Organic light-emitting device and application thereof

Abstract

The invention provides an organic light-emitting device and application thereof, the organic light-emitting device comprises an anode, a cathode and a light-emitting layer, a hole transport region is arranged between the light-emitting layer and the anode, the hole transport region comprises m organic functional layers, and m is greater than or equal to 2; the hole mobility of each organic functional layer is greater than or equal to 1.0 * 10 <-4 > cm < 2 > V <-1 > s <-1 >; the hole mobility of the xth organic functional layer and the hole mobility of the (x + 1) th organic functional layer are mu x and mu x + 1 respectively, and mu x / mu x + 1 is larger than 1 and smaller than or equal to 2; the HOMO energy level of the mth organic functional layer is HOMOm, and the HOMO energy level of the first host material containing the electron donating group is HOMOPH; hOMOm-HOMOPH is greater than or equal to 0 and less than or equal to 0.40 Through the design and matching of the hole mobility and the HOMO energy level of the hole transport region, the device has high luminous efficiency, low driving voltage, long service life and low capacitance value, and the problem of'smear 'of a screen is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic electroluminescence, and in particular relates to an organic electroluminescent device and applications thereof. Background Art

[0002] Organic light-emitting diodes (OLEDs) typically have a sandwich-like structure, consisting of anode and cathode electrodes and a layer of organic functional materials sandwiched between them. The core of an OLED device is a thin film structure containing a variety of organic functional materials. Common organic functional materials include hole injection materials, hole transport materials, electron blocking materials, electron injection materials, electron transport materials, hole blocking materials, luminescent host materials, and luminescent guest materials (i.e., dopants, dyes). When the OLED device is powered on, electrons and holes are injected and transported to the light-emitting region, where they recombine, generating excitons and emitting light.

[0003] To further meet the ever-increasing demand for improved optoelectronic performance in OLED devices, as well as the energy-saving needs of mobile electronic devices, it is necessary to continuously develop OLED materials with even better performance. In recent years, researchers have conducted numerous attempts and explorations to improve device efficiency and stability, with the search for new materials being the most common approach to enhance device performance. Consequently, a large number of novel organic functional materials have been developed for use in OLED devices. While these materials have shown some improvement in device performance, the potential for improvement is limited due to the replacement of new materials, and the inability to effectively combine materials hinders improvements in device performance.

[0004] In addition, the researchers also discovered new technical problems in the terminal use of the material. For example, during the use of the display panel, the light point does not completely extinguish after the power is cut off, but instead emits a short, weak light. This causes the screen to have residual images of the previous animation during the video display process. This phenomenon is called "smear (afterimage)", which brings inconvenience to the user's visual experience. The researchers conducted an in-depth analysis of the "smear" problem and found that when a single device emits a faint light, its external power supply is zero, so the power supply factor can be ruled out as having an impact on the occurrence of this problem. In order to better improve device performance and solve the "smear" problem, and to deeply understand the device structure, the researchers analyzed the cause of its light emission: inside the device, due to the existence of energy levels between the various organic layers and the influence of the material's transmission characteristics, excess charges accumulate at the film interface; after losing the external field strength constraint, the excess charges move and recombine in the light-emitting layer to emit secondary light; this light point is equivalent to the discharge process of an organic capacitor element, which ultimately leads to secondary light emission, causing the screen "smear" problem during the display process.

[0005] Analysis of screen "smearing" found that the essence of this phenomenon is equivalent to the discharge process of an organic flat-plate capacitor, and the size of the capacitor determines the strength and duration of its secondary luminescence. According to the definition of capacitance, the ratio of the charge Q carried by the capacitor to the voltage U between the two poles of the capacitor is the capacitance of the capacitor; capacitance is the ratio of charge to voltage, usually represented by the symbol C, and the formula is: C = Q / V; Q represents the amount of stored charge, and V represents the voltage on the capacitor. According to the definition formula of capacitance, it can be seen that the size of the capacitor is related to the amount of charge and voltage. In order to ensure the normal brightness of the light-emitting device, its voltage is a fixed value and cannot be changed. Therefore, the only way to achieve the purpose of reducing capacitance and weakening or avoiding luminescence is to reduce the number of charges stored inside the device. However, no effective method has been proposed to effectively reduce capacitance and avoid smearing.

[0006] Therefore, providing an organic electroluminescent device with high luminous efficiency, long life, low voltage and low capacitance is an urgent problem to be solved in this field. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an organic electroluminescent device and its application. By designing and matching the hole mobility and energy level of the hole transport zone, the accumulation of holes at the interface is significantly reduced, thereby effectively reducing the capacitance value of the organic electroluminescent device, and ensuring that the device has lower voltage, higher luminous efficiency and longer service life, thereby improving the overall performance.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides an organic electroluminescent device, comprising an anode, a cathode, and a light-emitting layer disposed between the anode and the cathode, wherein a hole transport region is disposed between the light-emitting layer and the anode, and the hole transport region comprises m organic functional layers, where m is selected from an integer ≥ 2;

[0010] The hole mobility of each organic functional layer in the hole transport region is independently ≥1.0×10 -4 cm 2 V - 1 s -1 The direction from the anode to the cathode is the first direction, and the organic functional layers are numbered in sequence according to the first direction. The hole mobility of the x-th organic functional layer is μ x , the hole mobility of the x+1th organic functional layer is μ x+1 , 1<μ x / μ x+1 ≤2; where x is an integer from 1 to m-1;

[0011] The HOMO energy level of the mth organic functional layer is HOMO m The light-emitting layer includes a first host material containing an electron-donating group, and the HOMO energy level of the first host material is HOMO PH ; 0≤HOMO m -HOMO PH ≤0.40eV.

[0012] After in-depth research, the present invention designs the hole transport region as follows: (1) The hole mobility of each organic functional layer is independently ≥1.0×10 -4 cm 2 V -1 s -1 , maintain a high value, ensure that the hole transport region has excellent hole migration and transport capabilities, ensure that the device has a low voltage, and maintain a high level of luminous efficiency and life; (2) with the direction from the anode to the cathode as the first direction, along the first direction, the hole mobility of each organic functional layer in the hole transport region gradually decreases (μ x / μ x+1 >1), and the difference between adjacent organic functional layers is small (μ x / μ x+1 ≤2), thereby controlling the number of holes generated at the hierarchical interface to a certain extent and reducing the number of holes at the interface; (3) the HOMO energy level difference between the organic functional layer adjacent to the light-emitting layer in the hole transport region, that is, the mth organic functional layer (also known as the "electron blocking layer", EBL) and the first host material in the light-emitting layer (EML) is small, controlling 0≤HOMO m -HOMO PH ≤0.40eV, which can reduce the hole injection barrier and reduce the holes accumulated on this interface. The present invention is based on the design of the aforementioned hole mobility and energy level, and the mutual matching of the hole mobility and energy level between the layers, which greatly reduces the accumulation of holes at the interface, especially reduces the hole accumulation at the EBL / EML interface, so as to reduce the capacitance value of the device; at the same time, the mobility and HOMO energy level of each organic functional layer in the hole transport region match each other and are well matched with the light-emitting layer, thereby improving the balance of holes and electrons in the light-emitting layer and enhancing energy utilization efficiency, thereby effectively improving the luminous efficiency and life of the organic electroluminescent device, reducing the voltage, and at the same time reducing the accumulation of the number of excess holes, reducing the energy stored in the capacitor of the device, reducing the capacitance value of the device, reducing or avoiding the problem of screen drag (afterimage) in the panel display process of the organic light-emitting device, and improving the yield.

[0013] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0014] In the present invention, the hole transport region includes m organic functional layers, where m ≥ 2, and may be, for example, 2, 3, 4, 5, 6, etc. The organic functional layers in the hole transport region are numbered in ascending order along the first direction (the direction from the anode to the cathode), i.e., the organic functional layer closest to the anode in the hole transport region is the first organic functional layer, and the organic functional layer closest to the light-emitting layer is the mth organic functional layer; the mth organic functional layer is adjacent to the light-emitting layer and is therefore named an "electron blocking layer" (EBL); the first to m-1th organic functional layers are collectively referred to as "hole transport layers" (HTL). The number of HTLs in the organic electroluminescent device is m-1, i.e., may be 1, 2, 3, 4, 5, etc.

[0015] Under the same test conditions, the hole mobility of each organic functional layer in the hole transport region is independently ≥1.0×10 -4 cm 2 V -1 s -1 , for example, it can be 1.1×10 -4 cm 2 V -1 s -1 , 1.2×10 -4 cm 2 V -1 s -1 , 1.5×10 -4 cm 2 V -1 s -1 , 1.8×10 -4 cm 2 V -1 s -1 , 2×10 -4 cm 2 V -1 s -1 , 2.2×10 -4 cm 2 V -1 s -1 , 2.5×10 -4 cm 2 V -1 s -1 , 2.8×10 -4 cm 2 V -1 s -1 , 3×10 -4 cm 2 V -1 s -1 , 3.2×10 -4 cm 2V -1 s -1 , 3.5×10 -4 cm 2 V -1 s -1 , 3.8×10 -4 cm 2 V -1 s -1 , 4×10 -4 cm 2 V -1 s -1 , 4.2×10 -4 cm 2 V -1 s -1 , 4.5×10 -4 cm 2 V -1 s -1 , 4.8×10 -4 cm 2 V -1 s -1 or 5×10 -4 cm 2 V -1 s -1 wait.

