Method for forming a coating

Abstract

A chemical vapor deposition process is provided for forming a nickel oxide-based layer on a glass substrate. A gaseous mixture is formed, which comprises a nickel-containing compound selected from the group consisting of nickel(II) acetylacetonate and its derivatives, and an oxygen-containing precursor selected from the group consisting of carbonyl compounds and molecular oxygen. The gaseous mixture is directed towards and along the glass substrate and reacts on the glass substrate to form a nickel oxide coating thereon.

Description

Technical Field

[0001] The present invention generally relates to a process for forming a nickel oxide-based coating or layer. In particular, the present invention relates to a chemical vapor deposition (CVD) process for forming a nickel oxide-based coating on a glass substrate.

Summary of the Invention

[0002] Embodiments of a chemical vapor deposition process for forming a nickel oxide coating are described below. In one embodiment, the chemical vapor deposition process for forming a nickel oxide coating includes providing a glass substrate, preferably a moving glass substrate. A gaseous mixture is formed that includes a nickel-containing compound and one or more oxygen-containing precursors. The nickel-containing compound is preferably one or more of nickel(II) acetylacetonate and its derivatives. The one or more oxygen-containing precursors are preferably selected from the group consisting of carbonyl compounds and molecular oxygen.

[0003] The gaseous mixture is directed toward and along the glass substrate. The gaseous mixture reacts on the glass substrate to form a nickel oxide coating on the glass substrate.

[0004] In some embodiments, the glass substrate is a glass ribbon in a float glass manufacturing process.

[0005] In some embodiments, the nickel oxide coating is formed on the deposition surface of the glass substrate that is substantially at atmospheric pressure.

[0006] In some embodiments, the method further includes preparing a coating apparatus and supplying the gaseous mixture to the coating apparatus before forming the nickel oxide coating on the glass substrate.

[0007] The nickel oxide coating can be formed on the deposition surface of the glass substrate that is substantially at atmospheric pressure when the gaseous mixture reacts to form the nickel oxide coating.

[0008] Embodiments may exist where a nickel oxide coating is formed on top of a coating pre-formed on the glass substrate. Thus, in some embodiments, the nickel oxide coating is formed on top of a silicon oxide and / or tin oxide-based coating pre-formed on the glass substrate. In some embodiments, the nickel oxide coating is formed on top of a transparent conductive oxide (TCO) coating such as, for example, a fluorine-doped tin oxide or indium tin oxide pre-formed on the glass substrate. In certain preferred embodiments, the TCO is a coating based on fluorine-doped tin oxide. The nickel oxide coating may preferably be deposited on top of a TCO coating deposited on top of a silicon oxide-based coating deposited on the glass substrate. In certain embodiments, the nickel oxide coating is the outermost layer coating of a coating stack provided on the glass substrate.

[0009] In some embodiments, when the nickel oxide coating is formed thereon, the temperature of the glass substrate is between 1000°F (538°C) and 1400°F (760°C), and the nickel oxide coating is thermally decomposable.

[0010] In certain preferred embodiments, the nickel-containing compound is one or more of nickel(II) acetylacetonate, bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II), nickel(II) hexafluoroacetylacetonate, and nickel(II) trifluoroacetylacetonate. Commercially available nickel(II) hexafluoroacetylacetonate is always hydrated, and the number of H2O molecules is unknown or variable, while commercially available nickel(II) trifluoroacetylacetonate is dihydrated. In a preferred embodiment, the nickel-containing compound is bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II).

[0011] In embodiments, the oxygen-containing precursor is included in a gaseous mixture composed of one or more carbonyl compounds. In certain embodiments, the carbonyl compound is an ester, and further, the ester can have an alkyl group having β-hydrogen. The oxygen-containing precursor can be one or more of ethyl acetate, ethyl formate, ethyl propionate, isopropyl formate, isopropyl acetate, n-butyl acetate, and t-butyl acetate. In a preferred embodiment, the oxygen-containing precursor is ethyl acetate.

