WO2018109720A1

WO2018109720A1 - Fabrication of internal light extraction film used in organic light emitting diodes

Info

Publication number: WO2018109720A1
Application number: PCT/IB2017/057959
Authority: WO
Inventors: Sang Hoon Kim; Hoo Keun Park
Original assignee: Sabic Global Technologies B.V.
Priority date: 2016-12-14
Filing date: 2017-12-14
Publication date: 2018-06-21

Abstract

A process for fabricating an internal extraction film (100) including providing a substrate as a donor substrate; treating the donor substrate with a photosensitized oxide process; coating an internal extraction layer (130) on the treated donor substrate; applying a transfer resin (120) to the internal extraction layer; laminating the transfer resin with a plastic substrate (110) by roller; curing the transfer resin; and detaching the donor substrate.

Description

FABRICATION OF INTERNAL LIGHT EXTRACTION FILM USED IN ORGANIC

LIGHT EMITTING DIODES

Technical Field

[0001] The present disclosure generally relates to fabrication of an internal light extraction layer used in organic light emitting diodes (OLEDs). More particularly, the present disclosure relates to fabrication of an internal light extraction film by a transfer process.

Background

[0002] Today, organic light emitting diodes (OLEDs) are increasingly used in lighting applications because they are more energy efficient than other conventional lighting sources. OLEDs typically have a stacked structure composed of one or more organic layers positioned between two electrodes. At least one of the two electrodes, either the anode or the cathode electrode is formed from a transparent conductive material, which enables the light emitted from the OLED to be visible.

[0003] The transparent conductive material used as an electrode should possess certain properties such as low resistivity and high optical transmittance to produce an OLED device with desirable performance. Indium tin oxide (ITO) is a transparent electrode material that is useful in OLED applications due to its high transparency in the visible wavelength range. For example, ITO is commonly used in many liquid crystal display LCD applications.

Transparent conductive oxides, such as ITO, however, are problematic for flexible OLED devices because they are brittle and prone to cracking under stress.

[0004] Materials such as silver nanowires (AgNW) or other metal nanowires, metal nanoparticles, carbon nanotubes, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), and graphene have emerged as alternatives to ITO for flexible OLED applications. These materials possess advantageous properties such as strong adhesion with the substrate, wettability, and high glass transition temperatures that make them desirable as electrode materials. Silver nanowire, however, has emerged as a promising alternative to ITO due to its high conductivity and optical transmittance. Silver nanowire has also demonstrated the appropriate mechanical flexibility as shown by its bending properties and the electrical resistivity (10 ohms per square (ohm/sq)) needed for large-scale production.

[0005] Despite the aforementioned advantages, electrodes formed using silver nanowires suffer from challenges associated with higher surface roughness. For example, when silver nanowires are deposited on a surface the nanowires overlap each oilier creating protrusions and causing surface roughness. While these portions of overlapping nanowires increase the conductivity of the electrode, higher surface roughness lowers the efficiency and the stability of the overall device. Therefore, it is important that the surface characteristics of electrodes formed using silver nanowire are improved to allow for stable and efficient devices.

[0006] One approach to improving the surface roughness of silver nanowires has been to form a top coating of PEDOT:PSS over the silver nanowires. The acidity of the

PEDQT:PSS, however, tends to negatively affect the properties of the silver nanowire and the device stability. Electrodes formed using hybrid solutions that combine silver nanowires and PEDOT:PSS have also been tested and produce similar results. Another approach to improving surface roughness involves welding to fill in the existing gaps in a deposited layer of silver nanowire. The welding process may improve surface roughness, but it significantly increases the production costs and complexity of fabrication.

[0007] Another property of significance in OLEDs is the external quantum efficiency of the material. Conventional OLEDs still exhibit relatively low values because of the presence of intrinsic light confinements. To extract light trapped in the device, various light extraction methods have been proposed and applied including external and internal extraction methods. External extraction extracts confined light at the glass/air interface. Light in the organic layer, which has a high refractive index, however remains confined. To fully extract the confined light, it is desirable to develop internal light extraction methods. Use of high refractive index layers with scattering particles have been proposed. While these layers improve light extraction, they have introduced additional complexity in fabrication and an undesirable increase in surface roughness.

