Phosphorescent material, electroluminescent device and display device

Abstract

The invention relates to the technical field of display, in particular to a phosphorescent material, an electroluminescent device and a display device.The phosphorescent material comprises a heteroligand phosphorescent iridium complex, and the heteroligand phosphorescent iridium complex has the structural formula as shown in the general formula I. According to the phosphorescent material provided by the invention, the structures of the neutral ligand and the auxiliary ligand are simultaneously adjusted, so that the emission wavelength of the phosphorescent material is modulated, the efficiency roll-off can be effectively inhibited, and the problem of display color cast caused by the efficiency roll-off of an electroluminescent device adopting the phosphorescent material under high current density is solved.

Description

Phosphorescent material, electroluminescent device and display device Technical Field

[0001] The embodiments of the present disclosure relate to the field of display technology, and in particular to a phosphorescent material, an electroluminescent device, and a display apparatus. Background Art

[0002] Organic light-emitting diodes (OLEDs) offer a wide range of applications due to their advantages, including solid-state, autonomous illumination, high brightness, high resolution, wide viewing angle, fast response, thinness, compact size, light weight, flexible substrate compatibility, low-voltage DC drive, low power consumption, and a wide operating temperature range. The phosphorescent materials used in the light-emitting layer of OLED devices boast broad application prospects due to their ability to achieve the co-emission of singlet and triplet excitons, theoretically achieving 100% internal quantum efficiency and high external quantum efficiency.

[0003] Summary of the Invention

[0004] This disclosure adopts the following technical solutions:

[0005] A first aspect of the present disclosure provides a phosphorescent material, comprising:

[0006] A heteroleptic phosphorescent iridium complex having the structural formula shown in the following general formula I:

[0007] Wherein, X1 is O or S, X2 and X3 are each independently selected from N or C;

[0008] R1, R2, R3, R4, R5 and R6 are each independently selected from hydrogen, deuterium, halogen, cyano, nitro, hydroxyl, amino, sulfonic acid, sulfonyl, phosphoryl, substituted or unsubstituted C1-C60 alkyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C1-C60 alkoxy, substituted or unsubstituted C1-C60 alkylamino, substituted or unsubstituted C2-C60 alkenyl, substituted or unsubstituted C2-C60 alkynyl, substituted or unsubstituted C5-C60 heterocyclyl, substituted or unsubstituted C10-C60 fused ring or substituted or unsubstituted C5-C60 spirocyclyl.

[0009] In an optional embodiment, the exciton lifetime of the heteroleptic phosphorescent iridium complex is less than or equal to 1 μs.

[0010] In an optional embodiment, the ratio of the current efficiency of the electroluminescent device at a peak brightness of 16000 nits to the current efficiency at a peak brightness of 1300 nits is less than or equal to 0.8, and the electroluminescent device includes a light-emitting layer, and the material of the light-emitting layer includes the heteroligand phosphorescent iridium complex.

[0011] In an optional embodiment, the substitution sites of R1, R2 and R3 are at any position of their rings, R1 and R3 represent a monosubstituent, a disubstituent, a trisubstituent or no substituent, R2 and R5 represent a monosubstituent, a disubstituent or no substituent, and R4 and R6 represent a monosubstituent or no substituent.

[0012] In an optional embodiment, any adjacent R1, R2, and R3 substituents form a condensed ring or an aromatic heterocycle with the ring in which they are located, and the R1, R2, and R3 that do not form a condensed ring or an aromatic heterocycle are independently selected from any one of hydrogen, deuterium, a substituted or unsubstituted C1-C60 alkyl group, a substituted or unsubstituted C6-C60 aryl group, a substituted or unsubstituted C3-C60 cycloalkyl group, a substituted or unsubstituted C5-C60 heterocyclic group, a substituted or unsubstituted C10-C60 condensed ring group, and a substituted or unsubstituted C5-C60 spirocyclic group.

[0013] In an optional embodiment, R1, R2, R3, R4, R5 and R6 are each independently selected from any one of hydrogen, deuterium, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C5-C30 heterocyclic group, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C10-C30 condensed ring group.

[0014] In an optional embodiment, R1 is any one of tert-butyl, methyl, and hydrogen, R2 is any one of methyl, hydrogen, and deuterium, R3 is any one of hydrogen, methyl, and tert-butyl, R4 is any one of hexyl, methyl, and isopropyl, R5 is hydrogen, and R6 is any one of hexyl, methyl, and isopropyl.

[0015] In an optional embodiment, the heteroleptic phosphorescent iridium complex is selected from any one of the following complexes:

[0016] A second aspect of the present disclosure provides an electroluminescent device, comprising:

[0017] an anode, a cathode, and at least one light-emitting layer, wherein the light-emitting layer is disposed between the anode and the cathode, and the light-emitting layer comprises the phosphorescent material as described in any one of the first aspects;

[0018] The light-emitting layer includes a host light-emitting material and a guest light-emitting material, and the phosphorescent material is at least one of the host light-emitting material and the guest light-emitting material.

[0019] In an optional embodiment, the electroluminescent device comprises:

[0020] A hole injection layer, a hole transport layer, and an electron blocking layer, wherein the hole injection layer, the hole transport layer, and the electron blocking layer are sequentially arranged between the anode and the light-emitting layer along a first direction, where the first direction is the direction from the anode to the cathode;

[0021] A hole blocking layer, an electron transport layer, and an electron injection layer are sequentially arranged between the light emitting layer and the cathode along the first direction.

[0022] In an optional embodiment,

[0023] The thickness of the electron injection layer is in the range of 0.5 nm to 3 nm;

[0024] The thickness of the electron transport layer is in the range of 20 nm to 35 nm;

[0025] The thickness of the electron blocking layer is in the range of 5 nm to 80 nm;

[0026] The thickness of the light-emitting layer is in the range of 30 nm to 50 nm;

[0027] The thickness of the hole blocking layer is in the range of 5 nm to 10 nm;

[0028] The thickness of the hole transport layer is in the range of 80 nm to 130 nm;

[0029] The thickness of the hole injection layer is in the range of 5 nm to 30 nm.

