preparation

Abstract

This invention relates to a formulation for preparing an optical layer containing a metal oxide. The formulation can exhibit at least one of the properties of an advanced material or a high-performance material. The formulation can be used in nanotechnology processes to fabricate semiconductor device / display applications, such as semiconductor chips, or liquid crystal, quantum dot, and OLED displays fabricated on semiconductor-controlled substrates.

Description

Technical Field

[0001] This invention relates to a formulation for preparing an optical layer containing a metal oxide, a method for preparing the formulation, the use of the formulation, a method for preparing a composite material, composite materials, optical devices, and display devices. Background Technology

[0002] Cutting-edge optical devices typically include optical gratings made of composite materials, which have a supporting substrate and a complex, interlaced pattern on it, consisting of different layers or stacks of layers. Generating such complex, interlaced patterns usually requires structuring, which becomes increasingly difficult as the size of the structure to be fabricated decreases.

[0003] Besides their wide range of potential applications in various fields such as spectrometers or optical storage systems (CDs, DVDs, etc.), diffraction gratings are also a core component of so-called XR devices, primarily glasses. In this context, R stands for the term reality, and X represents different attributes such as virtual, augmented, and mixed. Therefore, diffraction gratings form the core of the so-called optical engine in XR devices, specifically augmented reality and mixed reality glasses. Virtual reality glasses, when built as head-mounted displays, are typically composed of conventional liquid crystal (LC) organic light-emitting diode (OLED) displays embedded directly in front of the user's eyes, and therefore do not necessarily require diffraction gratings. In contrast, augmented reality and mixed reality glasses are designed to provide users with an immersive visual experience, ideally as if they were not wearing any glasses. However, they can also provide and display digital information and project it into an individual's field of vision. Additional digital information is collected by identifying and analyzing the environment that an individual is observing or looking at. To deliver and project auxiliary digital information into an individual's eyes, augmented reality or mixed reality glasses are equipped with an information supply unit connected to an optical waveguide system. This system transmits optically encoded auxiliary information directly to the lenses of the glasses. Here, the information is coupled into the lenses via a diffraction grating, which splits the incident light according to its angular information and spectral band. After optical coupling, the lenses act as waveguides, allowing the light to travel to the individual's pupil. The location of the optical coupling is independent of any preferred position and is therefore unaffected by technical requirements. The direction of light propagation within the lenses is determined by the diffraction or splitting of the diffraction grating. At specific locations on the lenses, second and third diffraction gratings are used to alter the direction of light propagation, thereby forcing the light to be projected into the user's pupil. The propagation of light within the glasses is achieved through total internal reflection (TIR), thus reflecting several times between the lens interfaces until reaching another diffraction grating, which alters the internal TIR direction of the light (see...). Figure 2The second and third gratings are geometrically aligned relative to the first and coupling gratings in different directions, for example, through a specific angular distortion geometric alignment along the longitudinal axis, thereby allowing for a change in the propagation direction of the total internal reflection light. Needless to say, the lens itself or the material used to make the lens should not absorb light. Otherwise, the auxiliary information will not reach the user's pupil, or will only reach a very low light intensity. This process works regardless of whether a reflective or transmissive grating is used. Typically, lenses are equipped with both types of gratings to properly guide the light. It should also be noted that there are differences in the optical properties of reflective and transmissive gratings, but this is no longer important in the context of this invention. The basic structures of the gratings are very similar, which is more crucial at present.

[0004] However, different designs and structures exist for realizing waveguides, such as surface relief (SR) or volumetric phase holographic (VPH) gratings. These two types look very similar. In the simplest case, the grating is mounted in a certain way on the surface of the waveguide material, in this case, a lens. The grating itself consists of a series of fine structures, mostly trenches made of first-class materials with a refractive index RI 01 (material 01), but not limited to this. The geometry of the trenches can vary widely, from rectangular to V-shaped, U-shaped, and so on. The width of the trenches, including structures of different widths, their geometry, their spacing, and their depth, including different depths, are all specifically designed to affect the diffraction pattern of the incident light to be diffracted.

[0005] In the case of a VPH grating, the grooves or structures of a first-class material (material 01) with refractive index (RI 01) are filled with a second-class material (material 02) with refractive index (RI 02), wherein the difference between RI 02 and RI 01 is increasing (see [reference]). Figure 1 and Figure 3 For completeness, it should be noted that material 01 or material 02 can be composed of a stack of structured layers, each layer containing different material compositions with different refractive indices, stacked on top of each other, thereby forming material 01 or material 02 with effective or graded refractive indices RI 01 or RI 02, respectively. Furthermore, the (effective or graded) refractive indices RI 01 and RI 02 depend on the refractive index of the waveguide or lens in which the eyeglasses are made. If a high refractive index (n03 > 1.46) glass lens is used, the (effective or graded) refractive indices of material 01 and material 02 are considered to be higher than the refractive index of the lens itself, where RI values ​​of 2.0 and above can be achieved. Surface relief (SR) gratings can look similar and may also contain a second type of material as a filler for the trenches, but the trenches may also be simply air. High-performance gratings, especially VPH type gratings, can be fabricated using standard photolithography and deposition techniques known in microfabrication, such as integrated circuit manufacturing.

[0006] Standard techniques of this kind typically include physical vapor deposition (PVD) or chemical vapor deposition (CVD) processes, which often result in incomplete gap filling due to unfavorable deposition and / or layer growth properties, including increased deposition and / or growth rates at corners and edges. This incomplete gap filling creates voids within the structure to be filled by the PVD and CVD material. In addition to the formation of voids, the surface of the substrate is also covered by a PVD and / or CVD layer that is almost as thick as the maximum depth of the deepest structure filled by the deposited gap-filling material (see [link to documentation]). Figure 4 and Figure 5 However, in some applications, it may be necessary to expose the substrate surface for further processing. Therefore, it is necessary to remove unwanted excess capping layers from PVD or CVD, for example, by chemical mechanical polishing (CMP), without damaging the underlying pristine substrate surface. Although CMP is widely used in integrated circuit manufacturing processes, it is a time-consuming and expensive process, and can be considered a potential economic obstacle to the large-scale production of cutting-edge optical devices, particularly diffraction gratings. Therefore, there is a need for an advanced and cost-effective grating manufacturing solution where gaps can be filled without CMP (see...). Figure 6 ).

[0007] Therefore, more cost-effective production technologies are needed that allow for lower ownership costs. Summary of the Invention

[0008] The inventors have recently discovered that one or more major problems still require improvement, listed below: A printable formulation is provided for preparing an optical layer / composite material containing a material that provides a sufficiently high refractive index upon curing; a formulation for preparing an optical layer is provided, the formulation being capable of preparing an optical layer with improved density and / or fewer or no cracks; a formulation is provided, the formulation being capable of filling nanoscale cavities, grooves or gaps upon curing. Provided is a formulation for preparing an optical layer containing a precursor material with a high refractive index, said precursor material being sufficiently dispersed in the formulation; a simpler and / or more cost-effective method for preparing an optical layer / composite material, wherein the formulation is used; achieving a more stable formulation in which the decomposition of the cosolvent is zero or reduced, and the viscosity change in the formulation is zero or reduced; providing a formulation suitable for inkjet printing and / or enabling continuous inkjet printing.