[0016] The hole mobility of two adjacent organic functional layers in the hole transport region satisfies the following relationship: 1<μ x / μ x+1 ≤2, μ x / μ x+1 It can be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8 or 1.9, etc.

[0017] HOMO of EBL m and the HOMO of the first host material in the light-emitting layer PH Satisfies the following relationship: 0≤HOMO m -HOMO PH ≤0.40eV, HOMO m ≥HOMO PH The difference between the two can be 0, 0.02eV, 0.05eV, 0.08eV, 0.10eV, 0.12eV, 0.15eV, 0.18eV, 0.20eV, 0.22eV, 0.25eV, 0.28eV, 0.30eV, 0.32eV, 0.35eV, 0.38eV, etc.

[0018] Preferably, 0≤HOMO m -HOMO PH ≤0.30eV.

[0019] Preferably, the HOMO energy level of the x-th organic functional layer is HOMO x , the HOMO energy level of the x+1th organic functional layer is HOMO x+1 , -0.05eV≤HOMO x -HOMO x+1 ≤0.15eV, HOMO x -HOMO x+1 It may be -0.04 eV, -0.02 eV, 0, 0.02 eV, 0.05 eV, 0.08 eV, 0.10 eV, 0.12 eV, or 0.14 eV.

[0020] More preferably, 0≤HOMO x -HOMO x+1 ≤0.10eV.

[0021] As a preferred technical solution of the present invention, the HOMO energy level difference between the two adjacent organic functional layers in the hole transport region is small, which can further avoid the generation of excessive charges at the interface, reduce the accumulation of holes at the interface, and make the organic electroluminescent device have a lower capacitance value, reduce the possibility of smearing, and improve product yield.

[0022] Preferably, the energy gap of the material of the mth organic functional layer (electron blocking layer EBL) is ≤3.2 eV, for example, it may be 2.5 eV, 2.6 eV, 2.7 eV, 2.8 eV, 2.9 eV, 3 eV, 3.1 eV or 3.15 eV.

[0023] In the present invention, the term "energy gap" can be expressed as E g , through formula E g =1240 / UV-vis on-set Calculated, where UV-vis on-set It is obtained by UV-visible spectrophotometry, which is the wavelength corresponding to the peak of the absorption spectrum.

[0024] Preferably, the materials of the first organic functional layer to the m-1th organic functional layer (ie, the hole transport layer) in the hole transport region each independently have a structure as shown in Formula I:

[0025]

[0026] In Formula I, Y1 and Y2 are each independently selected from any one of a single bond, O, S, CR1R2 or NR3, and at most one of Y1 and Y2 is a single bond. When one of Y1 and Y2 is a single bond, the fused ring structure can be understood as a structure in which a five-membered ring (e.g., a pyrrole ring, a furan ring, a thiophene ring, or a cyclopentadiene ring) is fused to two benzene rings; when neither Y1 nor Y2 is a single bond, the fused ring structure can be understood as a structure in which three six-membered rings are fused.

[0027] R1, R2, and R3 are each independently selected from any one of hydrogen, substituted or unsubstituted C1-C20 straight or branched alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl; R1 and R2 are not connected or are connected to form a ring by a chemical bond.

[0028] In Formula I, L 11 , L 12 are each independently selected from any one of a single bond, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C3-C30 heteroarylene group; when L 11 When it is a single bond, it represents Ar 11 Directly connected to the N atom through a single bond; when L 12 When it is a single bond, it represents Ar 12 It is directly connected to the N atom via a single bond.

[0029] In Formula I, Ar 11 、Ar 12 Each is independently selected from any one of a substituted or unsubstituted C6-C30 aryl group and a substituted or unsubstituted C3-C30 heteroaryl group.

[0030] R1, R2, R3, L 11 , L 12 、Ar 11 、Ar 12 The substituents substituted therein are each independently selected from any one of halogen, cyano, nitro, hydroxyl, amino, carboxyl, thiol, C1-C20 straight or branched alkyl, C2-C20 alkenyl, C3-C20 cycloalkyl, C2-C20 heterocycloalkyl, C6-C30 aryl, C3-C30 heteroaryl, C6-C30 aryloxy, C3-C30 heteroaryloxy, C6-C30 arylamino, and C3-C30 heteroarylamino, or a combination of at least two thereof.

[0031] In the present invention, the "substituted or unsubstituted" group may be substituted with one or more substituents. When there are multiple substituents (at least two), they may be the same or different. The same expressions used below have the same meaning. Unless otherwise specified, the range of substituents used in the present invention is as shown above and will not be repeated here.

[0032] In the present invention, the expression of chemical elements, unless otherwise specified, includes the concept of isotopes with the same chemical properties. For example, hydrogen (H) includes 1 H (hydrogen), 2 H (deuterium, D), 3 H (tritium, T), etc.; carbon (C) includes 12 C. 13 C, etc.

[0033] In the present invention, unless otherwise specified, the heteroatom of the heteroaryl group is selected from N, O, S, P, B, Si or Se, preferably N, O or S.

[0034] In the present invention, the expression of a ring structure crossed by “-” indicates that the connection site is any position on the ring structure that can form a bond.

[0035] In the present invention, dotted lines, "-*", "*", "-#", and "#" all represent the attachment sites of groups.

[0036] In the present invention, the expression Ca-Cb represents that the number of carbon atoms in the group is ab. Unless otherwise specified, the number of carbon atoms does not include the number of carbon atoms in the substituent.

[0037] In the present invention, “each independently” means that when there are multiple subjects, they may be the same or different.

[0038] In the present invention, the C1-C20 can all be C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C12, C14, C15, C16, C18, etc.

[0039] The C3-C20 can all be C3, C4, C5, C6, C7, C8, C9, C10, C12, C14, C15, C16, C18, etc.

[0040] The C2-C20 can all be C2, C3, C4, C5, C6, C7, C8, C9, C10, C12, C14, C15, C16, C18, etc.

[0041] The C6-C30 can all be C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, etc.

[0042] The C3-C30 can all be C3, C4, C5, C6, C7, C8, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, etc.

[0043] The C6-C20 can all be C6, C9, C10, C12, C14, C16, C18, etc.

[0044] The C3-C20 can all be C3, C4, C5, C6, C7, C8, C9, C10, C12, C14, C16, C18, etc.

[0045] The C6-C40 can all be C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, C30, C32, C34, C36, C38, etc.

[0046] The C3-C40 can all be C3, C4, C5, C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, C30, C32, C34, C36, C38, etc.

[0047] In the present invention, the C6-C30 aryl group, more preferably the C6-C26 aryl group, includes a monocyclic aryl group and a condensed ring aryl group; the monocyclic aryl group means that the group contains at least one phenyl group, and when it contains at least two phenyl groups, the phenyl groups are connected by a single bond, and illustratively include but are not limited to: phenyl, biphenyl, terphenyl, quaterphenyl, etc.; the condensed ring aryl group means that the group contains at least two aromatic rings, and the aromatic rings share two adjacent carbon atoms. The groups fused to each other include, but are not limited to, naphthyl, anthracenyl, phenanthrenyl, indenyl, fluorenyl and its 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, spirobifluorenyl, benzofluorenyl, etc.), fluoranthenyl, triphenylene, pyrenyl, perylene, It should be noted that monocyclic aromatic groups and condensed aromatic groups connected by a single bond also fall within the scope of aromatic groups, such as phenylnaphthyl, naphthylphenyl, naphthylnaphthyl, phenylnaphthylphenyl, phenanthrenyl, naphthylanthryl, etc.

[0048] The C3-C30 heteroaryl group, further preferably a C3-C20 heteroaryl group, includes a monocyclic heteroaryl group or a condensed-ring heteroaryl group. The monocyclic heteroaryl group means that the molecule contains at least one heteroaryl group. When the molecule contains a heteroaryl group and other groups (such as aryl, heteroaryl, etc.), the heteroaryl group and the other group are connected by a single bond, and illustratively include but are not limited to: pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, furyl, thienyl, pyrrolyl, bipyridyl, phenylpyridyl, pyridylphenyl, etc. The fused-ring heteroaryl group refers to a group containing at least one aromatic heterocycle and one aromatic ring (aromatic heterocycle or aromatic ring) in the molecule, and the two share two adjacent atoms fused to each other, including but not limited to: quinolyl, isoquinolyl, quinoxalinyl, quinazolinyl, benzofuranyl, benzothiophenyl, isobenzofuranyl, isobenzothiophenyl, indolyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl and its derivatives (N-phenylcarbazolyl, N-naphthylcarbazolyl, benzocarbazolyl, dibenzocarbazolyl, indolecarbazolyl, azacarbazolyl, etc.), acridinyl, phenothiazinyl, phenoxazinyl, hydroacridinyl, etc. It should be noted that heteroaryl groups and heteroaryl groups connected by a single bond, and aryl groups and heteroaryl groups connected by a single bond also fall within the scope of heteroaryl groups, for example, phenyldibenzofuranyl, dibenzofuranylphenyl, phenyldibenzothienyl, dibenzothienylphenyl, etc.

