a separator layer as defined above and a second composite layer as defined above, at least one of said layers must contain an electrolyte (h), (h'), (h"), resp. It has been found that ions from the electrolyte which is present in one of said layers may enter the other layer(s) by diffusion and migration, thereby providing for sufficient ionic conductivity across the respective layers.

Accordingly, at least one of the composition according to the first aspect of the present invention (which is used for preparing the first composite layer), the composition for preparing the separator layer and the composition for preparing the second composite layer must contain an electrolyte (h), (h'), (h"), resp.

Water may also provide for ionic conductivity of the composite layers and the separator layer, as explained above. However, in the context of this disclosure, water is not an electrolyte (h), (h'), (h") as defined above. A specifically preferred article for production of or use in an electrochromic device comprises

a first solid substrate having a surface

arranged on said surface of said first solid substrate, a first composite layer a second solid substrate having a surface

arranged on said surface of said second solid substrate, a second composite layer a separator layer interfacing and electronically separating said first composite layer and said second composite layer.

wherein

said first composite layer comprises

a matrix formed of one or more organic polymers

and dispersed within said matrix

(a) nanoobjects comprising one or more electrochromic oxides of nickel

(b) one or more salts of formula (II) as defined above

(g) an aprotic organic liquid having a boiling point of 120 °C or higher, (h) optionally at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g) and

said second composite layer comprises

(a') nanoobjects comprising one or more electrochromic oxides of tungsten

(g') an aprotic organic liquid having a boiling point of 120 °C or higher,

Further preferably, in said specifically preferred article for production of or use in an electrochromic device said first composite layer comprises

and dispersed within said matrix

(a) nanoparticles comprising one or more oxides of nickel

(b) one or more salts of formula (II) selected from the group consisting of scandium bis(trifluoromethane)sulfonimide, yttrium bis(trifluoromethane)sul- fonimide, aluminum bis(trifluoromethane)sulfonimide, lanthanum bis(trifluoro- methane)sulfonimide, cerium bis(trifluoromethane)sulfonimide, nickel bis(fluorosulfonyl)imide, copper bis(fluorosulfonyl)imide, zinc bis(fluorosul- fonyl)imide, yttrium trifluoromethylsulfonate, aluminum trifluoromethyl- sulfonate, lanthanum trifluoromethylsulfonate, cerium trifluoromethylsulfonate, and yttrium fluorosulfonate

(h) optionally at least one electrolyte selected from the group consisting of lithium perchlorate, lithium trifluoromethylsulfonate, lithium bis(trifluoromethane)sul- fonimide and lithium bis(fluorosulfonyl)imide dissolved in said aprotic organic liquid (g) and said second composite layer comprises

and dispersed within said matrix

(a') nanoparticles comprising one or more oxides of tungsten

(g') an aprotic organic liquid selected from the group consisting of ethylene carbonate, fluorinated ethylene carbonate, 1 ,2-propylene carbonate, fluorinated 1 ,2-propylene carbonate, 1 ,3-propylene carbonate, fluorinated 1 ,3-propylene carbonate and mixtures thereof

(h') optionally at least one electrolyte selected from the group consisting of lithium perchlorate, lithium trifluoromethylsulfonate, lithium bis(trifluoromethane)sul- fonimide and lithium bis(fluorosulfonyl)imide dissolved in said aprotic organic liquid (g').

The second composite layer of the above-defined specifically preferred article according to the invention is obtainable using the composition or according to the process described in a patent application filed by the same applicant on the same day as the present application. A second composite layer obtained by said process does not comprise a metal salt of formula (II) as defined above.

In certain cases, an article according to the invention further comprises a support layer attached to the surface of the first solid substrate facing away from the composite layer and/or a support layer attached to the surface of the second solid substrate facing away from said counter electrode layer. Preferably, a first support layer is attached to the surface of the first solid substrate facing away from the composite layer and a second support layer is attached to the surface of the second solid substrate facing away from said counter electrode layer. In this regard, it is particularly preferred that the first and second solid substrate comprise materials from the group of organic polymers and are in the form of foils, films, webs, and the first and second support layer comprise glass.

Furthermore, a third support layer may be attached to the surface of the first support layer facing away from the first solid substrate and/or a fourth support layer may be attached to the surface of the second support layer facing away from the second solid substrate. In this regard it is particularly preferred that a third support layer is attached to the surface of the first support layer facing away from the first solid substrate and a fourth support layer is attached to the surface of the second support layer facing away from the second solid substrate. In this regard, it is particularly preferred that the first, second, third and fourth support layer comprise glass.