[0030] In an optional embodiment, the light-emitting layer includes:

[0031] The first light-emitting layer and the second light-emitting layer, wherein the material of at least one of the first light-emitting layer and the second light-emitting layer is the phosphorescent material as described in any one of the first aspects.

[0032] In an optional embodiment, the electroluminescent device comprises:

[0033] A charge generation layer is provided between the first light-emitting layer and the second light-emitting layer, and includes a p-type charge generation layer and an n-type charge generation layer.

[0034] A hole injection layer, a first hole transport layer, and a first electron blocking layer, wherein the hole injection layer, the first hole transport layer, and the first electron blocking layer are sequentially arranged between the anode and the first light-emitting layer along a first direction, where the first direction is the direction from the anode to the cathode;

[0035] a second hole blocking layer, a second electron transport layer and an electron injection layer, wherein the second hole blocking layer, the second electron transport layer and the electron injection layer are sequentially arranged between the cathode and the second light-emitting layer along the first direction;

[0036] a first hole blocking layer, the first hole blocking layer being disposed between the first light-emitting layer and the n-type charge generation layer;

[0037] A second hole transport layer and a second electron blocking layer are sequentially arranged between the p-type charge generation layer and the second light emitting layer along the first direction.

[0038] In an optional embodiment, the electroluminescent device further comprises a first electron transport layer, wherein the first electron transport layer is disposed between the n-type charge generation layer and the first hole blocking layer;

[0039] The thickness of the electron injection layer is in the range of 0.5 nm to 3 nm;

[0040] The thickness of the first electron transport layer and the second electron transport layer is in the range of 20 nm to 35 nm;

[0041] The thickness of the first electron blocking layer and the second electron blocking layer is in the range of 5 nm to 80 nm;

[0042] The thickness of the first light-emitting layer and the second light-emitting layer is in the range of 30 nm to 50 nm;

[0043] The thickness of the first hole blocking layer and the second hole blocking layer is in the range of 5 nm to 10 nm;

[0044] The thickness of the first hole transport layer and the second hole transport layer is in the range of 80 nm to 130 nm;

[0045] The thickness of the hole injection layer is in the range of 5 nm to 30 nm;

[0046] The thickness of the p-type charge generation layer is in the range of 8 nm to 10 nm;

[0047] The thickness of the n-type charge generation layer is in the range of 17 nm to 19 nm.

[0048] A third aspect of the present disclosure provides a display device comprising the electroluminescent device as described in any one of the second aspects.

[0049] The above description is only an overview of the technical solution of the present disclosure. In order to more clearly understand the technical means of the present disclosure, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present disclosure more obvious and easy to understand, the specific implementation methods of the present disclosure are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or related technologies, the following is a brief introduction to the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0051] FIG1 schematically shows a schematic diagram of an electroluminescent device proposed in the present disclosure;

[0052] FIG2 schematically shows a current efficiency-brightness curve of an electroluminescent device proposed in the present disclosure;

[0053] FIG3 schematically shows a schematic diagram of an electroluminescent device with a stacked structure proposed in the present disclosure;

[0054] FIG4 schematically shows another electroluminescent device with a stacked structure proposed in the present disclosure.

[0055] Description of the drawings: 101, cathode; 102, electron injection layer; 103, electron transport layer; 103-1, first electron transport layer; 103-2, second electron transport layer; 104, hole blocking layer; 104-1, first hole blocking layer; 104-2, second hole blocking layer; 105, light-emitting layer; 105-1, first light-emitting layer; 105-2, second light-emitting layer; 106, electron blocking layer; 106-1, first electron blocking layer; 106-2, second electron blocking layer; 107, hole transport layer; 107-1, first hole transport layer; 107-2, second hole transport layer; 108, hole injection layer; 109, anode; 110, charge generation layer; 110-1, p-type charge generation layer; 110-2, n-type charge generation layer. Specific embodiments

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present disclosure without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0057] Organic light-emitting diodes (OLEDs) offer a wide range of applications, including solid-state, autonomous illumination, high brightness, high resolution, wide viewing angle (over 170°), fast response, thinness, compact size, light weight, flexible substrate compatibility, low-voltage DC drive (3-10V), low power consumption, and a wide operating temperature range. These advantages include: lighting systems, communications systems, automotive displays, portable electronic devices, high-definition displays, and even military applications.

[0058] Driven by the voltage of an OLED, holes are injected from the anode into the highest occupied molecular orbital (HOMO) of the organic material, while electrons are injected from the cathode into the lowest unoccupied molecular orbital (LUMO) of the organic material. The holes and electrons move separately in the organic layer and recombine upon encountering each other to produce excitons. The excitons then diffuse freely in the organic solid film and deactivate in both radiative and non-radiative forms. The excitons return from a high-energy state (excited state) to a ground state, where they are released as energy light, causing the device to emit light. During this process, the excitons must recombine in the middle of the light-emitting layer to emit light efficiently. Therefore, the injection and migration of electrons and holes in the organic material must be balanced. Improving the efficiency and extending the service life of OLED devices have long been a pursuit in the field.

[0059] Phosphorescent materials, due to their ability to achieve the co-emission of singlet and triplet excitons, can theoretically achieve 100% internal quantum efficiency (IQE) in devices. These devices also possess high external quantum efficiency (EQE) and offer broad application prospects. However, a common challenge facing most high-efficiency phosphorescent devices is the dramatic decrease in EQE with increasing brightness, known as efficiency roll-off. This efficiency roll-off in phosphorescent devices is primarily due to exciton quenching, including triplet-triplet annihilation (TTA) and exciton-polaron annihilation (TPA). Therefore, to further promote the commercialization and practical application of OLEDs, it is necessary to develop effective and universally applicable novel device structures to mitigate OLED device efficiency roll-off.