[0012] In some embodiments, the gaseous mixture is composed of molecular oxygen. In certain particularly preferred embodiments, the gaseous mixture is composed of a carbonyl compound, particularly ethyl acetate, and molecular oxygen.

[0013] In a particularly preferred embodiment, the gaseous mixture is composed of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II), molecular oxygen, and ethyl acetate.

[0014] Preferably, the ratio of oxygen to nickel in the nickel oxide coating is at least 0.5, more preferably at least 0.6, even more preferably at least 0.7, but preferably at most 1.2, more preferably at most 1.0, even more preferably at most 0.9. The ratio of oxygen to nickel in the nickel oxide coating can be measured by XPS.

[0015] Preferably, the gaseous mixture contains at least 0.3 vol% of nickel-containing compounds, more preferably at least 0.4 vol% of nickel-containing compounds, even more preferably at least 0.5 vol% of nickel-containing compounds, but preferably contains at most 5.0 vol% of nickel-containing compounds, more preferably at most 2.0 vol% of nickel-containing compounds, even more preferably at most 1.0 vol% of nickel-containing compounds.

[0016] Preferably, the gaseous mixture contains at least 3.0 vol% of oxygen-containing precursors, more preferably at least 4.0 vol% of oxygen-containing precursors, even more preferably at least 5.0 vol% of oxygen-containing precursors, but preferably contains at most 20.0 vol% of oxygen-containing precursors, more preferably at most 12.0 vol% of oxygen-containing precursors, even more preferably at most 10.0 vol% of oxygen-containing precursors.

[0017] The above, and other advantages of the present process, will become readily apparent to those skilled in the art upon consideration of the following detailed description in light of FIG. 1 in the accompanying drawings, which is a schematic view of a vertical cross-section of a facility for implementing a float glass manufacturing process according to an embodiment of the present invention.

Brief Description of the Drawings

[0018]

Figure 1

Embodiments for Carrying Out the Invention

[0019] It should be understood that the present invention can envision various alternative directions and step sequences, unless explicitly provided to the contrary. It should also be understood that the specific coated glass substrates, devices, and processes described in the following specification are merely exemplary embodiments of the concepts of the present invention. Therefore, specific dimensions, directions, or other physical characteristics associated with the disclosed embodiments should not be considered limiting unless explicitly stated otherwise. Also, although it may not always be the case, similar elements in the various embodiments described within this section of the application may generally be referred to by similar reference numerals.

[0020] In the context of the present invention, when a layer or coating is said to be "based on" a particular material or materials, this means that the layer or coating consists primarily of the corresponding material or materials, and typically means that the material or materials are present in an amount of at least about 50 atomic %.

[0021] In the following description of the present invention, unless otherwise indicated, the disclosure of alternative values of the upper or lower limits of the tolerance range of a parameter, in conjunction with an indication that one of the values is more preferred than the other, is to be construed as implicitly indicating that each intermediate value of the parameter between the more preferred and less preferred of the alternative values is itself more preferred than the less preferred value, and more preferred than each value between the less preferred value and the intermediate value.

[0022] Throughout this specification, the terms "comprising" or "including" mean including the specified components, but do not exclude the presence of other components. The terms "consisting essentially of" or "consisting essentially of" mean including the specified components, but excluding substances present as impurities, inevitable substances present as a result of the processes used to provide the components, and components other than those added for purposes other than achieving the technical effects of the invention. Usually, when referring to a composition, a composition consisting essentially of a set of components contains less than 5% by weight, typically less than 3% by weight, and more typically less than 1% by weight of unspecified components.

[0023] The terms "consisting of" or "consisting of" mean including the specified components, but excluding other components.

[0024] Whenever appropriate and depending on the context, the use of the terms "comprising" or "including" may be interpreted as also including the meaning of "consisting essentially of" or "consisting essentially of", and may also be interpreted as including the meaning of "consisting of" or "consisting of".

[0025] References such as "in the range from x to y" here are intended to include the interpretation of "from x to y", and thus the values x and y are included.