Said support layers comprise one or more materials selected from the group consisting of glasses, metals and organic polymers. Preferred types of glass are e.g. float glass, low iron float glass, heat strengthened glass and chemically strengthened glass. Optionally, the glass has a low-emissivity (low-e) coating, sun-protection coating or any other coating on the surface facing outwardly.

Attaching said first resp. second support layer to said first resp. second solid substrate preferably comprises applying an adhesive between the support layer and the surface of the solid substrate to which said support layer has to be attached. Attaching said third resp. fourth support layer to said first resp. second support layer preferably comprises applying an adhesive. Suitable adhesives are thermoplastics, e.g. polyvinylbutyral, polyvinylalcohol, polyvinylacetate, ethylene-vinylacetate-copolymers, polyurethanes, ionomer resins (com- mercially available e.g. under the trade name SentryGlas®) and polymethylmethacrylate (PMMA).

A fifth aspect of the present invention relates to the use of a metal salt of formula (II) as defined above for preparing a composition comprising nanoobjects (a) as defined above dispersed in a carrier liquid (c) as defined above. Regarding preferred nanoobjects (a), metal salts (b) of formula (II) and a carrier liquids (c) and optional further constituents and combinations thereof, reference is made to the disclosure provided above in the context of the first aspect of the present invention.

Said suspensions can be prepared as described in WO 2016/128133, with the exception that a metal salt (b) of formula (II) as defined above is used as the dispersing agent instead of one of the metal salts which are disclosed in WO 2016/128133 as dispersing agents (in WO 2016/128133 also referred to as dispersants).

The present invention further relates to the use of an article as defined above resp., an electrochromic device as defined above in buildings, furniture, cars, trains, planes and ships as well as to the in facades, skylights, glass roofs, stair treads, glass bridges, cano- pies, railings, car glazing, train glazing.

The present invention further relates to insulating glass units, windows, rotating windows, turn windows, tilt windows, top-hung windows, swinging windows, box windows, horizontal sliding windows, vertical sliding windows, quarterlights, store windows, skylights, light domes, doors, horizontal sliding doors in double-skin facades, closed cavity facades, all- glass constructions, D3-facades (Dual, Dynamic Durable Facade), facade glass construction elements (e.g. but not limited to fins, louvres), interactive facades (facades reacting on an external impulse e.g. but not limited to a motion control, a radio sensor, other sensors) curved glazing, formed glazing, 3D three-dimensional glazing, wood-glass combinations, over head glazing, roof glazing, bus stops, shower wall, indoor walls, indoor separating elements in open space offices and rooms, outdoor walls, stair treads, glass bridges, canopies, railings, aquaria, balconies, privacy glass and figured glass. The present invention further relates to thermal insulation, i.e. insulation against heat, insulation against cold, sound insulation, shading and/or sight protection. The present invention is preferably useful when combined with further glass layers to an insulation glass unit (IGU), which can be used for building facades. The IGU might have a double (Pane 1 + Pane 2), or triple glazing (Pane 1 + Pane 2 + Pane 3), or more panes. The panes might have different thicknesses and different sizes. The panes might be of tempered glass, tempered safety glass, laminated glass, laminated tempered glass, safety glass. The device according to the present application may be used in any of the panes 1 , 2, 3. Materials can be put into the space between the panes. For example, but not limited such materials might be argon, xenon, nitrogen, wooden objects, metal objects, expanded metal, prismatic ob- jects, blinds, louvres, light guiding objects, light guiding films, light guiding blinds, 3-D light guiding objects, sun protecting blinds, movable blinds, roller blinds, roller blinds from films, translucent materials, capillary objects, honey comb objects, micro blinds, micro lamella, micro shade, micro mirrors insulation materials, aerogel, integrated vacuum insulation panels, holographic elements, integrated photovoltaics or combinations thereof. The present invention further relates to the use in heat-mirror glazing, vacuum glazing, multiple glazing and laminated safety glass.

The present invention further relates to the use in transportation units, preferably in boats, in vessels, in spacecrafts, in aircrafts, in helicopters, in trains, in automotive, in trucks, in cars e.g. but not limited to windows, separating walls, light surfaces and background light- ing, signage, pass protection, as sunroof.

The present invention is preferentially useful when combined with further glass layers to an insulation glass unit (IGU), which can be used for building facades. Examples

The invention is now further illustrated by means of non-limiting examples.

