formulation

Abstract

This invention relates to formulations for preparing optical layers containing metal oxides or mixtures of metal oxides. The formulations can exhibit at least one of the properties of an advanced material or a high-performance material. The formulations can be used in nanotechnology processes to manufacture semiconductor devices / display devices, such as 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) manufactured on semiconductor-controlled substrates.

Description

Technical Field

[0001] This invention relates to formulations containing metal oxide precursors, uses of formulations, methods for preparing formulations, methods for preparing composite materials, composite materials, optical devices, and display devices. Background Technology

[0002] Cutting-edge optical devices typically include gratings made of composite materials, which have a substrate serving as a support and complex, interlaced patterns thereon, consisting of different layers or stacks of layers. Typically, creating such complex, interlaced patterns requires structuring processes, which become increasingly challenging as the size of the structures to be fabricated decreases.

[0003] Besides its diverse applications in various fields, such as in spectrometers or in optical storage systems (CDs, DVDs, etc.), diffraction gratings are a core component of so-called XR devices (often in the form of glasses). In this context, R stands for the term reality, and X represents different attributes, such as, for example, virtual, augmented, mixed, etc. Therefore, the diffraction grating forms the core component of the so-called optical engine in XR devices, particularly in augmented reality glasses and mixed reality glasses. When built as a head-mounted display, virtual reality glasses typically consist of a conventional liquid crystal (LC) organic light-emitting diode (OLED) display embedded directly in front of the user's eyes, and therefore do not necessarily require a diffraction grating. In contrast, augmented reality glasses and mixed reality glasses are designed to allow consumers to obtain their environment visually as if they were not wearing any glasses at all. However, they also enable the delivery and transmission of digital information and its projection into the individual's field of vision. By recognizing and analyzing the environment to collect additional digital information, the individual observes or views. To convey and project supporting digital information into an individual's eyes, augmented reality or mixed reality glasses are equipped with an information supply unit coupled to an optical waveguide system that transmits optically encoded supporting information directly to the lenses of the glasses. Here, the information passes through a diffraction grating that couples the incident light into the lens and segments it according to its angular information and spectral bands via diffraction. After incident coupling, the lens acts as a waveguide, allowing light to travel to and enter the individual's pupil. The location of the incident coupling is independent of any preferred location and therefore independent of the influence of technical requirements. The direction of light passage within the lens is determined by the diffraction grating that diffracts or segments the light. At certain locations within the lens, second and third diffraction gratings are used to change the direction of light passage and thus force the light to be projected into the user's pupil. Light passage through the glasses is achieved through total internal reflection (TIR), thus bouncing several times between the eyepiece interfaces until reaching another diffraction grating, which changes the internal TIR direction of the light (see...). Figure 2 The second and third gratings are geometrically arranged in different directions relative to the first and incident coupling gratings, for example, through a certain angular distortion of 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 fabricate the lens should not be absorptive. Otherwise, supporting information will never reach the user's pupil or will only reach it with a strongly depleted light intensity. This process works regardless of whether a reflective or transmissive grating is used. Typically, lenses are equipped with two types of gratings to properly guide light. It should also be mentioned that reflective and transmissive gratings have different optical properties; however, these differences are no longer important in the context of this invention. The basic structures of the gratings are very similar, which is more important at this point.

[0004] However, different designs and structures exist for waveguides, such as surface relief (SR) or volumetric phase holography (VPH) gratings. The two types are very similar in appearance. In the simplest case, the grating is mounted on the surface of the waveguide material (in this case, a lens). The grating itself consists of an array of fine structures (primarily, but not limited to, trenches of material type 01 with a refractive index RI 01). The geometry of the trenches can be diverse, ranging from rectangular, upper V-shaped, U-shaped, and so on. The width (including structures with different widths), the trench geometry, their spacing, and their depth (including different depths) are specifically designed to influence 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 material type (material 01) having a refractive index (RI 01) are filled with a second material type (material 02) having a refractive index (RI 02), wherein RI 02 is incrementally different from RI 01 (see [reference]). Figure 1 and 3 For completeness, it should be mentioned that material 01 or material 02 can be composed of a stack of structured layers, each containing different materials with different refractive indices, stacked one on top of the other to form material 01 or material 02 with effective or graded refractive indices RI 01 or RI 02, respectively. Incidentally, the (effective or graded) refractive indices RI 01 and RI 02 depend on the refractive index of the waveguide or lens used to fabricate the eyeglasses. If eyeglass lenses with high refractive indices (n03 > 1.46) are used, the (effective or graded) refractive indices of materials 01 and 02 are considered to be higher than the refractive index of the lens itself, thus achieving and exceeding an RI value of 2.0. Surface relief (SR) gratings can look similar and may also include a second type of material as the trench filler, but the trenches can also be simply air. High-performance gratings, especially those of the VPH type, can be fabricated using standard photolithography and deposition techniques known from microfabrication, such as, for example, the fabrication of integrated circuits.

[0006] Standard techniques of this kind typically include 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 characteristics, including increased deposition and / or growth rates at corners and edges. This incomplete gap filling results in voids within the structure to be filled by the PVD and CVD materials. In addition to void formation, the substrate surface 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 gap-filling material to be deposited (see [link to documentation]). Figure 4 and 5However, in some applications, it may be necessary to expose the surface of the substrate so that it can be used for further processing. Therefore, it is necessary to remove unwanted overlays from PVD or CVD, for example, through chemical mechanical planarization (CMP), without damaging the underlying pristine substrate surface. Although CMP is a well-established process in the fabrication of integrated circuits, it is a time-consuming and expensive process and can be considered a potential economic disadvantage for the mass production of cutting-edge optics, particularly diffraction gratings. Therefore, solutions for advanced and cost-effective grating fabrication where gap filling does not require CMP (see...). Figure 6 ).

[0007] For this reason, there is a need for more cost-effective production technologies that allow for lower ownership costs. Summary of the Invention

[0008] The inventors have recently discovered that one or more significant problems still exist that require improvement, as listed below:

[0009] Expanding the parameter space allows for tuning the optical parameters / properties of the obtained optical layer / composite material through a combination of at least two metal precursors; optimizing the solid content in the formulation by increasing the solubility of the metal precursors; changing / optimizing the solvent of the formulation; providing printable formulations for preparing optical layers / composite materials containing materials that provide a sufficiently high refractive index after curing (i.e., after curing at a lower temperature); providing formulations for manufacturing optical layers / composite materials that enable the preparation of dense, crack-less, or crack-free optical layers and enable the filling of cavities, grooves, or gaps after curing.

[0010] Provides formulations for preparing optical layers / composite materials containing a metal oxide precursor material of a high refractive index, the metal oxide precursor material being well dispersed in the formulation; achieving improved layer uniformity of the resulting film, preferably by using a formulation containing one or more metal oxide precursors with a high solids content; providing a simpler and / or cost-effective method for preparing optical layers / composite materials using the formulation; achieving more stable formulations; providing suitable formulations for wet printing (i.e., for spin coating or inkjet printing) to enable continuous inkjet printing.

[0011] The inventors aimed to solve one or more of the problems mentioned above.

[0012] Then, the inventors of this invention unexpectedly discovered that one or more of the above-mentioned technical problems can be solved by the features defined in the claims.