[0008] These and other shortcomings are addressed by aspects of the present disclosure. Summary

[0009] In accordance with one example of the disclosure, a process for fabricating an internal extraction film by a transfer process is provided. The process includes (a) providing a substrate as a donor substrate; (b) treating the donor substrate with a photosensitized oxide process; (c) coating an internal extraction layer on the treated donor substrate; (d) applying a transfer resin to the internal extraction layer; (e) laminating the transfer resin with a plastic substrate by roller; (f) curing the transfer resin; and (g) detaching the donor substrate.

According to another example, the substrate is hydrophobic. According to a further example, the substrate is glass. According to another aspect, the photosensitized oxide process is an ultraviolet ozone process. [0010] An internal extraction film prepared by a process including (a) providing a substrate as a donor substrate; (b) treating the donor substrate to obtain a contact angle ranging from about 85 to about 92 degrees; (c) coating an internal extraction layer on the treated donor substrate; (d) applying a transfer resin to the internal extraction layer; (e) laminating the transfer resin with a plastic substrate by roller; (f) curing the transfer resin; and (g) detaching the donor substrate.

Brief Description of the Drawings

[0011] The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become apparent and be better understood by reference to the following description of one example of the disclosure in conjunction with the accompanying drawings, wherein:

[0012] FIG. 1 is an edge view of the conductive patterned film on a substrate according to one example of the present disclosure.

[0013] FIG. 2A is a schematic illustration of a step of treating a donor substrate according to one example of the present disclosure.

[0014] FIG. 2B is a schematic illustration of a step of coating a donor substrate with an internal extraction material.

[0015] FIG. 2C is a schematic illustration of a step of laminating the internal extraction material coated donor substrate to a plastic substrate by a transfer resin according to one example of the present disclosure.

[0016] FIG. 2D is a schematic illustration of curing the transfer resin according to one example of the present disclosure.

[0017] FIG. 2E is a schematic illustration of delaminating the donor substrate according to one example of the present disclosure.

[0018] FIG. 2F is a schematic illustration of a patterned electrode after the donor substrate has been removed according to one example of the present disclosure.

[0019] FIG. 3 is side-by-side image of an internal extraction layer on a glass substrate on one side and, on a second side, a transferred internal extraction layer formed according to an example of the present disclosure with the delaminated glass layer shown.

[0020] FIG. 4 is a side-by-side comparison of images from a spin-coated internal extraction layer and an internal extraction layer formed by a transfer process according to an example of the present disclosure. [0021] FIG. 5 is a schematic illustration of a roll-to-roll transfer process for laminating the internal extraction layer to a plastic substrate.

Detailed Description

[0022] The present disclosure provides a process for fabricating an internal extraction film. The process includes placing an internal extraction layer on a plastic substrate by a transfer process. The transfer process improves surface roughness by sandwiching the internal extraction layer between a donor substrate and a transfer resin before the plastic substrate is applied, in general, a donor substrate, which may be hydrophobic glass, is provided. The substrate may be treated before applying an internal extraction layer thereto. A transfer resin is applied over the internal extraction layer. A plastic substrate is laminated with transfer resin, as by rolling. Afterwards, the structure is cured causing the transfer resin to transfer to the plastic substrate. The donor substrate is then detached leaving an internal extraction film comprising a plastic substrate, transfer resin and internal extraction layer in a stacked configuration.

[0023] FIG. 1 illustrates an internal extraction film 100 formed using the process according to one example of the present disclosure. As shown in FIG. 1, the internal extraction film 100 may have a stacked structure. The internal extraction film 100 includes a plastic substrate 110, a transfer resin 120 and an internal extraction layer 130.

[0024] FIGS. 2A-2F illustrate examples of the various process steps that may be used to fabricate an internal extraction film 100. In one example, the internal extraction film 100 may be transparent. The internal extraction film 100 may be used to form OLEDs, touch displays, flexible electronics, or other photovoltaic devices. Other uses for the internal extraction film 100, however, are contemplated and the present disclosure is not imuted in this regard.

[0025] With reference to FIGS 2A-2F, a process for fabricating an internal extraction film 100 according to examples of the disclosure is shown. In general, the process includes providing an internal extraction material 140 on a donor substrate 105 and joining an internal extraction layer 130 to a plastic substrate 110 by a transfer process.

