formulation

Abstract

The present invention relates to a formulation for preparing an optical layer containing a metal oxide. The formulation may exhibit at least one of properties as an advanced material or as a high-performance material. The formulation may be used in the nanotechnology process to make semiconductor device / display device application, for example semiconductor chip, or a Liquid crystal display (LCD), Light emitting diode display (LED display), organic light emitting display (OLED), micro-LED display, quantum dot display (QLED), AR display, VR display, MR display, plasma (PDP) display, electroluminescent (ELD) display fabricated on a substrate controlled by semiconductors.

Description

[0001] Foreignfiling text P24-206

[0002] - 1-

[0003] Formulation

[0004] Field of the invention

[0005] The present invention relates to a formulation containing an acid and a

[0006] 5 metal alkoxide for preparing an optical layer, method for preparing a formulation, use of a formulation, method for preparing a composite, a composite, an optical device, and a display device.

[0007] Background Art

[0008] The addition of acids to control the hydrolysis and condensation of titanium (IV) alkoxide in an aqueous alcoholic solution is known in the art to afford sol-gel type formulations for the deposition of amorphous titanium dioxide. Spin coating and thermal curing allows the deposition of TiOxthin films. TiO2 films are characterized by high optical transmission across the near-

[0009] 15 UV-visible spectral region, high refractive index as well as mechanical strength and chemical inertness to aqueous and organic solvent media. Acid modifiers allow for the deposition of amorphous TiCh from sol-gel formulations into nano-confined spaces, which is important in the context of applications involving the surface relief gratings, SRGs.

[0010] 20

[0011] EP23205916.2 describes a formulation comprising a metal alkoxide, and an acid selected from one or more members of the group consisting of sulfonic acids, amine hydrochlorides and carboxylic acids. In EP23205916.2 the presence of sub stoichiometric concentrations of these specific acids can improve the capability of formulations comprising partially hydrolyzed titanium alkoxide for the deposition of nanometer sized gaps and trenches by amorphous, optically transparent, high refractive index TiOx.

[0012] Citation list

[0013] 30 Patent Literature

[0014] 1. EP23205916.2

[0015] Non patent literature Foreignfiling text P24-206

[0016] - 2-

[0017] None.

[0018] Summary of the invention

[0019] However, the inventors newly have found that there are still one or more of

[0020] 5 considerable problems for which improvement is desired, as listed below.

[0021] The addition of acids to control the hydrolysis and condensation of titanium (IV) alkoxide in an aqueous alcoholic solution is known in the art to afford sol-gel type formulations for the deposition of amorphous titanium dioxide. However, for high concentrations of the acid the resulting film will have a reduced refractive index due to excessive acid remaining in the film. But in some cases, a high acid loading is necessary to obtain long-term stable solutions or to improve the gap fill properties to prepare SRGs. Therefore, it is desired to provide a film with high refractive index, high stability, and

[0022] 15 improved gap fill properties; a high refractive index film from an acid stabilized sol-gel formation; a high refractive index film with high inorganic content; a high refractive index film with no negative impact from high acids concentration; a printable formulation for preparing an optical layer / composite containing a material which provide sufficiently high

[0023] 20 refractive index after curing; providing a formulation for preparing an optical layer for preparing an optical layer with improved density and / or crack-less or crack-free properties, providing a formulation which enables to fill up of nano-scaled cavities, trenches or gaps after curing; providing a formulation for preparing an optical layer containing a precursor material of a high refractive index material, which enables good dispersion in the formulation; simpler and / or more cost efficient method for preparing an optical layer / composite with using the formulation; realizing a more stable formulation, zero or reduced decomposition of co-solvent in the formulation, zero or reduced viscosity change of the formulation, providing a suitable

[0024] 30 formulation for ink jetting and / or realizing continuous inkjet printing. Foreignfiling text P24-206

[0025] - 3-

[0026] The inventors aimed to solve one or more of the above-mentioned problems.

[0027] Then, the present inventors have surprisingly found that one or more of the

[0028] 5 above-described technical problems can be solved by the features as defined in the claims.

[0029] Namely, it is found a novel formulation for preparing an optical layer containing a metal oxide, preferably for preparing a composite, more preferably for preparing a layered composite, comprising at least, essentially consisting of or consisting of;

[0030] - a metal alkoxide, preferably said metal alkoxide contains a group 4 and / or group 5 element of the periodic table; and

[0031] - an acid represented by the following chemical formula (la):

[0032] 15

[0033] X-Y-ZR1R2- (la) wherein,

[0034] X is -SO3H or -PO3H;

[0035] Y is 0, direct bond, alkylene group having 1 to 25 carbon atoms, aryl group

[0036] 20 having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;

[0037] Rax is at each occurrence, 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

[0038] 30 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 Foreignfiling text P24-206

[0039] - 4- atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl group 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

[0040] 5 ring atoms; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another;

[0041] Z is nitrogen atom;

[0042] R1is H, 0, alkyl group having 1 to 25 carbon atoms; aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non- adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and

[0043] 15 where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;

[0044] Raxis at each occurrence, 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

[0045] 20 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 group 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic

[0046] 30 ring system with one another;

[0047] R2is H, O, alkyl group having 1 to 25 carbon atoms; aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic Foreignfiling text P24-206

[0048] - 5- alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non- adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2;

[0049] 5 where each of groups may be substituted by one or more groups Rax;

[0050] Rax is at each occurrence, 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 group 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

[0051] 15 ring system having 5 to 15 aromatic ring atoms, preferably 5 to 10 aromatic ring atoms; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another.

[0052] 20

[0053] In another aspect, the present invention further relates to method for preparing a formulation of the present invention, containing at least, essentially consisting of, or consisting of, the following steps;

[0054] (X) mixing a metal alkoxide, preferably said metal alkoxide contains a group 4 and / or group 5 element of the periodic table; and an acid represented by the following chemical formula (la):

[0055] X-Y-ZR1R2- (la) wherein,

[0056] 30 X is -SO3H or -PO3H;

[0057] Y is O, direct bond, alkylene group having 1 to 25 carbon atoms, aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, Foreignfiling text P24-206

[0058] - 6- a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I,

[0059] 5 CN or NO2; where each of groups may be substituted by one or more groups Rax; Rax is at each occurrence, 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 group or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon

[0060] 15 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic

[0061] 20 ring system with one another;

[0062] Z is nitrogen atom;

[0063] R1is H, O, alkyl group having 1 to 25 carbon atoms; aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non- adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;

[0064] Rax is at each occurrence, identically or differently, H, D, a straight chain

[0065] 30 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 Foreignfiling text P24-206

[0066] - 7- 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 group or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon

[0067] 5 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another;

[0068] R2is H, 0, alkyl group having 1 to 25 carbon atoms; aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non- adjacent CH2 groups of the above-mentioned groups may be replaced by

[0069] 15 oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax.

[0070] Raxis at each occurrence, identically or differently, H, D, a straight chain alkyl or alkoxy group having 1 to 15 carbon atoms, preferably 1 to 10

[0071] 20 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 group 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent

[0072] 30 substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another. Foreignfiling text P24-206

[0073] - 8-

[0074] Optionally, a solvent selected from water, preferably acidic water having hydrogen ion index (pH) below 7 and 1 or more, preferably 1 ^pH<7, an organic solvent or a mixture of said water and one more organic solvent, is also mixed in step (X).

[0075] 5

[0076] In another aspect, the present invention also relates to use of the formulation of the present invention for preparing an optical layer containing a metal oxide, preferably for preparing a composite, more preferably for preparing a layered composite.

