Deep highest occupied molecular orbital (HOMO) emitter device structures

Abstract

The invention relates to a deep highest occupied molecular orbital (HOMO) emitter device structure. Embodiments of the disclosed subject matter provide an organic light emitting diode (OLED) having an anode, a cathode, an emissive layer disposed between the anode and the cathode, and a hole blocking layer disposed between the emissive layer and the cathode. The emissive layer may include a phosphorescent dopant, wherein the phosphorescent dopant has emission with a peak maximum wavelength greater than or equal to 600 nm in a 0.5% doped poly (methyl methacrylate) PMMA thin film at room temperature. The highest occupied molecular orbital HOMO energy of the phosphorescent dopant may be less than or equal to-5.1 eV, and the HOMO energy of the hole blocking layer is at least 0.1 eV lower than the HOMO energy of the phosphorescent dopant.

Description

[0001] This application is a divisional application of an application filed on October 23, 2019, with application number 201911012373.X, and invention name “Deep Highest Occupied Molecular Orbital (HOMO) Emitter Device Structure”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Patent Application No. 62 / 749,290, filed on October 23, 2018, the entire contents of which are incorporated herein by reference. Technical Field

[0004] The present invention relates to compounds for use as emitters; and devices including the same, such as organic light emitting diodes. 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] Embodiments of the disclosed subject matter may provide an organic light emitting diode (OLED) having an anode, a cathode, an emission layer disposed between the anode and the cathode, and a hole blocking layer disposed between the emission layer and the cathode. The emission layer may include a phosphorescent dopant. The phosphorescent dopant has an emission with a peak maximum wavelength greater than or equal to 600 nm in a 0.5% doped poly(methyl methacrylate) (PMMA) film at room temperature. The highest occupied molecular orbital (HOMO) energy of the phosphorescent dopant may be less than or equal to -5.1 eV, and the HOMO energy of the hole blocking layer may be at least 0.1 eV lower than the HOMO energy of the phosphorescent dopant.

[0017] The peak maximum wavelength of the phosphorescent dopant may be greater than or equal to 610 nm, greater than or equal to 620 nm, greater than or equal to 630 nm, greater than or equal to 650 nm, greater than or equal to 700 nm, greater than or equal to 750 nm, or greater than or equal to 800 nm.

[0018] OLEDs may place a hole blocking layer on the emissive layer.

[0019] The HOMO energy of the phosphorescent dopant may be less than or equal to -5.2 eV, less than or equal to -5.3 eV, or less than or equal to -5.4 eV. The HOMO energy of the hole blocking layer may be at least 0.2 eV lower than the HOMO energy of the phosphorescent dopant, at least 0.3 eV lower than the HOMO energy of the phosphorescent dopant, or at least 0.4 eV lower than the HOMO energy of the phosphorescent dopant.

[0020] The hole blocking layer may include a compound of formula I, which may be one or more of the following:

[0021]

[0022]

[0023] R 1 and R 2 Each can independently represent mono-substituted to the maximum permissible substitution or no substitution. 1 and R 2 can be independently hydrogen or deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino and / or combinations thereof. Y can be O, S, Se, NAr 4 , CAr 4 Ar 5 and SiAr 4 Ar 5Each Ar 1 -Ar 5 may be independently selected from aryl, heteroaryl and / or combinations thereof, and L may be a direct bond or a linking group comprising at least one aromatic ring. 1 and R 2 Y may be independently hydrogen or a substituent such as aryl, heteroaryl and / or a combination thereof. 4 In some embodiments, the compound of Formula I can be the only compound in the hole blocking layer.

[0024] The compound of formula I may be one or more of the following:

[0025]

[0026] The phosphorescent dopant can emit light from a triplet excited state to a ground singlet state in a device at room temperature. The phosphorescent dopant can be a metal coordination complex having a metal-carbon bond. The metal can be Ir, Os, Pt, Pd, Ag, Au, or Cu. The metal coordination complex can include a ligand having a chemical moiety of pyridazine, pyrimidine, pyrazine, and / or triazine. The metal coordination complex can have the formula M(L 1 ) x (L 2 ) y (L 3 ) z , where L 1 , L 2 and L 3 may be the same or different, wherein x is 1, 2 or 3, wherein y is 0, 1 or 2, wherein z is 0, 1 or 2, wherein x+y+z is the oxidation state of the metal M, wherein L 1 , L 2 and L 3 Can be independently selected from:

[0027]

[0028]

[0029] Where L 2 and L 3 It can also be Each Y 1 To Y 13 are independently selected from carbon and nitrogen, wherein Y' may be at least one of: BR e NR e , PR e ,O,S,Se,C=O,S=O,SO2,CR e R f 、SiR e Rf and GeR e R f , where R e and R f may be optionally fused or joined to form a ring wherein each R a , R b , R c and R d can independently represent a single substitution to the maximum possible number of substitutions or no substitution, wherein each R a , R b , R c , R d , R e and R f are independently selected from hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thio, sulfinyl, sulfonyl, phosphino, and combinations thereof, and wherein R a , R b , R c and R d Any two adjacent substituents of are optionally fused or joined to form a ring or to form a multidentate ligand.

