Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/15—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on an electrochromic effect
  • G02F1/1514—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on an electrochromic effect characterised by the electrochromic material, e.g. by the electrodeposited material
  • G02F1/1523—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on an electrochromic effect characterised by the electrochromic material, e.g. by the electrodeposited material comprising inorganic material
  • G02F1/1524—Transition metal compounds
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/15—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on an electrochromic effect
  • G02F1/153—Constructional details
  • G02F1/155—Electrodes
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/15—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on an electrochromic effect
  • G02F1/1506—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on an electrochromic effect caused by electrodeposition, e.g. electrolytic deposition of an inorganic material on or close to an electrode
  • G02F1/1508—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on an electrochromic effect caused by electrodeposition, e.g. electrolytic deposition of an inorganic material on or close to an electrode using a solid electrolyte
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/15—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on an electrochromic effect
  • G02F2001/1502—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on an electrochromic effect complementary cell
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/15—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on an electrochromic effect
  • G02F1/153—Constructional details
  • G02F1/155—Electrodes
  • G02F2001/1555—Counter electrode

Definitions

• Electrochromism is a phenomenon in which a material exhibits a reversible electrochemically-mediated change in an optical property when placed in a different electronic state, typically by being subjected to a voltage change.
• the optical property is typically one or more of color, transmittance, absorbance, and reflectance.
• One well known electrochromic material is tungsten oxide (WO3).
• Tungsten oxide is a cathodic electrochromic material in which a coloration transition, transparent to blue, occurs by electrochemical reduction.
• Electrochromic materials may be incorporated into, for example, windows for residential, commercial, and other uses.
• the color, transmittance, absorbance, and/or reflectance of such windows may be changed by changing a feature of the electrochromic material, that is, electrochromic windows are windows that can be darkened or lightened electronically.
• electrochromic windows are windows that can be darkened or lightened electronically.
• a small voltage applied to an electrochromic device of the window will cause them to darken; reversing the voltage causes them to lighten. This capability allows control of the amount of light that passes through the windows, and presents an opportunity for electrochromic windows to be used as energy-saving devices.
• electrochromism was discovered in the 1960s, electrochromic devices, and particularly electrochromic windows, still unfortunately suffer various problems and have not begun to realized their full commercial potential despite many recent advances in electrochromic technology, apparatus and related methods of making and/or using electrochromic devices.
• the electrochromic device or electrochromic device precursor includes an electrochromic layer that includes an electrochromic material that includes tungsten, molybdenum, and oxygen. This material is generally referred to as tungsten molybdenum oxide.
• the tungsten molybdenum oxide electrochromic material may be paired with a particular counter electrode material, for example to provide desirable color qualities when the device is in a tinted state.
• the tungsten molybdenum oxide electrochromic material may be paired with particular counter electrode materials where an intrinsic ion conducting and electrically insulating layer is formed after the tungsten molybdenum oxide electrochromic material and counter electrode material in question are layered in direct contact with each other.
• the tungsten molybdenum oxide electrochromic material is part of a layered stack of electrochromic materials.
• the layered stack of electrochromic materials may be combined with a layered stack of counter electrode materials, with a conventional ion conductor layer or an intrinsic ion conductor layer formed in situ as described above.
• a layered stack of the electrochromic material, the counter electrode materials, or both may be substituted with a single layer which has a graded composition, that is, the composition of the stack varies across the thickness of the stack.
• an electrochromic device or an electrochromic device precursor including: a first electrically conductive layer having a thickness between about 10-500 nm; an electrochromic layer including an electrochromic material including tungsten molybdenum oxide having a composition according to the formula Wi-JVIO c O y , where x is between about 0.05-0.30 and y is between about 2.5-4.5.
• the electrochromic layer may have a thickness between about 100-500 nm; a counter electrode layer including a counter electrode material including nickel tungsten oxide, the counter electrode layer having a thickness between about 100-500 nm; and a second electrically conductive layer having a thickness between about 100-400 nm, where the electrochromic layer and the counter electrode layer are positioned between the first electrically conductive layer and the second electrically conductive layer, and where the electrochromic device is all solid state and inorganic.
• the electrochromic layer may be crystalline (e.g., nanocrystalline, microcrystalline, or a combination thereof). In some embodiments, the electrochromic layer may be amorphous. Heating the device during fabrication may impart special properties to the electrochromic layer, including durability, faster switching and improved adhesion.
• the counter electrode material may be crystalline (e.g., nanocrystalline, microcrystalline, or a combination thereof). In some embodiments, the counter electrode layer may be amorphous. In certain implementations, the counter electrode material includes nickel tungsten tantalum oxide. In certain implementations, the counter electrode material includes nickel tungsten niobium oxide. In certain implementations, the counter electrode material includes nickel tungsten tin oxide.
• One or more of the layers of the electrochromic device or electrochromic device precursor may be formed through sputtering.
• the electrochromic layer, the counter electrode layer, and the second electrically conductive layer are all formed through sputtering.
• the electrochromic device or electrochromic device precursor does not include a homogenous layer of ion conducting, electronically insulating material between the electrochromic layer and the counter electrode layer.
• the electrochromic material is in physical contact with the counter electrode material.
• at least one of the electrochromic layer and the counter electrode layer may include two or more layers or portions, one of the layers or portions being superstoichiometric with respect to oxygen.
• the electrochromic layer includes the two or more layers, the layer that is superstoichiometric with respect to oxygen being in contact with the counter electrode layer
• the counter electrode layer includes the two or more layers, the layer that is superstoichiometric with respect to oxygen being in contact with the electrochromic layer.
• the electrochromic layer includes the two or more portions, the two or more portions together forming the electrochromic layer as a graded layer, the portion of the electrochromic layer that is superstoichiometric with respect to oxygen being in contact with the counter electrode layer
• the counter electrode layer includes the two or more portions, the two or more portions together forming the counter electrode layer as a graded layer, the portion of the counter electrode layer that is superstoichiometric with respect to oxygen being in contact with the electrochromic layer.
• the electrochromic device or electrochromic device precursor further includes a material that is ion conducting and substantially electronically insulating that is formed in situ at an interface between the electrochromic layer and the counter electrode layer.
• the electrochromic device or electrochromic device precursor further includes an ion conducting layer including a material selected from the group consisting of: lithium silicate, lithium aluminum silicate, lithium oxide, lithium tungstate, lithium aluminum borate, lithium borate, lithium zirconium silicate, lithium niobate, lithium borosilicate, lithium phosphosilicate, lithium nitride, lithium oxynitride, lithium aluminum fluoride, lithium phosphorus oxynitride (LiPON), lithium lanthanum titanate (LLT), lithium tantalum oxide, lithium zirconium oxide, lithium silicon carbon oxynitride (LiSiCON), lithium phosphate, lithium titanium phosphate, lithium germanium vanadium oxide, lithium zinc germanium oxide, and combinations thereof.
• an ion conducting layer including a material selected from the group consisting of: lithium silicate, lithium aluminum silicate, lithium oxide, lithium tungstate, lithium aluminum borate, lithium borate, lithium zirconium silicate, lithium niobate
• the ion conducting layer may have a thickness between about 5-100 nm.
• the ion conducting layer includes a material selected from the group consisting of: lithium silicate, lithium aluminum silicate, lithium zirconium silicate, lithium borosilicate, lithium phosphosilicate, lithium phosphorus oxynitride (LiPON), lithium silicon carbon oxynitride (LiSiCON), and combinations thereof.
• a method of fabricating an electrochromic device or an electrochromic device precursor including: receiving a substrate with a first electrically conductive layer thereon; forming an electrochromic layer including an electrochromic material including tungsten molybdenum oxide having a composition according to the formula WiJVlO c O y , where x is between about 0.05-0.20 and y is between about 2.5-4.5; forming a counter electrode layer including a counter electrode material including nickel tungsten oxide; and forming a second electrically conductive layer, where the electrochromic layer and the counter electrode layer are positioned between the first electrically conductive layer and the second electrically conductive layer, and where the electrochromic device is all solid state and inorganic.
• the electrochromic layer may be crystalline (e.g., nanocrystalline, microcrystalline, or a combination thereof). In some embodiments, the electrochromic layer may be amorphous. In these or other embodiments, the counter electrode layer may be crystalline (e.g., nanocrystalline, microcrystalline, or a combination thereof). In some embodiments, the counter electrode layer is amorphous. In certain implementations, the counter electrode material includes nickel tungsten tantalum oxide. In certain implementations, the counter electrode material includes nickel tungsten niobium oxide. In some implementations, the counter electrode material includes nickel tungsten tin oxide.
• One or more of the layers may be formed through sputtering.
• the electrochromic layer, the counter electrode layer, and the second electrically conductive layer are all formed through sputtering.
• the electrochromic device or electrochromic device precursor does not include a homogeneous layer of ion conducting, electronically insulating material between the electrochromic layer and the counter electrode layer.
• the electrochromic material may be in physical contact with the counter electrode material.
• at least one of the electrochromic layer and the counter electrode layer may include two or more layers or portions, one of the layers or portions being superstoichiometric with respect to oxygen.
• the electrochromic layer includes the two or more layers, the layer that is superstoichiometric with respect to oxygen being in contact with the counter electrode layer, or (b) the counter electrode layer includes the two or more layers, the layer that is superstoichiometric with respect to oxygen being in contact with the electrochromic layer.
• the electrochromic layer includes the two or more portions, the portion of the electrochromic layer that is superstoichiometric with respect to oxygen being in contact with the counter electrode layer, or (b) the counter electrode layer includes the two or more portions, the portion of the counter electrode layer that is superstoichiometric with respect to oxygen being in contact with the electrochromic layer.
• the method may further include forming in situ an ion conducting layer including a material that is ionically conductive and substantially electronically insulating, the ion conducting layer being positioned at an interface between the electrochromic layer and the counter electrode layer.
• the method may further include forming an ion conducting layer including a material selected from the group consisting of: lithium silicate, lithium aluminum silicate, lithium oxide, lithium tungstate, lithium aluminum borate, lithium borate, lithium zirconium silicate, lithium niobate, lithium borosilicate, lithium phosphosilicate, lithium nitride, lithium oxynitride, lithium aluminum fluoride, lithium phosphorus oxynitride (LiPON), lithium lanthanum titanate (LLT), lithium tantalum oxide, lithium zirconium oxide, lithium silicon carbon oxynitride (LiSiCON), lithium phosphate, lithium titanium phosphate, lithium germanium vanadium oxide, lithium zinc germanium oxide, and combinations thereof, wherein the ion conducting layer is formed before forming at least one of the electrochromic layer and counter electrode layer.
• the ion conducting layer may have a thickness between about 5-100 nm.
• the ion conducting layer may include a material selected from the group consisting of: lithium silicate, lithium aluminum silicate, lithium zirconium silicate, lithium borosilicate, lithium phosphosilicate, lithium phosphorus oxynitride (LiPON), lithium silicon carbon oxynitride (LiSiCON), and combinations thereof.
• the electrochromic layer may be formed by sputtering using one or more metal-containing targets and a first sputter gas including between about 40-80% O2 and between about 20-60% Ar, where the substrate is heated, at least intermittently, to between about 150-450°C during formation of the electrochromic layer, the electrochromic layer having a thickness between about 200-700 nm, and the counter electrode layer is formed by sputtering using one or more metal-containing targets and a second sputter gas including between about 30-100% O2 and between about 0-30% Ar, the counter electrode layer having a thickness between about 100-400 nm.
• the method may include, after forming the counter electrode layer: heating the substrate in an inert atmosphere at a temperature between about 150-450°C for a duration between about 10-30 minutes; after heating the substrate in the inert atmosphere, heating the substrate in an oxygen atmosphere at a temperature between about 150-450°C for a duration between about 1-15 minutes; and after heating the substrate in the oxygen atmosphere, heating the substrate in air at a temperature between about 250-350°C for a duration between about 20-40 minutes.
• the substrate may be maintained in a vertical orientation during formation of the electrochromic layer, the counter electrode layer, and the second electrically conductive layer.
• Figure 1 depicts a view of an electrochromic device according to certain implementations .
• Figure 2A is a flowchart of a process flow describing aspects of a method of fabricating an electrochromic device, according to embodiments.
• Figure 2B are top views depicting steps in the process flow described in relation to Figure 2A.
• Figure 2C depicts cross-sections of the electrochromic lite described in relation to Figure 2B.
• Figure 2D is a flowchart that describes a method of depositing an electrochromic stack on a substrate.
• Figure 3A depicts an integrated deposition system according to certain embodiments.
• Figure 3B depicts an integrated deposition system in a perspective view.
• Figure 3C depicts a modular integrated deposition system.
• Figure 3D depicts an integrated deposition system with two lithium deposition stations.
• Figure 3E depicts an integrated deposition system with one lithium deposition station.
• Figure 4 depicts an example of an electrochromic stack having a cathodic electrochromic layer that includes two sublayers
• Figure 5 depicts an additional example of an electrochromic stack having anodic electrochromic layer that includes multiple sublayers.
• the electrochromic device includes an electrochromic material having a particular composition including at least tungsten, molybdenum, and oxygen. The amount of oxygen in the material will vary according to the stoichiometry of the metals in the composition, but may be defined more specifically as described below.
• FIG. 1 A schematic cross-section of an electrochromic device 100 in accordance with some embodiments is shown in Figure 1.
• the electrochromic device includes a substrate 102, a conductive layer (CL) 104, an electrochromic layer (EC) 106, an ion conducting layer (IC) 108, a counter electrode layer (CE) 110, and a conductive layer (CL) 114.
• Elements 104, 106, 108, 110, and 114 are collectively referred to as an electrochromic stack 120.
• the ion conductor layer 108 may be omitted, as discussed further below.
• a voltage source 116 operable to apply an electric potential across the electrochromic stack 120 effects the transition of the electrochromic device from, e.g., a bleached state to a colored state.
• the order of layers is reversed with respect to the substrate. That is, the layers are in the following order: substrate, conductive layer, counter electrode layer, ion conducting layer, electrochromic material layer, conductive layer.
• Electrochromic layer 106 is cathodically coloring, while the counter electrode layer 110 may be anodically coloring or optically passive (sometimes referred to as an“ion storage layer” because ions reside there when the device is not tinted).