[0077] In another aspect, the present invention further relates to a method for preparing a composite containing a metal oxide; comprising at least, essentially consisting of or consisting of, the following steps (a) and (b):

[0078] (a) providing the formulation of the present invention onto a surface of a

[0079] 15 substrate, preferably by wet deposition process, more preferably by spincoating or an area selective printing, preferably said area selective printing is an ink-jetting, even more preferably by ink-jetting; and

[0080] (b) applying a thermal treatment to the formulation provided on the surface of the substrate to convert at least a part of the metal alkoxide of

[0081] 20 the formulation to a metal oxide.

[0082] Preferably said composite being a layered composite, more preferably said layered composite is an optical layer.

[0083] In another aspect, the present invention further relates to a composite, preferably being a layered composite, preferably said layered composite is an optical layer, derived from the formulation of the present invention.

[0084] In another aspect, the present invention further relates to a composite, preferably being a layered composite, preferably said layered composite is

[0085] 30 an optical layer, obtained by the method of the present invention. Foreignfiling text P24-206

[0086] - 9-

[0087] In another aspect, the present invention further relates to an optical device comprising at least the composite of the present invention, and a substrate comprising a patterned surface or an uneven surface. Preferably a gap or trench of said patterned surface or an uneven surface of the substrate is at

[0088] 5 least partly filled with said composite.

[0089] Preferably said substrate is a patterned substrate comprising topographical features on the surface thereof. Preferably said composite fills at least a part of a gap of said topographical features, more preferably said composite fills a trench of the patterned substrate.

[0090] In another aspect, the present invention further relates to a display device comprising at least one functional medium configured to direct and modulate a light or configured to emit light; and the composite of the present invention.

[0091] 15

[0092] Technical effects of the invention

[0093] The present invention may provide one or more of following effects; providing a film with high refractive index, high stability, and improved gap fill properties, a high refractive index film from an acid stabilized sol-gel

[0094] 20 formation, a high refractive index film with high inorganic content, a high refractive index film with no negative impact from high acids concentration, a printable formulation for preparing an optical layer / composite containing a material which provide sufficiently high refractive index after curing; providing a formulation for preparing an optical layer for preparing an optical layer with improved density and / or crack-less or crack-free properties, providing a formulation which enables to fill up of nano-scaled cavities, trenches or gaps after curing; providing a formulation for preparing an optical layer containing a precursor material of a high refractive index material, which enables good dispersion in the formulation; simpler and / or

[0095] 30 more cost efficient method for preparing an optical layer / composite with using the formulation; realizing a more stable formulation, zero or reduced decomposition of co-solvent in the formulation, zero or reduced viscosity Foreignfiling text P24-206

[0096] - 10- change of the formulation, providing a suitable formulation for ink jetting and / or realizing continuous inkjet printing.

[0097] Preferred embodiments of the present invention are described hereinafter

[0098] 5 and in the dependent claims.

[0099] Brief description of the figures

[0100] Figure 1A: Shows SEM image of film sample of formulation 1 (Ti precursor) baked at 150 °C showing trench filling behavior.

[0101] Figure 1B: Shows SEM image of film sample of formulation 1 (Ti precursor) baked at 200 °C showing trench filling behavior.

[0102] Figure 2A: Shows SEM image of film sample of formulation 5 (Nb precursor) baked at 150 °C showing trench filling behavior.

[0103] Figure 2B: Shows SEM image of film sample of formulation 6 (Nb

[0104] 15 precursor) baked at 150 °C showing trench filling behavior.

[0105] Figure 2C: Shows SEM image of film sample of formulation 7 (Nb precursor) baked at 150 °C showing trench filling behavior.

[0106] Figure 3A: Shows SEM image of film sample of 0.2 wt% methylsulfamic acid containing formulation (Nb precursor) showing trench filling behavior.

[0107] 20 Figure 3B: Shows SEM image of film sample of 1 wt% methylsulfamic acid containing formulation (Nb precursor) showing trench filling behavior.

[0108] Figure 3C: Shows SEM image of film sample of 4 wt% methylsulfamic acid containing formulation (Nb precursor) showing trench filling behavior.

[0109] Figure 4A: Shows SEM image of film sample of 0.2 wt% methylsulfamic acid containing formulation (Ti precursor) showing trench filling behavior. Figure 4B: Shows SEM image of film sample of 1 wt% methylsulfamic acid containing formulation (Ti precursor) showing trench filling behavior.

[0110] Figure 4C: Shows SEM image of film sample of 4 wt% methylsulfamic acid containing formulation (Ti precursor) showing trench filling behavior.

[0111] 30

[0112] List of reference signs

[0113] None. Foreignfiling text P24-206

[0114] - 11 -

[0115] Defin ition of the terms

[0116] The term “optical device” as used herein, relates to a device containing one or more optical components for forming a light beam including, but not

[0117] 5 limited to, gratings, lenses, prisms, mirrors, optical windows, filters, polarizing optics, UV and IR optics, waveguides and optical coatings. Preferred optical devices in the context of the present invention are waveguides for augmented reality (AR) device, for virtual reality (VR) device and / or for mixed reality (MR) device, or preferred optical devices are augmented reality (AR) glasses, virtual reality (VR) glasses and / or mixed reality (MR) glasses.

[0118] The term “display device” as used herein, is a kind of an optical device configured to output / present information in visual or tactile form. Examples

[0119] 15 are Liquid crystal display (LCD), Light emitting diode display (LED display), organic light emitting display (OLED), micro-LED display, quantum dot display (QLED), AR display, VR display, MR display, plasma (PDP) display, electroluminescent (ELD) display. Preferred optical devices in the context of the present invention is AR display, VR display or MR display.

[0120] 20

[0121] Detailed description of the invention

[0122] The present invention relates to a formulation for preparing an optical layer containing a metal oxide, preferably for preparing a composite, more preferably for preparing a layered composite, comprising at least, essentially consisting of or consisting of; a metal alkoxide, preferably said metal alkoxide contains a group 4 and / or group 5 element of the periodic table; and an acid represented by the following chemical formula (la):

[0123] 30 X-Y-ZR1R2- (la) wherein,

[0124] X is -SO3H or -PO3H; Foreignfiling text P24-206

[0125] - 12-

[0126] Y is 0, direct bond, alkylene group having 1 to 25 carbon atoms, aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be

[0127] 5 replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax; Rax is at each occurrence, 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

[0128] 15 atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl group 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; where in each of the above-mentioned groups, one or more H

[0129] 20 atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another.

[0130] Z is nitrogen atom;

[0131] R1is H, O, alkyl group having 1 to 25 carbon atoms; aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non- adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2;

[0132] 30 where each of groups may be substituted by one or more groups Rax;

[0133] Rax is at each occurrence, identically or differently, H, D, a straight chain alkyl or alkoxy group having 1 to 15 carbon atoms, preferably 1 to 10 Foreignfiling text P24-206

[0134] - 13- 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

[0135] 5 atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl group 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another;

[0136] R2is H, O, alkyl group having 1 to 25 carbon atoms; aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic

[0137] 15 alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non- adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax.

[0138] 20 Rax is at each occurrence, 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 group 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

[0139] 30 ring atoms; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent Foreignfiling text P24-206

[0140] - 14- substituents Rax here may optionally form a mono- or polycyclic, aliphatic ring system with one another.

[0141] - Metal alkoxides

[0142] 5 According to the present invention, the formulation contains a metal alkoxide. Preferably, said metal alkoxide contains a group 4 and / or group 5 element of the periodic table.

[0143] As said metal alkoxide, publicly available metal alkoxides containing a group 4 and / or group 5 element of the periodic table, can be used.