[0026] With reference to FIG. 2A, donor substrate 105 is provided to receive internal extraction material 140. The donor substrate 105 may be any suitable substrate material for supporting the internal extraction material. Suitable donor substrate materials may include, but are not limited to, glass, plastics, semiconductor materials such as silicon, and ceramics. Specific examples of the donor substrate material may include, but are not limited to a film made of plastic such as polyethylene terephthalate (PET), poly methyl acrylate (PMA), poly methyl methacrylate (PMMA), poly acrylate copolymer, polyurethane (PU), polyurethane copolymer, cellulose acetate, polystyrene (PS), polystyrene co-polymer, poly imide (Pi) and the like. In other examples, a glass substrate material is used. In still another example, the donor substrate material is a hydrophobic material. The example shown in FIG. 2A depicts a hydrophobic glass.

[0027] To prepare the donor substrate 105 for receiving internal extraction material 140, a photo-sensitized oxidation process may be employed such as a UV-ozone (UVO3) method. To that end, a light source is provided to expose donor substrate 105 to short wavelength radiation, for example, 180nm - 260nm. The UVO3 treatment may be applied for a time period suitable to prepare the surface of donor substrate 105 to receive interna], extraction material 140. For example, exposure from about 30 to about 60 seconds is suitable for smooth detachment. In the example shown, a very thin layer of extraction material 140 is coated on donor substrate 105. As a result, coating of extraction material 140 is sensitive to the surface energy of the substrate surface, and treatment facilitates coating by reducing the hydrophobicity of substrate material. Surface energy may be measured by a contact angle method. In one example, a hydrophobic donor substrate, without surface treatment fell in the range of about 98 to 105 degrees. For smooth detachment, a contact angle of about 85 to about 92 degrees was found suitable. Surface treatment such as those described above, brought the donor substrate to a contact angle within this range. It will be understood that other surface treatments may be used to achieve the same results or to suit a different type of internal extraction material than the material in the example. Therefore, the UVO treatment should not be considered limiting.

[0028] In terms of the period of exposure, a balance between good adhesion and the ability to detach the donor substrate is achieved. In the example, the UVO3 treatment is not applied for an exposure sufficient to attach internal extraction material 140 to donor substrate 105, but short enough to prevent curing of the material to donor substrate 105.

[0029] With reference to FIG. 2B, internal extraction material 140 is coated on a surface of donor substrate 105, for example, by spin coating or a Mayer bar. It will be understood that other coating methods may be used including but not limited to slot die coating, micro gravure coating, screen printing, spray coating, inkjet printing, and the like.

[0030] The internal extraction material 140 may be deposited on donor substrate 105 as shown in FIG. 2B. A solution containing the extraction material 140 may be initially prepared. The solution may include the internal extraction material 140 and an aqueous solvent. The aqueous solvent may include alcohol and/or other organic solvents. The solution may further include a polymer binder. The polymeric binder may be a curable resin including but not l imited to polyurethane, acrylic resin, acrylic copolymers, polyethers, polyesters, epoxy containing polymers, and mixtures thereof.

[0031] In one example of the disclosure, the solution may include 0.1 wt% to 60 wt% internal extraction material 140. Other concentrations of internal extraction material 140, however, are also contemplated.

Θ032] The internal extraction material may be any material that has a higher refractive index. Suitable formulations include but are not limited to solutions containing at least one of ZrO?., ZnO, and T1O2. For example, a high refractive index formulation could include tens of nano- sized ZrCh, ZnO, and TiCte along with other mixed nanoparticles. The internal extraction material may also include larger quantities of nanoparticles to scatter light. For example, a scatterer formulation in an internal extraction layer may include hundreds of nano-sized ZrCh, ZnO, and TiCh along with mixed nanoparticles,

0G33J With reference to FIG . 2C, a transfer resin 120 is applied to a plastic substrate 1 10. The transfer resin generally may be a curable polymer. Ttie transfer resin may be an ultraviolet sensitive curing polymer, thermal curing polymer or mixture thereof. Any suitable transfer resin may be used including but not limited to polyvinyl alcohol (PV A) including a UV sensitive functional group such as a diazo compound, styrylpyridinium and photo polymerization polymer such as polyester acrylate, epoxy acrylate, urethane aery late, silicone resin acrylate including photo initiator. Also, the transfer resin 12.0 could be ester polymer, acrylic polymer, urethane base polymer, acryl copolymer, urethane base copolymer

(reactivity high molecular compound), silane coupling agent (reactivity small molecular compound) and synthetic rubbers including UV sensitive functional group and thermal sensitive functional group. In the example shown, transfer resin is NOA 63 from Noiand ,