All compositions were obtained in an analogous manner as in the examples in WO 2016/128133. The nanoparticles were either commercially available or obtained by flame spray pyrolysis. All other constituents were all commercially available.

The dispersion stability of the compositions was evaluated as follows: A composition was considered instable if there was a phase separation after two hours such that there was a clear supernatant of 30 % or more in height regarding to the total filling height.

Example 1

Compositions 1-3 according to the first aspect of the present invention comprising

(a) nanoparticles comprising nickel oxide

(b) a metal salt of formula (II)

(c) ethanol

(d) a monomer selected from the group consisting of alkyl acrylates and alkyl meth- acrylates and a monomer selected from the group consisting of hydroxyalkyl acrylates and hydroxyalkyl methacrylates

(e) an initiator for initiating copolymerization of monomers (d) by UV irradiation (g) 1 ,2-propylene carbonate

were prepared. The concentrations of all constituents were in the above-defined preferred ranges.

For comparison, compositions 4 to 12 comprising the above-defined nanoparticles (a) and a carrier liquid (c), and either a commercially available dispersing agent (for details, see table 1 ) or Υ(Ν03)3·6 H2O instead of a metal salt of formula (II) were prepared. The use of Υ(Νθ3)3·6 H2O as a dispersing agent for nanoparticles is disclosed in WO 2016/128133 A1. As usual, the specific composition of the commercially available dispersing agents was not disclosed by the suppliers. For this reason, in table 1 some dispersing agents are identified by their trade names. The concentration of constituent (a) was the same as in the composition according to the invention.

All compositions met the above-defined condition of stability over two hours. The compositions according to table 1 were used as inks for preparing layers comprising the above-defined nanoparticles (a). The substrate was in each case a glass plate having a surface coated with indium-tin-oxide (ITO). A wet film was formed in each case by spin- coating the ink on said ITO-coated surface. After evaporation of the carrier liquid at ambient conditions the monomers (d) were copolymerized. The copolymerization was initiated by means of UV irradiation. Thereafter, the coated substrates were heated on a hot plate.

The electrochromic behavior of the layers obtained as described above was studied by means of single cycle cyclovoltammetry in the potential range -0.5 V to +2.2 V in a three electrode cell (reference: Ag/Ag⁺, counter electrode: Pt wire) using a 0.5 molar solution of lithium trifluoromethyl sulfonate in 1 ,2-propylene carbonate as the electrolyte.

Only the layers obtained from the composition according to the invention and the comparison compositions 4 and 5 exhibited reversible electrochromic behavior. These layers adopted a brown color when the potential was scanned in the anodic direction and discolored when the potential was scanned back in the cathodic direction. In contrast, most of the layers prepared using the comparison compositions did not show any electrochromic effect.

Table 1

No Carrier liquid Dispersing agents Electrochromic behavior scandium bis(trifluoro-

1 ethanol

methane)sulfonimide

2 ethanol zinc trifluoromethylsulfonate

coloring and subsequent dis¬

3 ethanol zinc bis(fluorosulfonyl)imide coloring

4 methanol Y(N0₃)3^*6H₂0

5 ethanol Y(N0₃)3^*6H₂0

6 2-propanol BYK-9077 (supplier: BYK)

Diethylphosphato-ethyl-

7 2-propanol

triethoxysilane

DISPERBYK-2164

8 2-propanol No electrochromic effect

(supplier: BYK)

2-(2-(2-Methoxyeth-

9 2-propanol

oxy ethoxy) acetic acid

10 2-propanol Polypropylene glycol-pol- yethylene glycol phosphate ester

Solsperse 41000

1 1 2-propanol

(supplier: Lubrizol)

DISPERBYK-1 1 1

12 methanol

(supplier: BYK)

Example 2

In further tests, the electrochromic behavior of nanoparticles comprising nickel oxide in layers having different structures was studied. The substrate was in each case a glass plate having a surface coated with indium-tin-oxide (ITO). Two different inks according to the invention were used. The first ink comprises

(a) nanoparticles comprising nickel oxide

(b) yttrium bis(trifluoromethane)sulfonimide

(c) ethanol.

The second ink comprises the same constituents (a), (b) and (c) like the first ink and further comprises

(d) a monomer selected from the group consisting of alkyl acrylates and alkyl methac- rylates and a monomer selected from the group consisting of hydroxyalkyl acrylates and hydroxyalkyl methacrylates

(e) an initiator for initiating copolymerization of monomers (d) by UV irradiation (g) 1 ,2-propylene carbonate.

