Deep HOMO (Highest Occupied Molecular Orbital) Emitting Device Structure

JP7909505B2Active Publication Date: 2026-08-21UNIVERSAL DISPLAY CORP
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Patent Information

Application Number
JP2023156586
Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
Priority Date
2019-10-09
Filing Date
2023-09-22
Publication Date
2026-08-21
Estimated Expiration
2039-10-16

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Abstract

To provide an organic light-emitting diode having a high luminous efficiency and exhibiting light emission of a maximum peak wavelength of 600 nm or more.SOLUTION: An organic light-emitting diode (OLED) comprises an anode, a cathode, and an emissive layer disposed between the anode and cathode, and a hole-blocking layer disposed between the emissive layer and cathode. The emissive layer may contain a phosphorescence dopant. The phosphorescence dopant exhibits light emission having a maximum peak wavelength of 600 nm or more at a room temperature in a thin film arranged by doping PMMA(poly(methyl methacrylate)) therewith by 0.5%. Of the phosphorescence dopant, the energy of the highest occupied molecular orbital (HOMO) may be -5.1 eV or under. HOMO energy of the hole-blocking layer is lower than HOMO energy of the phosphorescence dopant by at least 0.1 eV.SELECTED DRAWING: Figure 3
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Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority to U.S. Patent Application No. 62 / 749,290, filed October 23, 2018, which is incorporated by reference in its entirety.

[0002] The present invention relates to a compound for use as a light-emitting material, and to a device such as an organic light-emitting diode containing the same. [Background technology]

[0003] Organic optoelectronic devices are becoming increasingly desirable for several reasons. Because many of the materials used to fabricate such devices are relatively inexpensive, organic optoelectronic devices have the potential to offer a cost advantage over inorganic devices. In addition, due to the inherent properties of organic materials, such as flexibility, they can be well-suited for specific applications, such as fabrication on flexible substrates. Examples of organic optoelectronic devices include organic light-emitting diodes / devices (OLEDs), organic phototransistors, organic photocells, and organic photodetectors. For OLEDs, organic materials can offer performance advantages over conventional materials. For example, the wavelength of light emitted by the organic light-emitting layer can generally be easily adjusted with appropriate dopants.

[0004] OLEDs utilize a thin organic film that emits light when a voltage is applied to the entire device. OLEDs are becoming an increasingly interesting technology for use in applications such as flat panel displays, lighting, and backlighting. Several OLED materials and configurations are described in Patent Documents 1, 2, and 3, which are incorporated herein by reference in their entirety.

[0005] One application of phosphorescent molecules is in full-color displays. Industry standards for such displays require pixels adapted to emit specific colors, known as "saturated" colors. In particular, these standards require saturated red, green, and blue pixels. Alternatively, OLEDs can be designed to emit white light. Conventional liquid crystal displays emit light from a white backlight, which is filtered using absorption filters to produce red, green, and blue light. Similar techniques can be used with OLEDs. White OLEDs can be either a single EML device or a stacked structure. Color can be measured using CIE coordinates, which are well known in the art.

[0006] As used herein, the term “organic” includes polymer materials and small molecule organic materials that can be used to fabricate organic optoelectronic devices. “Small molecule” refers to any organic material that is not a polymer, and “small molecule” can actually be quite large. Small molecules can contain repeating units in some contexts. For example, using long-chain alkyl groups as substituents does not exclude molecules from the “small molecule” class. Small molecules may be incorporated into polymers, for example, as pendant groups on a polymer backbone or as part of said backbone. Small molecules can also serve as the core portion of a dendrimer, which consists of a series of chemical shells constructed on a core portion. The core portion of a dendrimer may be a fluorescent or phosphorescent small molecule emitter. Dendrimers can be “small molecules,” and all dendrimers currently used in the field of OLEDs are considered to be small molecules.

[0007] In this specification, “top” means the part furthest from the substrate, while “bottom” means the part closest to the substrate. When it is stated that the first layer is “placed on top of” the second layer, the first layer is located further from the substrate. There may be other layers between the first and second layers unless it is specified that the first layer is “in contact with” the second layer. For example, a cathode may be described as “placed on top of” the anode, even if there are various organic layers in between.

[0008] As used herein, “solution processable” means that it can be dissolved, dispersed or transported in any liquid medium, either in solution or suspension form, and / or deposited from said medium.

[0009] A ligand may be referred to as "photoactive" if it is considered to directly contribute to the photoactive properties of the light-emitting material. A ligand may be referred to as "auxiliary" if it is not considered to contribute to the photoactive properties of the light-emitting material, although auxiliary ligands can alter the properties of photoactive ligands.

[0010] As used herein, as will be generally understood by those skilled in the art, the first “highest occupied molecular orbital” (HOMO) or “lowest empty molecular orbital” (LUMO) energy level is “greater than” or “higher than” the second HOMO or LUMO energy level, if the first energy level is close to the vacuum energy level. Since the ionization potential (IP) is measured as a negative energy relative to the vacuum level, a higher HOMO energy level corresponds to an IP with a smaller absolute value (less negative IP). Similarly, a higher LUMO energy level corresponds to an electron affinity (EA) with a smaller absolute value (less negative EA). In a conventional energy level diagram with the vacuum level at the top, the LUMO energy level of a material is higher than the HOMO energy level of the same material. “Higher” HOMO or LUMO energy levels appear to be closer to the top of such a diagram than “lower” HOMO or LUMO energy levels.

[0011] As used herein, as will be generally understood by those skilled in the art, if the first work function has a higher absolute value, then the first work function is "greater than" or "higher than" the second work function. Since work functions are generally measured as negative numbers relative to the vacuum level, this means that a "higher" work function is even more negative. In a conventional energy level diagram with the vacuum level at the top, a "higher" work function is illustrated as being far away from the vacuum level in the downward direction. Thus, the definitions of the HOMO and LUMO energy levels follow a different convention than that of the work function.

[0012] Further details and the definitions described above for OLEDs can be found in Patent Document 4, which is incorporated herein by reference in its entirety. [Overview of the project]

[0013] According to the 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 the embodiment, the organic light-emitting device is incorporated into one or more devices selected from consumer products, electronic component modules, and / or lighting panels.

[0014] Embodiments of the disclosed subject matter can 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. The phosphorescent dopant has emission with a peak maximum wavelength of 600 nm or more at room temperature in a thin film doped with 0.5% PMMA (poly(methyl methacrylate)). The energy of the highest occupied molecular orbital (HOMO) of the phosphorescent dopant may be -5.1 eV or less, and the energy of the HOMO of the hole-blocking layer may be at least 0.1 eV lower than the energy of the HOMO of the phosphorescent dopant.

