Polyoxometalates for the preparation of optical metal oxide layers

Abstract

The present invention relates to polyoxometallate compounds having polyoxometalate clusters containing Group 5 elements, formulations comprising the polyoxometallate compounds, and methods of using the formulations and polyoxometallate compounds to prepare optical metal oxide layers. The resulting optical metal oxide layers are particularly suitable for use in optical devices such as, for example, augmented reality (AR) and / or virtual reality (VR) devices.

Description

[Technical field]

[0001] The present invention relates to polyoxometallate compounds, formulations, and methods for preparing optical metal oxide layers.

[0002] The polyoxometallate compounds according to the invention contain polyoxometallate clusters containing two or three group 5 elements. The formulations according to the invention comprise a polyoxometallate compound and one or more formulation media. The method for preparing an optical metal oxide layer according to the invention comprises applying the formulation to the surface of a substrate and converting it into an optical metal oxide layer. The resulting optical metal oxide layer is particularly suitable for optical applications and can be used in optical devices, such as, for example, diffraction gratings for augmented reality (AR) and / or virtual reality (VR) devices. The optical metal oxide layer exhibits (a) favorable optical properties such as a high refractive index (RI) of greater than 1.7, preferably greater than 2.0, at wavelengths of 520 nm or less, low absorption, and low degree of haze formation, (b) favorable mechanical properties such as low shrinkage, (c) favorable coating properties such as dense layers and flat surface structures, and (d) favorable filling properties such as uniform filling of topographical features on patterned substrates.

[0003] The embodiments of the present invention allow the preparation of optical metal oxide layers on the surfaces of both patterned and non-patterned substrates. The metal oxide layers can form various structures, such as layers covering the surfaces of non-patterned substrates and / or fillings covering topographical features, such as gaps, on the surfaces of patterned substrates, thereby providing highly refractive optical structures. In particular, the embodiments of the present invention allow the preparation of highly optical gap-filling with low overburden, thus enabling easy and cost-effective mass production of complex optical devices by avoiding typical problems that arise when layer deposition or gap-filling is performed by physical vapor deposition (PVD) or chemical vapor deposition (CVD) techniques, such as incomplete or excessive gap-filling due to unfavorable deposition and layer growth characteristics, such as reduced or increased deposition or growth rates at corners and edges.

[0004] Embodiments of the present invention are particularly suitable for preparing optical metal oxide layers with high refractive index for optical devices such as, for example, diffraction gratings in AR and / or VR devices.

[0005] Finally, the present invention provides an optical device, preferably an AR and / or VR device, comprising an optical metal oxide layer obtainable by the method according to the present invention or prepared by using the formulation according to the present invention. [Background technology]

[0006] State-of-the-art optical devices usually include optical gratings made of composite materials with a substrate as a support and a complex interlaced pattern thereon, the pattern being composed of different layers or stacks of layers. The creation of such complex interlaced patterns usually requires a structuring process, which becomes increasingly difficult as the size of the prepared structure dimensions decreases.

[0007] In addition to a wide range of possible uses in various application areas such as spectroscopy or optical storage systems (CD, DVD, etc.), diffraction gratings are a core component of so-called XR devices, which are mainly glass. In this context, R stands for the term "real" and X indicates different attributes such as virtual, augmented, mixed, etc. Thus, diffraction gratings form part of the core of the so-called optical engine in XR devices, specifically in augmented and mixed reality glasses. Virtual reality glasses, when built as head-mounted displays, often consist of conventional liquid crystal (LC) organic light-emitting diode (OLED) displays embedded in the device and therefore do not necessarily require a diffraction grating. In contrast, augmented and mixed reality glasses are designed to enable consumers to obtain the best possible visual impression of their environment as if they were not wearing glasses at all. However, they also make it possible to provide digital information to aid it and to project it into the individual's field of vision. Additional digital information is collected from recognizing and analyzing the environment, and the individual probes or looks at what he or she is currently looking at. To convey the supporting digital information and project it to the individual's eye, the augmented or mixed reality glasses comprise an information supply unit coupled to an optical waveguide system that transmits the optically encoded supporting information directly to the lens of the glasses. Here, the information passes through a diffraction grating that couples the incoming light to the lens and splits it according to its angular information and its spectral band by diffraction. After the in-coupling of the light, the lens acts as a waveguide that allows the transmission of light to and within the pupil of the individual. The position of the light in-coupling is independent of any preferred position and therefore of the influence of technical needs. The transverse direction of the light in the lens is determined by the diffraction grating that diffracts or splits the light. At a specific position in the lens, the second and third diffraction gratings function to change the transverse direction of the light, so that the light is projected into the user's pupil. The transverse of the light in the glasses is achieved by total internal reflection (TIR) ​​of the light, which therefore bounces several times between glass interfaces until it reaches another diffraction grating that changes the internal TIR direction of the light (see FIG. 2).The second and third gratings can be geometrically aligned in different directions relative to the first and incoupling gratings, for example by a certain angular distortion of the longitudinal axis, thus changing the propagation direction of the totally internally reflected light. Needless to say, the lens itself or the material from which it is made must not be absorbing. Otherwise, the auxiliary information will not reach the user's pupil, or will only reach it with a greatly reduced light intensity. This process works regardless of the use of reflective or transmissive gratings. Usually, lenses are equipped with both types of gratings to properly guide the light. It should also be mentioned that there is a difference in the optical performance of reflective and transmissive gratings, but that this is no more important in the context of the present invention. The basic structure of the gratings is very similar, which is more important in this respect.

[0008] Nevertheless, there are different designs and structures to obtain a waveguide, such as surface relief (SR) or volume phase holographic (VPH) gratings. Both types are very similar in appearance. In the simplest case, the grating is somehow attached on the surface of a waveguiding material, here a lens. The grating itself consists of an array of microstructures, mainly, but not limited to, trenches of a first material type Material01 with a refractive index RI01. The geometry of the trenches can range from rectangular, to V-shaped trenches, U-shaped trenches, etc. The width, including structures with different widths, the geometry of the trenches, their pitch, as well as their depth, including different depths, are specially designed to affect the diffraction pattern of the diffracted incident light.

[0009] In the case of SR gratings (SRG), trenches or structures of a first material type (material 01) with a refractive index (RI01) are filled by a second material type (material 02) with a refractive index (RI02), which is incrementally different from RI01 (see figures 1 and 3). For completeness, it should be mentioned that material 01 or material 02 may be composed of a stack of structured layers, each containing different material compositions with different refractive indices, stacked on top of each other, thereby forming material 01 or material 02 with an effective or graded refractive index RI01 or RI02, respectively. It should be noted that the (effective or graded) refractive indices RI01 and RI02 depend on the refractive index of the waveguide or lens, which is the material of the glasses. If glass lenses with a high refractive index (n03>1.46) are used, the (effective or graded) refractive indices of material 01 and material 02 are considered higher than the refractive index of the lens itself, thereby allowing the RI value of 2.0 to be reached and exceeded. High performance gratings, particularly SR type high performance gratings, can be fabricated using standard lithography and deposition techniques known from microfabrication, for example, integrated circuit manufacturing.

[0010] Such standard techniques typically involve physical vapor deposition (PVD) or chemical vapor deposition (CVD) processes and often suffer from incomplete gap filling due to unfavorable deposition and / or layer growth deposition characteristics, including increased deposition and / or growth rates at corners and edges. Such incomplete gap filling results in the formation of voids in the structures filled by the PVD and CVD materials. In addition to the formation of voids, the surface of the substrate is covered by a PVD and / or CVD layer that is approximately as thick as the maximum depth of the deepest structure filled by the deposited gap filling material (see Figures 4 and 5). However, in some applications, it may be necessary to expose the surface of the substrate and make it available for further processing. As a result, the undesired overburden layer from the PVD or CVD needs to be removed, for example, by chemical mechanical planarization (CMP), without harming the original substrate surface underneath. Although CMP is very well established in the process of manufacturing integrated circuits, CMP is a time-consuming and expensive process that may be considered a potential economic drawback for the mass production of state-of-the-art optical devices, particularly for the mass production of diffraction gratings. It is therefore desirable to have a solution for advanced, cost-effective fabrication of optical gratings where gap filling does not require CMP (see FIG. 6).

[0011] The present invention addresses various shortcomings of the techniques for preparing optical gratings for state-of-the-art optical devices as described above. The focus here is on improved optical properties, improved mechanical properties, improved coating properties and improved filling properties. Furthermore, it is of interest. Summary of the Invention

[0012] Means for solving the problem It is an object of the present invention to provide polyoxometallate compounds, formulations, and methods for preparing optical metal oxide layers that are particularly suitable for optical applications and may be used in optical devices, such as, for example, diffraction gratings for AR and / or VR devices. The resulting optical metal oxide layers exhibit (a) favorable optical properties, such as a high refractive index (RI) of greater than 1.7, preferably greater than 2.0, at wavelengths of 520 nm or less, low absorption, and low degree of haze formation, (b) favorable mechanical properties, such as low shrinkage, (c) favorable coating properties, such as dense layers and flat surface structures, and (d) favorable filling properties, such as uniform filling of topographical features on patterned substrates.

[0013] It is a further object of the present invention to provide polyoxometallate compounds, formulations, and methods that allow for easy and cost-effective preparation of optical metal oxide layers.

[0014] It is a further object of the present invention to enable the preparation of optical metal oxide layers on the surfaces of both patterned and non-patterned substrates. The metal oxide layers can form a variety of structures, such as, for example, layers covering the surfaces of non-patterned substrates and / or fillers covering topographical features, such as, for example, gaps, on the surfaces of patterned substrates, thereby providing highly refractive optical structures.

[0015] It is therefore an object of the present invention to provide polyoxometallate compounds, formulations and methods for preparing optical metal oxide layers that allow to obtain a high degree of optical gap filling at low overburden, thus enabling easy and cost-effective mass production of complex optical devices.

[0016] It is a further object of the present invention to provide polyoxometallate compounds, formulations, and methods for preparing optical metal oxide layers, which avoid typical problems that arise when layer deposition or gap filling is performed by PVD or CVD techniques, such as unfavorable deposition and layer growth characteristics, such as incomplete or excessive gap filling due to reduced or increased deposition or growth rates at corners and edges.

[0017] It is an object of the present invention that the polyoxometallate compounds and formulations are particularly suitable for the preparation of optical metal oxide layers with high refractive index for optical devices such as, for example, diffraction gratings in AR and / or VR devices.

[0018] Finally, it is an object of the present invention to provide an optical device, preferably an AR and / or VR device, comprising an optical metal oxide layer obtainable by the method according to the present invention or prepared by using the formulation according to the present invention, thereby exhibiting the above mentioned beneficial effects.

[0019] Summary of the Invention The inventors have surprisingly found that the above object is achieved by the following embodiments. A polyoxometallate compound containing a polyoxometallate cluster, the polyoxometallate cluster preferably comprising two or three Group 5 elements selected from V, Nb and Ta.

[0020] A formulation for preparing an optical metal oxide layer, the formulation comprising: (i) a polyoxometallate compound containing polyoxometallate clusters, the polyoxometallate clusters preferably comprising one, two or three Group 5 elements selected from V, Nb and Ta; (ii) one or more formulation vehicles.

[0021] The following steps (a) to (c): (a) providing a formulation according to the present invention; (b) applying the formulation to a surface of a substrate; (c) converting the formulation onto a surface of the substrate into an optical metal oxide layer.

[0022] Finally, there is provided an optical device comprising an optical metal oxide layer obtainable or obtained by the method according to the invention or prepared by using the formulation according to the invention, the optical device being preferably an augmented reality (AR) and / or virtual reality (VR) device.

[0023] Preferred embodiments of the invention are described below and set out in the dependent claims. [Brief description of the drawings]

[0024] [Figure 1] 1 is a schematic cross-sectional view of an SR grating having material 01 and material 02, where the refractive index of material 01, IR01, is incrementally different from the refractive index of material 02, IR02.

[0025] [Diagram 2] Schematic cross-section of an SR grating, which allows for optical diffraction, including the propagation of diffracted light within a waveguide (e.g., a lens) by total internal reflection.

[0026] [Diagram 3] FIG. 1 is a schematic cross-sectional view of an SR grating providing gaps (trenches) that are filled with a high refractive index material (material 02), the refractive index of which is incrementally different from that of material 01 adjacent to the gaps (trenches).

[0027] [Figure 4] Schematic of PVD or CVD mediated gap filling process and removal of unwanted overburden.

[0028] [Diagram 5]Schematic of a PVD or CVD mediated gap-fill process that creates and leaves voids in the gaps and deposited layers.

[0029] [Figure 6] FIG. 1 is a schematic diagram of a gap-filling process using a formulation containing a metal complex of the present invention or the formulation being converted to a metal oxide.

[0030] [Figure 7] Mass spectral analysis of the compound from Example 2 (tetrabutylammonium polyniobate). The peak at m / z 2831.56 Da represents hexakis(tetrabutylammonium) decanioate occurring as an ion pair or cluster ion. The peak at m / z 2590.29 Da represents a cluster ion of hexakis(tetrabutylammonium) decanioate with loss of one tetrabutylammonium ligand.

[0031] [Figure 8] Refractive index and absorptivity of layers obtained from the material of Example 2 after coating on a quartz wafer and calcining for 60 minutes at 300° C., 400° C. and 500° C., respectively, as described in Example 4.

[0032] [Figure 9] SEM cross-section of an array of trenches having a depth of 450 nm, an opening width at half depth of 47 nm, and a pitch of 450 nm as an illustrative example of a substrate with topographical features on its surface (see Example 5).

[0033] [Figure 10] 4. SEM cross-section of an array of trenches after layer coating and pre-baking as described in Example 5 (top layer covering the trenches is 916 nm thick).