[0034] The transfer resin 120 may be applied to plastic substrate 110 by spraying, dipping, roll-coating or roll-to-roll coating the transfer resin onto the electrode coated donor substrate 105. In one example of the present disclosure, the tran sfer resin is applied to the electrode by applying a thin layer of the transfer resin by spraying, dipping, roll-coating, a roll to roll process, and the like. Other suitable means of applying a surface coating known to those skilled in the art may be used as well. In one example of the disclosure, the transfer resm 120 may be applied to the plastic substrate 110 using a roll-to-roll coating process. The transfer resin 120 may be dried and rinsed once the transfer resm 120 has been applied to the plastic substrate 110. Θ035] The transfer resin 120 thickness is not limited. A sufficient amount of the transfer resin material should he applied to the plastic substrate 110 to provide a thickness suitable for laminating with internal extraction material 140. In one example, the transfer resin 120 may be at least 50 μηι thick. Application methods may be repeated to form thicker transfer resin 120 coatings if needed. A solution may be prepared by dissolving the transfer resin composition in one or more solvents. The transfer resin composition may then be applied to the plastic substrate 110 surface. The solvent(s) may be removed by evaporating or drying the transfer resin composition resulting in the transfer resin 120. it may also be possible to prepare a solution of monomers that may be polymerized to form the transfer resin 120. The monomer solution may then be used to coat the plastic substrate 110 surface. Polymerization of the monomer solutions may occur by applying heat and/or light to the monomer solution.

[0036] The transfer resin material is generally film fonning and able to sufficiently adhere to the plastic substrate 110 during lamination, as discussed below. The transfer resin material may also be a thermoplastic or a thermosetting polymer. In some examples of the present disclosure, the transfer resin coating may be ultraviolet sensitive such that the resin material may cure when exposed to ultraviolet light. For example, the photopolymer may be capable of absorbing light in a wavelength in the range from 180 nm to 500 nm. The photopolymer may be capable of absorbing light in a wavelength in the range from 320 nm to 400 nm.

[0037] In one example of the disclosure, transfer resin material may include a photopolymer, in particular an ultraviolet sensitive photopolymer. The transfer resin material may include other polymers in addition to other polymers. Alternatively, the transfer resin material may consist essentially of a photopolymer. In other examples of the disclosure, the transfer resin material may include a polymer binder and a photoinitiator. Hie photoinitiator may be ultraviolet light sensitive.

[0038] The photopolymer may include for example a polymer having diazo functional groups or styryl functional groups. The photopolymer may include a styryl pyridinium or a styryl pyridinium derivative. The photopolymer may also include poly(vinyl pyridine). The photopolymer may also be a polyvinyl alcohol based photopolymer.

Θ039] The transfer resin material in transfer resin 120 may include a polymer binder and a photoinitiator. Suitable examples of the polymer binder in the transfer resin material may include, but are not limited to, silicone resins, epoxy resms, poiyallyiate resins, PET modified poiyallyiate resins, polycarbonate resins (PC), cyclic olefins, polyethylene terephthalate resins (PET), polymethylmethacrylate resins (PMMA) and mixtures thereof. In one example of the present disclosure, the polymer hinder may include a polyester acrylate, an epoxy acrylate, a urethane acrylate, a silicone resin acrylate or mixtures thereof.

[0040] After applying the transfer resin to plastic substrate 110, the donor substrate 105 is laminated to the plastic substrate 1 10. The plastic substrate 1 10 may be laminated by a roller, roll to roll process, or other suitable lamination process that contacts plastic substrate 110 to donor substrate 105 as shown to form a layered structure comprising donor substrate coated with an internal extraction material 140 covered by transfer resin 120 and plastic substrate 110.

[0041] With reference to FIG. 5, a roll-to-roll process is schematically shown. There, a laminating assembly 400 includes a first roll 401 and a second roll 402 that define a nip 403 therebetween. The internal extraction material coated donor substrate 105 is routed over a first roll 401 and plastic substrate 110 containing the transfer resin 120 is routed over second roll 402. The materials are respectively routed such that the internal extraction material 140 on donor substrate 105 contacts transfer resin 120 on plastic substrate 110 to laminate the plastic substrate to internal extraction material via transfer resin as they pass through nip 403. in the example shown, donor substrate 105 may be a glass substrate. One or more support rollers 404 may be provided to support donor substrate 105 as it is carried to and from nip 403. It will be understood that other means of supporting and transporting a glass substrate including various conveyors or tables may be used.