[0060] In view of this, the present disclosure provides a phosphorescent material, comprising:

[0061] A heteroleptic phosphorescent iridium complex having the structural formula shown in the following general formula I:

[0062] Wherein, X1 is O or S, X2 and X3 are each independently selected from N or C;

[0063] R1, R2, R3, R4, R5 and R6 are each independently selected from hydrogen, deuterium, halogen, cyano, nitro, hydroxyl, amino, sulfonic acid, sulfonyl, phosphoryl, substituted or unsubstituted C1-C60 alkyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C1-C60 alkoxy, substituted or unsubstituted C1-C60 alkylamino, substituted or unsubstituted C2-C60 alkenyl, substituted or unsubstituted C2-C60 alkynyl, substituted or unsubstituted C5-C60 heterocyclyl, substituted or unsubstituted C10-C60 fused ring or substituted or unsubstituted C5-C60 spirocyclyl.

[0064] It should be noted that, in the embodiments of the present disclosure, the aryl groups include but are not limited to phenyl, naphthyl, anthracenyl, acenaphthyl, indenyl, phenanthrenyl, azulenyl, pyrenyl, fluorenyl, perylenyl, spirofluorenyl, spirobifluorenyl, phenyl, triphenylenyl, benzanthryl, fluoranthenyl, phenanthrenyl, naphthacene, and indenyl.

[0065] Metal complexes typically have three types of excited states: the metal-centered electronic excited state (MC), the charge transfer excited state between the central metal ion and the ligand (MLCT), and the ligand-centered π-π* transition excited state (LC). The triplet emission from the former can be further divided into two categories: triplet transition radiation from the charge transfer between the central metal ion and the ligand (3MLCT), and mixed transition radiation from 3MLCT and triplet π electrons between ligands (3LC). For phosphorescent cyclometallated iridium complexes, the LUMO energy level is located on the neutral ligand (C^N) for both 3MLCT and 3LC transition radiation. Therefore, by varying the type or structure of the ligand (C^N), the molecule's LUMO energy level can be adjusted, thereby modulating the emission wavelength of the phosphorescent material.

[0066] Generally speaking, the emission wavelength of the heteroleptic iridium complex (C^N)2Ir(L^L) can be adjusted in two ways: by changing the structure of the ligand (C^N) to achieve the modulation of the emission wavelength of the organic phosphorescent material, and by adjusting the structure of the auxiliary ligand (L^L) (provided that the MLCT or LC triplet energy level can be higher than the triplet energy level of the auxiliary ligand, that is, the LUMO is distributed on the auxiliary ligand) to achieve the same purpose. The embodiment of the present disclosure changes the structure of the ligand (C^N) by R1, R2 and R3 and X1, X2 and X3, and changes the structure of the auxiliary ligand (L^L) by R4, R5 and R6 to achieve the modulation of the emission wavelength of the heteroleptic phosphorescent iridium complex, reduce the exciton lifetime of the heteroleptic phosphorescent iridium complex, and reduce the degree of efficiency degradation. The electroluminescent device using the heteroleptic phosphorescent iridium complex provided by the embodiment of the present disclosure has excellent color purity and brightness and extended durability.

[0067] In the embodiment of the present disclosure, the exciton lifetime of the heteroleptic phosphorescent iridium complex is less than or equal to 1 μs. The electroluminescent device using the heteroleptic phosphorescent iridium complex can effectively improve the display color deviation problem caused by the efficiency roll-off of the module panel at high current density in the later stage.

[0068] The electroluminescent device using the heteroleptic phosphorescent iridium complex described in the present disclosure as the material of the light-emitting layer has a ratio of the current efficiency at a peak brightness of 16000 nits to the current efficiency at a peak brightness of 1300 nits less than or equal to 0.8. This indicates that the electroluminescent device using the heteroleptic phosphorescent iridium complex described in the present disclosure as the material of the light-emitting layer has a small efficiency roll-off. The electroluminescent device can effectively improve the current efficiency and improve the display color shift problem caused by the efficiency roll-off. However, the electroluminescent device that does not use the heteroleptic phosphorescent iridium complex described in the present disclosure as the material of the light-emitting layer has a ratio of the current efficiency at a peak brightness of 16000 nits to the current efficiency at a peak brightness of 1300 nits greater than 0.8. At this time, the efficiency roll-off of the electroluminescent device is large. As the light-emitting brightness increases, its current efficiency will decrease significantly, resulting in the problem of display color shift.

[0069] In an optional embodiment, the substitution sites of R1, R2 and R3 are at any position of their rings, R1 and R3 represent a monosubstituent, a disubstituent, a trisubstituent or no substituent, R2 and R5 represent a monosubstituent, a disubstituent or no substituent, and R4 and R6 represent a monosubstituent or no substituent.

[0070] In an optional embodiment, any adjacent R1, R2, and R3 substituents form a condensed ring or an aromatic heterocycle with the ring in which they are located, and the R1, R2, and R3 that do not form a condensed ring or an aromatic heterocycle are independently selected from any one of hydrogen, deuterium, a substituted or unsubstituted C1-C60 alkyl group, a substituted or unsubstituted C6-C60 aryl group, a substituted or unsubstituted C3-C60 cycloalkyl group, a substituted or unsubstituted C5-C60 heterocyclic group, a substituted or unsubstituted C10-C60 condensed ring group, and a substituted or unsubstituted C5-C60 spirocyclic group.

[0071] In an optional embodiment, R1, R2, R3, R4, R5 and R6 are each independently selected from any one of hydrogen, deuterium, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C5-C30 heterocyclic group, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C10-C30 condensed ring group.

[0072] In an optional embodiment, R1 is any one of tert-butyl, methyl, and hydrogen, R2 is any one of methyl, hydrogen, and deuterium, R3 is any one of hydrogen, methyl, and tert-butyl, R4 is any one of hexyl, methyl, and isopropyl, R5 is hydrogen, and R6 is any one of hexyl, methyl, and isopropyl.