[0015] The peak maximum wavelength of the phosphorescent dopant can be 610 nm or higher, 620 nm or higher, 630 nm or higher, 650 nm or higher, 700 nm or higher, 750 nm or higher, or 800 nm or higher.

[0016] The OLED may have the hole blocking layer disposed on the light-emitting layer.

[0017] The HOMO energy of the phosphorescent dopant may be -5.2 eV or less, -5.3 eV or less, or -5.4 eV or less. 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.

[0018] The hole blocking layer may be one or more of the following compounds, including the compound of formula I. [ka] In the formula, R 1 and R 2 Each of these may independently represent the maximum permissible substitution from the mono, or it may represent no substitution at all. 1 and R 2 Each of these may independently be hydrogen or deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphinol, and / or combinations thereof. Y is O, S, Se, Nar 4 CAr 4 Ar 5 , and SiAr 4 Ar5 It may also be Ar 1 ~Ar 5 may each independently be selected from aryl, heteroaryl, and / or combinations thereof, and L may be a direct bond or a linker containing at least one aromatic ring. R 1 and R 2 may each independently be hydrogen or a substituent such as aryl, heteroaryl, and / or combinations thereof. Y may be O, S, and / or NAr<https: / / patentscope.wipo.int / search / en / 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[ka] L 2 and L 3 Also, see below: [ka] It can be Y 1 ~Y 13 These are independently selected from carbon and nitrogen, and Y' is 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 It may be at least one of R e and R f These may optionally condense or bond to form a ring, R a , R b , R c , and R d Each of these may independently represent the maximum number of possible substitutions from mono-substitutions, or they may represent no substitutions, R a , R b , R c , R d , R e , and R f Each is independently selected from hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphinol, and combinations thereof, R a , R b , R c , and R d Any two adjacent substituents can optionally condense or bond to form a ring or a polydentate ligand.

[0021] The aforementioned metal coordination complex is 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 ) can have the formula, L A , L B , and L C These are different from each other. The metal coordination complex is Pt(L A )(L B ) can have the formula, L A and L B They can be the same or different, L A and L B These elements may optionally combine to form a tetradentate ligand.

[0022] The aforementioned metal coordination complex is Ir(L A )2(L C ) can have the formula, L A The following can be selected: [ka] L C The following: TIFF0007909505000007.tif2728, R A and R B Each of these may independently represent either the maximum number of possible substitutions from a mono-substitution or the absence of substitutions. A and R BEach of these may be independently selected from hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphinol, and combinations thereof. A and R B Any two adjacent substituents may optionally condense or bond to form a ring, or form a polydentate ligand.

[0023] The aforementioned metal coordination complex can be selected from the following: [ka] [ka] [ka] [ka] [ka] The metal-coordinated complex may be a Pt complex having a tetradentate ligand. The tetradentate ligand may have four coordinating atoms selected from (two anionic C, two neutral N); (one anionic C, one carbene C, one neutral N, and one anionic N); (two anionic C, one carbene C, one neutral N); (one anionic C, one anionic N, two neutral N); (one anionic C, one anionic O, two neutral N); (two carbene C, two anionic N). The electron-blocking layer may have a compound of formula II. [ka] In the formula, R 3 , R4 and R 5 each independently may represent a maximum allowable substitution from a single entity or may represent no substitution, and R 3 R 4 and R 5 each independently may be hydrogen or a substituent selected from deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and / or combinations thereof, and Ar 5 and Ar 6 each independently may be selected from aryl, heteroaryl, and / or combinations thereof. R 3 R 4 and R 5 each independently may be hydrogen or a substituent selected from aryl, heteroaryl, and / or combinations thereof.

[0024] In embodiments of the disclosed subject matter, the device can be at least one type selected from a flat panel display, computer monitor, medical monitor, television, bulletin board, indoor or outdoor lighting and / or signal transmitting light, head-up display, fully or partially transparent display, flexible display, laser printer, telephone, mobile phone, tablet, phablet, personal digital assistant (PDA), wearable device, laptop computer, digital camera, camcorder, viewfinder, microdisplay having an active area with a main diagonal of 2 inches or less, 3-D display, virtual reality or augmented reality display, vehicle, video wall including multiple displays arranged side by side, theater or stadium screen, and billboard. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] [Figure 1] Figure 1 shows an organic light-emitting device.

[0026] [Figure 2] Figure 2 shows an inverted organic light-emitting device that does not have another electron transport layer.

[0027] [Figure 3] Figure 3 shows an exemplary device structure according to an embodiment of the disclosed subject.

[0028] [Figure 4] Figure 4 shows exemplary materials used in an OLED (organic light-emitting diode) device according to the disclosed subject matter.

[0029] [Figure 5] Figure 5 shows the energy levels of an exemplary PHOLED (phosphorescent organic light-emitting diode) structure according to the disclosed subject.

[0030] [Figure 6] Figure 6 shows a graph of external quantum efficiency (EQE) versus current density for a device having RD1 and RD2 emitters according to the disclosed subject matter.

[0031] [Figure 7] Figure 7 shows a device material according to an embodiment of the disclosed subject. [Modes for carrying out the invention]

[0032] Generally, an OLED includes at least one organic layer positioned between the anode and cathode and electrically connected to them. When an electric current is applied, the anode injects holes and the cathode injects electrons into the organic layer(s). The injected holes and electrons move to the oppositely charged electrodes, respectively. 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. Light is emitted via a photoemission mechanism when the exciton relaxes. In some cases, excitons may be localized on an excimer or exciplex. Non-radiative mechanisms such as thermal relaxation may occur, but these are generally considered undesirable.

[0033] Early OLEDs used light-emitting molecules ("fluorescent") that emitted light from their singlet state, as disclosed, for example, in U.S. Patent No. 4,769,292, which is incorporated in its entirety by reference. Fluorescence emission generally occurs within a timeframe of less than 10 nanoseconds.

[0034] More recently, OLEDs with light-emitting materials that emit light from a triplet state ("phosphorescence") have been demonstrated. See, in their entirety, Baldo et al., "Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices," Nature, Vol. 395, pp. 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, No. 3, pp. 4-6 (1999) ("Baldo-II"). Phosphorescence is described in further detail in U.S. Patent No. 7,279,704, paragraphs 5-6, which is incorporated by reference.

[0035] Figure 1 shows an organic light-emitting device 100. The figure is not necessarily to a constant scale. 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, a light-emitting 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 barrier layer 170. The cathode 160 is a composite cathode having a first conductive layer 162 and a second conductive layer 164. Device 100 can be fabricated by sequentially depositing the described layers. The properties and functions of these various layers, as well as examples of materials, are described in further detail in US7,279,704, sections 6-10, which are incorporated by reference.