• an“ion storage layer” because ions reside there when the device is not tinted.
• tungsten oxide cathodically colors to an intense blue shade nickel oxide anodically colors to a brown hue. When colored in tandem, a more neutral blue color is created. Still, improvements are needed. The inventors have discovered that certain material changes to tungsten oxide cathodic materials, when colored in tandem with certain nickel oxide based anodic materials, make for a more aesthetically pleasing hue for electrochromic windows.
• the reference to a transition between a bleached state and colored state is non-limiting and suggests only one example, among many, of an electrochromic transition that may be implemented. Unless otherwise specified herein, whenever reference is made to a bleached-colored transition, the corresponding device or process encompasses other optical state transitions such non-reflective-reflective, transparent-opaque, etc. Further the term“bleached” refers to an optically neutral state, e.g., uncolored, transparent or translucent. Still further, unless specified otherwise herein, the“color” of an electrochromic transition is not limited to any particular wavelength or range of wavelengths. As understood by those of skill in the art, the choice of appropriate electrochromic and counter electrode materials governs the relevant optical transition.
• the electrochromic device reversibly cycles between a bleached state and a colored state.
• a potential is applied to the electrochromic stack 120 such that available ions in the stack that can cause the electrochromic material 106 to be in the colored state reside primarily in the counter electrode 110.
• the potential on the electrochromic stack is reversed, the ions are transported across the ion conducting layer 108 to the electrochromic material 106 and cause the material to enter the colored state.
• all of the materials making up electrochromic stack 120 are inorganic, solid (i.e., in the solid state), or both inorganic and solid.
• inorganic materials offer the advantage of a reliable electrochromic stack that can function for extended periods of time.
• Materials in the solid state also offer the advantage of not having containment and leakage issues, as materials in the liquid state often do.
• Each of the layers in the electrochromic device is discussed in detail, below. It should be understood that any one or more of the layers in the stack may contain some amount of organic material, but in many implementations one or more of the layers contains little or no organic matter. The same can be said for liquids that may be present in one or more layers in small amounts.
• solid state material may be deposited or otherwise formed by processes employing liquid components such as certain processes employing sol-gels or chemical vapor deposition.
• voltage source 116 is typically a low voltage electrical source (on the order of between about IV and about 20V, depending upon the electrochromic device used) and may be configured to operate in conjunction with radiant and other environmental sensors. Voltage source 116 may also be configured to interface with an energy management system, such as a computer system that controls the electrochromic device according to factors such as the time of year, time of day, and measured environmental conditions. Such an energy management system, in conjunction with large area electrochromic devices (i.e., an electrochromic window), can dramatically lower the energy consumption of a building.
• an energy management system in conjunction with large area electrochromic devices (i.e., an electrochromic window) can dramatically lower the energy consumption of a building.
• any material having suitable optical, electrical, thermal, and mechanical properties may be used as substrate 102 in Figure 1.
• substrates include, for example, glass, plastic, and mirror materials.
• the substrate includes a glass such as a soda lime glass.
• a substrate may include one or more optional optical tuning and/or ion diffusion barrier layers. Examples of these include silica, titanium dioxide, and undoped tin oxide.
• Each of an optical tuning and/or ion diffusion barrier layer may have a thickness of about 1 - 100 nm. In one embodiment, an optical tuning and/or an ion diffusion barrier layer may have a thickness of about 5 - 50 nm, or 5 - 30 nm
• One or more such layers may be employed.
• such layers include at least a silica layer and an undoped tin oxide layer.
• such layers include at least two separated silica layers. Further examples of such layers are provided in US Patent No. 5,168,003, which is incorporated herein by reference in its entirety.
• the substrate may be of any thickness, as long as it has suitable mechanical properties to support the electrochromic stack 120. While the substrate 102 may be of any thickness or transparent material, in some embodiments, it is glass or plastic and is between about 0.01 mm and about 10 mm thick. In certain embodiments the substrate is glass that is between about 3 mm to 9 mm thick, and may be tempered.
• the glass may be very thin, between about 0.01 mm and 1 mm thick, or between about 0.1 mm and 1 mm thick, and be sodium-free or have very low sodium or other alkali content, e.g., substrates such as Coming, Incorporated’s (of Corning, New York) Gorilla®, Willow®, EagleXG®, or other similar glass substrates from commercial sources, such as those from Asahi Glass Corporation (AGC, of Tokyo, Japan).
• substrates such as Coming, Incorporated’s (of Corning, New York) Gorilla®, Willow®, EagleXG®, or other similar glass substrates from commercial sources, such as those from Asahi Glass Corporation (AGC, of Tokyo, Japan).
• the substrate is architectural glass.
• Architectural glass is glass that is used as a building material.
• Architectural glass is typically used in commercial buildings, but may also be used in residential buildings, and typically, though not necessarily, separates an indoor environment from an outdoor environment.
• architectural glass is at least 20 inches by 20 inches, and can be much larger, e.g., as large as about 72 inches by 120 inches.
• Architectural glass is typically at least about 2 mm thick.
• conductive layer 104 on top of substrate 102 is conductive layer 104.
• one or both of the conductive layers 104 and 114 is inorganic and/or solid state.
• Conductive layers 104 and 114 may be made from a number of different materials, including conductive oxides, thin metallic coatings, conductive metal nitrides, and composite conductors of metal oxides and metals.
• the first conductive layer, closest to the substrate is a metallic layer while the second conducting layer is a transparent metal oxide.
• Such constructs are useful for electrochromic mirrors, where incoming light is reflected off the first conductive layer and must pass through the electrochromic materials, and thus a dimming mirror is achieved.
• Transparent conductive oxides include metal oxides and metal oxides doped with one or more metals.
• metal oxides and doped metal oxides include indium oxide, indium tin oxide, doped indium oxide, tin oxide, doped tin oxide, fluorinated tin oxide, zinc oxide, aluminum zinc oxide, doped zinc oxide, ruthenium oxide, doped ruthenium oxide and the like. Since oxides are often used for these layers, they are sometimes referred to as“transparent conductive oxide” (TCO) layers.
• TCO transparent conductive oxide
• Thin metallic coatings that are substantially transparent may also be used.
• metals used for such thin metallic coatings include transition metals including gold, platinum, silver, aluminum, nickel alloy, and the like.
• Thin metallic coatings based on silver, well known in the glazing industry are also used.
• Examples of conductive nitrides include titanium nitrides, tantalum nitrides, titanium oxynitrides, and tantalum oxynitrides.
• the conductive layers 104 and 114 may also be composite conductors. Such composite conductors may be fabricated by placing highly conductive ceramic and metal wires or conductive layer patterns on one of the faces of the substrate and then over-coating with transparent conductive materials such as doped tin oxides or indium tin oxide.
• Such wires should be thin enough as to be invisible to the naked eye (e.g., about IOOmhi or thinner).
• Other composite conductors include metal oxide-metal-metal oxide sandwiched materials, such as indium tin oxide-metal-indium tin oxide layers, sometimes generically referred to as“IMI’s,” where the metal is e.g., silver, gold, copper, aluminum or alloys thereof.
• commercially available substrates such as glass substrates contain a transparent conductive layer coating.
• Such products may be used for both substrate 102 and conductive layer 104.
• Examples of such glasses include conductive layer coated glasses sold under the trademark TEC GlassTM by Pilkington, of Toledo, Ohio and SUNGATETM 300 and SUNGATETM 500 by PPG Industries of Pittsburgh, Pennsylvania.
• TEC GlassTM is a glass coated with a fluorinated tin oxide conductive layer.
• the same conductive layer is used for both conductive layers (i.e., conductive layers 104 and 114).
• different conductive materials are used for each conductive layer 104 and 114.
• TEC GlassTM is used for substrate 102 (float glass) and conductive layer 104 (fluorinated tin oxide) and indium tin oxide is used for conductive layer 114.
• TEC GlassTM there is a sodium diffusion barrier between the glass substrate 102 and TEC conductive layer 104.
• conductive layer 104 has a layer of titanium dioxide on it, opposite the side abutting the substrate.
• the layer of titanium dioxide has a thickness of about 50 nm or less.
• the optional titanium dioxide layer may be employed for its optical and/or insulating properties. Examples of stacks employing titanium dioxide layers are provided in US Patent Application Publication No. 2014/0022621, published January 23, 2014, which is incorporated herein by reference in its entirety.
• the function of the conductive layers is to spread an electric potential provided by voltage source 116 over surfaces of the electrochromic stack 120 to interior regions of the stack, with very little ohmic potential drop.
• the electric potential is transferred to the conductive layers though electrical connections to the conductive layers.
• bus bars one in contact with conductive layer 104 and one in contact with conductive layer 114, provide the electric connection between the voltage source 116 and the conductive layers 104 and 114.
• the conductive layers 104 and 114 may also be connected to the voltage source 116 with other conventional means.
• the two conductive layers may be resistance matched, even in cases where they are composed of different materials. Resistance matching avoids cases where one conductive layer becomes a tinting bottleneck, as the conductive layer with higher resistance limits tinting time. Also, in such instances uneven tinting fronts can be an issue.
• the thickness of conductive layers 104 and 114 is between about 5 nm and about 10,000 nm. In some embodiments, the thickness of conductive layers 104 and 114 are between about 10 nm and about 1,000 nm. In other embodiments, the thickness of conductive layers 104 and 114 are between about 10 nm and about 500 nm. In some embodiments where TEC GlassTM is used for substrate 102 and conductive layer 104, the conductive layer is about 300 to 400 nm thick. In some embodiments where indium tin oxide is used for conductive layer 114, the conductive layer is about 100 nm to 500 nm thick (280 nm in one embodiment).
• the conductive layers 104 and 114 are as thin as possible to increase transparency and to reduce cost.
• one or both conductive layers are crystalline or substantially crystalline.
• conductive layers are crystalline with a high fraction of large equiaxed grains.
• the sheet resistance (R s ) of the conductive layers is also important because of the relatively large area spanned by the layers in large electrochromic windows.
• the sheet resistance of conductive layers 104 and 114 is about 5 to 30 Ohms per square. In some embodiments, the sheet resistance of conductive layers 104 and 114 is about 15 Ohms per square. In general, it is desirable that the sheet resistance of each of the two conductive layers be about the same. In one embodiment, the two layers each have a sheet resistance of about 10-15 Ohms per square. In one embodiment, the two layers each have a sheet resistance of less than 10 Ohms per square or less than 5 Ohms per square or less than 3 Ohms per square.
• electrochromic layer 106 overlaying conductive layer 104 is electrochromic layer 106.
• electrochromic layer 106 is inorganic and/or solid, in typical embodiments inorganic and solid.
• a number of different materials can be used for the electrochromic layer 106.
• the electrochromic layer may contain e.g., tungsten oxide. The inventors have found that electrochromic devices that use tungsten molybdenum oxides in the electrochromic layer, as described herein, possess improved properties over conventional devices.
• Electrochromic metal oxides may further include protons, lithium, sodium, potassium, or other ions.
• An electrochromic layer 106 as described herein is capable of receiving such ions transferred from counter electrode layer 110.
• Tungsten oxide has long been used as an electrochromic material. Over time, various materials have been added to tungsten oxide to adjust its properties.
• the electrochromic layer 106 includes an electrochromic material that includes tungsten, molybdenum, and oxygen. This material may be referred to as tungsten molybdenum oxide.
• Tungsten molybdenum oxide exhibits both a high degree of durability and improved color properties over conventional devices, particularly when used in combination with certain nickel oxide based counter electrode materials, such as nickel oxide that contains one or more of tungsten oxide, tantalum oxide, niobium oxide, tin oxide and mixtures thereof.
• molybdenum in the electrochromic material changes the color properties of the electrochromic layer, resulting in an electrochromic device that is more color neutral.
• Tungsten oxide for example, has an intense blue appearance that can be undesirable. This blue color is made more neutral with the inclusion of molybdenum.
• the tungsten molybdenum oxide materials used in electrochromic devices described herein may be represented by the formula: Wi- Mo O , where the total amount of tungsten and molybdenum in the material is represented in relative atomic percentage where x is the atomic percentage of molybdenum and l-x represents the atomic percentage of tungsten.
• a compound represented by W0 . 90M00 . 10O3 has a metal content that is 90% (atomic) tungsten, and 10% (atomic) of molybdenum.
• the actual material contains oxygen as well as the two metals.
• y represents the stoichiometry of the oxygen in the compound relative to, collectively, the metals. In certain embodiments, y is between about 2.5 and about 4.5. In one embodiment, y is between about 3.0 and about 3.5. In one embodiment, y is between about 3.0 and about 3.2.
• the value of y can have a strong effect on the properties of the material. Such properties may include whether or not the material exhibits electrochromism and whether or not the material can function as a precursor to an ion conducting material.
• electrochromic tungsten oxide represented by WO v
• electrochromic tungsten oxide may have an oxygen content where y is 3 or less, typically between about 2.5 and 3, and superstoichiometric tungsten oxide (which is superstoichiometric with respect to oxygen and may act as a precursor to an ion conducting material), represented by WO v , has an oxygen content where y is greater than 3, for example between 3.1 and 4.5; the tungsten and molybdenum in the compounds described herein, collectively, may have the same associated amounts of oxygen.
• the material may have 3 or less oxygen atoms per metal atom for tungsten molybdenum oxide that exhibits electrochromism, or more than 3 oxygen atoms per metal atom for tungsten molybdenum oxide that is superstoichiometric with respect to oxygen (and which may act as a precursor to an ion conducting material).
• y is 3 or less, representing a stoichiometric or substoichiometric oxygen level for the combined two metals in the material, the material is cathodically coloring.
• the electrochromic tungsten molybdenum oxide is more color neutral than e.g., electrochromic tungsten oxide, which has an intense and deep blue color when tinted (e.g., via insertion of positive ions such as protons or lithium ions, and electrons).
• the material when y is 3 or greater, is superstoichiometrically oxygenated, e.g., when used in methods of manufacture to fabricate electrochromic devices (and may be stable as such in an electrochromic device precursor used in the aforementioned methods of manufacture) as described in more detail herein.