[0073] In an optional embodiment, the heteroleptic phosphorescent iridium complex is selected from any one of the following complexes:

[0074] The present disclosure provides a phosphorescent material comprising a heteroleptic phosphorescent iridium complex having the structural formula shown in the following general formula I. The phosphorescent material provided herein simultaneously modulates the structures of neutral ligands and auxiliary ligands to achieve modulation of the emission wavelength of the phosphorescent material, effectively suppressing efficiency roll-off and improving the display color shift problem caused by efficiency roll-off at high current density in electroluminescent devices using the phosphorescent material.

[0075] Based on the same inventive concept, an embodiment of the present disclosure provides an electroluminescent device. In an optional embodiment, the electroluminescent device is a top-emitting device or a bottom-emitting device. Taking a top-emitting device as an example, FIG1 schematically shows an electroluminescent device proposed in the present disclosure. As shown in FIG1 , the electroluminescent device includes:

[0076] An anode 109, a cathode 101, and at least one emitting layer (EML) 105 are provided between the anode 109 and the cathode 101. The emitting layer 105 includes a phosphorescent material as described in the embodiments of the present disclosure. Specifically, the emitting layer 105 includes a host emitting material and a guest emitting material, and the phosphorescent material is at least one of the host emitting material and the guest emitting material.

[0077] In some embodiments, the electroluminescent device includes: a hole injection layer (HIL) 108, a hole transport layer (HTL) 107 and an electron blocking layer (EBL) 106, wherein the hole injection layer 108, the hole transport layer 107 and the electron blocking layer 106 are sequentially arranged between the anode 109 and the light-emitting layer 105 along a first direction, where the first direction is the direction from the anode 109 to the cathode 101; a hole blocking layer (HBL) 104, an electron transport layer (ETL) 103, and an electron injection layer (EIL) 102, wherein the hole blocking layer 104, the electron transport layer 103 and the electron injection layer 102 are sequentially arranged between the light-emitting layer 105 and the cathode 101 along the first direction.

[0078] Among them, the hole blocking layer 104 is used to block holes from the anode 109 at the interface of the light-emitting layer 105, so as to increase the probability of recombination of electrons and holes at the interface of the light-emitting layer 105, thereby improving the luminous efficiency of the electroluminescent device; the electron blocking layer 106 is used to block electrons from the cathode 101 at the interface of the light-emitting layer 105, so as to increase the concentration of electrons at the cross section of the light-emitting layer 105.

[0079] In an optional embodiment, the anode may be a material having a high work function. For example, for a top-emitting device, the anode may be ITO (indium tin oxide), IZO (indium zinc oxide), or a composite structure of a metal and a transparent oxide (such as Ag / ITO, Ag / IZO, Al / ITO, Al / IZO, ITO / Ag / ITO, etc.).

[0080] In an optional embodiment, the cathode material may be a metal with a low work function (such as Al, Ag, Mg, etc.) or an alloy containing a metal material with a low work function.

[0081] In an optional embodiment, the material of the hole injection layer includes an inorganic oxide, a p-type dopant or a hole transport material. For example, the p-type dopant can be hexacyanohexaazatriphenylene, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), 1,2,3-tris[(cyano)(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane, etc.; the hole transport material includes any one or more of an aromatic amine hole transport material, a dimethylfluorene hole transport material or a carbazole hole transport material. Preferably, the material of the hole injection layer can be selected from any one or more of the following compounds 1 and 2:

[0082] In an optional embodiment, the hole transport layer can be formed by vacuum evaporation, and the material of the hole transport layer can be any one or more of an aromatic amine hole transport material, a dimethylfluorene hole transport material, or a carbazole hole transport material. Preferably, the material of the hole transport layer can be selected from any one or more of the following compounds 3 to 5:

[0083] In an optional embodiment, the electron blocking layer can be formed by vacuum evaporation, and the material of the electron blocking layer can be any one or more of an aromatic amine hole transport material, a dimethylfluorene hole transport material, or a carbazole hole transport material. Preferably, the material of the electron blocking layer can be selected from any one or more of the following compounds 6 and 7:

[0084] In an optional embodiment, the light-emitting layer can be formed by vacuum evaporation, the electroluminescent device is a red electroluminescent device, the material of the light-emitting layer of the red electroluminescent device includes a red light-emitting material, the red light-emitting material includes a host light-emitting material and a guest light-emitting material, and the phosphorescent material is at least one of the host light-emitting material and the guest light-emitting material. Wherein, when the guest light-emitting material is the phosphorescent material provided in the embodiment of the present disclosure, the host light-emitting material can be selected from any one or more of the following compounds 8 to 11:

[0085] In an optional embodiment, the hole blocking layer can be formed by vacuum evaporation, and the material of the hole blocking layer includes an aromatic heterocyclic compound hole blocking layer material, and the aromatic heterocyclic compound hole blocking layer material includes any one or more of a benzimidazole derivative hole blocking layer material, a triazine derivative hole blocking layer material, a pyrimidine derivative hole blocking layer material, a pyridine derivative hole blocking layer material, a pyrazine derivative hole blocking layer material, a quinoxaline derivative hole blocking layer material, a quinoline derivative hole blocking layer material, a diazole derivative hole blocking layer material, a diazaphosphole derivative hole blocking layer material, a phosphine oxide derivative hole blocking layer material, an aromatic ketone derivative hole blocking layer material, a lactam derivative hole blocking layer material, and a borane derivative hole blocking layer material. Preferably, the hole blocking layer material can be selected from any one or more of the following compounds 12 and 13:

[0086] In an optional embodiment, the electron transport layer can be formed by vacuum evaporation, and the material of the electron transport layer includes an aromatic heterocyclic compound electron transport layer material, and the aromatic heterocyclic compound electron transport layer material includes any one or more of a benzimidazole derivative electron transport layer material, a triazine derivative electron transport layer material, a pyrimidine derivative electron transport layer material, a pyridine derivative electron transport layer material, a pyrazine derivative electron transport layer material, a quinoxaline derivative electron transport layer material, a quinoline derivative electron transport layer material, a diazole derivative electron transport layer material, a diazaphosphacyclopentadiene derivative electron transport layer material, a phosphine oxide derivative electron transport layer material, an aromatic ketone derivative electron transport layer material, a lactam derivative electron transport layer material, and a borane derivative electron transport layer material. Preferably, the electron transport layer material can be selected from any one or more of the following compounds 12 to 14, and any one or more of the following compounds 15 or lithium fluoride LiF are doped therein, and the doping ratio is (4 to 6): (6 to 4):

[0087] In an optional embodiment, the electron injection layer can be formed by vacuum evaporation, and the electron injection layer includes any one or more of an alkali metal electron injection layer material or a metal electron injection layer material. For example, the material of the electron injection layer can be LiF, Yb, Mg, Ca, and compounds thereof. Preferably, the material of the electron injection layer can be any one or more of LiF, Yb, and the above-mentioned compound 15.

