Organic light emitting device

Abstract

The invention relates to an organic light-emitting device. Embodiments of the disclosed subject matter provide a device comprising one or more organic layers comprising an emissive layer, a first electrode layer disposed on the one or more organic layers, a plurality of nanostructures formed as part of the first electrode layer, a substrate, a second electrode layer disposed on the substrate, the one or more organic layers are disposed on the second electrode layer, and the first electrode layer including the plurality of nanostructures is disposed on the one or more organic layers and within a predetermined threshold distance of the emissive layer.

Description

[0001] This application is a divisional application of an application with an application date of March 12, 2020, application number 202010171740.7, and invention name “Organic Light-Emitting Device”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. patent application serial number 62 / 817,424 filed on March 12, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0004] The present invention relates to nanostructures that increase emissivity and / or outcoupling, improve device stability and / or provide far-field radiation patterns. Background Art

[0005] Optoelectronic devices utilizing organic materials are becoming increasingly popular for a variety of reasons. Many of the materials used to make the devices are relatively inexpensive, so organic optoelectronic devices have the potential to have cost advantages over inorganic devices. In addition, the inherent properties of organic materials (e.g., their flexibility) can make them more suitable for specific applications, such as manufacturing on flexible substrates. Examples of organic optoelectronic devices include organic light emitting diodes / devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, organic materials can have performance advantages over conventional materials. For example, the wavelength of light emitted by the organic emissive layer can generally be easily adjusted with appropriate dopants.

[0006] OLEDs utilize organic thin films that emit light when voltage is applied to the device. OLEDs are becoming an increasingly popular technology for applications such as flat panel displays, lighting, and backlighting. Several OLED materials and configurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and 5,707,745, which are incorporated herein by reference in their entirety.

[0007] One application of phosphorescent emitting molecules is full-color displays. Industry standards for such displays require pixels that are suitable for emitting specific colors (called "saturated" colors). Specifically, these standards require saturated red, green, and blue pixels. Alternatively, OLEDs can be designed to emit white light. In conventional liquid crystal displays, an absorption filter is used to filter the emission from a white backlight to produce red, green, and blue emissions. The same technology can also be used for OLEDs. White OLEDs can be single EML devices or stacked structures. Color can be measured using CIE coordinates well known in the art.

[0008] As used herein, the term "organic" includes polymeric materials and small molecule organic materials that can be used to make organic optoelectronic devices. "Small molecule" refers to any organic material that is not a polymer, and a "small molecule" may actually be quite large. In some cases, a small molecule may include a repeating unit. For example, the use of a long chain alkyl group as a substituent does not remove a molecule from the "small molecule" category. Small molecules can also be incorporated into polymers, for example as a side group on a polymer backbone or as part of a backbone. Small molecules can also serve as the core portion of a dendritic polymer, which consists of a series of chemical shells built on the core portion. The core portion of a dendritic polymer can be a fluorescent or phosphorescent small molecule emitter. A dendritic polymer can be a "small molecule", and all dendritic polymers currently used in the field of OLEDs are considered to be small molecules.

[0009] As used herein, "top" means farthest from the substrate, while "bottom" means closest to the substrate. Where a first layer is described as being "disposed "above" a second layer, the first layer is disposed farther from the substrate. Unless it is specified that the first layer is "in contact with" the second layer, there may be other layers between the first and second layers. For example, a cathode may be described as being "disposed "above" an anode even though various organic layers are present between the cathode and the anode.

[0010] As used herein, "solution processable" means capable of being dissolved, dispersed or transported in and / or deposited from a liquid medium in the form of a solution or suspension.

[0011] When a ligand is believed to directly contribute to the photosensitive property of an emissive material, the ligand may be referred to as "photosensitive." When a ligand is believed not to contribute to the photosensitive property of an emissive material, the ligand may be referred to as "ancillary," but the ancillary ligand may alter the properties of the photosensitive ligand.

[0012] As used herein, and as will be generally understood by one skilled in the art, a first "Highest Occupied Molecular Orbital" (HOMO) or "Lowest Unoccupied Molecular Orbital" (LUMO) energy level is "greater than" or "higher than" a second HOMO or LUMO energy level if the first energy level is closer to the vacuum energy level. Since the ionization potential (IP) is measured as a negative energy relative to the vacuum energy level, a higher HOMO energy level corresponds to an IP with a smaller absolute value (a less negative IP). Similarly, a higher LUMO energy level corresponds to an electron affinity (EA) with a smaller absolute value (a less negative EA). On a conventional energy level diagram with the vacuum energy level at the top, the LUMO energy level of a material is higher than the HOMO energy level of the same material. A "higher" HOMO or LUMO energy level appears closer to the top of this diagram than a "lower" HOMO or LUMO energy level.

[0013] As used herein, and as one skilled in the art would generally understand, a first work function is "greater than" or "higher than" a second work function if the first work function has a higher absolute value. Because work functions are typically measured as negative numbers relative to the vacuum level, this means that a "higher" work function is more negative. On a conventional energy level diagram with the vacuum level at the top, a "higher" work function is illustrated as being farther away from the vacuum level in a downward direction. Thus, the definition of HOMO and LUMO energy levels follows different rules than work functions.

[0014] More details regarding OLEDs and the definitions set forth above can be found in U.S. Patent No. 7,279,704, which is incorporated herein by reference in its entirety. Summary of the invention

[0015] According to one embodiment, an organic light emitting diode / device (OLED) is also provided. The OLED may include an anode, a cathode, and an organic layer disposed between the anode and the cathode. According to one embodiment, the organic light emitting device is incorporated into one or more devices selected from the following: a consumer product, an electronic component module, and / or a lighting panel.