[0030] The metal coordination complex may have the formula Ir(L A )3、Ir(L A )(L B )2、Ir(L A )2(L B )、Ir(L A )2(L C ) or Ir(L A )(L B )(L C ), where L A , L B and L C The metal coordination complex may have the formula Pt(L A )(L B ), where L A and L B can be the same or different, and where L A and L B Can optionally be linked to form a tetradentate ligand.

[0031] The metal coordination complex may have the formula Ir(L A )2(L C ), where L A Selected from:

[0032]

[0033]

[0034] Where L C yes And each R A and R B Can independently represent a single substitution to the maximum possible number of substitutions or no substitution. Each R A and R B R may be independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thio, sulfinyl, sulfonyl, phosphino, and combinations thereof. A and R B Any two adjacent substituents of may optionally be fused or joined to form a ring or to form a multidentate ligand.

[0035] The metal coordination complex may be selected from:

[0036]

[0037]

[0038]

[0039]

[0040]

[0041] The metal coordination complex may be a Pt complex with a tetradentate ligand. The tetradentate ligand may have four coordinating atoms selected from the following: (two anions C, two neutral N); (one anion C, one carbene C, one neutral N and one anion N); (two anions C, one carbene C, one neutral N); (one anion C, one anion N, two neutral N); (one anion C, one anion O, two neutral N); (two carbene C, two anions N).

[0042] The electron blocking layer may include a compound of formula II:

[0043]

[0044] Where R 3 , R 4 and R 5 can each independently represent a single substitution to the maximum permissible substitution or no substitution, wherein each R 3 , R 4and R 5 Ar may be independently hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thio, sulfinyl, sulfonyl, phosphino, and / or combinations thereof, and wherein each Ar 5 and Ar 6 Can be independently selected from aryl, heteroaryl and / or combinations thereof. Each R 3 , R 4 and R 5 and may independently be hydrogen or a substituent selected from aryl, heteroaryl, and / or combinations thereof.

[0045] In embodiments of the disclosed subject matter, the device can be of at least one type selected from the group consisting of a flat panel display, a computer monitor, a medical monitor, a television, a billboard, a light for interior or exterior lighting and / or signaling, a head-up display, a fully or partially transparent display, a flexible display, a laser printer, a telephone, a cellular telephone, a tablet computer, a phablet, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a microdisplay having an active area (with a major diagonal of 2 inches or less), a 3-D display, a virtual reality or augmented reality display, a vehicle, a video wall comprising multiple displays tiled together, a theater or stadium screen, and a sign. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 An organic light emitting device is shown.

[0047] Figure 2 An inverted organic light-emitting device without a separate electron transport layer is demonstrated.

[0048] Figure 3 An exemplary device structure is shown according to one embodiment of the disclosed subject matter.

[0049] Figure 4 Exemplary materials used in organic light emitting diode (OLED) devices according to embodiments of the disclosed subject matter are shown.

[0050] Figure 5 An exemplary phosphorescent organic light emitting diode (PHOLED) structure energy levels are shown according to one embodiment of the disclosed subject matter.

[0051] Figure 6 Graphs showing external quantum efficiency (EQE) versus current density for devices with RD1 and RD2 emitters according to embodiments of the disclosed subject matter.

[0052] Figure 7 Device materials according to embodiments of the disclosed subject matter are shown. DETAILED DESCRIPTION

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] More examples of each of these layers are available. For example, a flexible and transparent substrate-anode combination is disclosed in U.S. Patent No. 5,844,363, which is incorporated by reference in its entirety. An example of a p-doped hole transport layer is m-MTDATA doped with F4-TCNQ at a molar ratio of 50:1, 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 at a molar ratio of 1:1, 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 comprising a composite cathode 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.

[0058] 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 .

[0059] 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.

[0060] 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.

[0061] 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 include only 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 may directly emit light itself using an applied 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 layers may not be considered an "emission layer" as disclosed herein. In general, an "emission layer" or material is one of the following "emission layers" or materials that emit initial light, which may be changed by another layer in the device that does not emit initial light itself, such as a color filter or other color-changing layer, but may re-emit changed light of different spectral content based on the initial light emitted by the emission layer.

[0062] 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.

[0063] 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.

[0064] 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 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, phablets, 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 may 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 comfortable for humans, such as 18°C ​​to 30°C, and more preferably at room temperature (20-25°C), but may be used outside this temperature range (e.g., -40°C to +80°C).

