Organic electroluminescence device and display device

Abstract

The application provides an organic electroluminescent device and a display device, the organic electroluminescent device comprising at least one light-emitting layer, and the at least one light-emitting layer comprising at least one phosphorescent sensitization layer, the phosphorescent sensitization layer comprising a host material, a phosphorescent sensitization agent and a narrow-spectrum fluorescent material, and the half-peak width of the narrow-spectrum fluorescent material being less than 45 nm. The application can improve the efficiency and service life of the organic electroluminescent device.

Description

Technical Field

[0001] This invention relates to an organic electroluminescent device and display device, belonging to the field of organic electroluminescence technology. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are devices that emit light through electric current. Their main characteristic comes from their emissive layer. When an appropriate voltage is applied, electrons and holes combine in the emissive layer to generate excitons, which emit light of different wavelengths depending on the characteristics of the emissive layer. Currently, emissive layer materials generally suffer from defects such as low device efficiency and short lifetime, especially in multilayer devices, which typically consist of multiple emissive layers. These emissive layers are mainly composed of a host material and a phosphorescent material, and are limited by the structural characteristics of the phosphorescent material (such as long wavelengths). 3 MLCT absorption and its own long transient lifetime can easily lead to problems such as low device efficiency and short lifespan. Summary of the Invention

[0003] This invention provides an organic electroluminescent device and display device, which can improve the device's efficiency and lifespan, and effectively overcome the defects of the prior art.

[0004] In one aspect, the present invention provides an organic electroluminescent device comprising at least one luminescent layer, wherein the at least one luminescent layer comprises at least one phosphorescent photosensitive layer, wherein the phosphorescent photosensitive layer comprises a host material, a phosphorescent photosensitive agent and a narrow-spectrum fluorescent material, wherein the full width at half maximum (FWHM) of the narrow-spectrum fluorescent material is less than 45 nm.

[0005] Optionally, the number of light-emitting layers is at least two, and the at least two light-emitting layers are stacked; and / or, the thickness of the light-emitting layer is Preferred

[0006] Optionally, it further includes an anode and a cathode, wherein the at least one light-emitting layer includes a first light-emitting layer and a second light-emitting layer, and the cathode, the first light-emitting layer, the second light-emitting layer and the anode are stacked in sequence, wherein the first light-emitting layer is the phosphorus photosensitive layer, or the second light-emitting layer is the phosphorus photosensitive layer, or both the first light-emitting layer and the second light-emitting layer are phosphorus photosensitive layers.

[0007] Optionally, the emission peak of the narrow-spectrum fluorescent material is 550nm-680nm; preferably, the emission peak of the narrow-spectrum fluorescent material is 590nm-650nm.

[0008] Optionally, the narrow-spectrum fluorescent material includes one or more compounds having the structures shown in Formula V-1, Formula V-2, and Formula V-3.

[0009] Optionally, the R 1 and R 2 For the same group; and / or, the R 3 and R 4 For the same group; and / or, the R 3 R 4 R 3X and R 4X For the same group; and / or, the R 1 and R 2 Each is independently attached to the meta position of the carbon atom to which the O atom is attached; and / or, R 3 and R 4 It is attached to the para position of the carbon atom to which the N atom is attached.

[0010] Optionally, the narrow-spectrum fluorescent material includes one or more of compounds A1 to A268.

[0011] Optionally, the host material includes one or more of compounds PH-1 to PH-85.

[0012] Optionally, the phosphorescent photosensitizer includes one or more of compounds RPD-1 to RPD-29.

[0013] Optionally, in the phosphorus photosensitive layer, the mass content of the phosphorus photosensitive agent is 0.1-50%, preferably 0.1-15%, the mass content of the narrow-spectrum fluorescent material is 0.1-30%, preferably 0.1-5%, and the balance is the main material.

[0014] In another aspect, the present invention provides a display device including the above-described organic electroluminescent device.

[0015] In this invention, at least one light-emitting layer of the organic electroluminescent device is a phosphorescent sensitization layer (i.e., at least one phosphorescent sensitization layer). The composition system of the phosphorescent sensitization layer includes a host material, a phosphorescent sensitizer, and a narrow-spectrum fluorescent material. The half-width at half maximum (FWHM) of the introduced narrow-spectrum fluorescent material is less than 45 nm. Under such a composition system, using phosphorescent material to sensitize the narrow-spectrum fluorescent material for light emission can improve the problem of the phosphorescent material itself having a wide half-width, thereby improving the device's efficiency and lifespan. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of an organic electroluminescent device according to an embodiment of the present invention;

[0017] Figure 2This is a schematic diagram of the structure of an organic electroluminescent device according to another embodiment of the present invention;

[0018] Explanation of reference numerals in the attached figures: 10: Anode; 11: First hole injection layer; 20: Cathode; 21: First hole transport layer; 22: Second hole transport layer; 31: First electron blocking layer; 32: Second electron blocking layer; 41: First light-emitting layer; 42: Second light-emitting layer; 51: First hole blocking layer; 52: Second hole blocking layer; 61: First electron transport layer; 62: Second electron transport layer; 71: p-type charge generation layer; 72: n-type charge generation layer; 81: First electron injection layer; 9: Light extraction layer. Detailed Implementation

[0019] In related technologies, light-emitting layer materials generally suffer from defects such as low device efficiency and short lifespan, especially in multilayer devices, which typically have at least two light-emitting layers. These layers are mainly composed of a host material and a phosphorescent material (or phosphorescent dye). For example, in red multilayer devices, the light-emitting layer almost always uses a host material and a red phosphorescent dye as its composition. Under such a composition, limitations arise due to the structural characteristics of the phosphorescent material (such as long wavelengths). 3 MLCTs (due to their absorption and long transient lifetime) often suffer from problems such as a wide emission peak width, resulting in low device efficiency and short lifetime.