[0016] According to one embodiment, a device may include one or more organic layers having an emission layer, a first electrode layer disposed on the one or more organic layers, a plurality of nanostructures formed as part of the first electrode layer, a substrate, and a second electrode layer, wherein the second electrode layer is disposed on the substrate, the one or more organic layers are disposed on the second electrode layer, and the first electrode layer including the plurality of nanostructures is disposed on the one or more organic layers and within a predetermined threshold distance of the emission layer.

[0017] At least a portion of the first electrode layer may be at least one of: Ag, Al, Au, Ir, Pt, Ni, Cu, W, Ta, Fe, Cr, Mg, Ga, Rh, Ti, Ru, Pd, In, Bi and / or Ca. These may be included in an alloy, mixture and / or stack in a portion of the first electrode layer. The plurality of nanostructures may be nanopores extending through the thickness of the first electrode layer. The device may include a dielectric layer, wherein the dielectric layer is disposed on the first electrode layer including the plurality of nanostructures. The dielectric layer may be one or more of: organic, titanium dioxide, silicon dioxide, silicon nitride, aluminum oxide, zinc oxide, nickel oxide, germanium oxide, lithium fluoride, magnesium fluoride and / or molybdenum oxide.

[0018] The plurality of nanostructures of the device may be nanopores having a predetermined depth less than the thickness of the first electrode layer. The device may include a dielectric layer, wherein the dielectric layer is disposed on the first electrode layer including the plurality of nanostructures. The plurality of nanostructures may be nanopores, wherein one or more of the nanopores penetrates the thickness of the first electrode layer, and other nanopores have a predetermined depth less than the thickness of the first electrode layer. The device may include a dielectric layer, wherein the dielectric layer is disposed on the first electrode layer including the plurality of nanostructures.

[0019] At least a portion of the second electrode layer of the device may be at least one of: Ag, Al, Au, Ir, Pt, Ni, Cu, W, Ta, Fe, Cr, Mg, Ga, Rh, Ti, Ru, Pd, In, Bi, Ca, titanium dioxide, silicon dioxide, silicon nitride, aluminum oxide, zinc oxide, nickel oxide, germanium oxide, lithium fluoride, molybdenum oxide, and / or a transparent conductive oxide. The plurality of nanostructures of the device may include at least one of: a periodic array of holes, a random array of holes, and a quasi-periodic array of holes in the first electrode layer. The plurality of nanostructures may be configured such that resonances generated by electromagnetic modes in the holes are coupled to propagating surface plasmons of the first electrode layer. The plurality of nanostructures may include an array of holes that provides a grating that enables outcoupling of surface plasmons in the form of light.

[0020] The surface plasmon mode of the device can be coupled to a dipole moment within 30° of a plane parallel to the first electrode layer. The surface plasmon mode of the plurality of nanostructures on the first electrode layer can be coupled to a dipole of the emitting layer oriented parallel to the first electrode layer. The surface plasmon mode can be coupled to a dipole moment within 10° of a plane parallel to the first electrode layer.

[0021] The plurality of nanostructures of the device may include a through hole in the first electrode layer, which is surrounded by a concentric ring grating structure. The concentric ring grating structure of the device may provide outcoupling, and the through hole may set the resonance of the electromagnetic mode. The plurality of nanostructures may include at least one through hole in the first electrode layer. The plurality of nanostructures may be etched on the first electrode layer, and the etching depth may be in the range of 1 nm to the thickness of the first electrode layer. The plurality of nanostructures may be at least one of a metal, a semiconductor and / or a dielectric.

[0022] The radius of curvature in the x, y or z direction of the shape of the multiple nanostructures of the device can tune the resonant frequency of the nanostructure. The multiple nanostructures can be arranged in an array arrangement of a periodic array, a quasi-periodic array and / or a non-periodic array to form an electromagnetic mode generated by electromagnetic coupling between individual nanostructures. When the multiple nanostructures of the device are arranged in an array, the spacing can be in the range of 100nm to 1μm. The periodic array can be at least one of the following: a square grid, a hexagonal grid, a triangular grid and / or a one-dimensional grating. The nodes of the grid include individual nanostructures or a group of nanostructures having a predetermined spacing selected from the group consisting of: a square array, a hexagonal array, a quasi-periodic array and a random array. The multiple nanostructures in the non-periodic array can have a random arrangement. The size of each of the multiple nanostructures can be 5nm to 400nm. The refractive index around the first electrode of the device can be adjustable by including liquid crystal or phase change material. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 An organic light emitting device is shown.

[0024] Figure 2 An inverted organic light-emitting device without a separate electron transport layer is demonstrated.

[0025] 3a-3f show exemplary OLED devices having various nanostructures, with or without a dielectric cap layer, according to embodiments of the disclosed subject matter.

[0026] Figure 4 An exemplary nanostructure array and configuration is shown, as represented by the shaded areas, in accordance with one embodiment of the disclosed subject matter.

[0027] Figure 5 An exemplary array of nanostructures illustrating a far-field radiation pattern having linear polarization of the far-field radiation according to one embodiment of the disclosed subject matter.