[0042] Suitable polymeric materials for the plastic substrate 110 include, but are not limited to polyethylene terephthalate (PET), poly methylacrylate (PMA), polymethyl methacrylate (PMMA), polyacrylate copolymer, polyurethane (PU), polyurethane copolymer, cellulose acetate, polystyrene, polystyrene copolymer, polyimide (PI) and mixtures thereof. In the example shown, a PET substrate is used.

[0043] The thickness of the plastic substrate 110 is not particularly limited. For example, the plastic substrate 1 10 thickness may be 300 μτη or less, more preferably 200 μηι or less, and e ven more preferably 100 μιη or less. In some examples of the disclosure, the plastic substrate 1 10 thickness may range from 100 urn to 50 urn. In some examples of the disclosure, the plastic substrate 1 10 thickness may range from 10 μηι to 50 μηι.

[0044] In some examples of the disclosure, the plastic substrate 1 10 is flexible. Polymeric materials that are generally transparent as well as flexible may be used to form the plastic substrate 110. A transparent flexible plastic substrate 110 may be particularly useful for OLED lighting applications or touch screen displays such that light generated by the OLED may pass through the OLED. In one example of the disclosure, polyethylene terephthalate is used to form the plastic substrate 1 10. The polyethylene terephthalate plastic substrate 110 may be used to form the internal extraction film 100.

[0045] With reference to FIG. 2D, a curing step is shown. Depending on the type of polymer used in internal extraction layer 130, heat, light, or a combination thereof may be used to cure the layered substrate. To that end, a suitable curing assembly, generally indicated at 200, is provided with at least one of a heat and light source, 212 to perform curing. In the example show n , an ultraviolet light source is used within curing assembly 200. The internal extraction layer 130 may cure i.e., cross-link, upon exposure to the ultraviolet light source. Hie type of light source and level of penetration may be selected according to the resm material. In the example shown, an ultraviolet light source was used to irradiate at 365 nm. This example was for a PET material and should not be considered limiting. Curing may be performed for a time period based on the type of resin selected. Hie time period is not limiting in this regard. In the example shown, a PET resin was used and curing occurred at room temperature for a time period of about 10 minutes.

Θ046] After curing, transfer resin 120 is transferred to the plastic substrate 110 embedding the patterned nanowires within transfer resin 120. With reference to FIGS. 2E and 2F, the donor substrate 105 is removed leaving a layered structure comprising plastic substrate 110 and transfer resin with an embedded pattern of nanowire electrodes therein to form a patterned electrode as schematically depicted in FIG. 1.

[0047] FIG. 3 shows an image of an internal extraction film 100 formed according to the disclosure. On the left side of FIG. 3, the internal extraction layer 130 on a glass substrate is shown before the transfer process has occurred. The right side image shows the internal extraction layer after the transfer process and with the donor substrate removed to form an internal extraction film 100. The internal extraction film 100 shown has a rectangular configuration, but it will be understood that any configuration may be manufactured according to the examples described herein.

[0048] With reference to FIG. 4, a sample of a spin-coated internal extraction layer (sample a) is compared to an internal extraction layer (sample b) fabricated using a transfer process according to the examples described herein using atomic force microscopy (AFM). A visual comparison of the two images shows improved light extraction in sample b. In addition, the surface roughness improved with the transfer process (sample b) sho wing an AFM of less than 2.0nm compared to less than 1 0 nm in the spin-coated layer (sample a).

[0049] It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated.

Definitions

[0050] It is to be understood that the terminology used herein is for the purpose of describing particular examples only and is not intended to be limiting. As used in the specification and in the claims, the term "comprising" can include the aspects "consisting of and "consisting essentially of." Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In this specification and in the claims which follow, reference will be made to a number of terms which shall be defined herein.

[0051] As used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural equivalents unless the context clearly dictates otherwise. Thus, for example, reference to "a polycarbonate polymer" includes mixtures of two or more polycarbonate polymers.

[0052] As used herein, the term "combination" is inclusive of blends, mixtures, alloys, reaction products, and the like.

[0053] Ranges can be expressed herein as from one value (first value) to another value (second value). When such a range is expressed, the range includes in some aspects one or both of the first value and the second value. Similarly, when values are expressed as approximations, by use of the antecedent 'about,' it will be understood that the particular value forms another example. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as "about" that particular value in addition to the value itself. For example, if the value "10" is disclosed, then "about 10" is also disclosed. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0054] As used herein, the terms "about" and "at or about" mean that the amount or value in question can be the designated value, approximately the designated value, or about the same as the designated value. It is generally understood, as used herein, that it is the nominal value indicated ±5% variation unless otherwise indicated or inferred. The term is intended to convey that similar values promote equivalent results or effects recited in the claims. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but can be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. In general, an amount, size, formulation, parameter or other quantity or characteristic is "about" or "approximate" whether or not expressly stated to be such. It is understood that where "about" is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless specifically stated otherwise.

