Optoelectronic device comprising a barrier coating

Abstract

Organic optoelectronic devices comprising barrier coatings are disclosed. In particular, barrier coatings and methods and processes for depositing barrier coatings on surfaces are disclosed.

Description

[0001] This application is a divisional application of Chinese Patent Application No. "201680073928.X", filed on December 16, 2016, entitled "Barrier Coatings for Optoelectronic Devices". TECHNICAL FIELD

[0002] The following relates to barrier coatings for organic optoelectronic devices and methods for the same. In particular, the following relates to barrier coatings and methods and processes for depositing barrier coatings on surfaces. BACKGROUND

[0003] An organic light emitting diode (OLED) typically includes several layers of organic material interposed between conductive thin film electrodes, at least one of which is an electroluminescent layer. When a voltage is applied to the electrodes, holes and electrons are injected by the anode and cathode, respectively. The holes and electrons injected by the electrodes migrate through the organic layers to the electroluminescent layer. When the holes and electrons are in close proximity, they attract each other due to the Coulomb force. The holes and electrons can then recombine to form a bound state known as an exciton. The exciton can decay by a radiative recombination process in which a photon is emitted. Alternatively, the exciton can decay by a non-radiative recombination process in which no photon is emitted. It should be noted that, as used herein, internal quantum efficiency (IQE) is understood to be the proportion of all electron-hole pairs generated in a device that decay by the radiative recombination process.

[0004] The radiative recombination process can occur in the form of a fluorescent or phosphorescent process, depending on the spin state of the electron-hole pair (i.e., exciton). In particular, excitons formed from electron-hole pairs can be characterized as having a singlet spin state or a triplet spin state. Generally, the radiative decay of singlet excitons produces fluorescence, while the radiative decay of triplet excitons produces phosphorescence.

[0005] More recently, other light emission mechanisms for OLEDs have been proposed and investigated, including thermally activated delayed fluorescence (TADF). Simply stated, TADF emission results from a process whereby a triplet exciton is converted to a singlet exciton by a reverse intersystem crossing process with the aid of thermal energy, and then the singlet exciton radiatively decays.

[0006] External quantum efficiency (EQE) of an OLED device can refer to the ratio of the number of carriers provided to the OLED device relative to the number of photons emitted by the device. For example, an EQE of 100% indicates that every electron injected into the device emits one photon. It should be understood that the EQE of a device is typically significantly lower than the IQE of the device. The distinction between EQE and IQE can generally be attributed to factors such as absorption and reflection of light by various components of the device.

[0007] OLED devices can generally be classified, depending on the relative direction from which light is emitted from the device, as "bottom-emitting" or "top-emitting" devices. In a bottom-emitting device, light produced as a result of the radiative recombination process is emitted in the direction of the base substrate of the device, while in a top-emitting device, light is emitted in a direction away from the base substrate. For example, in a bottom-emitting device, the electrode proximal to the base substrate is typically made to be light-transmitting (e.g., substantially transparent or semi-transparent), and the electrode distal to the base substrate is typically made to be reflective.

[0008] Depending on the specific device structure, either the anode or the cathode can serve as the reflective electrode in a bottom-emitting device. However, in typical bottom-emitting devices, the reflective electrode is usually chosen to be the cathode. Materials commonly used to form the reflective cathode include metals such as aluminum (Al), silver (Ag), and various metal alloys.

[0009] As various parts of an OLED device are susceptible to degradation upon exposure to reactive species such as oxygen and moisture present in air, they are typically encapsulated to inhibit contact of these reactive species with the device. For example, an OLED device can be encapsulated using a combination of thin film encapsulation (TFE), barrier films, and barrier adhesives, or combinations thereof.

[0010] However, encapsulation of OLED devices remains a challenge for a number of reasons, such as due to the relatively high permeability of materials used for encapsulation, and / or the difficulties associated with forming and maintaining a hermetic seal between the encapsulation material and the surface of the OLED device. In particular for flexible OLED devices, many encapsulation materials or barrier solutions do not have suitable mechanical properties to allow the encapsulated OLED device to remain flexible while providing sufficient barrier properties. For example, some encapsulation materials comprise brittle and / or inelastic materials that crack or deform upon bending, thereby rendering the OLED device unusable. It is also known that some materials used to form barrier layers and barrier adhesives exhibit a relatively high water vapor transmission rate (WVTR) and thus can not be desirable for use in devices that require high environmental stability. Although there also exist barrier films that exhibit a relatively low WVTR of less than 10 -6 g / m 2 ·day, such films are often expensive.

[0011] In addition to the above, many OLED encapsulation schemes or processes require additional equipment, such as deposition chambers, coaters, and / or laminators, for performing the encapsulation of the device. Furthermore, these processes often require the transfer of the unencapsulated OLED device to an encapsulation apparatus after deposition of the top electrode (e.g., cathode) to complete the fabrication of the OLED device. In some cases, the unencapsulated OLED device can be exposed to air or other reactive gases during the transfer or during the encapsulation stage, which can even result in degradation and / or contamination of the device prior to encapsulation of the device. SUMMARY

[0012] In one aspect of the application, an optoelectronic device is provided, comprising a first electrode; a second electrode; an organic layer disposed between the first electrode and the second electrode; and a barrier coating disposed on the second electrode, the barrier coating comprising: two or more first portions arranged in a layer, each of the first portions comprising a fullerene; and one or more second portions, wherein the second portions are arranged in a layer alternating with the two or more first portions, the second portions comprising a metal.

[0013] In another aspect, the average density of the first portions of the barrier coating is greater than the average density of the second portions.

[0014] In yet another aspect, the compactness of each of the first portions of the barrier coating is greater than the compactness of the second portions.

[0015] In yet another aspect, the average particle size of each of the first portions of the barrier coating is less than the average particle size of the second portions.

[0016] In one embodiment, the first portions and the second portions of the barrier coating are integrally formed with each other.

[0017] In another embodiment, the fullerene comprises at least one of C 60 , C 70 , C 76 , C 84 , single-walled carbon nanotubes, and multi-walled carbon nanotubes. BRIEF DESCRIPTION OF DRAWINGS

[0018] Embodiments will be described, by way of example only, with reference to the drawings, in which:

[0019] Figure 1 is a diagram illustrating a portion of a barrier coating disposed on a substrate according to one embodiment;

[0020] Figure 2 is a diagram illustrating an optoelectronic device comprising a barrier coating according to one embodiment;

[0021] Figures 3A to 3H is a diagram illustrating an electrode disposed beneath a barrier coating according to various embodiments;

[0022] Figure 4A and Figure 4B is a diagram illustrating a method for depositing an electrode according to one embodiment;

[0023] Figure 5 is a diagram illustrating a method for depositing an electrode according to another embodiment;

[0024] Figures 6A to 6D FIG. 1 is a diagram illustrating a first portion of a barrier coating according to various embodiments;

[0025] Figure 7 FIG. 2 is a diagram illustrating a method for depositing a first portion of a barrier coating according to one embodiment;

[0026] Figure 8 FIG. 3 is a diagram illustrating a second portion of a barrier coating according to one embodiment;

[0027] Figure 9 FIG. 4 is a diagram illustrating a method for depositing a second portion of a barrier coating according to one embodiment;

[0028] Figure 10 FIG. 5 is a diagram illustrating a barrier coating according to one embodiment;

[0029] Figure 11 FIG. 6 is a diagram of an active matrix OLED (AMOLED) including a barrier coating according to one embodiment;

[0030] Figure 12 FIG. 7 is a diagram of an AMOLED including a barrier coating according to another embodiment;

[0031] Figure 13 FIG. 8 is a diagram of an optoelectronic device including a barrier coating having multiple barrier coating portions according to one embodiment;

[0032] Figure 14 FIG. 9 is a diagram of an optoelectronic device including a barrier coating having multiple barrier coating portions according to another embodiment;

[0033] Figure 15A FIG. 10 is a diagram of a barrier coating according to one embodiment;

[0034] Figure 15B FIG. 11 is a diagram of a barrier coating integrally formed with an electrode according to one embodiment;

[0035] Figure 15C FIG. 12 is a diagram of a barrier coating integrally formed with an electrode according to another embodiment;

[0036] Figure 15D FIG. 13 is a diagram of a barrier coating integrally formed with an electrode according to yet another embodiment;

[0037] Figure 16 FIG. 14 is a diagram of a non-emissive region of a sample of Example A at different times during an aging process;

[0038] Figure 17 FIG. 15 is a diagram of a non-emissive region of a sample of Example B at different times during an aging process;

[0039] Figure 18 is a plot of non-emissive area of a sample of Example C at different times during the aging process;

[0040] Figure 19 is a plot of non-emissive area of a sample of Example D at different times during the aging process;

[0041] Figure 20 is a plot of non-emissive area of a sample of Example E at different times during the aging process;

[0042] Figure 21 is a microscope photograph of a sample of Example F using a scanning electron microscope (SEM);

[0043] Figure 22 is a SEM micrograph of another sample of Example F;

[0044] Figure 23 is a SEM micrograph of yet another sample of Example F;

[0045] Figure 24 is a SEM micrograph of yet another sample of Example F; and

[0046] Figure 25 is a SEM micrograph of yet another sample of Example F. DETAILED DESCRIPTION

[0047] It should be understood that, for clarity's sake, reference numbers can be repeated in the drawings in order to represent corresponding or similar elements throughout the various figures. Moreover, numerous specific details are set forth in order to provide a thorough understanding of the example implementations described herein. However, it will be apparent to one ordinarily skilled in the art that the example implementations described herein can be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the example implementations described herein.

[0048] In one aspect, an optoelectronic device is provided. The optoelectronic device includes a coating for inhibiting the passage of moisture and / or gases (e.g., air and oxygen) therethrough. In aspects and embodiments, such a coating can be referred to herein as a barrier coating. The barrier coating can be disposed on an electrode, such as a cathode, of the optoelectronic device. The barrier coating includes a first portion and a second portion. The first portion comprises a fullerene and the second portion comprises a metal. In some cases, the second portion can comprise a mixture of a metal and a fullerene.

[0049] As used herein, the term "barrier coating" will be understood to refer to a coating that generally inhibits the passage of reactive species such as oxygen, water, and / or other gases therethrough. Passage of reactive species through a barrier coating can be inhibited by a number of mechanisms. Examples of these mechanisms include, for example, creating a tortuous path within the barrier coating that results in relatively low permeability, and by having the barrier coating portion act as a getter and / or desiccant to react or absorb the reactive species.

[0050] As used herein, the term "integrally formed" will be generally understood to refer to portions of a coating being formed as a single continuous structure as opposed to discrete layers or coatings. In some cases, this can include mixing the material of one portion with the material of an adjacent portion at the interface between layers such that the layers of the different portions are not separate and have a continuous structure. In some cases, there can be a gradual transition as one portion extends into the next portion such that the individual layers do not exhibit a distinct beginning or end.

[0051] Figure 1 An optoelectronic device 201 is shown in accordance with one embodiment, in which a barrier coating 215 is disposed over an electrode 210 formed on a substrate 200. In the illustrated embodiment, the barrier coating 215 includes a first portion 220 and a second portion 230 disposed on the first portion 220.

[0052] In some embodiments, the electrode 210 comprises a metal. For example, the metal can be a metal element, such as an alkali metal, an alkaline earth metal, a lanthanide, a transition metal, a post-transition metal, or any combination thereof. The metal can be an alloy. For example, the electrode 210 can comprise magnesium (Mg), zinc (Zn), aluminum (Al), ytterbium (Yb), silver (Ag), or any combination thereof, including alloys. For example, the alloy can be a Mg:Ag alloy having a composition of about 1 : 10 to 10: 1 by volume or by atomic composition ratio, or a Mg:Yb alloy having a composition of about 1 : 10 to 10: 1 by volume or by atomic composition ratio. In other embodiments, the electrode 210 can comprise other conductive materials. Examples of these materials include, for example, conductive polymers, nanowires, graphene, carbon nanotubes, and oxides, such as indium tin oxide (ITO).