[0034] [Figure 11] 4A-4C are SEM cross-sections of an array of trenches after layer coating, subsequent pre-baking, and baking as described in Example 5 (thickness of the top layer covering the trenches is 748 nm).

[0035] [Figure 12] Refractive index and absorptance of layers obtained from the material of Example 2 doped with lanthanum oxide precursor after coating on a quartz wafer and calcining at 300° C., 400° C. and 500° C. for 60 minutes, respectively, as described in Example 6.

[0036] [Figure 13] Refractive index and absorptance of layers obtained from the material of Example 2 doped with lanthanum oxide precursor after coating on a quartz wafer as described in Example 7 and calcining at 300°C, 400°C and 500°C for 60 minutes, respectively.

[0037] [Figure 14] Mass spectrogram of the compound (tetrabutylammonium polytantalate) from Example 8. The peak at m / z 3710.9 Da represents hexakis(tetrabutylammonium) decatantalate occurring as an ion pair or cluster ion. The ions at m / z 3952.1 Da and 3469.9 Da may represent cluster ions of hexakis(tetrabutylammonium) decatantalate with either the addition or removal of tetrabutylammonium ions, respectively.

[0038] [Figure 15] 13 is an SEM cross-section of an array of trenches after layer coating and pre-baking as described in Example 10 (top layer covering the trenches is 614 nm thick).

[0039] [Figure 16] 13. SEM cross-section of an array of trenches after layer coating, followed by pre-baking, temperature ramping, and final baking as described in Example 10 (top layer covering the trenches is 240 nm thick).

[0040] [Figure 17]Mass spectrum of the compound (tetrabutylammonium poly(niobate-tantalate)) from Example 11. Peak assignments are shown in Table 6.

[0041] [Figure 18] Mass spectrum of the compound (tetrabutylammonium poly(niobate-titanate)) from Example 13. Further discussion is provided in Example 13.

[0042] [Figure 19] Mass spectrum of the compound (tetrabutylammonium poly(niobate-titanate)) from Example 13. Further discussion is provided in Example 13.

[0043] [Figure 20] Mass spectrum of the compound (tetrabutylammonium poly(niobate-vanadate)) from Example 17. Peak assignments are shown in Table 10. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] definition As used herein, the term "polyoxometalate" refers to polyatomic ions, usually anions, consisting of three or more transition metal oxyanions linked together by shared oxygen atoms to form a closed three-dimensional framework, also called a cluster. The metal atoms are usually transition metals of group 6 (Mo, W), or less commonly group 5 (V, Nb, Ta) or group 4 (Ti, Zr, Hf), in their higher oxidation states. They are usually colorless or orange diamagnetic anions. Two large families are recognized, the isopolymetalates, which are composed of only one type of metal and oxide, and the heteropolymetalates, which are composed of one type of metal, oxide, and main group oxyanions (e.g., phosphates, silicates, etc.). To balance the charge, polyoxometalate compounds may contain one or more different cations (e.g., alkali metal cations, alkaline earth metal cations, ammonium cations, etc.).

[0045] Group 5 metal polyoxometalates are described below. (1) A. Llordes et al., Polyoxometalates and colloidal nanocrystals as building blocks for metal oxide nanocomposite films, J. Mater. Chem., 2011, 21, 11631-11638.

[0046] (2) W. G. K. Lemperer et al., An 17 O NMR Study of Hydrolyzed Nb(V)in Weakly Acidic and Basic Aqueous Solution,Eur.J.Inorg.Chem.,2013,1762-1771.

[0047] In the context of the present invention, the term "formulation vehicle" or the plural "formulation vehicles", as used herein, refers to one or more compounds that act as a solvent, suspending agent, carrier and / or matrix for the polyoxometalate compound and any other components included in the formulation. A formulation vehicle is generally an inert compound that does not react with the polyoxometalate compound and the other components. A formulation vehicle may be a liquid compound, a solid compound, or a mixture thereof. Typically, a formulation vehicle is an organic compound.

[0048] As used herein, the term "surfactant" refers to an additive that reduces the surface tension of a given formulation.

[0049] As used herein, the term "wetting and dispersing agent" refers to an additive that increases the diffusivity and permeability of a given formulation, thus reducing the tendency of molecules to stick to each other.

[0050] As used herein, the term "adhesion promoter" refers to an additive that increases the adhesion of a given formulation.

[0051] As used herein, the term "polymeric matrix" refers to an additive that functions as a polymeric matrix for one or more components of a given formulation.

[0052] As used herein, the term "optical device" refers to a device that contains one or more optical components for forming a light beam, including, but not limited to, gratings, lenses, prisms, mirrors, optical windows, filters, polarizing optics, UV and IR optics, and optical coatings. Preferred optical devices in the context of the present invention are augmented reality (AR) glasses and / or virtual reality (VR) glasses.

[0053] Preferred Embodiments Polyoxometalate Compounds The present invention relates to a polyoxometalate compound containing a polyoxometalate cluster, the polyoxometalate cluster preferably containing two or three group 5 elements selected from V, Nb and Ta. The group 5 elements contained in the polyoxometalate cluster of the polyoxometalate compound are different from each other. The polyoxometalate cluster contained in the polyoxometalate compound preferably contains two group 5 elements selected from V, Nb and Ta.

[0054] In a preferred embodiment of the invention, the polyoxometallate cluster contained in the polyoxometallate compound further comprises one or more group 4 elements, preferably selected from Ti, Zr and Hf. When more group 4 elements are contained in the polyoxometallate cluster, the group 4 elements are different from each other. In a more preferred embodiment of the invention, the polyoxometallate cluster contained in the polyoxometallate compound further comprises Ti.

[0055] In a preferred embodiment of the invention, the polyoxometalate clusters are selected from the group consisting of poly(vanadate-niobate), poly(vanadate-tantalate), poly(niobate-tantalate), poly(vanadate-niobate-titanate), poly(vanadate-tantalate-titanate), poly(niobate-tantalate-titanate), poly(vanadate-niobate-zirconate), poly(vanadate-tantalate-zirconate), ), poly(niobate-tantalate-zirconate), poly(vanadate-niobate-hafniate), poly(vanadate-tantalate-hafniate), poly(niobate-tantalate-hafniate), poly(vanadate-niobate-tantalate-titanate), poly(vanadate-niobate-tantalate-zirconate), and poly(vanadate-niobate-tantalate-hafniate).

[0056] Preferred poly(vanadate-niobate)s are tetra(vanadate-niobate), hexa(vanadate-niobate), deca(vanadate-niobate), and dodeca(vanadate-niobate). More preferred poly(vanadate-niobate)s are hexa(vanadate-niobate) and deca(vanadate-niobate).

[0057] Preferred poly(vanadate-tantalate)s are tetra(vanadate-tantalate), hexa(vanadate-tantalate), deca(vanadate-tantalate), and dodeca(vanadate-tantalate). More preferred poly(vanadate-tantalate)s are hexa(vanadate-tantalate) and deca(vanadate-tantalate).

[0058] Preferred poly(niobate-tantalate)s are tetra(niobate-tantalate), hexa(niobate-tantalate), deca(niobate-tantalate), and dodeca(niobate-tantalate). More preferred poly(niobate-tantalate)s are hexa(niobate-tantalate) and deca(niobate-tantalate).

[0059] In a preferred embodiment of the present invention, the polyoxometalate cluster contained in the polyoxometalate compound is represented by formula (1): [M 1 x1 M 2 x2 O y ] m Formula (1) [In the formula, M 1 is preferably a mixture of two or three group 5 elements selected from V, Nb and Ta, and preferably M 1 is a mixture of V and Nb, V and Ta, Nb and Ta, or V, Nb and Ta; M 2 is preferably one or a mixture of two or more group 4 elements selected from Ti, Zr and Hf, and preferably M 2 is Ti, Zr or Hf, more preferably Ti; O is oxygen, x1 is an integer of 3 to 40, preferably 4 to 32, more preferably 6 to 24, even more preferably 6 to 12, and most preferably 10; x2 is an integer of 0 to 40, preferably 0 to 32, more preferably 0 to 24, even more preferably 1 to 12, and most preferably 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; Preferably, x1+x2=3 to 40, preferably 4 to 32, more preferably 6 to 24, even more preferably 6 to 12, and most preferably 10; y is an integer of 8 to 160, preferably 12 to 120, more preferably 22 to 96, even more preferably 28 to 72, and most preferably 28 to 40; m represents the total charge of the polyoxometalate cluster, preferably m=S1 * x1+S2 * x2-2 * y, and S1 is M 1 Preferably, S1 is 2, 3, 4 or 5, more preferably S1 is 5, and S2 is M 2 wherein S2 represents the oxidation state value, preferably S2 is 2, 3 or 4, more preferably S2 is 4.

[0060] In a more preferred embodiment of the present invention, the polyoxometalate cluster contained in the polyoxometalate compound is represented by formula (1): [M 1 x1 M 2 x2 O y ] m Formula (1) [In the formula, M 1 is a mixture of V and Nb, V and Ta, Nb and Ta, or V, Nb and Ta; M 2 is Ti, Zr or Hf, preferably Ti; O is oxygen, x1 is an integer of 3 to 40, preferably 4 to 32, more preferably 6 to 24, even more preferably 6 to 12, and most preferably 10; x2 is an integer of 0 to 40, preferably 0 to 32, more preferably 0 to 24, even more preferably 1 to 12, and most preferably 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; x1+x2=3 to 40, preferably 4 to 32, more preferably 6 to 24, even more preferably 6 to 12, and most preferably 10; y is an integer of 8 to 160, preferably 12 to 120, more preferably 22 to 96, even more preferably 28 to 72, and most preferably 28 to 40; m represents the total charge of the polyoxometalate cluster; m=S1 * x1+S2 * x2-2 *y, S1 is 5, and S2 is 4].

[0061] In the most preferred embodiment of the present invention, the polyoxometalate cluster contained in the polyoxometalate compound is represented by formula (1): [M 1 x1 M 2 x2 O y ] m Formula (1) [In the formula, M 1 is a mixture of V and Nb, V and Ta, Nb and Ta, or V, Nb and Ta; M 2 is Ti, O is oxygen, x1 is an integer of 4 to 32, preferably 6 to 24, more preferably 6 to 12, and most preferably 10; x2 is an integer of 0 to 32, preferably 0 to 24, more preferably 1 to 12, and most preferably 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; x1+x2=4 to 32, preferably 6 to 24, more preferably 6 to 12, and most preferably 10; y is an integer of 12 to 120, preferably 22 to 96, more preferably 28 to 72, and most preferably 28 to 40; m represents the total charge of the polyoxometalate cluster; m=S1 * x1+S2 * x2-2 * y, S1 is 5, and S2 is 4].

[0062] Particularly preferred embodiments of formula (1) are the following formulas (1-1) to (1-9): [M 1 4O 12 ] 4- Formula (1-1) [M 1 6O 19 ] 8- Formula (1-2) [M 1 7O 22 ]9- Formula (1-3) [M 1 10 O 28 ] 6- Formula (1-4) [M 1 12 O 40 ] 14- Formula (1-5) [M 1 20 O 54 ] 8- Formula (1-6) [M 1 24 O 72 ] 24- Formula (1-7) [M 1 27 O 76 ] 17- Formula (1-8) [M 1 32 O 96 ] 32- Formula (1-9) [In the formula, M 1 is a mixture of V and Nb, V and Ta, Nb and Ta, or V, Nb and Ta].

[0063] In the mixture, the individual components (V and Nb, V and Ta, Nb and Ta, or V, Nb and Ta) are 1 can be present in any integer ratio based on their respective exponents.

[0064] Formulae (1-2) and (1-4) are most preferred.

[0065] Optionally, in formula (1-1) to formula (1-9), one or more M 1 M 2 can be replaced by M 2 is Ti, Zr or Hf, preferably Ti. 1 For each such substitution of M, the total negative charge of the polyoxometalate cluster increases by 1. In this case, M 2 The octahedral coordination of is maintained.

[0066] The special good shape is the following formula (1-2-1)~formula (1-2-4) and formula (1-4-1)~formula (1-4-8)である [M 1 5M 2 O 19 ] 9- Formula (1-2-1) [M 1 4M 2 2O 19 ] 10- Formula (1-2-2) [M 1 3M 2 3O 19 ] 11- Formula (1-2-3) [M 1 2M 2 4O 19 ] 12- Formula (1-2-4) [M 1 9M 2 O 28 ] 7- Formula (1-4-1) [M 1 8M 2 2O 28 ] 8- Formula (1-4-2) [M 1 7M 2 3O 28 ] 9- Formula (1-4-3) [M 1 6M 2 4O 28 ] 10- Formula (1-4-4) [M 1 5M 2 5O 28 ] 11- Formula (1-4-5) [M 1 4M 2 6O 28 ] 12- Formula (1-4-6) [M 1 3M 2 7O 28 ] 13- Formula (1-4-7) [M 1 2M 2 8O 28 ]14- Formula (1-4-8) [In the formula, M 1 is a mixture of V and Nb, V and Ta, Nb and Ta, or V, Nb and Ta, and M 2 is Ti, Zr or Hf, preferably Ti.

[0067] In a preferred embodiment of the invention, the polyoxometalate compounds are, independently of each other, H + , Li + , Na + , K + , Rb + , Cs + , N.H. 4-a R a + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ R is an organic group; and a is an integer of 0 to 4, preferably 0 or 4, and more preferably 4.

[0068] Preferably, R is, independently of one another at each occurrence, selected from an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms or a hydroxyalkyl group having 1 to 4 carbon atoms, most preferably methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, t-butyl, hydroxymethyl, 1-hydroxyethyl, 1-hydroxypropyl, 2-hydroxypropyl, 1-hydroxybutyl, and 2-hydroxybutyl.

[0069] NH 4-a R a + It is particularly preferred that all R in are the same.