[0049] In the present invention, the C6-C30 aryloxy group is a monovalent group formed by connecting the above-mentioned aryl groups with O, and the C3-C30 heteroaryloxy group is a monovalent group formed by connecting the above-mentioned heteroaryl groups with O.

[0050] In the present invention, specific examples of the C6-C40 arylamino group and the C6-C30 arylamino group are monovalent groups in which at least one hydrogen in -NH2 is replaced by the above-mentioned aryl group, including but not limited to phenylamino, methylphenylamino, naphthylamino, anthrylamino, phenanthrenylamino, biphenylamino, dimethylfluorenylamino, etc. Specific examples of the C3-C40 heteroarylamino group and the C3-C30 heteroarylamino group are monovalent groups in which at least one hydrogen in -NH2 is replaced by the above-mentioned heteroaryl group, including but not limited to dibenzofuranylamino, dibenzothienylamino, etc.

[0051] In the present invention, specific examples of the C6-C40 arylsilyl group are monovalent groups in which at least one hydrogen in -SiH3 is replaced by the above-mentioned aryl group, including but not limited to triphenylsilyl, biphenylsilyl, naphthylsilyl, anthracenylsilyl, phenanthrenylsilyl, etc. Specific examples of the C3-C40 heteroarylsilyl group are monovalent groups in which at least one hydrogen in -SiH3 is replaced by the above-mentioned heteroaryl group, including but not limited to dibenzofuranylsilyl, dibenzothienylsilyl, dibenzothienyldi(phenyl)silyl, dibenzofuranyldi(phenyl)silyl, etc.

[0052] The C1-C20 straight chain or branched chain alkyl group, preferably a C1-C10 straight chain or branched chain alkyl group, illustratively includes but is not limited to: 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.

[0053] Specific examples of the C1-C20 alkoxy group include monovalent groups obtained by connecting the above-mentioned linear or branched alkyl groups to O.

[0054] A specific example of the C1-C20 alkylsilyl group is a monovalent group in which at least one hydrogen in -SiH3 is replaced by the above-mentioned straight-chain or branched alkyl group; a specific example of the C1-C20 alkylamino group is a monovalent group in which at least one hydrogen in -NH2 is replaced by the above-mentioned straight-chain or branched alkyl group.

[0055] The C3-C20 cycloalkyl group, preferably a C1-C10 cycloalkyl group, includes a monocyclic alkyl group or a polycyclic alkyl group. A monocyclic alkyl group refers to an alkyl group containing a single cyclic structure, and a polycyclic alkyl group refers to a structure composed of two or more cycloalkyl groups sharing one or more ring carbon atoms. Examples thereof include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and adamantyl groups.

[0056] Specific examples of the C2-C20 heterocycloalkyl group include monovalent groups formed by replacing one of the ring carbon atoms in the above cycloalkyl group with a heteroatom, wherein the heteroatom is preferably N, O or S.

[0057] The C2-C20 alkenyl group, preferably a C2-C10 alkenyl group, contains at least one C=C, and illustratively includes but is not limited to: vinyl, propenyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, butadienyl, pentadienyl, etc.

[0058] Preferably, Y1 is selected from any one of O, S or CR1R2; and / or, Y2 is selected from any one of a single bond, O, S or CR1R2.

[0059] Preferably, R1 and R2 are each independently selected from any one of a substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) linear or branched alkyl group, a substituted or unsubstituted C2-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) alkenyl group, or a substituted or unsubstituted C6-C20 (e.g., C6, C7, C8, C9, C10, C12, C14, C16, or C18, etc.) aryl group, further preferably any one of a C1-C6 linear or branched alkyl group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a phenylnaphthyl group, or a naphthylphenyl group, and more preferably a methyl group, a phenyl group, or a biphenyl group.

[0060] Preferably, in Formula I Any one selected from the following groups:

[0061] Preferably, the L 11 , L 12 Each is independently selected from a single bond, a substituted or unsubstituted group: Dashed lines represent the attachment sites of the groups;

[0062] Y3 is selected from O, S, CR 11 R 12 or NR 13 Any one of .

[0063] R 11 、R 12 、R 13 Each is independently selected from any one of hydrogen, C1-C20 straight or branched alkyl, C2-C20 alkenyl, C6-C30 aryl or C3-C30 heteroaryl; the R 11 and R 12 They are not connected or connected to form a ring through chemical bonds.

[0064] Preferably, the R 11 、R 12 、R 13 Each is independently selected from any one of hydrogen, C1-C10 (for example, C2, C3, C4, C5, C6, C7, C8, C9, etc.) straight chain or branched alkyl, C2-C10 (for example, C3, C4, C5, C6, C7, C8, C9, etc.) alkenyl, C6-C20 (for example, C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) aryl, further preferably any one of C1-C6 straight chain or branched alkyl, phenyl, biphenyl, terphenyl, naphthyl, phenylnaphthyl or naphthylphenyl, more preferably methyl, phenyl or biphenyl.

[0065] Preferably, the L 11 Selected from

[0066] More preferably, the L 11 Selected from Among them, -* represents the connection site between the group and N, -# represents the connection site between the group and Ar 11 The attachment site;

[0067] Preferably, the L 12 Selected from single bonds, Dashed lines represent the sites of attachment of the groups.

[0068] Preferably, the Ar 11 、Ar 12 Each is independently selected from any one of the following substituted or unsubstituted groups:

[0069] Dashed lines represent the sites of attachment of the groups.

[0070] Preferably, the materials of the first to m-1th organic functional layers (hole transport layers HTL) in the hole transport zone are each independently selected from any one or a combination of at least two of the following compounds H1-H40:

[0071]

[0072] Preferably, the material of the mth organic functional layer (electron blocking layer EBL) has a structure as shown in Formula II:

[0073]

[0074] In formula II, L2 is selected from any one of a single bond, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C3-C30 heteroarylene group; when L2 is a single bond, it represents Ar 23 It is directly connected to the N atom via a single bond.

[0075] In formula II, Ar 21 、Ar 22 、Ar 23 Each is independently selected from any one of a substituted or unsubstituted C6-C30 aryl group and a substituted or unsubstituted C3-C30 heteroaryl group.

[0076] In Formula II, R 21Any one selected from substituted or unsubstituted C1-C20 straight or branched alkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl; adjacent R 21 are not connected or connected to form a ring through chemical bonds, the R 21 It is not connected to adjacent ring structures or is connected to form a ring through chemical bonds.

[0077] In the present invention, "R 21 "Not connected to the adjacent ring structure" means that R 21 Only connected to C atoms by single bonds; "R 21 "Connected to adjacent ring structures by chemical bonds to form a ring" means R 21 In addition to being connected to the C atom by chemical bonds, it is also connected to adjacent rings (such as the benzene ring shown in Formula II, Ar 21 The rings in the rings are connected by chemical bonds to form a fused ring structure. When the same descriptions are mentioned below, they all have the same meanings and will not be repeated one by one.

[0078] “Adjacent R 21 When the two adjacent R 21 Together they form a fused ring structure.

[0079] L2、Ar 21 、Ar 22 、Ar 23 、R 21 The substituents substituted in the above-mentioned group are each independently selected from any one or a combination of at least two of halogen, cyano, nitro, hydroxyl, amino, carboxyl, C1-C20 straight or branched alkyl, C2-C20 alkenyl, C1-C20 alkoxy, C1-C20 alkylsilyl, C1-C20 alkylamino, C3-C20 cycloalkyl, C2-C20 heterocycloalkyl, C6-C30 aryl, C3-C30 heteroaryl, C6-C30 aryloxy, C3-C30 heteroaryloxy, C6-C30 arylamino, and C3-C30 heteroarylamino;

[0080] In formula II, n represents a substituent R 21 The number is selected from an integer of 0-4, for example, it can be 0, 1, 2, 3 or 4; preferably 1 or 2.

[0081] Preferably, the material of the mth organic functional layer has a structure as shown in Formula IIA or Formula IIB:

[0082]

[0083] Among them, L2, Ar 21 、Ar 22、Ar 23 Having the same defined range as in Formula II;

[0084] R 22 、R 23 are each independently selected from any one of hydrogen, substituted or unsubstituted C1-C20 straight or branched alkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl; the R 22 、R 23 Each is independently not connected to the adjacent ring structure or connected to form a ring through a chemical bond.