• x may be at least about 0.05, or at least about 0.10, or at least about 0.15. In these or other cases, x may be about 0.30 or less, or about 0.25 or less, or about 0.2 or less. In some implementations, x is about 0.05 and 0.30, or between about 0.10 and 0.25, or between about 0.15 and 0.2. In these or other implementations, y may be between about 2.5-4.5, or between about 2.5- 3.0, or between about 2.5-2.9, or between about 3.0-3.5, or between about 3.5-4.5.
• y may be at least about 2.5, for example at least about 2.7, or at least about 2.9, or at least about 3.0, or at least about 3.5, or at least about 4.0. In these or other cases, y may be about 4.5 or less, for example about 4.0 or less, or about 3.5 or less, or about 3.3 or less, or about 3.1 or less, or about 3.0 or less, or about 2.9 or less. In certain embodiments, y is about 2.5 to 3.5, about 2.7 to 3.3, about 2.8 to 3.2, or about 2.8 to 3.1.
• the electrochromic material may further include titanium.
• the electrochromic material may include tungsten, titanium, molybdenum and oxygen. This material may be referred to as tungsten titanium molybdenum oxide.
• the inclusion of titanium in the electrochromic material may increase the stability/durability of the electrochromic layer, meaning that the resulting electrochromic device is less likely to break down over time with repeated insertion/extraction of ions and electrons.
• the electrochromic layer may include two or more materials (e.g., deposited as a bilayer, graded layer, or other combination of layers) having different compositions, one or both of which may include tungsten molybdenum oxide.
• the electrochromic layer includes two or more materials, one of the materials may provide electrochromic properties, and the other material may act as a precursor for a material that is ion conducting and substantially electronically insulating.
• a tungsten oxide portion of an electrochromic stack is deposited in at least two different compositions having different amounts of oxygen.
• the tungsten molybdenum electrochromic layer is deposited as a bilayer where in a first layer of the bilayer, y is between about 2.5 and about 3.5, and in a second layer of the bilayer, y is greater than 3.
• the tungsten molybdenum electrochromic layer is deposited as a single graded layer fabricated such that the value of y varies as a function of the depth of the layer. For example, tungsten molybdenum oxide is sputtered onto a substrate at a first oxygen gas concentration in an initial portion of the deposition, then the oxygen gas concentration is increased as additional tungsten molybdenum oxide material is deposited.
• Such varying oxygen concentration between multiple layers or in a graded layer can be used to fabricate ion conductor material in situ, e.g. after a counter electrode material is deposited and at the interface between the tungsten molybdenum material and the counter electrode material, as is described in more detail below.
• This fabrication scheme assumes that the electrochromic layer is formed prior to the counter electrode layer.
• the first and second layers of the electrochromic layer may be swapped (e.g., such that the electrochromic material that acts as a precursor for the material that is ion conducting and substantially electronically insulating is deposited prior to the electrochromic material that exhibits electrochromism).
• the electrochromic layer is deposited in at least two different compositions that have different metals or combinations of metals therein.
• the electrochromic layer is deposited as a bilayer, where a first layer of the bilayer includes at least one metal that is not present in the second layer of the bilayer.
• the second layer of the bilayer may include at least one metal that is not present in the first layer of the bilayer.
• the first layer of the bilayer is tungsten molybdenum oxide (e.g., Wi-JVlO c O y , where y is about 3.5 or less), and the second layer of the bilayer is tungsten oxide (e.g., WO y , where y is greater than 3).
• tungsten molybdenum oxide e.g., Wi-JVlO c O y , where y is about 3.5 or less
• the second layer of the bilayer is tungsten oxide (e.g., WO y , where y is greater than 3).
• the first layer of the bilayer is tungsten molybdenum oxide (e.g., Wi- ⁇ Mo ⁇ O v , where y is about 3.5 or less), and the second layer of the bilayer is tungsten molybdenum oxide (e.g., Wi- ⁇ Mo ⁇ O v , where x is between about 0.05 and 0.20, or between about 0.05 and 0.08; and y is greater than 3).
• tungsten molybdenum oxide e.g., Wi- ⁇ Mo ⁇ O v , where x is between about 0.05 and 0.20, or between about 0.05 and 0.08; and y is greater than 3
• the first and second layers of the bilayer may be switched, e.g., such that the second layer of the bilayer is Wi, ⁇ Mo ⁇ O v (where y is greater than 3), and the first layer of the bilayer is WO v or Wi, ⁇ Mo ⁇ O v (where x is as described above with respect to Wi-JVlO c O y , and where y is about 3.5 or less).
• the values of x and y may be within the ranges described elsewhere herein.
• each layer of the bilayer may have a distinct morphology.
• each of the first and second layers of the bilayer has a morphology comprising a microcrystalline phase, a nanocrystalline phase, or an amorphous phase, where each of the first and second layers’ morphology is distinct.
• the first layer of the bilayer is tungsten molybdenum oxide (e.g., Wi- ⁇ Mo ⁇ O v , where y is about 3.5 or less) that is amorphous
• the second layer of the bilayer is tungsten oxide (e.g., WO,, where y is greater than 3) that is nanocrystalline.
• the first layer of the bilayer is crystalline tungsten molybdenum oxide (e.g., Wi- ⁇ Mo ⁇ O v , where y is about 3.5 or less), and the second layer of the bilayer is amorphous tungsten oxide (e.g., WO,, where y is greater than 3).
• crystalline tungsten molybdenum oxide e.g., Wi- ⁇ Mo ⁇ O v , where y is about 3.5 or less
• the second layer of the bilayer is amorphous tungsten oxide (e.g., WO,, where y is greater than 3).
• Different morphologies for the layers may be chosen for specific purposes or result from the specific process conditions and/or materials used for each layer.
• the counter electrode layer may similarly be deposited as a bilayer or graded layer that includes two or more materials that may have different compositions with respect to oxygen content, metal content, etc.
• the tungsten molybdenum oxide may have a molybdenum content of at least about 5 % (atomic), at least about 6 % (atomic), at least about 8 % (atomic), or at least about 9 % (atomic), or at least about 10 % (atomic), or at least about 12 % (atomic), or at least about 15 % (atomic).
• the tungsten molybdenum oxide may have a molybdenum content of about 30 % (atomic) or less, for example about 25 % (atomic) or less, or about 20 % (atomic) or less, or about 18 % (atomic) or less.
• the tungsten molybdenum oxide is between about 5-30 % (atomic), or about 10-25 % (atomic), or about 15-20 % (atomic), molybdenum.
• the tungsten molybdenum oxide electrochromic material is crystalline, nanocrystalline, or amorphous.
• the electrochromic material is substantially nanocrystalline, with grain sizes, on average, from about 5 nm to 50 nm (or from about 5 nm to 20 nm), as characterized by transmission electron microscopy (TEM).
• the electrochromic material morphology may also be characterized as nanocrystalline using x-ray diffraction (XRD); XRD.
• nanocrystalline electrochromic material may be characterized by the following XRD features: a crystal size of about 10 to 100 nm (e.g., about 55nm.
• nanocrystalline electrochromic material may exhibit limited long range order, e.g., on the order of several (about 5 to 20) electrochromic material unit cells.
• the tungsten molybdenum oxide electrochromic material may be amorphous. A number of factors may affect the morphology of the electrochromic material, including, for example, the composition of the material and the conditions used to deposit and treat the material.
• the electrochromic material is not subjected to heating above a particular temperature (e.g., any processing involving heating the substrate during or after deposition of the electrochromic material may be kept below about 300 °C, below about 250°C, below about 200°C, below about 150°C, below about 100°C, below about 75°C, or below about 50°C). Without wishing to be bound by theory or mechanism of action, this lack of heating may contribute to an amorphous morphology for the tungsten molybdenum oxide. In some other embodiments, heating the substrate may cause the tungsten molybdenum oxide’s morphology to become crystalline/nanocrystalline.
• the content in the tungsten molybdenum oxide inhibits crystallization, but under the processing conditions described herein, e.g., higher temperatures and combination of heating under inert atmosphere followed by heating in air, a more crystalline morphology can be formed.
• the different materials may each independently include microcrystalline, nanocrystalline, and/or amorphous phases.
• a first layer or lower portion of the electrochromic layer is microcrystalline or nanocrystalline and a second layer or upper portion of the electrochromic layer is amorphous.
• the first layer or lower portion of the electrochromic layer is amorphous and a second layer or upper portion of the electrochromic layer is microcrystalline or nanocrystalline.
• both the first layer/lower portion and the second layer/upper portion of the electrochromic layer are microcrystalline or nanocrystalline.
• both the first layer/lower portion and the second layer/upper portion of the electrochromic layer are amorphous.
• the thickness of the electrochromic layer 106 depends on the electrochromic material selected for the electrochromic layer. In some embodiments, the electrochromic layer 106 is about 50 nm to 2,000 nm, or about 200 nm to 700 nm. In some embodiments, the electrochromic layer is about 300 nm to about 500 nm. In certain embodiments employing an additional tungsten oxide layer (e.g., a layer having WO v , where y is greater than 3), the thickness of this additional layer is about 50 to 100 nm. In certain embodiments, this additional layer is amorphous.
• the colorization (or change in any optical property - e.g., absorbance, reflectance, and transmittance) of the electrochromic material is caused by reversible ion insertion into the material (e.g., intercalation) and a corresponding injection of a charge balancing electron.
• a charge balancing electron typically some fraction of the ion responsible for the optical transition is irreversibly bound up in the electrochromic material.
• suitable ions include lithium ions (Li + ) and hydrogen ions (H + ) (i.e., protons).
• lithium ions are used to produce the electrochromic phenomena.
• ion conducting layer 108 overlays electrochromic layer 106.
• counter electrode layer 110 is inorganic and/or solid.
• the counter electrode layer may comprise one or more of a number of different materials that are capable of serving as reservoirs of ions when the electrochromic device is in the bleached state.
• the counter electrode layer transfers some or all of the ions it holds to the electrochromic layer, changing the electrochromic layer to the colored state.
• suitable materials for the counter electrode include nickel oxide (NiO), nickel tungsten oxide (NiWO), nickel tungsten tantalum oxide (NiWTaO), nickel vanadium oxide, nickel chromium oxide, nickel aluminum oxide, nickel manganese oxide, nickel magnesium oxide, chromium oxide ((3 ⁇ 4(3 ⁇ 4), manganese oxide (MnCk), Prussian blue, cerium titanium oxide (CeCk-TiCk), cerium zirconium oxide (CeCk-ZrCk), vanadium oxide (V2O5), and mixtures of oxides (e.g., a mixture of N12O3 and WO3).
• Doped formulations of the oxides may also be used, with dopants including, e.g., tantalum and tungsten.
• dopants including, e.g., tantalum and tungsten.
• Particular examples of counter electrode materials include nickel tungsten tantalum oxide, nickel tungsten niobium oxide, and nickel tungsten tin oxide. Because counter electrode layer 110 contains the ions used to produce the electrochromic phenomenon in the electrochromic material when the electrochromic material is in the bleached state, the counter electrode preferably has high transmittance and a neutral color when it holds significant quantities of these ions.
• a nickel-tungsten oxide is used as a counter electrode material in the counter electrode layer.
• the amount of nickel present in the nickel-tungsten oxide can be up to about 90% by weight of the nickel- tungsten oxide.
• the mass ratio of nickel to tungsten in the nickel- tungsten oxide is between about 4:6 and 6:4 (e.g., about 1:1).
• the NiWO contains about 15% (atomic) Ni to about 60% (atomic) Ni; about 10% (atomic) W to about 40% W (atomic); and about 30% (atomic) O to about 75% (atomic) O.
• the NiWO contains about 30% (atomic) Ni and about 45% (atomic) Ni; about 10% (atomic) W to about 25% (atomic) W; and about 35% (atomic) O to about 50% (atomic) O. In one embodiment, the NiWO contains about 42% (atomic) Ni, about 14% (atomic) W, and about 44% (atomic) O.
• nickel tungsten tantalum oxide (NiWTaO) is used as or in a counter electrode material in the counter electrode layer.
• the nickel tungsten tantalum oxide may have various compositions when used as or in a counter electrode material.
• particular balances may be made between the various components of the NiWTaO. For instance, an atomic ratio of Ni:(W+Ta) in the material may fall between about 1.5:1 and 3: 1, for example between about 1.5: 1 and 2.5:1, or between about 2:1 and 2.5:1. In a particular example the atomic ratio of Ni: (W+Ta) is between about 2: 1 and 3:1.
• the atomic ratio of Ni:(W+Ta) relates to the ratio of (i) nickel atoms in the material to (ii) the sum of the number of tungsten and tantalum atoms in the material.
• the nickel tungsten tantalum oxide material may also have a particular atomic ratio of W:Ta.
• the atomic ratio of W:Ta is between about 0.1: 1 and 6: 1, for example between about 0.2: 1 and 5: 1, or between about 1:1 and 3:1, or between about 1.5: 1 and 2.5:1, or between about 1.5:1 and 2:1.
• the atomic ratio of W:Ta is between about 0.2:1 and 1 : 1 , or between about 1 : 1 and 2: 1 , or between about 2: 1 and 3 : 1 , or between about 3:1 and 4:1, or between about 4:1 and 5: 1.
• particular atomic ratios of Ni:(W+Ta) and W:Ta are used. All combinations of disclosed Ni:(W+Ta) compositions and disclosed W:Ta compositions are contemplated, though only certain combinations are explicitly listed herein.
• the atomic ratio of Ni:(W+Ta) may be between about 1.5:1 and 3:1, where the atomic ratio of W:Ta is between about 1.5:1 and 3:1.
• the atomic ratio of Ni:(W+Ta) may be between about 1.5: 1 and 2.5:1, where the atomic ratio of W:Ta is between about 1.5:1 and 2.5: 1. In a further example, the atomic ratio of Ni:(W+Ta) may be between about 2:1 and 2.5:1, where the atomic ratio of W:Ta is between about 1.5:1 and 2:1, or between about 0.2:1 and 1: 1, or between about 1:1 and 2:1, or between about 4:1 and 5:1.
• NiWNbO nickel tungsten niobium oxide
• the nickel tungsten niobium oxide may have various compositions when used as an anodically coloring material.