[0065] 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.

[0066] Embodiments of the disclosed subject matter may provide an organic light emitting diode (OLED) having an anode, a cathode, an emission layer disposed between the anode and the cathode, and a hole blocking layer disposed between the emission layer and the cathode. The emission layer may include a phosphorescent dopant. The phosphorescent dopant has an emission with a peak maximum wavelength greater than or equal to 600 nm in a 0.5% doped PMMA (poly(methyl methacrylate)) film at room temperature. The highest occupied molecular orbital (HOMO) energy of the phosphorescent dopant may be less than or equal to -5.1 eV, and the HOMO energy of the hole blocking layer may be at least 0.1 eV lower than the HOMO energy of the phosphorescent dopant. In some embodiments, the OLED may have a hole blocking layer disposed on the emission layer.

[0067] The peak maximum wavelength of the phosphorescent dopant may be greater than or equal to 610 nm, greater than or equal to 620 nm, greater than or equal to 630 nm, greater than or equal to 650 nm, greater than or equal to 700 nm, greater than or equal to 750 nm, or greater than or equal to 800 nm.

[0068] The HOMO energy of the phosphorescent dopant may be less than or equal to -5.2 eV, less than or equal to -5.3 eV, or less than or equal to -5.4 eV. The HOMO energy of the hole blocking layer may be at least 0.2 eV lower than the HOMO energy of the phosphorescent dopant, at least 0.3 eV lower than the HOMO energy of the phosphorescent dopant, or at least 0.4 eV lower than the HOMO energy of the phosphorescent dopant.

[0069] The hole blocking layer may include a compound of formula I, which may be one or more of the following:

[0070]

[0071]

[0072] R 1 and R 2 Each can independently represent mono-substituted to the maximum permissible substitution or no substitution. 1 and R 2 can be independently hydrogen or deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silane, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thio, sulfinyl, sulfonyl, phosphino and / or combinations thereof. Y can be O, S, Se, NAr 4 , CAr 4 Ar 5 、SiAr 4 Ar 5 、Fluorene(C-Ar 1 Ar2 ) and / or silicon (Si-Ar 1 Ar 2 ), where Ar 1 and Ar 2 The aromatic groups may be the same or different. 1 -Ar 5 may be independently selected from aryl, heteroaryl and / or combinations thereof, and L may be a direct bond or a linking group comprising at least one aromatic ring. 1 and R 2 Y may be independently hydrogen or a substituent such as aryl, heteroaryl and / or a combination thereof. 4 In some embodiments, the compound of Formula I can be the only compound in the hole blocking layer.

[0073] The compound of formula I may be one or more of the following:

[0074]

[0075] In some embodiments, the compound of formula I may be one or more of the following:

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092] The phosphorescent dopant can emit light from a triplet excited state to a ground singlet state in a device at room temperature. The phosphorescent dopant can be a metal coordination complex having a metal-carbon bond. The metal can be Ir, Os, Pt, Pd, Ag, Au, or Cu. The metal coordination complex can include a ligand having a chemical moiety of pyridazine, pyrimidine, pyrazine, and / or triazine. The metal coordination complex can have the formula M(L 1 ) x (L 2 ) y (L 3 ) z , where L 1 , L 2 and L 3 may be the same or different, wherein x is 1, 2 or 3, wherein y is 0, 1 or 2, wherein z is 0, 1 or 2, wherein x+y+z is the oxidation state of the metal M, wherein L 1 , L 2 and L 3 Can be independently selected from:

[0093]

[0094]

[0095] Where L 2 and L 3 It can also be Each Y 1 To Y 13 are independently selected from carbon and nitrogen, wherein Y' may be at least one of: BR e NR e , PR e ,O,S,Se,C=O,S=O,SO2,CR e R f 、SiR e R f and GeR e R f , where R e and R f may be optionally fused or joined to form a ring wherein each R a , R b , R c and R d can independently represent a single substitution to the maximum possible number of substitutions or no substitution, wherein each R a , R b , R c, R d , R e and R f are independently selected from hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thio, sulfinyl, sulfonyl, phosphino, and combinations thereof, and wherein R a , R b , R c and R d Any two adjacent substituents of are optionally fused or joined to form a ring or to form a multidentate ligand.

[0096] The metal coordination complex may have the formula Ir(L A )3、Ir(L A )(L B )2、Ir(L A )2(L B )、Ir(L A )2(L C ) or Ir(L A )(L B )(L C ), where L A , L B and L C The metal coordination complex may have the formula Pt(L A )(L B ), where L A and L B can be the same or different, and where L A and L B Can optionally be linked to form a tetradentate ligand.