[0020] In view of this, the present invention provides an organic electroluminescent device, such as... Figure 1 and Figure 2 As shown, the organic electroluminescent device includes at least one light-emitting layer, and the at least one light-emitting layer includes at least one phosphorescent photosensitive layer. The phosphorescent photosensitive layer includes a host material, a phosphorescent photosensitive agent, and a narrow-spectrum fluorescent material. The full width at half maximum (FWHM) of the narrow-spectrum fluorescent material is less than 45 nm.

[0021] The aforementioned organic electroluminescent device includes at least one phosphorescent sensitization layer. The phosphorescent sensitization layer consists of a host material, a phosphorescent sensitizer, and a narrow-spectrum fluorescent material. The half-width at half maximum (FWHM) of the introduced narrow-spectrum fluorescent material is less than 45 nm. Under such a composition, using phosphorescent material to sensitize the narrow-spectrum fluorescent material for luminescence can improve the problem of the phosphorescent material itself having a wide FWHM, thereby improving the device's efficiency and lifetime performance, and achieving high-efficiency and high-stability luminescence.

[0022] In some embodiments, the emission peak of the narrow-spectrum fluorescent material can be 550nm-680nm, such as 550nm, 580nm, 590nm, 600nm, 610nm, 620nm, 630nm, 640nm, 650nm, 660nm, 670nm, 680nm, etc. Preferably, the emission peak of the narrow-spectrum fluorescent material is 590-650nm, and its emission spectrum is red light, which can enable the organic electroluminescent device of this application embodiment to generate red light. As a red light device, by introducing a triple-doped system of host material, phosphorescent photosensitizer and narrow-spectrum fluorescent material to form an emitting layer, and making the FWHM of the narrow-spectrum fluorescent material less than 45nm, the efficiency and lifetime of the red light device can be improved.

[0023] Specifically, the aforementioned narrow-spectrum fluorescent material can be selected from fluorescent materials with a double boron resonance structure having an FWHM < 45 nm. For example, in some preferred embodiments, the narrow-spectrum fluorescent material includes one or more compounds having the structures shown in Formula V-1, Formula V-2, and Formula V-3 as follows:

[0024]

[0025] Among them, R 1 R 2 R 3 R 4 R 3X R 4X Each independently represents a monosubstituted to the maximum permissible substituent, and R 1 and R 2 Each is independently selected from any one of substituted or unsubstituted C1-C20 straight-chain or branched alkyl groups, substituted or unsubstituted C3-C20 cycloalkyl groups, or substituted or unsubstituted C1-C20 alkylsilyl groups, R 3 R 4 R 3X and R 4X Each is independently selected from any one of substituted or unsubstituted C6-C60 aryl groups and substituted or unsubstituted C3-C60 heteroaryl groups; or, R 1 and R 2 Each is independently selected from any one of substituted or unsubstituted C6-C60 aryl groups and substituted or unsubstituted C3-C60 heteroaryl groups, R 3 R 4 R 3X and R 4X Each is independently selected from any one of the following: substituted or unsubstituted C1-C20 straight-chain or branched alkyl groups, substituted or unsubstituted C3-C20 cycloalkyl groups, or substituted or unsubstituted C1-C20 alkylsilyl groups.

[0026] Where R 1, R 2 , R 3 , R 4 , R 3X , R 4X When having substituents (i.e., the above-mentioned groups being substituted), the substituents are each independently selected from at least one of halogen, C1-C20 straight-chain or branched-chain alkyl, C3-C20 cycloalkyl, nitro, cyano, amino, hydroxyl, C1-C20 alkylsilyl, C6-C60 aryl or C3-C60 heteroaryl, and are further preferably any one or a combination of at least two of C1-C20 straight-chain or branched-chain alkyl, C3-C20 cycloalkyl, C1-C20 alkylsilyl, C6-C60 aryl or C3-C60 heteroaryl; R 1 , R 2 , R 3 , R 4 , R 3X , R 4X are each independently not connected to the adjacent benzene ring structure or are connected into a ring through chemical bonds.

[0027] The compounds having the structures shown in Formula V-1, Formula V-2, and Formula V-3 have a diboron resonance structure. Through the synergistic effect of the parent nucleus structure and the substituents, high luminescence efficiency can be achieved based on triplet excitons, and they have excellent carrier transport efficiency. Their emission spectrum is red light, and the luminescence spectrum is narrow, with FWHM < 45 nm, which can effectively adjust and improve the light color, and improve the light color, light purity, luminescence efficiency, and lifespan and other properties of the device.

[0028] Specifically, in the molecular structure of the above narrow-spectrum fluorescent material, a part of the peripheral groups (R 1 , R 2 , R 3 , R 4 , R 3X and R 4X ) are groups with aromaticity (i.e., the above-mentioned aryl or heteroaryl), and a part are groups without aromaticity (i.e., the above-mentioned straight-chain or branched-chain alkyl, cycloalkyl, alkylsilyl), making the molecular structure asymmetric, which can adjust the light color to make the light color of the compound reach more than 620 nm; moreover, the introduction of the peripheral groups makes the carrier mobility higher, which is beneficial to reducing the voltage, and forms a more effective protection for the parent nucleus, inhibiting exciton quenching, thereby improving the efficiency and lifespan.

[0029] In the present invention, for the expression of chemical elements, unless otherwise specified, the concept of isotopes with the same chemical properties is included. For example, hydrogen (H) includes 1 H (protium), 2 H (deuterium, D), 3 H (tritium, T), etc., and carbon (C) includes 12 C, 13C, etc.

[0030] In this invention, unless otherwise specified, the heteroatom of the heteroaryl group is selected from atoms or groups of atoms in N, O, S, P, B, Si or Se, preferably N, O or S.