• particular balances may be made between the various components of the NiWNbO. For instance, an atomic ratio of Ni:(W+Nb) in the material may fall between about 1.5:1 and 3: 1, for example between about 1.5: 1 and 2.5:1, or between about 2:1 and 2.5:1. In a particular example the atomic ratio of Ni:(W+Nb) is between about 2: 1 and 3:1.
• the atomic ratio of Ni:(W+Nb) relates to the ratio of (i) nickel atoms in the material to (ii) the sum of the number of tungsten and niobium atoms in the material.
• the nickel tungsten niobium oxide material may also have a particular atomic ratio of W:Nb.
• the atomic ratio of W:Nb is between about 0.1:1 and 6:1, for example between about 0.2: 1 and 5: 1, or between about 1:1 and 3:1, or between about 1.5: 1 and 2.5:1, or between about 1.5: 1 and 2:1.
• the atomic ratio of W:Nb is between about 0.2:1 and 1 : 1 , or between about 1 : 1 and 2: 1 , or between about 2: 1 and 3 : 1 , or between about 3:1 and 4:1, or between about 4:1 and 5: 1.
• particular atomic ratios of Ni:(W+Nb) and W:Nb are used. All combinations of disclosed Ni:(W+Nb) compositions and disclosed W:Nb compositions are contemplated, though only certain combinations are explicitly listed herein.
• the atomic ratio of Ni:(W+Nb) may be between about 1.5:1 and 3: 1, where the atomic ratio of W:Nb is between about 1.5:1 and 3:1.
• the atomic ratio of Ni:(W+Nb) may be between about 1.5: 1 and 2.5: 1, where the atomic ratio of W:Nb is between about 1.5:1 and 2.5:1. In a further example, the atomic ratio of Ni:(W+Nb) may be between about 2: 1 and 2.5:1, where the atomic ratio of W:Nb is between about 1.5: 1 and 2:1, or between about 0.2:1 and 1:1, or between about 1:1 and 2:1, or between about 4:1 and 5:1.
• NiWSnO nickel tungsten tin oxide
• the nickel tungsten tin oxide may have various compositions when used as an anodically coloring material.
• particular balances may be made between the various components of the NiWSnO.
• an atomic ratio of Ni:(W+Sn) in the material may fall between about 1:1 and 4:1, for example between about 1:1 and 3:1, or between about 1.5:1 and 3:1 , or between about 1.5:1 and 2.5: 1, or between about 2:1 and 2.5: 1.
• the atomic ratio of Ni:(W+Sn) is between about 2:1 and 3:1.
• the atomic ratio of Ni:(W+Sn) relates to the ratio of (i) nickel atoms in the material to (ii) the sum of the number of tungsten and tin atoms in the material.
• the nickel tungsten tin oxide material may also have a particular atomic ratio of W:Sn.
• the atomic ratio of W:Sn is between about 1:9 and 9:1, for example between about 1: 1 and 3: 1, or between about 1.5:1 and 2.5:1, or between about 1.5: 1 and 2:1.
• particular atomic ratios of Ni:(W+Sn) and W:Sn are used.
• the atomic ratio of Ni:(W+Sn) may be between about 1:1 and 3:1, where the atomic ratio of W:Sn is between about 1:1 and 3:1.
• the atomic ratio of Ni:(W+Sn) may be between about 1.5:1 and 2.5: 1, where the atomic ratio of W:Sn is between about 1.5:1 and 2.5: 1.
• the atomic ratio of Ni:(W+Sn) may be between about 2: 1 and 2.5:1, where the atomic ratio of W:Sn is between about 1.5:1 and 2:1.
• the counter electrode layer When charge is removed from a counter electrode 110 made of nickel tungsten oxide (i.e., ions are transported from the counter electrode 110 to the electrochromic layer 106), the counter electrode layer will turn from a transparent state to a brown colored state. Other electrochromic ally active counter electrode materials may exhibit similar or other colors upon ion removal. [0076] As discussed above with respect to the electrochromic layer, the counter electrode layer may be deposited to include two or more materials (e.g., deposited as a bilayer, graded layer, or other combination of layers) having different compositions.
• one of the counter electrode materials may provide electrochromic properties, and the other counter electrode material may act as a precursor for a material that is ion conducting and substantially electronically insulating.
• the other counter electrode material may act as a precursor for a material that is ion conducting and substantially electronically insulating.
• the counter electrode material that acts as a precursor to the ion conducting and substantially electronically insulating material may be deposited as a first layer or lower portion of the counter electrode layer.
• the counter electrode material that exhibits electrochromism may then be provided as the second layer or upper portion of the counter electrode layer.
• the first layer or lower portion of the counter electrode may be formed of the counter electrode material that exhibits electrochromism
• the second layer or upper portion of the counter electrode may be formed of the counter electrode material that acts as a precursor for the material that is ion conducting and substantially electronically insulating.
• the counter electrode is deposited to include two materials that have different oxygen contents.
• the counter electrode layer may include two different forms of nickel oxide, or two different forms of nickel tungsten oxide, or two different forms of nickel tungsten tantalum oxide, or two different forms of nickel tungsten niobium oxide, or two different forms of nickel tungsten tin oxide, etc., where the two different forms of the counter electrode material have different oxygen concentrations.
• One form of the counter electrode material may exhibit electrochromism, and may have relatively less oxygen.
• the other form of the counter electrode material may or may not exhibit electrochromism, may act as a precursor for a material that is ion conducting and substantially electronically insulating, and may have relatively more oxygen.
• the counter electrode material that has relatively more oxygen and acts as a precursor for the ion conducting and substantially electronically insulating material may be superstoichiometric with respect to oxygen. Details provided herein regarding differences in oxygen content between different layers or portions of the electrochromic or counter electrode layers may apply regardless of whether there are other compositional differences (e.g., different metals) between the two layers or portions in question.
• the counter electrode may be deposited to include two or more materials that have different metal compositions, optionally in different layers disposed closer to and farther from the electrochromic layer.
• a first counter electrode material (in a layer closer to the electrochromic layer) may include one or more metal that is not present in the second counter electrode material.
• the second counter electrode material may include one or more metal that is not present in the first counter electrode material.
• Example first counter electrode materials include, but are not limited to, nickel oxide, nickel tungsten oxide, nickel tungsten tantalum oxide, nickel tungsten tin oxide, and nickel tungsten niobium oxide.
• Example second counter electrode materials likewise include, but are not limited to, nickel oxide, nickel tungsten oxide, nickel tungsten tantalum oxide, nickel tungsten tin oxide, and nickel tungsten niobium oxide. A few example combinations are provided, but are not intended to be limiting.
• the first counter electrode material (in a layer closer to the electrochromic layer) is nickel tungsten oxide and the second counter electrode material is nickel oxide.
• the first counter electrode material is nickel tungsten tantalum oxide and the second counter electrode material is nickel tungsten oxide.
• the first counter electrode material is nickel tungsten tin oxide and the second counter electrode material is nickel tungsten oxide.
• the first counter electrode material is nickel tungsten niobium oxide and the second counter electrode material is nickel tungsten oxide.
• the first counter electrode material (in a layer closer to the electrochromic layer) is nickel tungsten oxide, and the second counter electrode materials is nickel tungsten tantalum oxide. Any of these examples can be modified to include different first/second counter electrode materials.
• the counter electrode morphology may be crystalline, amorphous, or some mixture thereof. Crystalline phases may be nanocrystalline.
• the counter electrode material is amorphous or substantially amorphous. Various substantially amorphous counter electrodes have been found to perform better, under some conditions, in comparison to their crystalline counterparts. The amorphous state of the counter electrode oxide material may be obtained through the use of certain processing conditions, described below. While not wishing to be bound to any theory or mechanism, it is believed that certain amorphous counter electrode oxides are produced by relatively low energy atoms in the sputtering process.
• Low energy atoms are obtained, for example, in a sputtering process with lower target powers, higher chamber pressures (i.e., lower vacuum), and/or larger source to substrate distances.
• Amorphous films are also more likely to form where there is a relatively higher fraction/concentration of heavy atoms (e.g., W). Under the described process conditions, films with better stability under UV/heat exposure are produced.
• Substantially amorphous materials may have some crystalline, typically but not necessarily nanocrystalline, material dispersed in the amorphous matrix.
• the different materials may each independently include microcrystalline, nanocrystalline, and/or amorphous phases.
• a first layer or lower portion of the counter electrode layer is microcrystalline or nanocrystalline and a second layer or upper portion of the counter electrode layer is amorphous.
• the first layer or lower portion of the counter electrode layer is amorphous and a second layer or upper portion of the counter electrode layer is microcrystalline or nanocrystalline.
• both the first layer/lower portion and the second layer/upper portion of the counter electrode layer are microcrystalline or nanocrystalline.
• both the first layer/lower portion and the second layer/upper portion of the counter electrode layer are amorphous.
• the counter electrode morphology may include microcrystalline, nanocrystalline and/or amorphous phases.
• the counter electrode may be, e.g., a material with an amorphous matrix having nanocrystals distributed throughout.
• the nanocrystals constitute about 50% or less of the counter electrode material, about 40% or less of the counter electrode material, about 30% or less of the counter electrode material, about 20% or less of the counter electrode material or about 10% or less of the counter electrode material (by weight or by volume depending on the embodiment).
• the nanocrystals have a maximum diameter of less than about 50 nm, in some cases less than about 25 nm, less than about 10 nm, or less than about 5 nm. In some cases, the nanocrystals have a mean diameter of about 50 nm or less, or about 10 nm or less, or about 5 nm or less (e.g., about 1-10 nm).
• nanocrystal size distribution where at least about 50% of the nanocrystals have a diameter within 1 standard deviation of the mean nanocrystal diameter, for example where at least about 75% of the nanocrystals have a diameter within 1 standard deviation of the mean nanocrystal diameter or where at least about 90% of the nanocrystals have a diameter within 1 standard deviation of the mean nanocrystal diameter.
• counter electrodes that include an amorphous matrix may operate more efficiently compared to counter electrodes that are relatively more crystalline.
• an additive may form a host matrix in which domains of a base anodically coloring material may be found.
• the host matrix is substantially amorphous.
• the only crystalline structures in the counter electrode are formed from a base anodically coloring electrochromic material in, e.g., oxide form.
• a base anodically coloring electrochromic material in oxide form is nickel tungsten oxide.
• Additives may contribute to forming an amorphous host matrix that is not substantially crystalline, but which incorporates domains (e.g., nanocrystals in some cases) of the base anodically coloring electrochromic material.
• Example additives include, but are not limited to, tin, tantalum, and niobium.
• the additive and the anodically coloring base material together form a chemical compound with covalent and/or ionic bonding.
• the compound may be crystalline, amorphous, or a combination thereof.
• the anodically coloring base material forms a host matrix in which domains of the additive exist as discrete phases or pockets.
• certain embodiments include an amorphous counter electrode having an amorphous matrix of a first material, with a second material, also amorphous, distributed throughout the first material in pockets, for example, pockets of the diameters described herein for crystalline materials distributed throughout an amorphous matrix.
• the thickness of the counter electrode is about 50 nm about 650 nm. In some embodiments, the thickness of the counter electrode is about 100 nm to about 400 nm, preferably in the range of about 200 nm to 300 nm.
• the amount of ions held in the counter electrode layer during the bleached state (and correspondingly in the electrochromic layer during the colored state) and available to drive the electrochromic transition depends on the composition of the layers as well as the thickness of the layers and the fabrication method. Both the electrochromic layer and the counter electrode layer are capable of supporting available charge (in the form of lithium ions and electrons) in the neighborhood of several tens of millicoulombs per square centimeter of layer surface area.
• the charge capacity of an electrochromic film is the amount of charge that can be loaded and unloaded reversibly per unit area and unit thickness of the film by applying an external voltage or potential.
• the electrochromic layer has a charge capacity of between about 30 and about 150 mC/cm 2 /micron. In another embodiment, the electrochromic layer has a charge capacity of between about 50 and about 100 mC/cm 2 /micron. In one embodiment, the counter electrode layer has a charge capacity of between about 75 and about 200 mC/cm 2 /micron. In another embodiment, the counter electrode layer has a charge capacity of between about 100 and about 150 mC/cm 2 /micron.
• an ion conductor layer 108 is provided between the electrochromic layer 106 and the counter electrode layer 110.
• an ion conductor material is deposited in a conventional sense, e.g., atop the electrochromic layer via e.g., sputtering, evaporation, sol-gel techniques, and the like, followed by deposition of the counter electrode material.
• a conventional ion conductor layer may be omitted.
• the electrochromic layer and the counter electrode layer may be deposited in direct contact with one another, and an ion conducting material formed in situ at the interface between these two layers may serve the purpose of a conventional ion conductor layer.
• Electrochromic device precursors may include the stack of aforementioned layers prior to the in situ formation of the ion conductor material. Each of these embodiments will be discussed in turn. i. Embodiments Utilizing a Separately Deposited Ion Conducting Layer
• Ion conducting layer 108 serves as a medium through which ions are transported (in the manner of an electrolyte) when the electrochromic device transforms between the bleached state and the colored state.
• ion conducting layer 108 is highly conductive to the relevant ions for the electrochromic and the counter electrode layers, but has sufficiently low electron conductivity that negligible electron transfer takes place during normal operation.
• a thin ion conducting layer with high ionic conductivity permits fast ion conduction and hence fast switching for high performance electrochromic devices.
• the ion conducting layer 108 is inorganic and/or solid.
• the ion conductor layer When fabricated from a material and in a manner that produces relatively few defects, the ion conductor layer can be made very thin to produce a high performance device.
• the ion conductor material has an ionic conductivity of between about 10 8 Siemens/cm or ohm ⁇ crn 1 and about 10 9 Siemens/cm or ohnr'cnr 1 and an electronic resistance of about 10 11 ohms-cm.