[0144] In a preferred embodiment of the present invention, said metal oxide precursor (preferably metal alkoxide) is represented by following chemical formula (V) or formula (VI): wherein Mb1is a tetravalent metal of a group 4 element of the periodic table, preferably it is Ti, Zr or Hf;

[0145] Mb2is a pentavalent metal of a group 5 element of the periodic table,

[0146] 20 preferably it is Nb or Ta;

[0147] Rb1, Rb2, Rb3, Rb4and Rb5are each 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 3-25 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 from 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; branched chain alkyl-cycloalkyl group having carbon atoms 6 to 25 carbon atoms, preferably 6 to 15 carbon

[0148] 30 atoms; a straight chain alkyl-aryl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; branched chain alkyl-aryl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; Foreignfiling text P24-206

[0149] - 15- where 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 atom, preferably one or more non-adjacent CH2 groups of the above- mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se,

[0150] 5 C=NH, and where one or more H atoms may be replaced by D, ; where each of groups may be substituted by one or more groups Ra; Rais at each occurrence, 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 group or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon

[0151] 15 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Ra here may optionally form a mono- or polycyclic, aliphatic

[0152] 20 ring system with one another.

[0153] -Acid

[0154] According to the present invention, the formulation contains an acid represented by the following chemical formula (la):

[0155] X-Y-ZR1R2- (la) wherein,

[0156] X is -SO3H or -PO3H;

[0157] Y is O, direct bond, alkylene group having 1 to 25 carbon atoms, aryl group

[0158] 30 having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be Foreignfiling text P24-206

[0159] - 16- replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;

[0160] 5 Rax is at each occurrence, 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 group 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

[0161] 15 ring atoms; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another;

[0162] Z is nitrogen atom;

[0163] 20 R1is H, O, alkyl group having 1 to 25 carbon atoms; aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non- adjacent CH2groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;

[0164] Rax is at each occurrence, 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

[0165] 30 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 Foreignfiling text P24-206

[0166] - 17- atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl group 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

[0167] 5 ring atoms; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another;

[0168] R2is H, 0, alkyl group having 1 to 25 carbon atoms; aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non- adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2;

[0169] 15 where each of groups may be substituted by one or more groups Rax.

[0170] Raxis at each occurrence, 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

[0171] 20 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 group 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another.

[0172] 30 It is believed that the acid can function as a reaction mediator. Foreignfiling text P24-206

[0173] - 18-

[0174] In a preferred embodiment of the invention, said acid is selected from one or more members of the group consisting of sulfamic acids, amino phosphonates and nitrogen containing sulfonic acids, preferably nitrogen containing sulfonic acids is amino sulfonic acid and nitro aromatic sulfonic

[0175] 5 acids.

[0176] It is believed that the acids facilitate the deposition of amorphous TiCh from sol-gel formulations with high refractive index due to these acids being thermally labile as they slowly decompose into volatile fragments during the hardbake step and do not remain in the thin film, therefore the resulting film has a high inorganic content and high refractive index is possible.

[0177] In a preferred embodiment of the invention, said sulfamic acid is represented by following chemical formula (I).

[0178] 15

[0179] Ra1Ra1NSO3H - (I) wherein

[0180] Ra1is, each independently, H, a straight-chain alkyl group having 1 to 25 carbon atoms, preferably 1 to 15 carbon atoms, more preferably 1 to 10

[0181] 20 carbon atoms; a branched or cyclic alkyl group having 3-25 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 from 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; a straight chain alkylcycloalkyl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; branched chain alkyl-cycloalkyl group having carbon atoms 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; branched chain alkyl-aryl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; where one or more non-adjacent CH2 groups of the

[0182] 30 above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H Foreignfiling text P24-206

[0183] - 19- atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;

[0184] Rax is at each occurrence, identically or differently, H, D, a straight chain alkyl or alkoxy group having 1 to 15 carbon atoms, preferably 1 to 10

[0185] 5 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 group 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent

[0186] 15 substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another.

[0187] In a preferred embodiment, said amino phosphonate is represented by following chemical formula (II).

[0188] 20

[0189] PO3H2Ra2NRa1Ra1- (II) wherein

[0190] Ra1is, each independently, H, 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 3-25 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 from 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; a straight chain alkylcycloalkyl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon

[0191] 30 atoms; branched chain alkyl-cycloalkyl group having carbon atoms 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; Foreignfiling text P24-206

[0192] - 20- branched chain alkyl-aryl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H

[0193] 5 atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;

[0194] Rax is at each occurrence, 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 group or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon

[0195] 15 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic

[0196] 20 ring system with one another;

[0197] Ra2is, each independently, selected from 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- 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 from 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; branched chain alkyl-cycloalkyl group having carbon atoms 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; a straight chain

[0198] 30 alkyl-aryl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; branched chain alkyl-aryl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; Foreignfiling text P24-206

[0199] - 21- where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2;

[0200] 5 where each of groups may be substituted by one or more groups Rax; Rax is at each occurrence, 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 group 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

[0201] 15 ring system having 5 to 15 aromatic ring atoms, preferably 5 to 10 aromatic ring atoms; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Rax here may optionally form a mono- or polycyclic, aliphatic ring system with one another.

[0202] 20

[0203] Preferably, said amino sulfonic acid is represented by following chemical formula (III).

[0204] NH2Ra2SO3H- (III) wherein

[0205] Ra2is, each independently, selected from 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- 25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10

[0206] 30 carbon atoms; an aryl group having 3 to 25 carbon atoms, preferably from 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 Foreignfiling text P24-206

[0207] - 22- carbon atoms; branched chain alkyl-cycloalkyl group having carbon atoms 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; branched chain alkyl-aryl group having 6 to 25 carbon atoms,

[0208] 5 preferably 6 to 15 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax; Rax is at each occurrence, 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

[0209] 15 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 group 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

[0210] 20 ring system having 5 to 15 aromatic ring atoms, preferably 5 to 10 aromatic ring atoms; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Rax here may optionally form a mono- or polycyclic, aliphatic ring system with one another.

[0211] In a preferred embodiment, said nitro aromatic sulfonic acid is represented by the following chemical formular (IV).

[0212] SO3HRa3NO2- (IV)

[0213] 30 wherein

[0214] Ra3is an aryl group having 3 to 25 carbon atoms, preferably from 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms, where one or more Foreignfiling text P24-206

[0215] - 23- non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;

[0216] 5 Rax is at each occurrence, 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 group 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

[0217] 15 ring atoms; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another.

[0218] 20 In some preferred embodiments, the acid is a sulfamic acid represented by following chemical formula (I).

[0219] Ra1Ra1NSO3H - (I) wherein

[0220] Ra1is, each independently, H, 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 3-25 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 from 3 to 15 carbon

[0221] 30 atoms, more preferably 3 to 10 carbon atoms; a straight chain alkylcycloalkyl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; branched chain alkyl-cycloalkyl group having carbon atoms 6 to 25 Foreignfiling text P24-206

[0222] - 24- 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; branched chain alkyl-aryl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; where one or more non-adjacent CH2 groups of the

[0223] 5 above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;

[0224] Rax is at each occurrence, 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

[0225] 15 atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl group 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; where in each of the above-mentioned groups, one or more H

[0226] 20 atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another.