[0028] Figure 6 In accordance with an embodiment of the disclosed subject matter, a) a periodic, random or quasi-periodic array of holes (hereinafter referred to as Figure 6 a) and b) showing a through hole (hereinafter referred to as a through hole) in a metal film surrounded by a bull's-eye grating structure. Figure 6b). DETAILED DESCRIPTION

[0029] In general, an OLED comprises at least one organic layer disposed between and electrically connected to an anode and a cathode. When an electric current is applied, the anode injects holes and the cathode injects electrons into the organic layer. The injected holes and electrons each migrate toward the oppositely charged electrode. When electrons and holes are localized on the same molecule, an "exciton" is formed, which is a localized electron-hole pair with an excited energy state. When the exciton relaxes through a light emission mechanism, light is emitted. In some cases, the exciton can be localized on an excimer or an excited complex. Non-radiative mechanisms (such as thermal relaxation) may also occur, but are generally considered undesirable.

[0030] The first OLEDs used emissive molecules that emitted light from a singlet state ("fluorescence"), as disclosed, for example, in US Pat. No. 4,769,292, which is incorporated by reference in its entirety. Fluorescence emission typically occurs in a time frame of less than 10 nanoseconds.

[0031] Recently, OLEDs with emissive materials that emit light from triplet states ("phosphorescence") have been demonstrated. Baldo et al., "Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices", Nature, Vol. 395, 151-154, 1998 ("Baldo-I"); and Baldo et al., "Very high-efficiency green organic light-emitting devices based on electrophosphorescence", Appl. Phys. Lett., Vol. 75, Nos. 3, 4-6 (1999) ("Baldo-II"), which are incorporated by reference in their entirety. Phosphorescence is described in more detail in U.S. Pat. No. 7,279,704, Columns 5-6, which is incorporated by reference.

[0032] Figure 1An organic light-emitting device 100 is shown. The figure is not necessarily drawn to scale. The device 100 may include a substrate 110, an anode 115, a hole injection layer 120, a hole transport layer 125, an electron blocking layer 130, an emission layer 135, a hole blocking layer 140, an electron transport layer 145, an electron injection layer 150, a protective layer 155, a cathode 160, and a blocking layer 170. The cathode 160 is a composite cathode having a first conductive layer 162 and a second conductive layer 164. The device 100 can be manufactured by depositing the layers in sequence. The properties and functions of these various layers and example materials are described in more detail in US 7,279,704, columns 6-10, which are incorporated by reference.

[0033] More examples of each of these layers are available. For example, a flexible and transparent substrate-anode combination is disclosed in U.S. Pat. No. 5,844,363, which is incorporated by reference in its entirety. An example of a p-doped hole transport layer is one doped with F at a molar ratio of 50:1. 4 -TCNQ m-MTDATA, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated by reference in its entirety. Examples of luminescent and host materials are disclosed in U.S. Patent No. 6,303,238 to Thompson et al., which is incorporated by reference in its entirety. An example of an n-doped electron transport layer is BPhen doped with Li in a 1:1 molar ratio, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated by reference in its entirety. U.S. Patent Nos. 5,703,436 and 5,707,745, which are incorporated by reference in their entirety, disclose examples of cathodes including composite cathodes having a thin layer of a metal (e.g., Mg:Ag) with an overlying transparent, conductive, sputter-deposited ITO layer. The theory and use of barrier layers are described in more detail in U.S. Patent No. 6,097,147 and U.S. Patent Application Publication No. 2003 / 0230980, which are incorporated by reference in their entirety. Examples of injection layers are provided in U.S. Patent Application Publication No. 2004 / 0174116, which is incorporated by reference in its entirety. A description of protective layers can be found in U.S. Patent Application Publication No. 2004 / 0174116, which is incorporated by reference in its entirety.

[0034] Figure 2An inverted OLED 200 is shown. The device includes a substrate 210, a cathode 215, an emissive layer 220, a hole transport layer 225, and an anode 230. Device 200 can be manufactured by depositing the layers in order. Because the most common OLED configuration has a cathode disposed above the anode, and device 200 has cathode 215 disposed below anode 230, device 200 can be referred to as an "inverted" OLED. Materials similar to those described with respect to device 100 can be used in the corresponding layers of device 200. Figure 2 An example is provided of how some layers may be omitted from the structure of device 100 .

[0035] Figure 1 and 2 The simple layered structures described in are provided by way of non-limiting examples, and it should be understood that embodiments of the present invention may be used in conjunction with various other structures. The specific materials and structures described are exemplary in nature, and other materials and structures may be used. Functional OLEDs may be obtained by combining the various layers described in different ways, or the layers may be omitted entirely based on design, performance, and cost factors. Other layers not specifically described may also be included. Materials other than the specifically described materials may be used. Although many of the examples provided herein describe the various layers as comprising a single material, it should be understood that a combination of materials may be used, such as a mixture of a host and a dopant, or more generally, a mixture. In addition, the layers may have various sublayers. The names given to the various layers herein are not intended to be strictly limiting. For example, in device 200, hole transport layer 225 transports holes and injects holes into emissive layer 220, and may be described as a hole transport layer or a hole injection layer. In one embodiment, the OLED may be described as having an "organic layer" disposed between a cathode and an anode. This organic layer may include a single layer, or may further include, for example, Figure 1 and 2 Multiple layers of said different organic materials.

[0036] Structures and materials not specifically described may also be used, such as OLEDs containing polymeric materials (PLEDs), such as disclosed in U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated by reference in its entirety. By way of another example, an OLED having a single organic layer may be used. OLEDs may be stacked, such as described in U.S. Pat. No. 5,707,745 to Forrest et al., which is incorporated by reference in its entirety. OLED structures may deviate from Figure 1 and 2For example, the substrate may include angled reflective surfaces to improve out-coupling, such as a mesa structure as described in U.S. Pat. No. 6,091,195 to Forrest et al., and / or a pit structure as described in U.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated by reference in their entirety.