[0055] Disclosed are the components to be used to prepare the compositions of the disclosure as well as the compositions themselves to be used within the methods disclosed herein.

These and other materials are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these materials are disclosed that while specific reference of each various individual and collective combinations and permutation of these compounds cannot be explicitly disclosed, each is specifically contemplated and described herein. For example, if a particular compound is disclosed and discussed and a number of modifications that can be made to a number of molecules including the compounds are discussed, specifically contemplated is each and every combination and permutation of the compound and the modifications that are possible unless specifically indicated to the contrary. Thus, if a class of molecules A, B, and C are disclosed as well as a class of molecules D, E, and F and an example of a combination molecule, A-D is disclosed, then even if each is not individually recited each is individually and collectively contemplated meaning combinations, A-E, A-F, B-D, B-E, B-F, C-D, C-E, and C-F are considered disclosed. Likewise, any subset or combination of these is also disclosed. Thus, for example, the sub-group of A-E, B-F, and C- E would be considered disclosed. This concept applies to all examples of this application including, but not limited to, steps in methods of making and using the compositions of the disclosure. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific example or combination of examples of the methods of the disclosure.

[0056] As used herein, the term "light" means electromagnetic radiation including ultraviolet, visible or infrared radiation. [0057] As used herein, the term "photopolymer" refers to a polymeric composition that undergoes polymerization, cross-linking, any hardening or curing reactions or otherwise undergoes structural and property changes upon exposure to light.

[0058] As used herein, the term "photoinitiator" refers to a composition that generates a reactive species such as free radicals, cations, ions, when exposed to radiation (UV or visible).

[0059] As used herein, the term "transparent" means that the level of transmittance for a disclosed composition is greater than 50%. In some aspects, the transmittance can be at least 60%, 70%, 80%, 85%, 90%, or 95%, or any range of transmittance values derived from the above exemplified values. In the definition of "transparent," the term "transmittance" refers to the amount of incident light that passes through a sample measured in accordance with ASTM D 1003 at a thickness of 3.2 millimeters.

[0060] Unless otherwise stated to the contrary herein, all test standards are the most recent standard in effect at the time of filing this application.

[0061] EXAMPLES

[0062] Example 1. A process for fabricating an internal extraction film on a substrate, the process comprising: A process for fabricating an internal extraction film on a substrate, the process comprising: (a) providing a substrate as a donor substrate; (b) treating the donor substrate with a photosensitized oxide process; (c) coating an internal extraction layer on the treated donor substrate; (d) applying a transfer resin to the internal extraction layer; (e) laminating the transfer resin with a plastic substrate by roller; (f) curing the transfer resin; and (g) detaching the donor substrate.

[0063] Example 2. The process of example 1, wherein the substrate is hydrophobic.

[0064] Example 3. The process of any of the preceding examples, wherein the substrate is glass.

[0065] Example 4. The process of any one of the preceding examples, wherein the photosensitized oxide process is an ultraviolet ozone process.

[0066] Example 5. The process of any one of the preceding examples, wherein the step of coating an internal extraction layer includes preparing a high refractive index formulation containing tens of at least one of a ZrCh, ZnO and TiCh nanocrystal.

[0067] Example 6. The process of any one of the preceding examples, wherein the step of coating an internal extraction layer includes preparing a scatterer formulation containing hundreds of at least one of a ZrCh, ZnO and TiCh nanocrystal. [0068] Example 7. The process of any of the preceding examples, wherein the transfer resin includes at least one of a ultraviolet and thermal sensitive polymer.

[0069] Example 8. The process of any one of the preceding examples, wherein the transfer resin is a polyvinyl alcohol including at least one of a diazo compound, styrylpyridinium, and photo polymerization polymer.

[0070] Example 9. The process of example 8, wherein the polymerization polymer is at least one of a polyester acrylate, epoxy acrylate, urethane acrylate, silicone resin acrylate including photo initiator. Also, that resin could be ester polymer, acrylic polymer, urethane base polymer, acryl copolymer, urethane base copolymer, silane coupling agent and synthetic rubbers including ultraviolet sensitive functional group and thermal sensitive functional group.