[0088] In an optional embodiment, the thickness of the electron injection layer is in the range of 0.5nm to 3nm; the thickness of the electron transport layer is in the range of 20nm to 35nm; the thickness of the electron blocking layer is in the range of 5nm to 80nm; the thickness of the light-emitting layer is in the range of 30nm to 50nm; the thickness of the hole blocking layer is in the range of 5nm to 10nm; the thickness of the hole transport layer is in the range of 80nm to 130nm; and the thickness of the hole injection layer is in the range of 5nm to 30nm. It should be noted that when the thicknesses of the electron injection layer, electron transport layer, electron blocking layer, light-emitting layer, hole blocking layer, hole transport layer, and hole injection layer in the electroluminescent device are within the above ranges, the color of the light emitted by the electroluminescent device varies within the same color system.

[0089] In an optional embodiment, the electroluminescent device is prepared by evaporation. For example, at 5*10 -6 Under the vacuum degree of torr, the material is evaporated on a surface with a resistance of 25Ω square by vacuum evaporation. -1 It should be noted that the above example is an optional method proposed to enable those skilled in the art to better understand the solution of the present disclosure. The specific method for preparing the electroluminescent device can be determined according to actual conditions and is not limited by the present disclosure.

[0090] In order to enable those skilled in the art to better understand the performance of the electroluminescent device provided by the embodiments of the present disclosure, the performance of the electroluminescent devices of some exemplary embodiments is tested and compared. For the embodiments (Example 1, Example 2, Example 3) and Comparative Example 1, the materials of other layers except the guest luminescent material of the light-emitting layer are any one or more of the corresponding optional materials in each layer structure described above. The guest luminescent materials of the light-emitting layers in the electroluminescent devices of Example 1, Example 2 and Example 3 are respectively the I-1 complex, I-27 complex and I-46 complex of the above-mentioned heteroleptic phosphorescent iridium complex. The guest luminescent material of the light-emitting layer in the electroluminescent device of Comparative Example 1 is the following compound:

[0091] Table 1 shows a comparison of the performance data of the electroluminescent device embodiment and the comparative example, as shown in Table 1:

[0092] Table 1 Comparison of performance data of electroluminescent device examples and comparative examples

[0093] As can be seen from the data in Table 1, the electroluminescent device using the heteroleptic phosphorescent iridium complex provided in the embodiment of the present disclosure as the guest luminescent material of the luminescent layer has a significantly improved current efficiency compared to the electroluminescent device of Comparative Example 1. Specifically, the current efficiency of Examples 1, 2, and 3 reaches above 40 cd / A, while the current efficiency of the comparative example is only 36.04 cd / A. Therefore, the electroluminescent device using the heteroleptic phosphorescent iridium complex provided in the embodiment of the present disclosure as the guest luminescent material of the luminescent layer can effectively suppress efficiency roll-off. In addition, the electroluminescent device using the heteroleptic phosphorescent iridium complex provided in the embodiment of the present disclosure as the guest luminescent material of the luminescent layer has a narrow full width at half maximum (FWHM), which can obtain phosphorescence with good color purity.

[0094] Figure 2 schematically shows a current efficiency-brightness curve of an electroluminescent device proposed in the present disclosure. As shown in Figure 2, the ordinate is the current efficiency and the abscissa is the brightness. Compared with the current efficiency-brightness curve of the electroluminescent device of Comparative Example 1, the current efficiency of the electroluminescent device of Example 2 (using I-27 complex as the guest luminescent material) decreases less with increasing brightness. Therefore, the electroluminescent device using the heteroligand phosphorescent iridium complex provided by the embodiment of the present disclosure as the guest luminescent material of the light-emitting layer can effectively suppress the efficiency roll-off.

[0095] In an optional embodiment, FIG3 schematically shows a schematic diagram of an electroluminescent device of a stacked structure proposed in the present disclosure. As shown in FIG3 , the light-emitting layer 105 includes:

[0096] The first light-emitting layer 105 - 1 and the second light-emitting layer 105 - 2 , wherein the material of at least one of the first light-emitting layer 105 - 1 and the second light-emitting layer 105 - 2 is the phosphorescent material as described in the embodiment of the present disclosure.

[0097] In some embodiments, the electroluminescent device includes: a charge generation layer 110, which is arranged between the first light-emitting layer 105-1 and the second light-emitting layer 105-2, and the charge generation layer 110 includes a p-type charge generation layer 110-1 and an n-type charge generation layer 110-2; a hole injection layer 108, a first hole transport layer 107-1 and a first electron blocking layer 106-1, and the hole injection layer 108, the first hole transport layer 107-1 and the first electron blocking layer 106-1 are sequentially arranged between the anode 109 and the first light-emitting layer 105-1 along a first direction, and the first direction is the direction from the anode 109 to the cathode 101; a second hole blocking layer 104-2, a first hole transport layer 107-1 and a first electron blocking layer 106-1. Two electron transport layers 103-2 and an electron injection layer 102, the second hole blocking layer 104-2, the second electron transport layer 103-2 and the electron injection layer 102 are arranged in sequence between the cathode 101 and the second light-emitting layer 105-2 along the first direction; the first hole blocking layer 104-1, the first hole blocking layer 104-1 is arranged between the first light-emitting layer 105-1 and the n-type charge generation layer 110-2; the second hole transport layer 107-2 and the second electron blocking layer 106-2, the second hole transport layer 107-2 and the second electron blocking layer 106-2 are arranged in sequence between the p-type charge generation layer 110-1 and the second light-emitting layer 105-2 along the first direction.