[0085] Preferably, the R 22 、R 23 Each is independently selected from any one of hydrogen, substituted or unsubstituted C6-C20 (such as C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) aryl groups.

[0086] Preferably, the R 22 and R 23 Not hydrogen at the same time.

[0087] More preferably, the R 22 and R 23 One of them is hydrogen, and the other is selected from any one of the following substituted or unsubstituted groups: Dashed lines represent the attachment sites of the groups.

[0088] Preferably, in Formula II, L2 is selected from any one of a single bond, a substituted or unsubstituted C6-C20 (e.g., C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) arylene group.

[0089] Further preferably, L2 is selected from any one of the following groups: Dashed lines represent the sites of attachment of the groups.

[0090] Preferably, the Ar 23 It has the structure shown in formula a:

[0091]

[0092] In formula a, the Ar 23 Connected to L2 through any linkable site; It should be noted that the Ar 23 The “any site that can be connected” includes not only the carbon atom shown in formula a, but also any site on X1 and X2.

[0093] In formula a, X1 and X2 are each independently selected from a single bond, O, S, CR 31 R 32 or NR 33 Any one of , and at most one of X1 and X2 is a single bond. When one of X1 and X2 is a single bond, the fused ring structure can be understood as a structure in which a five-membered ring (e.g., a pyrrole ring, a furan ring, a thiophene ring, or a cyclopentadiene ring) is fused with two benzene rings; when neither X1 nor X2 is a single bond, the fused ring structure can be understood as a structure in which three six-membered rings are fused.

[0094] R 31 、R 32 、R 33 Each is independently selected from any one of hydrogen, C1-C20 straight or branched alkyl, C2-C20 alkenyl, C6-C30 aryl or C3-C30 heteroaryl; the R 31 and R 32 They are not connected or connected to form a ring through chemical bonds.

[0095] Preferably, the R 31 、R 32 、R 33 Each is independently selected from any one of hydrogen, C1-C10 (for example, C2, C3, C4, C5, C6, C7, C8, C9, etc.) straight chain or branched alkyl, C2-C10 (for example, C3, C4, C5, C6, C7, C8, C9, etc.) alkenyl, C6-C20 (for example, C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) aryl, further preferably any one of C1-C6 straight chain or branched alkyl, phenyl, biphenyl, terphenyl, naphthyl, phenylnaphthyl or naphthylphenyl, more preferably methyl, phenyl or biphenyl.

[0096] Preferably, the Ar 23 Selected from

[0097] Dashed lines represent the sites of attachment of the groups.

[0098] Preferably, the Ar 21 、Ar 22 Each is independently selected from any one of the following substituted or unsubstituted groups:

[0099]

[0100] Dashed lines represent the sites of attachment of the groups.

[0101] Preferably, the material of the mth organic functional layer is selected from any one or a combination of at least two of the following compounds E1-E59:

[0102]

[0103]

[0104] In a preferred technical solution of the present invention, the material of the 1st organic functional layer to the m-1th organic functional layer (hole transport layer) in the hole transport zone is H36; the material of the mth organic functional layer (electron blocking layer) is selected from any one of E3, E5, E8, E10, E12, E16, E21, E25, E26, E28, E30, E33, E37, E39, E40, E42, E47, E49, E51, E56, and E58, or a combination of at least two of them.

[0105] In a preferred technical solution of the present invention, the materials of the 1st organic functional layer to the m-1th organic functional layer (hole transport layer) in the hole transport zone are selected from any one of H4, H8, H9, H14, H16, H17, H18, H20, H24, H25, H28, H29, H30, H31, H35, H36, and H40, or a combination of at least two thereof; the material of the mth organic functional layer (electron blocking layer) is selected from E39.

[0106] Preferably, the first host material in the light-emitting layer contains an electron-donating group, which is also called an "electron-donating group" or "electron-rich group", meaning that the group replaces the hydrogen on the benzene ring to increase the electron cloud density on the benzene ring, and its Hammett value is negative. The Hammett value refers to the characterization of the charge affinity of a specific group, which is a measure of an electron-deficient group (positive Hammett value) or an electron-donating group (negative Hammett value). The electron-donating group illustratively includes, but is not limited to, arylamino and its derivatives, carbazolyl and its derivatives, dibenzofuranyl, dibenzothiophenyl, phenothiazinyl, phenoxazinyl, hydroacridinyl, etc.

[0107] Preferably, the first host material has a structure as shown in Formula III:

[0108] R D -L3-Ar3 Formula II;

[0109] In formula III, L3 is selected from any one of a single bond, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C3-C30 heteroarylene group; when L3 is a single bond, it represents the D Connect directly with a single button.

[0110] In formula III, Ar3 is selected from any one of a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C30 heteroaryl group, a substituted or unsubstituted C6-C40 arylamino group, a substituted or unsubstituted C3-C40 heteroarylamino group, a substituted or unsubstituted C6-C40 arylsilyl group, and a substituted or unsubstituted C3-C40 heteroarylsilyl group.

[0111] In formula III, R D Any one selected from the following substituted or unsubstituted groups:

[0112] Dashed lines represent the sites of attachment of the groups.

[0113] R 41 Each is independently selected from any one of a substituted or unsubstituted C1-C20 straight or branched alkyl group, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C3-C30 heteroaryl group, preferably any one of a substituted or unsubstituted C6-C20 (for example, C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) aryl group, and a substituted or unsubstituted C3-C20 (for example, C3, C4, C5, C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) heteroaryl group, and further preferably any one of a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a phenylnaphthyl group, a naphthylphenyl group, a dibenzofuranyl group, and a dibenzothiophenyl group.

[0114] L3, Ar3, R D 、R 41 The substituents substituted therein are each independently selected from any one of halogen, cyano, nitro, hydroxyl, amino, carboxyl, C1-C20 straight or branched alkyl, C2-C20 alkenyl, C1-C20 alkoxy, C1-C20 alkylsilyl, C1-C20 alkylamino, C3-C20 cycloalkyl, C2-C20 heterocycloalkyl, C6-C30 aryl, C3-C30 heteroaryl, C6-C30 aryloxy, C3-C30 heteroaryloxy, C6-C30 arylamino, and C3-C30 heteroarylamino, or a combination of at least two thereof.

[0115] Preferably, L3 is selected from any one of the following groups:

[0116] Preferably, the first host material is a red light host material having a structure shown in Formula III, and R D Any one selected from the following substituted or unsubstituted groups:

[0117] R 41 Preferably, it is any one of a substituted or unsubstituted C6-C20 (e.g., C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) aryl group, or a substituted or unsubstituted C3-C20 (e.g., C3, C4, C5, C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) heteroaryl group, and more preferably any one of a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a phenylnaphthyl group, a naphthylphenyl group, a dibenzofuranyl group, or a dibenzothiophenyl group.

[0118] Preferably, Ar3 is selected from any one of the following substituted or unsubstituted groups:

[0119]

[0120]

[0121] Dashed lines represent the sites of attachment of the groups.

[0122] R 51 、R 52 、R 53 Each is independently selected from any one of substituted or unsubstituted C6-C20 (e.g., C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) aryl, substituted or unsubstituted C3-C20 (e.g., C3, C4, C5, C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) heteroaryl, more preferably

[0123] Preferably, the first host material is selected from any one or a combination of at least two of the following compounds shown in P1-P102:

[0124]

[0125]

[0126]

[0127] Preferably, the first host material is a red light host material, which is selected from any one or a combination of at least two of the compounds shown in the aforementioned P1-P102.

[0128] Preferably, the first host material is a green light host material having a structure shown in Formula III. D Any one selected from the following substituted or unsubstituted groups:

[0129]

[0130] R 41 Preferably, it is any one of a substituted or unsubstituted C6-C20 (e.g., C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) aryl group, or a substituted or unsubstituted C3-C20 (e.g., C3, C4, C5, C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) heteroaryl group, and more preferably any one of a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a phenylnaphthyl group, a naphthylphenyl group, a dibenzofuranyl group, or a dibenzothiophenyl group.

[0131] R 61 Any one selected from C6-C20 (e.g., C6, C7, C8, C9, C10, C12, C14, C16, or C18, etc.) aryl, C3-C20 (e.g., C3, C4, C5, C6, C7, C8, C9, C10, C12, C14, C16, or C18, etc.) heteroaryl, further preferably any one selected from phenyl, biphenyl, terphenyl, naphthyl, phenylnaphthyl, naphthylphenyl, dibenzofuranyl, or dibenzothiophenyl.

[0132] More preferably, R as the green light host material D Any one selected from the following substituted or unsubstituted groups:

[0133]

[0134] Preferably, L3 as a green light host material is selected from any one of the following groups:

[0135] Preferably, Ar3 as a green light host material is selected from any one of the following substituted or unsubstituted groups:

[0136] R 51Preferably, it is any one of a substituted or unsubstituted C6-C20 (e.g., C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) aryl group, or a substituted or unsubstituted C3-C20 (e.g., C3, C4, C5, C6, C7, C8, C9, C10, C12, C14, C16 or C18, etc.) heteroaryl group, and more preferably any one of a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a dibenzofuranyl group, or a dibenzothiophenyl group.