[0037] In some embodiments disclosed herein, an emissive layer or material, such as Figure 1-2 The emission layer 135 and the emission layer 220 shown in the figure, respectively, may include quantum dots. Unless explicitly indicated to the contrary or indicated by the circumstances according to the understanding of a person skilled in the art, an "emission layer" or "emission material" as disclosed herein may include an organic emission material and / or an emission material containing quantum dots or an equivalent structure. Such an emission layer may only include a quantum dot material that converts light emitted by a separate emission material or other emitter, or it may also include the separate emission material or other emitter, or it itself may directly emit light by applying an electric current. Similarly, a color-changing layer, a color filter, an up-conversion or down-conversion layer or structure may include a material containing quantum dots, but such a layer may not be considered an "emission layer" as disclosed herein. In general, an "emission layer" or material is an "emission layer" or material that emits initial light, which can be changed by another layer (such as a color filter or other color-changing layer) that does not emit initial light in the device itself, and can also re-emit changed light with different spectral content based on the initial light emitted by the emission layer.

[0038] Unless otherwise specified, any of the layers of the various embodiments may be deposited by any suitable method. For organic layers, preferred methods include thermal evaporation, inkjet (as described in U.S. Pat. Nos. 6,013,982 and 6,087,196, incorporated by reference in their entirety), organic vapor phase deposition (OVPD) (as described in U.S. Pat. No. 6,337,102 to Forrest et al., incorporated by reference in their entirety), and deposition by organic vapor jet printing (OVJP) (as described in U.S. Pat. No. 7,431,968, incorporated by reference in their entirety). Other suitable deposition methods include spin coating and other solution-based processes. Solution-based processes are preferably carried out in nitrogen or an inert atmosphere. For other layers, preferred methods include thermal evaporation. Preferred patterning methods include deposition through a mask, cold welding (as described in U.S. Pat. Nos. 6,294,398 and 6,468,819, which are incorporated by reference in their entirety), and patterning associated with some of the deposition methods such as inkjet and OVJD. Other methods may also be used. The material to be deposited may be modified to make it compatible with a specific deposition method. For example, branched or unbranched substituents such as alkyl and aryl groups, preferably containing at least 3 carbons, may be used in small molecules to enhance their ability to withstand solution processing. Substituents having 20 or more carbons may be used, and 3 to 20 carbons are a preferred range. Materials having asymmetric structures may have better solution processability than materials having symmetric structures because asymmetric materials may have a lower tendency to recrystallize. Dendritic polymer substituents may be used to enhance the ability of small molecules to withstand solution processing.

[0039] The device manufactured according to the embodiment of the present invention may further optionally include a barrier layer. One purpose of the barrier layer is to protect the electrode and the organic layer from exposure to harmful substances in an environment including moisture, steam and / or gas. The barrier layer can be deposited on a substrate, an electrode, under a substrate, an electrode, or beside a substrate, an electrode, or on any other part (including the edge) of the device. The barrier layer may include a single layer or multiple layers. The barrier layer may be formed by various known chemical vapor deposition techniques, and may include a composition having a single phase and a composition having multiple phases. Any suitable material or material combination may be used for the barrier layer. The barrier layer may be combined with an inorganic compound or an organic compound or both. A preferred barrier layer includes a mixture of a polymeric material and a non-polymeric material, as described in U.S. Patent No. 7,968,146, PCT Patent Application No. PCT / US2007 / 023098, and No. PCT / US2009 / 042829, which are incorporated herein by reference in their entirety. In order to be considered a "mixture", the aforementioned polymeric material and non-polymeric material constituting the barrier layer should be deposited under the same reaction conditions and / or deposited simultaneously. The weight ratio of polymeric material to non-polymeric material can be in the range of 95:5 to 5:95. The polymeric material and non-polymeric material can be produced from the same precursor material. In one example, the mixture of polymeric material and non-polymeric material consists essentially of polymeric silicon and inorganic silicon.

[0040] Devices manufactured according to embodiments of the present invention may be incorporated into a wide variety of electronic component modules (or units), which may be incorporated into a variety of electronic products or intermediate components. Examples of electronic products or intermediate components include display screens, lighting devices (such as discrete light source devices or lighting panels), etc. that can be utilized by end-user product manufacturers. The electronic component module may optionally include drive electronics and / or a power supply. Devices manufactured according to embodiments of the present invention may be incorporated into a wide variety of consumer products, which have one or more electronic component modules (or units) incorporated therein. A consumer product comprising an OLED is disclosed, wherein the OLED includes a compound of the present disclosure in an organic layer in the OLED. The consumer product should include any kind of product containing one or more of one or more light sources and / or a certain type of visual display. Some examples of such consumer products include flat panel displays, computer monitors, medical monitors, televisions, billboards, lights for interior or exterior lighting and / or signaling, heads-up displays, fully or partially transparent displays, flexible displays, laser printers, telephones, cellular phones, tablet computers, tablet phones, personal digital assistants (PDAs), wearable devices, laptop computers, digital cameras, video cameras, viewfinders, microdisplays (displays with a diagonal of less than 2 inches), 3-D displays, virtual reality or augmented reality displays, vehicles, video walls comprising multiple displays tiled together, theater or stadium screens, and signage. Various control mechanisms can be used to control devices made according to the present invention, including passive matrices and active matrices. Many of the devices are intended to be used in a temperature range that is comfortable for humans, such as 18C to 30C, and more preferably at room temperature (20-25C), but can be used outside this temperature range (e.g., -40C to 80C).

[0041] The materials and structures described herein can be applied to devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors can employ the materials and structures. More generally, organic devices such as organic transistors can employ the materials and structures.