[0070] Polyoxometallate compounds according to the present invention may contain one or more waters of crystallization in their solid form and therefore may exist as hydrates.

[0071] compound The present invention further relates to a formulation for preparing an optical metal oxide layer, said formulation comprising: (i) a polyoxometallate compound containing polyoxometallate clusters, the polyoxometallate clusters preferably comprising one, two or three Group 5 elements selected from V, Nb and Ta; (ii) one or more formulation vehicles.

[0072] When two or three Group 5 elements are included in the polyoxometallate cluster of a polyoxometallate compound, the Group 5 elements are different from each other.

[0073] Preferably, the polyoxometallate clusters contained in the polyoxometallate compounds in the formulation contain one or two Group 5 elements selected from V, Nb and Ta. More preferably, the polyoxometallate clusters contained in the polyoxometallate compounds in the formulation contain one Group 5 element which is Nb.

[0074] In a preferred embodiment of the formulation for preparing an optical metal oxide layer according to the invention, the polyoxometallate cluster further comprises one or more group 4 elements, preferably selected from Ti, Zr and Hf. If more group 4 elements are contained in the polyoxometallate cluster, the group 4 elements are different from each other. In a more preferred embodiment of the formulation for preparing an optical metal oxide layer according to the invention, the polyoxometallate cluster further comprises Ti.

[0075] In a preferred embodiment of the formulation for preparing an optical metal oxide layer according to the invention, the polyoxometalate clusters are selected from the group consisting of poly(vanadate), poly(niobate), poly(tantalate), poly(vanadate-titanate), poly(niobate-titanate), poly(tantalate-titanate), poly(vanadate-zirconate), poly(niobate-zirconate), poly(tantalate-zirconate), poly(vanadate-hafniate), poly(niobate-hafniate), poly(tantalate-hafniate), poly(vanadate-niobate), poly(vanadate-tantalate), poly(niobate-tantalate), poly(vanadate-niob ... In one embodiment, the poly(vanadate-niobate-tantalate-titanate), poly(vanadate-niobate-titanate), poly(vanadate-niobate-zirconate), poly(vanadate-tantalate-zirconate), poly(niobate-tantalate-zirconate), poly(vanadate-niobate-hafniate), poly(vanadate-tantalate-hafniate), poly(vanadate-niobate-tantalate-titanate), poly(vanadate-niobate-tantalate-zirconate), and poly(vanadate-niobate-tantalate-hafniate).

[0076] Preferred poly(vanadates) are tetra(vanadate), hexa(vanadate), deca(vanadate), and dodeca(vanadate). More preferred poly(vanadates) are hexa(vanadate) and deca(vanadate).

[0077] Preferred poly(niobate)s are tetra(niobate), hexa(niobate), deca(niobate), and dodeca(niobate). More preferred poly(niobate)s are hexa(niobate) and deca(niobate).

[0078] Preferred poly(tantalates) are tetra(tantalate), hexa(tantalate), deca(tantalate), and dodeca(tantalate). More preferred poly(tantalates) are hexa(tantalate) and deca(tantalate).

[0079] Preferred poly(vanadate-niobate)s are tetra(vanadate-niobate), hexa(vanadate-niobate), deca(vanadate-niobate), and dodeca(vanadate-niobate). More preferred poly(vanadate-niobate)s are hexa(vanadate-niobate) and deca(vanadate-niobate).

[0080] Preferred poly(vanadate-tantalate)s are tetra(vanadate-tantalate), hexa(vanadate-tantalate), deca(vanadate-tantalate), and dodeca(vanadate-tantalate). More preferred poly(vanadate-tantalate)s are hexa(vanadate-tantalate) and deca(vanadate-tantalate).

[0081] Preferred poly(niobate-tantalate)s are tetra(niobate-tantalate), hexa(niobate-tantalate), deca(niobate-tantalate), and dodeca(niobate-tantalate). More preferred poly(niobate-tantalate)s are hexa(niobate-tantalate) and deca(niobate-tantalate).

[0082] In a preferred embodiment of the present invention, the polyoxometallate clusters contained in the polyoxometallate compounds in the formulation are represented by formula (1): [M 1 x1 M 2 x2 O y ] m Formula (1) [In the formula, M 1is preferably one or a mixture of two or three group 5 elements selected from V, Nb and Ta, and preferably M 1 is a mixture of V and Nb, V and Ta, Nb and Ta, or V, Nb and Ta; M 2 is preferably one or a mixture of two or more group 4 elements selected from Ti, Zr and Hf, and preferably M 2 is Ti, Zr or Hf, more preferably Ti; O is oxygen, x1 is an integer of 3 to 40, preferably 4 to 32, more preferably 6 to 24, even more preferably 6 to 12, and most preferably 10; x2 is an integer of 0 to 40, preferably 0 to 32, more preferably 0 to 24, even more preferably 1 to 12, and most preferably 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; Preferably, x1+x2=3 to 40, preferably 4 to 32, more preferably 6 to 24, even more preferably 6 to 12, and most preferably 10; y is an integer of 8 to 160, preferably 12 to 120, more preferably 22 to 96, even more preferably 28 to 72, and most preferably 28 to 40; m represents the total charge of the polyoxometalate cluster, preferably m=S1 * x1+S2 * x2-2 * y, and S1 is M 1 Preferably, S1 is 2, 3, 4 or 5, more preferably S1 is 5, and S2 is M 2 wherein S2 represents the oxidation state value, preferably S2 is 2, 3 or 4, more preferably S2 is 4.

[0083] In a more preferred embodiment of the present invention, the polyoxometallate clusters contained in the polyoxometallate compounds in the formulation are represented by formula (1): [M 1 x1 M 2 x2 O y ]m Formula (1) [In the formula, M 1 is one or a mixture of two or three group 5 elements selected from V, Nb and Ta, preferably M 1 is a mixture of V and Nb, V and Ta, Nb and Ta, or V, Nb and Ta; M 2 is Ti, Zr or Hf, preferably Ti; O is oxygen, x1 is an integer of 3 to 40, preferably 4 to 32, more preferably 6 to 24, even more preferably 6 to 12, and most preferably 10; x2 is an integer of 0 to 40, preferably 0 to 32, more preferably 0 to 24, even more preferably 1 to 12, and most preferably 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; x1+x2=3 to 40, preferably 4 to 32, more preferably 6 to 24, even more preferably 6 to 12, and most preferably 10; y is an integer of 8 to 160, preferably 12 to 120, more preferably 22 to 96, even more preferably 28 to 72, and most preferably 28 to 40; m represents the total charge of the polyoxometalate cluster; m=S1 * x1+S2 * x2-2 * y, S1 is 5, and S2 is 4].

[0084] In the most preferred embodiment of the present invention, the polyoxometallate clusters contained in the polyoxometallate compounds in the formulation are represented by formula (1): [M 1 x1 M 2 x2 O y ] m Formula (1) [In the formula, M 1 is a mixture of V and Nb, V and Ta, Nb and Ta, or V, Nb and Ta; M 2 is Ti, O is oxygen, x1 is an integer of 4 to 32, preferably 6 to 24, more preferably 6 to 12, and most preferably 10; x2 is an integer of 0 to 32, preferably 0 to 24, more preferably 1 to 12, and most preferably 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; x1+x2=4 to 32, preferably 6 to 24, more preferably 6 to 12, and most preferably 10; y is an integer of 12 to 120, preferably 22 to 96, more preferably 28 to 72, and most preferably 28 to 40; m represents the total charge of the polyoxometalate cluster; m=S1 * x1+S2 * x2-2 * y, S1 is 5, and S2 is 4].

[0085] Particularly preferred embodiments of formula (1) are the following formulas (1-1) to (1-9): [M 1 4O 12 ] 4- Formula (1-1) [M 1 6O 19 ] 8- Formula (1-2) [M 1 7O 22 ] 9- Formula (1-3) [M 1 10 O 28 ] 6- Formula (1-4) [M 1 12 O 40 ] 14- Formula (1-5) [M 1 20 O 54 ] 8- Formula (1-6) [M 1 24 O 72 ] 24- Formula (1-7) [M 127 O 76 ] 17- Formula (1-8) [M 1 32 O 96 ] 32- Formula (1-9) [In the formula, M 1 is V, Nb or Ta, or a mixture of V and Nb, V and Ta, Nb and Ta, or V, Nb and Ta].

[0086] In the mixture, the individual components (V and Nb, V and Ta, Nb and Ta, or V, Nb and Ta) are 1 can be present in any integer ratio based on their respective exponents.

[0087] Formulae (1-2) and (1-4) are most preferred.

[0088] Optionally, in formula (1-1) to formula (1-9), one or more M 1 M 2 can be replaced by M 2 is Ti, Zr or Hf, preferably Ti. 1 For each such substitution of M, the total negative charge of the polyoxometalate cluster increases by 1. In this case, M 2 The octahedral coordination of is maintained.

[0089] Particularly preferred embodiments are represented by the following formulae (1-2-1) to (1-2-4) and (1-4-1) to (1-4-8). [M 1 5M 2 O 19 ] 9- Formula (1-2-1) [M 1 4M 2 2O 19 ] 10- Formula (1-2-2) [M 1 3M 2 3O 19 ] 11- Formula (1-2-3) [M 1 2M2 4O 19 ] 12- Formula (1-2-4) [M 1 9M 2 O 28 ] 7- Formula (1-4-1) [M 1 8M 2 2O 28 ] 8- Formula (1-4-2) [M 1 7M 2 3O 28 ] 9- Formula (1-4-3) [M 1 6M 2 4O 28 ] 10- Formula (1-4-4) [M 1 5M 2 5O 28 ] 11- Formula (1-4-5) [M 1 4M 2 6O 28 ] 12- Formula (1-4-6) [M 1 3M 2 7O 28 ] 13- Formula (1-4-7) [M 1 2M 2 8O 28 ] 14- Formula (1-4-8) [In the formula, M 1 is V, Nb or Ta, or a mixture of V and Nb, V and Ta, Nb and Ta, or V, Nb and Ta; M 2 is Ti, Zr or Hf, preferably Ti.

[0090] In a preferred embodiment of the invention, the polyoxometalate compounds in the formulation are, independently of each other, H + , Li + , Na + , K + , Rb + , Cs + , N.H. 4-aR a + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ R is an organic group; and a is an integer of 0 to 4, preferably 0 or 4, and more preferably 4.

[0091] Preferably, R is, independently of one another at each occurrence, selected from an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms or a hydroxyalkyl group having 1 to 4 carbon atoms, most preferably methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, t-butyl, hydroxymethyl, 1-hydroxyethyl, 1-hydroxypropyl, 2-hydroxypropyl, 1-hydroxybutyl, and 2-hydroxybutyl.

[0092] NH 4-a R a + It is particularly preferred that all R in are the same.

[0093] Preferably, the content of the polyoxometallate compound in the formulation is in the range of 0.1 w / w% to 50 w / w%, preferably 0.5 w / w% to 40 w / w%, more preferably 1 w / w% to 30 w / w%, based on the total mass of the formulation.

[0094] In a preferred embodiment of the invention, the one or more formulation media are solution media and / or dispersion media. The formulation media are selected to improve the application, wetting, deposition properties, packing properties and / or stability of the formulation. Any formulation medium can be used as long as it dissolves or disperses the polyoxometallate compounds contained in the formulation according to the invention.

[0095] In a more preferred embodiment of the present invention, the one or more formulation media is selected from water, alcohols, carboxylic acids, and mixtures thereof.

[0096] In the most preferred embodiments of the present invention, the one or more formulation media is selected from water, alcohol, and mixtures thereof.

[0097] Preferred alcohols are C1-C12 alkyl alcohols, C1-C4 alkoxy-C1-C12 alkyl alcohols, C6-C10 aryl alcohols, and / or C6-C10 aryl-C1-C4 alkyl alcohols, such as, preferably, methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, allyl alcohol, vinyl alcohol, methoxy-propanol, methoxy-butanol, methoxy-pentanol, methoxy-hexanol, methoxy-heptanol, methoxy-octanol, methoxy-nonanol, methoxy-decanol, ethoxy-propanol, ethoxy-butanol, ethoxy-pentanol, ethoxy-hexanol, ethoxy-heptanol, ethoxy-octanol, ethoxy-nonanol, ethoxy-decanol, phenol, cresol, naphthol, and benzyl alcohol.

[0098] Preferred carboxylic acids are C1-C12 alkyl carboxylic acids, C6-C10 aryl carboxylic acids, and / or C6-C10 aryl-C1-4 alkyl carboxylic acids, such as, preferably, formic acid, acetic acid, propionic acid, benzoic acid, and benzilic acid.

[0099] Particularly preferred formulation vehicles are selected from 1-methoxy-2-propanol, n-butanol, a mixture of 1-methoxy-2-butanol and water, and a mixture of n-butanol and water.

[0100] Binary, ternary, quaternary or higher mixtures of any of the foregoing formulation vehicles are preferably used in the present invention.

[0101] In a preferred embodiment of the invention, the formulation further comprises (iii) one or more additives selected from surfactants, wetting and dispersing agents, adhesion promoters, and polymer matrices.

[0102] Preferred surfactants are surface-active substances, preferably comprising surface-active metal oxides and / or surface-active organic compounds, which may include nonionic surfactants, anionic surfactants, and amphoteric surfactants, which may be coordinating or non-coordinating.