[0053] The electrode 210 can be, for example, a cathode of the optoelectronic device 201. Thus, the electrode 210 is electrically conductive.

[0054] The first portion 220 of the barrier coating 215 can comprise fullerene. In some embodiments, the first portion 220 can comprise a mixture of a metal and fullerene. For example, the metal can be magnesium (Mg), zinc (Zn), cadmium (Cd), or any combination thereof. The fullerene can include C 60 , C 70 , C 76 , C84 The first portion 220 can include a mixture of a metal and fullerenes, where the metal comprises a majority of the first portion 220. In other words, the metal comprises greater than about 50% by volume of the mixture. In some embodiments, the metal can comprise greater than about 60%, greater than about 70%, greater than about 75%, greater than about 80%, greater than about 85%, greater than about 90%, or greater than about 95% of the mixture. In particular, as will be further explained below, it has been found that it is particularly advantageous to provide a first portion 220 including a mixture of a metal and fullerenes, where the fullerenes comprise about 1% to 25%, about 1% to 20%, about 1% to 15%, about 2% to 15%, about 5% to 15%, or about 5% to 10% by volume of the mixture. For example, the fullerenes can comprise less than 1 mole%, less than 0.8 mole%, less than 0.6 mole%, less than 0.5 mole%, less than 0.3 mole%, less than 0.1 mole%, or less than 0.08 mole% of the mixture. The metal can comprise the remainder of the mixture. In some embodiments, the metal can be pure magnesium or substantially pure magnesium, and the fullerenes can be Buckminsterfullerenes (C 60

[0055] In some embodiments, the first portion 220 can consist essentially of fullerenes. In other words, in these embodiments, the first portion 220 can include fullerenes and a small or trace amount of other substances, the presence of which does not materially affect the mechanical, electrical, and / or optical properties of the first portion 220 formed essentially of fullerenes. For example, the small or trace amount of other substances includes impurities that can be present in the fullerenes or in the reaction chamber. For example, the concentration of these substances in the first portion 220 can be less than about 0.1% by volume, less than about 0.05% by volume, less than about 0.01% by volume, less than about 0.001% by volume, or less than about 0.0001% by volume.

[0056] As used herein, the term "crystalline" should be understood to mean that the material generally exhibits long-range order or long-range structure. For example, the crystallinity of a crystalline material can be greater than about 50%, greater than about 60%, greater than about 70%, greater than about 75%, greater than about 80%, greater than about 85%, greater than about 90%, or greater than about 95%. The crystallinity of a material can be determined using various techniques, such as X-ray crystallography and differential scanning calorimetry (DSC).

[0057] The second portion 230 can include a metal. For example, the metal can be magnesium (Mg), zinc (Zn), cadmium (Cd), or any combination thereof. In some embodiments, the metal used in the second portion 230 can be the same as the metal used in the first portion 220.​

[0058] The second portion 230 can include a getter and / or a hygroscopic substance (i.e., a desiccant). For example, the second portion 230 can include pure magnesium or substantially pure magnesium, which is both a getter and a desiccant. As will be appreciated by those skilled in the art, a getter is generally a substance provided on a product or device to improve the "shelf life" of the product or device. The getter generally removes, passivates, controls, or otherwise inhibits the negative effects of undesirable substances on the performance of the device. According to one embodiment, the second portion 230 is integrally formed with the first portion 220 by depositing a relatively thick coating including magnesium on the first portion 220. The getter can react with, or otherwise passivate, oxygen and / or water vapor present in the device packaging environment to produce magnesium oxide and / or magnesium hydroxide, and thereby remove these molecules from the device packaging environment. The coating portion acting as a getter can have a reduced concentration, or zero concentration, of fullerenes. It can be particularly advantageous to provide a getter in an OLED device because OLED devices contain an emissive layer that can be quenched in the presence of oxygen. By providing a getter, the concentration of oxygen within the packaging environment of the OLED device can be relatively reduced, thereby slowing the degradation of the emissive layer.

[0059] In some embodiments, the electrode 210 can also include fullerenes. In particular, the electrode 210 can include a mixture of fullerenes and a metal. In these embodiments, the fullerenes can constitute a relatively small portion of the mixture. For example, the fullerenes can constitute less than about 15%, less than about 10%, less than about 8%, less than about 5%, less than about 3%, less than about 2%, or less than about 1%, by volume, of the mixture. The metal can constitute the remainder of the mixture. In some applications, it can be particularly advantageous for the electrode 210 to include, for example, less than 5% or less than 2% by volume of fullerenes, with the metal constituting the remainder of the electrode 210. For example, in applications where it is advantageous for the electrode 210 to have a relatively high reflectivity and / or a relatively low absorptivity, it can be preferable for the electrode 210 to contain a relatively small amount of fullerenes because fullerenes generally absorb light in the visible portion of the electromagnetic spectrum. Having a relatively high concentration of fullerenes in the electrode 210 can, at least in some cases, disadvantageously result in a decrease in the reflectivity and an increase in the absorptivity of light incident on the electrode 210. However, by having a relatively low concentration of fullerenes in the electrode 210, these adverse optical properties associated with fullerenes can be reduced.

[0060] In one embodiment, the electrode 210 includes a mixture of fullerenes and pure magnesium or substantially pure magnesium. In another embodiment, the fullerenes can constitute less than about 2% by volume of the mixture, with the pure magnesium or substantially pure magnesium constituting the remainder of the mixture.

[0061] In some embodiments, the electrode 210 and the first portion 220 comprise the same metal. In some embodiments, the first portion 220 and the second portion 230 comprise the same metal. In another embodiment, the electrode 210, the first portion 220, and the second portion 230 comprise the same metal. For example, the electrode 210, the first portion 220, and the second portion 230 may comprise magnesium.

[0062] In some embodiments, the barrier coating 215, including the first portion 220 and the second portion 230, is formed integrally or continuously. For example, the first portion 220 and the second portion 230 can be formed by continuously subjecting a target surface (e.g., the surface of the electrode 210) to a stream of evaporated metal to deposit the metal on the surface of the electrode 210. The metal can be, for example, magnesium. The surface of the electrode 210 can also be subjected to a stream of evaporated fullerenes to deposit fullerenes at various stages of forming the barrier coating 215. For example, as will be described, fullerenes can be deposited at stages corresponding to the formation of the first portion 220 and, optionally, the second portion 230. During the formation or deposition of the barrier coating 215, the metal deposition rate and / or the fullerene deposition rate can be varied to produce a coating having a desired composition and / or properties.

[0063] In some embodiments, the barrier coating 215 may have one or more additional portions. For example, the one or more additional portions may be disposed between the first portion 220 and the second portion 230, or disposed on the second portion 230. The one or more additional portions may comprise an organic material, an inorganic material, and / or a combination thereof. For example, the one or more additional portions may comprise a polymer, a small molecule organic compound, and / or an oxide, such as silicon dioxide. In some embodiments, the barrier coating 215 may include multiple first portions 220. The barrier coating 215 may also include multiple second portions 230. In these embodiments, the first portions 220 and the second portions 230 may be arranged alternately in layers or stacked on top of each other. For example, the second portions 230 may be disposed between adjacent first portions 220 such that adjacent first portions 220 are separated by the second portions 230.

[0064] In some embodiments, the barrier coating 215 can be disposed on an optoelectronic device or a portion thereof. An optoelectronic device is generally any device that converts an electrical signal into photons or converts photons into electrical signals. Thus, as used herein, an organic optoelectronic device will be understood as any optoelectronic device in which the active layer of the device is primarily formed of an organic material, more specifically, an organic semiconductor material. Examples of organic optoelectronic devices include, but are not limited to, organic light emitting diode (OLED) devices and organic photovoltaic (OPV) devices. In another example, the optoelectronic device can be an electroluminescent quantum dot light emitting device in which the electroluminescent layer of the device includes quantum dots.

[0065] In one embodiment, the organic optoelectronic device is an organic light emitting diode, wherein the organic semiconductor layer comprises an electroluminescent layer. In other embodiments, the organic semiconductor layer may comprise additional layers, such as an electron injection layer, an electron transport layer, a hole transport layer, and / or a hole injection layer.

[0066] In one embodiment, the barrier coating 215 is disposed on the surface of the organic coating or layer of the OLED device. Thus, in such an embodiment, the substrate 200 may include one or more organic coatings or layers. For example, the barrier coating 215 may be disposed on the cathode 210, which is disposed on a charge injection layer or charge transport layer (e.g., an electron injection layer or an electron transport layer) of the OLED device. In some embodiments, the barrier coating 215 may form at least a portion of an electrode, such as a cathode, of the OLED device. The substrate 200 may also include an electrode (e.g., a counter electrode to the electrode 210). The substrate 200 may also include a base substrate on which the electrodes and one or more organic coatings or layers are deposited.

[0067] In some embodiments, the thickness of the first portion 220 may be less than the thickness of the second portion 230. 60 is relatively expensive, so reducing the thickness of the fullerene-containing coating portion may be advantageous. Additionally or alternatively, the fullerene concentration in portions of the coating may be reduced to provide a more cost-effective barrier coating.

[0068] For example, the thickness of electrode 210 can be greater than about 5 nm, greater than about 10 nm, greater than about 25 nm, greater than about 50 nm, greater than about 75 nm, greater than about 100 nm, greater than about 150 nm, or greater than about 200 nm. For example, the thickness of electrode 210 can be about 20 nm to 500 nm, about 20 nm to 300 nm, or about 50 nm to 250 nm.

[0069] For example, the thickness of the first portion 220 can be greater than about 1 nm, greater than about 10 nm, greater than about 20 nm, or greater than about 50 nm. However, in some cases, it may be particularly advantageous to provide a relatively thick coating of the first portion 220. For example, the thickness of the first portion 220 can be greater than about 80 nm, greater than about 100 nm, greater than about 150 nm, or greater than about 200 nm. For example, the thickness of the first portion 220 can be between about 50 nm and 500 nm, between about 50 nm and 250 nm, between about 80 nm and 200 nm, or between about 100 nm and 200 nm.

[0070] For example, the second portion 230 can have a thickness greater than about 50 nm, greater than about 80 nm, or greater than about 100 nm. However, it can be particularly advantageous to provide a relatively thick second portion 230 of the coating in at least some cases where the second portion 230 acts as a getter or desiccant. By providing a relatively thick getter or desiccant, penetration of gases such as air or water vapor can be inhibited to a greater extent. For example, the second portion 230 can have a thickness greater than about 120 nm, greater than about 150 nm, greater than about 200 nm, or greater than about 250 nm. For example, the second portion 230 can have a thickness of about 50 nm to 500 nm, about 100 nm to 400 nm, about 100 nm to 300 nm, or about 200 nm to 300 nm.

[0071] The total thickness of the barrier coating 215 can be, for example, greater than about 50 nm. However, it can be advantageous to provide a relatively thick barrier coating 215 to obtain greater reflectivity and conductivity, particularly in cases where the barrier coating 215 is disposed as part of a reflective electrode (e.g., a cathode) of an optoelectronic device. For example, the thickness of the barrier coating 215 can be greater than about 80 nm, greater than about 100 nm, greater than about 150 nm, greater than about 200 nm, greater than about 300 nm, greater than about 500 nm, greater than about 700 nm, or greater than about 1000 nm. Particularly in cases where the barrier coating 215 is disposed in a flexible device (e.g., a flexible OLED), it can be advantageous for the barrier coating 215 to have a thickness sufficient to obtain desired electrical and optical properties, while being thin enough to allow the device to remain flexible. Thick coatings containing metals are generally not suitable for use in many flexible device applications due to the mechanical properties of these coatings. Thus, in some embodiments, the thickness of the barrier coating 215 can be about 100 nm to 5000 nm, about 100 nm to 2500 nm, about 100 nm to 2000 nm, about 100 nm to 1500 nm, about 100 nm to 1000 nm, about 100 nm to 800 nm, about 100 nm to 600 nm, about 100 nm to 500 nm, about 150 nm to 500 nm, about 200 nm to 500 nm, or about 300 nm to 500 nm.