[0137] Preferably, the first host material is a green light host material, wherein the green is selected from any one or a combination of at least two of the following compounds A1-A32:

[0138]

[0139]

[0140]

[0141] In a preferred technical solution of the present invention, the material of the mth organic functional layer (electron blocking layer) is selected from any one of E3, E5, E8, E10, E12, E16, E21, E25, E26, E28, E30, E33, E37, E39, E40, E42, E47, E49, E51, E56, and E58, or a combination of at least two thereof, and the first main material is selected from any one of P4, P8, P14, P17, P18, P24, P40, P47, P68, P75, P76, P83, and P91, or a combination of at least two thereof, and P8 is further preferred.

[0142] In a preferred technical solution of the present invention, the material of the mth organic functional layer (electron blocking layer) is selected from any one of E3, E8, E39, and E56, or a combination of at least two of them, and the first main material is selected from any one of A1, A11, A17, A20, A25, A28, and A32, or a combination of at least two of them.

[0143] Preferably, the light-emitting layer further comprises a second host material containing an electron-withdrawing group.

[0144] Preferably, the electron-withdrawing group comprises a triazine group.

[0145] Further preferably, the second host material is selected from the compound shown in the following N30:

[0146] Preferably, the mass ratio of the first host material to the second host material is (0.01-99):1, for example, 0.05:1, 0.1:1, 0.2:1, 0.3:1, 0.5:1, 0.7:1, 0.9:1, 1:1, 1.1:1, 1.3:1, 1.5:1, 1.7:1, 1.9:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1 or 90:1, etc., further preferably (0.1-10):1, further preferably (0.4-2.5):1, and further preferably (0.5-1.5):1.

[0147] Preferably, the light-emitting layer further includes a doping material, which is also called a "guest material", a "dye", or a "luminescent dye".

[0148] Preferably, the doping material is a phosphorescent doping material.

[0149] Preferably, based on the mass of the first main material as 100%, the mass of the doping material in the light-emitting layer is 0.1-10%, for example, it can be 0.2%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 7%, 8% or 9%, etc.

[0150] Preferably, a hole injection layer is further provided between the anode and the hole transport region.

[0151] Preferably, an electron transport region is provided between the light-emitting layer and the cathode.

[0152] Preferably, the electron transport region includes any one of a hole blocking layer, an electron transport layer, and an electron injection layer, or a combination of at least two of them.

[0153] Preferably, the organic electroluminescent device comprises an anode, a hole injection layer, a hole transport region, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer and a cathode which are arranged in sequence.

[0154] In a preferred technical solution, a substrate is provided on the side of the anode facing away from the organic layer or the side of the cathode facing away from the organic layer. The substrate is a rigid substrate or a flexible substrate having excellent mechanical strength, thermal stability, water resistance, and transparency. Exemplary rigid substrates include, but are not limited to, glass substrates and Si substrates, while exemplary flexible substrates include, but are not limited to, polyvinyl alcohol (PVA) films, polyimide (PI) films, and polyester (PET) films. The substrate of the present invention is preferably a rigid glass substrate.

[0155] In a preferred technical solution, the anode can be formed by sputtering or depositing a material used as the first electrode on a substrate. The anode is preferably a conductive compound, alloy, metal, or mixture of such materials with a large work function. Inorganic materials can be used, including metals, metal oxides, laminates formed by alternating metals and metals, laminates formed by alternating metals and non-metals, etc.; the metal oxides include indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), tin oxide (SnO), etc., and metals include gold, silver, copper, aluminum, etc. with a relatively high work function; the anode in the present invention is preferably ITO.

[0156] The organic layer can be formed on the electrode by vacuum evaporation, spin coating, printing, etc., or other methods, not limited to the above methods. In the preferred technical solution of the present invention, the device prepared by vacuum evaporation is described.

[0157] In a preferred embodiment, the hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can be made of one or more compounds H1-H40 described above, or one or more compounds HI-1 to HI-3 described below. Alternatively, one or more compounds H1-H40 can be doped with one or more compounds HI-1 to HI-3 described below.

[0158]

[0159] The doping material (phosphorescent doping material, guest material, dye) includes a green light material and can be selected from, but not limited to, one or more combinations of GPD-1 to GPD-47 listed below.

[0160]

[0161] Where D is deuterium.

[0162] In a preferred technical solution, the doping material (phosphorescent doping material, guest material, dye) includes a red light material, which can be selected from, but not limited to, one or more combinations of RPD-1 to RPD-28 listed below.

[0163]

[0164]

[0165] In a preferred technical solution, the material of the electron transport layer can be selected from, but not limited to, any one or a combination of at least two of the compounds ET-1 to ET-73 listed below.

[0166]

[0167]

[0168]

[0169]

[0170] In one aspect of the present invention, a hole blocking layer (HBL) is located between the electron transport layer and the light emitting layer. The hole blocking layer can be made of, but is not limited to, one or more compounds of the above ET-1 to ET-73.

[0171] In a preferred technical solution, the material of the electron injection layer includes but is not limited to one or more combinations of the following: LiQ, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca, Mg or Yb.

[0172] In a preferred technical solution, the cathode can be made of metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), ytterbium (Yb), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), and any combination thereof. It can also be made of metals such as ITO, metal mixtures, oxides, etc. The cathode of the present invention is preferably aluminum.

[0173] In a second aspect, the present invention provides a display device, comprising the organic electroluminescent device according to the first aspect.

[0174] Compared with the prior art, the present invention has the following beneficial effects:

[0175] In the organic electroluminescent device provided by the present invention, the mobility and HOMO energy levels of each organic functional layer in the hole transport region are designed and matched with each other, and are reasonably matched with the light-emitting layer, thereby improving the hole transport efficiency of the device, reducing the accumulation of excess holes, improving the balance between holes and electrons in the light-emitting layer, and achieving a good match between the number of holes and the number of electrons in the light-emitting layer, so that the device has the advantages of high luminous efficiency, low driving voltage and long life, and at the same time reducing the capacitance value of the device, avoiding the occurrence of the "screen ghosting" problem, thereby significantly improving the overall performance of the organic electroluminescent device. BRIEF DESCRIPTION OF THE DRAWINGS

[0176] Figure 1 A schematic structural diagram of an organic electroluminescent device provided in one embodiment of the present invention;

[0177] Figure 2 A schematic structural diagram of an organic electroluminescent device provided in another embodiment of the present invention;

[0178] Among them, 10-anode, 20-hole injection layer, 30-hole transport region, 31-hole transport layer, 31A-first hole transport layer, 31B-second hole transport layer, 32-electron blocking layer, 40-light-emitting layer, 50-hole blocking layer, 60-electron transport layer, 70-electron injection layer, 80-cathode. DETAILED DESCRIPTION

[0179] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0180] In a specific embodiment of the present invention, the structural diagram of the organic electroluminescent device is as follows: Figure 1 As shown, it includes an anode 10, a hole injection layer 20, a hole transport region 30, a light-emitting layer 40, a hole blocking layer 50, an electron transport layer 60, an electron injection layer 70 and a cathode 80 arranged in sequence; wherein the hole transport region 30 includes a hole transport layer 31 and an electron blocking layer 32, and the electron blocking layer 32 is arranged adjacent to the light-emitting layer 40.

[0181] The hole mobility of the hole transport layer 31 and the electron blocking layer 32 are μ1 and μ2 respectively, and μ1 and μ2 are independently ≥ 1.0×10 -4 cm 2 V -1 s -1 , and 1<μ1 / μ2≤2.

[0182] The HOMO energy levels of the hole transport layer 31 and the electron blocking layer 32 are HOMO1 and HOMO2 respectively; the light emitting layer 40 includes a first host material containing an electron donating group, and the HOMO energy level of the first host material is HOMO PH , then 0≤HOMO2-HOMO PH ≤0.40eV, preferably 0≤HOMO2-HOMO PH ≤0.30eV.

[0183] Preferably, -0.05 eV≤HOMO1−HOMO2≤0.15 eV, and more preferably, 0≤HOMO1−HOMO2≤0.10 eV.

[0184] In another specific embodiment of the present invention, the structural schematic diagram of the organic electroluminescent device is as follows Figure 2 As shown, it includes an anode 10, a hole injection layer 20, a hole transport region 30, a light-emitting layer 40, a hole blocking layer 50, an electron transport layer 60, an electron injection layer 70 and a cathode 80 arranged in sequence; wherein the hole transport region 30 includes a first hole transport layer 31A, a second hole transport layer 31B and an electron blocking layer 32 arranged in sequence, and the electron blocking layer 32 is arranged adjacent to the light-emitting layer 40.

[0185] The hole mobility of the first hole transport layer 31A, the second hole transport layer 31B and the electron blocking layer 32 are μ 1A 、μ 1B , μ2, then μ 1A 、μ 1B , μ2 are each independently ≥1.0×10 -4 cm 2 V -1 s -1 , and 1<μ 1A / μ 1B ≤2, 1<μ 1B / μ2≤2.