[0009] The inventors aimed to solve one or more of the problems mentioned above.

[0010] Then, the inventors were surprised to find that one or more of the above-mentioned technical problems could be solved by the features defined in the claims.

[0011] That is, a novel formulation has been discovered for preparing optical layers containing metal oxides, preferably for preparing composite materials, more preferably for preparing layered composite materials, wherein the formulation comprises at least, substantially comprises, or comprises the following substances: - Metal alkoxides, preferably containing elements from Group 4 and / or Group 5 of the periodic table; and - An acid, wherein the acid is selected from one or more of sulfonic acids, amine hydrochlorides, and carboxylic acids.

[0012] In another aspect, the present invention also relates to a method for preparing the formulation of the present invention, said method comprising at least the following steps, substantially consisting of the following steps, or consisting of the following steps: (X) A metal alkoxide and an acid are mixed, preferably the metal alkoxide containing an element from Group 4 and / or Group 5 of the periodic table; and The acid is selected from one or more of sulfonic acids, amine hydrochlorides, and carboxylic acids.

[0013] Optionally, in step (X), a solvent is also mixed, the solvent being selected from: water, preferably acidic water having a hydrogen ion index (pH) of less than 7 and 1 or greater, preferably 1 ≤ pH < 7; an organic solvent; or a mixture of the water and one or more organic solvents.

[0014] In another aspect, the present invention also relates to the use of the formulations of the present invention for preparing optical layers containing metal oxides, preferably for preparing composite materials, and more preferably for preparing layered composite materials.

[0015] In another aspect, the invention also relates to a method for preparing a composite material containing a metal oxide, preferably the metal oxide being selected from metal dioxides, metal monooxides, or combinations thereof; the method comprising at least steps (a) and (b), substantially consisting of steps (a) and (b), or consisting of steps (a) and (b): (a) Providing the formulation of the present invention onto the surface of a substrate, preferably by a wet deposition process, more preferably by spin coating or area-selective printing, preferably by inkjet printing, and even more preferably by inkjet printing; and (b) Applying heat treatment to the formulation provided on the surface of the substrate, thereby converting at least a portion of the metal alkoxide of the formulation into a metal oxide.

[0016] Preferably, the composite material is a layered composite material, and more preferably, the layered composite material is an optical layer.

[0017] In another aspect, the present invention also relates to a composite material derived from the formulation of the present invention, preferably a layered composite material, and more preferably an optical layer.

[0018] In another aspect, the present invention also relates to a composite material obtained by the method of the present invention, preferably a layered composite material, and more preferably an optical layer.

[0019] In another aspect, the invention also relates to an optical device comprising at least: the composite material of the invention, and a substrate comprising a patterned surface or an uneven surface. Preferably, the gaps or grooves of the patterned surface or uneven surface of the substrate are at least partially filled by the composite material.

[0020] Preferably, the substrate is a patterned substrate with morphological features on its surface. Preferably, the composite material fills at least a portion of the gaps between the morphological features, and more preferably, the composite material fills the grooves of the patterned substrate.

[0021] In another aspect, the present invention also relates to a display device comprising: at least one functional medium configured to guide and modulate light or configured to emit light; and the composite material of the present invention.

[0022] Beneficial effects

[0023] This invention provides one or more of the following effects: A printable formulation is provided for preparing an optical layer / composite material containing a material that provides a sufficiently high refractive index upon curing; a formulation for preparing an optical layer is provided, the formulation being capable of preparing an optical layer with improved density and / or fewer or no cracks; a formulation is provided, the formulation being capable of filling nanoscale cavities, grooves or gaps upon curing. Provided is a formulation for preparing an optical layer containing a precursor material with a high refractive index, said precursor material being sufficiently dispersed in the formulation; a simpler and / or more cost-effective method for preparing an optical layer / composite material, wherein the formulation is used; achieving a more stable formulation in which the decomposition of the cosolvent is zero or reduced, and the viscosity change in the formulation is zero or reduced; providing a formulation suitable for inkjet printing and / or enabling continuous inkjet printing.

[0024] Preferred embodiments of the invention are described below and in the dependent claims. Attached Figure Description

[0025] Figure 1: A schematic cross-sectional view of a VPH grating with material 01 and material 02, wherein the difference between the refractive index IR 01 of material 01 and the refractive index IR 02 of material 02 is increasing.

[0026] Figure 2 : A schematic cross-sectional view of a VPH grating, which enables light diffraction (transmission case), including the propagation of diffracted light within a waveguide (e.g., a lens) via total internal reflection.

[0027] Figure 3 : A schematic cross-sectional view of a VPH grating, wherein the VPH grating has gaps (grooves) filled with a high refractive index material (material 02), wherein the difference between the refractive index of material 02 and the refractive index of material 01 on both sides of the gap (groove) is increasing.

[0028] Figure 4 : Schematic diagram of PVD-mediated or CVD-mediated gap filling process and removal of unwanted excess coating.

[0029] Figure 5 : A schematic diagram of a PVD-mediated or CVD-mediated gap-filling process that creates and leaves voids in the gaps and deposited layers.

[0030] Figure 6 : A schematic diagram of a gap-filling process using a formulation containing the metal complex of the present invention or a formulation thereof, wherein the formulation is converted into a metal oxide.

[0031] List of reference numerals

[0032] 1. Materials with RI 02

[0033] 2. Materials with RI 01

[0034] 3. Substrate (e.g., glass)

[0035] 4. Diffraction of incident light, indicated by the thick arrow.

[0036] 5. Total internal reflection (TIR) ​​of light

[0037] 6. Waveguide

[0038] 7. Structured laminates with gaps (grooves)

[0039] 8. Substrate (e.g., glass or silicon)

[0040] 9. Excessive coatings on the material (e.g., high-refractive-index materials or highly etch-resistant materials).

[0041] 10. Provide gap-filling materials (e.g., high refractive index materials or highly etch-resistant materials).

[0042] 11. Gaps

[0043] 12. Formulations of high refractive index materials (e.g., metal oxide precursors) (e.g., ink).

[0044] 13. Provide a high refractive index material (e.g., metal oxide) for gap filling, having an optional recessed geometry.

[0045] 14. Excessive covering layer (optional)

[0046] 15. Energy

[0047] Terminology Definition

[0048] In the context of this invention, the term "formulation medium" or its plural form as used herein refers to one or more compounds used as solvents, suspending agents, carriers, and / or matrices for metal alkoxides and any other components contained in a formulation. Formulation media are typically inactive compounds that do not react with the metal alkoxides and other components. Formulation media can be liquid compounds, solid compounds, or mixtures thereof. Typically, formulation media are organic compounds.

[0049] As used in this article, the term "surfactant" refers to an additive that reduces the surface tension of a given formulation.

[0050] As used herein, the term "wetting and dispersing agent" refers to an additive that improves the dispersion and penetration properties of a given formulation. In this way, the tendency of molecules to adhere to each other is reduced.

[0051] As used in this article, the term "adhesion promoter" refers to an additive that improves the adhesion of a given formulation.

[0052] As used herein, the term "polymer matrix" refers to an additive that serves as a macromolecular matrix for one or more components in a given formulation.