[0103] Examples of nonionic surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, and 30 polyoxyethylene cetyl ether; polyoxyethylene fatty acid diesters; polyoxyethylene fatty acid monoesters; polyoxyethylene polyoxypropylene block polymers; acetylene alcohols; acetylene glycols; polyethoxylates of acetylene alcohols; acetylene glycol derivatives such as polyethoxylates of acetylene glycols; fluorine-containing surfactants such as FLUORAD (trade name, manufactured by Sumitomo 3M Limited), MEGAFAC (trade name, manufactured by DIC Cooperation), and SURFLON (trade name, manufactured by Asahi Glass Co. Ltd. 5); or organosiloxane surfactants such as KP341 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.). Examples of the acetylene glycol include 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3,6-dimethyl-4-octyne-3,6-diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,5-dimethyl-1-hexyne-3-ol, 2,5-dimethyl-3-10-hexyne-2,5-diol, and 2,5-dimethyl-2,5-hexanediol.

[0104] Examples of anionic surfactants include ammonium salts or organic amine salts of alkyldiphenyl ether disulfonic acids, ammonium salts or organic amine salts of alkyldiphenyl ether sulfonic acids, ammonium salts or organic amine 15 salts of alkylbenzene sulfonic acids, ammonium salts or organic amine salts of polyoxyethylene alkyl ether sulfates, and ammonium salts or organic amine salts of alkyl sulfates.

[0105] Examples of amphoteric surfactants include 2-alkyl-N-carboxymethyl-N-20 hydroxyethylimidazolium betaine, lauric acid amidopropyl hydroxysulfone betaine, and the like.

[0106] Preferred surface active metal oxides are selected from the list consisting of aluminum oxide, calcium oxide, silica and zinc oxide. Such surface active metal oxides are preferably present as fine powders, more preferably as nanoparticles, which are optionally surface treated.

[0107] Preferred surface-active organic compounds are surface-active non-polymeric compounds or surface-active polymeric organic compounds, the surface-active non-polymeric compounds being preferably selected from the list consisting of alcohols, alkoxylates, aromatics, ketones, esters, modified ureas, silanes, siloxanes and soap-based foam stabilizers, optionally functionalized and / or modified, and the surface-active polymeric compounds being preferably selected from the list consisting of hydroxy polyesters, maleic resins, polyacrylates, polyethers, polyesters, polysilanes, silicone resins and waxes, optionally functionalized and / or modified, and optionally present as copolymers. In a preferred embodiment, the surface-active organic compounds are used as a solution.

[0108] Preferred silanes are polyether-modified silanes, polyester-modified silanes, and polyether-polyester-modified silanes. Preferred siloxanes are polyether-modified siloxanes, polyester-modified siloxanes, and polyether-polyester-modified siloxanes.

[0109] Preferred polyacrylates are modified polyacrylates, preferably silicone modified polyacrylates, polyether macromer modified polyacrylates, and optionally silicone and polyether macromer modified polyacrylates present as copolymers.

[0110] Preferred polysilanes are polyether-modified polysilanes (eg, PEG-silanes 6-9), polyester-modified polysilanes, and polyether-polyester-modified polysilanes.

[0111] Preferred silicone resins are polyether modified polysiloxanes, preferably polyether modified polydialkylsiloxanes, more preferably polyether modified polymethylalkylsiloxanes, most preferably polyether modified polydimethylsiloxanes and polyether modified hydroxy-functional polydimethylsiloxanes; polyester modified polysiloxanes, preferably polydialkylsiloxanes, more preferably polyester modified polymethylalkylsiloxanes, most preferably polyester modified polydimethylsiloxanes and polyester modified hydroxy-functional polydimethylsiloxanes; polyether-polyester modified polysiloxanes, preferably polyether-polyester modified polydialkylsiloxanes, more preferably polyether-polyester modified polymethylalkylsiloxanes, most preferably polyether-polyester modified polydimethylsiloxanes and polyether-polyester modified hydroxy-functional polydimethylsiloxanes; epoxy functional polysiloxanes, preferably epoxy functional polydialkylsiloxanes, more preferably epoxy functional polymethylalkylsiloxanes, most preferably Preferably, epoxy-functional polydimethylsiloxane; acrylic-functional polysiloxane, preferably acrylic-functional polydialkylsiloxane, more preferably acrylic-functional polymethylalkylsiloxane, most preferably acrylic-functional polydimethylsiloxane; polyether-modified acrylic-functional polysiloxane, preferably polyether-modified acrylic-functional polydialkylsiloxane, more preferably polyether-modified acrylic-functional polymethylalkylsiloxane, most preferably polyether-modified acrylic-functional polydimethylsiloxane; polyester-modified acrylic-functional polysiloxane, preferably polyester-modified acrylic-functional polydialkylsiloxane, more preferably polyester-modified acrylic-functional polymethylalkylsiloxane, most preferably polyester-modified acrylic-functional polydimethylsiloxane; and aralkyl-modified polysiloxane, preferably aralkyl-modified polydialkylsiloxane, more preferably aralkyl-modified polymethylalkylsiloxane, most preferably aralkyl-modified polydimethylsiloxane, optionally present as a copolymer.

[0112] Preferred surfactants are commercially available from BYK-Chemie GmbH (Wesel, Germany) and are offered as surface additives. Preferred surfactants include BYK-300, BYK-301, BYK-302, BYK-306, BYK-307, BYK-310, BYK-313, BYK-315N, BYK-320, BYK-322, BYK-323, BYK-325N, BYK-326, BYK-327, BYK-329, BYK-330, BYK-331, BYK-332, BYK-333, BYK-342, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349, BYK-350, BYK-352, BYK-353, BYK-354, BYK-355, BYK-356, BYK-357, BYK-358, BYK-359, BYK-360, BYK-361, BYK-362, BYK-363, BYK-364, BYK-365, BYK-366, BYK-367, BYK-368, BYK-369, BYK-370, BYK-371, BYK-372, BYK-373, BYK-374, BYK-375, BYK-376, BYK-377, BYK-378, BYK-379, BYK-380, BYK-381, BYK-382, BYK-383, BYK-384, BYK K-354, BYK-355, BYK-356, BYK-358N, BYK-359, BYK-360P, BYK-361N, BYK-364P, BYK-366P, BYK-368P, BYK370, BYK375, BYK-377, BYK-378, B YK-381, BYK-390, BYK-392, BYK-394, BYK-399, BYK-2616, BYK-3400, BYK-3410, BYK-3420, BYK-3450, BYK-3451, BYK-3455, BYK-3456, BYK-3 480, BYK-3481, BYK-3499, BYK-3550, BYK-3560, BYK-3565, BYK-3566, BYK-3750, BYK-3751, BYK-3752, BYK-3753, BYK-3754, BYK-3760, BYK -3761, BYK-3762, BYK-3763, BYK-3764, BYK-3770, BYK-3771, BYK-3780, BYK-3900P, BYK3902P, BYK-3931P, BYK3932P, BYK-3933P, BYK-8020 , BYK-8070, BYK-9890, BYK-DYNWET800, BYK-S706, BYK-S732, BYK-S740, BYK-S750N, BYK-S760, BYK-S780, BYK-S782, BYK-SILCELAN3700, B YK-SILCLEAN3701, BYK-SILCLEAN3710, BYK-SILCLEAN3720, BYK-UV3500, BYK-UV3505, BYK-UV3510, BYK-UV3530, BYK-UV3535, BYK-UV3570,BYK-UV3575, BYK-UV3576, BYKETOL-AQ, BYKETOL-OK, BYKETOL-PC, BYKETOL-SPECIAL, BYKETOL-WA, NANOBYK-3603, NANOBYK-3605, NANOBYK-3620, NANOBYK-3650, NANOBYK-3652, and NANOBYK-3822.

[0113] Wetting and dispersing agents used in the present invention are additives that provide both wetting and / or stabilizing effects to formulations containing fine solid particles. They provide a fine and uniform distribution of solid particles in the formulation medium, preferably a liquid formulation medium, ensuring the long-term stability of such systems. The formulation medium may include water and any organic solvent of various polarities. In addition, they provide improved wetting of solids and prevent particles from agglomerating by various mechanisms (e.g., electrostatic effects, steric effects, etc.).

[0114] Preferably, the wetting and dispersing agent is an organic polymer or copolymer having polar functional groups selected from amino groups; amide groups; carbamate groups; carbonate groups; acid groups, preferably boric acid groups, boronic acid groups, carboxylic acid groups, sulfate groups, sulfonic acid groups, phosphoric acid groups, phosphonic acid groups, and phosphinic acid groups; ester groups, preferably boric acid ester groups, boronate ester groups, carboxylic acid ester groups, sulfate ester groups, sulfonic acid ester groups, phosphoric acid ester groups, phosphonic acid ester groups, and phosphinic acid ester groups; ether groups; hydroxy groups; keto groups; and urea groups, and the organic polymer or copolymer may be present as a complex, derivative and / or salt, preferably as a salt. Preferred salts are ammonium salts, alkylammonium salts, alkylolammonium salts, or alkali metal salts, such as Li, Na, K, and Rb salts, preferably. The polar functional groups may also be called pigment affinity groups or filler affinity groups. In a preferred embodiment, the wetting and dispersing agent is used as a solution.

[0115] More preferably, the wetting and dispersing agent is an organic polymer or copolymer selected from acrylates; amides; carboxylic acids; and esters, which may be present as complexes, derivatives and / or salts, preferably as salts, which may be further functionalized with one or more polar functional groups as mentioned above. Preferred salts are ammonium salts, alkylammonium salts, alkylolammonium salts, or alkali metal salts, preferably Li, Na, K and Rb salts. In a preferred embodiment, the wetting and dispersing agent is used as a solution.

[0116] The wetting and dispersing agent may be present in a mixture, preferably with a polysiloxane copolymer.

[0117] Preferred wetting and dispersing agents are commercially available from BYK-Chemie GmbH (Wesel, Germany). Suitable wetting and dispersing agents include ANTI-TERRA-202, ANTI-TERRA-203, ANTI-TERRA-204, ANTI-TERRA-205, ANTI-TERRA-210, ANTI-TERRA-250, ANTI-TERRA-U, ANTI-TERRA-U80, ANTI-TERRA-U100, BYK-151, BYK-153, BYK-154, BYK-155 / 35, BYK-156, BYK-220S, BYK-1160, BYK-1162, BYK-1165, BYK-9076, BYK- 9077, BYK-GO8702, BYK-GO8720, BYK-P104, BYK-P104S, BYK-P105, BYK-SYNERGIST2100, BYK-SYNERGIST2105, BYK-W900, BYK-W903, BYK-W907, BYK-W908, BYK-W909, BYK-W940, BYK-W961, BYK-W966, BYK-W969, BYK-W972, BYK-W974, BYK-W980, BYK-W985, BYK-W995, BYK-W996, BYK-W9010, BYK-W9011, BYK-W9012, BYKJET-9131, BYKJET-9132, BYKJET-9133, BYKJET-9142, BYKJET-9150, BYKJET-9151, BYKJET-9152, BYKJET-9170, BY KJET-9171, BYKUMEN, DISPERBYK, DISPERBYK-101N, DISPERBYK-102, DISPERBYK-103, DISPERBYK-106, DISPERBYK-107, DISPERBYK-108, DISPE RBYK-109, DISPERBYK-110, DISPERBYK-111, DISPERBYK-115, DISPERBYK-118, DISPERBYK-130, DISPERBYK-140, DISPERBYK-142, DISPERBYK-1 45, DISPERBYK-161, DISPERBYK-162, DISPERBYK-162TF, DISPERBYK-163, DISPERBYK-163TF, DISPERBYK-164, DISPERBYK-165, DISPERBYK-166,DISPERBYK-167、DISPERBYK-167TF、DISPERBYK-168、DISPERBYK-168TF、DISPERBYK-169、DISPERBYK-170、DISPERBYK-171、DISPERBYK-174、DISPERBYK-180、DISPERBYK-181、DISPERBYK-182、DISPERBYK-184、DISPERBYK-185、DISPERBYK-187、DISPERBYK-190、DISPERBYK-190BF、DISPERBYK-191、DISPERBYK-192、DISPERBYK-193、DISPERBYK-194N、DISPERBYK-199、DISPERBYK-199BF、DISPERBYK-2000、DISPERBYK-2001、DISPERBYK-2008、DISPERBYK-2009、DISPERBYK-2010、DISPERBYK-2012、DISPERBYK-2013、DISPERBYK-2014、DISPERBYK-2015、DISPERBYK-2015BF、DISPERBYK-2018、DISPERBYK-2019、DISPERBYK-2022、DISPERBYK-2023、DISPERBYK-2025、DISPERBYK-2026、DISPERBYK-2030、DISPERBYK-2050、DISPERBYK-2055、DISPERBYK-2059、DISPERBYK-2060、DISPERBYK-2061、DISPERBYK-2062、DISPERBYK-2070、DISPERBYK-2080、DISPERBYK-2081、DISPERBYK-2096、DISPERBYK-2117、DISPERBYK-2118、DISPERBYK-2150、DISPERBYK-2151、DISPERBYK-2152、DISPERBYK-2155、DISPERBYK-2155TF、DISPERBYK-2157、DISPERBYK-2158、DISPERBYK-2159、DISPERBYK-2163、DISPERBYK-2163TF、DISPERBYK-2164、DISPERBYK-2190、DISPERBYK-2200、DISPERBYK-2205、DISPERBYK-2290、DISPERBYK-2291、DISPERPLAST-1142, DISPERPLAST-1148, DISPERPLAST-1150, DISPERPLAST-1180, DISPERPLAST-I, and DISPERPLAST-P.

[0118] Preferred adhesion promoters are block copolymers, preferably high molecular weight block copolymers; copolymers with functional groups, preferably hydroxy-functional copolymers with acid groups, styrene-ethylene / butylene-styrene block copolymers functionalized with maleic anhydride (SEBS), carboxylated SEBS functionalized with maleic anhydride, SEBS functionalized with glycidyl methacrylate, polyolefin block copolymers functionalized with maleic anhydride, and ethylene octene copolymers functionalized with maleic anhydride; and polymers with functional groups, preferably polymers with acid groups, and polypropylene functionalized with maleic anhydride. In a preferred embodiment, the adhesion promoter is used as a solution.