[0036] Further examples are available for each of these layers. For example, flexible and transparent substrate-anode combinations are disclosed in U.S. Patent No. 5,844,363, which is incorporated in its entirety by reference. An example of a p-doped hole transport layer is m-MTDATA doped with F4-TCNQ in a 50:1 molar ratio, as disclosed in U.S. Patent Application Publication 2003 / 0230980, which is incorporated in its entirety by reference. Examples of luminescent and host materials are disclosed in Thompson et al., U.S. Patent No. 6,303,238, which is incorporated in its entirety by reference. 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 2003 / 0230980, which is incorporated in its entirety by reference. U.S. Patents 5,703,436 and 5,707,745, which are incorporated in their entirety by reference, disclose examples of cathodes including composite cathodes having a thin layer of metal such as Mg:Ag with a transparent, conductive, sputtered-deposited ITO layer covering it. The theory and use of blocking layers are described in more detail in U.S. Patents 6,097,147 and U.S. Patent Application Publication 2003 / 0230980, which are incorporated in their entirety by reference. An example of an injection layer is provided in U.S. Patent Application Publication 2004 / 0174116, which is incorporated in its entirety by reference. A description of a protective layer can be found in U.S. Patent Application Publication 2004 / 0174116, which is incorporated in its entirety by reference.

[0037] Figure 2 shows an inverted OLED 200. 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 fabricated by depositing the described layers in order. The most common OLED configuration has a cathode positioned above the anode, and since device 200 has a cathode 215 positioned below the anode 230, device 200 can be referred to as an "inverted" OLED. The same materials described for device 100 may be used in the corresponding layers of device 200. Figure 2 provides an example of how some layers may be omitted from the structure of device 100.

[0038] The simple layered structures illustrated in Figures 1 and 2 are provided as non-limiting examples, and it is understood that embodiments of the present invention may be used in relation to a wide variety of other structures. The specific materials and structures described are substantially illustrative, and other materials and structures may be used. Functional OLEDs may be realized by combining the various layers described in various ways, or layers may be omitted entirely based on design, performance, and cost factors. Other layers not specifically described may also be included. Materials other than those specifically described may be used. Many of the examples provided herein describe various layers as containing a single material, but it is understood that combinations of materials, such as host and dopant mixtures, or more generally, mixtures, may be used. Furthermore, 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, the hole transport layer 225 transports holes and injects them into the light-emitting layer 220, and may be described as a hole transport layer or hole injection layer. In one embodiment, an OLED may be described as having an “organic layer” positioned between the cathode and the anode. The organic layer may consist of a single layer or may further consist of multiple layers of different organic materials, for example, as described with respect to Figures 1 and 2.

[0039] Structures and materials not specifically described may be used, such as OLEDs (PLEDs) composed of polymer materials, as disclosed in U.S. Patent No. 5,247,190 by Friend et al., which is incorporated in whole by reference. Further examples include OLEDs having a single organic layer. OLEDs may be stacked, for example, as described in U.S. Patent No. 5,707,745 by Forrest et al., which is incorporated in whole by reference. OLED structures may deviate from the simple layered structures illustrated in Figures 1 and 2. For example, the substrate may include angled reflective surfaces to improve outcoupling, such as a mesa structure described in U.S. Patent No. 6,091,195 by Forrest et al., which is incorporated in whole by reference, and / or a recessed structure described in U.S. Patent No. 5,834,893 by Bulovic et al.

[0040] In some embodiments disclosed herein, light-emitting layers or materials such as light-emitting layer 135 and light-emitting layer 220 shown in Figures 1 and 2, respectively, may include quantum dots. Unless otherwise indicated expressly or by context as understood by those skilled in the art, “light-emitting layer” or “light-emitting material” disclosed herein may include organic light-emitting materials and / or light-emitting materials that include quantum dots or equivalent structures. Such light-emitting layers may include only quantum dot materials that convert light emitted by another light-emitting material or other light emitter, or they may also include the other light-emitting material or other light emitter, or they may emit light itself directly from the application of an electric current. Similarly, color conversion layers, color filters, upconversion layers or structures, or downconversion layers or structures may include materials that include quantum dots, but such layers may not be considered “light-emitting layers” as disclosed herein. Generally, an "emissive layer" or material emits initial light and does not emit initial light within the device, but can be converted by other layers such as color filters or other color conversion layers that can re-emit light with a different spectral content based on the initial light emitted by the emissive layer.

[0041] Unless otherwise specified, any of the layers of the various embodiments may be deposited by any suitable method. For organic layers, preferred methods include deposition by thermal deposition, such as those described in U.S. Patent Nos. 6,013,982 and 6,087,196, which are incorporated by reference; inkjet deposition; organic vapor deposition (OVPD), such as those described in U.S. Patent No. 6,337,102 by Forrest et al., which are incorporated by reference; and organic vapor jet printing (OVJP), such as those described in U.S. Patent No. 7,431,968, which are incorporated by reference. Other suitable deposition methods include spin coating and other solution-based processes. Solution-based processes are preferably carried out in a nitrogen or inert atmosphere. For other layers, preferred methods include thermal deposition. Preferred patterning methods include those described in U.S. Patents No. 6,294,398 and No. 6,468,819, which are incorporated in whole by reference, as well as patterning related to several deposition methods such as inkjet and OVJD. Other methods may be used. The material to be deposited may be modified to suit a particular deposition method. For example, substituents such as alkyl and aryl groups, which are branched or unbranched and preferably contain at least three carbon atoms, may be used in small molecules to enhance their ability to undergo solution processing. Substituents with 20 or more carbon atoms may be used, with 3 to 20 carbon atoms being a preferred range. Materials with asymmetric structures may have better solution processability than those with symmetric structures because asymmetric materials may be less prone to recrystallization. Dendrimer substituents may be used to enhance the ability of small molecules to undergo solution processing.

[0042] Devices fabricated according to embodiments of the present invention may further include a barrier layer. One purpose of the barrier layer is to protect the electrodes and organic layers from damaging exposure to harmful species in the environment, including moisture, vapors and / or gases. The barrier layer may be deposited on, below, or next to the substrate, electrodes, or on any other part of the device, including edges. The barrier layer may consist of a single layer or multiple layers. The barrier layer may be formed by various known chemical vapor deposition techniques and may include single-phase and multi-phase compositions. Any suitable material or combination of materials may be used for the barrier layer. The barrier layer may incorporate inorganic or organic compounds or both. Preferred barrier layers include mixtures of polymer and non-polymer materials, as described in U.S. Patent No. 7,968,146, PCT Patent Application No. PCT / US2007 / 023098 and PCT / US2009 / 042829, which are incorporated herein by reference in their entirety. For a mixture to be considered a "mixture," the polymer and non-polymer materials, including the barrier layer, should be deposited under the same reaction conditions and / or simultaneously. The weight ratio of the polymer material to the non-polymer material can be in the range of 95:5 to 5:95. The polymer and non-polymer materials may be made from the same precursor material. In one example, the mixture of polymer and non-polymer materials essentially consists of polymer silicon and inorganic silicon.