[0026] In the context of the present invention, a transparent material or a transparent substrate is a material or a substrate that can transmit visible light, and as a result, an object or an image on the other side or the back side of the material can be clearly seen through the material or the substrate.

[0027] In the context of the present invention, the "thickness" of a layer is represented by the distance through the layer from the position of the surface of the layer at any given position to the position of the opposite surface of the layer in the direction of the minimum dimension of the layer.

[0028] In the present invention, a "derivative" is a chemical substance that is structurally related to another chemical substance and can theoretically be derived therefrom.

[0029] In one embodiment of the present invention, a CVD process (hereinafter also referred to as the "CVD process") for forming a nickel oxide coating is provided. The CVD process is described in relation to a coated glass substrate. Such a coated glass substrate can be used for various applications. For example, the coated glass substrate can be used in solar cells, architectural glass, electronic devices, and / or automotive and aerospace applications, but is not limited thereto. The coated glass substrate has NiO x functioning as a buffer layer material, and can be particularly advantageous as a substrate in perovskite solar cells.

[0030] The nickel oxide coating contains nickel and oxygen. In certain embodiments, the nickel oxide coating can consist essentially of nickel and oxygen. The nickel oxide coating can also contain one or more additional components in trace amounts, such as carbon for example. As used herein, the phrase "trace amount" means that the amount of the component of the nickel oxide-based layer is less than 0.01 wt%, or equivalently less than 100 ppm.

[0031] The CVD process can be carried out in conjunction with the manufacture of the glass substrate. In one embodiment, the glass substrate can be formed using a known float glass manufacturing process. An example of a float glass manufacturing process is shown in FIG. 1. In this embodiment, the glass substrate can also be referred to as a glass ribbon. However, it should be understood that the CVD process can be used separately from the float glass manufacturing process or even considerably after the formation and cutting of the glass ribbon.

[0032] In certain embodiments, the CVD process is a dynamic deposition process. In these embodiments, the glass substrate is moving when the nickel oxide coating is being formed. Preferably, when the nickel oxide coating is being formed, the glass substrate moves at a predetermined speed that exceeds, for example, 3.175 m / min (125 inches / min). In one embodiment, when the nickel oxide coating is being formed, the glass substrate moves at a speed of 3.175 m / min (125 inches / min) to 12.7 m / min (600 inches / min).

[0033] In certain embodiments, the glass substrate is heated. In one embodiment, the temperature of the glass substrate when the nickel oxide coating is being formed is about 1000°F (538°C) or higher. In another embodiment, the temperature of the glass substrate when the nickel oxide coating is formed thereon is about 1000°F (538°C) to 1400°F (760°C).

[0034] Preferably, the nickel oxide coating is deposited on the deposition surface of the glass substrate while the deposition surface of the glass substrate is substantially at atmospheric pressure. In this embodiment, the CVD process is an atmospheric pressure CVD (APCVD) process. However, the CVD process is not limited to the APCVD process, and in other embodiments, the nickel oxide coating can be formed under low pressure conditions.

[0035] The glass substrate is not limited to any particular thickness. Also, the glass substrate can be a conventional glass composition known in the art. In one embodiment, the glass substrate is soda lime silica glass. In some embodiments, the substrate can be part of a float glass ribbon. However, the CVD process is not limited to soda lime silica glass substrates, and in other embodiments, the glass substrate can be, for example, borosilicate glass or aluminosilicate glass.

[0036] In addition, the transparency or absorption characteristics of the glass substrate can vary between embodiments. Further, the color of the glass substrate can vary between embodiments of the CVD process. In one embodiment, the glass substrate can be substantially transparent. In other embodiments, the glass substrate can be lightly colored or colored.

[0037] The nickel oxide coating can be deposited by providing one or more nickel-containing compounds selected from nickel(II) acetylacetonate and its derivatives, preferably nickel(II) acetylacetonate, bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II), nickel(II) hexafluoroacetylacetonate, and nickel(II) trifluoroacetylacetonate, and one or more oxygen-containing molecules selected from the group consisting of carbonyl compounds and molecular oxygen.