[0013] That is, a novel formulation has been discovered, preferably for forming an optical layer comprising a metal oxide, the metal oxide comprising at least a first metal oxide precursor, a second metal oxide precursor different from the first metal oxide precursor, and a solvent, wherein the first metal oxide precursor is a metal alkoxide or metal carboxylate containing a metal element selected from the group consisting of elements of Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table;

[0014] - The second metal oxide precursor is a metal halide, metal alkoxide, or metal carboxylate containing a metal element selected from the group consisting of elements from Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table.

[0015] In another aspect, the present invention also relates to the use of the formulations of the present invention for preparing composite materials, preferably for preparing layered composite materials, more preferably for preparing optical layers, or for filling one or more grooves on a patterned or non-uniform surface of a substrate.

[0016] In another aspect, the present invention further relates to a method for preparing the formulation of the present invention, comprising at least, substantially, or consisting of the following steps (A):

[0017] (A) Mix the first metal oxide precursor, the second metal oxide precursor (different from the first metal oxide precursor), and the solvent.

[0018] - The first metal oxide precursor is a metal alkoxide or metal carboxylate containing a metallic element selected from the group consisting of elements of Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table; and

[0019] - The second metal oxide precursor is a metal halide, metal alkoxide, or metal carboxylate containing a metal element selected from the group consisting of elements from Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table.

[0020] In another aspect, the present invention further relates to a method for preparing a composite material containing a metal oxide, preferably said metal oxide being selected from metal monooxides, metal dioxides, and metal pentoxides, or combinations thereof; the method comprising the steps (a) and (b):

[0021] (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 said area-selective printing being inkjet printing; and

[0022] (b) Applying a heat treatment to the surface of the substrate to convert at least a portion of the metal oxide precursor of the preparation into a metal oxide.

[0023] Preferably, the composite material is a layered composite material, and more preferably, the layered composite material is an optical layer.

[0024] In another aspect, the present invention further relates to composite materials obtained or obtainable by the method of the present invention, preferably layered composite materials, and preferably said layered composite materials are optical layers.

[0025] In another aspect, the present invention further relates to composite materials derived from formulations of the present invention, preferably layered composite materials, and preferably said layered composite materials are optical layers.

[0026] In another aspect, the invention further relates to an optical device comprising the composite material of the invention and a substrate comprising a patterned surface or a non-uniform surface. Preferably, the gaps or grooves of the patterned surface or non-uniform surface of the substrate are at least partially filled with the composite material.

[0027] Preferably, the substrate is a patterned substrate having morphological features on its surface. Preferably, the composite material fills at least a portion of the gaps between the morphological features, more preferably, the composite material fills the grooves of the patterned substrate.

[0028] In another aspect, the present invention further 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.

[0029] Technical effects of the present invention

[0030] This invention can provide one or more of the following effects;

[0031] Expanding the parameter space allows for tuning the optical parameters / properties of the obtained optical layer / composite material through a combination of at least two metal precursors; optimizing the solid content in the formulation by increasing the solubility of the metal precursors; changing / optimizing the solvent of the formulation; providing printable formulations for preparing optical layers / composite materials containing materials that provide a sufficiently high refractive index after curing (i.e., after curing at a lower temperature); providing formulations for manufacturing optical layers / composite materials that enable the preparation of dense, crack-less, or crack-free optical layers and enable the filling of cavities, grooves, or gaps after curing.

[0032] Provides formulations for preparing optical layers / composite materials containing a metal oxide precursor material of a high refractive index, the metal oxide precursor material being well dispersed in the formulation; achieving improved layer uniformity of the resulting film, preferably by using a formulation containing one or more metal oxide precursors with a high solids content; providing a simpler and / or cost-effective method for preparing optical layers / composite materials using the formulation; achieving more stable formulations; providing suitable formulations for wet printing (i.e., for spin coating or inkjet printing) to enable continuous inkjet printing.

[0033] Preferred embodiments of the invention are described below and in the dependent claims. Attached Figure Description

[0034] Figure 1 : A schematic cross-sectional view of a VPH grating with material 01 and material 02, wherein the refractive index IR01 of material 01 is incrementally different from the refractive index IR02 of material 02.

[0035] Figure 2 A schematic cross-sectional view of a VPH grating that enables light diffraction (in the case of transmission) (including the propagation of diffracted light within a waveguide (e.g., a mirror) via total internal reflection).

[0036] Figure 3 A schematic cross-sectional view of a VPH grating providing a gap (groove) to be filled with a high refractive index material (material 02), wherein the refractive index of material 02 is incrementally different from the refractive index of material 01 on the side of the gap (groove).

[0037] Figure 4 : Schematic diagram of PVD-mediated or CVD-mediated gap filling process and removal of unwanted capping layers.

[0038] Figure 5 : A schematic diagram illustrating how PVD-mediated or CVD-mediated gap-filling processes create voids in gaps and deposited layers.

[0039] 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 converted into a metal oxide.

[0040] Figure 7a SEM image of sample 1 (preparation 1, 150°C / 5min, 150nm trench width).

[0041] Figure 7b SEM image of sample 4 (preparation 1, 150°C / 5min, 100nm trench width).

[0042] List of reference numerals

[0043] 1. Materials with RI 02

[0044] 2. Materials with RI 01

[0045] 3. Substrate (e.g., glass)

[0046] 4. Diffraction of incident light, indicated by the broad arrow.

[0047] 5. Total internal reflection (TIR) ​​of light

[0048] 6. Waveguide

[0049] 7. Structured layer stacks with gaps (grooves)

[0050] 8. Substrate (e.g., glass or silicon)

[0051] 9. A coating layer on the material (e.g., a high-refractive-index material or a highly etch-resistant material).

[0052] 10. Provide gap-filling materials (e.g., high refractive index materials or highly etch-resistant materials).

[0053] 11. Hollow

[0054] 12. Formulations of high refractive index materials (e.g., metal oxide precursors) (e.g., inks).

[0055] 13. Provide high refractive index materials (e.g., metal oxides) with optional concave geometry for gap filling.

[0056] 14. Overlay (optional)

[0057] 15. Energy

[0058] Definition of terminology

[0059] In the context of this invention, as used herein, the term "formulation medium" or the plural term "formulation medium" refers to one or more compounds used as a solvent, suspending agent, carrier, and / or matrix for metal oxide precursor compounds and any other components contained in a formulation. Formulation media are typically inert compounds that do not react with the metal oxide precursor compounds and the other components. Formulation media can be liquid compounds, solid compounds, or mixtures thereof. Typically, formulation media are organic compounds.

[0060] As used herein, the term "surfactant" refers to an additive that reduces the surface tension of a given formulation.

[0061] As used herein, the term "wetting and dispersing agent" refers to an additive that enhances the spreading and filling properties of a given formulation. In this way, the tendency of molecules to adhere to each other is reduced.

[0062] As used herein, the term "adhesion promoter" refers to an additive that increases the adhesion of a given formulation.

[0063] As used herein, the term "polymer matrix" refers to an additive that serves as a macromolecular matrix for one or more components of a given formulation.

[0064] As used herein, the term "optical device" refers to a device containing one or more optical components (including, but not limited to, gratings, lenses, prisms, mirrors, optical windows, filters, polarizing optics, UV and IR optics, and optical coatings) for forming a light beam. In the context of this invention, preferred optical devices are augmented reality (AR) glasses and / or virtual reality (VR) glasses.