[0043] Devices fabricated according to embodiments of the present invention can be incorporated into a wide variety of electronic component modules (or units) that can be incorporated into various electrical products or intermediate components. Such electrical products or intermediate components include display screens and lighting devices (such as discrete light source devices or lighting panels) that can be used by end-user product manufacturers. Such electronic component modules may optionally include drive electronics and / or power supplies. Devices fabricated according to embodiments of the present invention can be incorporated into a wide variety of consumer products having one or more incorporated electronic component modules (or units). A consumer product is disclosed that includes an OLED in which the organic layer of the OLED contains the compounds of the present disclosure. Such a consumer product includes any type of product that includes one or more light sources and / or one or more of the following types of display devices. Some examples of such consumer products include flat panel displays, computer monitors, medical monitors, televisions, billboards, indoor or outdoor lighting and / or signal transmission lights, head-up displays, fully or partially transparent displays, flexible displays, laser printers, telephones, mobile phones, tablets, phablets, personal digital assistants (PDAs), wearable devices, laptop computers, digital cameras, camcorders, viewfinders, microdisplays (displays less than 2 inches diagonally), 3-D displays, virtual reality or augmented reality displays, vehicles, video walls including multiple displays arranged side-by-side, theater or stadium screens, and billboards. Devices manufactured according to the present invention can be controlled using various control mechanisms, including passive matrices and active matrices. Many of the devices are intended for use within a human-comfortable temperature range, such as 18°C ​​to 30°C, more preferably room temperature (20°C to 25°C), but can also be used outside this temperature range, for example, -40°C to +80°C.

[0044] The materials and structures described herein may have applications in devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors may use these materials and structures. More generally, organic devices such as organic transistors may use these materials and structures.

[0045] Embodiments of the disclosed subject matter can provide an organic light-emitting diode (OLED) having an anode, a cathode, a light-emitting layer disposed between the anode and the cathode, and a hole-blocking layer disposed between the light-emitting layer and the cathode. The light-emitting layer may include a phosphorescent dopant. The phosphorescent dopant may have emission having a peak maximum wavelength of 600 nm or more at room temperature in a thin film doped with 0.5% PMMA (poly(methyl methacrylate)). The energy of the highest occupied molecular orbital (HOMO) of the phosphorescent dopant may be -5.1 eV or less, and the energy of the HOMO of the hole-blocking layer may be at least 0.1 eV lower than the energy of the HOMO of the phosphorescent dopant. In some embodiments, the OLED may have the hole-blocking layer disposed on top of the light-emitting layer.

[0046] The peak maximum wavelength of the phosphorescent dopant can be 610 nm or higher, 620 nm or higher, 630 nm or higher, 650 nm or higher, 700 nm or higher, 750 nm or higher, or 800 nm or higher.

[0047] The HOMO energy of the phosphorescent dopant may be -5.2 eV or less, -5.3 eV or less, or -5.4 eV or less. 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.

[0048] The positive hole blocking layer can be one or more of the following, including the compound of Formula I.

Chemical formula

[0049] The compound of formula I can be one or more of the following: [ka]

[0050] In some embodiments, the compound of formula I can be one or more of the following: [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]

[0051] The phosphorescent dopant can emit light from a triplet excited state to a ground singlet state in the device at room temperature. The phosphorescent dopant may be a metal-coordinate complex having a metal-carbon bond. The metal may be Ir, Os, Pt, Pd, Ag, Au, or Cu. The metal-coordinate complex may contain ligands having chemical moieties of pyridazine, pyrimidine, pyrazine, and / or triazine. The metal-coordinate complex may be M(L 1 ) x (L 2 ) y (L 3 ) z It can have the formula, L 1 , L 2 , and L 3 x and z may be the same or different, x is 1, 2, or 3, y is 0, 1, or 2, z is 0, 1, or 2, x+y+z is the oxidation state of the metal M, L 1 , L 2 , and L 3 Each of these can be selected independently from the following options: [ka] [ka] L 2 and L 3 Also, see below: [ka] It can be Y 1 ~Y 13 These are independently selected from carbon and nitrogen, and Y' is 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 It may be at least one of R e and R fThese may optionally condense or bond to form a ring, R a , R b , R c , and R d Each of these may independently represent the maximum number of possible substitutions from mono-substitutions, or they may represent no substitutions, R a , R b , R c , R d , R e , and R f Each is independently selected from hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphinol, and combinations thereof, R a , R b , R c , and R d Any two adjacent substituents can optionally condense or bond to form a ring or a polydentate ligand.

[0052] The aforementioned metal coordination complex is 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 ) can have the formula, L A , L B , and L C These are different from each other. The metal coordination complex is Pt(L A )(L B ) can have the formula, L A and L B They can be the same or different, L A and L B These elements may optionally combine to form a tetradentate ligand.

[0053] The aforementioned metal coordination complex is Ir(L A )2(L C ) can have the formula, L A The following can be selected. [ka] L C The following: [ka] And R A and R B Each of these may independently represent either the maximum number of possible substitutions from a mono-substitution or the absence of substitutions. A and R B Each of these may be independently selected from hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphinol, and combinations thereof. A and R B Any two adjacent substituents may optionally condense or bond to form a ring, or form a polydentate ligand.

[0054] In some embodiments, the metal coordination complex can be selected from the following: [ka] [ka] [ka] [ka] [ka]

[0055] The metal-coordinated complex may be a Pt complex having a tetradentate ligand. The tetradentate ligand may have four coordinating atoms selected from (two anionic C, two neutral N); (one anionic C, one carbene C, one neutral N, and one anionic N); (two anionic C, one carbene C, one neutral N); (one anionic C, one anionic N, two neutral N); (one anionic C, one anionic O, two neutral N); (two carbene C, two anionic N).

[0056] The electron blocking layer may contain the compound of formula II. [ka] In the formula, R 3 , R 4 , and R 5 Each of these may independently represent the maximum permissible substitution from the mono, or it may represent no substitution at all, R 3 , R 4 , and R 5 Each of these may independently be hydrogen, or a substituent selected from deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphinol, and / or combinations thereof, Ar 5 and Ar 6 Each of these may be independently selected from aryl, heteroaryl, and / or combinations thereof. 3 , R 4 , and R 5 Each of these can independently be a hydrogen atom or a substituent selected from aryl, heteroaryl, and / or combinations thereof.