[0038] Separate supply lines can extend from a source of reactant (precursor) molecules. The terms "reactant molecule" and "precursor molecule" as used herein are used interchangeably to refer to any or all of the nickel-containing compounds and oxygen-containing molecules and / or to describe the various embodiments disclosed herein. Preferably, the source of precursor molecules is provided at a location outside the float bath chamber.

[0039] Preferably, the nickel oxide coating is deposited by forming a gaseous mixture. The precursor molecules used to form the gaseous mixture are preferably suitable for use in a CVD process. Such molecules can be liquid or solid at some point but are volatile and thus can be vaporized and used in the gaseous mixture. In certain embodiments, the gaseous mixture contains precursor molecules suitable for forming a nickel oxide coating at substantially atmospheric pressure. When in the gaseous state, the precursor molecules can be included in a gas stream and utilized for the formation of the nickel oxide coating.

[0040] In some embodiments, the gaseous mixture formed to deposit the nickel oxide coating includes oxygen-containing molecules composed of carbonyl compounds. In these embodiments, the carbonyl compound is preferably an ester. More preferably, the carbonyl compound is an ester having an alkyl group with β-hydrogen. An alkyl group having β-hydrogen and containing 2 to 10 carbon atoms is preferred. Even more preferably, the ester is selected from one or more of ethyl acetate (EtOAc), ethyl formate, ethyl propionate, isopropyl formate, isopropyl acetate, n-butyl acetate, and t-butyl acetate. Most preferably, the oxygen-containing compound is ethyl acetate. In certain preferred embodiments, the gaseous mixture includes molecular oxygen in addition to a carbonyl compound such as ethyl acetate.

[0041] The gaseous mixture may also include one or more inert gases used as a carrier gas or diluent gas. Suitable inert gases include nitrogen (N2), helium (He), and mixtures thereof. Accordingly, a source of one or more inert gases may be provided from which a separate supply line may extend.

[0042] The precursor molecules are mixed to form a gaseous mixture. In certain embodiments, a coating apparatus may be provided. Preferably, the gaseous mixture is supplied to the coating apparatus before forming a nickel oxide coating on the glass substrate. The gaseous mixture may be discharged from the coating apparatus using one or more gas distribution beams. Preferably, the gaseous mixture is formed before being supplied to the coating apparatus. For example, the precursor molecules may be mixed in a supply line connected to the inlet of the coating apparatus. In other embodiments, the gaseous mixture may be formed within the coating apparatus and before the coating apparatus exists.

[0043] Preferably, the coating device extends across the entire glass substrate and is provided at a predetermined distance above the glass substrate. The coating device is arranged at at least one predetermined position. When using the CVD process in combination with the float glass manufacturing process, the coating device is preferably provided in the float bath section. However, the coating device can be provided in the annealing furnace and / or in the gap between the float bath and the annealing furnace.

[0044] The gaseous mixture is directed towards and along the glass substrate. When using the coating device, the gaseous mixture is sent towards and along the glass substrate. Preferably, the gaseous mixture is directed towards and along the glass substrate in a laminar flow.

[0045] The gaseous mixture reacts on or near the glass substrate to form a nickel oxide coating thereon. In some embodiments, the nickel oxide coating is pyrolytic. The term "pyrolytic" as used herein can refer to a coating that is chemically bonded to the glass substrate.

[0046] The nickel oxide coating of the present invention can be formed on one or more pre-deposited coatings. For example, the nickel oxide coating can be formed on a pre-deposited silicon oxide coating formed on the deposition surface of a glass substrate. The nickel oxide coating can be formed directly on the silicon oxide coating. In other embodiments, the nickel oxide coating can be formed on a pre-deposited tin oxide coating formed on the deposition surface of a glass substrate. In these embodiments, the tin oxide coating may or may not be doped, and when the tin oxide coating is doped, it can be doped with fluorine. In some embodiments, a nickel oxide coating is formed on a pre-formed TCO coating on a glass substrate. In certain preferred embodiments, the TCO is a coating based on, for example, fluorine-doped tin oxide. The nickel oxide coating may preferably be deposited on a TCO coating deposited on a silicon oxide-based coating deposited on a glass substrate. The nickel oxide coating can be formed directly on a tin oxide or other TCO coating. In certain embodiments, the nickel oxide coating is the outermost coating of a coating stack provided on a glass substrate.