[0227] In some preferred embodiments, the acid is a methyl sulfamic acid represented by following chemical formula (I1)

[0228] CH3H2NSO3 - (I1)

[0229] As such sulfamic acid and methyl sulfamic acid can be used preferably. It is

[0230] 30 believed that these sulfamic acids are particularly suitable for this invention to realize thin film and improved gap filling properties and they are soluble enough in the solvents. Foreignfiling text P24-206

[0231] - 25-

[0232] -Solvent

[0233] According to the present invention, the formulation of the present invention contains a solvent selected from acidic water having hydrogen ion index

[0234] 5 (pH) below 7 and 1 or more, preferably 1 ^pH<7, or an organic solvent or a mixture of water and one more of 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 members of the group consisting of ethylene glycol monoalkyl ethers, preferably it is ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether and / or ethylene glycol monobutyl ether; diethylene glycol dialkyl ethers, preferably it is diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether and / or diethylene glycol dibutyl ether;

[0235] 15 propylene glycol monoalkyl ethers, preferably it is propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether and / or propylene glycol monopropyl ether; 1 ,3-dimethoxy-2-propanol, ethylene glycol alkyl ether acetates, preferably it is methyl cellosolve acetate and / or ethyl cellosolve acetate; propylene glycol alkyl ether acetates, preferably it

[0236] 20 is propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate and / or propylene glycol monopropyl ether acetate; ketones, preferably it is methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone and / or cyclohexanone; alcohols, preferably it is ethanol, propanol, butanol, hexanol, cyclo hexanol, ethylene glycol, propylene glycol, triethylene glycol and / or glycerin; esters, preferably it is ethyl 3-ethoxypropionate, methyl 3-methoxypropionate and / or ethyl lactate; and cyclic esters, preferably it is gamma-butyro-lactone; preferably said solvent is ethylene glycol monoalkyl ethers, diethylene glycol dialkyl ethers, propylene glycol, ethylene glycol, propylene glycol monoalkyl ethers,

[0237] 30 ethylene glycol alkyl ether acetates, propylene glycol alkyl ether acetate, more preferably said solvent is selected from propylene glycol alkyl ether Foreignfiling text P24-206

[0238] - 26- acetates, ethylene glycol monoalkyl ethers, propylene glycol and propylene glycol monoalkyl ethers, 1 ,3-dimethoxy-2-propanol.

[0239] It is believed that the printing, especially ink jetting of structures is

[0240] 5 considered as a highly cost-efficient production step. Thus, suitable solvents of the formulation for printing the structures or filling up of cavities and structures, is described here.

[0241] After printing, deposition and fill up of structures, at least a part of the material as the metal oxide precursor need to become converted into the respective metal oxides by any known means know to the persons skilled in the art (thermally, photochemically, etc.).

[0242] -Method for preparing a formulation

[0243] 15 In another aspect, the present invention also relates to a method for preparing a formulation of the present invention, containing at least, essentially consisting of, or consisting of the following steps;

[0244] (X) mixing a metal alkoxide, preferably said metal alkoxide contains a group 4 and / or group 5 element of the periodic table; and

[0245] 20 an acid represented by the following chemical formula (la):

[0246] X-Y-ZR1R2- (la) wherein,

[0247] X is -SO3H or -PO3H;

[0248] Y is 0, direct bond, alkylene group having 1 to 25 carbon atoms, aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or

[0249] 30 CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax; Foreignfiling text P24-206

[0250] - 27-

[0251] Raxis at each occurrence, 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

[0252] 5 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 group 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another;

[0253] 15 Z is nitrogen atom;

[0254] R1is H, O, alkyl group having 1 to 25 carbon atoms; aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non- adjacent CH2 groups of the above-mentioned groups may be replaced by

[0255] 20 oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;

[0256] Raxis at each occurrence, 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 group or

[0257] 30 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 Foreignfiling text P24-206

[0258] - 28- ring atoms; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another;

[0259] 5 R2is H, 0, alkyl group having 1 to 25 carbon atoms; aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non- adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax.

[0260] Raxis at each occurrence, 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

[0261] 15 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 group or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon

[0262] 20 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another.

[0263] Preferably, a solvent selected from water, preferably acidic water having hydrogen ion index (pH) below 7 and 1 or more, preferably 1 ^pH<7, an organic solvent or a mixture of said water and one more organic solvents, is also mixed in step (X). More preferably, an organic solvent or a mixture of

[0264] 30 organic solvents is mixed in step (X). Foreignfiling text P24-206

[0265] - 29-

[0266] More details of said metal alkoxide, the acid, and the solvent is detailly described in the above section of “metal alkoxide”, “acid” and “solvent”.

[0267] In a preferred embodiment of the present invention, said method comprises

[0268] 5 at least, essentially consisting of or consisting of, the following steps:

[0269] (X1 ) dissolving a metal alkoxide in solvent 1 , preferably said solvent 1 is dry or water-free solvent to form a metal alkoxide solution;

[0270] (X2) optionally dissolving an acid in solvent 2, preferably said solvent 2 is dry or water-free solvent, wherein said acid is represented chemical formula (la), to form an acid solution;

[0271] (X3) optionally adding said acid solution obtained in step (X2) to the metal alkoxide solution obtained in step (X1 );

[0272] (X4) mixing water and solvent 3 to form an aqueous solvent; and

[0273] (X5) adding said aqueous solvent to the alkoxide solution obtained in step

[0274] 15 (X1 ) or the metal alkoxide solution obtained in step (X3);

[0275] (X6) optionally dissolving an acid and water in solvent 4, preferably said solvent 4 is dry or water-free solvent, wherein said acid is represented chemical formula (la), to form an acid solution to form an aqueous acid solution;

[0276] 20 (X7) optionally adding said aqueous acid solution (X6) to the metal alkoxide solution (X1 ), wherein said solvents 1 to 4 are independent from each other, selected from one or more members of the group consisting of propylene glycol monoalkyl ethers, preferably it is propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether and / or propylene glycol monopropyl ether; glycerol 1 ,3-dialkyl ethers, 1 ,3-dimethoxy-2-propanol more preferably said solvent is selected from propylene glycol monoalkyl ethers, glycerol 1 ,3-dialkyl ethers, glycerol 1 ,3-dialkyl ethers or a mixture of any of them;

[0277] 30 wherein said solvents 1 to 4 (solvent 1 , solvent 2, solvent 3 and solvent 4) are independent from each other, selected from one or more members of the group consisting of propylene glycol monoalkyl ethers, preferably it is Foreignfiling text P24-206

[0278] - 30- propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether and / or propylene glycol monopropyl ether; glycerol 1 , 3-dialky I ethers, 1 ,3-dimethoxy-2-propanol, more preferably said solvent is selected from propylene glycol monoalkyl ethers, glycerol 1 ,3-dialkyl ethers , glycerol 1 ,3-

[0279] 5 dialkyl ethers or a mixture of any of them.

[0280] Preferably, said metal alkoxide is a metal alkoxide containing a group 4 and / or group 5 element of the periodic table as detailly described in the section of “metal alkoxide”.

[0281] Preferably, said acid selected from one or more members represented by the chemical formula (la) is an acid as described in the section of “Acid” above.

[0282] 15 -Use

[0283] In another aspect, the present invention also relates to use of the formulation of the present invention for preparing an optical layer containing a metal oxide, preferably for preparing a composite, more preferably for preparing a layered composite.

[0284] 20

[0285] -Method for preparing a composite containing a metal oxide

[0286] In another aspect, the present invention also relates to a method for preparing a composite containing a metal oxide, preferably said metal oxide is selected from metal dioxide, metal mono oxide, or a combination of these; comprising at least the following steps (a) and (b):

[0287] (a) providing the formulation of any one of claims 1 to 6 over (preferably onto) the outermost surface of a substrate, preferably by wet deposition process, more preferably by spin-coating or ink-jetting, even more preferably by ink-jetting; and

[0288] 30 (b) applying a thermal treatment to the formulation provided on the surface of the substrate to convert at least a part of the metal alkoxide of the formulation to a metal oxide. Foreignfiling text P24-206

[0289] - 31 -

[0290] Preferably said composite being a layered composite, more preferably said layered composite is an optical layer.