[0072] However, it should be understood that the thickness of the first portion 220 and the second portion 230 can vary depending on the application and the materials used to form the coating, and thus the thickness of the barrier coating and its portions can not be limited to any of the specific ranges specifically recited herein.

[0073] In Figure 1In some embodiments, the electrode 210, the first portion 220, and the second portion 230 are shown as being disposed adjacent to or in close proximity to each other. Specifically, the first portion 220 is shown as being disposed in close proximity to the electrode 210 and the second portion 230, such that the first portion 220 is in direct contact with the electrode 210 and the second portion 230. In particular, in these embodiments, the electrode 210, the first portion 220, and the second portion 230 can be in electrical contact with each other. However, in other embodiments, additional layers or coatings can be disposed between the electrode 210 and the first portion 220, and / or between the first portion 220 and the second portion 230.

[0074] Figure 2 1 is an OLED device 101 according to one embodiment, wherein the device includes a barrier coating 215. Specifically, the OLED device 101 includes a base substrate 100, a first electrode 110, a plurality of organic layers 125, a second electrode 210, and a barrier coating 215. For example, the first electrode 110 can be an anode, and the second electrode 210 can be a cathode. In some embodiments, the barrier coating 215 can also serve as part of the cathode.

[0075] exist Figure 2 The multiple organic layers 125 in the embodiment include a hole injection layer 120, a hole transport layer 130, an electroluminescent layer 140, an electron transport layer 150, and an electron injection layer 160. The hole injection layer 120 can be formed using a hole injection material that generally promotes the injection of holes from the anode 110. The hole transport layer 130 can be formed using a hole transport material that is generally a material that exhibits high hole mobility. The electroluminescent layer 140 can be formed, for example, by doping a host material with an emitter material. For example, the emitter material can be a fluorescent emitter, a phosphorescent emitter, or a TADF emitter. A variety of emitter materials can also be doped into the host material to form the electroluminescent layer 140. The electron transport layer 150 can be formed using an electron transport material that generally exhibits high electron mobility. The electron injection layer 160 can be formed using an electron injection material that generally promotes the injection of electrons from the cathode.

[0076] It should be understood that the structure of the device 101 can be varied by omitting or combining one or more layers. In particular, one or more of the hole injection layer 120, the hole transport layer 130, the electron transport layer 150, and the electron injection layer 160 can be omitted from the device structure. One or more additional layers can also be present in the device structure. These additional layers include, for example, hole blocking layers, electron blocking layers, and additional charge transport and / or charge injection layers. Each layer can also include a number of sub-layers, and each layer and / or each sub-layer can include a plurality of mixtures and composition gradients. It should also be understood that the device 101 can include one or more layers containing inorganic and / or organometallic materials, and is not limited to devices constructed solely of organic materials. For example, the device 101 can include quantum dots.

[0077] It should also be understood that the device 101 can be formed on various types of base substrates. For example, the base substrate 100 can be a flexible or rigid substrate. The base substrate 100 can include, for example, silicon, glass, metal, a polymer (e.g., polyimide), sapphire, or other materials suitable for use as a base substrate. In the case of an active matrix organic light emitting diode (AMOLED) display device, the base substrate 100 can also include a plurality of thin film transistors (TFTs).

[0078] Figure 2 The device 101 illustrated in FIG. 1 can be a bottom-emitting OLED device, where the device is configured to emit light in the direction of the base substrate 100. Thus, in such embodiments, the first electrode 110 (e.g., anode) can be substantially transparent or light transmissive, and the second electrode 210 can be substantially reflective in the visible wavelength portion of the electromagnetic spectrum. In such embodiments, a portion of the barrier coating 215 can also be substantially reflective in the visible wavelength portion of the electromagnetic spectrum. In some embodiments, the second electrode 210 and the first portion 220 can together form a cathode of the device 101. In yet another embodiment, the second electrode 210, the first portion 220, and the second portion 230 can collectively form a cathode of the device 101. Thus, at least a portion of the barrier coating 215 (e.g., the first portion 220) can be electrically conductive. In one embodiment, the first portion 220 and the second portion 230 are electrically conductive. In another embodiment, the second electrode 210, the first portion 220, and the second portion 230 can be electrically connected to one another to allow current to pass through the barrier coating 215 into the organic layer 125.

[0079] As used herein, the term "reflective" is generally understood to mean that light incident on a coating or layer is reflected. For example, a reflective coating or layer can cause greater than 40%, greater than 50%, greater than 60%, greater than 70%, greater than 75%, greater than 80%, greater than 90%, or greater than 95% of light incident thereon to be reflected.

[0080] In one aspect, a method for forming a barrier coating is provided. The method includes (i) depositing a conductive material to form a conductive coating on a surface of a substrate, (ii) co-depositing fullerene and the conductive material to form a first portion on the conductive coating, and (iii) depositing the conductive material to form a second portion on the first coating.

[0081] Figures 3A to 3H Various embodiments of forming an electrode 210 on a surface 204 of a substrate 200 are shown.

[0082] In Figure 3A In some embodiments, the conductive coating or electrode 210 is deposited on the surface 204 of the substrate 200 such that the electrode 210 directly contacts the surface 204. In some embodiments, the electrode 210 comprises a metal. For example, the metal can be a metal element, such as an alkali metal, an alkaline earth metal, a lanthanide, a transition metal, a post-transition metal, or any combination thereof. The metal can be an alloy. For example, the electrode 210 can comprise magnesium (Mg), zinc (Zn), aluminum (Al), ytterbium (Yb), silver (Ag), or any combination thereof, including alloys. For example, the alloy can be a Mg:Ag alloy having a composition of about 1 : 10 to 10: 1 by volume or by atomic composition ratio, or a Mg:Yb alloy having a composition of about 1 : 10 to 10: 1 by volume or by atomic composition ratio.

[0083] While various materials can be used to form the electrode 210, it can be advantageous to use magnesium to form the electrode 210. For example, magnesium has a lower work function of 3.6 eV when compared to aluminum, which is commonly used to form cathodes of OLED devices. Magnesium can also be thermally deposited at much lower deposition temperatures, such as at a deposition temperature of 400 °C or less, which is significantly lower than the deposition temperature of aluminum, and thus is more cost effective and easier to process.

[0084] However, it has been previously reported that substantially pure magnesium cannot be used as an effective cathode for organic optoelectronic devices because of its poor adhesion to organic materials and its low environmental stability. For example, U.S. Pub. No. 2012 / 0313099 further describes the poor adhesion of magnesium to organic surfaces. In addition, magnesium is prone to oxidation, and thus it is difficult to manufacture and operate devices having a magnesium cathode in an oxygen and / or humid environment because the conductivity of the cathode rapidly deteriorates as the magnesium oxidizes. While it is possible to deposit magnesium on the surface of various inorganic surfaces, such as glass and silicon, the adhesion coefficient of magnesium on these surfaces is typically low. Thus, the deposition rate of magnesium on these surfaces is relatively low, and the process is not cost effective.

[0085] Accordingly, in one embodiment shown in Figure 3B In particular, inFigure 3B In embodiments, the electrode 210 includes a nucleation-promoting coating 211 disposed on the surface 204 and a metal coating 212 disposed on the nucleation-promoting coating 211. The nucleation-promoting coating 211 can include, for example, fullerenes. The metal coating 212 can include magnesium. For example, the metal coating 212 can include pure magnesium or substantially pure magnesium.

[0086] Based on prior findings and experimental observations, as will be further explained herein, the inventors hypothesize that the nucleation-promoting coating including fullerenes serves as a nucleation site for magnesium deposition. For example, in the case of using an evaporation method to deposit magnesium or a magnesium alloy on a fullerenes-treated surface, the fullerenes molecules serve as nucleation sites for initiating condensation (i.e., desublimation) of magnesium or a magnesium alloy. It is also observed in some cases that less than a monolayer of fullerenes can be provided on the treated surface to serve as a nucleation site for successful deposition of magnesium. As will be appreciated, treating the surface by depositing multiple layers of fullerenes can result in a greater number of nucleation sites.

[0087] It is to be understood, however, that the amount of fullerenes deposited on the surface can be more or less than one monolayer. For example, the surface can be treated to produce a nucleation-promoting coating by depositing less than about 0.1 monolayers, less than about 0.2 monolayers, less than about 0.3 monolayers, less than about 0.4 monolayers, less than about 0.5 monolayers, less than about 0.6 monolayers, less than about 0.7 monolayers, less than about 0.8 monolayers, less than about 0.9 monolayers, or less than about 1 monolayer of fullerenes. Further, the nucleation-promoting coating can be formed by depositing more than about 1 monolayer, more than about 10 monolayers, or more of fullerenes. As used herein, depositing 1 monolayer of fullerenes is understood to mean that the amount of fullerenes deposited on the surface is equal to the amount of fullerenes needed to cover the desired surface area with a monolayer of fullerenes molecules. Similarly, as used herein, depositing 0.1 monolayers of fullerenes is understood to mean that the amount of fullerenes deposited on the surface is equal to the amount of fullerenes needed to cover 10% of the desired surface area with a monolayer of fullerenes molecules. It is to be understood that due to the stacking of fullerenes molecules, individual coverage layers can leave certain areas of the substrate uncovered by a fullerenes layer, while other areas of the substrate can have 2 or more fullerenes coverage layers.

[0088] In the embodiment shown in FIG. 1, the electrode 210 includes a nucleation-promoting coating 211 disposed on the surface 204 of the substrate 200 and a metal coating 212 disposed on the nucleation-promoting coating 211. The nucleation-promoting coating 211 can include, for example, fullerenes. The metal coating 212 can include magnesium. For example, the metal coating 212 can include pure magnesium or substantially pure magnesium. Figure 3C In the embodiment shown in FIG. 1, the electrode 210 includes a nucleation-promoting coating 211 disposed on the surface 204 of the substrate 200 and a metal coating 212 disposed on the nucleation-promoting coating 211. The nucleation-promoting coating 211 can include, for example, fullerenes. The metal coating 212 can include magnesium. For example, the metal coating 212 can include pure magnesium or substantially pure magnesium. Figure 4A and Figure 4B A process for depositing the electrode 210 according to one embodiment is further shown in FIGS. 2A-2C. As shown in FIG. 2A, a substrate 200 having a surface 204 is provided. The surface 204 can be treated to produce a nucleation-promoting coating 211 by depositing less than a monolayer of fullerenes 311 on the surface 204.Figure 4A As shown, a nucleation-promoting coating comprising sub-monolayers of fullerene 311 is deposited onto the substrate 200 by evaporating a fullerene source material (not shown) at a first source 401 and flowing the fullerene vapor onto the substrate 200. As Figure 4B As described, once the fullerene 311 is deposited, a second source 402 is used to evaporate a metal source material (not shown) and flow the evaporated metal onto the fullerene-treated surface. In this way, a conductive coating 210 can be formed Figure 3C As shown in the middle.

[0089] As described above with reference to Figure 3C The fullerene can not completely cover the surface 204 of the substrate 200, such that a majority of the surface 204 of the substrate 200 is uncovered. Alternatively, the surface 204 of the substrate 100 can be completely covered with fullerene. Once the surface 204 of the substrate 200 has been treated, a metal, such as magnesium, can be deposited by a source to form a conductive coating on the electrode 210. It is assumed that the fullerene on the surface of the substrate 200 can act as nucleation sites, which enable the magnesium to bind with the fullerene molecules and subsequently grow to form a conductive coating. It is also assumed that as the magnesium is deposited by the metal source, the spaces or voids between the fullerene molecules on the treated surface are gradually filled with magnesium.