[0042] In some embodiments, the OLED has one or more features selected from the group consisting of: flexible, rollable, foldable, stretchable, and bendable. In some embodiments, the OLED is transparent or translucent. In some embodiments, the OLED further comprises a layer comprising carbon nanotubes.

[0043] In some embodiments, the OLED further comprises a layer comprising a delayed fluorescent emitter. In some embodiments, the OLED comprises an RGB pixel arrangement or a white plus color filter pixel arrangement. In some embodiments, the OLED is a mobile device, a handheld device, or a wearable device. In some embodiments, the OLED is a display panel having a diagonal of less than 10 inches or an area of ​​less than 50 square inches. In some embodiments, the OLED is a display panel having a diagonal of at least 10 inches or an area of ​​at least 50 square inches. In some embodiments, the OLED is a lighting panel.

[0044] In some embodiments of the emission region, the emission region further comprises a body.

[0045] In some embodiments, the compound can be an emissive dopant. In some embodiments, the compound can generate emission via phosphorescence, fluorescence, thermally activated delayed fluorescence (ie, TADF, also known as E-type delayed fluorescence), triplet-triplet annihilation, or a combination of these processes.

[0046] The OLEDs disclosed herein may be incorporated into one or more of consumer products, electronic component modules, and lighting panels.The organic layer may be an emissive layer, and the compound may be an emissive dopant in some embodiments, while the compound may be a non-emissive dopant in other embodiments.

[0047] The organic layer may also include a host. In some embodiments, two or more hosts are preferred. In some embodiments, the host used may be a) bipolar, b) electron transport, c) hole transport, or d) wide bandgap material that plays a small role in charge transport. In some embodiments, the host may include a metal complex. The host may be an inorganic compound.

[0048] Combination with other materials

[0049] The materials described herein as being suitable for use in a particular layer in an organic light-emitting device can be used in combination with a variety of other materials present in the device. For example, the emissive dopants disclosed herein can be used in combination with a wide variety of hosts, transport layers, barrier layers, injection layers, electrodes, and other layers that may be present. The materials described or mentioned below are non-limiting examples of materials that can be used in combination with the compounds disclosed herein, and those skilled in the art can readily consult the literature to identify other materials that can be used in combination.

[0050] Different emissive and non-emissive layers and arrangements disclosed herein may use different materials. Examples of suitable materials are disclosed in U.S. Patent Application Publication No. 2017 / 0229663, which is incorporated by reference in its entirety.

[0051] Conductive dopants:

[0052] The charge transport layer can be doped with a conductivity dopant to substantially change its charge carrier density, which in turn will change its conductivity. The conductivity is increased by generating charge carriers in the matrix material, and depending on the type of dopant, a change in the Fermi level of the semiconductor can also be achieved. The hole transport layer can be doped with a p-type conductivity dopant, and an n-type conductivity dopant is used in the electron transport layer.

[0053] HIL / HTL:

[0054] The hole injection / transport material used in the present invention is not particularly limited, and any compound may be used as long as the compound is generally used as a hole injection / transport material.

[0055] EBL:

[0056] An electron blocking layer (EBL) can be used to reduce the number of electrons and / or excitons that leave the emissive layer. The presence of such a blocking layer in a device can produce substantially higher efficiency and / or longer lifetime than a similar device lacking a blocking layer. In addition, a blocking layer can be used to confine emission to desired areas of the OLED. In some embodiments, the EBL material has a higher LUMO (closer to the vacuum level) and / or a higher triplet energy than the emitter closest to the EBL interface. In some embodiments, the EBL material has a higher LUMO (closer to the vacuum level) and / or a higher triplet energy than one or more of the hosts closest to the EBL interface. In one aspect, the compound used in the EBL contains the same molecule or the same functional group as used in one of the hosts described below.

[0057] main body:

[0058] The light-emitting layer of the organic EL device of the present invention preferably contains at least a metal complex as a light-emitting material, and may contain a host material using the metal complex as a dopant material. Examples of the host material are not particularly limited, and any metal complex or organic compound may be used as long as the triplet energy of the host is greater than the triplet energy of the dopant. Any host material may be used with any dopant as long as the triplet criterion is satisfied.

[0059] HBL:

[0060] A hole blocking layer (HBL) can be used to reduce the number of holes and / or excitons that leave the emissive layer. The presence of such a blocking layer in a device can result in substantially higher efficiency and / or longer lifetime than a similar device lacking a blocking layer. In addition, a blocking layer can be used to confine emission to a desired area of ​​the OLED. In some embodiments, the HBL material has a lower HOMO (further from the vacuum level) and / or a higher triplet energy than the emitter closest to the HBL interface. In some embodiments, the HBL material has a lower HOMO (further from the vacuum level) and / or a higher triplet energy than one or more of the hosts closest to the HBL interface.

[0061] ETL:

[0062] The electron transport layer (ETL) may include a material capable of transporting electrons. The electron transport layer may be intrinsic (undoped) or doped. Doping may be used to enhance conductivity. Examples of ETL materials are not particularly limited, and any metal complex or organic compound may be used as long as it is typically used to transport electrons.

[0063] Charge Generation Layer (CGL)

[0064] In a tandem or stacked OLED, the CGL plays a fundamental role in the performance and is composed of an n-doped layer and a p-doped layer for injecting electrons and holes, respectively. Electrons and holes are supplied by the CGL and electrodes. The electrons and holes consumed in the CGL are refilled by electrons and holes injected from the cathode and anode, respectively; then, the bipolar current gradually reaches a steady state. Typical CGL materials include n- and p-conductivity dopants used in the transport layer.