[0291] -Step (a)

[0292] 5 According to the present invention, said formulation may preferably be provided onto a surface of a substrate by wet deposition process. Said wet deposition process is drop casting, coating, or printing. A more preferred coating method is spin coating, spray coating, slit coating, or slot-die coating. A more preferred printing method is flexo printing, gravure printing, inkjet printing, EHD printing, offset printing, or screen printing. Furthermore preferred printing method is spray coating and inkjet printing and the most preferred one is inkjet printing.

[0293] Thus, in a preferred embodiment, the formulation is applied onto a surface

[0294] 15 of a substrate by spin-coating or ink-jetting in step (a). From a viewpoint of cost effective, ink-jetting can preferably be used.

[0295] In a preferred embodiment of the present invention, the formulation provided in step (a) of the method is an ink formulation being suitable for inkjet printing. Typical requirements for ink formulations are surface

[0296] 20 tensions in the range from 20 mN / m to 40 mN / m and viscosities in the range from 3 mPa s to 30 mPa s.

[0297] Depending on the specific problem to be solved, the formulation needs to be deposited either as a homogeneous, dense and thin layer covering the entire surface of the substrate by a coating method or the formulation needs to be deposited locally in a structured manner, thus requiring a printing method. Both, coating and printing methods require formulations to be formulated in an adequate manner to comply with the physico-chemical needs of the respective coating and printing method as well as to comply

[0298] 30 with certain needs regarding the surface of the substrate to be coated or printed. Foreignfiling text P24-206

[0299] - 32-

[0300] In a preferred embodiment of the method of the present invention, the surface of the substrate is pre-treated by a surface cleaning process. Preferred surface cleaning processes are silicon wafer cleaning processes such as described in W. Kern, The Evolution of Silicon Wafer Cleaning

[0301] 5 Technology, J. Electrochem. Soc., Vol. 137, 6, 1990, 1887-1892 and in New Process Technologies for Microelectronics, RCA Review 1970, 31 , 2, 185-454. Such silicon wafer cleaning processes include wet cleaning process involving cleaning solvents (e.g. isopropanol (IPA)); wet etching processes involving hydrogen peroxide solutions (e.g. piranha solution, SC1 , and SC2), choline solutions, or HF solutions; dry etching processes involving chemical vapor etching, UV / ozone treatments or glow discharge techniques (e.g. 02 plasma etching); and mechanical processes involving brush scrubbing, fluid jet or ultrasonic techniques (sonification). The surface of the substrate can also be pre-treated by silanization or an atomic layer

[0302] 15 deposition (ALD) process. The pre-treatment of the surface of the substrate serves to modify the hydrophobicity / hydrophi licity of the surface. This can improve the adhesion and filling characteristics of the optical metal oxide layer on the surface of the substrate.

[0303] 20 In a more preferred embodiment, a wet cleaning process involving cleaning solvents (e.g. isopropanol (IPA)) is combined with one or more of a wet etching process involving hydrogen peroxide solutions (e.g. piranha solution, SC1 , and SC2), choline solutions, or HF solutions; dry etching process involving chemical vapor etching, UV / ozone treatments or glow discharge techniques (e.g. 02 plasma etching); and mechanical process involving brush scrubbing, fluid jet or ultrasonic techniques (sonification).

[0304] In a most preferred embodiment, a wet cleaning process involving cleaning solvents (e.g. isopropanol (IPA)) is combined with a mechanical process

[0305] 30 involving brush scrubbing, fluid jet or ultrasonic techniques (sonification) and with a wet etching process involving hydrogen peroxide solutions (e.g. piranha solution, SC1 , and SC2) or HF solutions; Foreignfiling text P24-206

[0306] - 33-

[0307] Thus, in a preferable embodiment, in step (a), the formulation is applied to a surface of a substrate by spin-coating or ink-jetting.

[0308] 5 In a preferable embodiment, the formulation is at least partly converted on the surface of the substrate to a composite, wherein said composite contains a metal oxide, preferably selected from metal dioxide and / or metal mono oxide; and a metal salt precursor.

[0309] In a preferable embodiment, the substrate is a patterned substrate comprising topographical features on the surface thereof.

[0310] -Step (b)

[0311] It is believed that metal alkoxide in the formulation is at least partly

[0312] 15 converted in step (b) on the surface of the substrate to a metal oxide to form a composite by exposure to thermal treatment. Said composite is preferably a layered composite. And said solvent is usually removed in step (b).

[0313] 20 According to the present invention, the phrase “the formulation is at least partly converted in step (b)” means that, regardless of the ratio concerning the total amount of the formulation, the composite containing the metal oxide is generated from the formulation in step (b).

[0314] Said conversion from the formulation to the composite in step (b) may be either complete or partial. In case of partial conversion from the formulation to the composite, the obtained composite may include components of the formulation such as metal alkoxide, solvent and / or the acid.

[0315] 30 Preferred thermal treatment includes exposure to elevated temperature from 50 to 300 °C, preferably it is from 80 to 250°C, more preferably from 100 to 200°C. Foreignfiling text P24-206

[0316] - 34-

[0317] Thermal treatment is not limited to any specific thermal treatment methods or times. Depending on the type of substrate and formulation, a person skilled in the art can determine suitable thermal treatment methods.

[0318] 5

[0319] In some embodiments of the method for preparing an optical metal oxide layer according to the present invention, the formulation is converted in step (c) on the surface of the substrate to an optical metal oxide layer by prebaking (soft baking) at a temperature from 40 to 150 °C, preferably from 50 to 120 °C, more preferably from 60 to 100 °C; and then baking (hard baking, sintering or annealing) at a temperature from 100 to 600 °C, preferably from 125 to 450 °C, more preferably from 150 to 250 °C.

[0320] Pre-baking (soft baking) serves the purpose to remove volatile and low

[0321] 15 boiling components such as e.g. volatile and low boiling formulation media or additives from the drop casted, coated or printed films. Pre-baking is preferably carried out for a period of 1 to 10 minutes. After pre-baking, layers of substrate adhering films of metal oxide precursor or metal oxide precursor mixtures are obtained. The films may still comprise residual

[0322] 20 formulation media or additives.

[0323] In an alternative preferred embodiment of the method for preparing an optical metal oxide layer according to the present invention, pre-baking is omitted so that the formulation is converted in step (c) on the surface of the substrate to an optical metal oxide layer directly by baking (hard baking, sintering or annealing) at a temperature from 100 to 600 °C, preferably from 125 to 450 °C, more preferably from 150 to 250 °C.

[0324] Baking (hard baking, sintering or annealing) serves the purpose to convert

[0325] 30 the material as the metal oxide precursor or metal oxide precursor mixture layers on the substrate into a metal oxide layer. Moreover, the final properties of the metal oxide layer may be adjusted by the baking Foreignfiling text P24-206

[0326] - 35- treatment. Baking is preferably carried out for a period of 1 to 300 minutes, preferably 1 to 60 minutes to achieve a refractive index (Rl) of > 1 .7, preferably > 1.8, more preferably > 1.9, even more preferably > 1.9, most preferably > 2.0.

[0327] 5

[0328] Pre-baking and baking may be carried out under ambient atmosphere or atmospheres with increased oxygen content in order to decompose unwanted organic components, which can lead to a lower activation energy when the composite is formed.

[0329] In a preferred embodiment of the method of present invention, the substrate is a patterned substrate comprising topographical features on the surface thereof, and the layered composite, preferably it is an optical layer, forms a coating layer covering the surface of the substrate and filling said

[0330] 15 topographical features. As a result, the topographical features are filled and levelled by said composition.