[0090] Figure 3D Another embodiment is shown in which the electrode 210 comprises fullerene 311 dispersed in a metal 322, such as magnesium. For example, such a coating can be formed by co-depositing the fullerene 311 and the metal 322 simultaneously onto the surface 204 of the substrate 200. In Figure 5 A process for depositing the electrode 210 according to one embodiment is further shown in the middle. In Figure 5 In the middle, the fullerene 311 is deposited by evaporating a fullerene source material (not shown) using a first source 401 to flow fullerene vapor onto the substrate 200, while a metal source material (not shown) is evaporated using a second source 402 to flow evaporated metal onto the substrate 200. Alternatively, it can be formed by evaporating a co-source material comprising a mixture of fullerene and metal and subjecting the substrate 200 to a flow of fullerene and metal evaporation. For example, such a process can be performed using a single evaporation source. It is understood that in Figure 3D In embodiments of the present application, although the fullerene is dispersed throughout the electrode 210, at least some fullerene can be provided at the interface between the electrode 210 and the substrate 200 as a nucleation-promoting coating.

[0091] Figure 3EYet another embodiment is shown in which a nucleation promoting coating having sub-monolayers is within the substrate 200. For example, the substrate can include an electron injection layer on which the electrode 210 is deposited. In this case, the fullerenes 311 can be "doped" or disposed within the substrate (e.g., electron injection layer), particularly at the interface between the substrate 200 and the electrode 210, to provide a fullerenes-treated surface on which the metal 322 can be deposited.

[0092] Figure 3F Yet another embodiment is shown in which the fullerenes 311 are dispersed within at least a portion of the substrate 200. For example, the substrate can include an electron injection layer on which the electrode 210 is deposited. In this case, the fullerenes 311 can be doped or dispersed throughout the substrate (e.g., electron injection layer) to provide a fullerenes-treated surface on which the metal 322 can be deposited. In particular, the fullerenes 311 can be provided at the interface between the substrate 200 and the electrode 210.

[0093] Figure 3G is an embodiment in which the fullerenes 311 are dispersed within at least a portion of the substrate 200, and in addition, the surface 204 of the substrate 200 has been treated by depositing a sub-monolayer of a fullerenes nucleation promoting coating thereon prior to depositing the metal 322 to form the electrode 210.

[0094] Figure 3H is another embodiment in which the fullerenes 311 are dispersed within both the substrate 200 and the electrode 210 including the metal 322. It is understood that the fullerenes can be particularly disposed at the interface between the electrode 210 and the substrate 200.

[0095] Figures 6A to 6D Various embodiments are shown for forming the first portion 220 on the electrode 210.

[0096] In Figure 6A the first portion 220 is deposited on the electrode 210. For example, the first portion 220 includes fullerenes dispersed within a metal. The metal can include magnesium. The fullerenes can be substantially uniformly or uniformly dispersed throughout the first portion 220. Alternatively, the fullerenes concentration can vary throughout the first portion 220.

[0097] In Figure 6BIn the middle, a first portion 220 is shown that includes a first region 221 and a second region 222. The first region 221 is disposed proximal to the substrate 200 and the second region 222 is disposed distal to the substrate 200. For example, the first region 221 can be deposited on the electrode 210 such that the electrode 210 is in contact with the first region 221. The first region 221 and the second region 222 can be formed continuously or integrally with one another. In the illustrated embodiment, the first region 221 and the second region 222 each include fullerene 226 and metal 228. The metal 228 can include magnesium, for example. The metal 228 can be pure magnesium or substantially pure magnesium. The first region 221 can include a higher concentration of fullerene 226 than the second region 222. For example, the fullerene 226 can be disposed at an interface between the first portion 220 and the electrode 210.

[0098] In Figure 6C In the middle, a first portion 220 is shown that includes a first region 221, a second region 222, and a third region 223. The first region 221 is disposed proximal to the substrate 200 and the third region 223 is disposed distal to the substrate 200, with the second region 222 disposed between the first region 221 and the third region 223. For example, the first region 221 can be deposited on the electrode 210 such that the electrode 210 is in contact with the first region 221. The first region 221, the second region 222, and the third region 223 can be formed continuously or integrally with one another. In the illustrated embodiment, the first region 221, the second region 222, and the third region 223 each include fullerene 226 and metal 228. The metal 228 can include magnesium, for example. The metal 228 can be pure magnesium or substantially pure magnesium. The first region 221 can include a higher concentration of fullerene 226 than the second region 222. The third region 223 can also include a higher concentration of fullerene 226 than the second region 222. The first region 221 can include a higher, lower, or substantially the same concentration of fullerene than the third region 223. The fullerene 226 can be disposed at an interface between the first portion 220 and the electrode 210, particularly where the metal 228 cannot readily be deposited on the electrode 210.

[0099] In Figure 6DIn some embodiments, the first portion 220 includes a first region 221 and a second region 222. The first region 221 is disposed proximal to the substrate 200, and the second region 222 is disposed distal to the substrate 200. For example, the first region 221 can be deposited on the electrode 210 such that the electrode 210 is in contact with the first region 221. The first region 221 and the second region 222 can be formed contiguously or integrally with one another. In the illustrated embodiment, both the first region 221 and the second region 222 include fullerene 226 and metal 228. The metal 228 can include, for example, magnesium. The metal 228 can be pure magnesium or substantially pure magnesium. The second region 222 can include a higher concentration of fullerene 226 than the first region 221. Although not explicitly shown in FIG. 6, in some embodiments, the fullerene 226 can be disposed at an interface between the first portion 220 and the electrode 210.

[0100] Figures 6A to 6D Various embodiments of the first portion 220 shown in FIG. 6 can be formed, for example, by co-deposition of the metal 228 and the fullerene 226 from separate evaporation sources. Figure 7 One embodiment of such a process is shown, in which the first portion 220 is deposited by subjecting the substrate 200 having the electrode 210 disposed thereon to evaporation streams emanating from first and second sources 401 and 402. Specifically, the first source 401 can be configured to evaporate a fullerene source material (not shown) to generate a fullerene vapor stream, and the second source 402 can be configured to evaporate a metal source material (not shown) to generate a metal vapor stream. The surface of the electrode 210 can then be subjected to the fullerene vapor stream and the metal vapor stream simultaneously or concurrently, thereby causing the first portion 220 comprising fullerene and metal to be deposited on the electrode 210. The deposition rate and / or evaporation rate of the first and second sources 401 and 402 can be adjusted or tuned to vary the concentration of fullerene in various regions or portions of the first portion 220.

[0101] Figure 8 A second portion 230 is shown deposited on the first portion 220. In some embodiments, the second portion 230 can include metal. For example, the metal can include magnesium. The metal can be pure magnesium or substantially pure magnesium. Figure 9 The second portion 230 deposited according to one embodiment is shown. In the illustrated embodiment, the second portion 230 includes a first region 231 and a second region 232. The first region 231 is disposed proximal to the substrate 200, and the second region 232 is disposed distal to the substrate 200. For example, the first region 231 can be deposited on the first portion 220 such that the first portion 220 is in contact with the first region 231. The first region 231 and the second region 232 can be formed contiguously or integrally with one another. In the illustrated embodiment, both the first region 231 and the second region 232 include metal 228. The metal 228 can include, for example, magnesium. The metal 228 can be pure magnesium or substantially pure magnesium. The second region 232 can include a higher concentration of metal 228 than the first region 231. Although not explicitly shown in FIG. 7, in some embodiments, the metal 228 can be disposed at an interface between the second portion 230 and the first portion 220. Figure 9 In embodiments of the substrate 200 having the electrode 210 and the first portion 220 deposited thereon, the substrate 200 is subjected to an evaporated metal stream from the source 402 to cause the second portion 230 to be deposited on the first portion 220. Specifically, the source 402 is configured to evaporate a source material comprising metal to generate a metal vapor stream. The surface of the first portion 220 can be subjected to the metal vapor stream to cause the second portion 230 comprising metal to be deposited thereon.

[0102] In some embodiments, the same source can be used to deposit the metal used to form the first portion 220 and the second portion 230. In these embodiments, the first portion 220 and the second portion 230 can comprise the same metal. In some embodiments, the same source can be used to deposit the metal used to form the electrode 210, the first portion 220, and the second portion 230. In these embodiments, the electrode 210, the first portion 220, and the second portion 230 can comprise the same metal. For example, the metal can comprise magnesium. The metal can be pure magnesium or substantially pure magnesium. For example, with reference to the various embodiments described above, the source 402 can be used to deposit the metal used to form the electrode 210, the first portion 220, and the second portion 230. In one embodiment, the source 402 can be configured to maintain substantially the same deposition rate and / or evaporation rate during the formation or deposition of the electrode 210, the first portion 220, and the second portion 230. In another embodiment, the source 402 can be configured to deposit the metal at a first deposition rate during the deposition of the electrode 210, at a second deposition rate during the deposition of the first portion 220, and at a third deposition rate during the deposition of the second portion 230. In some embodiments, the first deposition rate can be substantially the same as the second deposition rate, and the third deposition rate can be greater than the first deposition rate or the second deposition rate. In other embodiments, the first deposition rate and / or the second deposition rate can be less than the third deposition rate. It is assumed that, at least in some cases, a higher metal deposition rate can result in the formation of a metal coating or layer having a smaller average grain size. As will be further explained, it can be particularly advantageous to achieve a higher metal deposition rate during the formation of the first portion 220 such that the average grain size of this portion is relatively small.

[0103] It will be appreciated that additional steps can be performed after and / or before the deposition of the electrode 210, the first portion 220, and the second portion 230. For example, these additional steps can include depositing additional portions to the barrier coating 215 and / or additional barrier coatings over the barrier coating 215. The additional portions can include additional first portions and / or additional second portions. Similarly, the additional barrier coatings can include first portions and second portions, which can be defined in substantially the same manner as the first portion 220 and the second portion 230 of the barrier coating 215, respectively. For example, each portion of the additional barrier coatings can have substantially the same composition as described above with respect to the various portions of the barrier coating 215. As will be appreciated, any number of additional portions or additional barrier coatings can be provided, including, for example, 2, 3, 4, 5, or more additional portions or additional barrier coatings. These additional portions or additional barrier coatings can also be formed integrally or continuously with the barrier coating 215.

[0104] As Figure 9As shown, barrier coating 215 can be deposited on a surface of electrode 210 disposed on substrate 200. It should be appreciated that substrate 200 can comprise an organic and / or inorganic material. Thus, it should be appreciated that the surface of such a substrate can be any organic and / or inorganic surface capable of having electrode 210 deposited thereon. For further clarity, it should be appreciated that electrode 210 can be deposited on the surface using any method or process known in the art. In the case where electrode 210 comprises a fullerene deposited on surface 204 of substrate 200, the fullerene deposited on the surface can be weakly or strongly bound to the surface by intermolecular forces, intramolecular forces, and any other type of force, interaction, and / or bond. For example, the fullerene can be bound to the surface by van der Waals forces, electrostatic forces, gravitational forces, magnetic forces, dipole-dipole interactions, non-covalent interactions, and / or covalent bonds.

[0105] It should be appreciated that an organic substrate or organic surface, as used herein, should be understood to refer to a substrate or surface that comprises primarily organic material. For further clarity, an organic material is generally understood to be any material that contains carbon, wherein at least one carbon atom is covalently bound to another type of atom (e.g., hydrogen, oxygen, nitrogen, etc.). In particular, it has been found that barrier coating 215 can be deposited on surfaces of materials that are commonly used as electroluminescent layers or electron injection layers of organic light emitting diodes using the method according to the present application. In some embodiments, the surface can be an organic surface. For example, the method can comprise depositing electrode 210 on a surface of an organic layer of an organic electronic device, such as an OLED. In a more particular example, the method comprises depositing electrode 210 on a surface of an electron transport layer (ETL) or an electron injection layer (EIL). The ETL or EIL can contain a fullerene.