[0053] As used herein, the term "optical device" refers to a device containing one or more optical components for forming a light beam, including but not limited to: gratings, lenses, prisms, mirrors, optical windows, filters, polarizing optical elements, ultraviolet and infrared optical elements, and optical coatings. In the context of this invention, preferred optical devices are augmented reality (AR) glasses and / or virtual reality (VR) glasses.

[0054] As used herein, the term "display device" is an optical device configured to output / present information in a visual or tactile manner. Examples include liquid crystal displays (LCDs), light-emitting diode displays (LED displays), organic light-emitting displays (OLEDs), micro LED displays, quantum dot displays (QLEDs), AR displays, VR displays, MR displays, plasma display panels (PDPs), and electroluminescent displays (ELDs). Detailed Implementation

[0055] This invention relates to a formulation for preparing an optical layer containing a metal oxide, preferably for preparing a composite material, more preferably for preparing a layered composite material, the formulation comprising at least, substantially, or consisting of the following substances: Metal alkoxides, preferably containing elements from Group 4 and / or Group 5 of the periodic table; and An acid, wherein the acid is selected from one or more of sulfonic acids, amine hydrochlorides, and carboxylic acids.

[0056] - Metal alkoxides

[0057] According to the present invention, the formulation contains a metal alkoxide. Preferably, the metal alkoxide contains an element from Group 4 and / or Group 5 of the periodic table.

[0058] As the metal alkoxide, a publicly available metal alkoxide containing elements of Group 4 and / or Group 5 of the periodic table may be used.

[0059] In a preferred embodiment of the invention, the metal oxide precursor (preferably a metal alkoxide) is represented by the following chemical formula (IV) or chemical formula (V): M b1 O4(R b1 R b2 R b3 R b4 ) -(IV) M b2 O5(R b1 R b2 R b3 R b4 R b5 ) -(V) Where M b1 It is a tetravalent metal of Group 4 elements in the periodic table, preferably Ti, Zr or Hf; M b2 It is a pentavalent metal of a group 5 element in the periodic table, preferably Nb or Ta; R b1 R b2 R b3 R b4 and Rb5 Each is independently selected from H; D; a straight-chain alkyl group having 1 to 25 carbon atoms, preferably 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms; a branched or cyclic alkyl group having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; an aryl group having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; a straight-chain alkyl-cycloalkyl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; a branched alkyl-cycloalkyl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; a straight-chain alkyl-aryl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; and a branched alkyl-aryl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms. One or more non-adjacent CH2 groups and / or one or more adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atoms, preferably one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atoms, C=O, C=S, C=Se, C=NH; and one or more H atoms may be replaced by D. Each group can be converted by one or more groups R a replace; R a The following groups are, in each instance, identically or differently, H; D; a straight-chain alkyl or alkoxy group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms; a branched or cyclic alkyl or alkoxy group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; a straight-chain alkenyl or alkynyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; an aromatic or heteroaromatic ring system having 5 to 15 aromatic ring atoms, preferably 5 to 10 aromatic ring atoms; wherein in each of the above groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and wherein two or more adjacent substituents R a Here, they can optionally form monocyclic or polycyclic aliphatic ring systems.

[0060] According to the present invention, the total amount of the metal oxide precursor in the formulation is in the range of 0.1% to 40% by weight, preferably in the range of 1% to 35% by weight, more preferably in the range of 2% to 30% by weight, and even more preferably in the range of 3% to 28% by weight, based on the total amount of the formulation.

[0061] - Acid

[0062] According to the present invention, the formulation contains an acid selected from one or more of sulfonic acids, amine hydrochlorides, and carboxylic acids. It is believed that the acid can be used as a reaction medium.

[0063] In a preferred embodiment of the invention, the sulfonic acid is represented by the following chemical formula (I).

[0064] R a1 SO3H - (I)

[0065] in

[0066] R a1 The group is selected from straight-chain alkyl groups having 1 to 25 carbon atoms, preferably 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms; branched or cyclic alkyl groups having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; aryl groups having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; straight-chain alkyl-cycloalkyl groups having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; branched alkyl-cycloalkyl groups having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; straight-chain alkyl-aryl groups having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; and branched alkyl-aryl groups having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms. One or more non-adjacent CH2 groups of the above groups may be replaced by oxygen atoms, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS or CONH and one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; Each group can be converted by one or more groups R ax replace; R ax The following groups are, in each instance, identically or differently, H; D; a straight-chain alkyl or alkoxy group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms; a branched or cyclic alkyl or alkoxy group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; a straight-chain alkenyl or alkynyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; an aromatic or heteroaromatic ring system having 5 to 15 aromatic ring atoms, preferably 5 to 10 aromatic ring atoms; wherein in each of the above groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and wherein two or more adjacent substituents R ax Here, they can optionally form monocyclic or polycyclic aliphatic ring systems with each other; The amine hydrochloride is represented by the following chemical formula (II), HCl R a2 - (II) in R a2 Selected from N2H4, ammonia, hydroxylamine, imidazole and 1,4-diazabicyclo[2.2.2]octane; and / or The carboxylic acid is represented by the following chemical formula (III), R a3 -COOH in R a3 The group is selected from straight-chain alkyl groups having 1 to 25 carbon atoms, preferably 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms; branched or cyclic alkyl groups having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; aryl groups having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; straight-chain alkyl-cycloalkyl groups having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; branched alkyl-cycloalkyl groups having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; straight-chain alkyl-aryl groups having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; and branched alkyl-aryl groups having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms. One or more non-adjacent CH2 groups of the above groups may be replaced by oxygen atoms, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS or CONH and one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; Each group can be converted by one or more groups R ax replace; R axThe following groups are, in each instance, identically or differently, H; D; a straight-chain alkyl or alkoxy group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms; a branched or cyclic alkyl or alkoxy group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; a straight-chain alkenyl or alkynyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; an aromatic or heteroaromatic ring system having 5 to 15 aromatic ring atoms, preferably 5 to 10 aromatic ring atoms; wherein in each of the above groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and wherein two or more adjacent substituents R ax Here, they can optionally form monocyclic or polycyclic aliphatic ring systems.

[0067] In some preferred embodiments, the acid is an amine hydrochloride represented by the following chemical formula (II). HCl R a2 - (II) in R a2 The amine is selected from N2H4, ammonia, hydroxylamine, imidazole, and 1,4-diazabicyclo[2.2.2]octane. Hydrazine hydrochloride is preferably used as the hydrochloride of this type of amine.

[0068] In some preferred embodiments, the acid is a sulfonic acid represented by the following chemical formula (I).

[0069] R a1 SO3H - (I)

[0070] in

[0071] R a1 The group is selected from straight-chain alkyl groups having 1 to 25 carbon atoms, preferably 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms; branched or cyclic alkyl groups having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; aryl groups having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; straight-chain alkyl-cycloalkyl groups having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; branched alkyl-cycloalkyl groups having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; straight-chain alkyl-aryl groups having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; and branched alkyl-aryl groups having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms. One or more non-adjacent CH2 groups of the above groups may be replaced by oxygen atoms, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS or CONH and one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; Each group can be converted by one or more groups R ax replace; R ax The following groups are, in each instance, identically or differently, H; D; a straight-chain alkyl or alkoxy group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms; a branched or cyclic alkyl or alkoxy group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; a straight-chain alkenyl or alkynyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; an aromatic or heteroaromatic ring system having 5 to 15 aromatic ring atoms, preferably 5 to 10 aromatic ring atoms; wherein in each of the above groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and wherein two or more adjacent substituents R ax Here, they can optionally form monocyclic or polycyclic aliphatic ring systems.