[0186] The HOMO energy levels of the first hole transport layer 31A, the second hole transport layer 31B, and the electron blocking layer 32 are HOMO 1A HOMO 1B , HOMO2; the light-emitting layer 40 includes a first host material containing an electron-donating group, and the HOMO energy level of the first host material is HOMO PH , then 0≤HOMO2-HOMO PH ≤0.40eV, preferably 0≤HOMO2-HOMO PH ≤0.30eV.

[0187] Preferably, -0.05eV≤HOMO 1A–HOMO 1B ≤0.15eV, more preferably 0≤HOMO 1A –HOMO 1B ≤0.10eV.

[0188] Preferably, -0.05eV≤HOMO 1B –HOMO2≤0.15eV, more preferably 0≤HOMO 1B –HOMO2≤0.10eV.

[0189] Example 1

[0190] An organic electroluminescent device, the structural diagram of which is as follows Figure 1 As shown, it includes an anode 10 (ITO / Ag / ITO), a hole injection layer 20, a hole transport layer 31, an electron blocking layer 32, a light-emitting layer 40, a hole blocking layer 50, an electron transport layer 60, an electron injection layer 70 and a cathode 80 (Al) arranged in sequence; its preparation method is as follows:

[0191] (1) On a glass substrate with an anode layer of ITO / Ag / ITO having a thickness of 150 nm, a vacuum evaporation method was used. When the vacuum degree was 2×10 -4 Each film layer was deposited at Pa; first, a hole injection layer, i.e., a H36:3% HI-3 film, was formed on ITO (H36 was 100%, and 3% was the doping ratio of HI-3 in the hole injection layer). The evaporation rate ratio of H36 to HI-3 was 1:0.03, and the evaporation rate of H36 was The thickness of the hole injection layer is 10 nm;

[0192] (2) Deposit 100nm of H36 as a hole transport layer on the hole injection layer at a deposition rate of

[0193] (3) Deposit 80nm of E39 as an electron blocking layer on the hole transport layer at a evaporation rate of

[0194] (4) A light-emitting layer was evaporated on the hole transport layer, i.e., P8:N30:RPD-1=100%:100%:3% (the first host material P8 was 100%, the doping ratio of the second host material N30 was 100%, and the doping ratio of the dye RPD-10 was 3%). The thickness of the light-emitting layer was 40 nm, and the evaporation rate ratio of P8, N30, and dye RPD-10 was 1:1:0.03. The evaporation rate of P8 was

[0195] (5) ET-31 with a thickness of 5 nm was vacuum-deposited on the light-emitting layer as a hole blocking layer. The ET-31 evaporation rate was

[0196] (6) ET-1:100% LiQ (ET-1 is 100%, and 100% is the doping ratio of LiQ) with a thickness of 25 nm was vacuum-deposited on the hole blocking layer as the electron transport layer. The ET-1 evaporation rate was

[0197] (7) Vacuum evaporate 1 nm of LiF on the electron transport layer as the electron injection layer at a rate of

[0198] (8) Vacuum-evaporating an Al layer with a thickness of 150 nm on the electron injection layer as a cathode to obtain the organic electroluminescent device.

[0199] Example 2-38

[0200] An organic electroluminescent device, which differs from Example 1 only in that the first host material of the hole transport layer, electron blocking layer, and light-emitting layer is replaced with the compounds shown in Table 1 and Table 3. The rest of the structure, materials, and preparation method of the device are the same as those in Example 1.

[0201] Examples 39-46

[0202] An organic electroluminescent device differs from Example 1 only in that the first host material of the first hole transport layer, the second hole transport layer, the electron blocking layer, and the first host material of the light-emitting layer are replaced with the compounds shown in Tables 1 and 4, the dye in the light-emitting layer is GPD-12, and its doping ratio is 10%. The rest of the structure, materials, and preparation method of the device are the same as those in Example 1.

[0203] Example 47

[0204] An organic electroluminescent device, the structural diagram of which is as follows Figure 2 As shown, it includes an anode 10 (ITO / Ag / ITO), a hole injection layer 20, a first hole transport layer 31A, a second hole transport layer 31B, an electron blocking layer 32, a light-emitting layer 40, a hole blocking layer 50, an electron transport layer 60, an electron injection layer 70 and a cathode 80 (Al) arranged in sequence; its preparation method is as follows:

[0205] (1) On a glass substrate with an anode layer of ITO / Ag / ITO having a thickness of 150 nm, a vacuum evaporation method was used. When the vacuum degree was 2×10 -4 Each film layer was deposited at 1000 Pa; first, a 10 nm hole injection layer was formed on the ITO, namely, a H36:3% HI-3 film, and the specific method was the same as in Example 1;

[0206] (2) Deposit 50nm of H36 on the hole injection layer as the first hole transport layer at a deposition rate of 50nm of H9 was deposited on the first hole transport layer as the second hole transport layer at a deposition rate of

[0207] (3) Deposit 80nm of E5 as an electron blocking layer on the second hole transport layer at a evaporation rate of

[0208] (4) A light-emitting layer with a composition of P8:N30:RPD-1 = 100%:100%:3% was deposited on the electron blocking layer to a thickness of 40 nm. The specific method was the same as in Example 1.

[0209] (5) Vacuum-deposit 5 nm of ET-31 as a hole blocking layer on the light-emitting layer, vacuum-deposit 25 nm of ET-1:100% LiQ as an electron transport layer on the hole blocking layer, vacuum-deposit 1 nm of LiF as an electron injection layer on the electron transport layer, and vacuum-deposit 150 nm of Al as a cathode on the electron injection layer. The specific method is the same as that in Example 1, thereby obtaining the organic electroluminescent device.

[0210] Examples 48-51

[0211] An organic electroluminescent device, which differs from Example 47 only in that the first host material of the first hole transport layer, the second hole transport layer, the electron blocking layer, and the first light-emitting layer are replaced with the compounds shown in Tables 2 and 3. The other structures, materials, and preparation methods of the device are the same as those in Example 47.

[0212] Comparative Examples 1-9

[0213] An organic electroluminescent device, which differs from Example 1 only in that the first host material of the hole transport layer, electron blocking layer, and light-emitting layer is replaced with the compounds shown in Tables 1 and 3 (the light-emitting layer dye is RPD-10). The other structures, materials, and preparation methods of the device are the same as those in Example 1.

[0214] Comparative Examples 10-12

[0215] An organic electroluminescent device, which differs from Example 39 only in that the first host material of the hole transport layer, electron blocking layer, and light-emitting layer is replaced by the compounds shown in Table 1 and Table 4 (the light-emitting layer dye is GPD-12). The other structures, materials, and preparation methods of the device are the same as those in Example 39.

[0216] The hole transport layer materials, electron blocking layer materials, and first host materials involved in Comparative Examples 1-12 are as follows:

[0217]

[0218]

[0219] The organic materials used in the specific embodiments of the present invention are tested in the following manner:

[0220] (1)HOMO level

[0221] Cyclic voltammetry was performed on the organic materials to be tested using an electrochemical workstation. The workstation used a three-electrode system with a platinum electrode as the working electrode, a platinum wire electrode as the counter electrode, and an Ag wire electrode as the reference electrode. 0.5 g of the sample to be tested was dissolved in 5 mL of ultra-dry tetrahydrofuran. Tetrabutylammonium perchlorate was used as the electrolyte salt. The sample was protected by nitrogen. The voltage range was -2 V to 2 V, the scan rate was 100 mV / s, and the number of scans was 2. On the CV curve, the peak value, i.e., the oxidation potential E, was read. ox , according to the same settings as above, test the oxidation potential E of ferrocene Fe Calculated HOMO = -((E ox -E Fe )+4.8).

[0222] In the above examples and comparative examples, the HOMO energy level of the electron blocking layer material is HOMO EB , the HOMO energy level of the first host material is HOMO PH , the HOMO energy level difference (HOMO EB –HOMO PH ) is denoted as ΔHOMO(EB-PH);

[0223] In Examples 1-46 and Comparative Examples 1-12, the HOMO energy level of the hole transport layer material is HOMO HT , the HOMO energy level difference (HOMO HT –HOMO EB ) is denoted as ΔHOMO(HT-EB);

[0224] In Examples 47-51, the HOMO energy levels of the first hole transport layer material and the second hole transport layer material are HOMO HT1 HOMO HT2 , the HOMO energy level difference (HOMO HT1 –HOMO HT2 ) is recorded as ΔHOMO(HT1-2); the HOMO energy level difference between the second hole transport layer material and the electron blocking layer material (HOMO HT2 –HOMO EB ) is recorded as ΔHOMO(HT2-EB).