[0106] It should be appreciated that an inorganic substrate or surface, as used herein, should be understood to refer to a substrate that comprises or primarily comprises inorganic material. For further clarity, an inorganic material is generally understood to be any material that is not considered an organic material. Examples of inorganic materials include metals, glasses, and minerals. Surfaces that can have the method according to the present application applied thereto include surfaces of silicon-based polymers, inorganic semiconductor materials, electron injection materials, salts, metals, and metal oxides.

[0107] It should be appreciated that the substrate 200 can comprise a semiconductor material, and accordingly, the surface of such a substrate can be a semiconductor surface. A semiconductor can be described as a material having an electrical conductivity that is somewhat less than that of a conductor (e.g., a metal) but greater than that of an insulator (e.g., glass). It should be appreciated that the semiconductor material can be an organic semiconductor or an inorganic semiconductor. Some examples of organic semiconductor materials are listed above. Some examples of inorganic semiconductor materials include Group IV elemental semiconductors, Group IV compound semiconductors, Group VI elemental semiconductors, III-V semiconductors, II-VI semiconductors, I-VII semiconductors, IV-VI semiconductors, IV-VI semiconductors, V-VI semiconductors, II-V semiconductors, oxides, and other semiconductor materials.

[0108] Further, it should be appreciated that the substrate 200 can include multiple layers of organic and / or inorganic materials. For example, in the case of an organic light emitting diode (OLED), the substrate can include an electron injection layer, an electron transport layer, an electroluminescent layer, a hole transport layer, a hole injection layer, and / or an anode.

[0109] In various embodiments, the fullerene and metal used to form the barrier coating 215 have been described as being deposited using an evaporation method. As should be appreciated, an evaporation method is a type of physical vapor deposition (PVD) method in which one or more source materials are evaporated or sublimed under a vacuum environment and deposited on a target surface through condensation of the one or more evaporated source materials. A variety of different evaporation sources can be used to heat the source materials, and thus, it should be appreciated that the source materials can be heated in a variety of ways. For example, the source materials can be heated by an electric furnace filament, an electron beam, induction heating, or by resistive heating.

[0110] For example, C 60 The deposition conditions for the fullerene can be about 430 °C to 500 °C at a pressure of about 10 -7 torr, resulting in a deposition rate on the order of about 0.1 Angstroms per second. The deposition conditions for the magnesium can be about 380 °C to 430 °C in a Knudsen cell at a pressure of about 10 -7 torr, resulting in a deposition rate on the order of about 2 or greater Angstroms per second. However, it should be appreciated that other deposition conditions can be used.

[0111] For example, in the case of magnesium as the metal, magnesium can be deposited at 600 °C to achieve faster deposition rates, e.g., 10-30 nm or more per second. With reference to Table 1 below, deposition rates for various embodiments were measured using a Knudsen cell magnesium deposition source to deposit substantially pure magnesium on a fullerene-coated about 1 nm organic surface. It will be appreciated that various other factors also affect deposition rates, including but not limited to: distance between the source and the substrate, characteristics of the substrate, fullerene coverage on the substrate, type of source used, shaping of the material stream from the source. Examples of evaporation temperatures and deposition rates for substantially pure magnesium in one evaporation chamber configuration are provided in Table 1 below.

[0112] Table 1: Magnesium Deposition Rates as a Function of Temperature

[0113] Sample Temperature (°C) Rate (Angstroms / second) 1 510 10 2 525 40 3 575 140 4 600 160

[0114] It will be appreciated by those skilled in the art that the specific process conditions used are variable and can depend on the equipment used to perform the deposition. It will be appreciated that higher deposition rates are generally obtained at higher temperatures, however, the specific deposition conditions can be selected by one skilled in the art, e.g., by placing the substrate closer to the deposition source.

[0115] Both magnesium and Buckminsterfullerene (C 60 ) are known to have similar sublimation temperatures (-400 °C) under high vacuum conditions (e.g., pressures below about 10 -1 Torr). Thus, in some embodiments, both magnesium and C 60 can be deposited from a single common deposition source that deposits a mixture of Mg and C 60 source materials to form a barrier coating.

[0116] Although the evaporation method for depositing the fullerene and the metal has been described, it should be understood that various other methods can also be used to deposit these materials. For example, other physical vapor deposition (PVD) processes, such as including sputtering, can be used to deposit the fullerene and / or the metal. Other processes that can be used to deposit the fullerene and / or the metal include chemical vapor deposition (CVD) processes, printing (including ink or vapor jet printing and roll-to-roll printing), organic vapor phase deposition (OVPD), laser-induced thermal imaging (LITI) patterning, or other processes known for depositing fullerene or metal. In one embodiment, the metal is deposited by heating a magnesium source material using a resistive heater. In other embodiments, the metal source material can be loaded into a heated crucible, a heated evaporation boat, a Knudsen cell, or any other type of evaporation source. Similarly, the fullerene source material or a mixture of fullerene and metal source material can be loaded into a heated crucible, a heated evaporation boat, a Knudsen cell, or any other type of evaporation source for deposition. Various other deposition methods can be used.

[0117] In embodiments in which the metal is magnesium, the deposition source material for depositing the magnesium can be a mixture or a compound in which at least one component of the mixture or compound is not deposited on the substrate during deposition. In one example, the source material can be a Cu-Mg mixture or a Cu-Mg compound. In a more specific example, the source material for the magnesium deposition source includes magnesium and a material having a lower vapor pressure, such as Cu. In another specific example, the source material for co-depositing magnesium and fullerene includes a Cu-Mg compound mixed with fullerene, such as a Cu-Mg fullerene compound. It should be understood that other low vapor pressure materials can be provided in the source.

[0118] Referring to Figure 10 Various aspects of the barrier coating 215 will now be described. In Figure 10 In particular, in cases in which the electrode 210 and the barrier coating 215 are formed from a crystalline metal having a non-cubic crystal structure, portions of the barrier coating 215 and the electrode 210 can contain voids that allow passage of gases, such as oxygen or water vapor that can be present in air. For example, these voids can exist at grain boundaries formed between adjacent grains of the material used to form the barrier coating 215 and the electrode 210. In Figure 10 In particular, a first void 1010 is shown formed within the electrode 210, a second void 1020 is shown formed within the first portion 220, and a third void 1030 is shown formed within the second portion.

[0119] It is hypothesized that particularly in the case of relatively thick metal coatings formed using metals having a hexagonal close packed (HCP) crystal structure, dense packed coatings are not readily formed. Examples of such metals include magnesium, cadmium and zinc. In particular, it has been observed that when relatively thick magnesium coatings greater than about 1 μm are formed using substantially pure magnesium, the magnesium coatings contain relatively high densities of microscopic voids having a size greater than a few hundred nanometers. It is noted that in contrast, when metal coatings are formed using metals having a cubic crystal structure, such as aluminum or silver, significantly fewer microscopic voids are detected in these coatings as compared to the magnesium coatings.

[0120] It has now been discovered that by providing a fullerene containing portion within a barrier coating 215 containing a non-cubic crystal metal, the average size as well as the density of voids present in such portion of the coating can be significantly reduced as compared to forming a similar coating without the fullerene.

[0121] It is further hypothesized that by providing a portion containing a mixture of fullerene and metal between adjacent portions containing metal, the growth pattern of the contained metal is disrupted or interrupted. In particular, by disrupting or interrupting the growth pattern of the metal, the likelihood of the metal coating portion having a microstructure different from the underlying metal coating portion is increased.

[0122] It is hypothesized that disrupting the growth pattern of the metal can enhance the likelihood of voids provided in one portion of the coating to be deflected or displaced with respect to voids provided in another adjacent portion of the coating, thereby creating a tortuous path for any gas to pass through the voids. It is hypothesized that in this manner, the likelihood of the coating inhibiting the passage of gas to the substrate 200 is increased. In other words, with reference to Figure 10 by providing a first portion 220 containing fullerene and metal between the cathode 210 and the second portion 230, the likelihood of any voids extending through the entire thickness of the barrier coating 215 and the cathode 210 is reduced.

[0123] It has been observed that certain metals can act as desiccants. Accordingly, the second portion 230 can contain a metal that acts as a getter or desiccant to inhibit the passage of oxygen and / or water vapor therethrough. It is also hypothesized that the first portion 220 containing metal and fullerene can also act as a desiccant that reacts with any oxygen and / or water vapor transported through the second portion 230 to inhibit the further transport of such oxygen and / or water vapor to the electrode 210 and the substrate 200.

[0124] It has now been discovered that by providing a barrier coating having a portion with a smaller average particle size than adjacent portions of the coating, the overall barrier performance of the coating can be enhanced. With reference to Figure 10For example, the electrode 210 can exhibit a first average particle size, the first portion 220 can exhibit a second average particle size, and the second portion 230 can exhibit a third average particle size. It has now been discovered that the first portion 220, which contains both metal and fullerenes, can exhibit a smaller average particle size than the second portion 230, which in at least some embodiments consists essentially of metal. That is, the second average particle size can be smaller than the third average particle size. In embodiments in which the electrode 210 consists essentially of metal, the second average particle size can also be smaller than the first average particle size. In some embodiments in which the electrode 210 contains a mixture of fullerenes and metal, the first average particle size can depend on a number of factors, such as the average concentration of fullerenes in the electrode 210. Accordingly, in embodiments in which the electrode 210 contains both fullerenes and metal and the electrode 210 can have a lower concentration of fullerenes than the first portion 220, the first average particle size can be greater than the second average particle size, but less than the third average particle size.

[0125] In some cases, it can be particularly advantageous to provide a barrier coating that contains a plurality of first portions having a second average particle size and a plurality of second portions having a third average particle size, wherein the first portions and the second portions are arranged alternately or stacked on top of one another. As explained above, the second average particle size can be smaller than the third average particle size, and thus such a structure can form a barrier coating having enhanced barrier properties.

[0126] For example, in cases in which the electrode 210 consists essentially of metal, such as magnesium, the average particle size of the electrode 210 can be greater than about 60 nm, greater than about 70 nm, greater than about 80 nm, greater than about 100 nm, greater than about 150 nm, greater than about 200 nm, greater than about 300 nm, greater than about 500 nm, or greater than about 1 μιη. In cases in which the electrode 210 contains fullerenes, such as C 60 In some cases in which the electrode 210 contains fullerenes, such as C

[0127] For example, the average particle size of the first portion 220 can be less than about 50 nm, less than about 45 nm, less than about 40 nm, less than about 35 nm, less than about 30 nm, or less than about 25 nm. For example, the average particle size of the first portion 220 can be, for example, from about 20 nm to 50 nm, from about 25 nm to 40 nm, or from about 25 nm to 35 nm.

[0128] For example, the average particle size of the second portion 230 can be greater than about 60 nm, greater than about 70 nm, greater than about 80 nm, greater than about 100 nm, greater than about 150 nm, greater than about 200 nm, greater than about 300 nm, greater than about 500 nm, or greater than about 1 μιη.

[0129] Accordingly, in some embodiments, the average particle size of the second portion 230 can be about 2 times, about 3 times, about 5 times, about 10 times, about 20 times, about 30 times, or about 50 times the average particle size of the first portion 220.