[0072] Methanesulfonic acid (MSA), p-toluenesulfonic acid (p-TSA), and benzenesulfonic acid (BSA) are preferred as such sulfonic acids. These sulfonic acids are considered particularly suitable for use in this invention, thereby achieving improved gap-filling performance, and functioning well even when used in small amounts within the ranges described below.

[0073] In a preferred embodiment of the invention, the stoichiometric molar ratio of acid to metal alkoxide is in the range of 0.1:100 to 120:100, preferably 0.5:100 to 100:100 (stoichiometric molar amount of acid: total amount of metal alkoxide), more preferably the relative molar amount of acid based on the total amount of metal alkoxide is in the range of 1:100 to 50:100, and even more preferably 2:100 to 10:100 (relative molar amount of acid: total amount of metal alkoxide).

[0074] It is believed that when the stoichiometric molar ratio of acid to metal oxide precursor is within the above range, film stability, gap filling performance and / or improved refractive index value can be improved.

[0075] That is, from the viewpoint of better film stability and / or improved refractive index of the obtained film, it is recommended that the stoichiometric molar ratio of acid to metal alkoxide be 100:100 (acid:metal alkoxide) or less. Preferably 50:100 or less, more preferably 10:100 or less.

[0076] From the viewpoint of improved gap-filling performance, it is recommended that the stoichiometric molar ratio of acid to metal alkoxide be 0.1:100 (acid:metal alkoxide) or greater. Preferably, it is 0.5:100 or greater, more preferably 1:100 or greater.

[0077] -solvent

[0078] According to the present invention, the formulation contains a solvent selected from: acidic water having a hydrogen ion index (pH) of less than 7 and greater than 1, preferably 1 ≤ pH < 7; organic solvents; or mixtures of water and one or more organic solvents. Preferably, the formulation contains water and one or more organic solvents. More preferably, the formulation contains water and one or more organic solvents selected from one or more of the following: ethylene glycol monoalkyl ethers, preferably ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether and / or ethylene glycol monobutyl ether; diethylene glycol dialkyl ethers, preferably diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether and / or diethylene glycol dibutyl ether; propylene glycol monoalkyl ethers, preferably propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether and / or propylene glycol monopropyl ether; 1,3-dimethoxy-2-propanol, ethylene glycol alkyl ether acetate, preferably methyl cellolytic acetate and / or ethyl cellolytic acetate; propylene glycol alkyl ether acetate, preferably propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, etc. The solvent is preferably ethylene glycol monopropyl ether acetate and / or propylene glycol monopropyl ether acetate; ketone, preferably methyl ethyl ketone, acetone, methyl pentyl ketone, methyl isobutyl ketone and / or cyclohexanone; alcohol, preferably ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, propylene glycol, triethylene glycol and / or glycerol; ester, preferably ethyl 3-ethoxypropionate, methyl 3-methoxypropionate and / or ethyl lactate; and cyclic ester, preferably γ-butyrolactone; preferably the solvent is ethylene glycol monoalkyl ether, diethylene glycol dialkyl ether, propylene glycol, ethylene glycol, propylene glycol monoalkyl ether, ethylene glycol alkyl ether acetate, propylene glycol alkyl ether acetate, more preferably the solvent is selected from propylene glycol alkyl ether acetate, ethylene glycol monoalkyl ether, propylene glycol and propylene glycol monoalkyl ether, 1,3-dimethoxy-2-propanol.

[0079] The printing of structures, especially inkjet printing, is believed to be a highly cost-effective production step. Therefore, this article will describe suitable solvents for printing structures or filling cavities and structures.

[0080] After the structure is printed, deposited and filled, at least a portion of the material serving as the precursor of the metal oxide needs to be converted into the corresponding metal oxide by any known method (thermal method, photochemical method, etc.) known to those skilled in the art.

[0081] - Methods for preparing formulations

[0082] In another aspect, the present invention also relates to a method for preparing the formulation of the present invention, said method comprising at least the following steps, substantially consisting of the following steps, or consisting of the following steps: (X) A metal alkoxide and an acid are mixed, preferably the metal alkoxide containing an element from Group 4 and / or Group 5 of the periodic table; and The acid is selected from one or more of sulfonic acids, amine hydrochlorides, and carboxylic acids.

[0083] Preferably, in step (X), a solvent is also mixed, the solvent being selected from: water, preferably acidic water having a hydrogen ion index (pH) of less than 7 and greater than 1, preferably 1 ≤ pH < 7; an organic solvent; or a mixture of said water and one or more organic solvents. More preferably, in step (X), an organic solvent or a mixture of organic solvents is mixed.

[0084] In a preferred embodiment of the present invention, the method includes at least the following steps, is substantially composed of the following steps, or is composed of the following steps: (X1) The metal alkoxide is dissolved in solvent 1 to form a metal alkoxide solution, preferably the solvent 1 is a dry or anhydrous solvent; (X2) Optionally, the acid is dissolved in solvent 2 to form an acid solution, preferably the solvent 2 is a dry or anhydrous solvent, wherein the acid is selected from one or more of sulfonic acid, hydrochloride and carboxylic acid; (X3) Optionally, the acid solution obtained in step (X2) is added to the metal alkoxide solution obtained in step (X1); (X4) Mix water with solvent 3 to form an aqueous solvent; and (X5) Add the aqueous solvent to the alkoxide solution obtained in step (X1) or the metal alkoxide solution obtained in step (X3); (X6) Optionally, the acid and water are dissolved in solvent 4 to form an acid solution, to form an aqueous acid solution, preferably the solvent 4 is a dry or anhydrous solvent, wherein the acid is selected from one or more of sulfonic acid, hydrochloride and carboxylic acid; (X7) Optionally, the aqueous acid solution (X6) is added to the metal alkoxide solution (X1). The solvents 1 to 4 are independently selected from one or more of the following substances: propylene glycol monoalkyl ethers, preferably propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether and / or propylene glycol monopropyl ether; glycerol 1,3-dialkyl ether; 1,3-dimethoxy-2-propanol, more preferably the solvents are selected from propylene glycol monoalkyl ethers, glycerol 1,3-dialkyl ethers, glycerol 1,3-dialkyl ethers or any mixture thereof.

[0085] The solvents 1 to 4 (solvent 1, solvent 2, solvent 3 and solvent 4) are independently selected from one or more of the following substances: propylene glycol monoalkyl ether, preferably propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether and / or propylene glycol monopropyl ether; glycerol 1,3-dialkyl ether; 1,3-dimethoxy-2-propanol, more preferably the solvents are selected from propylene glycol monoalkyl ether, glycerol 1,3-dialkyl ether, glycerol 1,3-dialkyl ether or any mixture thereof.