[0057] The electron blocking layer may contain a compound selected from the following: [ka] [ka] [ka]

[0058] In some embodiments, the OLED has one or more properties selected from the group consisting of being flexible, rollable, foldable, stretchable, and bendable. In some embodiments, the OLED is transparent or translucent. In some embodiments, the OLED further includes a layer containing carbon nanotubes.

[0059] In some embodiments, the OLED further includes a layer containing a delayed fluorescence emitter. In some embodiments, the OLED includes an RGB pixel array or a white and color filter pixel array. 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 an illumination panel.

[0060] In some embodiments of the light-emitting region, the light-emitting region further includes a host.

[0061] In some embodiments, the compound may be a luminescent dopant. In some embodiments, the compound may generate luminescence via phosphorescence, fluorescence, thermally activated delayed fluorescence (TADF, also known as type E delayed fluorescence), triplet-triplet annihilation, or a combination of these processes.

[0062] The OLEDs disclosed herein can be incorporated into one or more consumer products, electronic component modules, and lighting panels. The organic layer may be an emissive layer, and in some embodiments, the compound may be an emissive dopant, and in other embodiments, the compound may be a non-emissive dopant.

[0063] The organic layer may also contain a host. In some embodiments, two or more hosts are preferred. In some embodiments, the host used may be a) a bipolar material, b) an electron transport material, c) a hole transport material, or d) a wide bandgap material with little to no charge transport role. In some embodiments, the host may contain a metal complex. Combination with other materials

[0064] Materials described herein as useful for specific layers in organic light-emitting devices may be used in combination with a wide variety of other materials present in the device. For example, the light-emitting dopants disclosed herein may be used in combination with a wide variety of hosts, transport layers, blocking layers, injection layers, electrodes, and other possible layers. The materials described or referenced below are non-limiting examples of materials that may be useful in combination with the compounds disclosed herein, and those skilled in the art can easily consult the literature to identify other materials that may be useful in combination.

[0065] Various materials can be used for the various luminescent and non-luminescent layers disclosed herein, as well as for their arrangement. Examples of preferred materials are disclosed in U.S. Patent Application No. 2017 / 0229663, the entirety of which is incorporated by reference. Conductive dopants:

[0066] Charge transport layers are doped with conductive dopants, significantly altering the density of charge carriers and thereby changing their conductivity. Conductivity is increased by generating charge carriers in the matrix material or, depending on the type of dopant, and changes in the Fermi level of the semiconductor can also be achieved. Hole transport layers can be doped with p-type conductive dopants, while n-type conductive dopants are used in electron transport layers. HIL / HTL:

[0067] 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 typically used as a hole injection / transport material. EBL:

[0068] An electron blocking layer (EBL) can be used to reduce the number of electrons and / or excitons emitted from the light-emitting layer. The presence of such a blocking layer in a device can result in significantly higher efficiency and / or a longer lifetime compared to a similar device lacking a blocking layer. A blocking layer can also be used to restrict light emission to a desired region 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 light-emitting element 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 embodiment, the compound used in the EBL contains the same molecule or the same functional group as one of the hosts described below. host:

[0069] 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 include a host material using the metal complex as a dopant material. The host material is not particularly limited, and any metal complex or organic compound can be used as long as the triplet energy of the host is greater than that of the dopant. Any host material can be used with any dopant as long as the triplet criterion is met. HBL:

[0070] A hole blocking layer (HBL) can be used to reduce the number of holes and / or excitons emitting from the light-emitting layer. The presence of such a blocking layer in a device can result in significantly higher efficiency and / or a longer lifetime compared to a similar device lacking a blocking layer. A blocking layer can also be used to restrict light emission to a desired region of the OLED. In some embodiments, the HBL material has a lower HOMO (further away from the vacuum level) and / or a higher triplet energy than the light-emitting material closest to the HBL interface. In some embodiments, the HBL material has a lower HOMO (further away from the vacuum level) and / or a higher triplet energy than one or more hosts closest to the HBL interface. ETL:

[0071] An electron transport layer (ETL) may include a material capable of transporting electrons. The electron transport layer may be intrinsic (undoped) or doped. Doping can 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 for electron transport. Charge Generation Layer (CGL)

[0072] In tandem or stacked OLEDs, the transport layer (CGL) plays a crucial role in performance, consisting of an n-doped layer and a p-doped layer for electron and hole injection, respectively. Electrons and holes are supplied from the CGL and electrodes. The consumed electrons and holes in the CGL are refilled by electrons and holes injected from the cathode and anode, respectively, after which the bipolar current gradually stabilizes. Typical CGL materials include n-type and p-type conductive dopants used in the transport layer. experiment

[0073] A deep HOMO emitter can be a PHOLED (phosphorescent organic light-emitting diode) emitter with a narrow spectrum, a high LE / EQE (luminescence efficiency / external quantum efficiency) ratio, a long lifetime, and an EQE value exceeding a predetermined amount. For example, the narrow spectrum of the deep HOMO emitter can have a full width at half maximum (FHWM) value of less than 50 nm, less than 45 nm, or less than 40 nm. Due to the narrow electroluminescence (EL) spectrum, the amount of photon emission in the invisible range above 670 nm can be minimized compared to conventional wide red emitters, thus reducing photon loss. Most of the emitted photons can be in the visible range, providing higher luminance efficiency at the same EQE in a narrow EL emitter.

[0074] Many narrow EL emitters can have a deeper HOMO level (e.g., about -5.3 eV) compared to the HOMO level of a wide emitter (e.g., about -5.1 eV). This can lead to different behavior of the emitter within a device. Embodiments of the subject disclosed can provide different approaches for constructing efficient device structures for deep HOMO emitters, such as deep HOMO red emitters.

[0075] Many families of deep HOMO emitters can possess desirable PHOLED performance with a narrow spectrum, high LE / EQE ratio, long lifetime, and potentially very high EQE. Due to the narrow EL spectrum, the amount of photon emission in the invisible range above 670 nm can be minimized compared to conventional broad red emitters, resulting in less photon loss. Since most of the emitted photons can be in the visible range, higher luminance efficiency can be provided at the same EQE in narrow EL emitters.

[0076] Many narrow electroluminescent (EL) emitters can have a deeper HOMO level (e.g., approximately -5.3 eV) compared to the HOMO level of broad emitters (e.g., approximately -5.1 eV). This can lead to different behavior of the emitter within the device and allow for the use of different device constructions for deep HOMO emitters.