[0130] It is hypothesized that by increasing the average compactness of a portion of a barrier coating, the permeability of the barrier coating can be reduced. It has now been observed that OLED devices provided with a barrier coating that includes a portion having a higher average compactness than other portions exhibit enhanced environmental stability than OLED devices provided with a coating that does not include such a portion. It has now also been found that the environmental stability of an OLED device can be further enhanced by providing a barrier coating that includes two or more, three or more, or four or more portions having a higher compactness than other portions. For greater clarity, the term "average compactness" as used herein is understood to refer to a measure of the degree to which the material forming a coating or a portion thereof is compressed tightly together. Thus, average compactness generally indicates the degree to which any voids can exist within a coating or a portion thereof. Generally, a coating having a relatively high average compactness contains fewer voids (e.g., as measured by the total volume of all voids contained in such a coating) than a coating having a relatively low average compactness. In another example, a portion of a coating that consists of a larger volume fraction of voids will generally exhibit a lower average compactness than another portion of a coating that consists of a smaller volume fraction of voids.

[0131] In some cases, it has been observed that average particle size generally correlates with average compactness. In particular, it has been observed that a portion of a coating having a smaller average particle size generally exhibits a higher compactness than another portion of a coating having a larger average particle size that generally exhibits a lower compactness.

[0132] It is also hypothesized that by increasing the average density of a portion of a barrier coating, the barrier performance of the barrier coating can be enhanced. It has now been observed that OLED devices provided with a barrier coating that includes a portion having a higher average density than other portions exhibit enhanced environmental stability than OLED devices provided with a coating that does not include such a portion. It has now also been found that the environmental stability of an OLED device can be further enhanced by providing a barrier coating that includes two or more, three or more, or four or more portions having a higher density than other portions. For greater clarity, the term "density" as used herein is understood to refer to a measure of mass per unit volume.

[0133] It has now been observed, somewhat surprisingly, that coatings formed from mixtures of metals and fullerenes exhibit higher average densities than coatings formed from metals at least in some cases. For example, it has been observed that while the bulk density of magnesium is about 1.738 g / cm 3 , which is greater than the bulk density of C 60 1.65 g / cm 3 , coatings formed from mixtures of magnesium and C 60 having a concentration of C 60 of 10 vol% exhibit higher average densities than coatings formed from substantially pure magnesium.

[0134] For example, in embodiments in which the first portion 220 comprises a mixture of fullerenes and a metal and in which the second portion 230 comprises a metal, the average density of the first portion can be about 1.1 times, about 1.2 times, about 1.3 times, or about 1.5 times the average density of the second portion.

[0135] In some embodiments, fullerenes can be disposed at the interface between the substrate 200 and the electrode 210, at the interface between the electrode 210 and the first portion 220, and / or at the interface between the first portion 220 and the second portion 230. It is hypothesized that disposing fullerenes at these interfaces can further enhance the barrier properties of the resulting barrier coating 215 due to the fullerenes acting as nucleation centers at these interfaces, thereby causing a change in the microstructure or grain structure of the coating or portions deposited on the fullerenes-treated surfaces. In particular, it is hypothesized that disposing fullerenes at these interfaces causes subsequent portions of the coating deposited on the fullerenes-treated surfaces to undergo a nucleation step before growing. In this way, the microstructure of the subsequent portions can be substantially different from the microstructure of the previous portions.

[0136] In some embodiments, the barrier coating 215 can be electrically conductive. Accordingly, the first portion 220 and the second portion 230 can each be electrically conductive. For example, the barrier coating 215 can form a portion of an electrode, such as a cathode of an optoelectronic device.

[0137] As used herein, materials, layers, and / or coatings can be considered electrically conductive if they readily allow current to flow therethrough under the general operating conditions of the device (e.g., at room temperature). Accordingly, electrically conductive materials can generally exhibit a relatively low resistivity.

[0138] In some embodiments, the barrier coating 215 can be thermally conductive. Accordingly, the first portion 220 and the second portion 230 can each be thermally conductive. In cases where the barrier coating 215 is provided as part of a cathode of a relatively large optoelectronic device, it can be particularly advantageous for the barrier coating 215 to be thermally conductive. In such devices, the barrier coating 215 can help dissipate heat accumulated and / or output by the device.

[0139] In some embodiments, the same evaporation source can be used to deposit the barrier coating 215 and the various portions of the electrode 210. For example, one, two, or three, or more than three evaporation sources can be used to deposit the electrode 210, the first portion 220, and / or the second portion 230. In some embodiments, a metal source and a fullerene source can be used to deposit the barrier coating 215. In these embodiments, for example, the deposition rate of the metal can remain substantially the same or constant throughout the formation of the barrier coating 215, while the deposition rate of the fullerene can be varied accordingly to form various portions of the barrier coating 215 having a desired fullerene content.

[0140] For example, during deposition of the electrode 210, the fullerene source can be turned off, or a shutter can be placed between the fullerene source and the target substrate to substantially inhibit fullerene from being deposited. Alternatively, both the metal source and the fullerene source can be driven during deposition of the electrode 210 to produce an electrode 210 comprising fullerene and metal. In these embodiments, the sources can be configured such that the deposition rate of the metal is, for example, about 5 times, about 10 times, about 15 times, about 20 times, about 30 times, about 50 times, or about 100 times the deposition rate of the fullerene.

[0141] During deposition of the first portion 220, in at least some cases, both the metal source and the fullerene source can be driven to produce an electrode 210 comprising a mixture of fullerene and metal. In these embodiments, the sources can be configured such that the deposition rate of the metal is, for example, about 3 times, about 5 times, about 7 times, about 9 times, about 12 times, about 15 times, or about 19 times the deposition rate of the fullerene. More specifically, the deposition rate of the metal can be, for example, about 3 times to 20 times, 5 times to 20 times, or 7 times to 20 times the deposition rate of the fullerene.

[0142] It has now been discovered that, in at least some cases, the inclusion of an organic material in a barrier coating can not significantly improve the barrier performance of the barrier coating as compared to a similar barrier coating that does not include an organic material. It has also now been discovered, somewhat surprisingly, that the inclusion of an organic material can, in at least some cases, adversely affect barrier performance. Accordingly, in some embodiments, the barrier coating can consist essentially of metal and fullerene.

[0143] Figure 11is a cross-sectional schematic diagram illustrating a portion of an active matrix OLED (AMOLED) device 1100 according to one embodiment. The AMOLED device 1100 includes a first emission region 1131a, a second emission region 1131b, and a third emission region 1131c. The first emission region 1131a, the second emission region 1131b, and the third emission region 1131c can be sub-pixels of the AMOLED device 1100.

[0144] The device 1100 includes a base substrate 1110 and a buffer layer 1112 deposited on a surface of the base substrate 1110. A plurality of thin film transistors (TFTs) 1108a, 1108b, 1108c are then formed on the buffer layer 1112. With particular reference to the TFT 1108c, a semiconductor active region 1114 is formed on a portion of the buffer layer 1112, and a gate insulating layer 1116 is deposited to substantially cover the semiconductor active region 1114. A gate electrode 1118 is then formed on the gate insulating layer 1116, and an interlayer insulating layer 1120 is deposited. A source 1124 and a drain 1122 are formed such that they extend through an opening formed by the interlayer insulating layer 1120 and the gate insulating layer 1116 to contact the semiconductor active layer 1114. An insulating layer 1142 is then formed on the TFTs 1108a, 1108b, 1108c. A first electrode 1144a, 1144b, 1144c is then formed in each of the first emission region 1131a, the second emission region 1131b, and the third emission region 1131c, respectively, on a portion of the insulating layer 1142. As Figure 11As shown, each of the first electrodes 1144a, 1144b, 1144c extends through an opening of the insulating layer 1142 such that it is in electrical communication with the drain 1122 of the respective TFT 1108a, 1108b, 1108c. A pixel defining layer (PDL) 1146a, 1146b, 1146c, 1146d is then formed to cover at least a portion of the first electrodes 1144a, 1144b, 1144c, including the outer edges of each electrode. For example, the PDLs 1146a, 1146b, 1146c, 1146d can comprise an insulating organic material or an insulating inorganic material. An organic layer 1148a, 1148b, 1148c is then deposited on the respective first electrode 1144a, 1144b, 1144c, particularly in the areas between adjacent PDLs 1146a, 1146b, 1146c, 1146d. A second electrode 1150 is deposited to substantially cover both the organic layer 1148a, 1148b, 1148c and the PDLs 1146a, 1146b, 1146c, 1146d. For example, the second electrode 1150 can form a common cathode of the device 1100. A barrier coating 1152 is then deposited on the second electrode 1150. At least a portion of the barrier coating 1152 can be electrically conductive. At least a portion of the barrier coating 1152 can also be reflective to allow light emitted from the emission regions 1131a, 1131b, 1131c of the device 1100 to be emitted or reflected in a direction toward the base substrate 1110. In such embodiments, the device 1100 can be a bottom-emitting AMOLED device.

[0145] The barrier coating 1152 can comprise a first portion and a second portion. Various embodiments of barrier coatings comprising a first portion and a second portion have been described above, and are understood to be applicable to the barrier coating 1152 shown in FIG. 11. Figure 11

[0146] Figure 12 ​An AMOLED device 1101 according to another embodiment is shown, wherein the device 1101 includes a common organic layer 1148 disposed on the surface of the first electrodes 1144a, 1144b, 1144c and the PDLs 1146a, 1146b, 1146c, 1146d. The device 1101 can be configured to emit light of a substantially white emission spectrum from the first emission region 1131a, the second emission region 1131b, and the third emission region 1131c. A color filter 1201 can be provided on the substrate 1110 so as to subsequently convert the white emission spectrum to a desired emission spectrum for each emission region or sub-pixel 1131a, 1131b, 1131c. For example, the color filter 1201 can be configured to convert light emitted by the first emission region 1131a to blue light, convert light emitted by the second emission region 1131b to green light, and convert light emitted by the third emission region 1131c to red light. However, it should be understood that the color filter 1201 can convert light emitted by each emission region to any color or spectrum.

[0147] Figure 13 An embodiment is shown in which the optoelectronic device 1301 is provided with the electrode 210 and a barrier coating 1315. In particular, the barrier coating 1315 includes two first portions 1320a, 1320b and two second portions 1330a, 1330b. Various embodiments of barrier coatings including a composition of first portions and second portions have been described, and accordingly, such description is understood to apply to each of the various portions of the barrier coating 1315 shown in Figure 13 Figure 13 In the embodiment shown, the first portions 1320a, 1320b and the second portions 1330a, 1330b are arranged alternately, such that a first portion 1320a is disposed on the electrode 210, and a second portion 1330a is disposed on the first portion 1320a. A first portion 1320b is disposed on the second portion 1330a, and a second portion 1330b is disposed on the first portion 1320b. In this manner, adjacent second portions 1330a, 1330b are interposed by a first portion 1320b.

[0148] Figure 14 An embodiment of an optoelectronic device 1401 is shown, wherein the device 1401 includes the electrode 210 and a barrier coating 1415. In particular, the barrier coating 1415 includes three first portions 1420a, 1420b, 1420c and three second portions 1430a, 1430b, 1430c. Various embodiments of barrier coatings including a composition of first portions and second portions have been described, and accordingly, such description is understood to apply to each of the various portions of the barrier coating 1415 shown in Figure 14 Figure 14 ​​In the embodiment, the first parts 1420a, 1420b, 1420c and the second parts 1430a, 1430b, 1430c are arranged alternately and stacked on top of each other.

[0149] In some embodiments where additional first and second portions are provided, the additional portions of the barrier coating can be formed integrally or continuously with each other and with the first and second portions.Furthermore, the electrode 210 and the barrier coating can be formed integrally or continuously with each other.

[0150] Although already Figure 13 and Figure 14 1 and 2, wherein two or three additional barrier coating portions are provided on substrate 200, but it should be understood that any number of barrier coating portions may be provided. For example, four or more, five or more, or six or more barrier coating portions may be provided in the device. In some embodiments, a device or substrate may be provided with multiple barrier coatings, wherein the multiple barrier coatings are provided on top of each other or vertically stacked.