• lithium ion conductor layer examples include lithium silicate, lithium aluminum silicate, lithium oxide, lithium tungstate, lithium aluminum borate, lithium borate, lithium zirconium silicate, lithium niobate, lithium borosilicate, lithium phosphosilicate, lithium nitride, lithium oxynitride, lithium aluminum fluoride, lithium phosphorus oxynitride (LiPON), lithium lanthanum titanate (LLT), lithium tantalum oxide, lithium zirconium oxide, lithium silicon carbon oxynitride (LiSiCON), lithium titanium phosphate, lithium germanium vanadium oxide, lithium zinc germanium oxide, and other ceramic materials that allow lithium ions to pass through them while having a high electrical resistance (blocking electron movement therethrough). Any material, however, may be used for the ion conducting layer 108 provided it can be fabricated with low defectivity and it allows for the passage of ions between the counter electrode layer 110 to the electrochromic layer 106 while substantially preventing the passage
• the ion conducting layer is crystalline, nanocrystalline, or amorphous. Typically, the ion conducting layer is amorphous. In another embodiment, the ion conducting layer is nanocrystalline. In yet another embodiment, the ion conducting layer is crystalline.
• a silicon-aluminum-oxide (SiAlO) is used for the ion conducting layer 108.
• a silicon/aluminum target used to fabricate the ion conductor layer via sputtering contains between about 6 and about 20 atomic% aluminum. This defines the ratio of silicon to aluminum in the ion conducting layer.
• the silicon-aluminum-oxide ion conducting layer 108 is amorphous.
• the thickness of the ion conducting layer 108 may vary depending on the material. In some embodiments, the ion conducting layer 108 is about 5 nm to 100 nm thick, preferably about 10 nm to 60 nm thick. In some embodiments, the ion conducting layer is about 15 nm to 40 nm thick or about 25 nm to 30 nm thick.
• Ions transported across the ion conducting layer between the electrochromic layer and the counter electrode layer serve to effect a color change in the electrochromic layer (i.e., change the electrochromic device from the bleached state to the colored state).
• ions include lithium ions (Li + ) and hydrogen ions (H + ) (i.e., protons).
• Li + lithium ions
• H + hydrogen ions
• other ions may be employed in certain embodiments.
• Embodiments Omitting a Separately Deposited Ion Conducting Layer
• the ion conducting layer is deposited as a distinct material in a distinct deposition step to provide separation between the electrochromic layer and the counter electrode layer.
• the ion conducting layer may be omitted.
• the electrochromic material of the electrochromic layer may be deposited in direct physical contact with the counter electrode material of the counter electrode layer.
• An interfacial region between the electrochromic layer and the counter electrode layer may form and serve the function of an ion conductor layer (e.g., allowing passage of ions but not electrons between the electrochromic layer and the counter electrode layer), without the need to ever deposit this layer as a distinct material. This simplifies formation of the electrochromic device, since there is no need to provide a separate deposition step for forming the ion conductor layer.
• one or both of the electrochromic layer and counter electrode layer may be deposited to include a portion that is oxygen-rich compared to the remaining portion of the layer.
• the oxygen-rich portion may be superstoichiometric with respect to oxygen.
• the oxygen-rich portion is in contact with the other type of layer.
• an electrochromic stack may include a counter electrode material in contact with an electrochromic material, where the electrochromic material includes an oxygen-rich portion in direct physical contact with the counter electrode material.
• an electrochromic stack includes a counter electrode material in contact with an electrochromic material, where the counter electrode material includes an oxygen- rich portion in direct physical contact with the electrochromic material.
• both the electrochromic material and the counter electrode material each include an oxygen-rich portion, where the oxygen-rich portion of the electrochromic material is in direct physical contact with the oxygen-rich portion of the counter electrode material.
• an electrochromic and/or counter electrode material may include a first layer that is oxygen-rich and a second layer that is not oxygen-rich (or has relatively less oxygen in comparison to the first layer).
• oxygen-rich refers to a material that is superstoichiometric with respect to oxygen. Further, a material that is“oxygen-rich” in comparison to a second material has a higher degree of superstoichiometric oxygen compared to the second material.
• the electrochromic layer includes two layers of tungsten molybdenum oxide, where a second layer of tungsten molybdenum oxide is oxygen-rich in comparison to the first layer of tungsten molybdenum oxide.
• the second layer of tungsten molybdenum oxide may be superstoichiometric with respect to oxygen.
• the second layer of tungsten molybdenum oxide may be in direct physical contact with the counter electrode layer and with the first layer of tungsten molybdenum oxide.
• the counter electrode layer may be homogeneous, or it may also include an oxygen-rich portion, as noted above.
• the oxygen-rich portion of the layers may also be provided in a graded layer.
• the electrochromic and/or counter electrode material may include a gradient in oxygen concentration, the gradient being in a direction normal to the surface of the layers.
• the electrochromic layer is a graded layer of tungsten molybdenum oxide, having a graded oxygen concentration in a direction normal to the surface of the layer. For instance, the highest oxygen concentration in the graded tungsten molybdenum oxide layer may be proximate the counter electrode layer.
• the counter electrode layer may be homogeneous, or it may also include an oxygen-rich portion, as noted above.
• the electrochromic device 100 may include one or more additional layers (not shown in Figure 1) such as one or more passive layers. Passive layers used to improve certain optical properties may be included in electrochromic device 100. Passive layers for providing moisture or scratch resistance may also be included in the electrochromic device 100. For example, the conductive layers may be treated with anti-reflective or protective oxide or nitride layers. Other passive layers may serve to hermetically seal the electrochromic device 100.
• one or more defect mitigating insulating layers may be provided. Such DMILs may be provided between the layers described in Figure 1, or within such layers. In some particular embodiments a DMIL may be provided between sublayers of a counter electrode layer, though DMILs can also be provided at alternative or additional locations. DMILs can help minimize the risk of fabricating defective devices.
• the insulating layer has an electronic resistivity of between about 1 and 5xl0 10 Ohm-cm.
• the insulating layer contains one or more of the following metal oxides: cerium oxide, titanium oxide, aluminum oxide, zinc oxide, tin oxide, silicon aluminum oxide, tungsten oxide, nickel tungsten oxide, tantalum oxide, and oxidized indium tin oxide.
• the insulating layer contains a nitride, carbide, oxynitride, or oxycarbide such as nitride, carbide, oxynitride, or oxycarbide analogs of the listed oxides.
• the insulating layer includes one or more of the following metal nitrides: titanium nitride, aluminum nitride, silicon nitride, and tungsten nitride.
• the insulating layer may also contain a mixture or other combination of oxide and nitride materials (e.g., a silicon oxynitride).
• oxide and nitride materials e.g., a silicon oxynitride.
• DMILs are further described in U.S. Patent No. 9,007,674, which is herein incorporated by reference in its entirety.
• FIG. 4 shows an example of an electrochromic stack having a cathodic electrochromic layer that includes two sublayers.
• the stack in Figure 4 includes transparent conductive oxide layers 404 and 414, cathodically coloring electrochromic layer 406, and anodically coloring counter electrode layer 410.
• cathodically coloring electrochromic layer 406 includes two sublayers 406a and 406b.
• the first sublayer 406a may include a known electrochromic cathodically coloring material such as tungsten oxide or tungsten molybdenum oxide.
• the second sublayer 406b may include one or more different elements such as a case where sublayer 406a contains tungsten, molybdenum, and oxygen but sublayer 406b contains only tungsten and oxygen or vice versa.
• sublayers 406a and 406b include the same elements, but at different relative concentrations.
• both sublayers may contain tungsten, molybdenum, and oxygen, but sublayer 406a is stoichiometric or substoichiometric in oxygen while sublayer 406b is superstoichiometric in oxygen.
• a second sublayer e.g., sublayer 406b
• sublayer 406b may be expressed as WO v , where y is greater than 3 or as Wi- ⁇ Mo ⁇ O , where y is greater than 3.1n certain embodiments, an IC layer (not shown in Figure 4) is disposed between the electrochromic layer 406 and the counter electrode layers 410. In certain embodiments, the second sublayer 406b converts, at least partially, to function as an IC layer.
• FIG. 5 shows an additional example of an electrochromic stack that includes transparent conductive oxide layers 504 and 514, cathodically coloring electrochromic layer 606, and anodically coloring counter electrode layer 511.
• counter electrode layer 511 includes three sublayers 511a-c.
• the first sublayer 511a may be a flash layer.
• Each of the sublayers 51 la-c may have a different composition. Or any two or three of them may have the same composition.
• the second and third sublayers 511b and 511c may include the same elements at different relative concentrations in some embodiments. In another embodiment, all of the sublayers 51 la-c include the same elements at different relative concentrations.
• the first sublayer 511a may be a first anodically coloring counter electrode material
• the second and third sublayers 511b and 511c may be a second anodically coloring counter electrode material (each deposited at a different composition).
• the composition of the second and third sublayers 511b and 511c may be homogeneous within each sublayer.
• the cathodically coloring electrochromic layer 506 includes two sublayers 506a and 506b.
• the first sublayer 506a may include a known electrochromic cathodically coloring material such as tungsten oxide or tungsten molybdenum oxide.
• the second sublayer 506b may include one or more different elements such as a case where sublayer 506a contains tungsten, molybdenum, and oxygen but sublayer 506b contains only tungsten and oxygen.
• sublayers 506a and 506b include the same elements, but at different relative concentrations. For example, both sublayers may contain tungsten, molybdenum, and oxygen, but sublayer 506a is stoichiometric or substoichiometric in oxygen while sublayer 506b is superstoichiometric in oxygen.
• the first counter electrode sublayer is a flash layer, which is generally characterized as a thin and often quickly deposited layer typically having a thickness of not greater than about 100 nm, in various cases not greater than about 80 nm.
• a flash layer may be between about 5 nm thick and about 100 nm thick, between about 10 nm thick and about 80 nm thick, or between about 10 nm thick and about 50 nm thick, or about 10 nm and about 30 nm thick.
• a separate flash layer (which may be an anodically coloring counter electrode material) may be provided between the electrochromic layer and the first sublayer of the counter electrode.
• a flash layer may be provided between the second sublayer and the transparent conductor layer.
• a flash layer if present, may or may not exhibit electrochromic properties.
• a flash layer is made of a counter electrode material that does not change color with remaining electrochromic/counter electrode layers (though this layer may have a composition that is very similar to other layers such as an anodically coloring layer).
• the first sublayer whether a flash layer or thicker than a flash layer, has a relatively high electronic resistivity, for example between about 1 and 5x10 10 Ohm-cm.
• a third counter electrode is a defect-mitigating insulating layer as described elsewhere herein.
• the electrochromic stack has an optional cap layer that may be disposed between the counter electrode layer (or the electrochromic layer if it is separated from the substrate by the counter electrode layer) and the second transparent conductive layer.
• the cap layer has a composition matching or similar to the counter electrode layer or a sublayer therein.
• the cap layer comprises a nickel tungsten oxide, e.g., NiWO.
• the cap layer is about 0 to 50 nm thick.
• the cap layer serves as a defect- mitigating insulating layer.
• the electrochromic stack includes a hermetic layer over the second conductive layer.
• the hermetic layer may comprise a silicon oxide, a silicon oxynitride, a silicon nitride, a silicon aluminum oxide, an aluminum oxide, an aluminum nitride, an aluminum zinc oxide, a tin oxide, carbon (e.g., graphene, graphite, diamond-like carbon, and/or fluorinated diamond-like carbon), a titanium oxide, a titanium nitride, a tantalum nitride, a tin oxide, a zinc oxide, chromium, an organic polymer (e.g., a parylene polymer), and mixtures thereof.
• an organic polymer e.g., a parylene polymer
• a hermetic layer has a thickness of about 50 nm to 5 micrometers, or about 100 nm to 3 micrometers, or about 100 nm to 1 micrometer.
• Table 1 below presents information for electrochromic device stacks in accordance with certain embodiments.
• Formation of electrochromic devices and electrochromic device precursors involves deposition of a number of different layers on a substrate. Each of these layers is discussed above. A number of other steps may also be taken when fabricating an electrochromic device or precursor, as described in Figure 2A, for example.
• an electrochromic device precursor is a partially fabricated electrochromic device which is not yet suitable for functioning as a finished electrochromic device.
• an electrochromic device precursor includes at least a first conductive layer, an electrochromic layer, a counter electrode layer, and a second conductive layer. Additional layers may be present in some cases.
• an electrochromic device precursor has materials within its structure that, although not suitable for function as a finished device, are configured or suited for physical and/or chemical conversion to become a functioning device. Such device precursors may be desirable, e.g., in cases where substrates are coated with the precursor materials, stored or shipped to another facility, for later and/or downstream processing.
• a separate ion conducting layer may not be present in certain embodiments.
• the electrochromic device precursor may lack any layer or region that would serve the purpose of an ion conducting layer (e.g., allowing passage of ions but not electrons between the electrochromic layer and the counter electrode layer).
• An electrochromic device precursor can be further processed to form an electrochromic device.
• this further processing may form a material that is ionically conductive and substantially electronically insulating in an interfacial region between the electrochromic layer and the counter electrode layer. In various embodiments, this further processing may involve thermal conditioning, as described further below.
• one or both of the electrochromic and counter electrode material are superstoichiometrically oxygenated at the interface of the layers, or otherwise an excess of oxygen or other reactive species is present between the layers.
• the superstoichiometrically oxygenated material may later be converted to the material that is ionically conductive and substantially electronically insulating.
• further processing may involve lithiation of one or more layers in the electrochromic device, either through direct lithium deposition or through diffusion.
• the lithium added reacts or otherwise combines with the oxygen or other reactive species at the interface to form an ion conducting and electronically insulating material at the interface between the electrochromic and counter electrode material layers.
• this further processing may involve flowing current between electrochromic and counter electrode layers. Any one or more of these further processing steps may be involved in formation of an electrochromic device from an electrochromic device precursor in certain implementations .
• Figure 2A is a process flow, 200, describing aspects of a method of fabricating an electrochromic device or other optical device having opposing bus bars, each applied to one of the conductive layers of the optical device.
• the dotted lines denote optional steps in the process flow.
• An exemplary device, 240 as described in relation to Figures 2B-C, is used to illustrate the process flow.
• Figure 2B provides top views depicting the fabrication of device 240 including numerical indicators of process flow 200 as described in relation to Figure 2A.
• Figure 2C shows cross-sections of the lite including device 240 described in relation to Figure 2B.