[0065] As used herein, the term "display device" refers to a class of optical devices 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 / VR displays, plasma display panels (PDPs), and electroluminescent displays (ELDs). Invention Details

[0067] The present invention relates to formulations preferably used for forming optical layers comprising metal oxides, comprising at least the following, substantially consisting of the following, or consisting of the following;

[0068] A first metal oxide precursor, a second metal oxide precursor different from the first metal oxide precursor, and a solvent.

[0069] - The first metal oxide precursor is a metal alkoxide or metal carboxylate containing a metal element selected from the group consisting of elements from Group 1, Group 4, Group 5, Group 6, Group 12, Group 14 and Group 15 of the periodic table.

[0070] - The second metal oxide precursor is a metal halide, metal alkoxide, or metal carboxylate containing a metal element selected from the group consisting of elements from Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table.

[0071] - First metal oxide precursor

[0072] According to the present invention, the first metal oxide precursor is a metal alkoxide or metal carboxylate containing a metal element selected from the group consisting of elements of Group 1, Group 4, Group 5, Group 6, Group 12, Group 14 and Group 15 of the periodic table.

[0073] As the first metal oxide precursor, a known metal oxide precursor material can be used, which is a metal alkoxide or metal carboxylate containing a metal element selected from the group consisting of elements of Group 1, Group 4, Group 5, Group 6, Group 12, Group 14 and Group 15 of the periodic table.

[0074] In a preferred embodiment, the first metal oxide precursor is a metal alkoxide represented by any one of the following chemical formulas (I) to (VI);

[0075] M a1 O1R a1 - (I)

[0076] M a2 O2(R a1 R a2 ) - (II)

[0077] M a3 O3(R a1 R a2 R a3 ) - (III)

[0078] M a4 O4(R a1 R a2 R a3 R a4 ) - (IV)

[0079] M a5 O5(R a1 R a2 Ra3 R a4 R a5 ) - (V)

[0080] M a6 O6(R a1 R a2 R a3 R a4 R a5 R a6 ) - (VI)

[0081] in

[0082] M a1 It is a monovalent alkali metal, preferably M. a1 It is K, Na, or Li;

[0083] M a2 It is a divalent metal, preferably M. a2 Selected from Zn or Sn;

[0084] M a3 It is a trivalent metal, preferably M. a3 It’s Bi;

[0085] M a4 It is a tetravalent metal selected from Zr, Ti, or Hf;

[0086] M a5 It is a pentavalent metal selected from V, Nb, or Ta;

[0087] M a6 is Mo or W; and

[0088] R a1 R a2 R a3 R a4 R a5 and R a6 Each is independently 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.

[0089] One or more non-adjacent CH2 groups and / or one or more adjacent CH2 groups may be replaced by oxygen atoms, and one or more H atoms may be replaced by D atoms.

[0090] Each of the groups can be represented by one or more groups R. ax replace;

[0091] R ax Each occurrence is identical or different of 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 ynyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl or ynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; an aromatic ring system 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, and wherein two or more adjacent substituents R are present. a They can optionally form monocyclic aliphatic ring systems or polycyclic aliphatic ring systems with each other.

[0092] Examples of the first metal alkoxide are K alkoxides, Na alkoxides, Li alkoxides, Zn alkoxides, Sn alkoxides, Bi alkoxides, Zr alkoxides, Ti alkoxides, Hf alkoxides, V alkoxides, Nb alkoxides, Ta alkoxides, Mo alkoxides, W alkoxides, or any combination thereof. Preferably, the alkoxide is a butoxide, ethanol, isopropoxide, or methanol salt, more preferably an ethanol, methanol, or isopropoxide salt.

[0093] More preferably, the first metal alkoxide is selected from potassium ethoxide, potassium methoxide, sodium ethoxide, sodium methoxide, lithium ethoxide, lithium methoxide, zinc ethoxide, zinc methoxide, tin ethoxide, tin methoxide, bismuth ethoxide, bismuth methoxide, zirconium ethoxide, zirconium methoxide, titanium ethoxide, titanium methoxide, hafnium ethoxide, hafnium methoxide, vanadium ethoxide, vanadium methoxide, niobium ethoxide, niobium ethoxide (Nb(OEt)5), tantalum ethoxide, tantalum ethoxide, molybdenum ethoxide, molybdenum ethoxide, tungsten ethoxide, tungsten ethoxide, or any combination thereof.

[0094] - Second metal oxide precursor

[0095] According to the present invention, the second metal oxide precursor is a metal halide, a metal alkoxide, or a metal carboxylate, which contains a metal element selected from the group consisting of elements of Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table.

[0096] In a preferred embodiment, the second metal oxide precursor is a metal alkoxide represented by any one of the following chemical formulas (I') to (VI'), or a metal halide represented by any one of the following chemical formulas (VII) to (XII);

[0097] M a1’ O1R a1’ - (I')

[0098] M a2’ O2(R a1’ R a2’ ) - (II')

[0099] M a3’ O3(R a1’ R a2’ R a3’ ) - (III')

[0100] M a4’ O4(R a1’ R a2’ R a3’ R a4’ ) - (IV')

[0101] M a5’ O5(R a1’ R a2’ R a3’ R a4’ R a5’ ) - (V')

[0102] M a6’ O6(R a1’ R a2’ R a3’ R a4’ R a5 'R a6’ ) - (VI')

[0103] in

[0104] M a1’ It is a monovalent alkali metal, preferably M. a1’ It is K, Na, or Li;

[0105] M a2’ It is a divalent metal, preferably M. a2’ Selected from Zn or Sn;

[0106] M a3’ It is a trivalent metal, preferably M. a3’ It’s Bi;

[0107] M a4’ It is a tetravalent metal selected from Zr, Ti, or Hf;

[0108] M a5’ It is a pentavalent metal selected from V, Nb, or Ta;

[0109] M a6’ is Mo or W; and

[0110] R a1’ R a2’ R a3’ R a4’ R a5’ and R a6’ Each is independently 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.

[0111] One or more non-adjacent CH2 groups and / or one or more adjacent CH2 groups may be replaced by oxygen atoms, and one or more H atoms may be replaced by D atoms.

[0112] Each of the groups can be represented by one or more groups R. ax replace;

[0113] R ax Each occurrence is identical or different of 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 ynyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl or ynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; an aromatic ring system 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, and wherein two or more adjacent substituents R are present. a They can optionally form monocyclic aliphatic ring systems or polycyclic aliphatic ring systems with each other;

[0114] Mb1 X b1 - (VII)

[0115] M b2 X b2 2 - (VIII)

[0116] M b3 X b3 3 - (IX)

[0117] M b4 X b4 4 - (X)

[0118] M b5 X b5 5 - (XI)

[0119] M b6 X b6 6 - (XII)

[0120] in

[0121] M b1 It is a monovalent alkali metal, preferably M. b1 It is K, Na, or Li;

[0122] M b2 It is a divalent metal, preferably M. b2 Selected from Zn or Sn;

[0123] M b3 It is a trivalent metal, preferably M. b3 It’s Bi;

[0124] M b4 It is a tetravalent metal selected from Zr, Ti, or Hf;

[0125] M b5 It is a pentavalent metal selected from V, Nb, or Ta;

[0126] M b6 is Mo or W; and

[0127] X b1 X b2 X b3 X b4 X b5 X b6 Each is an independent halogen, preferably X b1 X b2 X b3 X b4 X b5 X b6 Each is independently selected from F, Cl, Br, I, and more preferably X. b1 Xb2 X b3 X b4 X b5 X b6 It is Cl.