[0151] Figure 15A One embodiment of a barrier coating 215 is shown that includes an electrode 210, a first portion 220, and a second portion 230. In the embodiment of Figure 15, a perimeter or edge 1512 of the electrode 210 is shown coated or covered by the first portion 220. A perimeter or edge 1522 of the first portion 220 is also shown coated or covered by the second portion 230. This embodiment can be particularly advantageous for inhibiting lateral penetration or edge ingress of gases, such as air and water vapor, toward the electrode 210 and the portion of the substrate 200 coated by the electrode 210.

[0152] Figure 15B An embodiment is shown in which the electrode 210, the first portion 220, and the second portion 230 are integrally formed on the substrate 200, and portions of the electrode 210 and the barrier coating 215 are provided with different concentrations of fullerenes 226. Figure 15B In some embodiments, the electrode 210, the first portion 220, and the second portion 230 can each include a mixture of a metal 228 and fullerenes 226. When forming the electrode 210 and the barrier coating 215, the concentration of the fullerenes 226 can be varied, for example, by adjusting the relative deposition rate of the fullerenes relative to the metal deposition rate. In this manner, the first portion 220 can be provided with a higher concentration of fullerenes 226 than the electrode 210 or the second portion 230. Although not specifically illustrated, it should be understood that in some embodiments, the electrode 210 and / or the second portion 230 can be substantially free of fullerenes 226, or can be free of fullerenes 226.

[0153] Figure 15CShown Figure 15B Another embodiment of Figure 15C In the embodiment of the present invention, an additional first portion 1620 comprising a mixture of fullerenes 226 and metal 228 is provided on the second portion 230 of the barrier coating 215. The additional first portion 1620 can be formed integrally or continuously with the first portion 220 and the second portion 230, for example, by continuing to co-deposit the fullerenes and metal in the manner described above. The concentration of fullerenes 226 in the additional first portion 1620 can be comparable to the concentration of fullerenes 226 in the first portion 220. Alternatively, the concentration of fullerenes 226 in the additional first portion 1620 can be less than or greater than the concentration of fullerenes 226 in the first portion 220. In at least some embodiments, the concentration of fullerenes 226 in the additional first portion 1620 is greater than the concentration of fullerenes 226 in an adjacent portion of the additional first portion 1620 (e.g., the second portion 230).

[0154] Figure 15D Shown Figure 15C , wherein an additional second portion 1630 is provided on the additional first portion 1620 to form the barrier coating 215. The additional second portion 1630 can be described in substantially the same manner as the second portion 230, and thus a description thereof is omitted for simplicity.

[0155] It should be understood that, except Figure 15D In addition to the coatings and portions shown in FIG, other coatings and portions may be disposed on or between various portions of the barrier coating 215 and the additional barrier coating portions 1620 , 1630 .

[0156] For example, the electrode 210 and barrier coating 215 can be formed by continuously depositing the metal 228 while adjusting the relative deposition rates of the fullerenes to achieve a desired concentration of fullerenes in various portions of the coating. For example, the relative deposition rate of the fullerenes can be adjusted by reducing the evaporation rate of the fullerenes and / or by using a baffle to block the fullerene vapor flow during the deposition process to inhibit at least a portion of the fullerene vapor flow from being incident on the deposition target. The relative deposition rate of the fullerenes can be varied in a continuous or wave-like manner, or can be varied in a discontinuous manner. For example, the deposition of fullerenes can gradually decrease and increase during the formation of the coating, or the deposition of fullerenes can be abruptly stopped and started during the formation of the coating.

[0157] It should be understood that, as used herein, fullerene is understood to be any carbon-based molecule that is a hollow sphere, ellipsoid, tube, or any other three-dimensional shape. More specifically, fullerene is understood to include carbon-based molecules whose atoms are arranged in closed hollow spheres as well as carbon-based molecules whose atoms form elongated hollow tubular structures. Thus, examples of fullerenes include, but are not limited to, buckminsterfullerene (i.e., C60 ), C 70 、C 76 、C 84 , multi-walled carbon nanotubes (CNTs) and single-walled CNTs, including conductive CNTs and semiconducting CNTs. It should also be understood that fullerenes can also be a combination or mixture of several different types of fullerenes. In addition, it should be understood that fullerene derivatives such as functionalized fullerenes and doped fullerenes can also be used. Therefore, fullerene molecules can contain various functional groups and / or non-carbon atoms. For example, phenyl-C61-butyric acid methyl ester (PCBM) can be used as a fullerene.

[0158] It should also be understood that the magnesium described herein can be substantially pure magnesium or a magnesium alloy. It should be understood that the purity of substantially pure magnesium can be greater than 99%, 99.9%, or higher. The magnesium alloy can include various magnesium alloys known in the art.

[0159] Example

[0160] Various aspects of the invention will now be illustrated with reference to the following examples, which are not intended to limit the scope of the invention in any way.

[0161] All exemplary OLED devices described herein were manufactured using the same device structure. Specifically, the general device structure used for all exemplary OLED devices was as follows: anode / hole injection layer / hole transport layer / emitter layer / electron transport layer / electron injection layer / conductive coating. In various evaluation samples, one or more additional coatings or layers were deposited on the conductive coating to evaluate the barrier properties of the resulting barrier coating. All exemplary OLED devices were then packaged and tested for environmental stability by subjecting them to accelerated aging conditions of 85°C and 85% relative humidity. Environmental stability was evaluated by measuring the percentage of non-emissive area of ​​each OLED sample at different times during the aging process. As is known, when the emissive area of ​​an OLED degrades due to contact with air and / or water, that area will no longer emit light. Therefore, the environmental stability of an OLED sample can be evaluated by detecting the percentage of the emissive area of ​​the OLED that becomes non-emissive over time due to degradation.

[0162] In all of the embodiments described below, the magnesium used to form the various coatings and portions thereof of the exemplary OLED devices is substantially pure magnesium having a purity greater than about 99%. Similarly, the aluminum used to form the various coatings and portions thereof of the exemplary OLED devices is substantially pure aluminum having a purity greater than about 99%.

[0163] Example A

[0164] The device sample 1 was manufactured according to the general device structure described above. Specifically, a 1 nm thick C 60Coating A 500 nm thick magnesium coating was then deposited to produce the cathode.

[0165] By depositing 1 nm thick C 60 Coating A 2500 nm thick magnesium coating was then deposited to form the cathode to fabricate device sample 2.

[0166] Figure 16 is a plot of the percentage of non-emissive area versus the time period over which the samples were subjected to accelerated aging conditions. It can be seen that while Samples 1 and 2 showed significant degradation during aging, Sample 2, which had a thicker magnesium coating than Sample 1, degraded less based on the percentage of non-emissive area.

[0167] Example B

[0168] Sample 3 was fabricated according to the general device structure described above. Specifically, a 1 nm thick C 60 coating, then in C 60 A 200 nm thick magnesium coating was deposited on the coating to form a conductive coating. Then, three additional coatings were sequentially deposited on the magnesium coating, one on top of the other. 60 coating, and then depositing a 400nm thick magnesium coating to form each additional coating group. Each 100nm thick Mg:C 60 C in coating 60 The concentration is about 10% by volume.

[0169] Sample 4 was fabricated according to the general device structure described above. Specifically, a 1 nm thick C 60 coating, then in C 60 A 200 nm thick magnesium coating was deposited on the conductive coating. Three additional coatings were then sequentially deposited on the magnesium coating, one on top of the other. A 10 nm thick layer of 2,2',2"-(1,3,5-benzotriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) was deposited, followed by a 1 nm thick layer of C 60 coating, and then depositing a 500 nm thick magnesium coating to form each group of additional coatings.

[0170] Figure 17 is a plot of the percentage of non-emissive area versus the time period over which the samples were subjected to accelerated aging conditions. It can be seen that Sample 3 performs significantly better than Sample 4, as no detectable change in the percentage of non-emissive area was observed for Sample 3 even after 1200 hours of aging, while over 50% of the emissive area of ​​Sample 4 had degraded after the same time period.

[0171] Example C

[0172] Sample 5 was fabricated according to the general device structure described above. Specifically, a 1 nm thick C 60 coating, then in C 60 A 200 nm thick magnesium coating was deposited on the coating to form a conductive coating. Four additional coatings were then sequentially deposited on the magnesium coating, one on top of the other. 60 coating, and then depositing a 200nm thick magnesium coating to form each additional coating group. Each 100nm thick Mg:C 60 C in coating 60 The concentration is about 10% by volume.

[0173] Sample 6 was fabricated according to the general device structure described above. Specifically, a 1 nm thick C 60 coating, then in C 60 A 200nm thick magnesium coating is deposited on the coating to form a conductive coating. Then a 1200nm thick Mg:C 60 Coating. Mg:C 60 C in coating 60 The concentration is about 10% by volume.

[0174] Figure 18 is a graph of the percentage of non-emissive area versus the time period over which the samples were subjected to accelerated aging conditions. As can be seen, Samples 5 and 6 performed comparably for approximately the first 650 hours of aging. However, Sample 5 performed better than Sample 6 after approximately 650 hours of aging. Specifically, the percentage of non-emissive area in Sample 6 gradually increased to over 3% after approximately 800 hours of aging, while relatively little change in the percentage of non-emissive area was observed for Sample 5 after approximately 800 hours of aging.

[0175] Example D

[0176] Three evaluation samples were made to evaluate the effect of varying the Mg:C 60 Effect of fullerene concentration in the coating.

[0177] Samples 7, 8, and 9 were fabricated according to the general device structure described above. Specifically, for each sample, a 1 nm thick C 60 coating, then in C 60 A 200 nm thick magnesium coating was deposited on the coating to form a conductive coating. For each sample, three additional coatings were then sequentially deposited on the magnesium coating. 60 coating, and then deposited a 300nm thick magnesium coating to form each group of additional coatings. For sample 7, each 100nm thick Mg:C 60 C in coating 60at about 0.2 volume percent. For sample 8, each 100 nm thick Mg:C 60 C in the coating 60 at about 1 volume percent. For sample 9, each 100 nm thick Mg:C 60 C in the coating 60 at about 5 volume percent.

[0178] Figure 19 is a plot of the percentage of non-emissive area versus the time period the sample was subjected to accelerated aging conditions. Based on the results, sample 7 performed significantly worse than sample 8 or sample 9. In particular, the percentage of non-emissive area for sample 8 or sample 9 did not change substantially during the first 600 hours of aging, while the percentage of non-emissive area for sample 7 increased to about 20% after about 600 hours of aging. It was also observed that sample 9 performed better than sample 8 after about 750 hours of aging. Specifically, the percentage of non-emissive area for sample 8 increased to about 20% after about 1330 hours, while the percentage of non-emissive area for sample 9 was about 5% after about 1330 hours.

[0179] Example E

[0180] Sample 10 was fabricated according to the general device structure described above. In particular, the conductive coating was formed by depositing a 1 nm thick C 60 coating on the electron injection layer, followed by depositing a 100 nm thick magnesium coating on the C 60 coating. Four additional sets of coatings were then deposited on the conductive coating, one on top of the other. Each set of additional coatings was formed by depositing a 50 nm thick Mg:C 60 coating, followed by depositing a 200 nm thick magnesium coating. Each 50 nm thick Mg:C 60 coating had a C 60 concentration of about 15 volume percent.

[0181] Sample 11 was fabricated according to the general device structure described above. In particular, the conductive coating was formed by depositing a 200 nm thick aluminum coating on the surface of the electron injection layer. Four additional sets of coatings were then deposited on the conductive coating, one on top of the other. Each set of additional coatings was formed by depositing a 50 nm thick Mg:C 60 coating, followed by depositing a 200 nm thick magnesium coating. Each 50 nm thick Mg:C 60 coating had a C 60 concentration of about 15 volume percent.

[0182] Sample 12 was fabricated by depositing a 200 nm thick aluminum coating to form the cathode.