[0331] Preferred topographical features include, for example, gaps, grooves, trenches and vias. Topographical features may be distributed uniformly or

[0332] 20 non-uniform ly over the surface of the substrate. Preferably, they are arranged as an array or grating on the surface of the substrate. It is preferred that the topographical features have different lengths, widths, diameters as well as different aspect ratios. It is preferred that said topographical 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 structure to its height (or depth). From the viewpoint of dimension, the depth of the topographical features is preferably in the range from 10 nm to 10 pm, more preferably 50 nm to 5 pm, and most preferably 100 nm to 1 pm.

[0333] 30 It is also preferred that the topographical features are inclined at a certain angle, such as an angle from 10 to 80°, preferably from 20 to 60°, more preferably from 30 to 50°, most preferably about 40°. Such inclined Foreignfiling text P24-206

[0334] - 36- topographical features are also referred to as slanted or blazed topographical features.

[0335] It may also be necessary to fill topographical features locally with optical

[0336] 5 metal oxide layer, either completely or to a certain level, but not to cover adjacent surfaces of the substrate, where no topographical features to be filled are available.

[0337] The substrate is preferably a substrate of an optical device. Preferred substrates are made of inorganic or organic base materials, preferably inorganic base materials. Preferred inorganic base materials contain materials selected from the list consisting of ceramics, glass, fused silica, sapphire, silicon, silicon nitride, quartz, and transparent polymers or resins. The geometry of the substrate is not specifically limited, however, preferred

[0338] 15 are sheets or wafers.

[0339] In step (a) of the method, the formulation is applied onto a surface of a substrate, wherein said surface may be either a surface of a base material of the substrate or a surface of a layer of a material being different from the

[0340] 20 base material of the substrate, wherein such layer has been formed prior to applying said formulation.

[0341] In this way, sequences of different layers (layer stacks) can be formed on top of one another. Such layer stacks may also be structured, wherein such structures typically have dimensions in the nanometer scale, at least with respect to diameter, width and / or aspect ratio.

[0342] Thus, in a preferable embodiment, in step (b), the formulation is at least partly converted on the surface of the substrate to a composite, preferably it

[0343] 30 being a layered composite, by baking it at a temperature from 100 to 600 °C, preferably it is from 125 to 450°C, more preferably from 150 to 250°C. Foreignfiling text P24-206

[0344] - 37-

[0345] - Composite

[0346] In another aspect, the present invention relates to a composite, preferably being a layered composite, preferably said layered composite is an optical

[0347] 5 layer, derived from the formulation of the present invention or, obtained or obtainable by the method of the present invention.

[0348] In a preferred embodiment of the present invention, the composite comprises at least a metal oxide derived from the formulation and the metal alkoxide of the formulation as a non-converted part of the formulation used in step (a) of the method.

[0349] Thus, preferably said metal of the metal oxide is Ti or Nb. More preferably said metal oxide is selected from the group consisting of Titanium oxide, Niobium ethoxide or a combination of these.

[0350] 15

[0351] The present invention relates to an optical device comprising the composite of the present invention, which is preferably obtainable or obtained by the method of the present invention as described above.

[0352] 20 It is preferred that the optical device is 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 optics, UV and IR optics, waveguides and optical coatings. Preferred optical devices in the context of the present invention are waveguides for augmented reality (AR) device, for virtual reality (VR) device and / or for mixed reality (MR) device, or preferred optical devices are augmented reality (AR) glasses, virtual reality (VR) glasses and / or mixed reality (MR) glasses.

[0353] 30 -Display device Foreignfiling text P24-206

[0354] - 38-

[0355] Finally, the present invention relates to a display device comprising at least one functional medium configured to modulate a light or configured to emit light; and the composite, or an optical device of the present invention.

[0356] 5 Examples of said display device is selected from a Liquid crystal display (LCD), Light emitting diode display (LED display), organic light emitting display (OLED), micro-LED display, quantum dot display (QLED), Augmented Reality (AR) hardware, Virtual Reality (VR) hardware, Mixed Reality (MR) hardware, plasma (PDP) display and an electroluminescent (ELD) display. Said AR, VR and MR hardware are also called as AR, VR and MR display. Preferably said display device is AR hardware, VR hardware or MR hardware.

[0357] The present invention is further illustrated by the examples following

[0358] 15 hereinafter which shall in no way be construed as limiting. The skilled person will acknowledge that various modifications, additions and alternations may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims.

[0359] 20 Examples

[0360] Working example 1 : Ti butoxide (Ti(Obu)4) and Sulfamic acid containing formulations 1 & 2

[0361] Ti(Obu)4is added to PGME (1-methoxy-2-propanol) under argon atmosphere in two neck Schlenk flask connected to inert gas / vacuum line. The solution is stirred at room temperature. Then a solution of H2O and sulfamic acid in dry PGME is added dropwise at room temperature, affording a clear solution that is stirred for another 60 mins. While the solvent and amounts of starting materials are varied, mass concentration of metal alkoxide starting material is not changed. Finally, Formulation 1 is

[0362] 30 obtained. Formulation 2 is also prepared in the same manner as formulation 1 except that the raw material mixing ratio used are different. The mixing ratio is indicated in below table 1. Foreignfiling text P24-206

[0363] - 39-

[0364] Table 1

[0365] 5

[0366] (Total: 100wt%)

[0367] Working example 2: Forming a film from formulation 1

[0368] Formulation 1 from example 1 is spin coated onto an O2 plasma pretreated silicon substrate to form a spin coated layer. Then the coated layer is baked at 150°C for 5 minutes. Finally, sample 1 is obtained. The conditions are listed in table 2. The obtained sample is observed by TEM analysis.

[0369] 15 Working example 3: Forming films from formulations 1 & 2

[0370] Samples 2-8 are obtained in the same manner as described in working example 2 except for that an O2 plasma pretreated glass substrate is used instead of the O2 plasma pretreated silicon substrate for samples 3, 4, 7, 8, and a baking temperature at 250°C is used for samples 2, 4, 6, 8. The

[0371] 20 conditions are listed in table 2. The obtained samples are observed by TEM analysis.

[0372] Table 2

[0373] 30 Foreignfiling text P24-206

[0374] - 40-

[0375] As can be seen in table 2, all the Rl of films heated to 150 and 250°C reach

[0376] 5 a high Rl amount > 1 .84.

[0377] All the samples obtained showed excellent gap fill results, especially at 150°C hardbake temperature. Figure 1A and 1 B show TEM images of film samples made from formulation 1 baked at 150 and 200°C conditions. As can be seen in the figures, voids can be observed at higher temperature, but the material film still looks continuous and homogenous. This indicates that the decomposition products leaving the thin film do not compromise the film structure.

[0378] Working example 4: Preparation of formulations 3 to 7

[0379] Formulations 3-7 are prepared in the same manner as described in working example 1 above except for that a Nb(OEt)s precursor is used instead of Ti(OBu)4 for formulations 5-7, and water is not added to formulations 3, 4, 6, 7. The conditions applied are shown in table 3 below.

[0380] Table 3

[0381] 30 Working example 5: Forming films from formulations 3 to 7

[0382] Samples 9-23 are obtained in the same manner as described in working example 2 except for that different baking temperature conditions (200°C Foreignfiling text P24-206

[0383] - 41- for samples 10, 13, 16, 19, 22 and 250°C for samples 11 , 14, 17, 20, 23) and formulations (samples 9-11 are made from formulation 3, samples 12- 14 are made from formulation 4, samples 15-17 are made from formulation 5, samples 18-20 are made from formulation 6, samples 21-23 are made

[0384] 5 from formulation 7) are applied. The conditions are shown in table 4 below.