[0225] (2) Hole mobility μ

[0226] The glass substrate coated with the ITO transparent conductive layer was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in an acetone / ethanol mixed solvent, baked in a clean environment until the water was completely removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam. The glass substrate with the anode was placed in a vacuum chamber and evacuated to a vacuum of less than 1×10 -5 A single-carrier device was fabricated by vacuum-evaporating a 10nm layer of a mixture of HT-4:HI-3 (97 / 3, w / w) onto the aforementioned anode layer, followed by a 150nm layer of the material to be tested, a 3nm layer of HI-3, and a 13nm layer of Mg:Ag (1:9). The IV characteristics of the single-carrier device were measured using a digital source meter and a luminance meter. The carrier mobility at 2.3V was calculated using the SCLC (space charge limited current) method for data accumulation and comparison.

[0227] In the above examples and comparative examples, the hole mobility of the electron blocking layer material is recorded as μ EB ;

[0228] In Examples 1-46 and Comparative Examples 1-12, the hole mobility of the hole transport layer material is recorded as μ HT In Examples 47-51, the hole mobility of the first hole transport layer material and the second hole transport layer material are μ HT1 、μ HT2 .

[0229] (3) Energy gap E g test

[0230] First, the electron blocking material is dissolved in dichloromethane liquid to prepare a sample of the material to be tested. Then, the UV-visible spectrophotometer is set to the appropriate absorption spectrum mode. Before the test, a baseline scan is performed using a dichloromethane solution to record the spectral data under the instrument background. Next, the sample is placed in the sample chamber and tested. The absorption spectrum of the sample will be displayed in the instrument, from which the corresponding wavelength of the absorption peak of the material can be obtained, that is, the UV-vis on-set Finally, using formula E g =1240 / UV-vis on-set The energy gap of the material is obtained by calculation.

[0231] The test results are shown in Table 1 and Table 2:

[0232] Table 1

[0233]

[0234]

[0235]

[0236] Table 2

[0237]

[0238] The performance test of the organic electroluminescent devices provided in Examples 1-51 and Comparative Examples 1-12 was conducted as follows:

[0239] (1) Under the same brightness, the driving voltage, current efficiency and device life of each organic electroluminescent device were measured using a PR 750 photoradiometer (Photo Research), an ST-86LA luminance meter (Beijing Normal University Photoelectric Instrument Factory) and a Keithley 4200 test system. Specifically, the voltage was increased at a rate of 0.1 V per second, and the brightness of the organic electroluminescent device was measured at 3000 cd / m 2 The voltage at this time is the driving voltage (V), and the current density at this time is measured at the same time. The ratio of brightness to current density is the current efficiency (CE, cd / A);

[0240] The test values ​​of the driving voltage and current efficiency of Example 1 are recorded as 100%, and the driving voltage and current efficiency of Examples 2-38, 47-51 and Comparative Examples 1-9 are the ratios of their respective test values ​​to the test values ​​of Example 1 (relative voltage, relative current efficiency). The test results are shown in Table 3. The test values ​​of the driving voltage and current efficiency of Example 39 are recorded as 100%, and the driving voltage and current efficiency of Examples 40-46 and Comparative Examples 10-12 are the ratios of their respective test values ​​to the test value of Example 39 (relative voltage, relative current efficiency). The test results are shown in Table 4.

[0241] (2) The test method for LT97 life is as follows: Use ST-86LA luminance meter (Beijing Normal University Photoelectric Instrument Factory) at 3000cd / m 2 At a brightness of 100°, a constant current was maintained, and the time it took for the brightness of the organic electroluminescent device to drop to 97% of the initial brightness was measured. The LT97 lifetime test value of Example 1 was recorded as 100%, and the LT97 lifetimes of Examples 2-38, 47-51, and Comparative Examples 1-9 were the ratios of their respective test values ​​to the test value of Example 1 (relative lifetime). The test results are shown in Table 3. The LT97 lifetime test value of Example 39 was recorded as 100%, and the LT97 lifetimes of Examples 40-46 and Comparative Examples 10-12 were the ratios of their respective test values ​​to the test value of Example 39 (relative lifetime). The test results are shown in Table 4.

[0242] (3) The device capacitance test method is as follows: The device capacitance test is performed using a VersaSTAT3 device from Princeton Applied Research (PAR). The specific steps are as follows: Place the vapor-deposited sample in the device and connect the device cathode and anode to the device cathode. Enter the frequency, voltage and other parameters on the control interface, set the starting frequency to 5000Hz, the final frequency to 5000Hz, and the amplitude to 250; also set the starting voltage to -2V and the final voltage to 5V. After completing the settings, run the software device to obtain the corresponding voltage-capacitance data curve; select the maximum value of the curve capacitance data (capacitance peak) as the capacitance data of the device structure; the test value of the capacitance peak of Example 1 is recorded as 100%, and the capacitance peaks of Examples 2-38, 47-51 and Comparative Examples 1-9 are the ratios of their respective test values ​​to the test value of Example 1 (relative capacitance); the test value of the capacitance peak of Example 39 is recorded as 100%, and the capacitance peaks of Examples 40-46 and Comparative Examples 10-12 are the ratios of their respective test values ​​to the test value of Example 39 (relative capacitance). The test results are shown in Table 4.

[0243] Table 3

[0244]

[0245]

[0246]

[0247] Table 4

[0248]

[0249]

[0250] Combining the data in Tables 1, 2, 3, and 4, it can be seen that the organic electroluminescent device provided by the present invention adopts a specific hole transport region design, so that the hole transport region includes at least two organic functional layers, namely, at least one hole transport layer (HTL) and one electron blocking layer (EBL), wherein the EBL is adjacent to the light-emitting layer; under the same test conditions, the hole mobility of each layer in the hole transport region is ≥1.0×10 -4 cm 2 V -1 s -1, and along the first direction (the direction from anode to cathode), the hole mobility decreases, and the ratio of the hole mobility of two adjacent layers is ≤2; through the design of hole mobility, the design and matching of the HOMO energy levels between adjacent layers, while ensuring efficient light emission of the device, the number of excess holes is reduced, the possibility of hole accumulation at various organic interfaces is reduced, and ultimately the efficiency and stability of the device are improved, and the device capacitance value is effectively reduced, reducing the possibility of afterimages on the screen to improve the yield. Therefore, the organic electroluminescent device provided by Examples 1-51 of the present invention has significantly reduced capacitance while ensuring higher current efficiency, longer life and lower driving voltage, reducing the possibility of "smearing" on the screen, reducing process costs, and improving the finished product yield of the OLED display device.

[0251] In Tables 3 and 4, the analysis of Comparative Examples 1, 2, 7, or 10 shows that the hole mobility difference between the hole transport material and the electron blocking material is too large, and the hole mobility difference of the electron blocking layer material reduces the mobility difference between the EBL / EML, which can promote the transmission of holes from the electron blocking layer to the main luminescent layer, and the peak capacitance does not increase significantly. However, this slows the transfer of holes from the hole transport layer to the electron blocking layer, reducing the total amount of holes reaching the luminescent layer, resulting in carrier imbalance in the device, and thus an overall decrease in device voltage, efficiency, and lifespan performance. Comparative Examples 3, 6, 8, or 11 show that the hole mobility difference between the hole transport material and the electron blocking material is too small, and the mobility of the electron blocking layer is too high, forming a large mobility difference with the main luminescent layer, resulting in blocked hole accumulation between the two film layers, an increase in peak capacitance, and an inability to effectively transmit holes to the luminescent layer, resulting in a hole shortage and electron accumulation on the other side, which causes a voltage increase and a decrease in efficiency. In Comparative Examples 4 and 5, the hole mobility difference between the hole transport material and the electron blocking material is moderate, allowing holes to move relatively efficiently. However, due to the large energy level difference between the electron blocking layer and the P-type host in the light-emitting layer, holes accumulate at the interface between the light-emitting layer and the electron blocking layer, resulting in increased capacitance. Furthermore, since holes cannot effectively enter the light-emitting layer, device performance deteriorates. In Comparative Examples 9 and 12, the electron blocking layer material has low mobility, preventing effective hole transport. This results in high overall device voltage, carrier imbalance, reduced efficiency, and poor lifetime.

[0252] The applicant states that while the present invention uses the aforementioned embodiments to illustrate the organic electroluminescent device and its applications, the present invention is not limited to the aforementioned process steps, nor does it necessarily rely on the aforementioned process steps for implementation. Persons skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises an anode, a cathode, and a light-emitting layer disposed between the anode and the cathode, a hole transport region is disposed between the light-emitting layer and the anode, and the hole transport region comprises m organic functional layers, where m is selected from an integer ≥ 2; The hole mobility of each organic functional layer in the hole transport region is independently ≥1.0×10 -4 cm 2 V -1 s -1 ; The direction from the anode to the cathode is taken as the first direction, and the organic functional layers are numbered in sequence according to the first direction. The hole mobility of the xth organic functional layer is μ x , the hole mobility of the x+1th organic functional layer is μ x+1 , 1<μ x / μ x+1 ≤2; where x is an integer from 1 to m-1; The HOMO energy level of the mth organic functional layer is HOMO m The light-emitting layer includes a first host material containing an electron-donating group, and the HOMO energy level of the first host material is HOMO PH ; 0≤HOMO m -HOMO PH ≤0.40eV.