[0077] In addition to narrow red emitters, there may be a family of green emitters with desirable performance and a deep HOMO (e.g., >5.2 eV), and similar device constructions can be used.

[0078] Embodiments of the disclosed subject matter provide efficient device structure designs for deep HOMO emitters. Differences in device properties may exist between emitter RD1 and emitter RD2 in the same device structure (e.g., as shown in Figure 6 and Table 2). These differences can be attributed to the location of the recombination region (RZ) in the EML. The hole blocking layer (HBL) can affect the efficiency of the deep HOMO RD1 emitter device, while the electron blocking layer (EBL) does not affect the efficiency (e.g., as shown in Examples 1, 2, 3, and 4 in Table 2). For emitter RD2, there may be no difference in device efficiency due to the HBL, but there may be differences due to the EBL (e.g., see Examples 5, 6, 7, and 8 in Table 2).

[0079] RD1 devices can have a recombination region near the HBL side of the EML (emissive layer). The HBL can improve the efficiency of the RD1 device by preventing exciton quenching and electron leakage to the ETL (electron transport layer). For the same reason, RD2 devices can have a recombination region (RZ) near the EBL, and the EBL can improve the efficiency of the device by preventing exciton quenching and hole leakage to the HTL (hole transport layer). An RD1 with a deep HOMO may have less hole trapping, thus providing improved hole transport to the HBL side of the EML. In contrast, an RD2 with a shallow HOMO may have more hole trapping and therefore may not provide sufficient hole transport through the EML. The RZ can be localized to be near the EBL.

[0080] Embodiments of the disclosed subject matter can provide a combination of deep HOMO emitter and HBL to provide improved device efficiency. Efficiency roll-off with increasing brightness can be a problem for phosphorescent devices, and reducing efficiency roll-off can be important to provide increased device efficiency at higher brightness levels. EQE roll-off is 1 mA / cm² in the same device. 2 10mA / cm for EQE 2 This can be calculated as the ratio of EQE in (see, for example, the last column of Table 2). The data in Table 2 and Figure 6 show that HBL can provide efficient roll-off reduction in the deep HOMO emitter of RD1 (see, for example, Examples 1 vs. 2 and Examples 3 vs. 4 in Table 2), and that there is no roll-off effect or only a minimal roll-off effect in devices with the RD2 emitter (see, for example, Examples 6 vs. 5 and Examples 7 vs. 8 in Table 2).

[0081] All of the example devices were under high vacuum (<10 -7The devices were fabricated by thermal deposition in Torr. The anode electrode was 1,150 Å indium tin oxide (ITO). The cathode consisted of 10 Å Liq (8-hydroxyquinoline lithium) and 1,000 Å Al. Immediately after fabrication, each device was sealed in a nitrogen glove box (<1 ppm H2O and O2) with a glass lid sealed with epoxy resin, and a moisture getter was placed in the package. The organic laminate of the device example sequentially contained, from the ITO surface outwards, a 100 Å HAT-CN (hexaazatriphenylene hexacarbonnitrile) as a hole injection layer (HIL); a 400 Å or 450 Å HTM (hole transport material) as a hole transport layer (HTL); a 50 Å EBM (electron blocking material) (if present) as an electron blocking layer (EBL); a 400 Å luminescent layer (EML) containing a red host H1 and 3% RD1 or RD2 red luminescent material; a 50 Å HBM (if present) as a hole blocking layer (HBL); and a 300 Å (with HBL) or 350 Å (without HBL) Liq (8-hydroxyquinoline lithium) doped with 35% ETM as an ETL.

[0082] Figure 3 shows a device structure according to an embodiment of the disclosed subject. 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.

[0083] Without the use of EBL, the HTL thickness was 50 Å thicker, and without HBL, the ETL thickness was 50 Å thicker. Therefore, the total device thickness remained the same, preventing distortions in device performance that could occur due to different layer thicknesses.

[0084] Table 1 shows the thickness and material of the device layer. The chemical structure of the device material is shown in Figure 4. [ka]

[0085] During manufacturing, the devices were tested for EL and JVL (current density, voltage, and brightness). The device performance data is summarized in Table 2. [ka]

[0086] To understand the device's performance, the HOMO-LUMO and T1 energy levels of the material were used. Energy levels were determined by solution cyclic voltammetry and differential pulsed voltammetry. Measurements were performed using a CH instrument model 6201B potentiostat with anhydrous dimethylformamide solvent and tetrabutylammonium hexafluorophosphate as the supporting electrolyte. Glassy carbon, platinum wire, and silver wire were used as the working electrode, counter electrode, and reference electrode, respectively. The electrochemical potential was measured by the peak potential difference from differential pulsed voltammetry, with reference to the internal ferrocene-ferrocenium redox pair (Fc / Fc+). The corresponding highest occupied molecular orbital (HOMO) energy and lowest unoccupied molecular orbital (LUMO) energy were determined by referencing the redox potentials of the cation and anion relative to ferrocene (4.8 eV vs. vacuum). That is, HOMO = -(CV ox) - 4.8(eV) LUMO = -(CV red) - 4.8(eV)

[0087] To determine the T1 level, less than 1 mg of the substance was dissolved in 2 mL of 2-methyltetrahydrofuran solvent by sonication. The solution was filtered through a 2-micron filter into a quartz tube. The tube was sealed with a rubber septum, and bubbles were removed with nitrogen to prevent oxygen quenching. Phosphorescence spectroscopy was performed using a Horiba Jobin Yvon Fluorolog-3 system equipped with a xenon lamp at a low temperature of around 77 K. T1 was determined using PL at 77 K. That is, T1(eV)=1240 / triplet wavelength [nm]

[0088] The HOMO-LUMO levels and T1 levels are shown in Table 3 below, and Figure 5 shows the HOMO-LUMO levels of the device material according to the disclosed subject matter. [ka]

[0089] The calculated energy levels for HBM are shown below and may have similarities to those of compound H. [ka]

[0090] There may be differences in the device properties between emitters RD1 and RD2 within the same device structure (see, for example, Figure 6 and Table 2), which can be based on the location of the recombination region (RZ) in the EML. The HBL can affect the efficiency of the RD1 emitter device with a deep HOMO, while the EBL cannot affect the efficiency (see, for example, Examples 1, 2, 3, and 4 in Table 2).

[0091] In contrast, in the reference light 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, for example, Examples 5, 6, 7, and 8 shown in Table 2). The RD1 device may have a recombination region near the HBL side of the EML, and the HBL can improve the efficiency of the RD1 device by preventing exciton loss and electron leakage to the ETL. If the RD2 device has a recombination region RZ near the EBL, the EBL can improve the efficiency of the device by preventing exciton loss and hole leakage to the HTL.