[0065] Embodiments of the disclosed subject matter provide improved organic light emitting diode (OLED) performance by using nanostructures having one or more different geometric sizes, shapes, materials, and / or lattice symmetries. The nanostructures can enhance emissivity, increase surface plasmon polariton (SPP) mode outcoupling, improve device stability, and / or provide far-field radiation patterns.

[0066] In order to efficiently couple excited state energy into the plasmon mode, the emitter or emitting layer can be placed within a threshold distance of the structure and / or layer that increases the photon state density (as shown in Figures 3a-3f), followed by an enhanced emission rate, known as the Purcell effect. The threshold distance can be the distance at which the total non-radiative decay rate constant is equal to the total radiative decay rate constant, consistent with U.S. Patent No. 9,960,386, the disclosure of which is incorporated herein by reference in its entirety.

[0067] The exemplary devices in Figures 3a-3f show variations of nanostructured cathodes in cross-sectional views. These nanostructures include nanopores that can be etched completely through a metal film (e.g., Figure 3a-3b ), partially penetrate the metal film (e.g. Figure 3c-3d ), or some of the holes may be etched completely through the metal film while other holes are only partially etched (e.g., as shown in Figure 3e-3f 3a-3f show variations where the nanostructure cathode may be capped with a dielectric layer (e.g., as shown in FIG. 3a, FIG. 3c, FIG. 3e), or not capped with a dielectric layer (e.g., as shown in FIG. 3b, 3d, 3f) to match the refractive index beneath the cathode to improve cross-coupling of surface plasmon modes across the thickness of the metal film (e.g., the thickness of the electrode layer). The profile of the holes (i.e., whether the hole edges and / or sidewalls may be perpendicular to the surface of the film or whether the sidewalls of the holes have a radius of curvature) may be used to tune the properties of the nanostructure array.

[0068] Nanostructures can be made of metals, dielectrics, or some combination of these. Using composites (e.g., metals and dielectrics) can provide flexibility in device design because the resonant frequency of the local mode can be tuned and / or selected by the composite used. For each of these materials, the local electromagnetic mode can be tuned. Typical metals that can be used include, but are not limited to: Ag, Al, Au, Ir, Pt, Ni, Cu, W, Ta, Fe, Cr, Mg, Ga, Rh, Ti, Ru, Pd, In, Bi, and / or Ca. In some embodiments, stacks and / or alloys of these materials can be used. The dielectrics used may include, but are not limited to: organic materials, titanium dioxide, silicon dioxide, silicon nitride, aluminum oxide, zinc oxide, nickel oxide, germanium oxide, lithium fluoride, magnesium fluoride, and / or molybdenum oxide.

[0069] The local electromagnetic resonance of a nanostructure or a portion of a nanostructure can be tuned by the shape of the nanostructure. The shape can include any cylindrical, spherical and / or cubic. Or any shape with single or multiple local resonances. The radius of curvature of the edges and / or corners in the faceted nanostructure can be used to tune the resonant frequency of the nanostructure. Some examples of multiple local resonance shapes can include ellipses and rectangles, which support multiple modes with different frequencies induced by the asymmetry of the nanostructure. For example, different lengths and / or widths of rectangular nanostructures can produce two different resonant frequencies. These multiple frequency nanostructures can provide enhanced outcoupling for multi-wavelength or white light emitting OLEDs.

[0070] That is, embodiments of the disclosed subject matter as shown in Figures 3a-3f may include a device having one or more organic layers, which may include an emissive layer. A first electrode layer may be disposed on the one or more organic layers, and a plurality of nanostructures may be formed as part of the first electrode layer. The device may include a substrate and a second electrode layer, wherein the second electrode layer may be disposed on the substrate, the one or more organic layers may be disposed on the second electrode layer, and the first electrode layer including the plurality of nanostructures is disposed on the one or more organic layers and within a predetermined threshold distance of the emissive layer.

[0071] As shown in FIG. 3b, the plurality of nanostructures may be nanopores that penetrate the thickness of the first electrode layer. As shown in FIG. 3a, the device may include a dielectric layer, wherein the dielectric layer is disposed on the first electrode layer including the plurality of nanostructures. The dielectric layer may be one of the following: organic matter, titanium dioxide, silicon dioxide, silicon nitride, aluminum oxide, zinc oxide, nickel oxide, germanium oxide, lithium fluoride, magnesium fluoride and / or molybdenum oxide. FIG. 3d shows that the plurality of nanostructures may be nanopores having a predetermined depth less than the thickness of the first electrode layer. FIG. 3c shows that the device includes a dielectric layer, wherein the dielectric layer may be disposed on the first electrode layer including the plurality of nanostructures. FIG. 3f shows that the plurality of nanostructures may be nanopores, wherein one or more of the nanopores penetrate the thickness of the first electrode layer, and the other nanopores have a predetermined depth less than the thickness of the first electrode layer. FIG. 3e shows that the device may include a dielectric layer, wherein the dielectric layer may be disposed on the first electrode layer including the plurality of nanostructures.

[0072] In addition to the local resonance of individual nanostructures, arranging the nanostructures into periodic, quasi-periodic or non-periodic arrays can provide electromagnetic modes generated by electromagnetic coupling between individual nanostructures. Periodic arrays can provide mixing between local modes of the nanostructures and diffraction modes generated by the periodic arrangement. When arranged in an array, the spacing can range from 100 nm to 1 μm. Examples of various periodic arrays ranging from simple square grids to more complex geometries such as hexagonal grids are shown in Figure 4 Each node of the mesh may include an individual nanostructure or a group of nanostructures having different periodicity and / or spacing, including but not limited to a square array, a hexagonal array, a quasi-periodic array, or a random array. Such an arrangement provides a mesh-of-a-mesh, where the primary and secondary meshes do not necessarily have the same geometry.