[0071] Example 10. The process of any one of the preceding examples, wherein the donor substrate is at least one of glass, poly ethylene terephthalate, poly methyl acrylate, poly methyl methacrylate, poly acrylate copolymer, polyurethane, polyurethane co polymer, cellulose acetate, polystyrene, polystyrene copolymer, poly imide.

[0072] Example 11. The process of any one of the preceding examples, wherein the step of laminating includes applying the transfer resin to the internal extraction material with a roll- to-roll process.

[0073] Example 12. The process of any one of the preceding examples, wherein the step of coating the internal extraction layer includes at least one of spin coating, mayer bar coating, slot die coating, screen printing, and inkjet printing.

[0074] Example 13. The process of any one of the preceding examples further comprising a step of depositing an electrode on the internal extraction layer before the lamination step.

[0075] Example 14. The process of example 13, wherein the electrode includes at least one of an ITO, ZnO:AL, AZO, Ag, Au, and Pt nanowire.

[0076] Example 15. The process of any one of the preceding examples further comprising depositing at least one of a smoothing layer and a planarization layer before coating the donor substrate with the internal extraction material.

[0077] Example 16. The process of any one of the preceding examples, wherein the internal extraction material layer exhibits an atomic force microscopy less than 20nm.

[0078] Example 17. The process of any one of the preceding examples, wherein the treatment step is performed until a contact angle falls for the donor substrate falls within a range of about 85 to about 92 degrees. [0079] Example 18. The process of example 17, wherein the treatment step includes applying an ultraviolet ozone process for a time period, wherein the time period is in the range of about 30 to about 60 seconds.

[0080] Example 19. An OLED comprising: an internal extraction film prepared by the process of the preceding examples.

[0081] Example 20. The OLED according to example 19, wherein the OLED comprises an improved luminance or power efficiency as compared to a substantially similar OLED that includes the same substrate as the donor substrate but that does not include the internal extraction layer.

[0082] Example 21. The OLED according to example 20, wherein the luminance or power efficiency is at least 10% improved, or at least 20% improved, or at least 30% improved, as compared to a substantially similar OLED that includes the same substrate as the donor substrate but that does not include the internal extraction layer.

[0083] Example 22. A flexible electronic comprising: an internal extraction film prepared by the process of the preceding examples.

[0084] Example 23. A touch display comprising: an internal extraction film prepared by the process of the preceding examples.

[0085] Example 24. An internal extraction film prepared by a process comprising: (a) providing a substrate as a donor substrate; (b) treating the donor substrate to achieve a contact angle from about 85 to about 92 degrees; (c) coating an internal extraction layer on the treated donor substrate; (d) applying a transfer resin to the internal extraction layer; (e) laminating the transfer resin with a plastic substrate by roller; (f) curing the transfer resin; and (g) detaching the donor substrate.

[0086] Example 25. The internal extraction film prepared by the process of example 24, wherein the treating is performed by exposing the donor substrate to ultraviolet ozone.

[0087] Example 26. The internal extraction film prepared by the process of example 25, wherein the step of exposing is performed for a time period, wherein the time period is in a range of about 30 to about 60 seconds.

EXAMPLES

[0088] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices and/or methods claimed herein are made and evaluated, and are intended to be purely exemplary and are not intended to limit the disclosure. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure is at or near atmospheric. Unless indicated otherwise, percentages referring to composition are in terms of wt%.

[0089] There are numerous variations and combinations of reaction conditions, e.g., component concentrations, desired solvents, solvent mixtures, temperatures, pressures and other reaction ranges and conditions that can be used to optimize the product purity and yield obtained from the described process. Only reasonable and routine experimentation will be required to optimize such process conditions.

[0090] An internal extraction layer (IEL) was applied into an OLED device, and performance (luminance and power efficiency) was compared to an OLED device having only a glass substrate. Results are provided in Table 1 :

Table 1. OLED Device Evaluation

[0091] As is evident from the data, both luminance and power efficiency was improved for the IEL-based OLED as compared to the glass substrate-based OLED. Thus, in some aspects of the disclosure, an OLED including an internal extraction layer formed as described herein has an improved luminance and/or power efficiency as compared to a substantially similar OLED that does not include an internal extraction layer.