[0097] The metal coordination complex may have the formula Ir(L A )2(L C ), where L A Selected from:

[0098]

[0099]

[0100] Where L C for And each R A and R B Can independently represent a single substitution to the maximum possible number of substitutions or no substitution. Each R A and R BR may be independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thio, sulfinyl, sulfonyl, phosphino, and combinations thereof. A and R B Any two adjacent substituents of may optionally be fused or joined to form a ring or to form a multidentate ligand.

[0101] In some embodiments, the metal coordination complex may be selected from:

[0102]

[0103]

[0104]

[0105]

[0106]

[0107] The metal coordination complex may be a Pt complex with a tetradentate ligand. The tetradentate ligand may have four coordinating atoms selected from the following: (two anions C, two neutral N); (one anion C, one carbene C, one neutral N and one anion N); (two anions C, one carbene C, one neutral N); (one anion C, one anion N, two neutral N); (one anion C, one anion O, two neutral N); (two carbene C, two anions N).

[0108] The electron blocking layer may include a compound of formula II:

[0109]

[0110] Where R 3 , R 4 and R 5 can each independently represent a single substitution to the maximum permissible substitution or no substitution, wherein each R 3 , R 4 and R 5 Ar may be independently hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thio, sulfinyl, sulfonyl, phosphino, and / or combinations thereof, and wherein each Ar 5 and Ar 6 Can be independently selected from aryl, heteroaryl and / or combinations thereof. Each R3 , R 4 and R 5 and may independently be hydrogen or a substituent selected from aryl, heteroaryl, and / or combinations thereof.

[0111] The electron blocking layer may include a compound selected from the group consisting of:

[0112]

[0113]

[0114]

[0115] 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.

[0116] 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.

[0117] In some embodiments of the emission region, the emission region further comprises a body.

[0118] 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.

[0119] 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.

[0120] 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 minimal role in charge transport. In some embodiments, the host may include a metal complex. The host may be an inorganic compound.

[0121] Combination with other materials

[0122] 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.

[0123] 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.

[0124] Conductive dopants:

[0125] 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.

[0126] HIL / HTL:

[0127] 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.

[0128] EBL:

[0129] 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.

[0130] main body:

[0131] 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.

[0132] HBL:

[0133] 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.

[0134] ETL:

[0135] 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 generally used to transport electrons.

[0136] Charge Generation Layer (CGL)

[0137] In a tandem or stacked OLED, the CGL plays a fundamental role in the performance and consists 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.

[0138] experiment

[0139] The deep HOMO emitter may be a phosphorescent organic light emitting diode (PHOLED) emitter having a narrow spectrum, a high luminous efficiency / external quantum efficiency (LE / EQE) ratio, a long lifetime, and an EQE value above a predetermined amount. For example, the full width at half maximum (FHWM) value of the narrow spectrum of the deep HOMO emitter may be less than 50 nm, less than 45 nm, less than 40 nm, and the like. Due to the narrow electroluminescence (EL) spectrum, the amount of photons emitted in the non-visible range exceeding 670 nm may be minimized compared to conventional broad red emitters, and thus less photon loss may occur. Most of the emitted photons may be in the visible range, which for narrow EL emitters may provide higher brightness efficiency at the same EQE.

[0140] A variety of narrow EL emitters can have a deeper HOMO level (e.g., ~-5.3 eV) when compared to the HOMO level of a broad emitter (e.g., ~-5.1 eV). This can result in different behaviors of the emitters in a device. Embodiments of the disclosed subject matter can provide different approaches to efficient device structure architectures for deep HOMO emitters, such as for deep HOMO red emitters.

[0141] A wide range of deep HOMO emitter families can have desirable PHOLED performance with narrow spectrum, high LE / EQE ratio, long lifetime, and potentially very high EQE. Due to the narrow EL spectrum, the amount of photons emitted in the non-visible range beyond 670 nm can be minimized and thus fewer photon losses occur compared to conventional broad red emitters. Most of the emitted photons can be in the visible range, providing higher brightness efficiency at the same EQE for narrow EL emitters.

[0142] A variety of narrow EL emitters can have a deeper HOMO level (eg, -5.3 eV) when compared to the HOMO level of a broad emitter (eg, -5.1 eV). This can lead to different behaviors of the emitters in a device and different device structural architectures can be used for deep HOMO emitters.

[0143] In addition to narrow red emitters, there may also be a family of green emitters with desirable properties and a deep HOMO (eg, >5.2 eV) and similar device structure architectures may be used.

[0144] Embodiments of the disclosed subject matter provide for the design of efficient device structures for deep HOMO emitters. There may be differences in device characteristics between emitters RD1 and RD2 in the same device structure (e.g., Figure 6 and Table 2). The difference may be attributed to the recombination zone (RZ) location in the EML. The hole blocking layer (HBL) may affect the efficiency of the deep HOMO RD1 emitter device, while the electron blocking layer (EBL) may not affect the efficiency (e.g., as shown in Examples 1, 2, 3, 4 of Table 2). For emitter RD2, there may be no difference in device efficiency due to the HBL, but there may be a difference due to the EBL (see, e.g., Examples 5, 6, 7, 8 of Table 2).