[0119] Preferred adhesion promoters are commercially available from BYK-Chemie GmbH (Wesel, Germany). Preferred adhesion promoters are BYK-4500, BYK-4509, BYK-4510, BYK-4511, BYK-4512, BYK-4513, SCONA TPKD8102PCC, SCONA TSIN4013GC, SCONA TSPOE1002GBLL, SCONA TPPP2112FA, SCONA TPPP2112GA, SCONA TPPP8112GA, SCONA TSKD9103, SCONA TPPP8112FA, SCONA TPKD8304PCC, and SCONA TSPP10213GB.

[0120] Preferred polymer matrices are polymethylmethacrylate, polyvinylpyrrolidone, polycarbonate, polystyrene, polymethylpentene, and silicone.

[0121] It is particularly preferred that combinations of two or more of the above additives are present in the formulation.

[0122] In a preferred embodiment of the present invention, the content of the additive in the formulation is, based on the total mass of the formulation, from more than 0 w / w% to less than 10 w / w%, preferably from more than 0.01 w / w% to less than 9 w / w%, more preferably from more than 0.05 w / w% to less than 7.5 w / w%, and most preferably from more than 0.1 w / w% to less than 5.0 w / w%.

[0123] In a preferred embodiment of the invention, the formulation comprises one or more further metal complexes which may act as further metal oxide precursors. In such a case, a mixed optical metal oxide layer can be formed comprising a metal oxide derived from the polyoxometallate compound and a further metal oxide derived from a further metal oxide precursor.

[0124] Preferred further metal complexes comprise one or more trivalent or tetravalent metals, preferably selected from the list consisting of Sc, Y, La, Ti, Zr, Hf and Sn, more preferably one or more tetravalent metals selected from the list consisting of Ti, Zr, Hf and Sn.

[0125] In a preferred embodiment of the invention, the formulation comprises, in addition to the polyoxometallate compound, one, two, three, four or more further metal complexes, preferably each of the further metal complexes containing a ligand selected from inorganic or organic ligands. Preferred inorganic ligands are halides, phosphoric acid, sulfonic acid, nitric acid and water, optionally deprotonated. Preferred organic ligands are alcohols, carboxylic acids, cyanates, isocyanates, 1,3-diketones, β-keto acids, β-keto esters, organic phosphonic acids, organic sulfonic acids, oximes, hydroxamic acids, dihydroxybenzenes, hydroxybenzoic acids, dihydroxybenzoic acids, gallic acids, dihydroxynaphthalenes, anthracene diols, hydroxy-anthrones, anthracene triols, dithranols, halogenated hydrocarbons, aromatics, heteroaromatics, esters, catechols, coumarins and derivatives thereof, optionally deprotonated.

[0126] The presence of such further metal complexes makes it possible to tailor certain properties of the optical metal oxide layers prepared therefrom, such as material hardness, shrinkage, refractive index, transparency, absorbance, and haze suppression.

[0127] Preferably, the mass w / w ratio between the polyoxometallate compound and the one or more further metal complexes in the formulation is in the range of 1:100 to 100:1, preferably 1:10 to 10:1, more preferably 1:5 to 5:1.

[0128] The total content of polyoxometalate compound and further metal complex contained in the formulation is preferably in the range of 0.1 w / w% to 50 w / w%, preferably 0.5 w / w% to 40 w / w%, more preferably 1 w / w% to 30 w / w%, based on the total mass of the formulation.

[0129] In a preferred embodiment of the invention, the formulation is an ink formulation suitable for inkjet printing. Typical requirements for an ink formulation are a surface tension in the range of 20 mN / m to 30 mN / m, and a viscosity in the range of 5 MPa·s to 10 MPa·s.

[0130] Method for preparing optical metal oxide layers The present invention relates to a method for preparing an optical metal oxide layer, the method comprising the following steps (a) to (c): (a) providing a formulation according to the present invention; (b) applying the formulation to a surface of a substrate; (c) converting the formulation into an optical metal oxide layer on a surface of the substrate.

[0131] In a preferred embodiment of the present invention, the formulation provided in step (a) of the method for preparing an optical metal oxide layer is an ink formulation suitable for inkjet printing. Typical requirements for an ink formulation are a surface tension in the range of 20 mN / m to 30 mN / m and a viscosity in the range of 5 MPa·s to 10 MPa·s.

[0132] In a preferred embodiment of the method for preparing an optical metal oxide layer according to the present invention, the formulation is applied to the surface of the substrate in step (b) by a deposition method. Preferred deposition methods are drop casting, coating or printing. More preferred coating methods are spin coating, spray coating, slit coating or slot die coating. More preferred printing methods are flexographic printing, gravure printing, inkjet printing, EHD printing, offset printing or screen printing. Most preferred are spray coating and inkjet printing.

[0133] Depending on the particular problem to be solved, the formulation needs to be deposited as a homogeneous, dense thin layer covering the entire surface of the substrate by a coating method, or the formulation needs to be deposited locally in a structured manner, hence a printing method. Both coating and printing methods require the formulation to be formulated in an appropriate manner to suit the physicochemical needs of the respective coating and printing method, as well as the specific needs regarding the surface of the substrate to be coated or printed.

[0134] In a preferred embodiment of the method for producing an optical metal oxide layer according to the invention, the surface of the substrate is pretreated by a surface cleaning process. A preferred surface cleaning process is the silicon wafer cleaning process described in W. Kern, The Evolution of Silicon Wafer Cleaning Technology, J. Electrochem. Soc., Vol. 137, 6, 1990, 1887-1892, and New Process Technologies for Microelectronics, RCA Review 1970, 31, 2, 185-454. Such silicon wafer cleaning processes include wet cleaning processes with cleaning solvents (e.g., isopropanol (IPA)); wet etching processes with hydrogen peroxide solutions (e.g., piranha solution, SC1, and SC2), choline solutions, or HF solutions; dry etching processes with chemical vapor etching, UV / ozone treatment, or glow discharge techniques (e.g., O2 plasma etching); and mechanical processes with brush scrubbing, fluid jets, or ultrasonic techniques (sonification). The surface of the substrate can also be pretreated by silanization or atomic layer deposition (ALD) processes. Pretreatment of the surface of the substrate serves to modify the hydrophobicity / hydrophilicity of the surface, which can improve the adhesion and packing properties of the light metal oxide layer to the substrate surface.

[0135] In more preferred embodiments, a wet cleaning process involving a cleaning solvent (e.g., isopropanol (IPA)) is combined with one or more of the following: a wet etching process involving a hydrogen peroxide solution (e.g., piranha solution, SC1, and SC2), a choline solution, or an HF solution; a dry etching process involving chemical vapor etching, UV / ozone treatment, or glow discharge techniques (e.g., O2 plasma etching); and a mechanical process involving brush scrubbing, fluid jets, or ultrasonic techniques (sonification).

[0136] In a most preferred embodiment, a wet cleaning process involving a cleaning solvent (e.g., isopropanol (IPA)) is combined with a mechanical process involving brush scrubbing, fluid jets or ultrasonic techniques (sonification), and a wet etching process involving a hydrogen peroxide solution (e.g., piranha solution, SC1, and SC2), a choline solution, or an HF solution. In a preferred embodiment of the present invention, step (b) of the method for preparing an optical metal oxide layer is carried out several times in succession, preferably 2 to 20 times, more preferably 2 to 10 times, most preferably 2, 3, 4 or 5 times.

[0137] In a preferred embodiment of the method for preparing an optical metal oxide layer according to the invention, the formulation is converted in step (c) on the surface of the substrate into an optical metal oxide layer by exposure to a thermal and / or radiation treatment.

[0138] A preferred heat treatment involves exposure to high temperatures of up to 1200° C., preferably up to 600° C., more preferably up to 550° C., and most preferably up to 500° C. The heat treatment is not limited to any particular heat treatment method or time. Depending on the type of substrate and formulation, a person skilled in the art can determine the appropriate heat treatment method and time.

[0139] Preferred irradiation treatments include exposure to infrared (IR) light, visible (Vis) light and / or ultraviolet (UV) light. IR light has a wavelength of more than 800 nm. Vis light has a wavelength of 400-800 nm. UV light has a wavelength of less than 400 nm and may include EUV (extreme UV). The irradiation treatment is not limited to any particular irradiation treatment method or time. Depending on the type of substrate and formulation, a person skilled in the art can determine the appropriate irradiation treatment method and time.

[0140] In a more preferred embodiment of the method for preparing an optical metal oxide layer according to the present invention, the formulation is converted into an optical metal oxide layer on the surface of the substrate in step (c) by pre-firing (soft firing) at a temperature between 40 and 150°C, preferably between 50 and 120°C, more preferably between 60 and 100°C, and then firing (hard firing, sintering or annealing) at a temperature between 150 and 600°C, preferably between 250 and 550°C, more preferably between 300 and 500°C.

[0141] Pre-baking (soft bake) serves the purpose of removing volatile and low boiling components, such as, for example, volatile and low boiling compounding media or additives, from the drop-cast, coated or printed film. Pre-baking is preferably carried out for 1 to 10 minutes. After pre-baking, a layer of substrate-adherent film of metal oxide precursor or metal oxide precursor mixture is obtained. The film may further contain residual compounding media or additives.

[0142] In an alternative more preferred embodiment of the method for preparing an optical metal oxide layer according to the present invention, pre-firing can be omitted, so that the formulation is directly converted into an optical metal oxide layer on the surface of the substrate by firing (hard firing, sintering or annealing) in step (c) at temperatures between 150 and 600°C, preferably between 250 and 550°C, more preferably between 300 and 500°C.

[0143] The calcination (hard calcination, sintering or annealing) serves the purpose of converting the metal oxide precursor or metal oxide precursor mixture layer on the substrate into a metal oxide layer. The calcination process may also adjust the properties of the final metal oxide layer. The calcination is preferably carried out for 1-300 minutes, preferably 1-60 minutes, to achieve a refractive index (RI) of more than 2.0.

[0144] Pre-baking and calcining may be carried out under ambient atmosphere or under an atmosphere with increased oxygen content to decompose undesirable organic components, which may result in a lower activation energy when the metal oxide layer is formed.

[0145] In a preferred embodiment of the method of preparing an optical metal oxide layer according to the present invention, the substrate is a patterned substrate comprising topographical features, and the metal oxide forms a coating layer that covers the surface of the substrate and fills the topographical features, such that the topographical features are filled and planarized by the metal oxide.

[0146] Preferred topographical features include, for example, gaps, grooves, trenches and vias. The topographical features may be distributed uniformly or non-uniformly across the surface of the substrate. Preferably, they are arranged as an array or grid on the surface of the substrate. The topographical features preferably have different lengths, widths, diameters and different aspect ratios. The topographical features preferably have an aspect ratio of 1:20 to 20:1, more preferably 1:10 to 10:1. The aspect ratio is defined as the width of the structure relative to the height (or depth) of the structure. In terms of dimensions, the depth of the topographical features is preferably in the range of 10 nm to 10 μm, more preferably 50 nm to 5 μm, and most preferably 100 nm to 1 μm.

[0147] It is also preferred that the topographical features are inclined at a particular angle, such as an angle of 10 to 80°, preferably 20 to 60°, more preferably 30 to 50°, and most preferably about 40°. Such inclined topographical features are also referred to as inclined or blazed topographical features.

[0148] It may be necessary to locally fill a topographical feature completely or to a certain level with an optical metal oxide layer, but not cover adjacent surfaces of the substrate where the topographical feature is not available to be filled.

[0149] Thus, the method for preparing an optical metal oxide layer according to the present invention comprises the following step (d): It is preferred that the method further comprises (d) removing a portion of the optical metal oxide layer overlying the topographical feature, thereby obtaining a filled topographical feature, wherein the overburden of the optical metal oxide layer on top of the topographical feature is preferably reduced to an overburden of between 0-100 nm, more preferably 0-50, and most preferably 0-20 nm.

[0150] Step (d) is performed after steps (a)-(c) of the method according to the invention. Preferably, removing the part of the light metal oxide layer covering the top of the topography in step (d) is performed by using a surface cleaning process as described above. A preferred surface cleaning process is the silicon wafer cleaning process described in W. Kern, The Evolution of Silicon Wafer Cleaning Technology, J. Electrochem. Soc., Vol. 137, 6, 1990, 1887-1892, and New Process Technologies for Microelectronics, RCA Review 1970, 31, 2, 185-454. Such silicon wafer cleaning processes include wet etching processes with hydrogen peroxide solutions (e.g., piranha solution, SC1, and SC2), choline solutions, or HF solutions; dry etching processes with chemical vapor etching, UV / ozone treatment, or glow discharge techniques (e.g., O2 plasma etching); and mechanical processes with brush scrubbing, fluid jets, or ultrasonic techniques.

[0151] The substrate is preferably a substrate of an optical device. The preferred substrate is made of an inorganic or organic based material, preferably an inorganic based material. The preferred inorganic based material includes a material selected from the list consisting of ceramic, glass, fused silica, sapphire, silicon, silicon nitride, quartz, and transparent polymer or resin. The shape of the substrate is not particularly limited, but is preferably a sheet or wafer.

[0152] In step (b) of the method for preparing an optical metal oxide layer, the formulation is applied onto a surface of a substrate, which may be either the surface of a base material of the substrate or the surface of a layer of a material different from the base material of the substrate, such layer being formed prior to applying the formulation.

[0153] In this way, a sequence of different layers (layer stacks) can be formed on top of one another. Such layer stacks may be structured, such structures typically having nanometer scale dimensions at least in terms of diameter, width and / or aspect ratio.

[0154] Optical Devices Finally, the present invention relates to an optical device comprising an optical metal oxide layer obtainable or obtained by the method for preparing an optical metal oxide layer according to the invention described above, the optical device being preferably an augmented reality (AR) and / or virtual reality (VR) device.