[0047] In certain preferred embodiments, the glass substrate is provided with a coating stack comprising, or preferably consisting of, in order from the deposition surface of the glass substrate, a silicon oxide-based coating, a tin oxide-based coating, and a nickel oxide-based coating. In these embodiments, the tin oxide-based coating may or may not be doped.

[0048] In other preferred embodiments, the glass substrate is provided with a coating stack comprising, or preferably consisting of, in order from the deposition surface of the glass substrate, a silicon oxide-based coating and a nickel oxide-based coating.

[0049] As described above, the nickel oxide coating can be formed simultaneously with the production of the glass substrate in a known float glass manufacturing process. The float glass manufacturing process is typically carried out using float glass equipment such as the equipment 30 shown in FIG. 1. However, it should be understood that the float glass equipment 30 described herein is merely an example of such equipment.

[0050] As shown in FIG. 1, the float glass equipment 30 may include a canal section 32 along which the molten glass 34 is conveyed from the melting furnace to a float bath section 36 where the glass substrate is formed. In this embodiment, the glass substrate is referred to as a glass ribbon 38. The glass ribbon 38 is a preferred substrate on which the nickel oxide coating is formed. However, it should be understood that the glass substrate is not limited to the glass ribbon.

[0051] In an embodiment of the present invention, the glass ribbon 38 advances from the bath section 36 through an adjacent annealing furnace 40 and a cooling section 42. The float bath section 36 includes a bottom section 44 containing a bath 46 of molten tin, a roof 48, an opposite side wall (not shown), and end walls 50, 52. The roof 48, side walls, and end walls 50, 52 together define an enclosure 54 within which a non-oxidizing atmosphere is maintained to prevent oxidation of the molten tin 46.

[0052] During operation, the molten glass 34 flows along the canal 32 under the regulating tool 56 and then flows downward toward the surface of the tin bath 46 in a controlled amount. At the surface of the molten tin, the molten glass 34 spreads laterally under the influence of gravity, surface tension, and certain mechanical effects, travels across the tin bath 46, and forms the glass ribbon 38. The glass ribbon 38 is removed from the bath section 36 via the lift-out roll 58 and then conveyed through the annealing furnace 40 and the cooling section 42 on aligned rolls. The deposition of the nickel oxide coating is preferably carried out in the float bath section 36, but it may also be possible to carry out the deposition further downstream in the glass manufacturing line, for example in the gap 60 between the float bath 36 and the annealing furnace 40, or within the annealing furnace 40.

[0053] As shown in FIG. 1, the coating device 62 is provided within the float bath section 36. The nickel oxide coating can be formed using the coating device 62. In this embodiment, the nickel oxide coating can be formed directly on the glass substrate. In certain embodiments, the nickel oxide coating can be formed on top of one or more coatings pre-formed on the glass ribbon 38. These coatings can each be formed using a separate coating device. For example, in one embodiment, a coating layer containing silicon oxide can be deposited using the coating devices 62, 64. In this embodiment, the nickel oxide coating is located downstream of the coating devices 62, 64 used to form the tin oxide coating and can be formed directly on or on top of the silicon oxide coating using another coating device provided within the float bath section 36 or another part of the float glass facility 30. In another embodiment, a coating device 66 can be provided and used to form a coating containing fluorine-doped tin oxide. In this embodiment, the nickel oxide coating can be formed directly on or on top of the doped tin oxide coating using a coating device 68 located downstream of the coating device 66.