[0128] Even more preferably, the second metal oxide precursor is a metal halide represented by any one of chemical formulas (VII) to (XII).

[0129] In a preferred embodiment of the invention, the weight ratio of the second metal oxide precursor to the first metal oxide precursor is in the range of 0.01 to 99. Preferably, it is in the range of 0.1 to 10, and more preferably, it is in the range of 0.5 to 5.

[0130] As the second metal oxide precursor, a known metal oxide precursor as described below can preferably be used. This metal oxide precursor is selected from metal halides, metal alkoxides, or metal carboxylates, and contains a metal element selected from the group consisting of elements from Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table.

[0131] Examples of the second metal halide are Sn halides, W halides, Ta halides, Sn halides, Zr halides, Zn halides, Bi halides, Mo halides, Ti halides, V halides, Hf halides, or any combination thereof.

[0132] More preferably, the second metal halide precursor is selected from ZnCl2, SnCl2, BiCl3, ZrCl4, TiCl4, HfCl4, TaCl5, NbCl5, VCl5, WCl6, MoCl6, or any combination thereof.

[0133] According to the present invention, based on the total mass of the formulation, the total content of all metal oxide precursors in the formulation is in the range of 0.1 wt.% to 50 wt.%, preferably 1 wt.% to 30 wt.%, more preferably 5 wt.% to 20 wt.%.

[0134] Based on the total amount of the formulation, the aforementioned total amount of the metal halide precursor is considered suitable for achieving improved gap filling or manufacturing thin layers placed directly on the patterned surface of the substrate / underlayer or on the non-uniform surface of the substrate / underlayer.

[0135] - Solvent

[0136] According to the present invention, the formulations of the present invention contain a solvent.

[0137] In a preferred embodiment of the invention, the solvent is an organic solvent. Preferably, the organic solvent is selected from one or more members of the group consisting of alcohols, glycols, ethers, ketones, esters, hydrocarbons, aromatic hydrocarbons, amides, and sulfones. More preferably, the organic solvent is selected from one or more members of the group consisting of: 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; ethylene glycol alkyl ether acetates, 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, etc. The solvent is preferably acetone, methyl isobutyl ketone, and / or cyclohexanone; alcohols, preferably ethanol, propanol, 1,3-dimethoxy-2-propanol, butanol, hexanol, cyclohexanol, ethylene glycol, propylene glycol, triethylene glycol, glycerol, pentanol, preferably 1-pentanol, 2-pentanol, 3-pentanol, 3-ethyl-3-pentanol, 2,4-dimethyl-3-pentanol; esters, preferably ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, and / or ethyl lactate; and cyclic esters, preferably γ-butyrolactone; preferably the solvent is selected from propylene glycol alkyl ether acetate, ethylene glycol monoalkyl ether, propylene glycol and propylene glycol monoalkyl ether, 1-pentanol, 2-pentanol, 3-pentanol, 3-ethyl-3-pentanol, 2,4-dimethyl-3-pentanol, 1,3-dimethoxy-2-propanol, or mixtures thereof.

[0138] Printing structures, especially inkjet printing, is believed to be a highly cost-effective production step. Spin coating is a convenient method and is preferred for forming uniform thin layers. Therefore, suitable solvents for spin-coating / inkjet printing of structures or filling cavities and structures are described herein.

[0139] After the printing, deposition and filling of the structure, at least a portion of the material serving as the metal halide precursor needs to be transformed into the corresponding metal oxide by any known means (thermally, photochemically, etc.) known to those skilled in the art.

[0140] - water

[0141] According to the invention, the formulation contains water, and the stoichiometry of water is in the range of 100 mol% to 400 mol% based on the total amount of the metal oxide precursor, preferably in the range of 150 mol% to 300 mol% based on the total amount of the metal oxide precursor, and even more preferably in the range of 180 mol% to 270 mol%.

[0142] - Additives

[0143] In some embodiments of the invention, the formulation may optionally contain one or more additives selected from surfactants, wetting and dispersing agents, adhesion promoters and polymer matrices.

[0144] Alternatively, in some embodiments, the formulations of the present invention do not contain any additives.

[0145] In a preferred embodiment of the invention, the formulation is an ink formulation suitable for inkjet printing. Typical requirements for ink formulations 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.

[0146] - Uses

[0147] In another aspect, the present invention also relates to the use of the formulations of the present invention for preparing composite materials, preferably for preparing layered composite materials, more preferably for preparing optical layers, or for filling one or more grooves on a patterned or non-uniform surface of a substrate.

[0148] - Methods for preparing formulations

[0149] In another aspect, the present invention also relates to a method for preparing the formulation of the present invention, which comprises at least the following steps, substantially consists of the following steps, or consists of the following steps;

[0150] The following steps (A):

[0151] (A) Mix the first metal oxide precursor, the second metal oxide precursor (different from the first metal oxide precursor), and the solvent.

[0152] - The first metal oxide precursor is a metal alkoxide or metal carboxylate containing a metallic element selected from the group consisting of elements of Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table; and

[0153] - The second metal oxide precursor is a metal halide, metal alkoxide, or metal carboxylate containing a metal element selected from the group consisting of elements from Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table.

[0154] - Methods for preparing composite materials containing metal oxides

[0155] In another aspect, the present invention also relates to a method for preparing a composite material containing a metal oxide, preferably said metal oxide is selected from metal monooxide, metal dioxide or metal pentoxide, or a combination thereof; the method comprises at least the steps (a) and (b):

[0156] (a) Preferably, the formulation of the present invention is provided to the surface of a substrate or the surface of a lower layer placed on the substrate by a wet deposition process, more preferably by spin coating or inkjet printing, and even more preferably by inkjet printing; and

[0157] (b) Applying heat treatment to the surface of the substrate or the surface of a lower layer placed on the substrate to convert at least a portion of the metal oxide precursor of the preparation into a metal oxide.

[0158] Preferably, the composite material is a layered composite material, and more preferably, the layered composite material is an optical layer.

[0159] - Step (a)

[0160] According to the present invention, the formulation can preferably be provided to the surface of a substrate or the surface of an underlying layer via a wet deposition process. The wet deposition process is drop casting, coating, or printing. More preferred coating methods include spin coating, spray coating, slot coating, or slot die coating. More preferred printing methods include flexographic printing, gravure printing, inkjet printing, EHD printing, offset printing, or screen printing. Furthermore, preferred printing methods are spray coating and inkjet printing, with inkjet printing being the most preferred method.

[0161] Therefore, in a preferred embodiment, the formulation is applied to the surface of the substrate or the surface of the underlying layer in step (a) by spin coating or inkjet printing. From a cost-effectiveness perspective, inkjet printing can be preferably used.

[0162] 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 ink formulations 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.

[0163] Depending on the specific problem to be solved, the formulation may need to be deposited by coating methods as a uniform, dense, and thin layer covering the entire surface of the substrate or the underlying layer, or the formulation may need to be deposited locally in a structured manner, thus requiring printing methods. Both coating and printing methods require the formulation to be formulated appropriately to meet the physicochemical requirements of the respective coating or printing method, as well as certain requirements regarding the surface of the substrate to be coated or printed.