Thus, the second ink is suitable for preparing a composite layer as defined above.

A first layer was prepared by spin-coating the first ink on the ITO-coated surface of a first substrate. After evaporation of the carrier liquid at ambient temperature the coated substrate was heated on a hot plate. A second layer was prepared by the following sequence of steps:

forming a wet film by spin-coating the first ink on the ITO-coated surface of a second substrate

evaporation of the carrier liquid at ambient conditions

forming a wet film by spin-coating the second ink on the surface of the dried film evaporation of the carrier liquid at ambient conditions

UV-initiated copolymerization of the monomers (d)

heating the coated substrate on a hot plate.

A third layer was prepared by the following sequence of steps:

forming a wet film by spin-coating the second ink on the ITO-coated surface of a third substrate

evaporation of the carrier liquid at ambient conditions

UV-initiated copolymerization of the monomers (d)

heating the coated substrate on a hot plate.

The electrochromic behavior of the layers obtained as described above was studied by means of multicycle cyclovoltammetry in the potential range -0.5 V to +1.2 V in a three electrode cell (reference: Ag/AgCI, counter electrode: Pt wire) using a 0.5 molar solution of lithium trifluoromethylsulfonate in 1 ,2-propylene carbonate as the electrolyte.

In the first voltage cycle each film adopted a brown color when the potential was scanned in the anodic direction and discolored when the potential was scanned back in the cathodic direction. Starting from the second cycle, the first as well as the second layer showed significant degradation, i.e. the current flow significantly decreased with each further voltage cycle. In contrast, the cyclovoltammogram of the third layer remained substantially unchanged between the second and the 100^th voltage cycle. UV-Vis spectra recorded during the cyclovoltammetry cycling indicate a completely reversible coloration/discoloration during each voltage cycle and substantially no change of the optical properties.

Example 3

The influence of the type of the metal salt used as the dispersing agent (either a metal salt according to formula (II) as defined above, or Υ(Ν03)3·6 H2O as disclosed in WO 2016/128133 A1 ) on the agglomeration and settling of dispersed nanoparticles of different compositions was studied.

Compositions 13-102 (see table 2) comprising

(a) nanoparticles comprising a compound selected from metal oxides, metal sulfides, metal selenides, metal tellurides and compounds of formula (I) as indicated in table (b) a metal salt as indicated in table 2 (concentration: 2 wt.-% based on the total weight of the nanoparticles (a))

(c) ethanol as the carrier liquid

were prepared. Compositions 13, 16, 19 and 22 which comprise Υ(Ν03)3·6 H2O are com- parison compositions. With the exception of composition 16, all compositions met the above-defined condition of stability over two hours.

For each composition, the D50 value of the hydrodynamic particle size was determined by a centrifugal sedimentation technique. The results are given in table 2.