[0073] Each nanopore in the nanostructured cathode can be arranged in a specific geometric structure, e.g. Figure 4(top view), which may include periodic arrays, quasi-periodic arrays, or non-periodic arrays, including random arrangements. Each node of the grid may include an individual nanopore or a group of nanopores, which have different period numbers and / or spacings, including but not limited to square arrays, hexagonal arrays, quasi-periodic arrays, or random arrays. This can provide a grid within a grid, where the primary and secondary grids do not necessarily have the same geometry.

[0074] Complex lattice geometries can provide exotic band dispersions, such as planar bands, which can provide enhanced light-matter interactions, or bands with positive or negative curvature. Changing the fill factor of the grating along any dimension (e.g., along the x, y, or z directions) can be used to tune the mixed mode frequency. Quasi-periodic arrangements of nanostructures can provide broadband optical response or multi-wavelength. This arrangement can be desirable for use in white light OLEDs and / or multi-wavelength emitters. Random arrangements of nanostructures can be used when using simpler and more scalable manufacturing methods, such as spin coating. Such random or non-periodic arrays of nanostructures can be achieved as follows: by depositing a metal film under growth conditions that are conducive to metal dewetting to form islands that can act as nanostructures.

[0075] In general, the size of the nanostructures can be used to tune the resonant plasma frequency, where, in general, larger nanostructures or nanostructure portions resonate at lower energies than smaller nanostructures or smaller nanostructure portions, all other things being equal. Typical nanostructure sizes can have a minimum dimension in the range of 5 nm to 400 nm. The refractive index of the nanostructure or nanostructure portion itself and its surroundings can be used to tune the resonant mode frequency. When the nanostructures are included in a lattice, the overall optical response of the array can be made reconfigurable by using a medium whose refractive index (dielectric constant) can be tuned on demand via external stimuli. For example, liquid crystals or phase change materials can be used to provide tuning.

[0076] When the same nanostructures are used for Purcell enhancement and outcoupling, the phase front of the emission wave from the OLED can be reduced and / or eliminated. This can be achieved by having subwavelength-sized nanostructures impart different phases to the light output from the OLED. By applying the Huygens principle, each of these nanostructures can be configured to act as a point scatterer, and the overall phase induced by the nanostructures can be controlled by their shape and refractive index. For example, a nanostructure such as Figure 5 OLEDs with more than linearly polarized output can be configured using the nanostructure patterns shown in . OLEDs with more complex phase fronts, such as light with a central singularity or circular polarization, can be configured through the arrangement of nanostructures. As discussed above, the structures can be tunable for different wavelengths or beams by controlling the refractive index of the surrounding medium using materials such as liquid crystals or phase change materials.

[0077] The phase of the emission wave from the OLED can be adjusted by arranging and / or forming sub-wavelength sized nanoholes to impart different phases to the light generated by the OLED, as described in detail above and Figure 5 as shown in .

[0078] Surface plasmon polaritons (SPPs) can couple efficiently to vertically oriented dipoles due to their corresponding electric field orientation. Horizontal dipoles generally do not couple efficiently to surface plasmons, which can limit SPP-based emissivity-enhancing arrangements of vertically oriented dipoles. At least two different plasmon structures can overcome this limitation. Figure 6 As shown in , these structures may include: periodic, random, or quasi-periodic arrays of holes in the metal film ( Figure 6 a); or a through hole in a metal film surrounded by a bullseye grating structure ( Figure 6 b) These structures can rely on resonances generated by electromagnetic modes in the through-holes that couple to propagating surface plasmons of the film on the top surface. Figure 6 In the case of (a), the array may be a grating that outcouples surface plasmon energy in the form of light. Figure 6 In b, the bullseye grating provides the outcoupling function, while the vias set the resonance of the electromagnetic mode.

[0079] That is, Figures 3a-6b show embodiments of devices that include an emission layer, and a first electrode layer disposed on one or more organic layers. A plurality of nanostructures may be formed as part of the first electrode layer. The device may include a substrate and a second electrode layer. The second electrode layer may be disposed on the substrate, one or more organic layers are disposed on the second electrode layer, and the first electrode layer including the plurality of nanostructures is disposed on the one or more organic layers and within a predetermined threshold distance of the emission layer. At least a portion of the first electrode layer may be at least one of: Ag, Al, Au, Ir, Pt, Ni, Cu, W, Ta, Fe, Cr, Mg, Ga, Rh, Ti, Ru, Pd, In, Bi, and / or Ca. These may be included in an alloy, mixture, and / or stack in a portion of the first electrode layer. At least a portion of the second electrode layer is at least one selected from the group consisting of: Ag, Al, Au, Ir, Pt, Ni, Cu, W, Ta, Fe, Cr, Mg, Ga, Rh, Ti, Ru, Pd, In, Bi, Ca, titanium dioxide, silicon dioxide, silicon nitride, aluminum oxide, zinc oxide, nickel oxide, germanium oxide, lithium fluoride, molybdenum oxide and / or a transparent conductive oxide.

[0080] The plurality of nanostructures of the device may include at least one of a periodic array of holes, a random array of holes, and a quasi-periodic array of holes in the first electrode layer. The plurality of nanostructures may be configured such that resonances generated by electromagnetic modes in the holes couple to propagating surface plasmons of the first electrode layer.