• Device 240 is a rectangular device, but process flow 200 applies to any shape of optical device having opposing bus bars, each on one of the conductive layers.
• process flow 200 begins with an optional polishing of the first conductive layer, see 201. Polishing, if performed, may be done prior to an edge deletion, see 205, and/or after an edge deletion in the process flow. [0114] Referring again to Figure 2A, if polishing 201 is not performed, process 200 begins with edge deleting a first width about a portion of the perimeter of the substrate, see 205. The edge deletion may remove only the first conductive layer or may also remove a diffusion barrier, if present.
• the substrate is glass and includes a sodium diffusion barrier and a transparent conducting layer thereon, e.g.
• a width A is removed from three sides of the perimeter of substrate 230. This width is typically, but not necessarily, a uniform width.
• a second width, B is described below. Where width A and/or width B are not uniform, then their relative magnitudes with respect to each other are in terms of their average width.
• edge tapering As a result of the removal of the first width A at 205, there is a newly exposed edge of the lower conductive layer.
• this edge of the first conductive layer may be optionally tapered, see 207 and 209.
• the underlying diffusion barrier layer may also be tapered. Tapering the edge of one or more device layers, prior to fabricating subsequent layers thereon, has unexpected advantages in device structure and performance.
• the edge tapering process is described in more detail in U.S. Patent No. 9,454,053, which is herein incorporated by reference in its entirety. Although edge tapering is shown at both 207 and 209 in Figure 2A, if performed, edge tapering would typically be performed once (e.g., at 207 or 209).
• the lower conductive layer is optionally polished before or after edge tapering, see 208.
• the EC device is deposited over the surface of substrate 230, see 210.
• This EC stack deposition is further described in relation to Figure 2D.
• This deposition includes one or more material layers of the optical device and the second conducting layer, e.g. a transparent conducting layer such as indium tin oxide (ITO).
• ITO indium tin oxide
• the depicted coverage is the entire substrate, but there could be some masking due to a carrier that must hold the glass in place.
• the entire area of the remaining portion of the first conductive layer is covered including overlapping the first conductor about the first width A previously removed. This allows for overlapping regions in the final device architecture.
• electromagnetic radiation is used to perform edge deletion and provide a peripheral region of the substrate, e.g., to remove transparent conductive layer or more layers (up to and including the top conductive layer and any vapor barrier applied thereto), depending upon the process step.
• the edge deletion is performed at least to remove material including the transparent conductive layer on the substrate, and optionally also removing a diffusion barrier if present.
• edge deletion is used to remove a surface portion of the substrate, e.g., float glass, and may go to a depth not to exceed the thickness of the compression zone.
• Edge deletion is performed, e.g., to create a good surface for sealing by at least a portion of the primary seal and the secondary seal of the IGU.
• a transparent conductive layer can sometimes lose adhesion when the conductive layer spans the entire area of the substrate and thus has an exposed edge, despite the presence of a secondary seal. Also, it is believed that when metal oxide and other functional layers have such exposed edges, they can serve as a pathway for moisture to enter the bulk device and thus compromise the primary and secondary seals.
• Edge deletion is described herein as being performed on a substrate that is already cut to size. However, edge deletion can be done before a substrate is cut from a bulk glass sheet in other disclosed embodiments. For example, non-tempered float glass may be cut into individual lites after an EC device is patterned thereon. Methods described herein can be performed on a bulk sheet and then the sheet cut into individual EC lites. In certain embodiments, edge deletion may be carried out in some edge areas prior to cutting the EC lites, and again after they are cut from the bulk sheet. In certain embodiments, all edge deletion is performed prior to excising the lites from the bulk sheet.
• portions of the coating on the glass sheet can be removed in anticipation of where the cuts (and thus edges) of the newly formed EC lites will be. In other words, there is no actual substrate edge yet, only a defined area where a cut will be made to produce an edge.
• “edge deletion” is meant to include removing one or more material layers in areas where a substrate edge is anticipated to exist.
• Exemplary electromagnetic radiation includes UV, lasers, and the like.
• material may be removed with directed and focused energy at one or more of the wavelengths 248 nm, 355 nm (UV), 1030 nm (IR, e.g. disk laser), 1064 nm (e.g. Nd:YAG laser), and 532 nm (e.g. green laser).
• Laser irradiation is delivered to the substrate using, e.g. optical fiber or open beam path.
• the ablation can be performed from either the substrate side or the EC film side depending on the choice of the substrate handling equipment and configuration parameters.
• the energy density required to ablate the film thickness is achieved by passing the laser beam through an optical lens. The lens focuses the laser beam to the desired shape and size.
• a“top hat” beam configuration is used, e.g., having a focus area of between about 0.005 mm 2 to about 2 mm 2 .
• the focusing level of the beam is used to achieve the required energy density to ablate the EC film stack.
• the energy density used in the ablation is between about 2 J/cm 2 and about 6 J/cm 2 .
• a laser spot is scanned over the surface of the EC device, along the periphery.
• the laser spot is scanned using a scanning F theta lens.
• Homogeneous removal of the EC film is achieved, e.g., by overlapping the spots’ area during scanning.
• the overlap is between about 5% and about 100%, in another embodiment between about 10% and about 90%, in yet another embodiment between about 10% and about 80%.
• Various scanning patterns may be used, e.g., scanning in straight lines, curved lines, and various patterns may be scanned, e.g., rectangular or other shaped sections are scanned which, collectively, create the peripheral edge deletion area.
• the scanning lines are overlapped at the levels described above for spot overlap. That is, the area of the ablated material defined by the path of the line previously scanned is overlapped with later scan lines so that there is overlap. That is, a pattern area ablated by overlapping or adjacent laser spots is overlapped with the area of a subsequent ablation pattern.
• a higher frequency laser e.g. in the range of between about 11 KHz and about 500 KHz, may be used.
• the pulse duration is between about 100 fs (femtosecond) and about 100 ns (nanosecond), in another embodiment the pulse duration is between about 1 ps (picosecond) and about 50 ns, in yet another embodiment the pulse duration is between about 20 ps and about 30 ns. Pulse duration of other ranges can be used in other embodiments.
• process flow 200 continues with removing a second width, B, narrower than the first width A, about substantially the entire perimeter of the substrate, see 215. This may include removing material down to the glass or to a diffusion barrier, if present.
• process flow 200 is complete up to 215, e.g. on a rectangular substrate as depicted in Figure 2B, there is a perimeter area, with width B, where there is none of the first transparent conductor, the one or more material layers of the device, or the second conducting layer -removing width B has exposed diffusion barrier or substrate.
• the device stack including the first transparent conductor surrounded on three sides by overlapping one or more material layers and the second conductive layer.
• the remaining side there is no overlapping portion of the one or more material layers and the second conductive layer. It is proximate this remaining side (e.g., bottom side in Figure 2B) that the one or more material layers and the second conductive layer are removed in order to expose a portion (bus bar pad expose, or“BPE”), 235, of the first conductive layer, see 220.
• the BPE 235 need not run the entire length of that side, it need only be long enough to accommodate the bus bar and leave some space between the bus bar and the second conductive layer so as not to short on the second conductive layer. In one embodiment, the BPE 235 spans the length of the first conductive layer on that side.
• a BPE is where a portion of the material layers are removed down to the lower electrode or other conductive layer (e.g. a transparent conducting oxide layer), in order to create a surface for a bus bar to be applied and thus make electrical contact with the electrode.
• the bus bar applied can be a soldered bus bar, and ink bus bar and the like.
• a BPE typically has a rectangular area, but this is not necessary; the BPE may be any geometrical shape or an irregular shape.
• a BPE may be circular, triangular, oval, trapezoidal, and other polygonal shapes. The shape may be dependent on the configuration of the EC device, the substrate bearing the EC device (e.g.
• the BPE spans at least about 50% of the length of one side of an EC device. In one embodiment, the BPE spans at least about 80% of the length of one side of an EC device. Typically, but not necessarily, the BPE is wide enough to accommodate the bus bar, but should allow for some space at least between the active EC device stack and the bus bar.
• the BPE is substantially rectangular, the length approximating one side of the EC device and the width is between about 5 mm and about 15 mm, in another embodiment between about 5 mm and about 10 mm, and in yet another embodiment between about 7 mm and about 9 mm.
• a bus bar may be between about 1 mm and about 5 mm wide, typically about 3 mm wide.
• the BPE is fabricated wide enough to accommodate the bus bar’ s width and also leave space between the bus bar and the EC device (as the bus bar is only supposed to touch the lower conductive layer).
• the bus bar width may exceed that of the BPE (and thus there is bus bar material touching both the lower conductor and glass (and/or diffusion barrier) on area 241), as long as there is space between the bus bar and the EC device (in embodiments where there is an L3 isolation scribe, the bus bar may contact the deactivated portion).
• the outer edge, along the length, of the bus bar may be aligned with the outer edge of the BPE, or inset by about 1 mm to about 3 mm.
• the space between the bus bar and the EC device is between about 1 mm and about 3 mm, in another embodiment between about 1 mm and 2 mm, and in another embodiment about 1.5 mm. Formation of BPEs is described in more detail below, with respect to an EC device having a lower electrode that is a TCO. This is for convenience only, the electrode could be any suitable electrode for an optical device, transparent or not.
• an area of the bottom TCO (e.g. first TCO) is cleared of deposited material so that a bus bar can be fabricated on the TCO.
• this is achieved by laser processing which selectively removes the deposited film layers while leaving the bottom TCO exposed in a defined area at a defined location.
• the absorption characteristics of the bottom electrode and the deposited layers are exploited in order to achieve selectivity during laser ablation, that is, so that the EC materials on the TCO are selectively removed while leaving the TCO material intact.
• an upper portion (depth) of the TCO layer is also removed in order to ensure good electrical contact of the bus bar, e.g., by removing any mixture of TCO and EC materials that might have occurred during deposition.
• the need for an L3 isolation scribe line to limit leakage currents can be avoided - this eliminates a process step, while achieving the desired device performance results.
• the electromagnetic radiation used to fabricate a BPE is the same as described above for performing edge deletion.
• the (laser) radiation is delivered to the substrate using either optical fiber or the open beam path.
• the ablation can be performed from either glass side or the film side depending on the choice of the electromagnetic radiation wavelength.
• the energy density required to ablate the film thickness is achieved by passing the laser beam through an optical lens.
• the lens focuses the laser beam to the desired shape and size, e.g. a“top hat” having the dimensions described above, in one embodiment, having an energy density of between about 0.5 J/cm 2 and about 4 J/cm 2 .
• laser scan overlapping for BPE is done as described above for laser edge deletion.
• variable depth ablation is used for BPE fabrication.
• the laser processing at the focal plane results in some amount (between about 10 nm and about 100 nm) of residue, e.g. tungsten oxide, remaining on the exposed area of the lower conductor. Since many EC materials are not as conductive as the underlying conductive layer, the bus bar fabricated on this residue does not make full contact with the underlying conductor, resulting in voltage drop across the bus bar to lower conductor interface. The voltage drop impacts coloration of the device as well as impacts the adhesion of the bus bar to the lower conductor.
• residue e.g. tungsten oxide
• the laser ablation above the focal plane is performed, i.e. the laser beam is defocused.
• the defocusing profile of the laser beam is a modified top hat, or“quasi top hat.”
• bus bars are applied to the device, one on exposed area 235 of the first conductive layer (e.g., first TCO) and one on the opposite side of the device, on the second conductive layer (e.g., second TCO), on a portion of the second conductive layer that is not above the first conductive layer, see 225.
• This placement of the bus bar 1 on the second conductive layer avoids coloration under the bus bar and the other associated issues with having a functional device under this bus bar.
• there are no laser isolation scribes necessary in fabrication of the device - this is a radical departure from conventional fabrication methods, where one or more isolation scribes leave non- functional device portions remaining in the final construct.
• Figure 2B indicates cross-section cuts Z-Z’ and W-W’ of device 240.
• the cross-sectional views of device 240 at Z-Z’ and W-W’ are shown in Figure 2C.
• the depicted layers and dimensions are not to scale, but are meant to represent functionally the configuration.
• the diffusion barrier was removed when width A and width B were fabricated.
• perimeter area 241 is free of first conductive layer and diffusion barrier; although in one embodiment the diffusion barrier is left intact to the edge of the substrate about the perimeter on one or more sides.
• the diffusion barrier is co-extensive with the one or more material layers and the second conductive layer (thus width A is fabricated at a depth to the diffusion barrier, and width B is fabricated to a depth sufficient to remove the diffusion barrier).
• width A is fabricated at a depth to the diffusion barrier
• width B is fabricated to a depth sufficient to remove the diffusion barrier.
• bus bar 1 is fabricated on one of these overlapping portions, on the second TCO.
• a vapor barrier layer is fabricated co-extensive with the second conductive layer.
• a vapor barrier is typically highly transparent, e.g. aluminum zinc oxide, a tin oxide, silicon dioxide and mixtures thereof, amorphous, crystalline or mixed amorphous-crystalline.
• the vapor barrier layer is also electrically conductive, and exposure of the second conductive layer need not be performed, i.e. the bus bar may be fabricated on the vapor barrier layer.
• the vapor barrier layer may be ITO, e.g. amorphous GGO, and thus be sufficiently electrically conductive for this purpose.
• the amorphous morphology of the vapor barrier may provide greater hermeticity than a crystalline morphology.
• the vapor barrier may be deposited using chemical vapor deposition (CVD) or atomic layer deposition (ALD), and may include a metal nitride that is electrically conductive, a silicon nitride, a silicon oxide or mixtures thereof.
• CVD chemical vapor deposition
• ALD atomic layer deposition
• Figure 2D provides another flowchart describing a method of fabricating an electrochromic device or precursor according to certain embodiments.
• the method described in Figure 2D focuses on the deposition steps.
• the method 260 begins by either (a) receiving a substrate having a first conductive layer thereon, or (b) depositing the first conductive layer on the substrate, see 261.
• the substrate includes the first conductive layer thereon, and there is no need to separately deposit the first conductive layer.
• the conductive layer may be deposited prior to deposition of the remaining layers. Deposition of the second conductive layer is discussed further below. In certain embodiments, these details may also apply to the deposition of the first conductive layer.