[0031] In this invention, the halogen can be fluorine, chlorine, bromine or iodine.

[0032] In this invention, the way the ring structure is represented by "—" indicates that the connection site between the ring structure and the substituent is any position on the ring structure where bonding can occur. Specifically, the aforementioned "substituted or unsubstituted" group can replace one substituent or multiple substituents. When there are multiple substituents (at least two), they can be the same or different substituents.

[0033] For example, R 1 R 2 R 3 R 4 R 3X R 4X The number of elements can be 1, 2, 3, or 4, etc.; when R 1 R 2 R 3 R 4 R 3X R 4X When there are multiple (≥2) substituents, the multiple (≥2) substituents are the same or different groups.

[0034] In this invention, the expression Ca to Cb represents the number of carbon atoms in the group as a to b. Unless otherwise specified, this number of carbon atoms does not include the number of carbon atoms in the substituents. For example, C1 to C20 can be C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, or C20, etc.; C3 to C20 can be C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, or C20, etc.; C3 to C60 can be C3, C4, C5, C6, C9, C10, C12, C14, C16, etc. C18, C20, C22, C24, C26, C28, C30, C32, C34, C36, C38, C40, C42, C44, C46, ​​C48, C50, C52, C54, C56, or C58, etc.; C6 to C60 can be C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, C30, C32, C34, C36, C38, C40, C42, C44, C46, ​​C48, C50, C52, C54, C56, or C58, etc.

[0035] For example, the C1 to C20 straight-chain or branched alkyl groups are selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2-methylbutyl, n-pentyl, isopentyl, neopentyl, n-hexyl, neohexyl, 2-ethylhexyl, n-octyl, n-heptyl, n-nonyl, n-decyl, etc., but are not limited thereto.

[0036] In some specific embodiments, the substituted or unsubstituted C1-C20 straight-chain or branched alkyl group is selected from one of the following groups: methyl, ethyl, n-propyl, ... * Represents the linking site of a functional group.

[0037] Specifically, C3-C20 cycloalkyl groups can include monocyclic alkyl groups or polycyclic alkyl groups, wherein a monocyclic alkyl group refers to an alkyl group containing a single ring structure, and a polycyclic alkyl group refers to a structure composed of two or more cycloalkyl groups sharing one or more carbon atoms on a ring. For example, C3-C20 cycloalkyl groups are selected from cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, etc., but are not limited thereto.

[0038] Specifically, C6-C60 aryl groups include monocyclic aryl groups and fused-ring aryl groups. Monocyclic aryl groups refer to a single phenyl or biphenyl group (i.e., the group contains at least one phenyl group; when it contains at least two phenyl groups, the phenyl groups are linked by a single bond), such as phenyl, biphenyl, and terphenyl. Fused-ring aryl groups refer to groups containing at least two aromatic rings, which are fused together by sharing two adjacent carbon atoms. Groups, such as naphthyl, anthracene, phenanthryl, indene, fluorenyl and their derivatives (9,9-dimethylfluorenyl, 9,9-diethylfluorenyl, 9,9-dipropylfluorenyl, 9,9-dibutylfluorenyl, 9,9-dipentylfluorenyl, 9,9-dihexylfluorenyl, 9,9-diphenylfluorenyl, 9,9-dinaphthylfluorenyl, spirodifluorenyl, benzo[a]fluorenyl, etc.), fluoranthyl, triphenylene, pyrene, perylene, Benzyl or tetraphenyl, etc.

[0039] In some specific embodiments, the substituted or unsubstituted C6-C60 aryl groups are selected from one of the following groups: * Represents the linking site of a functional group.

[0040] Specifically, C3-C60 heteroaryl groups include monocyclic heteroaryl groups or fused-ring heteroaryl groups. Monocyclic heteroaryl groups refer to a single heteroaryl group (aromatic heterocycle) or a biaromatic group formed by a single heteroaryl group and another aromatic group (aryl or heteroaryl) linked by a single bond. That is, a monocyclic heteroaryl group contains at least one heteroaryl group. When the molecule contains one heteroaryl group and other aromatic groups, the heteroaryl group and other aromatic groups are linked by a single bond. For example, monocyclic heteroaryl groups include pyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, furanyl, thiopheneyl, pyrroleyl, etc.; fused-ring heteroaryl groups... A group refers to a molecule containing at least one heteroaryl group and at least one aromatic group (heteroaryl or aryl), with the two sharing two adjacent atoms and being fused together. Examples include quinolinyl, isoquinolinyl, quinoxalinyl, quinazolinyl, benzofuranyl, benzothiopheneyl, isobenzofuranyl, isobenzothiopheneyl, indolyl, dibenzofuranyl, dibenzothiopheneyl, carbazoleyl and its derivatives (N-phenylcarbazoleyl, N-naphthylcarbazoleyl, benzocarbazoleyl, dibenzocarbazoleyl, indolocarbazoleyl, azacarbazoleyl, etc.), acridineyl, phenothiazinyl, phenotoxazinyl, hydrogenated acridineyl, etc.

[0041] In this invention, "each independently" means that when there are multiple subjects, they can be the same or different from each other.

[0042] Under normal circumstances, R 1 and R 2 It can be the same group, R 3 and R 4 For the same group, more preferably, R 3 R 4 R3X and R 4X They are the same group.

[0043] In addition, R 1 and R 2 Each can be independently attached to the para or meta position of the carbon atom to which the O atom is attached. Preferably, R 1 and R 2 Each atom is independently connected to the meta position of the carbon atom bonded to the O atom, which can further improve the device's efficiency and lifespan.

[0044] In addition, R 3 and R 4 It can be attached to the para position of the carbon atom to which the N atom is attached.