[0155] Finally, the present invention further relates to an optical device comprising an optical metal oxide layer, prepared by using the formulation according to the present invention as described above. The optical device is preferably an augmented reality (AR) and / or virtual reality (VR) device.

[0156] The present invention is further illustrated by the following non-limiting examples. Those skilled in the art will recognize that various modifications, additions and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims. EXAMPLES

[0157] Analysis and Measurement Methods Ellipsometry was used to determine the layer thickness, refractive index (n) and absorptivity (k) of the metal oxide layers. The measurements were performed using an Ellipsometer M2000 from JA Woolam and three different angles of incidence (65°, 70° and 75°). The measurement data was analyzed using the software CompleteEase from JA Woolam, assuming either a complete or near complete transparent behavior above a wavelength of 600 nm, and applying B-spline fitting to obtain the refractive index (n) and absorptivity (k). The optical constants were averaged from three to four measured samples, each of which provided different layer thicknesses either after soft baking, or after hard baking, or after a combination of soft baking and subsequent hard baking.

[0158] The optical spectra of any sheet and substrate coated or uncoated with the metal oxide layer described in this invention were recorded using an Agilent UV / Vis / NIR spectrophotometer Cary7000 with UMA setup. The measurements were performed using dual beam mode, a scan speed of 600 nm / min and a spectral bandwidth of 4 nm, unpolarized light, applying a spectral window of 350 nm to 700 nm. The transmittance measurements were performed at an incidence angle of 6° to the surface normal of the sample. The detector was aligned at 180° to the light incidence. The reflectance measurements were performed at an incidence angle of 6° to the surface normal of the sample, the detector angle was 12° to the light incidence. The absorption of the sample was calculated using Equation 1, where A represents the absorption of the coated sample, R represents the reflection, and T represents the transmission of the sample.

[0159] A=1-(R+T) Equation 1 Thermogravimetric analysis was performed on a TA Instruments TGA Q50. In the normal measurement mode, the samples were heated to 950° C. in air by applying a heating gradient of 20 K / min.

[0160] The results of the elemental analyses were received as a service from an analytical service provider who performed the measurements according to DIN 51732:2014-07.

[0161] NMR measurement 1 H-NMR was measured using a 500 MHz spectrometer from Bruker Biospin GmbH.

[0162] ICP-OES metal analysis was performed on a Spectro Arcos SOP FHS12 system after chemical pulping of the analytes submitted for analysis.

[0163] FTIR spectra were recorded on a Bruker Vertex70 in ATR mode, typically ranging from 4000 to 400 cm -1 A spectral window of 0.01 mm is applied, and the spectral resolution is 2 cm. -1 It was.

[0164] SEM images were recorded using either a Tescan Mira3LMU, or a Carl Zeiss Sigma300VP, or a Carl Zeiss Supra35.

[0165] MALDI-TOF-MS spectra were recorded on a Bruker Datonics Ultraflextreme applying the positive ion mode, thus [M+H] + ions and analogs (adducts with sodium, potassium, ions, including loss of water due to internal rearrangements) were detected. In MALDI-MS, mainly singly charged ions are produced (z=1). The spectra shown were recorded in reflector mode to achieve isotopic resolution. The SmartBeam 2 laser (IR) operates at a frequency of 1000 Hz. In general, analytes were dissolved in THF (when applicable) on a 10 mg / mL scale and 0.5 μL droplets were prepared on a ground steel target. DCTB (trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene]malononitrile) was used as the MALDI matrix.

[0166] Substrate coating, usually a wafer, was carried out using a spin coater (LabSpin150i) manufactured by Suess. The spin coating process with planar substrates was as follows: 0.5 mL of coating was deposited on a stationary quartz wafer, followed by a 30 s spin interval at a given spin speed, and an acceleration to reach the final spin speed of 500 rpm / s. 2 The temperature was set at 100° C. Different layer and coating thicknesses were achieved using either different spin speeds or different coating formulations with different concentrations of metal oxide precursors or mixtures of different metal oxide precursors. After spin coating, the coated substrate was subjected to a pre-bake at 100° C. for 2 minutes to remove solvent residues, followed by baking at high temperature, or the layer deposited on the wafer was directly baked at high temperature for a specific time. Typically, but not limited to, the coated layer was baked at 300° C., 400° C. and 500° C. for 5 minutes and 60 minutes, as shown in some of the following examples. The pre-bake and layer bake were performed using a high temperature hot plate manufactured by Harry Gestigkeit, which allows reaching temperatures of up to 600° C. The aforementioned conditions and parameters apply to all the following experimental examples, unless other conditions are explicitly mentioned elsewhere.

[0167] Typically, quartz and / or silicon wafers (both 2 inch diameter) were used throughout all coating experiments where a flat, unstructured support for the metal oxide was required (e.g., spectroscopy and ellipsometry measurements).

[0168] The structured substrate, usually a silicon wafer, was used as a square die with an edge length of 1.5 cm to 2 cm. The wafer die was cut and cleaved from a parent wafer, which typically has a diameter of 8 inches. The structure was formed by depositing SiO2 / SiN xThe dimensions of the structures (e.g., cross-sectional width and length of the trenches) were referenced to the architecture of Sematech Mask 854. Typically, but not exclusively, cross-sectional cleaves perpendicular to the trench arrays providing widths of 40 nm to 50 nm were used as trench structures of primary interest to study their filling behavior with wet-chemically coated metal oxide precursors and / or metal oxides received upon thermal conversion of the metal oxide precursors. In addition to the above, cross-sections of arrays of trenches with widths of 100 nm and 150 nm were also used to study trench filling with metal oxides.

[0169] The structured wafer dies were coated by spin coating unless otherwise stated. For that purpose, a volume of the coating formulation, typically 0.15 mL to 0.5 mL per die, was pipetted and cast onto the surface of the wafer. The formulation was spread onto the surface for 1 min to settle, followed by a step of dispersing and spreading the formulation over the entire surface of the wafer die at 500 rpm for 30 s, followed by a final spin-off step at 2,000 rpm for another 60 s. The acceleration of the spin speed was 500 rpm / s 2 The soft bake and hard bake conditions for the structured wafer die were selected similar or identical to those already described for the flat substrate.

[0170] All chemicals for the syntheses described were purchased from Sigma Aldrich and used without further purification unless otherwise stated.

[0171] Part A. Single-metal polyoxometalates Example 1 Tetramethylammonium decaniobate [(NMe4)6Nb 10 O 28 * Synthesis of 6H2O The reaction apparatus, consisting of a three-necked reaction flask equipped with a reflux condenser, a glass thermometer, and a magnetic stir bar, was thoroughly flushed with a constant flow of Ar. A conventional magnetic lab hotplate was used as the heating source, as was a magnetically coupled stirrer. All steps described below were performed with constant stirring of the reaction mixture. 689.743 g of ethanol was added to the reaction flask, and 87.793 g (0.276 mol) of niobium ethoxide was dissolved in the solvent. 50 g (0.276 mol) of tetramethylammonium hydroxide pentahydrate was slowly added to the solution. The temperature of the reaction mixture was increased to 90° C., and the mixture was allowed to react overnight. During the reaction, the solution turned into a suspension. After cooling the reaction mixture, the precipitate was collected by filtration and washed with EtOH to obtain a white powder, which was dried at room temperature using a vacuum oven. The product was subjected to elemental analysis, ICP-OES analysis, and TG analysis. TG analysis gave a residual mass of 70.24 w / w%, which was found to be in excellent agreement with the expected value of 68.86 w / w%. Elemental analysis of the product provided 15.2 w / w% (14.94 w / w%) for C, 4.4 w / w% (4.39 w / w%) for H, and 4.5 w / w% (4.35 w / w%) for N, with theoretically expected values ​​provided as values ​​in brackets. The niobium content was found to be 46.0 w / w% (48.14 w / w%).

[0172] Example 2 Synthesis of tetrabutylammonium polyniobate The reaction apparatus, consisting of a three-necked reaction flask equipped with a reflux condenser, a glass thermometer, and a magnetic stirring bar, was thoroughly flushed with a constant flow of Ar. A conventional magnetic lab hotplate was used as the heating source, as was a magnetically coupled stirrer. All steps described below were performed with constant stirring of the reaction mixture. 59.25 g of ethanol was added to the reaction flask, and 9.456 g (0.030 mol) of niobium ethoxide was dissolved in the solvent. 7.784 g (0.010 mol) of tetrabutylammonium hydroxide (TBAH) was added. *30 H2O) was slowly added in portions to the solution. The temperature of the reaction mixture was raised to 90°C and the mixture was allowed to react overnight. After cooling the reaction mixture, the solvent was evaporated using a rotary evaporator to obtain a yellow syrupy honey-like residue. The crude product was subjected to elemental analysis, ICP-OES analysis, and TG analysis. TG analysis gave a residual mass of 52.42 w / w%. Elemental analysis of the product provided 32.9 w / w% for C and 7.2 w / w% for H. The content of niobium was found to be 35.0 w / w%.

[0173] The product was further subjected to MALDI-MS analysis (see FIG. 7). The peak at m / z 2831.56 Da was determined to be hexakis(tetrabutylammonium) decanioate [C 96 H 216 NO 28 Nb 10 ] + The peak at m / z 2590.29 Da indicates the loss of a tetrabutylammonium ligand and thus the ion [C 80 H 180 N5O 28 Nb 10 ] + The same is assumed to be true for the peak at m / z 2493.14 Da, which corresponds to the cluster ion at m / z 2734.41 Da minus one tetrabutylammonium ligand.

[0174] Example 3 The product obtained in Example 1 was dissolved in a solution consisting of 1-methoxy-2-propanol (60 w / w%) and water (40 w / w%) to obtain a solution with a product concentration of 20 w / w%. Coating was performed on quartz wafers according to the procedure described in the general experimental section above. The coating speed ranged from 1,500 rpm to 2,500 rpm with intervals of 500 rpm. After coating, the wafers were directly baked at 300°C, 400°C and 500°C for 5 and 60 minutes, respectively. The layer thicknesses and refractive indices of the coated and baked layers were determined by ellipsometry (see Table 1).

[0175] [Table 1]

[0176] Example 4 The product obtained in Example 2 was dissolved in 1-methoxy-2-propanol to obtain a solution with a formula concentration of 20 w / w%. Coating was performed on quartz wafers according to the procedure described in the general experimental section above. The coating speed ranged from 1,500 rpm to 2,500 rpm with intervals of 500 rpm. After coating, the wafers were directly baked at 300°C, 400°C and 500°C for 5 and 60 minutes, respectively. The layer thickness, refractive index and absorptivity of the coated and baked layers were determined by ellipsometry (see Table 2 and Figure 8).

[0177] [Table 2]

[0178] Example 5 The product obtained in Example 2 was dissolved in 1-methoxy-2-propanol to obtain a solution with a formula concentration of 20 w / w%. Square silicon wafer dies with edge lengths of 1.5 cm to 2.5 cm were used as substrates and coated with the aforementioned mixture. Each die contained arrays of different structures, mainly trenches with different opening widths, and each array had a square footprint with an edge length of about 0.5 cm. The trenches had a constant depth and their pitch varied according to the trench opening width (see FIG. 9). The arrays were aligned so that the trenches were either parallel or perpendicular to each other. 0.5 mL of the coating mixture was deposited on the die and allowed to diffuse for about 1 minute, after which the die was coated at 500 rpm for 30 seconds and at 2,000 rpm for another 30 seconds. The die was then pre-baked at 60° C. for 60 minutes to remove residual solvent. As a next step, the die was baked at 200° C. for 5 minutes. After cleaving the trench array perpendicular to the extension direction of the trenches, the coated die was subjected to SEM cross-section analysis. The cleaved part was coated with a 2 nm thick Pt layer by sputtering. From the SEM cross-section, it can be seen that the trenches were almost completely filled after pre-baking at 60°C (see Figure 10). After baking at 200°C (see Figure 11), the trenches were still filled by the coated and baked metal oxide material.

[0179] Example 6 Tetrabutylammonium polyniobate + lanthanum methoxyethoxide The product obtained in Example 2 was dissolved in 1-methoxy-2-propanol to obtain a solution with a formula concentration of 20 w / w%. To 4.020 g of this solution, 2.28 g of lanthanum methoxyethoxide in methoxyethanol (supplier: abcr), 3.69 g of 1-methoxy-2-propanol and 1 g of glacial acetic acid were added and thoroughly stirred to obtain an oxide mixture with a nominal oxide content of 81.3 n / n% Nb2O5 and 17.7 n / n% La2O3. Coating was performed on quartz wafers according to the procedure described in the general experimental section above. The coating speed ranged from 1,500 rpm to 2,500 rpm with an interval of 500 rpm. After coating, the wafers were directly baked at 300°C, 400°C and 500°C for 5 and 60 minutes, respectively. The layer thickness, refractive index and absorptivity of the coated and baked layers were determined by ellipsometry (see Table 3 and Figure 12).

[0180] [Table 3]

[0181] Example 7 Tetrabutylammonium polyniobate + lanthanum methoxyethoxide The product obtained in Example 2 was dissolved in 1-methoxy-2-propanol to obtain a solution with a formula concentration of 20 w / w%. To 4.826 g of this solution, 1.173 g of lanthanum methoxyethoxide in methoxyethanol (supplier: abcr), 4 g of 1-methoxy-2-propanol and 1.5 g of glacial acetic acid were added and thoroughly stirred to obtain an oxide mixture with a nominal oxide content of 91.6 n / n% Nb2O5 and 8.4 n / n% La2O3. Coating was performed on quartz wafers according to the procedure described in the general experimental section above. The coating speed ranged from 1,500 rpm to 2,500 rpm with an interval of 500 rpm. After coating, the wafers were directly baked at 300°C, 400°C and 500°C for 5 and 60 minutes, respectively. The layer thickness, refractive index and absorptivity of the coated and baked layers were determined by ellipsometry (see Table 4 and Figure 13).