[0081] The plurality of nanostructures of the device may include an array of holes that provide a grating that enables outcoupling of surface plasmon energy in the form of light. The surface plasmon mode is coupled to a dipole moment within 30° of a plane parallel to the first electrode layer. The surface plasmon mode of the plurality of nanostructures on the first electrode layer may be coupled to a dipole of the emitting layer oriented parallel to the first electrode layer. In some embodiments, the surface plasmon mode may be coupled to a dipole moment that is within 10° of a plane parallel to the first electrode layer.

[0082] The plurality of nanostructures on the device may include a through hole in the first electrode layer, which is surrounded by a concentric ring grating structure. The concentric ring grating structure may provide outcoupling, and the through hole may set the resonance of the electromagnetic mode.

[0083] In some embodiments, the plurality of nanostructures of the device may include at least one through hole in the first electrode layer. The plurality of nanostructures may be etched on the first electrode layer, and the etching depth ranges from 1 nm to the thickness of the first electrode layer. In some embodiments, the plurality of nanostructures comprises at least one selected from the group consisting of: a metal, a semiconductor, and a dielectric. The radius of curvature in the x, y, or z direction of the shape of the plurality of nanostructures of the device may tune the resonant frequency of the nanostructures.

[0084] A plurality of nanostructures are arranged in an array arrangement which may be selected from a group consisting of: a periodic array, a quasi-periodic array, and a non-periodic array to form an electromagnetic mode generated by electromagnetic coupling between individual nanostructures. When a plurality of nanostructures are arranged in an array, the spacing may be in the range of 100 nm to 1 μm. The periodic array may be a square grid, a hexagonal grid, a triangular grid, and / or a one-dimensional grating. The nodes of the grid may include an individual nanostructure or a group of nanostructures having a predetermined spacing of a square array, a hexagonal array, a quasi-periodic array, and / or a random array. A plurality of nanostructures in a non-periodic array may have a random arrangement. In some embodiments, the size of each of the plurality of nanostructures may be 5 nm to 400 nm. In some embodiments, the refractive index around the first electrode of the device may be adjustable by including a liquid crystal or a phase change material.

[0085] It should be understood that the various embodiments described herein are by way of example only, and are not intended to limit the scope of the present invention. For example, other materials and structures may be used to replace many materials and structures described herein without departing from the spirit of the present invention. The present invention as required may therefore include variations of specific examples and preferred embodiments described herein, as will be apparent to those skilled in the art. It should be understood that the various theories about why the present invention works are not intended to be restrictive.

Claims

1. A device comprising: one or more organic layers including an emissive layer; a first electrode layer disposed on the one or more organic layers; a plurality of nanostructures formed as part of the first electrode layer; substrate; and The second electrode layer, wherein the second electrode layer is disposed on the substrate, the one or more organic layers are disposed on the second electrode layer, and the first electrode layer including the plurality of nanostructures is disposed on the one or more organic layers and within a predetermined threshold distance of the emissive layer, wherein the threshold distance is a distance at which a total non-radiative decay rate constant is equal to a total radiative decay rate constant; and The plurality of nanostructures are nanopores in the first electrode layer, and the plurality of nanopores only partially penetrate the thickness of the first electrode layer.

2. The device of claim 1 , wherein at least a portion of the first electrode layer is at least one element selected from the group consisting of Ag, Al, Au, Ir, Pt, Ni, Cu, W, Ta, Fe, Cr, Mg, Ga, Rh, Ti, Ru, Pd, In, Bi, and Ca.

3. The device of claim 2, wherein the at least one selected element is included in at least one of: an alloy, a mixture, and a stack of at least a portion of the first electrode layer. The device of claim 1 , wherein the plurality of nanostructures extend through the thickness of the first electrode layer.

5. The device according to claim 4, further comprising: Dielectric layer, The dielectric layer is disposed on the first electrode layer including the plurality of nanostructures.

6. The device of claim 5, wherein the dielectric layer is selected from the group consisting of organic matter, titanium dioxide, silicon dioxide, silicon nitride, aluminum oxide, zinc oxide, nickel oxide, germanium oxide, lithium fluoride, magnesium fluoride, and molybdenum oxide.

7. The device of claim 1, further comprising: Dielectric layer, The dielectric layer is disposed on the first electrode layer including the plurality of nanostructures. 8 . The device of claim 1 , wherein other nanopores partially penetrating the thickness of the first electrode layer have a predetermined depth that is less than the thickness of the first electrode layer.

9. The device of claim 8, further comprising: a dielectric layer, The dielectric layer is disposed on the first electrode layer including the plurality of nanostructures.

10. The device of claim 1, wherein surface plasmon modes of the plurality of nanostructures that are part of the first electrode layer couple to dipoles of the emitting layer that are preferentially oriented parallel to the first electrode layer.

11. The device of claim 1, wherein the plurality of nanostructures comprises through-holes in the first electrode layer surrounded by concentric ring grating structures.

12. The device of claim 1, wherein the plurality of nanostructures comprises at least one selected from the group consisting of: a metal, a semiconductor, and a dielectric.

13. The device of claim 1, wherein the plurality of nanostructures are disposed in an array arrangement selected from the group consisting of: a periodic array, a quasi-periodic array, and a non-periodic array to form an electromagnetic mode generated by electromagnetic coupling between individual nanostructures.

14. The device of claim 13, wherein the periodic array is selected from the group consisting of: a square grid, a hexagonal grid, a triangular grid, and a one-dimensional grating.

15. The device of any one of claims 1-14, wherein each of the plurality of nanostructures has a size of 5 nm to 400 nm.

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