[0086] Preferably, the metal alkoxide is a metal alkoxide containing elements of Group 4 and / or Group 5 of the periodic table, as described in detail in the "Metal Alkoxides" section.

[0087] Preferably, the acid selected from one or more of sulfonic acids, hydrochlorides, and carboxylic acids is an acid as described in the "Acids" section above.

[0088] - Uses

[0089] In another aspect, the present invention also relates to the use of the formulations of the present invention for preparing optical layers containing metal oxides, preferably for preparing composite materials, and more preferably for preparing layered composite materials.

[0090] - Methods for preparing composite materials containing metal oxides

[0091] In another aspect, the invention also relates to a method for preparing a composite material containing a metal oxide, preferably the metal oxide being selected from metal dioxides, metal monooxides, or combinations thereof; the method comprising at least the steps (a) and (b): (a) Providing the formulation according to any one of claims 1 to 7 onto the surface of a substrate, preferably by a wet deposition process, more preferably by spin coating or inkjet printing, and even more preferably by inkjet printing; and (b) Applying heat treatment to the formulation provided on the surface of the substrate, thereby converting at least a portion of the metal alkoxide of the formulation into a metal oxide.

[0092] Preferably, the composite material is a layered composite material, and more preferably, the layered composite material is an optical layer.

[0093] - Step (a)

[0094] According to the present invention, the formulation is preferably provided to the surface of a substrate via a wet deposition process. The wet deposition process is droplet casting, coating, or printing. More preferred coating methods are spin coating, spray coating, slot coating, or slot die coating. More preferred printing methods are flexographic printing, gravure printing, inkjet printing, EHD printing, offset printing, or screen printing. Furthermore, spray coating and inkjet printing are preferred printing methods, with inkjet printing being the most preferred.

[0095] Therefore, in a preferred embodiment, the formulation is applied to the substrate surface in step (a) by spin coating or inkjet printing. From a cost-effectiveness point of view, inkjet printing is preferred.

[0096] In a preferred embodiment of the invention, the formulation provided in step (a) of the method is an ink formulation suitable for inkjet printing. Typical requirements for the 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 30 mPa·s.

[0097] Depending on the specific problem to be solved, the formulation may need to be deposited as a uniform, dense, and thin layer covering the entire surface of the substrate by coating; or the formulation may need to be deposited locally in a structured manner, thus requiring printing. Both coating and printing require the formulation to be appropriately formulated to meet the physicochemical requirements of each coating and printing method, as well as the specific requirements of the substrate surface to be coated or printed.

[0098] In a preferred embodiment of the method of the present invention, the surface of the substrate is pretreated by a surface cleaning process. Preferred surface cleaning processes are silicon wafer cleaning processes, such as those described in W. Kern, *The Evolution of SiliconWafer 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 involving cleaning solvents (e.g., isopropanol (IPA)); wet etching processes involving hydrogen peroxide solutions (e.g., piranha solutions, SC1 and SC2), choline solutions, or HF solutions; dry etching processes involving chemical vapor deposition, ultraviolet / ozone treatment, or glow discharge techniques (e.g., O2 plasma etching); and mechanical processes involving brush scrubbing, fluid jetting, or ultrasonic techniques (acoustic treatment). The surface of the substrate may also be pretreated by silanization or atomic layer deposition (ALD) processes. Pretreatment of the substrate surface is used to alter its hydrophobicity / hydrophilicity. This improves the adhesion and filling properties of the optical metal oxide layer on the substrate surface.

[0099] In a more preferred embodiment, a wet cleaning process involving a cleaning solvent (e.g., isopropanol (IPA)) is combined with one or more of the following processes: 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 deposition, ultraviolet / ozone treatment, or glow discharge technology (e.g., O2 plasma etching); and a mechanical process involving brush scrubbing, fluid jetting, or ultrasonic technology (sonic treatment).

[0100] In a preferred embodiment, a wet cleaning process involving a cleaning solvent (e.g., isopropanol (IPA)) is combined with a mechanical process involving brush scrubbing, fluid jetting, or ultrasonic technology (sonic processing), and with a wet etching process involving a hydrogen peroxide solution (e.g., piranha solution, SC1, and SC2) or an HF solution.

[0101] Therefore, in a preferred embodiment, in step (a), the formulation is applied to the surface of the substrate by spin coating or inkjet printing.

[0102] In a preferred embodiment, the formulation is at least partially converted into a composite material on the surface of the substrate, wherein the composite material contains: a metal oxide, preferably selected from metal dioxides and / or metal monooxides; and a metal salt precursor.

[0103] In a preferred embodiment, the substrate is a patterned substrate with morphological features on its surface.

[0104] - Step (b)

[0105] It is believed that the metal alkoxide in the formulation is at least partially converted into a metal oxide on the surface of the substrate by heat treatment in step (b) to form a composite material. The composite material is preferably a layered composite material. And the solvent is typically removed in step (b).

[0106] Preferred heat treatments include exposure to elevated temperatures of 50°C to 300°C, preferably 80°C to 250°C, and more preferably 100°C to 200°C.

[0107] Heat treatment is not limited to any specific heat treatment method or time. Those skilled in the art can determine a suitable heat treatment method based on the type of substrate and formulation.

[0108] In some embodiments 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-baking (soft baking) at a temperature of 40°C to 150°C, preferably 50°C to 120°C, more preferably 60°C to 100°C; and then baking (hard baking, sintering or annealing) at a temperature of 100°C to 600°C, preferably 125°C to 450°C, more preferably 150°C to 250°C.

[0109] The purpose of pre-baking (soft baking) is to remove volatile, low-boiling-point components, such as volatile, low-boiling-point formulation media or additives, from films produced by drop casting, coating, or printing. Pre-baking is preferably performed for a period of 1 to 10 minutes. After pre-baking, a layer of substrate-adhesive film of a metal oxide precursor or mixture of metal oxide precursors is obtained. The film may still contain residual formulation media or additives.

[0110] In another alternative preferred embodiment of the method for preparing an optical metal oxide layer according to the invention, pre-baking is omitted, so that the formulation is directly converted into an optical metal oxide layer on the surface of the substrate in step (c) by baking (hard baking, sintering or annealing) at a temperature of 100°C to 600°C, preferably 125°C to 450°C, more preferably 150°C to 250°C.

[0111] The purpose of baking (hard baking, sintering, or annealing) is to transform the material or mixture of metal oxide precursors on the substrate into a metal oxide layer. Furthermore, the final properties of the metal oxide layer can be adjusted through baking. Baking is preferably performed for a period of 1 to 300 minutes, more preferably 1 to 60 minutes, to achieve a refractive index (RI) >1.7, preferably >1.8, more preferably >1.9, even more preferably >1.9, and most preferably >2.0.

[0112] Pre-baking and baking can be carried out in an ambient atmosphere or an atmosphere with increased oxygen content, thereby decomposing unwanted organic components, which can lead to a reduction in the activation energy during composite material formation.

[0113] In a preferred embodiment of the method of the present invention, the substrate is a patterned substrate having morphological features on its surface, and a layered composite material, preferably an optical layer, forms a coating covering the surface of the substrate and filling the morphological features. As a result, the morphological features are filled and leveled by the composition.