[0054] In the float bath section 36, a suitable non-oxidizing atmosphere, generally nitrogen or a mixture of nitrogen and hydrogen with nitrogen as the main component, is maintained to prevent oxidation of the molten tin 46 that constitutes the float bath. The atmosphere gas is introduced through a conduit 70 operably connected to the distribution manifold 72. The non-oxidizing gas is introduced at a rate sufficient to compensate for normal losses and maintain a slight positive pressure about 0.001 to about 0.01 atmospheres higher than the ambient atmospheric pressure, preventing the ingress of external air. For the purposes of the description of the present invention, the above pressure range is considered to constitute normal atmospheric pressure.

[0055] Preferably, the nickel oxide coating is formed substantially at atmospheric pressure. Thus, the pressure in the float bath section 36, the annealing furnace 40, and / or the gap 60 between the float bath section 36 and the annealing furnace 40 can be substantially at atmospheric pressure.

[0056] Heat for maintaining the desired temperature conditions in the float bath section 36 and the enclosure 54 can be provided by a radiant heater 74 within the enclosure 54. Since the cooling section 42 is not sealed, the atmosphere within the lehr 40 is usually air, and the glass ribbon 38 is open to the ambient air. Thereafter, the glass ribbon 38 can be cooled to ambient temperature. To cool the glass ribbon 38, ambient air can be directed at the glass ribbon 38 by a fan 76 in the cooling section 42 or the like. Also, a heater (not shown) can be provided within the annealing furnace 40 to gradually lower the temperature of the glass ribbon 38 according to predetermined conditions as the glass ribbon 38 passes therethrough.

Example

[0057] The following examples are presented only for the purpose of further illustrating and disclosing embodiments of the process for depositing a nickel oxide coating in accordance with the present invention and should not be construed as limiting the present invention.

[0058] Example 1 is the deposition of a nickel oxide coating directly deposited by a lab coater on a thermally decomposable silicon oxide coating pre-formed on a glass substrate. The glass substrate is of the soda lime silica type, has a thickness of 3.2 mm, and was moving at a line speed of 75 inches / min when the nickel oxide coating was deposited. The nickel oxide coating was deposited by forming a gaseous mixture of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II) and molecular oxygen. Bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II) was prepared as 20 wt% in a trimethylamine solution at a flow rate of 18.0 cc / min. These precursors were mixed to form a gaseous mixture and then fed to a lab coating apparatus before being directed towards and along the glass substrate. The estimated gas phase concentrations were 0.50 vol% for bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II) and 5.00 vol% for molecular oxygen, with the balance being nitrogen. A uniform coating of nickel oxide was formed on the glass substrate at a deposition rate of 1.5 nm / sec, and the thickness of the coating was determined to be 100 Å by a scanning electron microscope (SEM). The ratio of oxygen to nickel in the coating was measured to be 0.7 by X-ray photoelectron spectroscopy (XPS). The coated glass substrate of Example 1 was measured to have a light transmittance of 90.76% and a film-side reflectance of 8.23%. The light transmittance and film-side reflectance of each example were measured using a UV-Vis-NIR spectrometer with a wavelength range of 380 nm to 780 nm.

[0059] Example 2 is the deposition of a nickel oxide coating directly deposited by a lab coater on a thermally decomposable silicon oxide coating pre-formed on a glass substrate. The glass substrate is of the soda-lime-silica type, has a thickness of 3.2 mm, and was moving at a line speed of 75 inches / min when the nickel oxide coating was deposited. The nickel oxide coating was deposited by forming a gaseous mixture of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II), ethyl acetate, and molecular oxygen. Bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II) was prepared as 20 wt% in a trimethylamine solution at a flow rate of 18.0 cc / min. These precursors were mixed to form a gaseous mixture and then fed to a lab coating apparatus before being directed towards and along the glass substrate. The estimated gas phase concentrations were 0.50 vol% for bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II), 5.00 vol% for ethyl acetate, and 5.00 vol% for molecular oxygen, with the balance being nitrogen. A uniform coating of nickel oxide was formed on the glass substrate, and the thickness of the coating was determined to be 100 Å by scanning SEM. The ratio of oxygen to nickel in the coating was measured to be 0.7 by XPS. The coated glass substrate of Example 2 was measured to have a light transmittance of 91.21% and a reflectance on the film side of 8.11%.