[0164] 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, UV / ozone treatment, or glow discharge techniques (e.g., O2 plasma etching); and mechanical processes involving brushing, fluid jetting, or ultrasonic techniques (ultrasonic treatment). The surface of the substrate may also be pretreated by salting or atomic layer deposition (ALD) processes. Surface pretreatment of the substrate is used to alter its hydrophobicity / hydrophilicity. This can improve the adhesion and filling properties of optical metal oxide layers on the substrate surface.

[0165] In a more preferred embodiment, the 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 deposition, UV / ozone treatment, or glow discharge technology (e.g., O2 plasma etching); and a mechanical process involving brushing, fluid jetting, or ultrasonic technology (ultrasonic treatment).

[0166] In the most preferred embodiment, a wet cleaning process involving a cleaning solvent (e.g., isopropanol (IPA)) is combined with a mechanical process involving brushing, fluid jetting, or ultrasonic technology (ultrasonic treatment) and a wet etching process involving a hydrogen peroxide solution (e.g., piranha solution, SC1 and SC2), choline solution, or HF solution.

[0167] Therefore, in a preferred embodiment, in step (a), the formulation is applied to the surface of the substrate or the surface of the underlying layer by spin coating or inkjet printing.

[0168] In a preferred embodiment, the formulation is at least partially converted into a composite material on the surface of a substrate or an underlying layer, wherein the composite material contains a metal oxide preferably selected from metal monooxides, metal dioxides and / or metal pentoxides; and a metal oxide precursor.

[0169] In a preferred embodiment, the substrate is a patterned substrate having morphological features on its surface. The patterned structure of the substrate may be a lower layer placed on the substrate (e.g., the lower layer of a semiconductor device).

[0170] - Step (b)

[0171] It is believed that in step (b), the formulation is at least partially converted into a metal oxide on the surface of the substrate or on the surface of the underlying layer to form a composite material by exposure to heat treatment. The composite material is preferably a layered composite material. Furthermore, the solvent is typically removed in step (b).

[0172] Preferred heat treatment involves exposure to elevated temperatures of 50°C to 600°C, preferably 80°C to 500°C, more preferably 100°C to 300°C. It is believed that applying higher temperatures, such as in the range of 100°C to 600°C, preferably 125°C to 450°C, more preferably 150°C to 250°C, can achieve improved gap filling.

[0173] Preferredly, formulations containing a lower amount of the metal oxide precursor based on the total amount of the formulation in step (a) are used to achieve improved gap filling, for example, based on the total amount of the formulation in the range of 0.1 wt% to 30 wt%, more preferably based on the total amount of the formulation in the range of 1 wt% to 20 wt%, and even more preferably 5 wt% to 15 wt%; and in step (b), a higher temperature, such as in the range of 100°C to 600°C, preferably 125°C to 450°C, more preferably 150°C to 250°C, is applied to achieve improved gap filling.

[0174] The heat treatment method in step (b) is not limited to any particular heat treatment method or time. Depending on the type of preparation and substrate, those skilled in the art can determine a suitable heat treatment method.

[0175] In some embodiments of the method for preparing an optical metal oxide layer according to the present invention, a pre-baking step may be applied after step (a) and before step (b) to remove the solvent from the formulation. The formulation may also be partially converted into an optical metal oxide layer on the surface of the substrate 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; then, the baking (hard baking, sintering, or annealing) of step (b) is applied at a temperature of 100°C to 600°C, preferably 125°C to 450°C, more preferably 150°C to 255°C.

[0176] Pre-baking (soft baking) aims to remove volatile and low-boiling-point components, such as, for example, volatile and low-boiling-point formulation media or additives, from drop-cast, coated, or printed films. Pre-baking is preferably performed for a period of 1 to 60 minutes. After pre-baking, a layer of film with a metal oxide precursor or mixture of metal oxide precursors is obtained. The film may still contain residual formulation media or additives.

[0177] In an alternative preferred embodiment of the method for preparing an optical metal oxide layer according to the invention, pre-baking is omitted, such that the preparation is directly converted into an optical metal oxide layer on the surface of the substrate or on the surface of the underlying layer in step (b).

[0178] The purpose of baking (hard baking, sintering, or annealing) is to transform the metal oxide precursor or metal oxide precursor mixture layer on the substrate into a metal oxide layer. Furthermore, the final properties of the metal oxide layer can be adjusted through the baking process. Baking is preferably performed for a time ranging from 1 to 60 min, more preferably 2 to 20 min, and more preferably 3 to 10 min.

[0179] The pre-baking and baking (step (b)) can be carried out in an ambient atmosphere or an atmosphere with increased oxygen content to decompose unwanted organic components, which can result in a lower activation energy during composite formation and is believed to improve the physicochemical properties of the resulting layered composite material.

[0180] In a preferred embodiment of the method of the present invention, a substrate or underlying layer is patterned, including morphological features on its surface, and a layered composite material (preferably an optical layer) is formed to cover the surface of the substrate and fill the morphological features. Thus, the morphological features are filled and smoothed by the composition.

[0181] Preferred morphological 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 in an array or grating on the surface of the substrate. Preferably, the morphological features have different lengths, widths, diameters, and different aspect ratios. Preferably, the morphological 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 width of the structure relative to its height (or depth). From a dimensional perspective, the depth of the morphological 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.

[0182] It is also preferred that the morphological features are tilted at a certain angle, such as 10° to 80°, preferably 20° to 60°, more preferably 30° to 50°, and most preferably about 40°. Such tilted morphological features are also referred to as slanted or blazed morphological features.

[0183] It may also be necessary to locally fill the topographic features with an optical metal oxide layer, either completely or to a certain extent, but without covering the adjacent surfaces of the substrate (where no topographic features to be filled are available).

[0184] The substrate is preferably a substrate for optical devices. Preferred substrates are made of inorganic or organic base materials, preferably inorganic base materials. Preferred inorganic base materials contain materials selected from the list of ceramics, glass, fused silica, sapphire, silicon, silicon nitride, quartz, and transparent polymers or resins. The geometry of the substrate is not particularly limited; however, sheets or wafers are preferred.

[0185] In step (a) of the method, the formulation is applied to the surface of a substrate or the surface of an underlying layer, wherein the surface may be the surface of a base material of the substrate or the surface of a material layer different from the base material of the substrate, wherein such a layer has been formed prior to the application of the formulation.

[0186] In this way, sequences of different layers (layer stacks) can be formed on top of each other. Such layer stacks can also be structured, wherein such structures typically have nanoscale dimensions, at least in terms of diameter, width, and / or aspect ratio.

[0187] Therefore, in a preferred embodiment, in step (b), the preparation is at least partially converted into a composite material, preferably a layered composite material, on the surface of the substrate by baking it at a temperature of 50°C to 400°C (preferably 80°C to 350°C, more preferably 100°C to 300°C).

[0188] In a preferred embodiment of the invention, the heat treatment in step (b) is applied for a time ranging from 1 to 60 min, preferably 2 to 20 min, and more preferably 3 to 10 min.

[0189] In some embodiments, during the heat treatment process in step (b), 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 monooxides, metal dioxides and / or metal pentoxides; and a metal alkoxide.

[0190] - Composite materials

[0191] In another aspect, the present invention relates to composite materials derived from formulations of the present invention, preferably layered composite materials, and preferably said layered composite materials are optical layers.

[0192] In another aspect, the present invention relates to composite materials obtained or obtainable by the method of the present invention, preferably layered composite materials, and preferably said layered composite materials are optical layers.