[0114] Preferred topographic features include, for example, gaps, grooves, trenches, and through-holes. These features may be uniformly or non-uniformly distributed on the surface of the substrate. Preferably, they are arranged as an array or grating on the surface of the substrate. Preferably, the topographic features have different lengths, widths, diameters, and different aspect ratios. Preferably, the topographic features have an aspect ratio of 1:20 to 20:1, more preferably 1:10 to 10:1. The aspect ratio is defined as the ratio of the width of the structure to its height (or depth). From a dimensional point of view, the depth of the topographic 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.

[0115] Preferably, the morphological features are inclined at a certain angle, such as 10° to 80°, more preferably 20° to 60°, more preferably 30° to 50°, and most preferably about 40°. Such inclined morphological features are also referred to as slopes or grooved morphological features.

[0116] It may also be necessary to locally fill the topographic features with an optical metal oxide layer, either completely or to a certain level, but without covering adjacent surfaces of the substrate where there are no topographic features to be filled.

[0117] The substrate is preferably a substrate for optical devices. The preferred substrate is made of an inorganic or organic substrate, with an inorganic substrate being more preferred. The preferred inorganic substrate contains materials selected from: ceramics, glass, fused silica, sapphire, silicon, silicon nitride, quartz, and transparent polymers or resins. There are no specific limitations on the geometry of the substrate; however, a sheet or wafer shape is preferred.

[0118] In step (a) of this method, the formulation is applied to the surface of a substrate, wherein the surface may be the surface of the substrate's base material or the surface of a layer of material different from the substrate's base material, wherein such a layer has been formed prior to the application of the formulation.

[0119] In this way, sequences of different layers (stacked layers) can be formed on top of each other. Such stacked layers can also be structured, where such structures typically have nanoscale dimensions, at least in terms of diameter, width, and / or aspect ratio.

[0120] Therefore, in a preferred embodiment, in step (b), the formulation is at least partially converted into a composite material, preferably a layered composite material, on the surface of the substrate by baking at a temperature of 100°C to 600°C, preferably 125°C to 450°C, more preferably 150°C to 250°C.

[0121] - Composite materials

[0122] In another aspect, the present invention relates to a composite material obtained by or capable of being obtained by the method of the present invention, preferably a layered composite material, and more preferably an optical layer.

[0123] In a preferred embodiment of the invention, the composite material comprises at least: a metal oxide derived from the formulation; and a metal alkoxide of the formulation, said metal alkoxide being the non-converted portion of the formulation used in step (a) of the method.

[0124] Therefore, the metal in the metal oxide is preferably Ti or Zr. More preferably, the metal oxide is selected from titanium oxide, zirconium oxide, or a combination thereof.

[0125] - Optical devices

[0126] This invention relates to an optical device comprising the composite material of the invention, preferably obtained by the method of the invention as described above, or capable of being obtained by the method of the invention. Preferably, the optical device is a waveguide for a display device selected from augmented reality (AR), virtual reality (VR), and / or mixed reality (MR) devices. Preferably, the composite material fills the gaps in the morphological features, more preferably, the composite material fills the grooves in a patterned substrate.

[0127] The present invention also relates to an optical device comprising the composite material of the present invention, which is prepared as described above using a formulation according to the present invention. Preferably, the optical device is a waveguide for augmented reality (AR) and / or virtual reality (VR) devices. Preferably, the composite material fills the gaps in the morphological features, more preferably, the composite material fills the trenches in a patterned substrate.

[0128] - Display device

[0129] Finally, the present invention relates to a display device comprising: at least one functional medium configured to modulate light or configured to emit light; and the composite material or optical device of the present invention.

[0130] Examples of the display device are selected from liquid crystal displays (LCDs), light-emitting diode displays (LED displays), organic light-emitting displays (OLEDs), micro LED displays, quantum dot displays (QLEDs), augmented reality (AR) hardware, virtual reality (VR) hardware, mixed reality (MR) hardware, plasma display panels (PDPs), and electroluminescent displays (ELDs). The AR, VR, and MR hardware are also referred to as AR, VR, and MR displays. Preferably, the display device is AR hardware, VR hardware, or MR hardware.

[0131] The present invention is further illustrated by the embodiments described below, which should not be construed as limiting. Those skilled in the art will understand that various modifications, additions, and alterations can be made to the invention without departing from the spirit and scope of the invention as defined in the claims.

[0132] Example

[0133] Reference Example 1: Formulations containing Ti butoxide (Ti(Obu)4)

[0134] Ti(Obu)₄ was added to PGME (1-methoxy-2-propanol) in a double-necked Schlenk flask connected to an inert gas / vacuum line under an argon atmosphere. The solution was stirred at room temperature, and H₂O was added dropwise to the dry PGME solution at room temperature to obtain a clear solution. The mixture was stirred for another 60 minutes. Although the amount of starting material and solvent varied, the mass concentration of the metal alkoxide starting material remained constant. Formulation 0 was finally obtained.

[0135] The mixing ratios are mentioned in Table 1 below.

[0136] Table 1

[0137] (Total: 100% by weight)

[0138] Working Example 1: Formulation containing Ti butoxide (Ti(Obu)4) and MSA

[0139] Ti(Obu)₄ was added to PGME (1-methoxy-2-propanol) in a two-necked Schlenk flask connected to an inert gas / vacuum line under an argon atmosphere. The solution was stirred at room temperature. Then, H₂O and a solution of methanesulfonic acid (MSA) in dry PGME were added dropwise at room temperature to obtain a clear solution, which was stirred for another 60 minutes. Although the amount of starting material and solvent varied, the mass concentration of the metal alkoxide starting material remained constant. Formulation 0 was finally obtained. Formulation 1 was finally obtained.

[0140] The mixing ratios are shown in Table 2 below.

[0141] Work Examples 2 to 16: Preparation of Formulations

[0142] Formulations 2 to 16 were prepared in the same manner as described in Working Example 1, except that the ingredients (raw materials) described in Table 2 were used instead of the ingredients (raw materials) used in Working Example 1.

[0143] Table 2:

[0144] Total: 100% by weight per formulation

[0145] Reference Example 2A: Preparation of Sample 0 (50 nm, 150 °C)

[0146] Formulation 0 from Reference Example 1 was spin-coated onto a Si3N4 / Si substrate pretreated with O2 plasma and having 50 nm wide trenches to form a spin-coated layer. The coated layer was then baked at 150 °C for 5 minutes. Finally, sample 0 (50 nm, 150 °C) was obtained. The obtained sample was observed by TEM analysis.

[0147] Reference Example 2B: Preparation of Sample 0 (150 nm, 150 °C)

[0148] Sample 0 (150 nm, 150 °C) was obtained in the same manner as described in Reference Example 2A, except that a Si3N4 / Si substrate with 150 nm wide trenches, pretreated with O2 plasma, was used instead of a Si3N4 / Si substrate with 50 nm wide trenches. The obtained sample 0 (150 nm, 150 °C) was observed by TEM analysis.