[0145] The RD1 device may have a recombination zone close to the HBL side of the emissive layer (EML). The HBL can improve the RD1 device efficiency by preventing exciton quenching and electron leakage to the electron transport layer (ETL). For the same reason, the RD2 device may have a recombination zone (RZ) close to the EBL, and the EBL can improve the device efficiency by preventing exciton quenching and electron leakage to the hole transport layer (HTL). Since there may be less hole capture, the deep HOMO RD1 can provide improved hole transport to the HBL side of the EML. In contrast, since there may be more hole capture, the reference shallow HOMO RD2 may not provide sufficient hole transport through the EML. The RZ may be localized so as to be near the EBL.

[0146] Embodiments of the disclosed subject matter can provide a combination of a deep HOMO emitter and a HBL to provide improved device efficiency. Efficiency roll-off with increasing brightness can be problematic for phosphorescent devices, and reduction of efficiency roll-off can be important in order to provide increased device efficiency at higher brightness. The EQE roll-off can be calculated as 10 mA / cm for the same device. 2 EQE at 1mA / cm 2 The ratio of EQE of (see, for example, the last column of Table 2). Table 2 and Figure 6 The data in show that HBL can provide a reduction in efficiency roll-off for RD1 deep HOMO emitters (see, e.g., Example 1 vs. Example 2 and Example 3 vs. Example 4 in Table 2), and can have no or minimal roll-off effect on devices with RD2 emitters (see, e.g., Example 6 vs. Example 5 and Example 7 vs. Example 8 in Table 2).

[0147] All exemplary devices were placed under high vacuum (<10 -7 The anode electrode is The cathode is made of indium tin oxide (ITO). 8-Hydroxyquinoline lithium (Liq) followed by Immediately after fabrication, all devices were encapsulated with epoxy-sealed glass lids in a nitrogen glove box (<1 ppm H2O and O2), and a moisture absorber was incorporated into the package. The organic stack of the device example included, from the ITO surface Hexaazatriphenylenehexacarbonitrile (HAT-CN) as hole injection layer (HIL); 400 or Hole transport material (HTM) as hole transport layer (HTL); Electron blocking material (EBM) (if present) as electron blocking layer (EBL); containing red host H1 and 3% RD1 or RD2 red emitter Emission layer (EML), HBM as hole blocking layer (HBL) (if present) and 300% doped with 35% ETM as ETL (HBL present) or (HBL free) 8-Hydroxyquinolate lithium (Liq).

[0148] Figure 3 A device structure according to one embodiment of the disclosed subject matter is shown. The device may include a cathode, an electron ejection layer (EIL), an electron transport layer (ETL), an optional hole blocking layer (HBL), an emissive layer (EML), an optional electron blocking layer (EBL), a hole transport layer (HTL), a hole injection layer (HIL), and an anode.

[0149] When EBL is not included, the HTL thickness is thicker And when HBL is not included, ETL thickness is thicker The overall device thickness is kept the same to prevent possible device performance distortion due to different layer thicknesses.

[0150] Table 1 shows the device layer thicknesses and materials. The chemical structures of the device materials are shown in Figure 4 middle.

[0151]

[0152] Table 1. Device layer materials and thicknesses

[0153] After fabrication, the devices were subjected to EL and current density, voltage, luminance (JVL) testing. The device performance data are summarized in Table 2.

[0154]

[0155] Table 2. Device structures and performance of devices with multiple red emitters and blocking layers.

[0156] In order to understand the device performance, the HOMO-LUMO and T1 energy levels of the materials have been used. The energy levels were determined by solution cyclic voltammetry and differential pulse voltammetry. The measurements were performed using a CH Instruments model 6201B potentiostat using anhydrous dimethylformamide solvent and tetrabutylammonium hexafluorophosphate as the supporting electrolyte. Glassy carbon and platinum and silver wires were used as working, counter and reference electrodes, respectively. The electrochemical potential was referenced to the internal ferrocene-ferrocene redox pair (Fc / Fc+) by measuring the peak potential difference according to differential pulse voltammetry. The corresponding highest occupied molecular orbital (HOMO) energy and the lowest unoccupied molecular orbital (LUMO) energy (relative to vacuum, 4.8 eV) were determined for ferrocene by reference to the cation and anion redox potentials. That is:

[0157] HOMO=-(CVox)-4.8(eV)

[0158] LUMO=-(CV red)-4.8(eV)

[0159] To determine the T1 energy level, less than 1 mg of material was dissolved by ultrasonic treatment in 2 mL of 2-methyltetrahydrofuran solvent. The solution was filtered through a 2 micron filter into a quartz tube. The tube was sealed with a rubber septum and degassed with nitrogen bubbling to prevent oxygen quenching. Phosphorescence spectroscopy was performed at a low temperature of nearly 77 K on a Horiba Jobin Yvon Fluorolog-3 system equipped with a xenon lamp. T1 was determined using PL at 77 K. That is:

[0160] T1(eV)=1240 / triplet wavelength[nm]

[0161] The HOMO-LUMO and T1 energy levels are listed in Table 3 below, and Figure 5 Shown are HOMO-LUMO energy levels of device materials according to embodiments of the disclosed subject matter.