• the method continues with deposition of the electrochromic layer, see 263.
• the electrochromic layer is formed through sputtering.
• the following conditions may be used to deposit the electrochromic layer.
• the electrochromic layer may be formed by sputtering using one or more metal-containing targets and a sputter gas including between about 40% and about 80% O2 and between about 20% and about 60% Ar.
• Each target may include one or more metals such as tungsten and molybdenum.
• the substrate upon which the electrochromic layer is deposited may be heated, at least intermittently, to between about 150°C and about 450°C (in some cases between about 250°C and 350°C) during formation of the electrochromic layer.
• the electrochromic layer may be deposited to a thickness between about 500 and 600 nm.
• the electrochromic layer may be deposited as two or more layers or a graded layer.
• One of the layers or a portion of the graded layer may be oxygen-rich in comparison to the other layer or the remainder of the graded layer.
• the oxygen-rich portion may be superstoichiometric with respect to oxygen.
• the oxygen-rich layer or portion is in contact with the counter electrode layer.
• the oxygen rich material at the interface may be supplied in the form of the counter electrode material instead of or in addition to the electrochromic material.
• the first layer of the electrochromic layer may be between about 350 nm and about 450 nm thick.
• the first layer may be formed through sputtering using one or more targets and a first sputter gas including between about 40% and about 80% O2 and between about 20% Ar and about 60% Ar.
• the targets may include one or more metal such as tungsten and molybdenum.
• the second layer may be between about 100 nm and about 200 nm thick.
• the second layer may be formed through sputtering using one or more targets and a second sputter gas including between about 70% and 100% O2 and between 0% Ar and about 30% Ar.
• heat may be applied, for example by heating substrate, at least intermittently, to between about 150°C and about 450°C during deposition of the first electrochromic layer, but not (or substantially not) heating during deposition of the second electrochromic layer.
• the first electrochromic layer is about 400 nm thick; the first sputter gas includes between about 50% and about 60% O2 and between about 40% and about 50% Ar; the second electrochromic layer is about 150 nm thick; and the second sputter gas is substantially pure O2.
• heat is applied, at least intermittently, to between about 200°C and about 350°C during formation of the first electrochromic layer but not (or substantially not) during formation of the second electrochromic layer.
• the electrochromic layer may be deposited as a graded layer with a graded oxygen composition, the following conditions may be used to deposit the electrochromic layer.
• the electrochromic layer may be formed through sputtering using one or more metal-containing targets and a sputter gas, where the sputter gas includes between about 40% and about 80% O2 and between about 20% and about 60% Ar at the start of sputtering the electrochromic layer, and the sputter gas includes between about 70% and 100% O2 and between 0% and about 30% Ar at the end of sputtering the electrochromic layer.
• the substrate may be heated, at least intermittently, to between about 200°C and about 350°C at the beginning of formation of the electrochromic layer, but not heated during deposition of at least a final portion of the electrochromic layer.
• This description assumes that the electrochromic layer is deposited before the counter electrode layer, as shown in Figure 2D. In cases where the electrochromic layer is deposited as a graded layer after formation of the counter electrode layer, the details regarding the“initial”/“start” and “final”/”end” portions of the sputtering may be reversed. In either case, the electrochromic material with the higher oxygen concentration may be in contact with the counter electrode layer.
• the pressure in the deposition station or chamber during formation of the electrochromic layer may be between about 1 and about 75 mTorr, or between about 5 and about 50 mTorr, or between about 10 and about 20 mTorr.
• the power density used to sputter the one or more targets may be between about 2 Watts/cm 2 and about 50 Watts/cm 2 (determined based on the power applied divided by the surface area of the target); in another embodiment between about 10 Watts/cm 2 and about 20 Watts/cm 2 ; and in yet another embodiment between about 15 Watts/cm 2 and about 20 Watts/cm 2 .
• the power delivered to effect sputtering is provided via direct current (DC).
• DC direct current
• pulsed DC/ AC reactive sputtering is used.
• the frequency is between about 20 kHz and about 400 kHz, in another embodiment between about 20 kHz and about 50 kHz, in yet another embodiment between about 40 kHz and about 50 kHz, in another embodiment about 40 kHz.
• the above conditions may be used in any combination with one another to effect deposition of a high quality electrochromic layer.
• the distance between the target (cathode or source) to the substrate surface is between about 35 mm and about 150 mm; in another embodiment between about 45 mm and about 130 mm; and in another embodiment between about 70 mm and about 100 mm. These same distances may apply to other targets used to deposit other layers of the device.
• the method continues with the optional deposition of the ion conducting layer, see 263.
• the ion conducting layer may be provided in a number of different ways.
• the ion conductor layer may be formed through sputtering, vapor-based techniques, sol-gel techniques, etc. In many cases, the ion conducting layer is omitted.
• the method continues with deposition of the counter electrode layer, see 267.
• the counter electrode layer may be deposited as a homogenous layer, two or more layers, or a graded layer.
• one of the layers or a portion of the graded layer may be oxygen-rich in comparison to the other layer or the remaining portion of the graded layer.
• the oxygen-rich layer or portion may be positioned in direct physical contact with the electrochromic material in the electrochromic layer.
• the deposition conditions may change between depositing the first layer and the second layer, or between depositing the initial portion of the graded layer and the final portion of the graded layer.
• the oxygen concentrations and substrate temperatures recited above with respect to deposition of an electrochromic layer may also apply to deposition of a counter electrode layer in various embodiments.
• the layer or the portion of the graded layer that is oxygen-rich may be formed using a sputter gas having a higher concentration of oxygen and a lower concentration of inert gas compared to the sputter gas used to deposit the other layer or the remaining portion of the graded layer.
• a sputter gas used to form the counter electrode may include between about 30% and about 100% oxygen, in another embodiment between about 80% and about 100% oxygen, in yet another embodiment between about 95% and about 100% oxygen, in another embodiment about 100% oxygen.
• the power density used to sputter the CE target is between about 2 Watts/cm 2 and about 50 Watts/cm 2 (determined based on the power applied divided by the surface area of the target); in another embodiment between about 5 Watts/cm 2 and about 20 Watts/cm 2 ; and in yet another embodiment between about 8 Watts/cm 2 and about 10 Watts/cm 2 , in another embodiment about 8 Watts/cm 2 .
• the power delivered to effect sputtering is provided via direct current (DC).
• DC direct current
• pulsed DC/ AC reactive sputtering is used.
• the frequency is between about 20 kHz and about 400 kHz, in another embodiment between about 20 kHz and about 50 kHz, in yet another embodiment between about 40 kHz and about 50 kHz, in another embodiment about 40 kHz.
• the pressure in the deposition station or chamber in one embodiment, is between about 1 and about 50 mTorr, in another embodiment between about 20 and about 40 mTorr, in another embodiment between about 25 and about 35 mTorr, in another embodiment about 30 mTorr.
• the counter electrode layer is deposited to a thickness of between about 150 and 350 nm; in yet another embodiment between about 200 and about 250 nm thick.
• the method continues with deposition of the second conductive layer, see 269.
• the recited conditions may be employed to form a thin, low-defect layer of indium tin oxide by sputtering a target containing indium oxide in tin oxide, e.g. with an argon sputter gas with or without oxygen.
• the thickness of the TCO layer is between about 5 nm and about 10,000 nm, in another embodiment between about 10 nm and about 1,000 nm; in yet another embodiment between about 10 nm and about 500 nm.
• the substrate temperature during deposition of the second conducting layer is between about 20°C and about 300°C, in another embodiment between about 20°C and about 250°C, and in another embodiment between about 80°C and about 225°C.
• depositing the TCO layer includes sputtering a target including between about 80% (by weight) to about 99% of I CT and between about 1% and about 20% Sn0 2 using an inert gas, optionally with oxygen.
• the target is between about 85% (by weight) to about 97% of I Ch and between about 3% and about 15% Sn0 2 .
• the target is about 90% of I n 2 O3 and about 10% Sn0 2 -
• the gas composition contains between about 0.1% and about 3% oxygen, in another embodiment between about 0.5% and about 2% oxygen, in yet another embodiment between about 1% and about 1.5% oxygen, in another embodiment about 1.2% oxygen.
• the power density used to sputter the TCO target is between about 0.5 Watts/cm 2 and about 10 Watts/cm 2 (determined based on the power applied divided by the surface area of the target); in another embodiment between about 0.5 Watts/cm 2 and about 2 Watts/cm 2 ; and in yet another embodiment between about 0.5 Watts/cm 2 and about 1 Watts/cm 2 , in another embodiment about 0.7 Watts/cm 2 .
• the power delivered to effect sputtering is provided via direct current (DC). In other embodiments, pulsed DC/ AC reactive sputtering is used.
• the frequency is between about 20 kHz and about 400 kHz, in another embodiment between about 50 kHz and about 100 kHz, in yet another embodiment between about 60 kHz and about 90 kHz, in another embodiment about 80 kHz.
• the pressure in the deposition station or chamber in one embodiment, is between about 1 and about 10 mTorr, in another embodiment between about 2 and about 5 mTorr, in another embodiment between about 3 and about 4 mTorr, in another embodiment about 3.5 mTorr.
• the indium tin oxide layer is between about 20% (atomic) In and about 40% In; between about 2.5% Sn and about 12.5% Sn; and between about 50% O and about 70% O; in another embodiment, between about 25% In and about 35% In; between about 5.5% Sn and about 8.5% Sn; and between about 55% O and about 65% O; and in another embodiment, about 30% In, about 8% Sn; and about 62% O.
• the above conditions may be used in any combination with one another to effect deposition of a high quality indium tin oxide layer.
• one or more of the deposited layers may be lithiated prior to deposition of the next layer.
• one or more of the electrochromic layer, the optional ion conducting layer, and the counter electrode layer may be lithiated.
• the electrochromic layer is lithiated.
• the counter electrode layer is lithiated.
• the ion conductor layer is lithiated.
• both the electrochromic layer and the counter electrode layer are lithiated.
• the electrochromic layer, counter electrode layer, and ion conducting layer are all lithiated.
• the electrochromic layer and the ion conductor layer are lithiated.
• the counter electrode layer and the ion conducing layer are lithiated. Further, any of these layers may be lithiated during deposition of that layer. In some cases, one portion of a layer may be deposited, then lithiated, and then the remaining portion of that layer may be deposited. In one example, a first portion of the electrochromic layer is deposited, then lithiated, and then a second portion of the electrochromic layer is deposited. In another example, a first portion of the counter electrode layer is deposited, then lithiated, and then a second portion of the counter electrode layer is deposited. These first and second portions of the relevant layer may be deposited according to the same conditions, or different conditions. In some cases, the first and second portions of the relevant layer may have different compositions.
• lithiation of the electrochromic and/or counter electrode layers may promote formation of an interfacial region between the electrochromic layer and the counter electrode layer, where the interfacial region includes material that is ionically conductive and substantially electronically insulating.
• the lithium intercalation and subsequent heating allows a chemical change at the interface between the two electrode materials (e.g., between the electrochromic material and the counter electrode material), forming an ionically conductive and electrically insulating material in an interfacial region between the electrochromic layer and the counter electrode layer.
• the multi- step thermal conditioning as described herein may promote formation of the ionically conductive and electrically insulating material.
• the operations shown in Figure 2D may be used to form an electrochromic device precursor in various embodiments.
• one or more steps may be taken as described above.
• one technique that may be used to form an electrochromic device from an electrochromic device precursor is multi-step thermal conditioning.
• the conditioning may involve a series of heating operations including heating the substrate under an inert atmosphere, heating the substrate under oxygen atmosphere, and heating the substrate in air.
• stacks formed as described in Figure 2D are heated (either before or after depositing the second conductive layer at 269) at between about 150°C and about 450°C, for between about 10 minutes and about 30 minutes under Ar, and then for between about 1 minute and about 15 minutes under O2.
• the stack is processed further by heating the stack in air at between about 250 °C and about 350 °C, for between about 20 minutes and about 40 minutes.
• the stack is processed by heating the stack at about 250°C for about 15 minutes under inert atmosphere, followed by 5 minutes under O2 atmosphere, then heating the stack in air at about 300°C for about 30 minutes.
• Flowing a current between the electrochromic layer and the counter electrode layer as part of an initial activation cycle of the electrochromic device can also be performed.
• An integrated deposition system may be employed to fabricate electrochromic devices on, for example, architectural glass or other substrates.
• the electrochromic devices may be used to make insulated glass units (IGUs) which in turn may be used to make electrochromic windows.
• IGUs insulated glass units
• integrated deposition system means an apparatus for fabricating electrochromic devices on optically transparent and translucent substrates.
• the apparatus has multiple stations, each devoted to a particular unit operation such as depositing a particular component (or portion of a component) of an electrochromic device, as well as cleaning, etching, and temperature control of such device or portion thereof.
• the multiple stations are fully integrated such that a substrate on which an electrochromic device is being fabricated can pass from one station to the next without being exposed to an external environment.
• Integrated deposition systems operate with a controlled ambient environment inside the system where the process stations are located.
• a fully integrated system allows for better control of interfacial quality between the layers deposited.
• Interfacial quality refers to, among other factors, the quality of the adhesion between layers and the lack of contaminants in the interfacial region.
• the term“controlled ambient environment” means a sealed environment separate from an external environment such as an open atmospheric environment or a clean room. In a controlled ambient environment at least one of pressure and gas composition is controlled independently of the conditions in the external environment. Generally, though not necessarily, a controlled ambient environment has a pressure below atmospheric pressure; e.g., at least a partial vacuum. The conditions in a controlled ambient environment may remain constant during a processing operation or may vary over time.
• a layer of an electrochromic device may be deposited under vacuum in a controlled ambient environment and at the conclusion of the deposition operation, the environment may be backfilled with purge or reagent gas and the pressure increased to, e.g., atmospheric pressure for processing at another station, and then a vacuum reestablished for the next operation and so forth.
• the system includes a plurality of deposition stations aligned in series and interconnected and operable to pass a substrate from one station to the next without exposing the substrate to an external environment.