[0098] In an optional embodiment, Figure 4 schematically shows a schematic diagram of an electroluminescent device of another stacked structure proposed in the present disclosure. As shown in Figure 4, the electroluminescent device also includes a first electron transport layer 103-1, and the first electron transport layer 103-1 is arranged between the n-type charge generation layer 110-2 and the first hole blocking layer 104-1.

[0099] In an optional embodiment, the anode may be a material with a high work function. For example, for a top-emitting device, the anode may be ITO (indium tin oxide), IZO (indium zinc oxide), or a composite structure of a metal and a transparent oxide (such as Ag / ITO, Ag / IZO, Al / ITO, Al / IZO, ITO / Ag / ITO, etc.).

[0100] In an optional embodiment, the cathode material may be a metal with a low work function (such as Al, Ag, Mg, etc.) or an alloy containing a metal material with a low work function.

[0101] In an optional embodiment, the material of the hole injection layer includes an inorganic oxide, a p-type dopant, or a hole transport material. For example, the p-type dopant can be hexacyanohexaazatriphenylene, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), 1,2,3-tris[(cyano)(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane, etc.; the hole transport material includes any one or more of an aromatic amine hole transport material, a dimethylfluorene hole transport material, or a carbazole hole transport material. Preferably, the material of the hole injection layer can be selected from any one or more of the above-mentioned compounds 1 and 2.

[0102] In an optional embodiment, the first hole transport layer and the second hole transport layer can be formed by vacuum evaporation, and the material of the first hole transport layer and the second hole transport layer can be any one or more of an aromatic amine hole transport material, a dimethylfluorene hole transport material, or a carbazole hole transport material. Preferably, the material of the first hole transport layer and the second hole transport layer can be selected from any one or more of the above-mentioned compounds 3 to 5.

[0103] In an optional embodiment, the first electron blocking layer and the second electron blocking layer can be formed by vacuum evaporation, and the material of the first electron blocking layer and the second electron blocking layer can be any one or more of an aromatic amine hole transport material, a dimethylfluorene hole transport material, or a carbazole hole transport material. Preferably, the material of the first electron blocking layer and the second electron blocking layer can be selected from any one or more of the above-mentioned compounds 6 and 7.

[0104] In an optional embodiment, the first and second light-emitting layers can be formed by vacuum evaporation, the electroluminescent device is a red electroluminescent device, the material of the light-emitting layer of the red electroluminescent device includes a red light-emitting material, the red light-emitting material includes a host light-emitting material and a guest light-emitting material, and the phosphorescent material is at least one of the host light-emitting material and the guest light-emitting material. When the guest light-emitting material of at least one of the first and second light-emitting layers is the phosphorescent material provided in the embodiments of the present disclosure, the host light-emitting material can be selected from any one or more of compounds 8 to 11 above.

[0105] In an optional embodiment, the first hole blocking layer and the second hole blocking layer can be formed by vacuum evaporation, and the materials of the first hole blocking layer and the second hole blocking layer include aromatic heterocyclic compound hole blocking layer materials, and the aromatic heterocyclic compound hole blocking layer materials include any one or more of benzimidazole derivative hole blocking layer materials, triazine derivative hole blocking layer materials, pyrimidine derivative hole blocking layer materials, pyridine derivative hole blocking layer materials, pyrazine derivative hole blocking layer materials, quinoxaline derivative hole blocking layer materials, quinoline derivative hole blocking layer materials, diazole derivative hole blocking layer materials, diazaphosphole derivative hole blocking layer materials, phosphine oxide derivative hole blocking layer materials, aromatic ketone derivative hole blocking layer materials, lactam derivative hole blocking layer materials, and borane derivative hole blocking layer materials. Preferably, the materials of the first hole blocking layer and the second hole blocking layer can be selected from any one or more of the above-mentioned compounds 12 and 13.

[0106] In an optional embodiment, the first electron transport layer and the second electron transport layer can be formed by vacuum evaporation, and the materials of the first electron transport layer and the second electron transport layer include aromatic heterocyclic compound electron transport layer materials, and the aromatic heterocyclic compound electron transport layer materials include any one or more of benzimidazole derivative electron transport layer materials, triazine derivative electron transport layer materials, pyrimidine derivative electron transport layer materials, pyridine derivative electron transport layer materials, pyrazine derivative electron transport layer materials, quinoxaline derivative electron transport layer materials, quinoline derivative electron transport layer materials, diazole derivative electron transport layer materials, diazaphosphacyclopentadiene derivative electron transport layer materials, phosphine oxide derivative electron transport layer materials, aromatic ketone derivative electron transport layer materials, lactam derivative electron transport layer materials, and borane derivative electron transport layer materials. Preferably, the first electron transport layer and the second electron transport layer materials can be selected from any one or more of the above-mentioned compounds 12 to 14, and any one or more of the above-mentioned compound 15 and lithium fluoride LiF are doped therein, and the doping ratio is (4 to 6): (6 to 4).

[0107] In an optional embodiment, the electron injection layer can be formed by vacuum evaporation, and the electron injection layer includes any one or more of an alkali metal electron injection layer material or a metal electron injection layer material. For example, the material of the electron injection layer can be LiF, Yb, Mg, Ca, and compounds thereof. Preferably, the material of the electron injection layer can be any one or more of LiF, Yb, and the above-mentioned compound 15.

[0108] In an optional embodiment, the material of the p-type charge generation layer can be selected from any one or more of the following compounds 16 and 17, and any one or more of the above-mentioned compounds 1 and 2 can be doped therein, with a doping ratio of 1% to 5%.