[0060] Example 3 is the deposition of a nickel oxide coating deposited using a lab coater on a coated glass substrate commercially available from Nippon Sheet Glass Co., Ltd. as NSG TEC 15TM. Thus, the substrate had a glass / SiO2 / SnO2 / SnO2:F layer, and the nickel oxide coating was deposited directly on a pyrolytic fluorine-doped tin oxide coating pre-formed on the glass substrate. The glass substrate was of the soda lime silica type, had a thickness of 3.2 mm, and was moving at a line speed of 75 inches / min when the nickel oxide coating was deposited. The nickel oxide coating was deposited by forming a gaseous mixture of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II) and molecular oxygen. Bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II) was prepared as 20 wt% in a trimethylamine solution at a flow rate of 18.0 cc / min. These precursors were mixed to form a gaseous mixture and then fed to a lab coating apparatus before being directed towards and along the glass substrate. The estimated gas phase concentrations were 0.50 vol% for bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II) and 5.00 vol% for molecular oxygen, with the balance being nitrogen. A discontinuous nickel oxide coating was formed on the glass substrate. The coated glass substrate of Example 3 was measured to have a light transmittance of 83.92% and a reflectance on the film side of 11.72%.

[0061] Example 4 is the deposition of a nickel oxide coating directly deposited with a lab coater on a thermally decomposable silicon oxide coating pre-formed on a glass substrate. The glass substrate was a soda-lime-silica type, had a thickness of 3.2 mm, and was stationary during the 15-second deposition. The nickel oxide coating was deposited by forming a gaseous mixture of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II), ethyl acetate, and molecular oxygen. Bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II) was prepared as 20 wt% in a trimethylamine solution at a flow rate of 18.0 cc / min. These precursors were mixed to form a gaseous mixture and then fed to a lab coating apparatus before being directed towards and along the glass substrate. The estimated gas phase concentrations were 0.80 vol% for bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II), 5.00 vol% for ethyl acetate, and 5.00 vol% for molecular oxygen, with the balance being nitrogen. A uniform coating of nickel oxide was formed on the glass substrate, and the thickness of the coating was determined to be 300 Å by optical modeling. The ratio of oxygen to nickel in the coating was measured to be 0.8 by XPS. The coated glass substrate of Example 3 was measured to have a light transmittance of 71.43% and a reflectance on the film side of 26.05%.

[0062] The foregoing description is to be considered merely illustrative of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desirable to limit the invention to the exact construction and process shown and described herein. Accordingly, all suitable modifications and equivalents are considered to be within the scope of the invention.

Claims

1. A chemical vapor deposition process for forming a nickel oxide coating on a glass substrate, The steps include preparing the glass substrate and The steps include forming a gaseous mixture comprising a nickel-containing compound selected from the group consisting of nickel(II) acetylacetonate and its derivatives, and an oxygen-containing precursor selected from the group consisting of carbonyl compounds and molecular oxygen, The steps of guiding the gaseous mixture toward and along the glass substrate, The steps include: reacting the gaseous mixture on the glass substrate to form a nickel oxide coating on the glass substrate; A chemical vapor deposition process that includes forming a nickel oxide coating on a glass substrate.

2. The chemical vapor deposition process according to claim 1, wherein the nickel-containing compound is selected from the group consisting of nickel(II) acetylacetonate, bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II), nickel(II) hexafluoroacetylacetonate, and nickel(II) trifluoroacetylacetonate.

3. The chemical vapor deposition process according to claim 1, wherein the nickel-containing compound is bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II).

4. The chemical vapor deposition process according to claim 1, wherein the oxygen-containing precursor is molecular oxygen.

5. The chemical vapor deposition process according to claim 1, wherein the oxygen-containing precursor is a carbonyl compound.

6. The chemical vapor deposition process according to claim 1, wherein the oxygen-containing precursor is an ester having an alkyl group having a β-hydrogen.