[0162]

[0163]

[0164] Table 3. Energy levels of materials used in device examples and the calculated energy levels of T1HBM are shown below and may have similarities with Compound H:

[0165]

[0166] Density Functional Theory (DFT) T1 421 S1 370 Energy Gap 3.804 HOMO -5.795 LUMO -1.991

[0167] There may be differences in device characteristics between emitters RD1 and RD2 in the same device structure (see, e.g., Figure 6 and Table 2), and it may be based on the recombination zone (RZ) position in the EML. The HBL may affect the efficiency of deep HOMO RD1 emitter devices, while the EBL may not affect the efficiency (see, e.g., Examples 1, 2, 3, 4 in Table 2).

[0168] In contrast, in the case of the reference emitter RD2, there may be no difference in device efficiency due to the HBL, but there may be a difference due to the EBL (see, e.g., Examples 5, 6, 7, 8 of Table 2). The RD1 device may have a recombination zone close to the HBL side of the EML, and the HBL may improve the RD1 device efficiency by preventing exciton quenching and electron leakage to the ETL. When the RD2 device may have a recombination zone RZ close to the EBL, the EBL may improve the device efficiency by preventing exciton quenching and hole leakage to the HTL.

[0169] The deep HOMO RD1 may exhibit less hole trapping and / or improved hole transport, which may provide a higher exciton population on the cathode side close to the EML. In contrast, the reference shallow HOMO RD2 may perform hole trapping to a greater extent and / or perform hole transport through the EML to a lesser extent, which may provide an RZ confined near the EBL. In embodiments of the disclosed subject matter, the combination of a deep HOMO emitter and a HBL may provide desired device efficiencies.

[0170] The efficiency roll-off that accompanies increased brightness can be problematic for phosphorescent devices. A reduction in the efficiency roll-off can provide higher device efficiency at higher brightness. The EQE roll-off is calculated as 10 mA / cm for the same device. 2 EQE at 1mA / cm 2 The ratio of EQE of (see, for example, the last column of Table 2). Table 2 and Figure 6 The data in show that the HBL provides a reduction in efficiency roll-off for RD1 deep HOMO emitters (see, e.g., Example 1 vs. Example 2 and Example 3 vs. Example 4 in Table 2), and has no or minimal roll-off effect on devices with RD2 emitters (see, e.g., Example 6 vs. Example 5 and Example 7 vs. Example 8 in Table 2).

[0171] The hole transport layer (HTM) may have good hole transport properties (e.g., HOMO 5.16 eV). The electron blocking layer (EBL) may have a shallow LUMO energy level (e.g., 1.84 eV) to prevent electrons from leaking to the HTL; and a high T1 energy (e.g., 452 nm) sufficient to prevent any excitons from leaking from the EML to the HTL; and reasonable hole transport properties (e.g., HOMO 5.38 eV).

[0172] In embodiments of the disclosed subject matter, the EBL T1 can be higher than the T1 of the emitter. In the absence of an emitter with a shallower HOMO level, the host (host 1) can provide electron transport through the EML (e.g., LUMO 2.88 eV), as well as hole transport (e.g., HOMO 5.43 eV). Embodiments of the disclosed subject matter can include one or more hosts (e.g., single host, dual host, etc.).

[0173] Shallow HOMO emitters, such as RD2- (HOMO 5.05 eV) can provide more hole trapping, and deep HOMO emitters, such as RD1 (HOMO 5.32 eV) can provide more hole transport through the EML. This can shift the recombination zone in the EML, which depends on the emitter. With deep HOMO emitters, the recombination zone can shift towards the HBL. With RD1 deep HOMO emitters, the impact of the HBL on device efficiency can be more significant. RD2 can provide more hole trapping, resulting in less hole transport through the EML, so the RZ can shift towards the EBL interface. The EBL can affect the efficiency of RD2 emitter devices.

[0174] The HOMO of the deep HOMO emitter may be in the range of 5.1-5.6 eV, more preferably 5.15-5.55 eV, even more preferably 5.2-5.5 eV.