[0193] In a preferred embodiment of the invention, the composite material comprises at least a metal oxide derived from the first and second metal oxide precursors of the formulation and one or more of the first and / or second metal oxide precursors as an unconverted portion of the formulation used in step (a) of the method.

[0194] Therefore, in some embodiments of the present invention, the composite material comprises, substantially comprises, or comprises: at least a first metal oxide precursor and a metal oxide derived from the first metal oxide precursor, wherein the first metal oxide precursor is selected from metal alkoxides or metal carboxylates and contains a metal element selected from the group consisting of elements of Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table, and optionally the composite material contains a second metal oxide precursor different from the first metal oxide precursor, selected from metal halides, metal alkoxides, or metal carboxylates and containing a metal element selected from the group consisting of elements of Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table.

[0195] Details of the metal halide precursors are described in the sections on the first metal oxide precursor and the second metal oxide precursor above.

[0196] - Optical devices

[0197] This invention relates to optical devices comprising the composite material of the invention and a substrate comprising a patterned surface or a non-uniform surface having gaps or grooves. Preferably, the gaps or grooves of the patterned surface or non-uniform surface of the substrate are at least partially filled with the composite material. Preferably, the substrate is a patterned substrate having morphological features on its surface. Preferably, the composite material fills at least a portion of the gaps of the morphological features, more preferably the composite material fills the grooves of the patterned substrate.

[0198] - Display devices

[0199] Finally, the present invention relates to display devices comprising at least one functional medium configured to modulate light or to emit light; and composite materials or optical devices of the present invention.

[0200] Examples of the display devices 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), AR / VR displays, plasma display panels (PDPs), and electroluminescent displays (ELDs).

[0201] 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 appended claims. Detailed Implementation

[0202] Example

[0203] - Analysis and measurement methods

[0204] Ellipsometry was used to determine the layer thickness (nm), refractive index (n) (RI), and absorptivity (k) of the metal oxide layer. Measurements were taken using an ellipsometer M2000 from JA Woolam at three different incident angles (65°, 70°, and 75°). The measurement data were analyzed using CompleteEase software from JA Woolam, assuming complete or near-complete transparency above 600 nm (below 560 nm), and B-spline fitting was applied to obtain the refractive index (n) and absorptivity (k). Optical constants were averaged from three to four measurement samples, each providing a different layer thickness after soft baking, hard baking, or a combination of soft baking and subsequent hard baking.

[0205] Typically, throughout all coating experiments requiring a flat and unstructured substrate of metal oxide (e.g., spectral and ellipsometric measurements), quartz and / or silicon wafers with a diameter of 2 inches are used.

[0206] SEM images were recorded using a Mira 3 LMU from Tescan, a Sigma 300VP from Carl Zeiss, or a Supra 35 from Carl Zeiss.

[0207] Substrate coating (typically on wafers) was performed using a spin coater (LabSpin 150i) from Suess. The spin coating process using a flat substrate was as follows: 0.5 ml of coating was deposited onto a static quartz wafer, followed by 30-second spin intervals at a given rotational speed, where the acceleration to reach the final rotational speed was set to 500 rpm / s². Different layers and coating thicknesses were achieved using different rotational 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 heat curing on a standard laboratory hot plate. Typically, however not limited to this, the coated layer was baked at 100°C to 200°C for 1 to 10 minutes. Layer baking was performed using a high-temperature hot plate from Harry Gestigkeit, which allows temperatures up to 600°C. Unless otherwise explicitly stated otherwise, the above conditions and parameters apply to all of the following experiments.

[0208] As an alternative film preparation technology, inkjet printing can be used. The formulation can be filled into a disposable ink cartridge (Dimatix Materials Cartridge with a nominal drop weight of 10 pL) and printing can be performed using a laboratory-scale inkjet printing device (Dimatix Materials Printer DMP-2850 or Pixdro LP50). The temperature of the printhead and substrate holder can be set up to 30°C. Squares of approximately 2 cm by 2 cm are printed at different resolutions to obtain different film thicknesses. After printing, the substrate is heat-dried and hard-baked.

[0209] Unless otherwise specified, all substrates were cleaned by immersion in 2-propanol followed by ultrasonic treatment for 10 minutes; then immersion in deionized water followed by ultrasonic treatment for 10 minutes, and drying on a heated plate at 100°C for 10 minutes. The substrates were then treated in an oxygen plasma furnace (450 watts, 5 minutes).

[0210] A structured substrate (typically a silicon wafer) is used as a square mold with sides ranging from 1.5 cm to 2 cm. The wafer mold is cut from a mother wafer, typically with a diameter of 12 inches. These structures are created and arranged on SiO2 / SiN deposited onto the wafer surface. xIn the constructed layer stack, the dimensions of these structures (e.g., the cross-sectional width and length of the trenches) are referenced to the architecture of Sematech mask 854. Typically, however not limited to, cross-sectional cleavages perpendicular to the trench array with widths of 40 nm to 50 nm are used as the primary target trench structures to study their filling behavior with wet-coated metal oxide precursors and / or metal oxides received during the thermal conversion of said metal oxide precursors. In addition to the above, cross-sections of arrays of trenches with widths of 100 nm and 150 nm are also used to study trench filling with metal oxides.

[0211] Unless otherwise specified, the structured wafer mold is coated by spin coating. For this purpose, the coating formulation (typically 0.15 ml to 0.5 ml per mold) is pipetted and cast onto the surface of the wafer. The formulation is allowed to spread and settle on the surface for one minute, followed by a step of distributing and spreading the formulation across the entire surface of the wafer mold at 500 rpm for 30 seconds, followed by a final spin step at 2000 rpm for another 60 seconds. The acceleration of the spin speed is set to 500 rpm / s². The soft and hard baking conditions for the structured wafer mold are selected to be similar to or the same as those already mentioned for planar substrates.

[0212] Unless otherwise stated elsewhere, all synthetic chemicals described were purchased from Sigma Aldrich and used without further purification. 98% anhydrous SnCl2 was used for the experiments described sequentially.

[0213] Working Example 1: Preparation of Formulation 1

[0214] Preparation 1: Nb(OEt)5 (4.15 wt%) and SnCl2 2H2O (5 wt%) with nominal solids content were prepared and dissolved in 90 wt% PGME. A clear, transparent, and colorless solution was obtained and filtered using a 0.2 µm syringe filter to remove any kind of particles and other suspended materials.

[0215] Working Examples 2 to 8: Preparation of Formulations 2 to 8

[0216] Preparations 2 to 8: Preparations 2 to 8 are prepared in the same manner as disclosed in Working Example 1 above, except that the materials mentioned in Table 1 are used in the described amounts instead of the materials used in Working Example 1.

[0217] Table 1:

[0218]

[0219] Material 1: First metal oxide precursor

[0220] Material 2: Precursor to the second metal oxide

[0221] Molar ratio: Material 1 : Material 2

[0222] Solvent ratio = Solvent 1 : Solvent 2

[0223] As disclosed in Table 1, formulations 2 to 8 contain two different solvents (solvent 1 and solvent 2), while formulation 1 contains only one solvent.

[0224] It is known that achieving good solubility in formulations with high-solids-content metal oxide precursors (such as Nb-containing metal oxide precursors) is challenging. The results show that improved solubility of one or more high-solids-content metal oxide precursors in formulations can be achieved by using two different solvents.

[0225] Working Example 9: Forming Layer

[0226] Sample 1 (a layer made from preparation 1, baked at 150°C / 5min) was prepared by the following method.