[0045] In some specific embodiments, the narrow-spectrum fluorescent material includes, but is not limited to, one or more of the following compounds A1 to A268:

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059] In addition, the aforementioned host material may include, but is not limited to, one or more of the following compounds PH-1 to PH-85:

[0060]

[0061]

[0062]

[0063]

[0064] In addition, the above-mentioned phosphorescent photosensitizers include, but are not limited to, one or more of the following compounds RPD-1 to RPD-29:

[0065]

[0066]

[0067] Studies show that, relatively speaking, using one or more of the above-mentioned compounds PH-1 to PH-85 as the host material and one or more of RPD-1 to RPD-29 as the phosphorescent sensitizer is more conducive to cooperating with the above-mentioned narrow-spectrum fluorescent materials, thereby further improving the efficiency and lifetime of the device.

[0068] Generally, in the above-mentioned phosphorus photosensitizing layer, the mass content of the phosphorus photosensitizer is 0.1-50%, for example, 0.1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc.; the mass content of the narrow-spectrum fluorescent material is 0.1-30%, for example, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 15%, 18%, 20%, 25%, 30%; the remainder is the main material.

[0069] Preferably, the phosphorus sensitizer in the above-mentioned phosphorus photosensitive layer has a mass content of 0.1-15%, more preferably not exceeding 10%, for example 1-10%.

[0070] Preferably, the mass content of the narrow-spectrum fluorescent material in the above-mentioned phosphorescent photosensitive layer is 0.1-5%, more preferably 0.5-2%.

[0071] The aforementioned organic electroluminescent device also includes an anode, a hole transport region, an electron transport region, and a cathode, with the light-emitting layer, hole transport region, and electron transport region positioned between the anode and the cathode.

[0072] Specifically, such as Figure 1 As shown, the above-mentioned organic electroluminescent device can be a single-layer device (or a single-emitting-layer device), that is, it has one emitting layer, and the anode, hole transport region, emitting layer, electron transport region and cathode are stacked in sequence.

[0073] Or, such as Figure 2As shown, the above-mentioned organic electroluminescent device is a stacked device, which also includes a charge generation layer (CGL) disposed between the anode and the cathode. The number of light-emitting layers is at least two, and the at least two light-emitting layers are stacked (or stacked) in sequence along the direction from the anode to the cathode. The charge generation layer is disposed between two adjacent light-emitting layers (that is, a charge generation layer is disposed between every two adjacent light-emitting layers).

[0074] Among them, at least one light-emitting layer is a phosphorescent sensitizing layer containing the above-mentioned host material, phosphorescent sensitizer and narrow-spectrum fluorescent material, and the remaining light-emitting layers can be the above-mentioned phosphorescent sensitizing layers, or the remaining light-emitting layers can be phosphorescent layers including host material and phosphorescent material but not containing the above-mentioned narrow-spectrum fluorescent material.

[0075] When the above-mentioned organic electroluminescent device contains both a phosphorescent sensitization layer and a phosphorescent layer, the host material in the phosphorescent layer and the host material in the phosphorescent sensitization layer may be the same or different, and the phosphorescent material in the phosphorescent layer and the phosphorescent sensitizer in the phosphorescent sensitization layer may be the same or different; when the light-emitting layers of the above-mentioned organic electroluminescent device are all phosphorescent sensitization layers, the host materials in different light-emitting layers may be the same or different, the phosphorescent sensitizers in different light-emitting layers may be the same or different, and the narrow-spectrum fluorescent materials in different light-emitting layers may be the same or different.

[0076] For example, the organic electroluminescent device can be a red stacked device, that is, the light-emitting layer is a red light-emitting layer, that is, multiple (at least two) red light-emitting layers are stacked sequentially along the direction of the anode and the cathode, at least one of which is the phosphorescent sensitization layer, specifically a red phosphorescent sensitization light-emitting layer for emitting red light.

[0077] In a multilayer device, the hole transport region includes a first hole transport region disposed between the anode and the light-emitting layer closest to the anode (as described below, the first light-emitting layer), and a first electron transport region disposed between the cathode and the light-emitting layer closest to the cathode (as described below, the second light-emitting layer).

[0078] Furthermore, the charge generation layer includes an n-type charge generation layer (n-CGL) and a p-type charge generation layer (p-CGL). In adjacent n-type and p-type charge generation layers, the n-type charge generation layer is located on the side of the p-type charge generation layer away from the cathode, and the p-type charge generation layer is located on the side of the n-type charge generation layer away from the anode. The hole transport region also includes a second hole transport region, and the electron transport region also includes a second electron transport region. In the charge generation layer located between two adjacent light-emitting layers, the second electron transport region is disposed between the n-type charge generation layer and one light-emitting layer, and the second hole transport region is disposed between the p-type charge generation layer and another light-emitting layer.

[0079] Specifically, the aforementioned hole transport region (first hole transport region and second hole transport region) may include at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL). For example, it may be a single-layer hole transport layer (including a single-layer hole transport layer containing only one compound or a single-layer hole transport layer containing multiple compounds), or it may be a multilayer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0080] For example, the first hole transport region includes a hole injection layer, a hole transport layer, an electron blocking layer, and an anode, a hole injection layer, a hole transport layer, an electron blocking layer, and a light-emitting layer closest to the anode are stacked in sequence.

[0081] For example, the second hole transport region includes a hole transport layer and an electron blocking layer, with the p-type charge generation layer, hole transport layer, electron blocking layer and light-emitting layer stacked in sequence.

[0082] Specifically, the aforementioned electron transport region (first electron transport region and second electron transport region) may include at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL). For example, it may be a single-layer electron transport layer (including a single-layer electron transport layer containing only one compound or a single-layer electron transport layer containing multiple compounds), or it may be a multilayer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0083] For example, the first electron transport region includes an electron injection layer, an electron transport layer, and a hole blocking layer, with the light-emitting layer, hole blocking layer, electron transport layer, electron injection layer, and cathode being stacked sequentially closest to the cathode.