[0175] Hole capture can vary with the emitter-host HOMO energy gap. The HBL of the emitter-host energy gap can be below 0.15 eV. The hole blocking material (HBM) can have a deep HOMO (5.96 eV) that can block holes from leaking into the ETL and can have a high T1 (e.g., 484 nm) to prevent excitons from leaking into the ETL. In an embodiment of the disclosed subject matter, the HBL can have a HOMO energy level deeper than 5.5 eV.

[0176] The ETM may provide electron transport through the ETL toward the EML (eg, LUMO 2.71 eV).

[0177] The combination of deep HOMO emitter R1 and HBL in the devices and / or structures of the disclosed subject matter can provide increased efficiency, minimal efficiency roll-off, and increased power efficiency.

[0178] Embodiments of the disclosed subject matter can provide the following types of red emitters with deep HOMOs:

[0179]

[0180] Embodiments of the disclosed subject matter can provide deep HOMO red ligand structures for emissive ligands:

[0181]

[0182] CF3 with auxiliary ligand can provide a deeper HOMO:

[0183]

[0184] The above may be combined with one or more other emissive ligands to shift the HOMO by 0.1 to 0.15 eV (or higher if multiple CF3 groups are present).

[0185] In some embodiments, the OLED may include at least one emitter selected from the group of emitters shown below.

[0186]

[0187]

[0188]

[0189]

[0190]

[0191] Additional device data was obtained to show compounds of blocking layer materials and host classes that can provide improvements to the performance of deep HOMO red emitter devices with blocking layers. Two hosts, single host 1 and dual host 2: host 3 (4:1) and three blocking layer materials (e.g., HBL1, HBL2, HBL3) were used in devices with deep HOMO emitter RD1 and shallow HOMO emitter RD2. Both emitters had approximately the same color saturation, but had different types of energy levels.

[0192] The device was manufactured as described above, and Figure 7 Device materials according to embodiments of the disclosed subject matter are shown.

[0193] The experimental data are summarized in Table 4 below, which shows the dependence of the device EQE on the barrier layers in the device.

[0194]

[0195] Table 4. Device performance of other experiments. Effect of HBL on EQE of deep HOMO red emitter structures.

[0196] The EQE of a device with a deep HOMO RD1 emitter can be affected by a blocking layer (BL) and can be about 10% higher relative to the EQE of a device without a BL. For a single host, as shown in Examples 9, 10, and 11, the EQE of the accompanying blocking layer structure can be about 20%. In contrast, Example 12 shows that the EQE of a reference structure without a BL can be about 18%.

[0197] Dual host devices with RD1 deep HOMO emitters can be similarly affected by BL. In Examples 13, 14, and 15, the EQE of the BL structure is about 24%. In Example 16, the EQE of the device without the BL structure can be ~22%.

[0198] The EQE of devices with RD2 shallow HOMO emitters may not be affected by the HBL. In single host Examples 17, 18, and 19, the EQE of the BL device may be similar to the EQE of the device without the BL (e.g., Example 20, where the EQE is about 24%). The EQE of the dual host device including the BL, such as in Examples 21, 22, and 23, may be similar to the EQE of the device without the BL of Example 24 (e.g., about 25%).

[0199] Different classes of BL materials can be used with HOMO emitters. Examples BL1, BL2, BL3 and / or HBM can belong to the following classes of materials: aluminum quinoline complexes, aza-dibenzothiophene derivatives, indolo[2,3-a]carbazole derivatives, 4,6-disubstituted dibenzothiophene. These different classes can serve as BL materials for deep HOMO red emitter PHOLED devices.

[0200] The energy levels of other host and barrier layers are shown above in Table 3. Table 3 shows the energy levels of all materials used in the device examples.

[0201] 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. An organic light emitting diode (OLED), comprising: anode; cathode; an emissive layer disposed between the anode and the cathode; and a hole blocking layer disposed between the emitting layer and the cathode, wherein the emitting layer comprises a phosphorescent dopant, wherein the phosphorescent dopant has emission with a peak maximum wavelength greater than or equal to 600 nm in a 0.5% doped poly(methyl methacrylate) PMMA film at room temperature, wherein the highest occupied molecular orbital HOMO energy of the phosphorescent dopant is less than or equal to −5.1 eV, and wherein the HOMO energy of the hole blocking layer is at least 0.1 eV lower than the HOMO energy of the phosphorescent dopant.

2. The OLED of claim 1 , wherein the peak maximum wavelength of the phosphorescent dopant is selected from the group consisting of: greater than or equal to 610 nm, greater than or equal to 620 nm, greater than or equal to 630 nm, greater than or equal to 650 nm, greater than or equal to 700 nm, greater than or equal to 750 nm, and greater than or equal to 800 nm.

3. The OLED of claim 1, wherein the HOMO energy of the phosphorescent dopant is selected from the group consisting of: less than or equal to -5.2 eV, less than or equal to -5.3 eV, and less than or equal to -5.4 eV.