[0092] Method examples described herein can be machine or computer-implemented at least in part. Some examples can include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device to perform methods as described in the above examples. An implementation of such methods can include code, such as microcode, assembly language code, a higher-level language code, or the like. Such code can include computer readable instructions for performing various methods. The code may form portions of computer program products. Further, in an example, the code can be tangibly stored on one or more volatile, non-transitory, or nonvolatile tangible computer-readable media, such as during execution or at other times.

Examples of these tangible computer-readable media can include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memories (RAMs), read only memories (ROMs), and the like.

[0093] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other aspects can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R.

§ 1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed aspect. Thus, the following claims are hereby incorporated into the Detailed Description as examples or aspects, with each claim standing on its own as a separate aspect, and it is contemplated that such aspects can be combined with each other in various combinations or permutations. The scope of the disclosure should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

CLAIMS We claim:

1. A process for fabricating an internal extraction film on a substrate, the process comprising:

(a) providing a substrate as a donor substrate;

(b) treating the donor substrate with a photosensitized oxide process;

(c) coating an internal extraction layer on the treated donor substrate;

(d) applying a transfer resin to the internal extraction layer;

(e) laminating the transfer resin with a plastic substrate by roller;

(f) curing the transfer resin; and

(g) detaching the donor substrate.

2. The process of claim 1, wherein the substrate is hydrophobic.

3. The process of any of the preceding claims, wherein the substrate is glass.

4. The process of any one of the preceding claims, wherein the photosensitized oxide process is an ultraviolet ozone process.

5. The process of any one of the preceding claims, wherein the step of coating an internal extraction layer includes preparing a high refractive index formulation containing tens of at least one of a ZrCh, ZnO and TiCh nanocrystal.

6. The process of any one of the preceding claims, wherein the step of coating an internal extraction layer includes preparing a scatterer formulation containing hundreds of at least one of a ZrCh, ZnO and TiCh nanocrystal.

7. The process of any of the preceding claims, wherein the transfer resin includes at least one of an ultraviolet and thermal sensitive polymer.

8. The process of any one of the preceding claims, wherein the transfer resin is a polyvinyl alcohol including at least one of a diazo compound, styrylpyridinium, and photo polymerization polymer.

9. The process of claim 8, wherein the polymerization polymer is at least one of a polyester acrylate, epoxy acrylate, urethane acrylate, silicone resin acrylate including photo initiator. Also, that resin could be ester polymer, acrylic polymer, urethane base polymer, acryl copolymer, urethane base copolymer, silane coupling agent and synthetic rubbers including ultraviolet sensitive functional group and thermal sensitive functional group.

10. The process of any one of the preceding claims, wherein the donor substrate is at least one of glass, poly ethylene terephthalate, poly methyl acrylate, poly methyl methacrylate, poly acrylate copolymer, polyurethane, polyurethane co polymer, cellulose acetate, polystyrene, polystyrene copolymer, poly imide.

11. The process of any one of the preceding claims, wherein the step of laminating includes applying the transfer resin to the internal extraction layer with a roll-to-roll process.

12. The process of any one of the preceding claims further comprising a step of depositing an electrode on the internal extraction layer before the laminating step, wherein the electrode includes at least one of an ITO, ZnO:AL, AZO, Ag, Au, and Pt nanowire.

13. The process of any one of the preceding claims further comprising depositing at least one of a smoothing layer and a planarization layer before coating the donor substrate with the internal extraction layer.

14. An OLED comprising an internal extraction film prepared by the process of any one of the preceding claims.

15. The OLED according to claim 14, wherein the OLED comprises an improved luminance or power efficiency as compared to a substantially similar OLED that includes the same substrate as the donor substrate but that does not include the internal extraction layer.

16. A flexible electronic comprising an internal extraction film prepared by the process of any one of the preceding claims.

17. A touch screen comprising an internal extraction film prepared by the process of any one of the preceding claims.

18. An internal extraction film prepared by a process comprising:

(a) providing a substrate as a donor substrate;

(b) treating the donor substrate to obtain a contact angle ranging from about 85 to about 92 degrees;

(c) coating an internal extraction layer on the treated donor substrate;

(d) applying a transfer resin to the internal extraction layer;

(e) laminating the transfer resin with a plastic substrate by roller;

(f) curing the transfer resin; and

(g) detaching the donor substrate.

19. The internal extraction film prepared by the process of claim 18, wherein the treating is performed by exposing the donor substrate to ultraviolet ozone.

20. The internal extraction film prepared by the process of claim 19, wherein the step of exposing is performed for a time period, wherein the time period is in a range of about 30 to about 60 seconds.