Table 2

titanium yttrium bis(trifluoromethane)sul-

5 25 oxide fonimide

titanium

5 scandium trifluoromethylsulfonate 30 oxide

nickel oxcopper bis(trifluoromethane)sul-

5 15 ide fonimide

nickel oxzinc bis(trifluoromethane)sul-

5 17 ide fonimide

nickel oxnickel bis(trifluoromethane)sul-

5 16 ide fonimide

nickel ox¬

5 yttrium trifluoromethylsulfonate 15 ide

nickel ox¬

5 zinc trifluoromethylsulfonate 12 ide

nickel ox¬

5 lanthanum trifluoromethylsulfonate 18 ide

nickel ox¬

5 aluminum trifluoromethylsulfonate 12 ide

nickel ox¬

5 cerium trifluoromethylsulfonate 13 ide

nickel ox¬

5 copper trifluoromethylsulfonate 17 ide

nickel ox¬

5 nickel trifluoromethylsulfonate 17 ide

nickel ox¬

5 zinc tetracyanoborate 19 ide

nickel ox¬

5 copper tetracyanoborate 16 ide

nickel ox¬

5 zinc μ-fluoro-hexafluorodiborate 13 ide

nickel oxaluminum μ-fluoro-hexafluorodibo-

5 17 ide rate

nickel ox¬

5 calcium tetramethylaluminate 14 ide

nickel ox¬

5 barium tetramethylaluminate 12 ide

nickel ox¬

5 calcium tetramethoxyaluminate 13 ide nickel ox¬

5 magnesium tetrafluoroaluminate 19 ide

nickel oxaluminum μ-fluoro-hexamethyldialu-

5 12 ide minate

nickel oxcalcium μ-fluoro-hexamethyldialu-

5 16 ide minate

nickel ox¬

5 copper hexafluoroantimonate 16 ide

nickel ox¬

5 zinc hexafluoroantimonate 13 ide

nickel ox¬

5 nickel hexafluoroantimonate 12 ide

nickel ox¬

5 zinc bis- diphenylphosphinylimide 19 ide

nickel oxcalcium bis-diphe-

5 21 ide nylphosphinylimide

nickel oxcerium bis-diiso-

5 20 ide propylphosphinylimide

nickel ox¬

5 zinc methylsulfate 18 ide

nickel ox¬

5 yttrium perchlorate 17 ide

nickel ox¬

5 scandium perchlorate 21 ide

nickel ox¬

5 nickel perchlorate 18 ide

nickel ox¬

5 copper perchlorate 17 ide

nickel ox¬

5 nickel dicyanamide 12 ide

nickel ox¬

5 cobalt dicyanamide 14 ide

nickel ox¬

5 calcium dicyanamide 12 ide

cerium oxcopper bis(trifluoromethane)sul-

5 20 ide fonimide

cerium oxzinc bis(trifluoromethane)sul-

5 19 ide fonimide cerium oxnickel bis(trifluoromethane)sul-

5 23 ide fonimide

cerium ox¬

5 yttrium trifluoromethylsulfonate 14 ide

cerium ox¬

5 zinc trifluoromethylsulfonate 16 ide

cerium ox¬

5 lanthanum trifluoromethylsulfonate 18 ide

cerium ox¬

5 aluminum trifluoromethylsulfonate 17 ide

cerium ox¬

5 cerium trifluoromethylsulfonate 22 ide

cerium ox¬

5 copper trifluoromethylsulfonate 17 ide

cerium ox¬

5 nickel trifluoromethylsulfonate 23 ide

cerium ox¬

5 zinc bis-diphenylphosphinylimide 17 ide

cerium oxcerium bis-diiso-

5 15 ide propylphosphinylimide

vanadium yttrium bis(trifluoromethane)sul-

3 15 oxide fonimide

vanadium

3 nickel trifluoromethylsulfonate 22 oxide

zinc oxide 3 zinc perchlorate 25 zinc oxide 3 zinc trifluoromethylsulfonate 20 aluminum

3 aluminum perchlorate 23 oxide

aluminum

5 aluminum trifluoromethylsulfonate 18 oxide

Silicon oxcopper bis(trifluoromethane)sul-

5 25 ide fonimide

Silicon oxzinc bis(trifluoromethane)sul-

7 20 ide fonimide

Silicon oxnickel bis(trifluoromethane)sul-

7 23 ide fonimide

99 CsPbls 3 copper trifluoromethylsulfonate 23

100 CsPbBrs 3 copper trifluoromethylsulfonate 21

101 CsSnCIs 3 yttrium perchlorate 18

102 CsGeCIs 3 copper tetracyanoborate 24

The results in table 2 show that with metal salts of formula (II) as defined above stable dispersions were obtained even at higher concentration of nanoparticles than possible with Υ(Ν03)3·6 hhO as the dispersing agent. At equal concentration of the nanoparticles, in the compositions according to the invention the D50 value (median value) of the hydrodynamic particle size was smaller than in the comparison compositions comprising the same kind of nanoparticles. The reduction of the hydrodynamic size indicates that the particles are less agglomerated. A small hydrodynamic particle size of the nanoparticles in the ink allows for obtaining coatings having low haze values (little scattered light). This is favorable for optoelectronic devices. The possibility to obtain stable dispersions with a higher concentration of nanoparticles improves the coating efficiency, because less carrier liquid has to be removed and a higher dry film thickness is obtainable per coating step.

Example 4

The electrochromic behavior of a composite layer according to the invention and of a composite layer prepared from an ink comprising Υ(Ν03)3·6 H2O instead of a metal salt of formula (II ) as defined above was studied.

A composition according to the invention comprising

(a) nanoparticles comprising nickel oxide

(b) yttrium bis(trifluoromethane)sulfonimide

(c) ethanol

was prepared. The concentrations of all constituents were in the above-defined preferred ranges. For comparison, a composition comprising the above-defined constituents (a), (c), (d), (e) and (g) and Υ(Ν0₃)₃·6 H2O instead of a (b) the metal salt of formula (II) was prepared.