[0149] Working Example 17: Preparation of Sample 1 (50 nm, 100 °C) and Sample 1 (150 nm, 100 °C)

[0150] Formulation 1 from Working Example 1 (WE1) was spin-coated onto the surface of a Si3N4 / Si substrate pretreated with O2 plasma and having a 50 nm wide trench. The coated layer was then baked at 100 °C for 5 minutes. Formulation 1 was also spin-coated onto the surface of a Si3N4 / Si substrate pretreated with O2 plasma and having a 150 nm wide trench, and baked at 100 °C for 5 minutes. Finally, Sample 1 (50 nm, 100 °C) and Sample 1 (150 nm, 100 °C) were obtained. The obtained samples were observed by TEM analysis.

[0151] Working Example 18: Preparation of Sample 1 (50 nm, 200 °C) and Sample 1 (150 nm, 200 °C)

[0152] Sample 1 (50 nm, 200 °C) and Sample 1 (150 nm, 200 °C) were obtained in the same manner as described in Working Example 17, except that the coated layer was baked at 200 °C for 5 minutes. The obtained samples were observed by TEM analysis.

[0153] Working Example 19: Preparation of Sample 2 (50 nm, 100 °C) and Sample 2 (150 nm, 100 °C)

[0154] Sample 2 (50 nm, 100 °C) and Sample 2 (150 nm, 100 °C) were prepared in the same manner as described in Working Example 17, except that Formulation 2 was used instead of Formulation 1. The obtained samples were observed by TEM analysis.

[0155] Working Example 20: Preparation of Sample 2 (50 nm, 200 °C) and Sample 2 (150 nm, 200 °C)

[0156] Sample 2 (50 nm, 200 °C) and Sample 2 (150 nm, 200 °C) were prepared in the same manner as described in Working Example 17, except that Formulation 2 was used instead of Formulation 1 and a baking temperature of 200 °C for 5 minutes was used instead of 100 °C for 5 minutes. The obtained samples were observed by TEM analysis.

[0157] Working Examples 21 to 23: Preparation of Samples 3 to 5 (150 nm, 100 °C)

[0158] Samples 3 to 5 (150 nm, 100 °C) were prepared in the same manner as described in Working Example 17, except that formulations 3 to 5 were used instead of formulation 1.

[0159] Working Examples 24 to 26: Preparation of Samples 3 to 5 (150 nm, 200 °C)

[0160] Samples 3 to 5 (150 nm, 200 °C) were prepared in the same manner as described in Working Example 17, except that formulation 3 to 5 were used instead of formulation 1 and baking temperature of 200 °C for 5 minutes was used instead of 100 °C for 5 minutes.

[0161] Working Examples 27 to 37: Preparation of Samples 6 to 16 (50 nm, 100 °C) and Samples 6 to 16 (100 nm, 100 °C)

[0162] Samples 6 to 16 (50 nm, 100 °C) and 6 to 16 (100 nm, 100 °C) were prepared in the same manner as described in Working Example 17, except that formulation 6 to 16 was used instead of formulation 1. The obtained samples were observed by TEM analysis.

[0163] Working Examples 38 to 48: Preparation of Samples 6 to 16 (50 nm, 200 °C) and Samples 6 to 16 (100 nm, 200 °C)

[0164] Samples 6 to 16 (50 nm, 200 °C) and 6 to 16 (100 nm, 200 °C) were prepared in the same manner as described in Working Example 17, except that formulation 6 to 16 was used instead of formulation 1 and a baking temperature of 200 °C for 5 minutes was used instead of 100 °C for 5 minutes. The obtained samples were observed by TEM analysis.

[0165] The table below shows the results of the TEM analysis.

[0166]

[0167] "Unfilled" means that the trench is not coated or is only coated very little. That is, the lower middle part of the inner wall of the trench is not coated.

[0168] "Partial filling" means that at least all or part of the lower middle side of the inner wall of the trench is coated, but there are still large or many voids in the trench in the vertical direction.

[0169] "Fully filled" means that all voids in the trench are filled to approximately 80% to 100%, and no large voids are visible in the filled trench.

[0170] "Fill" is somewhere between "partial fill" and "full fill".

Claims

1. A formulation for preparing an optical layer containing a metal oxide, preferably for preparing a composite material, more preferably for preparing a layered composite material, said formulation comprising at least: Metal alkoxides, preferably containing elements from Group 4 and / or Group 5 of the periodic table; and An acid, wherein the acid is selected from one or more of sulfonic acids, amine hydrochlorides, and carboxylic acids.

2. The formulation according to claim 1, wherein the sulfonic acid is represented by the following chemical formula (I), R a1 SO3H - (I) in R a1 The group is selected from straight-chain alkyl groups having 1 to 25 carbon atoms, preferably 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms; branched or cyclic alkyl groups having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; aryl groups having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; straight-chain alkyl-cycloalkyl groups having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; branched alkyl-cycloalkyl groups having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; straight-chain alkyl-aryl groups having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; and branched alkyl-aryl groups having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms. One or more non-adjacent CH2 groups of the above groups may be replaced by oxygen atoms, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS or CONH and one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; Each group can be converted by one or more groups R ax replace; R ax The following groups are, in each instance, identically or differently, H; D; a straight-chain alkyl or alkoxy group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms; a branched or cyclic alkyl or alkoxy group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; a straight-chain alkenyl or alkynyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; an aromatic or heteroaromatic ring system having 5 to 15 aromatic ring atoms, preferably 5 to 10 aromatic ring atoms; wherein in each of the above groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and wherein two or more adjacent substituents R ax Here, they can optionally form monocyclic or polycyclic aliphatic ring systems with each other; The amine hydrochloride is represented by the following chemical formula (II), HCl R a2 - (II) in R a2 Selected from N2H4, ammonia, hydroxylamine, imidazole and 1,4-diazabicyclo[2.2.2]octane; and / or The carboxylic acid is represented by the following chemical formula (III), R a3 -COOH in R a3 The group is selected from straight-chain alkyl groups having 1 to 25 carbon atoms, preferably 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms; branched or cyclic alkyl groups having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; aryl groups having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; straight-chain alkyl-cycloalkyl groups having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; branched alkyl-cycloalkyl groups having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; straight-chain alkyl-aryl groups having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; and branched alkyl-aryl groups having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms. One or more non-adjacent CH2 groups of the above groups may be replaced by oxygen atoms, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS or CONH and one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; Each group can be converted by one or more groups R ax replace; R ax The following groups are, in each instance, identically or differently, H; D; a straight-chain alkyl or alkoxy group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms; a branched or cyclic alkyl or alkoxy group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; a straight-chain alkenyl or alkynyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; an aromatic or heteroaromatic ring system having 5 to 15 aromatic ring atoms, preferably 5 to 10 aromatic ring atoms; wherein in each of the above groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and wherein two or more adjacent substituents R ax Here, they can optionally form monocyclic or polycyclic aliphatic ring systems.

3. The formulation according to claim 1 or 2, wherein the stoichiometric molar ratio of the acid to the metal alkoxide is in the range of 0.1:100 to 120:100, preferably 0.5:100 to 100:100, more preferably the relative molar amount of the acid based on the total amount of the metal alkoxide is in the range of 1:100 to 50:100, and even more preferably 2:100 to 10:

100.