7. The chemical vapor deposition process according to claim 1, wherein the oxygen-containing precursor is one or more of ethyl acetate, ethyl formate, ethyl propionate, isopropyl formate, isopropyl acetate, n-butyl acetate, and t-butyl acetate.

8. The chemical vapor deposition process according to claim 1, wherein the oxygen-containing precursor is ethyl acetate.

9. The chemical vapor deposition process according to claim 1, wherein the gaseous mixture further comprises molecular oxygen.

10. The chemical vapor deposition process according to claim 1, wherein the glass substrate is a glass ribbon in a float glass manufacturing process.

11. The chemical vapor deposition process according to claim 1, further comprising preparing a coating apparatus and supplying the gaseous mixture to the coating apparatus before forming the nickel oxide coating on the glass substrate.

12. The chemical vapor deposition process according to claim 1, wherein the nickel oxide coating is formed on the deposition surface of a glass substrate at substantially atmospheric pressure when the gaseous mixture reacts to form the nickel oxide coating.

13. The chemical vapor deposition process according to claim 1, wherein the nickel oxide coating is formed on a coating previously formed on the glass substrate.

14. The chemical vapor deposition process according to claim 1, wherein the nickel oxide coating is formed on a silicon oxide-based coating that has been pre-formed on the glass substrate.

15. The chemical vapor deposition process according to claim 1, wherein the nickel oxide coating is formed on a tin oxide-based coating that has been pre-formed on the glass substrate.

16. The chemical vapor deposition process according to claim 15, wherein the tin oxide-based coating is doped with fluorine.

17. The chemical vapor deposition process according to claim 1, wherein the nickel oxide coating is formed on a tin oxide-based coating formed on a silicon oxide-based coating formed on the glass substrate.

18. The chemical vapor deposition process according to claim 1, wherein the glass substrate is at a temperature of 1000°F (538°C) to 1400°F (760°C) when the nickel oxide coating is formed thereon.

19. The chemical vapor deposition process according to claim 1, wherein the nickel oxide coating is thermally decomposable.

20. The chemical vapor deposition process according to claim 1, wherein the nickel oxide coating is an outermost coating stack on the surface of the glass substrate.

21. The chemical vapor deposition process according to claim 1, wherein the glass substrate is provided with a coating stack consisting of, in order from the glass substrate, a silicon oxide-based coating, a tin oxide-based coating, and a nickel oxide coating.

22. The chemical vapor deposition process according to claim 1, wherein the glass substrate is provided with a coating stack consisting of a silicon oxide-based coating and a nickel oxide coating, in that order from the glass substrate.

23. The chemical vapor deposition process according to claim 1, wherein the ratio of oxygen to nickel in the nickel oxide coating is at least 0.5, preferably at least 0.6, more preferably at least 0.7, but preferably up to 1.2, more preferably up to 1.0, and even more preferably up to 0.

9.

24. The chemical vapor deposition process according to claim 1, wherein the gaseous mixture contains at least 0.3 vol% of a nickel-containing compound, preferably at least 0.4 vol% of a nickel-containing compound, more preferably at least 0.5 vol% of a nickel-containing compound, but preferably up to 5.0 vol% of a nickel-containing compound, more preferably up to 2.0 vol% of a nickel-containing compound, and even more preferably up to 1.0 vol% of a nickel-containing compound.

25. The chemical vapor deposition process according to claim 1, wherein the gaseous mixture contains at least 3.0 vol% of an oxygen-containing precursor, preferably at least 4.0 vol% of an oxygen-containing precursor, more preferably at least 5.0 vol% of an oxygen-containing precursor, but preferably up to 20.0 vol% of an oxygen-containing precursor, more preferably up to 12.0 vol% of an oxygen-containing precursor, and even more preferably up to 10.0 vol% of an oxygen-containing precursor.

26. A coated glass substrate formed according to the chemical vapor deposition process described in claim 1.

27. A perovskite solar cell using a glass substrate formed according to the chemical vapor deposition process described in claim 1 or coated according to claim 26 as a buffer layer.

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