4. The OLED of claim 1 , wherein the HOMO energy of the hole blocking layer is selected from the group consisting of: at least 0.2 eV lower than the HOMO energy of the phosphorescent dopant, at least 0.3 eV lower than the HOMO energy of the phosphorescent dopant, and at least 0.4 eV lower than the HOMO energy of the phosphorescent dopant.

5. The OLED according to claim 1, wherein the hole blocking layer comprises a compound of formula I, which is at least one selected from the group consisting of: Where R 1 and R 2 Each independently represents monosubstituted to the maximum permissible substitution or no substitution, Each R 1 and R 2 are independently hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof, Wherein Y is selected from the group consisting of: O, S, Se, NAr 4 , CAr 4 Ar 5 、SiAr 4 Ar 5 、Fluorene(C-Ar 1 Ar 2 ) and silicon (Si-Ar 1 Ar 2 ), and wherein Ar 1 and Ar 2 are the same or different aromatic groups, Each Ar 1 -Ar 5 are independently selected from the group consisting of aryl, heteroaryl, and combinations thereof, and wherein L is a direct bond or a linking group comprising at least one aromatic ring.

6. The OLED according to claim 5, wherein Y is selected from the group consisting of: O, S and NAr 4 .

7. The OLED according to claim 1, wherein the phosphorescent dopant is a metal coordination complex having a metal-carbon bond.

8. The OLED according to claim 7, wherein the metal is selected from the group consisting of Ir, Os, Pt, Pd, Ag, Au and Cu.

9. The OLED of claim 7, wherein the metal coordination complex comprises a ligand comprising a chemical moiety selected from the group consisting of: pyridazine, pyrimidine, pyrazine, and triazine.

10. The OLED according to claim 7, wherein the metal coordination complex has the formula M(L 1 ) x (L 2 ) y (L 3 ) z , where L 1 , L 2 and L 3 can be the same or different, where x is 1, 2, or 3, where y is 0, 1, or 2, where z is 0, 1, or 2, where x+y+z is the oxidation state of the metal M, Where L 1 , L 2 and L 3 Each independently selected from the group consisting of: One of L2 and L3 can also be Each Y 1 To Y 13 independently selected from the group consisting of carbon and nitrogen, Wherein Y' is selected from the group consisting of: BR e NR e , PR e ,O,S,Se,C=O,S=O,SO2,CR e R f 、SiR e R f and GeR e R f ; Where R e and R f optionally fused or joined to form a ring; Each R a , R b , R c and R d can independently represent a single substitution to the maximum possible number of substitutions or no substitution, Each R a , R b , R c , R d , R e and R f are each independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof, and Where R a , R b , R c and R d Any two adjacent substituents of are optionally fused or joined to form a ring or to form a multidentate ligand.

11. The OLED according to claim 10, wherein the metal coordination complex has a formula selected from the group consisting of: Ir(L A )3、Ir(L A )(L B )2、Ir(L A )2(L B )、Ir(L A )2(L C ) and Ir(L A )(L B )(L C );where L A , L B and L C Different from each other.

12. The OLED according to claim 10, wherein the metal coordination complex has the formula Pt(L A )(L B ),in LA and L B can be the same or different, and in LA and L B Optionally linked to form a tetradentate ligand.

13. The OLED according to claim 11, wherein the metal coordination complex has the formula Ir(L A )2(L C ), Where L A Select from the group consisting of: Where L C yes and Each R A and R B can independently represent a single substitution to the maximum possible number of substitutions or no substitution, Each R A and R B independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof, and Where R A and R B Any two adjacent substituents of are optionally fused or joined to form a ring or to form a multidentate ligand.

14. The OLED according to claim 1, wherein the OLED further comprises an electron blocking layer, wherein the electron blocking layer comprises a compound of formula II: Where R 3 , R 4 and R 5 Each independently represents monosubstituted to the maximum permissible substitution or no substitution, Each R 3 , R 4 and R 5 are independently hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, phosphino, and combinations thereof, and Each Ar 5 and Ar 6 are independently selected from the group consisting of aryl, heteroaryl, and combinations thereof.

15. A consumer product comprising an organic light emitting device (OLED) comprising: anode; cathode; an emissive layer disposed between the anode and the cathode; and a hole blocking layer disposed between the emitting layer and the cathode, wherein the emitting layer comprises a phosphorescent dopant, wherein the phosphorescent dopant has emission with a peak maximum wavelength greater than or equal to 600 nm in a 0.5% doped poly(methyl methacrylate) PMMA film at room temperature, wherein the highest occupied molecular orbital HOMO energy of the phosphorescent dopant is less than or equal to −5.1 eV, and wherein the HOMO energy of the hole blocking layer is at least 0.1 eV lower than the HOMO energy of the phosphorescent dopant.

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