4. The formulation according to any one of the preceding claims, wherein the metal alkoxide is represented by the following chemical formula (IV) or chemical formula (V): M b1 O4(R b1 R b2 R b3 R b4 ) -(IV) M b2 O5(R b1 R b2 R b3 R b4 R b5 ) -(V) Where M b1 It is a tetravalent metal of Group 4 elements in the periodic table, preferably Ti, Zr or Hf; M b2 It is a pentavalent metal of a group 5 element in the periodic table, preferably Nb or Ta; R b1 R b2 R b3 R b4 and R b5 Each is independently selected from H; D; a straight-chain alkyl group having 1 to 25 carbon atoms, preferably 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms; a branched or cyclic alkyl group having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; an aryl group having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; a straight-chain alkyl-cycloalkyl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; a branched alkyl-cycloalkyl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; a straight-chain alkyl-aryl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; and a branched alkyl-aryl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms. One or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atoms. Each group can be converted by one or more groups R a replace; R a The following groups are, in each instance, identically or differently, H; D; a straight-chain alkyl or alkoxy group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms; a branched or cyclic alkyl or alkoxy group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; a straight-chain alkenyl or alkynyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; an aromatic or heteroaromatic ring system having 5 to 15 aromatic ring atoms, preferably 5 to 10 aromatic ring atoms; wherein in each of the above groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and wherein two or more adjacent substituents R a Here, they can optionally form monocyclic or polycyclic aliphatic ring systems.

5. The formulation according to any one of the preceding claims, wherein the formulation contains a solvent selected from: acidic water having a hydrogen ion index (pH) of less than 7 and greater than 1, preferably 1 ≤ pH < 7, or an organic solvent, or a mixture of water and one or more organic solvents, preferably the formulation contains water and one or more organic solvents, more preferably the formulation contains water and one or more organic solvents, wherein the organic solvent is selected from one or more of the following substances: ethylene glycol monoalkyl ethers, preferably ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether and / or ethylene glycol monobutyl ether; diethylene glycol dialkyl ethers, preferably diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether and / or diethylene glycol dibutyl ether; propylene glycol monoalkyl ethers, preferably propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether and / or propylene glycol monopropyl ether; 1,3-dimethoxy-2-propanol, ethylene glycol alkyl ether acetic acid. Esters, preferably methyl cellolytic acetate and / or ethyl cellolytic acetate; propylene glycol alkyl ether acetates, preferably propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate and / or propylene glycol monopropyl ether acetate; ketones, preferably methyl ethyl ketone, acetone, methyl pentyl ketone, methyl isobutyl ketone and / or cyclohexanone; alcohols, preferably ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, propylene glycol, triethylene glycol and / or glycerol; esters, preferably... Ethyl 3-ethoxypropionate, methyl 3-methoxypropionate and / or ethyl lactate; and cyclic esters, preferably γ-butyrolactone; preferably the solvent is ethylene glycol monoalkyl ether, diethylene glycol dialkyl ether, propylene glycol, ethylene glycol, propylene glycol monoalkyl ether, ethylene glycol alkyl ether acetate, propylene glycol alkyl ether acetate, more preferably the solvent is selected from propylene glycol alkyl ether acetate, ethylene glycol monoalkyl ether, propylene glycol and propylene glycol monoalkyl ether, 1,3-dimethoxy-2-propanol.

6. The formulation according to any one of the preceding claims, wherein the acid is a sulfonic acid represented by the following chemical formula (I): R a1 SO3H - (I) in R a1 The group is selected from straight-chain alkyl groups having 1 to 25 carbon atoms, preferably 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms; branched or cyclic alkyl groups having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; aryl groups having 3 to 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; straight-chain alkyl-cycloalkyl groups having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; branched alkyl-cycloalkyl groups having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; straight-chain alkyl-aryl groups having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; and branched alkyl-aryl groups having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms. One or more non-adjacent CH2 groups of the above groups may be replaced by oxygen atoms, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS or CONH and one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; Each group can be converted by one or more groups R ax replace; R ax The following groups are, in each instance, identically or differently, H; D; a straight-chain alkyl or alkoxy group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms; a branched or cyclic alkyl or alkoxy group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; a straight-chain alkenyl or alkynyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; an aromatic or heteroaromatic ring system having 5 to 15 aromatic ring atoms, preferably 5 to 10 aromatic ring atoms; wherein in each of the above groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and wherein two or more adjacent substituents R ax Here, they can optionally form monocyclic or polycyclic aliphatic ring systems.

7. The formulation according to any one of the preceding claims, wherein the acid is an amine hydrochloride represented by the following chemical formula (II), HCl R a2 - (II) in R a2 Selected from N2H4, ammonia, hydroxylamine, imidazole and 1,4-diazabicyclo[2.2.2]octane.

8. A method for preparing a formulation according to any one of the preceding claims, the method comprising at least the following steps: (X) A metal alkoxide and an acid are mixed, preferably the metal alkoxide containing an element from Group 4 and / or Group 5 of the periodic table; and The acid is selected from one or more of sulfonic acids, hydrochlorides, and carboxylic acids. Optionally, in step (X), a solvent is also mixed, the solvent being selected from: water, preferably acidic water having a hydrogen ion index (pH) of less than 7 and 1 or greater, preferably 1 ≤ pH < 7; an organic solvent; or a mixture of the water and one or more organic solvents.

9. A method for preparing a composite material containing a metal oxide, preferably said metal oxide is selected from metal dioxides, metal monooxides, or combinations thereof; said method comprising the steps (a) and (b): (a) Providing the formulation according to any one of claims 1 to 7 onto the surface of a substrate, preferably by a wet deposition process, more preferably by spin coating or inkjet printing, and even more preferably by inkjet printing; and (b) Applying heat treatment to the formulation provided on the surface of the substrate, thereby converting at least a portion of the metal alkoxide of the formulation into a metal oxide. Preferably, the composite material is a layered composite material, and more preferably, the layered composite material is an optical layer.

10. The method according to claim 9, wherein in step (b), the preparation is at least partially converted into a composite material on the surface of the substrate by baking the preparation at a temperature of 100°C to 600°C, preferably 125°C to 450°C, more preferably 150°C to 250°C, preferably the composite material is a layered composite material.

11. The method according to claim 9 or 10, wherein the formulation is at least partially converted into a composite material on the surface of the substrate, wherein the composite material comprises: a metal oxide, preferably selected from metal dioxides and / or metal monooxides; and a metal alkoxide.

12. The method according to any one of claims 9 to 11, wherein the substrate is a patterned substrate having morphological features on its surface.

13. A composite material derived from a formulation according to any one of claims 1 to 7, preferably the composite material being a layered composite material, and more preferably the layered composite material being an optical layer.

14. An optical device comprising: a composite material according to claim 13, and a substrate comprising a patterned surface or an uneven surface, preferably wherein the gaps or grooves of the patterned surface or uneven surface of the substrate are at least partially filled by the composite material. Preferably, the substrate is a patterned substrate with morphological features on its surface, preferably the composite material fills at least a portion of the gaps between the morphological features, and more preferably the composite material fills the grooves of the patterned substrate.

15. A display device comprising: at least one functional medium configured to guide and modulate light or configured to emit light; and a composite material according to claim 13, or an optical device according to claim 14.

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