• the plurality of deposition stations comprise (i) a first deposition station containing one or more targets for depositing a cathodically coloring electrochromic layer; (ii) a second optional deposition station containing one or more targets for depositing an ion conducting layer; and (iii) a third deposition station containing one or more targets for depositing a counter electrode layer.
• the second deposition station may be omitted in certain cases. For instance, the apparatus may not include any target for depositing a separate ion conductor layer.
• the system also includes a controller containing program instructions for passing the substrate through the plurality of stations in a manner that sequentially deposits on the substrate (i) an electrochromic layer, (ii) an (optional) ion conducting layer, and (iii) a counter electrode layer to form a stack.
• the layers may be formed in different stations or in the same station, depending on the desired composition of each layer, among other factors.
• a first station may be used to deposit the electrochromic layer
• a second station may be used to deposit a first layer of the counter electrode layer
• a third station may be used to deposit a second layer of the counter electrode layer.
• the plurality of deposition stations are operable to pass a substrate from one station to the next without breaking vacuum.
• the plurality of deposition stations are configured to deposit the electrochromic layer, the optional ion conducting layer, and the counter electrode layer on an architectural glass substrate.
• the integrated deposition system includes a substrate holder and transport mechanism operable to hold the architectural glass substrate in a vertical orientation while in the plurality of deposition stations.
• the integrated deposition system includes one or more load locks for passing the substrate between an external environment and the integrated deposition system.
• the plurality of deposition stations include at least two stations for depositing a layer selected from the group consisting of the electrochromic layer, the ion conducting layer, and the counter electrode layer.
• the integrated deposition system includes one or more lithium deposition stations, each including a lithium containing target.
• the integrated deposition system contains two or more lithium deposition stations.
• the integrated deposition system has one or more isolation valves for isolating individual process stations from each other during operation.
• the one or more lithium deposition stations have isolation valves.
• isolation valves means devices to isolate depositions or other processes being carried out one station from processes at other stations in the integrated deposition system.
• isolation valves are physical (solid) isolation valves within the integrated deposition system that engage while the lithium is deposited.
• isolation valves may be gas knifes or shields, e.g., a partial pressure of argon or other inert gas is passed over areas between the lithium deposition station and other stations to block ion flow to the other stations.
• isolation valves may be an evacuated regions between the lithium deposition station and other process stations, so that lithium ions or ions from other stations entering the evacuated region are removed to, e.g., a waste stream rather than contaminating adjoining processes.
• isolation valves are not limited to lithium deposition stations.
• the integrated deposition system includes one or more stations for depositing a conductive layer (e.g., a transparent conductive oxide layer, sometimes referred to as TCO).
• a conductive layer e.g., a transparent conductive oxide layer, sometimes referred to as TCO.
• two stations may be provided, each dedicated to depositing one of the conductive layers.
• a single station may be used to deposit both conductive layers.
• only a single conductive layer deposition station is needed. For instance, in many cases the substrate is received with the first conductive layer provided thereon, and only the second conductive layer is deposited during fabrication of the electrochromic device.
• FIG. 3A depicts in schematic fashion an integrated deposition system 300 in accordance with certain embodiments.
• system 300 includes an entry load lock, 302, for introducing the substrate to the system, and an exit load lock, 304, for removal of the substrate from the system.
• the load locks allow substrates to be introduced and removed from the system without disturbing the controlled ambient environment of the system.
• Integrated deposition system 300 has a module, 306, with a plurality of deposition stations; an EC layer deposition station, an IC layer deposition station and a CE layer deposition station.
• integrated deposition systems need not have load locks, e.g., module 306 could alone serve as the integrated deposition system.
• the substrate may be loaded into module 306, the controlled ambient environment established and then the substrate processed through various stations within the system.
• Individual stations within an integrated deposition systems can contain heaters, coolers, various sputter targets and means to move them, RF and/or DC power sources and power delivery mechanisms, etching tools e.g. plasma etch, gas sources, vacuum sources, glow discharge sources, process parameter monitors and sensors, robotics, power supplies, and the like.
• FIG. 3B depicts a segment (or simplified version) of integrated deposition system 300 in a perspective view and with more detail including a cutaway view of the interior.
• system 300 is modular, where entry load lock 302 and exit load lock 304 are connected to deposition module 306.
• entry port, 310 for loading, for example, architectural glass substrate 325 (load lock 304 has a corresponding exit port).
• Substrate 325 is supported by a pallet, 320, which travels along a track, 315.
• pallet 320 is supported by track 315 via hanging but pallet 320 could also be supported atop a track located near the bottom of apparatus 300 or a track, e.g. mid-way between top and bottom of apparatus 300.
• Pallet 320 can translate (as indicated by the double headed arrow) forward and/or backward through system 300.
• the substrate may be moved forward and backward in front of a lithium target, 330, making multiple passes in order to achieve a desired lithiation.
• Pallet 320 and substrate 325 are in a substantially vertical orientation.
• a substantially vertical orientation is not limiting, but it may help to prevent defects because particulate matter that may be generated, e.g., from agglomeration of atoms from sputtering, will tend to succumb to gravity and therefore not deposit on substrate 325.
• a vertical orientation of the substrate as it traverses the stations of the integrated deposition system enables coating of thinner glass substrates since there are less concerns over sag that occurs with thicker hot glass.
• Target 330 in this case a cylindrical target, is oriented substantially parallel to and in front of the substrate surface where deposition is to take place (for convenience, other sputter means are not depicted here).
• Substrate 325 can translate past target 330 during deposition and/or target 330 can move in front of substrate 325.
• the movement path of target 330 is not limited to translation along the path of substrate 325.
• Target 330 may rotate along an axis through its length, translate along the path of the substrate (forward and/or backward), translate along a path perpendicular to the path of the substrate, move in a circular path in a plane parallel to substrate 325, etc.
• Target 330 need not be cylindrical, it can be planar or any shape necessary for deposition of the desired layer with the desired properties. Also, there may be more than one target in each deposition station and/or targets may move from station to station depending on the desired process.
• Integrated deposition system 300 also has various vacuum pumps, gas inlets, pressure sensors and the like that establish and maintain a controlled ambient environment within the system. These components are not shown, but rather would be appreciated by one of ordinary skill in the art.
• System 300 is controlled, e.g., via a computer system or other controller, represented in Figure 3B by an LCD and keyboard, 335.
• a computer system or other controller represented in Figure 3B by an LCD and keyboard, 335.
• One of ordinary skill in the art would appreciate that embodiments herein may employ various processes involving data stored in or transferred through one or more computer systems. Embodiments also relate to the apparatus, such computers and microcontrollers, for performing these operations. These apparatus and processes may be employed to deposit electrochromic materials of methods herein and apparatus designed to implement them.
• the control apparatus may be specially constructed for the required purposes, or it may be a general-purpose computer selectively activated or reconfigured by a computer program and/or data structure stored in the computer.
• the processes presented herein are not inherently related to any particular computer or other apparatus.
• various general-purpose machines may be used with programs written in accordance with the teachings herein, or it may be more convenient to construct a more specialized apparatus to perform and/or control the required method and processes.
• the various stations of an integrated deposition system may be modular, but once connected, form a continuous system where a controlled ambient environment is established and maintained in order to process substrates at the various stations within the system.
• Figure 3C depicts integrated deposition system 300a, which is like system 300, but in this example each of the stations is modular, specifically, an EC layer station 304a, an IC layer station 304b and a CE layer station 306c. In a similar embodiment, the IC layer station 304b is omitted. Modular form is not necessary, but it is convenient, because depending on the need, an integrated deposition system can be assembled according to custom needs and emerging process advancements.
• Figure 3D depicts an integrated deposition system, 300b, with two lithium deposition stations, 307a and 307b.
• System 300b is, e.g., equipped to carry out methods herein as described above, such as the dual lithiation method.
• System 300b could also be used to carry out a single lithiation method, for example by only utilizing lithium station 307b during processing of the substrate.
• system 300c has only one lithium deposition station, 307.
• Systems 300b and 300c also have one or more TCO layer station, 308, for depositing the TCO layer on the EC stack.
• TCO refers to transparent conductive oxide.
• conductive layers 104 and 114 may be TCO layers. While Figures 3D and 3E show only a single TCO layer station 308, it is understood that in cases where the first conductive layer is deposited on the substrate (e.g., rather than the substrate being provided with the first conductive layer thereon), an additional TCO station may be provided, for example between the entry load lock 302 and the EC layer station 306a (or between the entry load lock 302 and the CE layer station 306c in cases where the counter electrode layer is deposited prior to the electrochromic layer).
• additional stations can be added to the integrated deposition system, e.g., stations for cleaning processes, laser scribes, capping layers, etc.
• the sputtering process for forming the layers may utilize one or more sputter targets.
• the target may include all of the metals that are desired in the deposited layer (e.g., nickel and tungsten for a NiWO layer; nickel, tungsten, and tantalum for a NiWTaO layer; nickel tungsten, and niobium for a NiWNbO layer; nickel, tungsten and tin for a NiWSnO layer; tungsten and molybdenum for a WMoO layer, etc.).
• the target may be in the form of a metal alloy, intermetallic mixture, a metal oxide material, or a combination thereof.
• the composition of the target reflects the metal ratios described herein, using the variable x, without oxygen (y is 0).
• the targets may have the same composition or different compositions (e.g., with different metals or combinations of metals on each target).
• the sputter target may include a grid or other overlapping shapes where different portions of the grid include the different relevant materials (e.g., certain portions of the grid may include elemental metals or alloys of metals that together form the desired composition).
• each target may include one or both of tungsten and molybdenum.
• the first target includes tungsten and the second target includes molybdenum.
• two targets are used to form a nickel tungsten tantalum oxide counter electrode.
• the first target may include nickel and the second target may include tungsten and tantalum; or the first target may include nickel and tungsten and the second target may include tantalum; or the first target may include nickel and tantalum and the second target may include tungsten.
• Similar examples are possible with other materials, including but not limited to nickel tungsten tin oxide and nickel tungsten niobium oxide, each of which may be used as a counter electrode material in certain embodiments.
• the metals may be provided separately (e.g., as elemental metals provided together in a grid or other pattern), as alloys, or a combination thereof.
• a sputter target may include an alloy of the relevant materials (e.g., tungsten and molybdenum for forming a tungsten molybdenum oxide layer; two or more of nickel, tungsten, and tantalum for forming a nickel tungsten tantalum oxide layer; two or more of nickel, tungsten, and tin for forming a nickel tungsten tin oxide layer; or two or more of nickel, tungsten, and niobium for forming a nickel tungsten niobium oxide layer).
• an alloy of the relevant materials e.g., tungsten and molybdenum for forming a tungsten molybdenum oxide layer; two or more of nickel, tungsten, and tantalum for forming a nickel tungsten tantalum oxide layer; two or more of nickel, tungsten, and tin for forming a nickel tungsten tin oxide layer; or two or more of nickel, tungsten, and niobium for
• each sputter target may include at least one of the relevant materials (e.g., elemental and/or alloy forms of the relevant metals, any of which can be provided in oxide form).
• the sputter targets may overlap in some cases.
• the sputter targets may also rotate in some embodiments.
• the electrochromic and counter electrode layers are each typically an oxide material. Oxygen may be provided as a part of the sputter target and/or sputter gas.
• the sputter targets are substantially pure metals or alloys (e.g., lacking oxygen), and sputtering is done in the presence of oxygen to form the oxide.
• multiple targets are used so as to obviate the need for inappropriately high power (or other inappropriate adjustment to desired process conditions) to increase deposition rate.
• Table 2 provides various examples of sets of targets that may be used together to form tungsten molybdenum oxide according to certain embodiments. Any of these materials may be provided in oxide form. Where two metals are provided together, they may be provided as elemental metals (e.g., in a grid or other pattern), or they may be provided as an alloy. Table 2
• Table 3 provides various examples of sets of targets that may be used together to form nickel tungsten tantalum oxide according to certain embodiments. Any of these materials may be provided in oxide form. Where two metals are provided together, they may be provided as elemental metals (e.g., in a grid or other pattern), or they may be provided as an alloy.
• Table 4 provides various examples of sets of targets that may be used together to form nickel tungsten niobium oxide according to certain embodiments. Any of these materials may be provided in oxide form. Where two metals are provided together, they may be provided as elemental metals (e.g., in a grid or other pattern), or they may be provided as an alloy.
• Table 5 provides various examples of sets of targets that may be used together to form nickel tungsten tin oxide according to certain embodiments. Any of these materials may be provided in oxide form. Where two metals are provided together, they may be provided as elemental metals (e.g., in a grid or other pattern), or they may be provided as an alloy.
• Tables 2-5 describe various examples related to formation of tungsten molybdenum oxide, nickel tungsten tantalum oxide, nickel tungsten niobium oxide, and nickel tungsten tin oxide. These are merely examples, and are not intended to be limiting. In other examples, different electrochromic and/or counter electrode materials may be used.
• the density and orientation/shape of material that sputters off of a sputter target depends on various factors including, for example, the magnetic field shape and strength, pressure, and power density used to generate the sputter plasma.
• the distance between adjacent targets, as well as the distance between each target and substrate, can also affect how the sputter plasmas will mix and how the resulting material is deposited on the substrate.
• two different types of sputter targets are provided to deposit a single layer in an electrochromic stack: (a) primary sputter targets, which sputter material onto a substrate, and (b) secondary sputter targets, which sputter material onto the primary sputter targets.
• the primary and secondary sputter targets may include any combination of metal, metal alloys, and metal oxides that achieve a desired composition in a deposited layer (including, but not limited to, any of the combinations described in Tables 2-5, with the“first target” listed in the tables corresponding to either the primary target or the secondary target).
• a primary sputter target includes tungsten and a secondary sputter target includes molybdenum.
• These sputter targets may be used to deposit an electrochromic layer comprising tungsten molybdenum oxide.
• Other combinations of elemental metals and alloys can also be used, as desired.
• the secondary sputter target may be operated at a potential that is cathodic compared to the potential of the primary sputter target (which is already cathodic).
• the targets may be operated independently. Still further, regardless of relative target potentials, neutral species ejected from the secondary target will deposit on the primary target. Neutral atoms will be part of the flux, and they will deposit on a cathodic primary target regardless of relative potentials.

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