[0227] Formulation 1 from Working Example 1 (WE1) was spin-coated at 2000 rpm onto an O2 plasma-pretreated Si3N4 / Si substrate with 150 nm wide grooves on its surface. The coating was then baked at 150°C for 5 min. Finally, Sample 1 was obtained.

[0228] Working Example 10: Forming Layer

[0229] Sample 2 (a layer made from preparation 1, baked at 200°C / 5min) and Sample 3 (a layer made from preparation 1, baked at 250°C / 5min) were prepared in the same manner as described in Working Example 9 above, except that different baking temperature conditions were applied (200°C / 5min for Sample 2; 250°C / 5min for Sample 3).

[0230] Working Example 11: Observations on RI value measurement and gap filling characteristics

[0231] The samples 1 to 3 were measured using elliptic polarization and the following refractive index values ​​(RI values) were obtained.

[0232]

[0233] As indicated above, the obtained RI values ​​are extremely high, especially at lower baking temperatures. Obtaining such high RI values ​​without applying high (>250°C) baking temperatures is considered important for AR / VR devices or other applications. In this experiment, high RI values ​​were obtained even when baking at 200°C and 150°C.

[0234] Working Example 12: Observations on the properties of the forming layer and gap filling

[0235] Sample 4 (a layer made from formulation 1, baked at 150°C for 5 min, with a trench width of 100 nm) was obtained in the same manner as described in Working Example 9, except that it used “an O2 plasma pretreated Si3N4 / Si substrate with a trench width of 100 nm on the surface”.

[0236] Sample 5 (a layer made from formulation 1, baked at 200°C for 5 min, with a trench width of 100 nm) and Sample 6 (a layer made from formulation 1, baked at 250°C for 5 min, with a trench width of 100 nm) were obtained in the same manner.

[0237] Formulation 1 also exhibits highly positive interstitial filling characteristics for Si3N4 / Si substrates with 100 nm wide grooves on the surface after O2 plasma pretreatment, and shows good results.

[0238] Figure 7a This is a SEM image of sample 1 (preparation 1, 150°C / 5min, 150 nm trench width), and... Figure 7b This is a SEM image of sample 4 (preparation 1, 150°C / 5min, 100 nm trench width).

[0239] Working Example 13: Formation Layer and RI Value Measurement

[0240] Sample 7 (layer made from ingredient 2, baked at 150°C / 5min), Sample 8 (layer made from ingredient 2, baked at 200°C / 5min), Sample 9 (layer made from ingredient 2, baked at 250°C / 5min), Sample 10 (layer made from ingredient 3, baked at 150°C / 5min), Sample 11 (layer made from ingredient 3, baked at 200°C / 5min), Sample 12 (layer made from ingredient 3, baked at 250°C / 5min). Sample 13 (layer made from ingredient 4, baked at 150°C / 5min), Sample 14 (layer made from ingredient 4, baked at 200°C / 5min), Sample 15 (layer made from ingredient 4, baked at 250°C / 5min), Sample 16 (layer made from ingredient 5, baked at 150°C / 5min), Sample 17 (layer made from ingredient 5, baked at 200°C / 5min), Sample 18 (layer made from ingredient 5) Samples 19 (a layer made from ingredient 6, baked at 250°C / 5min), 20 (a layer made from ingredient 6, baked at 200°C / 5min), 21 (a layer made from ingredient 6, baked at 250°C / 5min), 22 (a layer made from ingredient 7, baked at 150°C / 5min), 23 (a layer made from ingredient 7, baked at 200°C / 5min), 24 (a layer made from ingredient 7, baked at 250°C / 5min), 25 (a layer made from ingredient 8, baked at 150°C / 5min), 26 (a layer made from ingredient 8, baked at 200°C / 5min), and 27 (a layer made from ingredient 8, baked at 250°C / 5min) were prepared in the same manner as described in Working Example 9 above, except that different baking temperature conditions and ingredients as mentioned in Table 2 were used.

[0241] Table 2:

[0242]

[0243] As indicated in Table 2, the obtained RI values ​​are extremely high, especially at lower baking temperatures. Obtaining such high RI values ​​without applying high (>250°C) baking temperatures is considered important for AR / VR devices or other applications. In this experiment, high RI values ​​were obtained even when baking at 200°C and 150°C.

[0244] Working Example 14: Formation Layer and Layer Uniformity Analysis

[0245] Sample 28 (a layer made from preparation 5, baked at 100°C for 5 min) was prepared by the following method.

[0246] Formulation 5 from Working Example 5 (WE5) was spin-coated onto a flat quartz wafer pretreated with O2 plasma at 2000 rpm. The coating was then baked at 150°C for 5 min. Finally, Sample 1 was obtained.

[0247] Samples 29 to 39 were then manufactured in the same manner as described with respect to sample 28, except that different baking conditions and preparations were used as described in Table 3.

[0248]

[0249] The results showed that the formulation containing two different solvents achieved improved layer uniformity and lower light absorption in the visible wavelength range.

Claims

1. A formulation preferably used to form an optical layer comprising a metal oxide, comprising at least a first metal oxide precursor, a second metal oxide precursor different from the first metal oxide precursor, and a solvent. - The first metal oxide precursor is a metal alkoxide or metal carboxylate containing a metal element selected from the group consisting of elements from Group 1, Group 4, Group 5, Group 6, Group 12, Group 14 and Group 15 of the periodic table. - The second metal oxide precursor is a metal halide, metal alkoxide, or metal carboxylate containing a metal element selected from the group consisting of elements from Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table.

2. The formulation as claimed in claim 1, wherein, The first metal oxide precursor is a metal alkoxide represented by any one of the following chemical formulas (I) to (VI); M a1 O1R a1 - (1) M a2 O2(R a1 R a2 ) - (II) M a3 O3(R a1 R a2 R a3 ) - (III) M a4 O4(R a1 R a2 R a3 R a4 ) - (IV) M a5 O5(R a1 R a2 R a3 R a4 R a5 ) - (V) M a6 O6(R a1 R a2 R a3 R a4 R a5 R a6 ) - (VI) in M a1 It is a monovalent alkali metal, preferably M. a1 It is K, Na, or Li; M a2 It is a divalent metal, preferably M. a2 Selected from Zn or Sn; M a3 It is a trivalent metal, preferably M. a3 It’s Bi; M a4 It is a tetravalent metal selected from Zr, Ti, or Hf; M a5 It is a pentavalent metal selected from V, Nb, or Ta; M a6 It is Mo or W; and R a1 R a2 R a3 R a4 R a5 and R a6 Each of the following is independently 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 and / or one or more adjacent CH2 groups may be replaced by oxygen atoms, and one or more H atoms may be replaced by D atoms. Each of the groups can be represented by one or more groups R. ax replace; R ax Each occurrence is identical or different of 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 ynyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl or ynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; an aromatic ring system 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, and wherein two or more adjacent substituents R are present. a They can optionally form monocyclic aliphatic ring systems or polycyclic aliphatic ring systems with each other.