[0182] [Table 4]

[0183] Example 8 Synthesis of tetrabutylammonium polytantalate The reaction apparatus, consisting of a three-necked reaction flask equipped with a reflux condenser, a glass thermometer, and a magnetic stirring bar, was thoroughly flushed with a constant flow of Ar. A conventional magnetic lab hotplate was used as the heating source, as was a magnetically coupled stirrer. All steps described below were carried out with constant stirring of the reaction mixture. 706.16 g of acetonitrile was added to the reaction flask, and 9.581 g (0.012 mol) of tetrabutylammonium hydroxide (TBAH * 30 H2O) and 2.661 g water were dissolved in the solvent. 15 g (0.037 mol) tantalum ethoxide was added dropwise to the solution and the mixture was stirred overnight. After filtration through a 1 μm filter, the solvent was evaporated using a rotary evaporator to obtain a syrupy honey-like residue. A small amount of resin was collected and subjected to further analysis, e.g., elemental analysis. Elemental analysis of the product provided 23.2 w / w% for C, 4.7 w / w% for H, and 3.2 w / w% for N. The tantalum content was found to be 51 w / w%. The main fraction was dissolved in 1-methoxy-2-propanol to obtain a solution with a nominal concentration of 50 w / w%. Upon dissolution, the mixture became slightly turbid. In the crude product, the still remaining nanoscale particles were removed by centrifugation and the dispersion was processed twice for 60 minutes each at a rotation speed of 6,000 rpm. The supernatant was used either for further analysis or for application experiments. TG analysis of the solution yielded a residual mass of 36.72 w / w% and therefore 18.36 w / w% Ta2O5 under the assumption of complete combustion and conversion of the polytantalates in air.

[0184] The solution was further subjected to MALDI-MS analysis (see FIG. 14). The peak at m / z 3710.9 Da was determined to be hexakis(tetrabutylammonium) decatantalate [C 96 H216 NO 28 Ta 10 ] + The peaks at m / z 3952.1 Da and 3469.9 Da may represent either the addition or removal of tetrabutylammonium ligands, and thus, [C 112 H 252 N7O 28 Ta 10 ] + Or [C 80 H 180 N5O 28 Ta 10 ] + It is.

[0185] Example 9 The product obtained in Example 8 was dissolved in 1-methoxy-2-propanol to obtain a solution with a formula concentration of 20 w / w%. Coating was performed on quartz wafers according to the procedure described in the general experimental section above. The coating speed ranged from 1,000 rpm to 2,500 rpm with intervals of 500 rpm. After coating, the wafers were directly baked at 300°C, 400°C and 500°C, respectively, for 60 min. The layer thicknesses and refractive indices of the coated and baked layers were determined by ellipsometry (see Table 5).

[0186] [Table 5]

[0187] Example 10 The product obtained in Example 8 was dissolved in 1-methoxy-2-propanol to obtain a solution with a formula concentration of 20 w / w%. A wafer die containing the structure already described in Example 5 was used for coating. The coating conditions and substrate preparation were identical to those already described in Example 5. The layer was pre-baked at 60° C. for 60 minutes, followed by baking at 200° C. for 5 minutes, including a temperature ramping step between the pre-baking and baking plateau temperatures. The temperature ramping from 60° C. to 200° C. was performed for 20 minutes, thus providing a nominal heating rate of 7 K / min. From the SEM cross section it can be seen that the trench was almost completely filled after the pre-baking performed at 60° C. (see FIG. 15). After the temperature ramping from the pre-baking to the baking temperature of 200° C. (see FIG. 16), the trench was still partially filled by the coated and baked metal oxide material.

[0188] Part B. Bimetallic polyoxometalates (mixed metal centers) Example 11 Synthesis of mixed tetrabutylammonium poly(niobate-tantalate) with a nominal composition of 50n / n% Nb2O5 and 50n / n% Ta2O5. The reaction apparatus, consisting of a three-necked reaction flask equipped with a reflux condenser, a glass thermometer, and a magnetic stirring bar, was thoroughly flushed with a constant flow of Ar. A conventional magnetic lab hotplate was used as the heating source, as was a magnetically coupled stirrer. All steps described below were carried out with constant stirring of the reaction mixture. 29.625 g of ethanol was added to the reaction flask, followed by 4.773 g (0.015 mol) of niobium ethoxide and 6.094 g (0.015 mol) of tantalum ethoxide. Subsequently, tetrabutylammonium hydroxide (TBAH) was added to the flask, and 4.773 g (0.015 mol) of niobium ethoxide and 6.094 g (0.015 mol) of tantalum ethoxide were added to it. *7.784 g (0.010 mol) of 1,2-dichlorobenzene (COOH) was added to the mixture. The mixture was refluxed overnight with stirring. The solvent was then evaporated using a rotary evaporator to give a syrupy honey-like highly viscous residue. A small fraction of the resin was collected and subjected to analysis, e.g., elemental analysis and thermogravimetric analysis. Elemental analysis of the product provided 24.2 w / w% for C, 5.2 w / w% for H, and 1.6 w / w% for N. The niobium content was 16 w / w% and the tantalum content was 30 w / w% (both by ICP-OES). TG analysis gave a residual mass of 63.24 w / w%.

[0189] Further analysis by MALDI-MS (see FIG. 17) gave the data shown in Table 6.

[0190] [Table 6]

[0191] Example 12 The product obtained in Example 11 was dissolved in 1-methoxy-2-propanol to obtain a solution with a formula concentration of 20 w / w%. Coating was performed on quartz wafers according to the procedure described in the general experimental section above. The coating speed ranged from 1,000 rpm to 3,000 rpm with intervals of 1,000 rpm. After coating, the wafers were directly baked at 300°C, 400°C and 500°C for 5 and 60 minutes, respectively. The layer thicknesses and refractive indices of the coated and baked layers were determined by ellipsometry (see Table 7).

[0192] [Table 7]

[0193] Example 13 Synthesis of mixed tetrabutylammonium poly(niobate-titanate) with a nominal composition of 71n / n% Nb2O5 and 29n / n% TiO2 and a metal ion to base ratio of 3:1 The reactor, consisting of a three-necked reaction flask equipped with a reflux condenser, a glass thermometer, and a magnetic stir bar, was thoroughly flushed with a constant flow of Ar. A conventional magnetic lab hotplate was used as the heating source, as was a magnetically coupled stirrer. All steps described below were carried out with constant stirring of the reaction mixture. 95.16 g of ethanol was added to the reaction flask, followed by 15.090 g (0.047 mol) of niobium ethoxide and 2.800 g (0.0099 mol) of titanium isopropoxide. Subsequently, tetrabutylammonium hydroxide (TBAH) was added to the flask, and 15.090 g (0.047 mol) of niobium ethoxide and 2.800 g (0.0099 mol) of titanium isopropoxide were added to it. * 15.070 g (0.019 mol) of 1,2-dichloro-30H2O was added to the mixture. The mixture was refluxed overnight with stirring. The solvent was then evaporated using a rotary evaporator to give a slightly foamy, creamy yellowish solid residue. The residue was subjected to thermogravimetric and elemental analysis. Elemental analysis of the product provided 33.8 w / w% for C, 6.7 w / w% for H, and 2.0 w / w% for N. The niobium content was 30 w / w% and the titanium content was 3.3 w / w% (both by ICP-OES). TG analysis gave a residual mass of 51.30 w / w%.

[0194] Further analysis was provided by MALDI-MS (see Figures 18 and 19).

[0195] Figure 18: The peak at m / z 2830 Da corresponds to the cluster ion [C 96 H 216 NO 28 Nb 10 ] + From the isotopic pattern of the peak at m / z 2646 Da, it can be concluded that the species or cluster ion contains Ti.

[0196] Figure 19: The same is true for the peaks at m / z 3071 Da and 3127 Da. Both peaks show an isotopic pattern indicating the presence of Ti in the cluster ions. The peak above m / z 2900 Da specifically refers to titanium-containing cluster ions. Very prominent cluster ions of this type, showing the typical isotopic pattern of titanium-containing ions, can be found at positions m / z 3071 Da and 3127 Da. The cluster ion at m / z 3027 Da indicates that one of the niobium metal centers has been replaced by titanium, and therefore the following cluster ion: [C 112 H 252 N7O 28 Nb9Ti] + This seems to refer to cluster ions that form

[0197] Example 14 The product obtained in Example 13 was dissolved in 1-methoxy-2-propanol to obtain a solution with a formula concentration of 20 w / w%. Coating was performed on quartz wafers according to the procedure described in the general experimental section above. The coating speed ranged from 1,000 rpm to 3,000 rpm with intervals of 1,000 rpm. After coating, the wafers were directly baked at 300°C, 400°C and 500°C, respectively, for 5 minutes. The layer thicknesses and refractive indices of the coated and baked layers were determined by ellipsometry (see Table 8).

[0198] [Table 8]

[0199] Example 15 Synthesis of mixed tetrabutylammonium poly(niobate-titanate) with a nominal composition of 71n / n% Nb2O5 and 29n / n% TiO2 and a metal ion to base ratio of 1.6:1 The reaction apparatus, consisting of a three-necked reaction flask equipped with a reflux condenser, a glass thermometer, and a magnetic stirring bar, was thoroughly flushed with a constant flow of Ar. A conventional magnetic lab hotplate was used as the heating source, as was a magnetically coupled stirrer. All steps described below were carried out with constant stirring of the reaction mixture. 95.16 g of ethanol was added to the reaction flask, followed by 15.15 g (0.048 mol) of niobium ethoxide and 2.800 g (0.0099 mol) of titanium isopropoxide. Subsequently, tetrabutylammonium hydroxide (TBAH) was added to the flask, and 10.0 g (0.01 mol) of niobium ethoxide was added to the flask. * 29.32 g (0.037 mol) of 1,2-dichloro-30H2O was added to the mixture. The mixture was refluxed overnight with stirring. The solvent was then evaporated using a rotary evaporator to obtain a creamy yellowish resin of moderate viscosity. The residue was subjected to thermogravimetric and elemental analysis. Elemental analysis of the product provided 42.5 w / w% for C, 8.4 w / w% for H, and 2.8 w / w% for N. The niobium content was 24 w / w% and the titanium content was 2.6 w / w% (both by ICP-OES).

[0200] Example 16 The product obtained in Example 15 was dissolved in 1-methoxy-2-propanol to obtain a solution with a formula concentration of 20 w / w%. Coating was performed on quartz wafers according to the procedure described in the general experimental section above. The coating speed ranged from 1,000 rpm to 3,000 rpm with intervals of 1,000 rpm. After coating, the wafers were directly baked at 300°C, 400°C and 500°C, respectively, for 5 minutes. The layer thicknesses and refractive indices of the coated and baked layers were determined by ellipsometry (see Table 9).

[0201] [Table 9]

[0202] Example 17 Synthesis of mixed tetrabutylammonium poly(niobate-vanadate) with a nominal composition of 81n / n% Nb2O5 and 19n / n% V2O5 The reaction apparatus, consisting of a three-necked reaction flask equipped with a reflux condenser, a glass thermometer, and a magnetic stirring bar, was thoroughly flushed with a constant flow of Ar. A conventional magnetic lab hotplate was used as the heating source, as was a magnetically coupled stirrer. All steps described below were carried out with constant stirring of the reaction mixture. 93.95 g of ethanol was added to the reaction flask, followed by 15.19 g (0.048 mol) of niobium ethoxide and 5.81 g (0.011 mol) of vanadyl triisopropylate. Subsequently, tetrabutylammonium hydroxide (TBAH) was added to the flask, and 10.0 g (0.011 mol) of vanadyl triisopropylate was added to it. * 14.72 g (0.037 mol) of 1,2-dichloro-30H2O was added to the mixture. The mixture was refluxed overnight with stirring. The solvent was then evaporated using a rotary evaporator to give a thick dark green slightly foamy residue. The residue was subjected to thermogravimetric and elemental analysis. Elemental analysis of the product provided 32.6 w / w% for C, 6.4 w / w% for H, and 1.8 w / w% for N. The niobium content was 27 w / w% and the titanium content was 7.4 w / w% (both by ICP-OES). TG analysis gave a residual mass of 43.53 w / w%.

[0203] Further analysis by MALDI-MS (see FIG. 20) gave the data shown in Table 10.

[0204] [Table 10]

[0205] Example 18 The product obtained in Example 17 was dissolved in 1-methoxy-2-propanol to obtain a solution with a formula concentration of 20 w / w%. Coating was performed on quartz wafers according to the procedure described in the general experimental section above. The coating speed ranged from 1,000 rpm to 3,000 rpm with intervals of 1,000 rpm. After coating, the wafers were directly baked at 300°C, 400°C and 500°C, respectively, for 5 minutes. The layer thicknesses and refractive indices of the coated and baked layers were determined by ellipsometry (see Table 11).