[0092] A deep HOMO RD1 can exhibit less hole capture and / or improved hole transport, and can provide a greater number of excitons near the cathode side of the EML. In contrast, a shallow reference HOMO RD2 exhibits stronger hole capture and / or less hole transport through the EML, and can provide a localized RZ near the EBL. In embodiments of the disclosed subject, the combination of a deep HOMO emitter and HBL can provide the desired device efficiency.

[0093] Efficiency roll-off with increasing brightness can be a problem for phosphorescent devices. Reducing efficiency roll-off can provide higher device efficiency at higher brightness levels. EQE roll-off was calculated as the ratio of EQE at 10 mA / cm2 to EQE at 1 mA / cm2 in the same device (see, e.g., the last column in Table 2). The data in Table 2 and Figure 6 show that HBL provides efficient roll-off reduction in deep HOMO emitters of RD1 (see, e.g., Examples 1 vs. 2 and Examples 3 vs. 4 in Table 2), with no or minimal roll-off effect in devices with RD2 emitters (see, e.g., Examples 6 vs. 5 and Examples 7 vs. 8 shown in Table 2).

[0094] The hole transport layer (HTM) can have good hole transport properties (e.g., HOMO 5.16 eV). The electron blocking layer (EBL) can have a shallow LUMO level (e.g., 1.84 eV) to prevent electron leakage to the HTL, a sufficiently high T1 energy (e.g., 452 nm) to prevent exciton leakage from the EML to the HTL, and reasonable hole transport properties (e.g., HOMO 5.38 eV).

[0095] In embodiments of the disclosed subject matter, the T1 of the EBL may be higher than the T1 of the emitter. In the absence of an emitter having a shallower HOMO level, the host (host 1) can provide electron transport via the EML (e.g., LUMO 2.88 eV) and hole transport (e.g., HOMO 5.43 eV). Embodiments of the disclosed subject matter may include one or more hosts (e.g., a single host, two hosts, etc.).

[0096] For example, shallow HOMO emitters such as RD2 (HOMO 5.05eV) can provide more hole trapping, while deep HOMO emitters such as RD1 (HOMO 5.32eV) can provide more hole transport through the EML. This allows the recombination region in the EML to be shifted depending on the emitter. In the case of deep HOMO emitters, the recombination region can be shifted toward the HBL. The HBL effect on device efficiency can be more pronounced with deep HOMO emitters such as RD1. Since RD2 can provide more hole trapping, thereby reducing hole transport through the EML, RZ can be shifted toward the EBL interface. EBL can affect the efficiency of RD2 emitter devices.

[0097] For a deep HOMO emitter, the HOMO can be in the range of 5.1eV to 5.6eV, more preferably in the range of 5.15eV to 5.55eV, and even more preferably in the range of 5.2eV to 5.5eV.

[0098] Hole trapping can be a function of the emitter-host HOMO energy gap. The emitter-host HBL energy gap can be less than 0.15 eV. Hole blocking materials (HBMs) can have a deep HOMO (5.96 eV), thereby blocking holes from leaking into the ETL, and have a high T1 energy (e.g., 484 nm), which can prevent exciton leakage into the ETL. In embodiments of the disclosed subject matter, the HBL can have a HOMO level deeper than 5.5 eV.

[0099] ETM can provide electron transport from ETL to EML (e.g., LUMO 2.71eV).

[0100] The combination of deep HOMO emitter R1 and HBL in the disclosed subject device and / or structure can provide increased efficiency, minimized efficiency roll-off, and increased power efficiency.

[0101] Embodiments of the subject matter disclosed can provide the following types of red light emitters having a deep HOMO. [ka]

[0102] The embodiments of the subject disclosed can provide a deep HOMO red ligand structure for luminescent ligands. [ka] [ka] CF3-containing auxiliary ligands can provide a deeper HOMO. [ka] The above can be combined with one or more other luminescent ligands to shift the HOMO by 0.1eV to 0.15eV (or more, if there are multiple CF3 ligands).

[0103] In some embodiments, the OLED may include at least one light-emitting element selected from the group of light-emitting elements shown below. [ka] [ka] [ka] [ka] [ka] [ka]

[0104] Additional device data is obtained, and a class of compound blocking layer materials and hosts that can provide improved performance for deep HOMO red emitter devices with blocking layers is shown. In devices with deep HOMO emitter RD1 and shallow HOMO emitter RD2, two hosts, a single host 1, and two hosts 2:host 3 (4:1), as well as three blocking layer materials (e.g., HBL1, HBL2, HBL3) were used. Both emitters have approximately the same chroma but different types of energy levels.

[0105] The manufacturing of the device is the same as described above, and Figure 7 shows the device material according to the disclosed subject matter.

[0106] The experimental data is summarized in Table 4 below, showing the correlation between the blocking layer and the device EQE in the device. [ka]

[0107] The EQE of a device with a deep HOMO RD1 emitter can be influenced by the blocking layer (BL), and can be about 10% higher than that of a device without a BL. For a single host, the EQE of a blocking layer structure can be about 20%, as shown in Examples 9, 10, and 11. In contrast, Example 12 shows that a reference structure without a BL can have an EQE of about 18%.

[0108] Devices in two hosts with a deep HOMO emitter in RD1 can similarly be affected by the BL. In Examples 13, 14, and 15, the BL structure has an EQE of approximately 24%. In Example 16, a device without a BL structure can have an EQE of approximately 22%.

[0109] The EQE of a device having a shallow HOMO emitter in RD2 may not be affected by the HBL. In single-host examples 17, 18, and 19, the BL device may have an EQE similar to that of a device without a BL (e.g., Example 20, where the EQE is about 24%). The EQE of two-host devices with BLs in Examples 21, 22, and 23 may be the same as that of a device without a BL in Example 24 (e.g., about 25%).

[0110] Various classes of BL materials can be used with HOMO emitters. For example, BL1, BL2, BL3, and / or HBM can belong to the following classes of materials: aluminum quinoline complexes, aza-dibenzothiopene derivatives, indro[2,3-a]carbazole derivatives, and 4,6-disubstituted dibenzothiophenes. These various classes can function as BL materials for deep HOMO red emitters (PHOLEDs).

[0111] The energy levels of the additional host and blocking layers are shown above in Table 3. Table 3 shows the energy levels of all materials used in the device example.