[0109] In an optional embodiment, the material of the n-type charge generation layer can be selected from any one or more of the following compounds 18 and 19, and any one or more of Li, Rb, Cs, Mg, MoO3, WO3, and V2O5 are doped therein, with a doping ratio of 0.5% to 2%.

[0110] In an optional embodiment, the thickness of the electron injection layer is in the range of 0.5nm to 3nm; the thickness of the first electron transport layer and the second electron transport layer is in the range of 20nm to 35nm; the thickness of the first electron blocking layer and the second electron blocking layer is in the range of 5nm to 80nm; the thickness of the first light-emitting layer and the second light-emitting layer is in the range of 30nm to 50nm; the thickness of the first hole blocking layer and the second hole blocking layer is in the range of 5nm to 10nm; the thickness of the first hole transport layer and the second hole transport layer is in the range of 80nm to 130nm; the thickness of the hole injection layer is in the range of 5nm to 30nm; the thickness of the p-type charge generation layer is in the range of 8nm to 10nm; the thickness of the n-type charge generation layer is in the range of 17nm to 19nm. It should be noted that when the thicknesses of the electron injection layer, the first electron transport layer, the second electron transport layer, the first electron blocking layer, the second electron blocking layer, the first light-emitting layer, the second light-emitting layer, the first hole blocking layer, the second hole blocking layer, the first hole transport layer, the second hole transport layer and the hole injection layer in the electroluminescent device are within the above ranges, the colors of the light emitted by the electroluminescent device vary within the same color system.

[0111] In an optional embodiment, the electroluminescent device is prepared by evaporation. For example, at 5*10 -6 Under the vacuum degree of torr, the material is evaporated on a surface with a resistance of 25Ω square by vacuum evaporation. -1 It should be noted that the above example is an optional method proposed to enable those skilled in the art to better understand the solution of the present disclosure. The specific method for preparing the electroluminescent device can be determined according to actual conditions and is not limited by the present disclosure.

[0112] In order to enable those skilled in the art to better understand the performance of the electroluminescent device of the stacked structure provided by the embodiments of the present disclosure, the performance of the electroluminescent device of the stacked structure of some exemplary embodiments is tested and compared. Among them, for the embodiments (Example 4, Example 5, Example 6) and Comparative Example 2, except for the guest luminescent material of the first light-emitting layer and / or the second light-emitting layer, the other layer materials are any one or more of the corresponding optional materials in each layer structure described above.

[0113] The guest luminescent materials of the first luminescent layer and / or the second luminescent layer in the electroluminescent devices of Examples 5 and 6 are respectively the I-1 complex, I-27 complex, and I-46 complex among the above-mentioned heteroleptic phosphorescent iridium complexes. The guest luminescent material of the luminescent layer in the electroluminescent device of Comparative Example 2 is the following compound:

[0114] Table 2 shows a comparison of the performance data of the electroluminescent device embodiment and the comparative example of the stacked structure, as shown in Table 2:

[0115] Table 2 Comparison of performance data of the electroluminescent device embodiment and the comparative example of the stacked structure

[0116] As can be seen from the data in Table 2, the electroluminescent device with a stacked structure using the heteroleptic phosphorescent iridium complex provided by the embodiment of the present disclosure as the guest luminescent material of the luminescent layer has a significantly improved current efficiency compared to the electroluminescent device of Comparative Example 2. Specifically, the current efficiency of Examples 4, 5, and 6 reaches 58 cd / A or more, while the current efficiency of Comparative Example 2 is only 57.25 cd / A. Therefore, the electroluminescent device with a stacked structure using the heteroleptic phosphorescent iridium complex provided by the embodiment of the present disclosure as the guest luminescent material of the luminescent layer can effectively suppress efficiency roll-off. In addition, the electroluminescent device with the heteroleptic phosphorescent iridium complex provided by the embodiment of the present disclosure as the guest luminescent material of the luminescent layer has a narrow full width at half maximum (FWHM), which can obtain phosphorescence with good color purity.

[0117] Based on the same inventive concept, an embodiment of the present disclosure provides a display device, which includes the electroluminescent device as described in the embodiment of the present disclosure.

[0118] The display device further includes: a pixel definition layer, the electroluminescent device is arranged between the pixel definition layers; an encapsulation layer, the encapsulation layer is arranged on the side of the electroluminescent device away from the pixel definition layer, and the material of the encapsulation layer can be any one or more of silicon nitride, acrylic ester / silicon oxynitride and other materials.

[0119] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0120] References herein to "one embodiment," "an embodiment," or "one or more embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Furthermore, please note that instances of the phrase "in one embodiment" do not necessarily all refer to the same embodiment.

[0121] In the description provided herein, numerous specific details are described. However, it is understood that embodiments of the present disclosure may be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0122] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in the claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present disclosure may be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third etc. does not indicate any order. These words may be interpreted as names.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present disclosure.

Claims

1. A phosphorescent material, characterized in that: include: A heteroleptic phosphorescent iridium complex, wherein the heteroleptic phosphorescent iridium complex has the structural formula shown in the following general formula I: Wherein, X1 is O or S, and X2 and X3 are each independently selected from N or C; R1, R2, R3, R4, R5 and R6 are each independently selected from hydrogen, deuterium, halogen, cyano, nitro, hydroxyl, amino, sulfonic acid, sulfonyl, phosphoryl, substituted or unsubstituted C1-C60 alkyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C1-C60 alkoxy, substituted or unsubstituted C1-C60 alkylamino, substituted or unsubstituted C2-C60 alkenyl, substituted or unsubstituted C2-C60 alkynyl, substituted or unsubstituted C5-C60 heterocyclyl, substituted or unsubstituted C10-C60 fused ring or substituted or unsubstituted C5-C60 spirocyclyl.

2. The phosphorescent material according to claim 1, characterized in that The exciton lifetime of the heteroligand phosphorescent iridium complex is less than or equal to 1 μs.