[0183] Figure 20is a graph of the percentage of non-emissive area relative to the time period over which the samples were subjected to accelerated aging conditions. Based on the results, Sample 12 performed significantly worse than either Sample 10 or Sample 11. Specifically, while the percentage of non-emissive area did not change significantly during the first 300 hours of aging for Sample 10 or Sample 11, the percentage of non-emissive area for Sample 12 increased to approximately 90% after approximately 300 hours of aging.

[0184] Example F

[0185] A number of samples were prepared and analyzed using a scanning electron microscope (SEM) to determine the morphology of various parts of the samples.

[0186] The first sample was prepared by depositing the following layers or coatings on the surface of a silicon substrate in the order shown: a magnesium coating of approximately 2 μm thick; a coating having 15% by volume of C 60 The Mg:C layer is about 400 nm thick. 60 coating; and a magnesium coating approximately 2 μm thick.

[0187] The second sample was prepared by depositing the following layers or coatings on the surface of a silicon substrate in the order shown: Mg:C 60 A coating wherein the concentration of fullerenes gradually decreases from about 15% by volume to 0% by volume as the coating forms; and a magnesium coating having a thickness of about 1.4 μm. Figure 21 A SEM micrograph showing a cross section of the second sample is provided in .

[0188] The third sample was prepared by depositing the following layers or coatings on the surface of a silicon substrate in the order shown: a magnesium coating of about 2 μm thick; a Mg:C coating of about 1.6 μm thick; 60 A coating wherein the concentration of fullerenes gradually decreases from about 15% by volume to 0% by volume as the coating forms; and a magnesium coating having a thickness of about 1.5 μm. Figure 22 A SEM micrograph showing a cross section of the third sample is provided in .

[0189] The fourth sample was prepared by depositing the following layers or coatings on the surface of a silicon substrate in the order shown: a magnesium coating of about 1 μm thick; a C coating of about 10 nm thick; 60 coating; and a magnesium coating of about 1 μm thick. Figure 23 A SEM micrograph showing a cross section of the fourth sample is provided in . Figure 23 In the figure, reference numeral 2310 is used to indicate the approximate region corresponding to the first 1 μm thick magnesium coating, and reference numeral 2320 is used to indicate the region corresponding to the 10 nm thick C 60 The approximate area of ​​the coating is indicated by reference numeral 2330, and the approximate area corresponding to the second 1 μm thick magnesium coating is indicated by reference numeral 2330. Figure 23 As can be seen in the figure, due to the presence of C at the interface60 The microstructure or growth pattern of the coating, magnesium, is disrupted at the interface between the first magnesium coating and the second magnesium coating. Specifically, it can be observed that the microstructure or grain structure of the first magnesium coating does not extend to the second magnesium coating disposed above the first magnesium coating.

[0190] A fifth sample was prepared by sequentially depositing three sets of coatings on a silicon substrate, each set of coatings comprising a Mg:C 60 coating, followed by a magnesium coating of about 100 nm in thickness. As the Mg:C 60 coating formed, the C 60 concentration in each Mg:C 60 decreased gradually from about 10% to 0%. In Figure 24 A SEM micrograph showing a cross-section of the fifth sample is provided in FIG. 24. In Figure 24 corresponding to the first set of coatings, using reference numeral 2420 to denote an approximate area corresponding to the second set of coatings, and using reference numeral 2430 to denote an approximate area corresponding to the third set of coatings.

[0191] A sixth sample was prepared by sequentially depositing three sets of coatings on a silicon substrate, each set of coatings comprising a Mg:C 60 coating, followed by a magnesium coating of about 300 nm in thickness. As the Mg:C 60 coating formed, the C 60 concentration in each Mg:C 60 decreased gradually from about 10% to 0%. In Figure 25 A SEM micrograph showing a cross-section of the fifth sample is provided in FIG. 24. In Figure 25 corresponding to the first set of coatings, using reference numeral 2520 to denote an approximate area corresponding to the second set of coatings, and using reference numeral 2530 to denote an approximate area corresponding to the third set of coatings.

[0192] Based on the analysis of the fifth and sixth samples, it was determined that the average compactness of the entire coating was increased by providing a fullerene-containing portion as compared to a substantially pure magnesium coating of similar thickness. In addition, it was determined that the average grain size of a substantially pure magnesium coating deposited between adjacent Mg:C 60 coatings was lower than the average grain size of a substantially pure magnesium coating deposited in the absence of adjacent Mg:C 60 coatings.

[0193] Based on the analysis of the above samples, the average grain size in the various coatings was determined and is summarized in the table below.

[0194] Composition Average particle size [Mg (no adjacent Mg:C 60 coating) about 0.98 μm Mg (with adjacent Mg:C 60 coating) <0.3 μm Mg:C 60 (15 volume % C 60 )]]> <0.3 μm Mg:C 60 (linear decrease: 15 vol% to 0 vol% C 60 )]]> <0.3 μm Mg:C 60 (linear decrease: 10 vol% to 0 vol% C 60 )]]> <0.2 μm

[0195] Example G

[0196] X-ray diffraction (XRD) was used to analyze the average particle size in the magnesium-based coatings and the effect of the presence of fullerenes on the average particle size in such coatings. Based on the analysis results, it was determined that the average particle size or crystallite size in a Mg:C 60 coating containing 10 vol% C 60 was about 29 nm, and that the detection limit of XRD for the average particle size or crystallite size in a coating containing 99.9% pure magnesium was greater than about 60 nm.

[0197] Example H

[0198] Two samples were prepared to determine the effect of fullerenes on the average density of the resulting coatings.

[0199] A first sample was prepared by depositing a substantially pure magnesium coating on the surface of a silicon substrate.

[0200] A second sample was prepared by depositing a coating containing a mixture of magnesium and C 60 on the surface of a silicon substrate. The average concentration of C 60 in the coating was about 10 vol%.

[0201] A quartz crystal microbalance (QCM) was used to monitor the deposition process during sample preparation to ensure that the total mass of material deposited on the silicon surface for the first and second samples was substantially the same.

[0202] The thickness of the coatings formed in the first and second samples was then measured using a surface profilometer. The following table summarizes the results of the thickness measurements.

[0203] Coating composition Coating thickness Magnesium 1.95 μm Mg:C 60 (10 volume % C 60 )]]> 1.58 μm

[0204] Based on the above, the Mg:C 60 coating was thinner and therefore exhibited a higher average density compared to the magnesium coating. Specifically, it was determined that the density of the coating formed from the mixture of magnesium and C 60 (10 vol% C 60 ) had an average density that was about 1.2 times the average density of the magnesium coating.

[0205] As used herein, the terms "substantially," "essentially," "about," and "approximately" are used to represent and describe small variations away from a perfect or exact value. When used in conjunction with a condition or situation, these terms can refer to instances where the condition or situation is met exactly, as well as instances where the condition or situation is met approximately or nearly. For example, when used in conjunction with a numerical value, these terms can refer to a range of variation that is less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%.

[0206] Further, amounts, ratios, and other numerical values are sometimes presented herein in a range format. It is to be understood that the range format is used only for convenience and brevity and should be taken as a preciser statement for the subject invention. To clearly describe the subject invention the above ranges are used herein before and subsequently within the specification.

[0207] While the application has been described with reference to certain implementations, modifications thereto will occur to those skilled in the art. Any implementation described herein is included within the scope of the present application and is not intended to limit the application in any way. Any drawings provided herein are included solely for purposes of illustrating the aspects of the application and are not intended to be made part of the present application unless specifically designated as such. The scope of the claims appended hereto should not be limited to the preferred embodiments set forth in the detailed description above but should be given the broadest interpretation available to them under the circumstances. All publications cited herein are incorporated herein by reference in their entirety.

Claims

1. A flexible OLED device, comprising: Flexible substrates, a first electrode, arranged at a proximal end of the substrate, a second electrode disposed at a distal end of the substrate, at least one organic layer disposed between the first electrode and the second electrode, and a barrier coating comprising a first portion comprising fullerenes and a second portion comprising a metal and fullerenes, the barrier coating being disposed on the second electrode such that the second electrode is disposed between the at least one organic layer and the barrier coating, wherein the fullerene is provided at at least one of an interface between the second electrode and the first portion and an interface between the first portion and the second portion, and The concentration of fullerenes in the first portion is greater than the concentration of fullerenes in the second portion.

2. The flexible OLED device according to claim 1, wherein: The barrier coating has a thickness of at least one of 100-5000 nm, 100-2500 nm, 100-2000 nm, 100-1500 nm, 100-1000 nm, 100-800 nm, 100-600 nm, 100-500 nm, 150-500 nm, 200-500 nm, and 300-500 nm.

3. The flexible OLED device according to claim 1, wherein: The first portion also includes a metal.

4. The flexible OLED device according to claim 1, wherein: The concentration of fullerenes in the first portion varies throughout the first portion.

5. The flexible OLED device according to claim 1, wherein: The average density of the first portion is at least the average density of the second portion.

6. The flexible OLED device according to claim 1, wherein: The compactness of the first portion is at least the compactness of the second portion.

7. The flexible OLED device according to claim 1, wherein: An average grain size of the first portion is no greater than an average grain size of the second portion.

8. The flexible OLED device according to claim 3, wherein: At least one of the metals in the first portion and the metals in the second portion is selected from at least one of magnesium, cadmium, zinc, or any combination thereof.

9. The flexible OLED device according to claim 4, wherein: The first portion includes a first region and a second region, and a concentration of fullerenes in the first region is different from a concentration of fullerenes in the second region.

10. A barrier coating for a photovoltaic device, comprising: electrode; a first portion disposed on an electrode of the device, and a second portion disposed on a side of the first portion opposite to the electrode, such that the first portion is disposed between the electrode and the second portion; wherein the first portion comprises fullerenes and the second portion comprises metal and fullerenes, At least a portion of the fullerene has a metal nucleated around it, and The concentration of fullerenes in the first portion is greater than the concentration of fullerenes in the second portion.

11. The barrier coating of claim 10, wherein: The first portion also includes a metal.

12. The barrier coating of claim 11, wherein At least one of the metals in the first portion and the metals in the second portion is selected from at least one of magnesium, cadmium, zinc, or any combination thereof.

13. The barrier coating of claim 10, wherein: The concentration of fullerenes in the first portion varies throughout the first portion.

14. The barrier coating of claim 13, wherein: The first portion includes a first region and a second region, and a concentration of fullerenes in the first region is different from a concentration of fullerenes in the second region.

15. An electrode provided on a substrate of a semiconductor device, the electrode including a barrier coating as a portion thereof, wherein the barrier coating includes a first portion and a second portion, and wherein the electrode is formed by: depositing a first conductive material to form a conductive coating on the surface of the substrate; depositing fullerene to form the first portion on the conductive coating; as well as depositing a second conductive material and fullerene to form the second portion on the first portion, The concentration of fullerenes in the first portion is greater than the concentration of fullerenes in the second portion.

16. The electrode according to claim 15, wherein The operation of depositing the first conductive material includes co-depositing the first conductive material and fullerene to form the conductive coating.

17. The electrode according to claim 15, wherein The operation of depositing the fullerene includes co-depositing the fullerene and a third conductive material to form the first portion.

18. The electrode according to claim 17, wherein The first conductive material, the second conductive material, and the third conductive material are all metals.

19. The electrode according to claim 18, wherein The metal is selected from at least one of the following: magnesium, cadmium, zinc or any combination thereof.

20. The electrode according to claim 15, wherein The concentration of fullerenes in the first portion varies throughout the first portion.

21. The electrode according to claim 20, wherein The first portion includes a first region and a second region, and a concentration of fullerenes in the first region is different from a concentration of fullerenes in the second region.

22. A photoelectric device comprising: the first electrode, a second electrode configured as an electrode according to any one of claims 15 to 21, and At least one organic layer is disposed between the first electrode and the second electrode such that the barrier coating of the second electrode is positioned away from the at least one organic layer.

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