[0084] For example, the second electron transport region includes an electron transport layer and a hole blocking layer, and the light-emitting layer, the hole blocking layer, the electron transport layer and the n-type charge generation layer are stacked in sequence.

[0085] In some specific embodiments, such as Figure 1 As shown, the above-mentioned organic electroluminescent device is a single-layer device, which includes an anode 10, a first hole injection layer 11, a first hole transport layer 21, a first electron blocking layer 31, a first light-emitting layer 41, a first hole blocking layer 51, a first electron transport layer 61, a first electron injection layer 81, and a cathode 20, which are stacked in sequence.

[0086] In other specific embodiments, such as Figure 2As shown, the above-mentioned organic electroluminescent device includes two light-emitting layers, namely a first light-emitting layer 41 and a second light-emitting layer 42. The anode 10, the first light-emitting layer 41, the second light-emitting layer 42, and the cathode 20 are arranged in sequence. The first light-emitting layer 41 is a phosphorescent photosensitive layer, and the second light-emitting layer 42 is a phosphorescent layer; or, the second light-emitting layer 42 is a phosphorescent photosensitive layer, and the first light-emitting layer 41 is a phosphorescent layer; or, both the first light-emitting layer 41 and the second light-emitting layer 42 are phosphorescent photosensitive layers.

[0087] The first hole transport region between the anode 10 and the first light-emitting layer 41 includes a first hole injection layer 11, a first hole transport layer 21, and a first electron blocking layer 31. The second electron transport region between the first light-emitting layer 41 and the n-type charge generation layer 72 includes a second hole blocking layer 52 and a second electron transport layer 62. The second hole transport region between the p-type charge generation layer 71 and the second light-emitting layer 42 includes a second hole transport layer 22 and a second electron blocking layer 32. The first electron transport region between the second light-emitting layer 42 and the cathode 20 includes a first hole injection layer 11, a first hole transport layer 21, and a first electron blocking layer 31. The region includes a first hole blocking layer 51, a first electron transport layer 61, and a first electron injection layer 81. The anode 10, the first hole injection layer 11, the first hole transport layer 21, the first electron blocking layer 31, the first light-emitting layer 41, the second hole blocking layer 52, the second electron transport layer 62, the n-type charge generation layer 72, the p-type charge generation layer 71, the second hole transport layer 22, the second electron blocking layer 32, the second light-emitting layer 42, the first hole blocking layer 51, the first electron transport layer 61, the first electron injection layer 81, and the cathode 20 are stacked in sequence.

[0088] Specifically, the host material in the phosphorescent layer may include, but is not limited to, one or more of the compounds PH-1 to PH-85, and the phosphorescent material in the phosphorescent layer may include, but is not limited to, one or more of the compounds RPD-1 to RPD-29. Furthermore, the phosphorescent material in the phosphorescent layer has a mass content of 0.1-20%, for example, 0.1%, 0.5%, 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, etc., with the remainder being the host material.

[0089] Furthermore, the thickness of the aforementioned light-emitting layer (phosphorescent sensitization layer or phosphorescent layer) can be [missing information]. For example Generally preferred

[0090] Generally, the material of the n-type charge generation layer can include an organic matrix material or a mixture of an organic matrix material and a dopant material. The organic matrix material includes, for example, o-phenanthroline compounds, including but not limited to one or more of the following compounds CGL-1 to CGL-12. The dopant material can include metal compounds such as metals and / or metal salts, including but not limited to one or more of Liq, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca, Mg, Ag, and Yb.

[0091] In some specific embodiments, the mass content of the doped material in the n-type charge generation layer can be 0.1-20%, such as 0.1%, 0.5%, 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, etc., with the balance being organic matrix material.

[0092]

[0093] Furthermore, the material of the p-type charge generation layer may include, but is not limited to, one or more of the following compounds HT-1 to HT-51 and HI-1 to HI-3, such as a mixture of the first type of compounds (one or more of HT-1 to HT-51) and the second type of compounds (one or more of HI-1 to HI-3).

[0094] In some specific embodiments, the mass content of the second type of compound in the p-type charge generation layer is 0.1-30%, for example 0.1%, 0.5%, 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, etc., with the balance being the first type of compound.

[0095] In addition, the aforementioned organic electroluminescent device also includes a substrate. The anode can be formed on the substrate by sputtering or depositing anode material, and the remaining layers can be formed by conventional methods in the art such as vacuum thermal evaporation, spin coating, and printing, which will not be described in detail here. The substrate can be a glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. Furthermore, the substrate used for display can also have thin-film transistors (TFTs).

[0096] For example, the anode includes oxide transparent conductive materials such as indium tin oxide (or indium tin oxide, i.e., ITO), indium zinc oxide (or indium zinc oxide, i.e., IZO), tin dioxide (SnO2), zinc oxide (ZnO), and any combination thereof; the cathode material can be metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), and any combination thereof.

[0097] In some embodiments, the organic electroluminescent device described above can be a top-emitting device (or top-emitting device), and the substrate structure with an anode can be a top-emitting substrate structure conventionally used in top-emitting devices in the art. For example, the substrate structure with an anode includes an ITO layer, a silver layer, and an ITO layer stacked sequentially, and their thicknesses can be respectively...

[0098] In addition, a light extraction layer (CPL) 9 can be provided on the side of the cathode away from the anode to adjust the top-emitting microcavity and adjust the light color and efficiency of the top-emitting device.

[0099] The thickness of the light extraction layer 9 can be a conventional thickness for this type of layer in the art, for example, [missing information]. like wait.