[0385] Table 4

[0386] Working example 6: Forming films from formulations 3 to 7

[0387] Samples 24-28 are obtained in the same manner as described in working example 2 except for that a baking time of 30 min and different formulations

[0388] 30 (sample 24 is made from formulation 3, sample 25 is made from formulation 4, sample 26 is made from formulation 5, sample 27 is made from Foreignfiling text P24-206 formulation 6, sample 28 is made from formulation 7) and used. The conditions are shown in table 5 below.

[0389] Table 5

[0390] 5

[0391] As can be seen in table 5, samples 24-28 that are baked for 30 min have higher Rl values than samples 9, 12, 15, 18, 21 that are only baked for 5 min. Indicating a longer hardbake at low temperature can increase the Rl, but the Rl increase is not as significant as increasing hardbake temperature to 200°C.

[0392] Gap fill wafers are fabricated to analyze differences of Ti and Nb precursor based formulations. Figure 2A shows SEM image of film sample of formulation 5 (Nb precursor) baked at 150 °C, figure 2B shows SEM image of film sample of formulation 6 (Nb precursor) baked at 150 °C, and figure 2C shows SEM image of film sample of formulation 7 (Nb precursor) baked at 150 °C. As can be seen in the figures, there is no improvement when

[0393] 30 using Nb based precursor compared to Ti based formulation. Most of the Foreignfiling text P24-206

[0394] - 43- materials is deposited on top of the trenches, only very little material enters the gap.

[0395] Working example 7: Methylsulfamic acid containing formulations 8 to

[0396] 5 13

[0397] Methylsulfamic acid containing formulations are prepared in the same manner as described in working example 1 , except that methylsulfamic acid are used instead of sulfamic acid, and Nb based precursor are used instead of Ti based precursor for formulations 11-13. The mixing ratio is indicated in below table 6.

[0398] Table 6

[0399] Working example 8: Forming films from formulations 8 to 13

[0400] Samples 29 to 46 are obtained in the same manner as described in working example 2 except that different formulations are used for all samples and

[0401] 30 different baking conditions are used for sample 30 (baking temperature 200°C / 5min), sample 31 (baking temperature 150°C / 30min), sample 33 Foreignfiling text P24-206

[0402] - 44-

[0403] (baking temperature 200°C / 5min), sample 34 (baking temperature 150°C / 30min), sample 36 (baking temperature 200°C / 5min), sample 37 (baking temperature 150°C / 30min), sample 39 (baking temperature 200°C / 5min), sample 40 (baking temperature 150°C / 30min), sample 42

[0404] 5 (baking temperature 200°C / 5min), sample 43 (baking temperature 150°C / 30min), sample 45 (baking temperature 200°C / 5min), sample 46 (baking temperature 150°C / 30min). The conditions and results are list in table 7.

[0405] Table 7

[0406] Table 7 shows that film samples made from formulations 10 and 13, which contain a very high concentration of the acid in solution, result in a reduction in refractive index (Rl) and the removal of the acid by

[0407] 30 decomposition is incomplete. However, based on the experimental results, it is considered that the use of strong acids that are more prone to thermal decomposition in this experiment reduces the negative effects associated Foreignfiling text P24-206

[0408] - 45- with the presence of acids remaining in the film compared to using acids that are less likely to decompose. Samples made from formulations 8, 9, 11 , 12, which contain moderate acid concentrations, the refractive indices (RIs) archived are high. And at the same hardbake temperature, longer

[0409] 5 hardback times can also help to obtain high Rl, as can be seen when comping samples 29, 32, 38, 41 (150°C / 5min) to samples 31 , 34, 40, 42 (150°C / 30min). It is inferred that the strong acids used in this experiment, which are more prone to thermal decomposition, allow for more pronounced improvements when reducing their usage or applying hardbake treatments at higher temperatures.

[0410] Gap fill wafers of methylsulfamic acid containing formulations are fabricated to analyze the effects of concentration of acids on samples. Figures 3A, 3B and 3C show SEM images of film samples from methylsulfamic acid

[0411] 15 containing formulation (Nb precursor) at 0.2, 1 and 4.x wt% acid, and figures 4A, 4B and 4C show SEM images of film samples from methylsulfamic acid containing formulation (Ti precursor) at 0.2, 1 and 4.x wt% acid. The figures illustrate that as the concentration of the acid increases, the gap fill properties also improve.

[0412] 20

[0413] 30

Claims

Foreignfiling text P24-206- 46-Claims1 . Formulation for preparing an optical layer containing a metal oxide, preferably for preparing a composite, more preferably for preparing a5 layered composite, comprising at least;(i) a metal alkoxide, preferably said metal alkoxide contains a group 4 and / or group 5 element of the periodic table; and(ii) an acid represented by the following chemical formula (la):X-Y-ZR1R2- (la) wherein,X is -SO3H or -PO3H;Y is 0, direct bond, alkylene group having 1 to 25 carbon atoms, aryl group15 having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I,20 CN or NO2; where each of groups may be substituted by one or more groups Rax;Rax is at each occurrence, 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 group or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon30 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; where in each of the above-mentioned groups, one or more HForeignfiling text P24-206- 47- atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another;Z is nitrogen atom;5 R1is H, 0, alkyl group having 1 to 25 carbon atoms; aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non- adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;Raxis at each occurrence, 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 cyclic15 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 group or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon20 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another;R2is H, O, alkyl group having 1 to 25 carbon atoms; aryl group having 3 to 25 carbon atoms, alkyl aryl group having 4 to 25 carbon atoms, a cyclic alkyl or alkoxy group having 3 to 25 carbon atoms; where one or more non- adjacent CH2 groups of the above-mentioned groups may be replaced by30 oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;Foreignfiling text P24-206- 48-Raxis at each occurrence, 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 105 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 group 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another.

152. Formulation of claim 1 , wherein said acid is selected from one or more members of the group consisting of sulfamic acids, amino phosphonates and nitrogen containing sulfonic acids, preferably nitrogen containing sulfonic acids is amino sulfonic acid and nitro aromatic sulfonic acids.

203. Formulation of claim 1 or 2, wherein said acid is a sulfamic acid represented by following chemical formula (I), an amino phosphonate represented by following chemical formula (II), an amino sulfonic acid represented by following chemical formula (III), or a nitro aromatic sulfonic acid represented by the following chemical formular (IV):Ra1Ra1NSO3H - (I) wherein,Ra1is, each independently, H, a straight-chain alkyl group having 1 to 2530 carbon atoms, preferably 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms; a branched or cyclic alkyl group having 3-25 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; anForeignfiling text P24-206- 49- aryl group having 3 to 25 carbon atoms, preferably from 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; a straight chain alkylcycloalkyl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; branched chain alkyl-cycloalkyl group having carbon atoms 6 to 255 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; branched chain alkyl-aryl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;Rax is at each occurrence, identically or differently, H, D, a straight chain alkyl or alkoxy group having 1 to 15 carbon atoms, preferably 1 to 1015 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 group or20 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another;PO3H2Ra2NRa1Ra1- (II) wherein,30 Ra1is, each independently, H, 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 3-25 carbon atoms,Foreignfiling text P24-206- 50- preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; an aryl group having 3 to 25 carbon atoms, preferably from 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; a straight chain alkylcycloalkyl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon5 atoms; branched chain alkyl-cycloalkyl group having carbon atoms 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; branched chain alkyl-aryl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;Rax is at each occurrence, identically or differently, H, D, a straight chain15 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 carbon20 atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl group 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another;Ra2is, each independently, selected from a straight-chain alkyl group having 1 to 25 carbon atoms, preferably 1 to 15 carbon atoms, more30 preferably 1 to 10 carbon atoms; a branched or cyclic alkyl group having 3- 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 from 3Foreignfiling text P24-206- 51- 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; branched chain alkyl-cycloalkyl group having carbon atoms 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; a straight chain5 alkyl-aryl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; branched chain alkyl-aryl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax; Rax is at each occurrence, identically or differently, H, D, a straight chain alkyl or alkoxy group having 1 to 15 carbon atoms, preferably 1 to 1015 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 group or20 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another;NH2Ra2SO3H- (III) wherein,30 Ra2is, each independently, selected from 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-Foreignfiling text P24-206- 52-25 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 from 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 155 carbon atoms; branched chain alkyl-cycloalkyl group having carbon atoms 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; branched chain alkyl-aryl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;15 Rax is at each occurrence, 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 alkenyl20 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 group 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another;30 SO3HRa3NO2- (IV) wherein,Foreignfiling text P24-206- 53-Ra3is an aryl group having 3 to 25 carbon atoms, preferably from 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms, where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH5 and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax; Rax is at each occurrence, 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 group or alkynyl group having 3 to 15 carbon atoms, preferably 3 to 10 carbon15 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic20 ring system with one another.