3. The preparation as described in claim 1 or 2, wherein, The second metal oxide precursor is a metal alkoxide represented by any one of the following chemical formulas (I') to (VI'), or a metal halide represented by any one of the following chemical formulas (VII) to (XII); M a1’ O1R a1’ - (I') M a2’ O2(R a1’ R a2’ ) - (II’) M a3’ O3(R a1’ R a2’ R a3’ ) - (III’) M a4’ O4(R a1’ R a2’ R a3’ R a4’ ) - (IV’) M a5’ O5(R a1’ R a2’ R a3’ R a4’ R a5’ ) - (V’) M a6’ O6(R a1’ R a2’ R a3’ R a4’ R a5 'R a6’ ) - (VI') in M a1’ It is a monovalent alkali metal, preferably M. a1’ It is K, Na, or Li; M a2’ It is a divalent metal, preferably M. a2’ Selected from Zn or Sn; M a3’ It is a trivalent metal, preferably M. a3’ It’s Bi; M a4’ It is a tetravalent metal selected from Zr, Ti, or Hf; M a5’ It is a pentavalent metal selected from V, Nb, or Ta; M a6’ It is Mo or W; and R a1’ R a2’ R a3’ R a4’ R a5’ and R a6’ Each of the following is independently 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 and / or one or more adjacent CH2 groups may be replaced by oxygen atoms, and one or more H atoms may be replaced by D atoms. Each of the groups can be represented by one or more groups R. ax replace; R ax Each occurrence is identical or different of 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 ynyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl or ynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms; an aromatic ring system 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, and wherein two or more adjacent substituents R are present. a They can optionally form monocyclic aliphatic ring systems or polycyclic aliphatic ring systems with each other; M b1 X b1 - (VII) M b2 X b2 2 - (VIII) M b3 X b3 3 - (IX) M b4 X b4 4 - (X) M b5 X b5 5 - (XI) M b6 X b6 6 - (XII) in M b1 It is a monovalent alkali metal, preferably M. b1 It is K, Na, or Li; M b2 It is a divalent metal, preferably M. b2 Selected from Zn or Sn; M b3 It is a trivalent metal, preferably M. b3 It’s Bi; M b4 It is a tetravalent metal selected from Zr, Ti, or Hf; M b5 It is a pentavalent metal selected from V, Nb, or Ta; M b6 It is Mo or W; and X b1 X b2 X b3 X b4 X b5 X b6 Each is an independent halogen, preferably X b1 X b2 X b3 X b4 X b5 X b6 Each is independently selected from F, Cl, Br, I, and more preferably X. b1 X b2 X b3 X b4 X b5 X b6 It is Cl.

4. The preparation as described in any of the preceding claims, wherein, The weight ratio of the second metal oxide precursor to the first metal oxide precursor is in the range of 0.01 to 99, preferably in the range of 0.1 to 10, and more preferably in the range of 0.5 to 5.

5. The preparation as claimed in any one of the preceding claims, wherein, Based on the total mass of the formulation, the total content of all metal oxide precursors in the formulation is in the range of 0.1 w% to 50 w%, preferably 1 wt.% to 30 wt.%, more preferably 5 wt.% to 20 wt.%.

6. The preparation as claimed in any of the preceding claims, wherein, The solvent is an organic solvent. Preferably, the organic solvent is selected from one or more members of the group consisting of alcohols, glycols, ethers, ketones, esters, hydrocarbons, aromatic hydrocarbons, amides, and sulfones. More preferably, the organic solvent is selected from one or more members of the group consisting of: 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; ethylene glycol alkyl ether acetates, 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; ketone, preferably methyl ethyl ketone, acetone, methyl pentyl ketone, methyl isobutyl ketone and / or cyclohexanone; alcohol, preferably ethanol, propanol, 1,3-dimethoxy-2-propanol, butanol, hexanol, cyclohexanol, ethylene glycol, propylene glycol, triethylene glycol, glycerol, pentanol, preferably 1-pentanol, 2-pentanol, 3-pentanol, 3-ethyl-3-pentanol, 2,4-dimethyl-3-pentanol; ester, preferably The solvent is preferably ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, and / or ethyl lactate; and cyclic esters, preferably γ-butyrolactone; preferably the solvent is selected from propylene glycol alkyl ether acetate, ethylene glycol monoalkyl ether, propylene glycol and propylene glycol monoalkyl ether, 1-pentanol, 2-pentanol, 3-pentanol, 3-ethyl-3-pentanol, 2,4-dimethyl-3-pentanol, 1,3-dimethoxy-2-propanol, or any mixture thereof.

7. Use of the formulation according to any one of the preceding claims for preparing composite materials, preferably for preparing layered composite materials, more preferably for preparing optical layers, or for filling one or more grooves on a patterned or non-uniform surface of a substrate.

8. A method for preparing a formulation according to any one of claims 1 to 6, comprising at least the step (A): (A) Mixing a first metal oxide precursor, a second metal oxide precursor different from the first metal oxide precursor, and a solvent. - The first metal oxide precursor is a metal alkoxide or metal carboxylate containing a metallic element selected from the group consisting of elements of Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table; and - The second metal oxide precursor is a metal halide, metal alkoxide, or metal carboxylate containing a metal element selected from the group consisting of elements from Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table.

9. A method for preparing a composite material containing a metal oxide, preferably said metal oxide is selected from metal monooxide, metal dioxide, or metal pentoxide, or a combination thereof; said method comprising the steps (a) and (b): (a) Preferably, the formulation as described in any one of claims 1 to 6 is provided to the surface of a substrate by a wet deposition process, more preferably by spin coating or inkjet printing, and even more preferably by inkjet printing; and (b) Applying a heat treatment to the surface of the substrate to convert at least a portion of the metal alkoxide of the formulation into a metal oxide, wherein the composite material is preferably a layered composite material, and more preferably an optical layer.

10. The method of claim 9, wherein, In step (b), the preparation is at least partially converted into a composite material, preferably a layered composite material, on the surface of the substrate by baking it at a temperature of 50°C to 400°C (preferably 80°C to 350°C, more preferably 100°C to 300°C).

11. The method according to any one of claims 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 contains a metal oxide, preferably selected from metal monooxide, metal dioxide and / or metal pentoxide; and a metal alkoxide.

12. A composite material, preferably a layered composite material, preferably said layered composite material is an optical layer derived from the formulation as described in any one of claims 1 to 6.

13. A composite material, preferably a layered composite material, wherein the layered composite material is an optical layer made by the method of any one of claims 9 to 11.

14. The composite material of claim 12 or 13, comprising at least a first metal oxide precursor and a metal oxide derived from the first metal oxide precursor, wherein the first metal oxide precursor is selected from metal alkoxides or metal carboxylates, and contains a metal element selected from the group consisting of elements of Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table, and optionally the composite material contains a second metal oxide precursor different from the first metal oxide precursor, selected from metal halides, metal alkoxides, or metal carboxylates, and contains a metal element selected from the group consisting of elements of Group 1, Group 4, Group 5, Group 6, Group 12, Group 14, and Group 15 of the periodic table.

15. An optical device comprising a composite material and a substrate as claimed in any one of claims 12 to 14, the substrate comprising a patterned surface or a non-uniform surface having gaps or grooves, preferably, the gaps or grooves of the patterned surface or the non-uniform surface of the substrate are at least partially filled with the composite material, preferably, the substrate is a patterned substrate having morphological features on its surface, preferably, the composite material fills at least a portion of the gaps of the morphological features, more preferably, the composite material fills the grooves of the patterned substrate.

16. A display device comprising at least one functional medium configured to guide and modulate light or configured to emit light; and a composite material as claimed in any one of claims 12 to 14, or an optical device as claimed in claim 15.

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