[0100] Furthermore, the material of the light extraction layer 9 can be a conventional material for such layers in the art, including, but not limited to, one or more of the following compounds CPL-1 to CPL-3:

[0101]

[0102] Furthermore, the materials for the aforementioned hole transport region include, but are not limited to, one or more of the following compounds: phthalocyanine derivatives (such as CuPc), conductive polymers or polymers containing conductive dopants (such as polyphenylene oxide, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS)), and aromatic amine derivatives, wherein the aromatic amine derivatives include one or more of the following compounds HT-1 to HT-51:

[0103]

[0104]

[0105]

[0106] Furthermore, the material of the aforementioned hole injection layer may include, but is not limited to, one or more of the above-mentioned HT-1 to HT-51 and the following HI-1 to HI-3:

[0107]

[0108] Furthermore, the materials of the aforementioned electron blocking layer may include, but are not limited to, one or more of the aforementioned HT-1 to HT-51 and PH-47 to PH-77.

[0109] Furthermore, the material of the aforementioned electron transport layer may be one or more of the following ET-1 to ET-73:

[0110]

[0111]

[0112]

[0113]

[0114] Furthermore, the material of the aforementioned hole blocking layer may include, but is not limited to, one or more of the aforementioned ET-1 to ET-73 and PH-1 to PH-46.

[0115] In addition, the material of the electron injection layer may include, but is not limited to, one or more of LiQ, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca, Mg or Yb.

[0116] This invention also provides a display device including the aforementioned organic electroluminescent device. Specifically, the display device can be an OLED display or other display device, as well as any product or component with display function, such as a television, digital camera, mobile phone, or tablet computer, that includes the aforementioned display device. The advantages of this display device over the prior art are the same as those of the aforementioned organic electroluminescent device, and will not be repeated here.

[0117] The organic electroluminescent device of the present invention will be further described below through specific embodiments.

[0118] In the following examples, the full width at half maximum (FWHM) of the narrow-spectrum fluorescent materials used (such as A68, A84, A92, A227, A231, A232, A244, A266, etc.) is between 30 and 35 nm; the FWHM of the phosphorescent material RPD-8 is about 65 nm.

[0119] In the following examples and comparative examples, the current efficiency and L95 lifetime of the devices in each example and comparative example were measured, and the ratio of the measured current efficiency of the devices in each example and comparative example to the current efficiency of the device in Comparative Example 1 was calculated as the efficiency ratio. The results are shown in Table 1. The ratio of the measured L95 lifetime of the devices in each example and comparative example to the L95 lifetime of the device in Comparative Example 1 was calculated as the lifetime ratio. The results are shown in Table 1.

[0120] In this study, the current efficiency of the organic electroluminescent devices provided in the device embodiment and the device comparative example was measured using a digital source meter and a PR650 at the same brightness. Specifically, the voltage was increased at a rate of 0.1V per second until the brightness of the device reached 6000 cd / m². 2 At this time, the current efficiency (CE) of the device can be directly measured on the PR650.

[0121] The lifespan test of the LT95 is as follows: using a luminance meter at 10000 cd / m² 2 At a constant current, the brightness of the organic electroluminescent device decreased to 9500 cd / m² under the specified brightness. 2 The time is expressed in hours (h).

[0122] Example 1

[0123] The device in this embodiment is a top-emitting red light stacked device, and its structure is as follows: Figure 2 As shown, the preparation method is as follows:

[0124] (1) The top-emitting substrate coated with ITO conductive layer (anode) was ultrasonically treated in commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in acetone: ethanol mixed solvent, baked in a clean environment until the moisture was completely removed, cleaned with ultraviolet light and ozone, and bombarded with low-energy cation beam.

[0125] (2) Place the top-emitting substrate with the ITO conductive layer into a vacuum chamber and evacuate it to a vacuum level of less than 1×10⁻⁶. -5 Pa, HT-28 and HI-2 materials are co-deposited on the anolyte film as the first hole injection layer, with HI-2 material accounting for 3% and HT-28 material deposition rate being [missing information]. The total thickness of the vapor-deposited film (i.e., the thickness of the first hole-injection layer) is Of these, 3% is calculated as the sum of the masses of HT-24 and HI-2 materials equal to 100%, that is, the total mass of the second hole injection layer equal to 100%. All percentages mentioned below are calculated as the total mass of the corresponding functional layer equal to 100%. In addition, the total film thickness of the vapor deposition is the thickness of the corresponding functional layer formed by vapor deposition, which will not be elaborated on in detail.

[0126] (3) A first hole transport layer is vacuum-deposited on top of the first hole injection layer, using HT-28 material, at a deposition rate of [missing information]. The total thickness of the vapor-deposited film is

[0127] (4) A first electron blocking layer is vacuum-deposited on the first hole transport layer using HT-29 material at a deposition rate of [missing information]. The total thickness of the vapor-deposited film is

[0128] (5) A first luminescent layer is vacuum co-deposited on the first electron blocking layer. The first luminescent layer comprises 94% host material PH5, 5% phosphorus photosensitizer PRD8, and 1% narrow-spectrum fluorescent dye A227. Vacuum co-deposition is performed using a multi-source co-evaporation method. The evaporation rate of the host material is... The total thickness of the vapor-deposited film is

[0129] (6) A second hole-blocking layer is vacuum-deposited on top of the first light-emitting layer. The material is PH-31, and the deposition rate is [missing information]. The total thickness of the vapor-deposited film is

[0130] (7) ET-52 and ET-57 materials were vacuum co-deposited on the second hole blocking layer as the second electron transport layer, with a mass ratio of 1:1 and a deposition rate of 1 / 10000 for both materials. The total thickness of the vapor-deposited film is

[0131] (8) CGL-3 material and metallic Yb are co-deposited on the second electron transport layer as an n-type charge generation layer. The CGL-3 deposition rate is... The proportion of metallic Yb is 3%, and the total thickness is