4. Formulation of any one of preceding claims, wherein said metal alkoxide is represented by following chemical formula (V) or formula (VI): Mb1O4(Rb1Rb2Rb3Rb4) -(V) Mb2O5(Rb1Rb2Rb3Rb4Rb5) -(VI)Rb1, Rb2, Rb3, Rb4and Rb5are each 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 cyclic30 alkyl group having 3-25 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 from 3 to 15 carbon atoms, more preferably 3 to 10Foreignfiling text P24-206- 54- carbon atoms; a straight chain alkyl-cycloalkyl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon atoms; branched chain alkyl-cycloalkyl group having carbon atoms 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; a straight chain alkyl-aryl group having 4 to 25 carbon atoms,5 preferably 4 to 15 carbon atoms; branched chain alkyl-aryl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, where each of groups may be substituted by one or more groups Ra; Rais at each occurrence, 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 alkenyl15 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 group 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 aromatic20 ring atoms; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Ra here may optionally form a mono- or polycyclic, aliphatic ring system with one another.

5. Formulation of any one of preceding claims, wherein said acid is a sulfamic acid represented by following chemical formula (I):Ra1Ra1NSO3H - (I) wherein,30 Ra1is, each independently, H, 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 3-25 carbon atoms,Foreignfiling text P24-206- 55- preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; an aryl group having 3 to 25 carbon atoms, preferably from 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms; a straight chain alkylcycloalkyl group having 4 to 25 carbon atoms, preferably 4 to 15 carbon5 atoms; branched chain alkyl-cycloalkyl group having carbon atoms 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; branched chain alkyl-aryl group having 6 to 25 carbon atoms, preferably 6 to 15 carbon atoms; where one or more non-adjacent CH2 groups of the above-mentioned groups may be replaced by oxygen atom, C=O, C=S, C=Se, C=NH, SiH2, SO, SO2, OS, or CONH and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2; where each of groups may be substituted by one or more groups Rax;Rax is at each occurrence, identically or differently, H, D, a straight chain15 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 carbon20 atoms, more preferably 2 to 5 carbon atoms; a branched alkenyl group 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; where in each of the above-mentioned groups, one or more H atoms may be replaced by D, F, Cl, Br, I, and where two or more adjacent substituents Raxhere may optionally form a mono- or polycyclic, aliphatic ring system with one another.

6. Formulation of any one of preceding claims, wherein said acid is a30 methyl sulfamic acid represented by following chemical formula (I1):CH3H2NSO3 - (I1)Foreignfiling text P24-206- 56-7. Formulation of any one of preceding claims, contains a solvent selected from acidic water having hydrogen ion index (pH) below 7 and 1 or more, preferably 1 ^pH<7, or an organic solvent or a mixture of water and one5 more of 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 members of the group consisting of ethylene glycol monoalkyl ethers, preferably it is ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether and / or ethylene glycol monobutyl ether; diethylene glycol dialkyl ethers, preferably it is diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether and / or diethylene glycol dibutyl ether; propylene glycol monoalkyl ethers, preferably it is propylene glycol monomethyl ether (PGME), propylene15 glycol monoethyl ether and / or propylene glycol monopropyl ether; 1 ,3- dimethoxy-2-propanol, ethylene glycol alkyl ether acetates, preferably it is methyl cellosolve acetate and / or ethyl cellosolve acetate; propylene glycol alkyl ether acetates, preferably it is propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate and / or20 propylene glycol monopropyl ether acetate; ketones, preferably it is methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone and / or cyclohexanone; alcohols, preferably it is ethanol, propanol, butanol, hexanol, cyclo hexanol, ethylene glycol, propylene glycol, triethylene glycol and / or glycerin; esters, preferably it is ethyl 3-ethoxypropionate, methyl 3- methoxypropionate and / or ethyl lactate; and cyclic esters, preferably it is gamma-butyro-lactone; preferably said solvent is ethylene glycol monoalkyl ethers, diethylene glycol dialkyl ethers, propylene glycol, ethylene glycol, propylene glycol monoalkyl ethers, ethylene glycol alkyl ether acetates, propylene glycol alkyl ether acetate, more preferably said solvent is30 selected from propylene glycol alkyl ether acetates, ethylene glycolForeignfiling text P24-206- 57- monoalkyl ethers, propylene glycol and propylene glycol monoalkyl ethers, 1 ,3-dimethoxy-2-propanol.

8. Method for preparing a formulation of any one of the preceding claims,5 containing at least the following step;(X) mixing a metal alkoxide, preferably said metal alkoxide contains a group 4 and / or group 5 element of the periodic table; an acid of formula (la); and optionally, a solvent selected from water, preferably acidic water having hydrogen ion index (pH) below 7 and 1 or more, preferably 1 ^pH<7, an organic solvent or a mixture of said water and one more organic solvent, is also mixed in step (X).

9. Method for preparing a composite containing a metal oxide; comprising15 the following steps (a) and (b):(a) providing the formulation of any one of claims 1 to 7 onto a surface of a substrate, preferably by wet deposition process, more preferably by spincoating or ink-jetting, even more preferably by ink-jetting; and(b) applying a thermal treatment to the formulation provided on the surface20 of the substrate to convert at least a part of the metal alkoxide of the formulation to a metal oxide, preferably said composite being a layered composite, more preferably said layered composite is an optical layer, optionally in step (a), the formulation is applied to a surface of a substrate by spin-coating or ink-jetting, optionally, said substrate is being a patterned substrate comprising topographical features on the surface thereof.

10. Method of claim 9, wherein in step (b), the formulation is at least partly converted on the surface of the substrate to a composite, preferably it is being of a layered composite, by baking it at a temperature from 100 to30 600 °C, preferably it is from 125 to 450°C, more preferably from 150 to 250°C.Foreignfiling text P24-206- 58-11 . Method of claim 9 or 10, wherein the formulation is at least partly converted on the surface of the substrate to a composite, wherein said composite contains a metal oxide, preferably selected from metal dioxide5 and / or metal mono oxide; and a metal alkoxide.

12. A composite, preferably being a layered composite, preferably said layered composite is an optical layer, obtained from the method of claim 9 or 10, or derived from the formulation of any one of claims 1 to 7.

13. An optical device comprising the composite of claim 12, and a substrate comprising a patterned surface or an uneven surface, preferably a gap or trench of said patterned surface or an uneven surface of the substrate is at least partly filled with said composite, preferably said substrate is a15 patterned substrate comprising topographical features on the surface thereof14. The optical device of claim 13, wherein said composite of claim 12 fills at least a part of a gap of said topographical features, more preferably said20 composite fills a trench of the patterned substrate.

15. A display device comprising at least one functional medium configured to direct and modulate a light or configured to emit light; and the composite of claim 12, or an optical device of claim 13 or 14.30

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