[0112] The various embodiments described herein are merely examples and are not intended to limit the scope of the invention. For example, many of the materials and structures described herein can be replaced with other materials and structures without departing from the spirit of the invention. Accordingly, the claimed invention may include variations from the specific examples and preferred embodiments described herein, as will be apparent to those skilled in the art. The various theories of why the invention works are not intended to limit it. [Prior art documents] [Patent Documents]

[0113] [Patent Document 1] U.S. Patent No. 5,844,363 [Patent Document 2] U.S. Patent No. 6,303,238 [Patent Document 3] U.S. Patent No. 5,707,745 [Patent Document 4] U.S. Patent No. 7,279,704 [Explanation of Symbols]

[0114] 100 Organic Light-Emitting Devices 110 circuit boards 115 Anodes 120 Hole injection layer 125 Hole transport layer 130 electron blocking layer 135 Emitting layer 140 Hole Blocking Layer 145 Electron transport layer 150 Electron injection layer 155 Protective layer 160 Cathode 162 First conductive layer 164 Second conductive layer 170 Barrier layer 200 Inverted OLEDs, devices 210 circuit boards 215 Cathode 220 Emitting layer 225 Hole transport layer 230 anodes

Claims

1. Node and; Cathode and; A light-emitting layer disposed between the anode and the cathode; A hole blocking layer is disposed between the light-emitting layer and the cathode, An electron transport layer disposed between the hole blocking layer and the cathode, An organic light-emitting diode (OLED) having, The light-emitting layer includes a phosphorescent dopant, The phosphorescent dopant, in a thin film doped at 0.5% in PMMA (poly(methyl methacrylate)), emits light with a peak maximum wavelength of 600 nm or higher at room temperature. The energy of the highest occupied molecular orbital (HOMO) of the phosphorescent dopant is -5.1 eV or less. The HOMO energy of the hole blocking layer is at least 0.1 eV lower than the HOMO energy of the phosphor dopant. The organic light-emitting diode (OLED) is characterized by comprising a structure selected from the following group of phosphorescent dopants. 【Chemistry 1】 (RA and RB each independently represent the maximum permissible substitution from the mono, or no substitution, R A and R B are each independently substituents selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphinol, and combinations thereof. Any two adjacent substituents of R A and R B may optionally condense or bond to form a ring or a polydentate ligand. Y is either O or S.

2. The OLED according to claim 1, wherein the peak maximum wavelength of the phosphorescent dopant is 610 nm or greater.

3. The OLED according to claim 1, wherein the HOMO energy of the phosphorescent dopant is -5.2 eV or less.

4. The OLED according to claim 1, wherein the HOMO energy of the hole blocking layer is at least 0.2 eV lower than the HOMO energy of the phosphorescent dopant.

5. The OLED according to claim 1, wherein the hole blocking layer is at least one selected from the group consisting of compounds of formula I. 【Chemistry 2】 (In the formula, R １ and R ２ Each of these independently represents either the maximum permissible substitution from the object, or no substitution at all. R １ and R ２ Each of these is independently a substituent selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphinone, and combinations thereof. Y is 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 is selected from the group consisting of, Ar １ and Ar ２ are the same or different aryl groups, Ar １ ~Ar ５ Each is independently selected from the group consisting of aryls, heteroaryls, and combinations thereof. L is a linker that is directly bonded or contains at least one aromatic ring.

6. The phosphorescent dopant is a metal-coordinate complex having a metal-carbon bond, The OLED according to claim 1, wherein the metal is selected from the group consisting of Ir, Os, Pt, Pd, Ag, Au, and Cu.

7. The OLED according to claim 6, wherein the metal coordination complex comprises a ligand containing a chemical portion selected from the group consisting of pyridazine, pyrimidine, pyrazine, and triazine.

8. The aforementioned metal coordination complex is M(L １ ) ｘ (L ２ ) ｙ (L ３ ) ｚ The formula is L １ , L ２ , and L ３ They can be the same or different. x is 1, 2, or 3. y is 0, 1, or 2. z is 0, 1, or 2. x + y + z is the oxidation state of M, The aforementioned M is Ir, L １ , L ２ , and L ３ Each is independently selected from the following group: 【Transformation 3】 【Chemistry 4】 L ２ and L ３ Also, see below: 【Transformation 5】 The OLED according to claim 6, which can be. (In the formula, Y １ ~Y １３ Each is independently selected from the group consisting of carbon and nitrogen. Y' is BR ｅ , NR ｅ PR ｅ , O, S, Se, C=O, S=O, SO ２ CR ｅ R ｆ , SiR ｅ R ｆ , and GeR ｅ R ｆ Selected from the group consisting of; R ｅ and R ｆ These can optionally condense or bond to form a ring, R ａ , R ｂ , R ｃ , and R ｄ Each of these may independently represent the maximum number of possible substitutions from a mono-substitution, or it may represent no substitutions. R ａ , R ｂ , R ｃ , R ｄ , R ｅ , and R ｆ Each is independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphinol, and combinations thereof. R ａ , R ｂ , R ｃ , and R ｄ Any two adjacent substituents can optionally condense or bond to form a ring or a polydentate ligand.

9. Includes an electron blocking layer, The OLED according to claim 1, wherein the electron blocking layer comprises a compound of formula II. 【Transformation 6】 (In the formula, R ３ , R ４ , and R ５ Each of these independently represents either the maximum permissible substitution from the object, or no substitution at all. R ３ , R ４ , and R ５ Each of these is independently a substituent selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphinone, and combinations thereof. Ar ５ and Ar ６ Each is independently selected from the group consisting of aryls, heteroaryls, and combinations thereof.

10. A consumer product comprising an organic light-emitting diode (OLED), wherein the organic light-emitting diode (OLED) is Node and; Cathode and; A light-emitting layer disposed between the anode and the cathode; A hole blocking layer is disposed between the light-emitting layer and the cathode, It has, An electron transport layer disposed between the hole blocking layer and the cathode, The light-emitting layer includes a phosphorescent dopant, The phosphorescent dopant, in a thin film doped at 0.5% in PMMA (poly(methyl methacrylate)), emits light with a peak maximum wavelength of 600 nm or higher at room temperature. The energy of the highest occupied molecular orbital (HOMO) of the phosphorescent dopant is -5.1 eV or less. The HOMO energy of the hole blocking layer is at least 0.1 eV lower than the HOMO energy of the phosphor dopant. A consumer product characterized by comprising a structure selected from the following group of phosphorescent dopants. 【Transformation 7】 (RA and RB each independently represent the maximum permissible substitution from the mono, or no substitution, R A and R B are each independently substituents selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphinol, and combinations thereof. Any two adjacent substituents of R A and R B may optionally condense or bond to form a ring or a polydentate ligand. Y is either O or S.

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