[0132] (9) HI-2 and HT-28 materials were deposited on the n-type charge generation layer as the p-type charge generation layer. The HT-28 deposition rate was... The proportion of HI-2 is 5%, and the total thickness is

[0133] (10) A second hole transport layer was vacuum-deposited on the p-type charge generation layer using HT-28 material at a deposition rate of [missing information]. The total thickness of the vapor-deposited film is

[0134] (11) A second electron blocking layer was vacuum-deposited on top of the second hole transport layer. The material used was HT-29, and the deposition rate was [missing information]. The total thickness of the vapor-deposited film is

[0135] (12) A second luminescent layer is vacuum co-deposited on the second electron blocking layer. The second luminescent layer comprises 94% host material PH5 and 6% phosphorescent material PRD8. The deposition is performed using a multi-source co-evaporation method, with the deposition rate of the host material being [missing information]. The total thickness of the vapor-deposited film is

[0136] (13) A first hole-blocking layer is vacuum-deposited on the second light-emitting layer. The material is PH-31, and the deposition rate is [missing information]. The total thickness of the vapor-deposited film is

[0137] (14) ET-52 and ET-57 materials were vacuum co-deposited on the first hole blocking layer as the first electron transport layer, with a mass ratio of 1:1 and a deposition rate of 1 / 2 for both materials. The total thickness of the vapor-deposited film is

[0138] (15) The thickness of vacuum evaporation on the first electron transport layer is... Yb material is used as the first electron injection layer;

[0139] (16) Mg and Ag materials are vapor-deposited as cathodes on the first electron injection layer, with a mass ratio of 1:9 (i.e., Mg:Ag = 1:9), and the total vapor-deposited film thickness is...

[0140] (17) CPL-3 material was deposited on the cathode as a light extraction layer. The CPL-3 deposition rate was [missing information]. The total thickness of the vapor-deposited film is

[0141] Example 2: The only difference from Example 1 is that the second light-emitting layer is a phosphorescent layer (with the same composition as the first light-emitting layer (phosphorescent layer) in Example 1), and the first light-emitting layer is a phosphorescent layer (with the same composition as the second light-emitting layer (phosphorescent layer) in Example 1). All other conditions are the same as in Example 1.

[0142] Example 3: The only difference from Example 1 is that both the first and second emitting layers are phosphorus photosensitive layers (with the same composition as the first emitting layer (phosphorus photosensitive layer) in Example 1), and the other conditions are the same as in Example 1; the only difference between the device fabrication process in Example 3 and that in Example 1 is that in step (12), the second emitting layer is vacuum co-deposited on the second electron blocking layer. The second emitting layer includes 94% of the host material PH5, 5% of the phosphorus photosensitive agent PRD8, and 1% of the narrow-spectrum fluorescent dye A227. The deposition is performed using a multi-source co-evaporation method, and the deposition rate of the host material is... The total thickness of the vapor-deposited film is

[0143] Examples 4-12: The only difference from Example 3 is that different narrow-spectrum fluorescent materials are used in the phosphorescent photosensitive layer. The narrow-spectrum fluorescent materials used in Examples 3-12 are shown in Table 1.

[0144] Examples 13-20: The only difference from Example 3 is that the main material in the phosphorus photosensitive layer is different, as shown in Table 1. All other conditions are the same.

[0145] Examples 21-25: The only difference from Example 3 is that the type of phosphorus sensitizer in the phosphorus photosensitized layer is different, as shown in Table 1; all other conditions are the same.

[0146] Examples 26-36: The only difference from Example 3 is that the mass content of the main material, phosphorus sensitizer, and fluorescent material in the phosphorus photosensitive layer is different, as shown in Table 1. All other conditions are the same.

[0147] Examples 37-38: The only difference from Example 3 is that the composition of the first light-emitting layer and the second light-emitting layer are different, as shown in Table 1.

[0148] Example 39: The only difference from Example 3 is that the composition of the second light-emitting layer is different, as shown in Table 1.

[0149] Comparative Example 1: The difference from Example 1 is that both the first and second light-emitting layers are phosphorescent layers (with the same composition as the second light-emitting layer (phosphorescent layer) in Example 1); the other conditions are the same as in Example 1.

[0150] Comparative Example 2: The difference from Example 1 is that the device structure is a single-emitting-layer device, and its structure is as follows: Figure 1 As shown, the device includes an anode, a first hole injection layer, a first hole transport layer, a first electron blocking layer, a first light-emitting layer (phosphorescent layer), a first hole blocking layer, a first electron transport layer, a first electron injection layer, and a cathode, which are stacked in sequence. The other conditions are the same as in Example 1. The single light-emitting layer device is prepared by referring to steps (1) to (5) and (13) to (17) in Example 1, which will not be repeated here.

[0151] Comparative Example 3: The difference from Example 3 is that the composition of the first light-emitting layer and the second light-emitting layer is different, as shown in Table 1.

[0152] The structural formulas of PH'-1, RPD'-1, and A'-1 are as follows:

[0153]

[0154] The composition of the first and second light-emitting layers in Examples 1-39 and Comparative Examples 1-3, as well as the performance test results of the devices, are summarized in Table 1.

[0155] Table 1

[0156]

[0157]

[0158] * indicates that the mass ratio of the two main materials is 1:1, and the sum of the mass contents of the two main materials in the light-emitting layer is 94%. Taking "PH-41:PH-60=1:1,94%" as an example, it means that in the first light-emitting layer, the mass ratio of PH-41 to PH-60 is 1:1, and the sum of the masses of PH-41 and PH-60 is 94% of the total mass of the first light-emitting layer.

[0159] As can be seen from Table 1, compared with Comparative Example 1, the devices prepared in Examples 1-38 with at least one light-emitting layer being a phosphorescent layer have significantly improved efficiency and lifetime; compared with Comparative Example 2, the stacked devices with two light-emitting layers have more significant performance in terms of efficiency and lifetime.