[0206] [Table 11]

[0207] Example 19 Synthesis of mixed tetrabutylammonium poly(tantalate-vanadate) with a nominal composition of 75n / n% Ta2O5 and 25n / n% V2O5 The reaction apparatus, consisting of a three-necked reaction flask equipped with a reflux condenser, a glass thermometer, and a magnetic stir bar, was thoroughly flushed with a constant flow of Ar. A conventional magnetic lab hotplate was used as the heating source, as was a magnetically coupled stirrer. All steps described below were carried out with constant stirring of the reaction mixture. 706.161 g of acetonitrile was added to the reaction flask, and 29.916 g (0.037 mol) of tetrabutylammonium hydroxide (TBAH *30 H2O) and 8.308 g water were added and dissolved. Subsequently, 35.13 g (0.086 mol) of tantalum ethoxide and 7.039 g (0.029 mol) of vanadyl triisopropylate were added in a dropwise manner. After the addition was completed, the mixture was stirred overnight. The reaction mixture was filtered through a 1 μm filter, and the solvent was evaporated on a rotary evaporator. A small amount of resin was collected and subjected to thermogravimetric analysis, which gave a residual mass of 63.74 w / w%. The main fraction was dissolved in 1-methoxy-2-propanol to give a solution with a nominal concentration of 50 w / w%. Upon dissolution, the mixture became slightly turbid. In the crude product, the still remaining nanoscale particles were removed by centrifugation, and the dispersion was processed twice for 60 minutes each at a rotation speed of 6,000 rpm. The supernatant was used for the application experiments.

[0208] Example 20 The product obtained in Example 19 was further diluted with n-butanol to obtain a solution with a formula concentration of 20 w / w%. Coating was performed on quartz wafers according to the procedure described in the general experimental section above. The coating speed ranged from 1,000 rpm to 3,000 rpm with intervals of 1,000 rpm. After coating, the wafers were directly baked at 300°C, 400°C and 500°C, respectively, for 5 minutes. The layer thicknesses and refractive indices of the coated and baked layers were determined by ellipsometry (see Table 12).

[0209] [Table 12]

[0210] Example 21 Synthesis of mixed tetrabutylammonium poly(tantalate-vanadate) with a nominal composition of 50n / n% Ta2O5 and 50n / n% V2O5 The reaction apparatus, consisting of a three-necked reaction flask equipped with a reflux condenser, a glass thermometer, and a magnetic stir bar, was thoroughly flushed with a constant flow of Ar. A conventional magnetic lab hotplate was used as the heating source, as was a magnetically coupled stirrer. All steps described below were carried out with constant stirring of the reaction mixture. 706.165 g of acetonitrile was added to the reaction flask, and 29.917 g (0.037 mol) of tetrabutylammonium hydroxide (TBAH * 30 H2O) and 8.308 g water were added and dissolved. Subsequently, 23.42 g (0.058 mol) of tantalum ethoxide and 14.078 g (0.058 mol) of vanadyl triisopropylate were added in a dropwise manner. After the addition was completed, the mixture was stirred overnight. The reaction mixture was filtered through a 1 μm filter, and the solvent was evaporated in a rotary evaporator. A small amount of resin was collected and subjected to thermogravimetric analysis, which gave a residual mass of 61.81 w / w%. The main fraction was dissolved in 1-methoxy-2-propanol to give a solution with a nominal concentration of 50 w / w%. Upon dissolution, the mixture became slightly turbid. In the crude product, the still remaining nanoscale particles were removed by centrifugation, and the dispersion was processed twice for 60 min each at a rotation speed of 6,000 rpm. The supernatant was used for the application experiments.

[0211] Example 22 The product obtained in Example 21 was further diluted with n-butanol to obtain a solution with a formula concentration of 20 w / w%. Coating was performed on quartz wafers according to the procedure described in the general experimental section above. The coating speed ranged from 1,000 rpm to 3,000 rpm with intervals of 1,000 rpm. After coating, the wafers were directly baked at 300°C, 400°C and 500°C for 5 minutes, respectively. The layer thicknesses and refractive indices of the coated and baked layers were determined by ellipsometry (see Table 13).

[0212] [Table 13]

[0213] Example 23 Synthesis of mixed tetrabutylammonium poly(tantalate-titanate) with a nominal composition of 79n / n% Ta2O5 and 21n / n% TiO2 The reaction apparatus, consisting of a three-necked reaction flask equipped with a reflux condenser, a glass thermometer, and a magnetic stirring bar, was thoroughly flushed with a constant flow of Ar. A conventional magnetic lab hotplate was used as the heating source, as was a magnetically coupled stirrer. All steps described below were carried out with constant stirring of the reaction mixture. 481.152 g of acetonitrile was added to the reaction flask, and 17.75 g (0.022 mol) of tetrabutylammonium hydroxide (TBAH * 30 H2O) and 7.923 g water were added and dissolved. Then, 25.05 g (0.062 mol) of tantalum ethoxide and 2.35 g (0.008 mol) of titanium isopropoxide were added in a dropwise manner. After the addition was completed, the mixture was stirred overnight. After filtering the reaction through a 1 μm filter, the filtrate still containing the nanoscale particles was centrifuged and treated twice for 30 min at a rotation speed of 3,700 rpm. The supernatant was rotary evaporated to remove the solvent and obtain a yellowish resin with high viscosity. The crude product was subjected to elemental analysis and thermogravimetric analysis. The latter gave a residual mass of 59.99 w / w%. Elemental analysis of the product provided 26.4 w / w% for C, 6.4 w / w% for H, and 2.4 w / w% for N. The tantalum content was 43 w / w% and the titanium content was 2 w / w% (both by ICP-OES).

[0214] Example 24 The product obtained in Example 23 was further diluted with 1-methoxy-2-propanol to obtain a solution with a formula concentration of 20 w / w%. Coating was performed on quartz wafers according to the procedure described in the general experimental section above. The coating speed ranged from 1,000 rpm to 3,000 rpm with intervals of 1,000 rpm. After coating, the wafers were directly baked at 300°C, 400°C and 500°C for 5 minutes, respectively. The layer thicknesses and refractive indices of the coated and baked layers were determined by ellipsometry (see Table 14).

[0215] [Table 14]

[0216] Example 25 Synthesis of mixed tetrabutylammonium poly(tantalate-titanate) with a nominal composition of 67n / n% Ta2O5 and 33n / n% TiO2 The reaction apparatus, consisting of a three-necked reaction flask equipped with a reflux condenser, a glass thermometer, and a magnetic stir bar, was thoroughly flushed with a constant flow of Ar. A conventional magnetic lab hotplate was used as the heating source, as was a magnetically coupled stirrer. All steps described below were carried out with constant stirring of the reaction mixture. 705.828 g of acetonitrile was added to the reaction flask, and 29.91 g (0.037 mol) of tetrabutylammonium hydroxide (TBAH * 30 H2O) and 8.3 g water were added and dissolved. Then, 24.3 g (0.060 mol) of tantalum ethoxide and 5.1 g (0.015 mol) of titanium isopropoxide were added dropwise. After the addition was completed, the mixture was stirred overnight. After filtering the reaction through a 1 μm filter, the filtrate still containing the nanoscale particles was centrifuged and treated twice for 30 min at a rotation speed of 3,700 rpm. The supernatant was rotary evaporated to remove the solvent and obtain a yellowish resin with high viscosity. The crude product was subjected to elemental analysis and thermogravimetric analysis. The latter gave a residual mass of 51.31 w / w%. Elemental analysis of the product provided 33.2 w / w% for C, 6.7 w / w% for H, and 2.6 w / w% for N. The tantalum content was 38 w / w% and the titanium content was 0.3 w / w% (both by ICP-OES).

[0217] Example 26 The product obtained in Example 23 was further diluted with 1-methoxy-2-propanol to obtain a solution with a formula concentration of 20 w / w%. Coating was performed on quartz wafers according to the procedure described in the general experimental section above. The coating speed ranged from 1,000 rpm to 3,000 rpm with intervals of 1,000 rpm. After coating, the wafers were directly baked at 300°C, 400°C and 500°C for 5 minutes, respectively. The layer thicknesses and refractive indices of the coated and baked layers were determined by ellipsometry (see Table 15).

[0218] [Table 15]

[0219] The above examples show that the technical object of the present invention is achieved. [Explanation of symbols]

[0220] 1 Materials with RI0202 2 Materials with RI0101 3 Substrate (e.g., glass) 4 Diffraction of incident light represented by the thick arrow 5 Total Internal Reflection (TIR) ​​of Light 6 Waveguide 7 Structured layer stack with gaps (trench) 8 Substrate (e.g., glass or silicon) 9 Overburden of materials (e.g., high refractive index materials or highly etch resistant materials) 10 Materials that provide gap filling (e.g., high refractive index materials or highly etch resistant materials) 11 void 12 Formulations (e.g., inks) of high refractive index materials (e.g., metal oxide precursors) 13 High refractive index materials (e.g. metal oxides) that provide gap filling with arbitrary concave shapes 14 Overburden layer (optional) 15. Energy

Claims

1. A polyoxometalate compound containing a polyoxometalate cluster, wherein the polyoxometalate cluster preferably contains two or three group 5 elements selected from V, Nb, and Ta.

2. The polyoxometalate compound according to claim 1, wherein the polyoxometalate cluster further comprises one or more Group 4 elements preferably selected from Ti, Zr, and Hf.

3. The polyoxometalate cluster is represented by formula (1) [M] １ ｘ１ M ２ ｘ２ O ｙ ] ｍ Equation (1) [In the formula, M １ This is preferably a mixture of two or three Group 5 elements selected from V, Nb, and Ta. M ２ This is preferably one group 4 element selected from Ti, Zr, and Hf, or a mixture of two or more group 4 elements. O is oxygen, x1 is an integer between 3 and 40. x² is an integer between 0 and 40. y is an integer between 8 and 160. The polyoxometalate compound according to claim 1, wherein m represents the total charge of the polyoxometalate cluster.

4. The polyoxometalate cluster is represented by formula (1) [M] １ ｘ１ M ２ ｘ２ O ｙ ] ｍ Equation (1) [In the formula, M １ This is a mixture of V and Nb, V and Ta, Nb and Ta, or V, Nb and Ta. M ２ is Ti, Zr, or Hf, O is oxygen, x1 is an integer between 3 and 40. x² is an integer between 0 and 40. x1 + x2 = 3 to 40, y is an integer between 8 and 160. m represents the total charge of the polyoxometalate cluster, where m = S1 ＊ x1 + S2 ＊ x2-2 ＊ The polyoxometalate compound according to claim 3, wherein y is y, S1 is 5, and S2 is 4.

5. Independent of each other, H ＋ Li ＋ Na ＋ _K ＋ , Rb ＋ , Cs ＋ NH ４－ａ R ａ ＋ Mg ２＋ Ca ２＋ , Sr ２＋ and Ba ２＋ It further contains one or more cations selected from, R is an organic group, A polyoxometalate compound according to any one of claims 1 to 4, wherein a is an integer from 0 to 4.

6. A formulation for preparing an optical metal oxide layer, wherein the formulation is (i) A polyoxometalate compound containing a polyoxometalate cluster, wherein the polyoxometalate cluster preferably contains one, two, or three Group V elements selected from V, Nb, and Ta, (ii) A compound containing one or more compounding media.

7. The formulation according to claim 6, wherein the polyoxometalate cluster further comprises one or more Group 4 elements preferably selected from Ti, Zr, and Hf.

8. The polyoxometalate cluster is represented by formula (1) [M] １ ｘ１ M ２ ｘ２ O ｙ ] ｍ Equation (1) [In the formula, M １ This is preferably one group 5 element selected from V, Nb, and Ta, or a mixture of two or three group 5 elements. M ２ This is preferably one group 4 element selected from Ti, Zr, and Hf, or a mixture of two or more group 4 elements. O is oxygen, x1 is an integer between 3 and 40. x² is an integer between 0 and 40. y is an integer between 8 and 160. The formulation according to claim 6, where m represents the total charge of the polyoxometalate clusters.

9. The polyoxometalate cluster is represented by formula (1) [M] １ ｘ１ M ２ ｘ２ O ｙ ] ｍ Equation (1) [In the formula, M １ This is one group 5 element selected from V, Nb, and Ta, or a mixture of two or three group 5 elements. M ２ is Ti, Zr, or Hf, O is oxygen, x1 is an integer between 3 and 40. x² is an integer between 0 and 40. x1 + x2 = 3 to 40, y is an integer between 8 and 160. m represents the total charge of the polyoxometalate cluster, where m = S1 ＊ x1 + S2 ＊ x2-2 ＊ The formulation according to claim 8, where y is, S1 is 5, and S2 is 4.

10. The polyoxometalate compounds are independently of each other, ＋ Li ＋ Na ＋ _K ＋ , Rb ＋ , Cs ＋ NH ４－ａ R ａ ＋ Mg ２＋ Ca ２＋ , Sr ２＋ and Ba ２＋ It further contains one or more cations selected from, R is an organic group, The formulation according to any one of claims 6 to 9, wherein a is an integer from 0 to 4.

11. The composition according to any one of claims 6 to 9, wherein the content of the polyoxometalate compound in the composition is in the range of 0.1 w / w% to 50 w / w% based on the total mass of the composition.

12. The formulation according to any one of claims 6 to 9, wherein one or more of the formulation media are a solution medium and / or a dispersion medium.

13. The formulation according to any one of claims 6 to 9, wherein the formulation further comprises (iii) one or more additives selected from a surfactant, a wetting dispersant, an adhesion promoter, and a polymer matrix.

14. A method for preparing an optical metal oxide layer, comprising the following steps (a) to (c): (a) To provide the formulation according to any one of claims 6 to 9, (b) Applying the above-mentioned compound to the surface of the substrate, (c) A method comprising converting the compound into an optical metal oxide layer on the surface of the substrate.

15. The method according to claim 14, wherein in step (b), the compound is applied to the surface of the substrate by a deposition method.

16. The method according to claim 14, wherein in step (c), the compound is converted into an optical metal oxide layer on the surface of the substrate by exposure to heat treatment and / or irradiation treatment.

17. The method according to claim 14, wherein in step (c), the compound is pre-fired at a temperature of 40 to 150°C and then fired at a temperature of 150 to 600°C to be converted into an optical metal oxide layer on the surface of the substrate.

18. The method according to claim 14, wherein the substrate is a patterned substrate having its topographical features on the surface.

19. An optical device comprising an optical metal oxide layer prepared by using the formulation described in any one of claims 6 to 9.

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