The substrate was in each case a glass plate having a surface coating of fluorine-doped tin-oxide (FTO). Composite layers were prepared by the following sequence of steps: forming a wet film by spin-coating the ink on the FTO-coated surface of said substrate

evaporation of the carrier liquid at ambient conditions

UV-initiated copolymerization of the monomers (d)

heating the coated substrate on a hot plate.

The electrochromic behavior of the composite layers obtained as described above was studied by means of cyclic voltammetry in the potential range of from 2.0 V to 5.0 V vs. Li in a three electrode cell using a 0.5 molar solution of lithium trifluoromethylsulfonate in 1 ,2- propylene carbonate as the electrolyte and lithium as the reference electrode with different scan rates. Different samples of each composite layer were used for the different scan rates. Simultaneously with the cyclovoltammograms, the light transmission at a wavelength of 550 nm was recorded. Data obtained from these measurements are collected in table 3.

Table 3

The composite layers obtained from the ink according to the invention exhibit a higher switching speed than those obtained from the comparison ink, as evident by the less pronounced dependency of the transferred charge during the anodic scan (determined in known manner from the area of the anodic scan of the cyclovoltammogram) on the scan rate. The composite layers obtained from the ink according to the invention also exhibit a higher coloration efficiency (CE) which is a crucial figure for electrochromic electrodes and which is defined as change in optical density (OD) per charge (CE = AOD/Q =

Example 5

The agglomeration behavior of compositions according to the invention comprising the constituents

(a) nanoparticles comprising nickel oxide

(b) yttrium bis(trifluoromethane)sulfonimide

(c) ethanol

and an electrolyte (h) (see table 4, concentration in the above-defined preferred range) was monitored as described above. In each case either no visible change or only a slight colloidal turbidity was observed.

Table 4

Electrolyte (h) observation

Lithium hexafluorophosphate slight colloidal turbidity

Lithium tetrafluoroborate slight colloidal turbidity

Lithium nitrate slight colloidal turbidity

Lithium bis(fluorosulfonyl)imide no visible change

Lithium bis(trifluoromethane)sulfonimide no visible change

Lithium chloride slight colloidal turbidity

Lithium bromide slight colloidal turbidity

Lithium difluorophosphate no visible change

Lithium trifluoromethyl sulfonate no visible change

Lithium bis(oxalate)borate slight colloidal turbidity Lithium difluoro(oxalate)borate slight colloidal turbidity

Lithium perchlorate no visible change

Claims

1. Composition , comprising

oxides, sulfides, selenides, and tellurides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon and

compounds of formula (I)

wherein A is a monovalent organic cation or an alkali metal cation,

D is Pb, Sn, or Ge,

X is CI , Br, or I ,

i is an integer from 0 to 6

(b) one or more salts of formula (I I)

M^a+(Z )a (I I)

wherein

M^a+ is a metal cation wherein a is 2, 3, 4 or 5, and

Z^" is selected from the group consisting of

(Z-1 ) [BX4]^" wherein X is selected from -OTeFs, -CN and R

(Z-2) [X3B-E-BX3]^" wherein

X is selected from F, -OTeFs, -CN and R and E is selected from F and CN

(Z-3) [CBi i Hi2-mXm]- wherein

X is selected from F, CI, Br, I and R;

and m is an integer selected from the range of 1 to 12

(Z-4) [CBgHio-mXm]^" wherein

X is selected from F, CI, Br, I and R;

and m is an integer selected from the range of 1 to 10

(Z-5) [AIX4]- wherein X is selected from F, CI, Br, I, -OR, R, and -OC{X'_mR3-m} wherein m is an integer selected from the range of 0 to 3 and X' is selected from F, CI, Br, I and -OR

(Z-6) [X3AI-E-AIX3]- wherein

X is selected from of F, CI, Br, I, -OR, R, and -OC{X'_mR3-m} wherein m is an integer selected from the range of 0 to 3 and X' is selected from F, CI, Br, I and -OR

and E is selected from CN and F

(Z-7) [EX₆]- wherein

E is selected from P, As and Sb

X is selected from F, CN, -OTeFs and R

with the exception of PF6^"

(Z-8) [X5E-A-EX5]^" wherein

E is selected from P, As and Sb

X is selected from F, CN, -OTeFs, and R;

A is selected from F and CN

(Z-9) [E(S0₂X)m]- wherein

X is selected from F and R;

E is selected from O, N and C

(Z-10) [N(OPR₂)₂]-

(Z-12) N(CN)₂-

wherein in the anions selected from the group consisting of (Z-1 ) to (Z-13) R, if present, is selected from the group consisting of

(c) a carrier liquid having 0 to 8 carbon atoms per molecule.