3. The phosphorescent material according to claim 1, characterized in that: The ratio of the current efficiency of the electroluminescent device at a peak brightness of 16000 nits to the current efficiency at a peak brightness of 1300 nits is less than or equal to 0.8, and the electroluminescent device includes a light-emitting layer, and the material of the light-emitting layer includes the heteroligand phosphorescent iridium complex.

4. The phosphorescent material according to claim 1, characterized in that: The substitution sites of R1, R2 and R3 are at any position of their rings; R1 and R3 represent a monosubstituent, a disubstituent, a trisubstituent or no substituent; R2 and R5 represent a monosubstituent, a disubstituent or no substituent; and R4 and R6 represent a monosubstituent or no substituent.

5. The phosphorescent material according to claim 1, characterized in that: Any adjacent R1, R2, and R3 substituents form a condensed ring or an aromatic heterocycle with the ring in which they are located, and the R1, R2, and R3 that do not form a condensed ring or an aromatic heterocycle are each independently selected from any one of hydrogen, deuterium, a substituted or unsubstituted C1-C60 alkyl group, a substituted or unsubstituted C6-C60 aryl group, a substituted or unsubstituted C3-C60 cycloalkyl group, a substituted or unsubstituted C5-C60 heterocyclic group, a substituted or unsubstituted C10-C60 condensed ring group, and a substituted or unsubstituted C5-C60 spirocyclic group.

6. The phosphorescent material according to claim 1, characterized in that: R1, R2, R3, R4, R5 and R6 are each independently selected from any one of hydrogen, deuterium, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C5-C30 heterocyclic group, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C10-C30 condensed ring group.

7. The phosphorescent material according to claim 1, characterized in that: R1 is any one of tert-butyl, methyl and hydrogen, R2 is any one of methyl, hydrogen and deuterium, R3 is any one of hydrogen, methyl and tert-butyl, R4 is any one of hexyl, methyl and isopropyl, R5 is hydrogen, and R6 is any one of hexyl, methyl and isopropyl.

8. The phosphorescent material according to claim 1, characterized in that: The heteroligand phosphorescent iridium complex is selected from any one of the following complexes:

9. An electroluminescent device, characterized in that: The electroluminescent device comprises: an anode, a cathode and at least one light-emitting layer, wherein the light-emitting layer is arranged between the anode and the cathode, and the light-emitting layer comprises the phosphorescent material according to any one of claims 1 to 8; The light-emitting layer includes a host light-emitting material and a guest light-emitting material, and the phosphorescent material is at least one of the host light-emitting material and the guest light-emitting material.

10. The electroluminescent device according to claim 9, characterized in that The electroluminescent device comprises: A hole injection layer, a hole transport layer and an electron blocking layer, wherein the hole injection layer, the hole transport layer and the electron blocking layer The transport layer and the electron blocking layer are sequentially arranged between the anode and the light-emitting layer along a first direction, wherein the first direction is the direction from the anode to the cathode; A hole blocking layer, an electron transport layer, and an electron injection layer, wherein the hole blocking layer, the electron transport layer, and the electron injection layer are sequentially arranged between the light emitting layer and the cathode along the first direction.

11. The electroluminescent device according to claim 9, characterized in that The thickness of the electron injection layer is in the range of 0.5 nm to 3 nm; The thickness of the electron transport layer is in the range of 20 nm to 35 nm; The thickness of the electron blocking layer is in the range of 5 nm to 80 nm; The thickness of the light-emitting layer is in the range of 30nm to 50nm; The thickness of the hole blocking layer is in the range of 5 nm to 10 nm; The thickness of the hole transport layer is in the range of 80nm to 130nm; The thickness of the hole injection layer is in the range of 5 nm to 30 nm.

12. The electroluminescent device according to claim 9, characterized in that The light-emitting layer comprises: A first light-emitting layer and a second light-emitting layer, wherein a material of at least one of the first light-emitting layer and the second light-emitting layer is the phosphorescent material according to any one of claims 1 to 8.

13. The electroluminescent device according to claim 12, characterized in that The electroluminescent device comprises: A charge generation layer, the charge generation layer is disposed between the first light-emitting layer and the second light-emitting layer, the charge generation layer includes a p-type charge generation layer and an n-type charge generation layer; A hole injection layer, a first hole transport layer and a first electron blocking layer, wherein the hole injection layer, the first hole transport layer and the first electron blocking layer are sequentially arranged between the anode and the first light-emitting layer along a first direction, and the first direction is a direction from the anode to the cathode; A second hole blocking layer, a second electron transport layer and an electron injection layer, wherein the second hole blocking layer, the second electron transport layer and the electron injection layer are sequentially arranged between the cathode and the second light-emitting layer along the first direction; a first hole blocking layer, the first hole blocking layer being disposed between the first light emitting layer and the n-type charge generating layer; A second hole transport layer and a second electron blocking layer, wherein the second hole transport layer and the second electron blocking layer are sequentially arranged between the p-type charge generation layer and the second light emitting layer along the first direction.

14. The electroluminescent device according to claim 13, characterized in that The electroluminescent device further comprises a first electron transport layer, wherein the first electron transport layer is disposed between the n-type charge generation layer and the first hole blocking layer; The thickness of the electron injection layer is in the range of 0.5 nm to 3 nm; The thickness of the first electron transport layer and the second electron transport layer is in the range of 20 nm to 35 nm; The thickness of the first electron blocking layer and the second electron blocking layer is in the range of 5 nm to 80 nm; The thickness of the first light-emitting layer and the second light-emitting layer is in the range of 30nm to 50nm; The thickness of the first hole blocking layer and the second hole blocking layer is in the range of 5 nm to 10 nm; The thickness of the first hole transport layer and the second hole transport layer is in the range of 80nm to 130nm; The thickness of the hole injection layer is in the range of 5 nm to 30 nm; The thickness of the p-type charge generation layer is in the range of 8 nm to 10 nm; The thickness of the n-type charge generation layer is in the range of 17 nm to 19 nm.

15. A display device, characterized in that: Comprising the electroluminescent device according to any one of claims 9 to 14.

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