[0160] Furthermore, as can be seen from Examples 1-3, devices in which both the first and second light-emitting layers are phosphorescent layers exhibit superior performance in terms of efficiency and lifespan.

[0161] Furthermore, as can be seen from Examples 3-12, devices using fluorescent materials A277, A231, A32, A244, A252, A255, and A266 (Examples 3-9) exhibit better efficiency and lifetime than devices using fluorescent materials A68, A84, and A92 (Examples 10-12). This demonstrates that when R1 and R2 substitute at the meta position of the carbon atom bonded to the O atom in the molecular structure of the fluorescent material, this type of fluorescent material exhibits superior performance when applied to multilayer devices; among them, the improvement in efficiency and lifetime is particularly significant when using A231 and A232.

[0162] Furthermore, as can be seen from Examples 26-36, when the content of the narrow-spectrum fluorescent material is in the range of 0.1-5%, more preferably 0.5-2%, and the content of the phosphorescent sensitizer is not more than 10%, the device exhibits better performance in terms of efficiency and lifetime.

[0163] As can be seen from Examples 3, 39, and Comparative Example 3, different host materials, sensitizers, and fluorescent materials affect the lifetime and efficiency of the device. In Example 3, both light-emitting layers are phosphorescent sensitizers with a half-width of less than 45 nm by introducing narrow-spectrum fluorescent materials, and are matched with specific host materials and sensitizers, exhibiting superior efficiency and lifetime performance.

Claims

1. An organic electroluminescent device, characterized in that, It includes at least one light-emitting layer, and the at least one light-emitting layer includes at least one phosphorus photosensitive layer, the phosphorus photosensitive layer includes a host material, a phosphorus photosensitive agent and a narrow-spectrum fluorescent material, the full width at half maximum (FWHM) of the narrow-spectrum fluorescent material is less than 45 nm; The emission peak of the narrow-spectrum fluorescent material is 590nm-650nm; In the phosphorescent photosensitive layer, the mass content of the narrow-spectrum fluorescent material is 0.1%-5%; In the phosphorus photosensitized layer, the mass content of the phosphorus photosensitizer is 0.1-10%; The narrow-spectrum fluorescent material includes one or more compounds having the structures shown in Formula V-1, Formula V-2, and Formula V-3 as follows: Among them, R 1 R 2 R 3 R 4 R 3X R 4X Each independently represents a monosubstituted to the maximum permissible substituent, and R 1 and R 2 Each is independently selected from any one of substituted or unsubstituted C1-C20 straight-chain or branched alkyl groups, substituted or unsubstituted C3-C20 cycloalkyl groups, or substituted or unsubstituted C1-C20 alkylsilyl groups, R 3 R 4 R 3X and R 4X Each is independently selected from any one of substituted or unsubstituted C6-C60 aryl groups or substituted or unsubstituted C3-C60 heteroaryl groups; or, R 1 and R 2 Each is independently selected from any one of substituted or unsubstituted C6-C60 aryl groups or substituted or unsubstituted C3-C60 heteroaryl groups, R 3 R 4 R 3X and R 4X Each is independently selected from any one of substituted or unsubstituted C1-C20 straight-chain or branched alkyl groups, substituted or unsubstituted C3-C20 cycloalkyl groups, or substituted or unsubstituted C1-C20 alkylsilyl groups; The R 1 and R 2 Each atom is independently attached to the meta position of the carbon atom to which the O atom is attached.

2. The organic electroluminescent device according to claim 1, characterized in that, The number of light-emitting layers is at least two, and the at least two light-emitting layers are stacked.

3. The organic electroluminescent device according to claim 1, characterized in that, The thickness of the light-emitting layer is 200Å-500Å.

4. The organic electroluminescent device according to claim 3, characterized in that, The thickness of the light-emitting layer is 300 Å-400 Å.

5. The organic electroluminescent device according to claim 1, characterized in that, It also includes an anode and a cathode. The at least one light-emitting layer includes a first light-emitting layer and a second light-emitting layer. The cathode, the first light-emitting layer, the second light-emitting layer, and the anode are arranged in sequence. The first light-emitting layer is the phosphorus photosensitive layer, or the second light-emitting layer is the phosphorus photosensitive layer, or both the first light-emitting layer and the second light-emitting layer are phosphorus photosensitive layers.

6. The organic electroluminescent device according to claim 1, characterized in that, R 1 R 2 R 3 R 4 R 3X R 4X The substituents described herein are each independently selected from at least one of halogens, C1-C20 straight-chain or branched alkyl groups, C3-C20 cycloalkyl groups, nitro groups, cyano groups, amino groups, hydroxyl groups, C1-C20 alkylsilyl groups, C6-C60 aryl groups, or C3-C60 heteroaryl groups; R 1 R 2 R 3 R 4 R 3X R 4X Each is independently independent of the adjacent benzene ring structure or is connected to form a ring through chemical bonds; And / or, the R 1 and R 2 They are the same group; And / or, the R 3 and R 4 They are the same group; And / or, the R 3 R 4 R 3X and R 4X They are the same group; And / or, R 3 and R 4 It is attached to the para position of the carbon atom to which the N atom is attached.

7. The organic electroluminescent device according to any one of claims 1-6, characterized in that, The narrow-spectrum fluorescent material includes one or more of the following compounds: A227, A229 to A268: #imgpt7# 8. The organic electroluminescent device according to any one of claims 1-6, characterized in that, The host material includes one or more of the following compounds PH-1 to PH-85: And / or, the phosphorescent photosensitizer comprises one or more of the following compounds RPD-1 to RPD-29:

9. A display device, characterized in that, Includes the organic electroluminescent device according to any one of claims 1-8.

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