Composition according to claim 1 wherein the molar percentage of metal ions M^a+ of the metal salts (b) of formula (I I) is in the range of from 0.02 to 6 mol%, based on the total amount of

the mols of metal in the metal ions Ma+ of the metal salts (b) of formula (I I) and the total amount of mols of metals of the metal compounds in the nanoob- jects (a).

Composition according to any preceding claim, wherein

(b) in said salts of formula (II)

said metal cation M^a+ is a cation of a metal selected from the group consisting of transition metals, rare earth metals, Mg, Ca, Sr, Ba, Al , In , Ga, Sn , Pb, Bi, Zn , Cd, and Hg .

Composition according to any preceding claim, wherein

(b) in said salts of formula (I I) said anion Z^~ is selected from the group consisting of (Z-1 ) to (Z-12) as defined in claim 1 .

Composition according to any preceding claim, wherein

(a) said nanoobjects comprise one or more electrochromic compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14 with the exception of carbon

and

(c) said carrier liquid has a boiling point of less than 120 °C. Composition according to claim 5, further comprising

(d) one or more kinds of radically polymerizable moieties which are polymerizable by radical polymerization (e) one or more initiators for initiating radical polymerization of said one or more kinds of polymerizable moieties

(f) optionally one or more organic polymers.

Composition according to claim 6, further comprising

(g) an aprotic organic liquid having a boiling point of 120 °C or higher

(h) optionally at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺

(i) optionally electronically conductive nanoobjects not comprising any compounds selected from the group consisting of oxides of elements selected from the group consisting of transition metals, rare earth elements, and elements of groups 12, 13 and 14.

Composition according to any of claims 6 and 7, wherein

(a) said nanoobjects are nanoparticles comprising one or more oxides of nickel

(b) said metal salts of formula (II) are selected from the group consisting of scandium bis(trifluoromethane)sulfonimide, yttrium bis(trifluoromethane)sul- fonimide, aluminum bis(trifluoromethane)sulfonimide, lanthanum bis(trifluoro- methane)sulfonimide, cerium bis(trifluoromethane)sulfonimide, nickel bis(fluorosulfonyl)imide, copper bis(fluorosulfonyl)imide, zinc bis(fluorosul- fonyl)imide, yttrium trifluoromethylsulfonate, aluminum trifluoromethyl- sulfonate, lanthanum trifluoromethylsulfonate, cerium trifluoromethylsulfonate, and yttrium fluorosulfonate

(c) said carrier liquid is selected from the group consisting of ethanol, methanol, 2-propanol, 2-methyl tetrahydrofuran, and mixtures thereof,

said composition further comprising

(e) optionally one or more initiators for initiating radical polymerization of said monomers (d)

(h) optionally at least one electrolyte selected from the group consisting of lithium perchlorate, lithium trifluoromethylsulfonate, lithium bis(trifluoromethane)sul- fonimide and lithium bis(fluorosulfonyl)imide

(i) optionally nanowires comprising materials selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel and alloys of two or more metals selected from the group consisting of silver, copper, gold, platinum, tungsten and nickel.

9. Process for preparing a layer comprising

compounds of formula (I)

wherein A is a monovalent organic cation or an alkali metal cation,

D is Pb, Sn, or Ge,

X is CI, Br, or I,

i is an integer from 0 to 6

(b) one or more salts of formula (II)

M^a+(Z )a (II)

wherein

M^a+ is a metal cation wherein a is 2, 3, 4 or 5, and

Z^" is an anion as defined in claim 1 or 4

on a surface of a solid substrate,

said process comprising the steps of

forming on a surface of said solid substrate a wet film by applying a composition according to any of claims 1 to 8 to said surface of said solid substrate removing said carrier liquid (c) from the wet film formed on said surface of said solid substrate.

10. Process according to claim 9, wherein

said composition applied to said surface of said solid substrate comprises (d) one or more kinds of polymerizable moieties, and said process further comprises the step of

polymerizing the polymerizable moieties on said surface of said solid substrate.

1 1. Article comprising

a solid substrate having a surface

and, arranged on said surface of said solid substrate, a layer comprising

compounds of formula (I)

wherein A is a monovalent organic cation or an alkali metal cation,

D is Pb, Sn, or Ge,

X is CI, Br, or I,

i is an integer from 0 to 6

(b) one or more salts of formula (II)

M^a+(Z )a (II)

wherein

M^a+ is a metal cation wherein a is 2, 3, 4 or 5, and

Z^" is an anion as defined in claim 1 or 4. Article according to claim 1 1 , wherein said layer arranged on said surface of said solid substrate is a composite layer comprising

a matrix formed of one or more organic polymers

and dispersed within said matrix

(b) one or more salts of formula (II)

M^a+(Z )a (II)

wherein

M^a+ is a metal cation wherein a is 2, 3, 4 or 5, and

Z^" is an anion as defined in claim 1 or 4

(g) an aprotic organic liquid having a boiling point of 120 °C or higher

(h) optionally at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺.

Article according to claim 12, wherein said composite layer comprises

a matrix formed of one or more organic polymers which are copolymerization products of one or more monomers selected from the group consisting of alkyl acrylates and alkyl methacrylates and one or more monomers selected from the group of hydroxyalkyl acrylates and hydroxyalkyl methacrylates and dispersed within said matrix

(a) nanoparticles comprising one or more oxides of nickel

(b) one or more salts of formula (II) selected from the group consisting of scandium bis(trifluoromethane)sulfonimide, yttrium bis(trifluoro- methane)sulfonimide, aluminum bis(trifluoromethane)sulfonimide, lanthanum bis(trifluoromethane)sulfonimide, cerium bis(trifluoro- methane)sulfonimide, nickel bis(fluorosulfonyl)imide, copper bis(fluorosulfonyl)imide, zinc bis(fluorosulfonyl)imide, yttrium trifluoro- methylsulfonate, aluminum trifluoromethylsulfonate, lanthanum trifluo- romethylsulfonate, cerium trifluoromethylsulfonate, and yttrium fluorosulfonate (g) an aprotic organic liquid selected from the group consisting of ethylene carbonate, fluorinated ethylene carbonate, 1 ,2-propylene carbonate, fluorinated 1 ,2-propylene carbonate, 1 ,3-propylene carbonate, fluorinated 1 ,3-propylene carbonate and mixtures thereof (h) optionally at least one electrolyte selected from the group consisting of lithium perchlorate, lithium trifluoromethylsulfonate, lithium bis(trifluoro- methane)sulfonimide and lithium bis(fluorosulfonyl)imide dissolved in said aprotic organic liquid (g).

14. Article according to claim 12 or 13, further comprising

a second solid substrate having a surface

arranged on said surface of said second solid substrate, a counter electrode layer

a separator layer sandwiched between and electronically separating said composite layer and said counter electrode layer. 15. Article according to claim 14,

wherein said separator layer comprises

a matrix formed of one or more organic polymers

and dispersed within said matrix

(g") an aprotic organic liquid having a boiling point of 120 °C or higher, (h") optionally at least one electrolyte having cations selected from the group consisting of H⁺, Li⁺, Na⁺ and K⁺ dissolved in said aprotic organic liquid (g").

16. Article according to claim 14, wherein

said composite layer arranged on said surface of said first solid substrate is a com- posite layer as defined in claim 13

and

said separator layer is a separator layer as defined in claim 15

and

said counter electrode layer is a second composite layer comprising

- a matrix formed of one or more organic polymers which are copolymerization products of one or more monomers selected from the group consisting of alkyl acrylates and alkyl methacrylates and one or more monomers selected from the group of hydroxyalkyl acrylates and hydroxyalkyl methacrylates and dispersed within said matrix

(a') nanoparticles comprising one or more oxides of tungsten

(h') optionally at least one electrolyte selected from the group consisting of lithium perchlorate, lithium trifluoromethylsulfonate, lithium bis(trifluoro- methane)sulfonimide and lithium bis(fluorosulfonyl)imide dissolved in said aprotic organic liquid (g')

with the proviso that at least one said layers comprises an electrolyte (h), (h'), (h").

17. Use of a metal salt of formula (II) as defined in any of claims 1 , 3 and 4 for preparing a composition comprising nanoobjects comprising one or more compounds selected from the group consisting of

and

compounds of formula (I)

X is CI, Br, or I,

i is an integer from 0 to 6

dispersed in a carrier liquid having 0 to 8 carbon atoms per molecule.