2. The organic electroluminescent device according to claim 1, wherein 0≤HOMO m -HOMO PH ≤0.30eV。 3. The organic electroluminescent device according to claim 1, wherein The HOMO energy level of the x-th organic functional layer is HOMO x , the HOMO energy level of the x+1th organic functional layer is HOMO x+1 , -0.05eV≤HOMO x -HOMO x+1 ≤0.15eV; Preferably, 0≤HOMO x -HOMO x+1 ≤0.10eV.

4. The organic electroluminescent device according to claim 1, wherein The energy gap of the material of the mth organic functional layer is ≤3.2 eV.

5. The organic electroluminescent device according to claim 1, wherein The materials of the first organic functional layer to the m-1th organic functional layer in the hole transport region independently have a structure as shown in Formula I: wherein Y1 and Y2 are each independently selected from any one of a single bond, O, S, CR1R2 or NR3, and at most one of Y1 and Y2 is a single bond; R1, R2, and R3 are each independently selected from any one of hydrogen, substituted or unsubstituted C1-C20 straight or branched alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl; R1 and R2 are not connected or are connected to form a ring by a chemical bond; L 11 , L 12 Each is independently selected from any one of a single bond, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C3-C30 heteroarylene group; Ar 11 、Ar 12 Each is independently selected from any one of a substituted or unsubstituted C6-C30 aryl group and a substituted or unsubstituted C3-C30 heteroaryl group; R1, R2, R3, L 11 , L 12 、Ar 11 、Ar 12 The substituents substituted therein are each independently selected from any one of halogen, cyano, nitro, hydroxyl, amino, carboxyl, thiol, C1-C20 straight or branched alkyl, C2-C20 alkenyl, C3-C20 cycloalkyl, C2-C20 heterocycloalkyl, C6-C30 aryl, C3-C30 heteroaryl, C6-C30 aryloxy, C3-C30 heteroaryloxy, C6-C30 arylamino, and C3-C30 heteroarylamino, or a combination of at least two thereof.

6. The organic electroluminescent device according to claim 5, characterized in that: The Y1 is selected from any one of O, S or CR1R2; and / or, the Y2 is selected from any one of a single bond, O, S or CR1R2; Preferably, R1 and R2 are each independently selected from any one of a substituted or unsubstituted C1-C10 straight or branched alkyl group, a substituted or unsubstituted C2-C10 alkenyl group, and a substituted or unsubstituted C6-C20 aryl group; Preferably, the L 11 , L 12 Each is independently selected from a single bond, a substituted or unsubstituted group: Dashed lines represent the attachment sites of the groups; Y3 is selected from O, S, CR 11 R 12 or NR 13 Any of the following; R 11 、R 12 、R 13 Each is independently selected from any one of hydrogen, C1-C20 straight or branched alkyl, C2-C20 alkenyl, C6-C30 aryl or C3-C30 heteroaryl; the R 11 and R 12 They are not connected or connected to form a ring through chemical bonds; Preferably, the L 11 Selected from Among them, -* represents the connection site between the group and N, -# represents the connection site between the group and Ar 11 The attachment site; Preferably, the L 12 Selected from single bonds, Dashed lines represent the attachment sites of the groups; Preferably, the Ar 11 、Ar 12 Each is independently selected from any one of the following substituted or unsubstituted groups: Dashed lines represent the sites of attachment of the groups.

7. The organic electroluminescent device according to claim 5, characterized in that: The materials of the first to m-1th organic functional layers in the hole transport region are independently selected from any one or a combination of at least two of the following compounds H1-H40:

8. The organic electroluminescent device according to claim 1, wherein The material of the mth organic functional layer has a structure as shown in Formula II: Wherein, L2 is selected from any one of a single bond, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C3-C30 heteroarylene group; Ar 21 、Ar 22 、Ar 23 Each is independently selected from any one of a substituted or unsubstituted C6-C30 aryl group and a substituted or unsubstituted C3-C30 heteroaryl group; R 21 Any one selected from substituted or unsubstituted C1-C20 straight or branched alkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl; adjacent R 21 are not connected or connected to form a ring through chemical bonds, the R 21 Not connected to adjacent ring structures or connected to form a ring through chemical bonds; L2、Ar 21 、Ar 22 、Ar 23 、R 21 The substituents substituted in the above-mentioned group are each independently selected from any one or a combination of at least two of halogen, cyano, nitro, hydroxyl, amino, carboxyl, C1-C20 straight or branched alkyl, C2-C20 alkenyl, C1-C20 alkoxy, C1-C20 alkylsilyl, C1-C20 alkylamino, C3-C20 cycloalkyl, C2-C20 heterocycloalkyl, C6-C30 aryl, C3-C30 heteroaryl, C6-C30 aryloxy, C3-C30 heteroaryloxy, C6-C30 arylamino, and C3-C30 heteroarylamino; n is an integer selected from 0-4.

9. The organic electroluminescent device according to claim 8, characterized in that: The material of the mth organic functional layer has a structure as shown in Formula IIA or Formula IIB: Among them, L2, Ar 21 、Ar 22 、Ar 23 Having the same defined range as in Formula II; R 22 、R 23 are each independently selected from any one of hydrogen, substituted or unsubstituted C1-C20 straight or branched alkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl; the R 22 、R 23 Each independently is not connected to the adjacent ring structure or is connected to form a ring through a chemical bond; Preferably, the R 22 and R 23 One of them is hydrogen, and the other is selected from any one of the following substituted or unsubstituted groups: Dashed lines represent the sites of attachment of the groups.

10. The organic electroluminescent device according to claim 8 or 9, characterized in that: The L2 is selected from any one of the following groups: Dashed lines represent the attachment sites of the groups; Preferably, the Ar 23 It has the structure shown in formula a: The Ar 23 Connected to L2 through any available site; X1 and X2 are each independently selected from a single bond, O, S, CR 31 R 32 or NR 33 Any one of , and at most one of X1 and X2 is a single bond; R 31 、R 32 、R 33 Each is independently selected from any one of hydrogen, C1-C20 straight or branched alkyl, C2-C20 alkenyl, C6-C30 aryl or C3-C30 heteroaryl; the R 31 and R 32 They are not connected or connected to form a ring through chemical bonds; Preferably, the Ar 23 Selected from Dashed lines represent the attachment sites of the groups; Preferably, the Ar 21 、Ar 22 Each is independently selected from any one of the following substituted or unsubstituted groups: Dashed lines represent the sites of attachment of the groups.

11. The organic electroluminescent device according to claim 1 or 8, characterized in that: The material of the mth organic functional layer is selected from any one or a combination of at least two of the following compounds E1-E59:

12. The organic electroluminescent device according to claim 1, wherein The first host material has a structure as shown in Formula III: RD-L3-Ar3 Formula III; Wherein, L3 is selected from any one of a single bond, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C3-C30 heteroarylene group; Ar3 is selected from any one of a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C30 heteroaryl group, a substituted or unsubstituted C6-C40 arylamino group, a substituted or unsubstituted C3-C40 heteroarylamino group, a substituted or unsubstituted C6-C40 arylsilyl group, and a substituted or unsubstituted C3-C40 heteroarylsilyl group; R D Any one selected from the following substituted or unsubstituted groups: Dashed lines represent the attachment sites of the groups; R 41 Each is independently selected from any one of a substituted or unsubstituted C1-C20 straight or branched alkyl group, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C3-C30 heteroaryl group; L3, Ar3, R D 、R 41 The substituents substituted therein are each independently selected from any one of halogen, cyano, nitro, hydroxyl, amino, carboxyl, C1-C20 straight or branched alkyl, C2-C20 alkenyl, C1-C20 alkoxy, C1-C20 alkylsilyl, C1-C20 alkylamino, C3-C20 cycloalkyl, C2-C20 heterocycloalkyl, C6-C30 aryl, C3-C30 heteroaryl, C6-C30 aryloxy, C3-C30 heteroaryloxy, C6-C30 arylamino, and C3-C30 heteroarylamino, or a combination of at least two thereof.

13. The organic electroluminescent device according to claim 12, characterized in that: The L3 is selected from any one of a single bond, a substituted or unsubstituted group: Preferably, Ar3 is selected from any one of the following substituted or unsubstituted groups: Dashed lines represent the attachment sites of the groups; R 51 、R 52 、R 53 Each is independently selected from any one of a substituted or unsubstituted C6-C20 aryl group and a substituted or unsubstituted C3-C20 heteroaryl group.

14. The organic electroluminescent device according to claim 1 or 12, characterized in that: The first host material is selected from any one or a combination of at least two of the following compounds shown in P1-P102:

15. The organic electroluminescent device according to claim 1, characterized in that The first host material is selected from any one or a combination of at least two of the following compounds A1-A32:

16. The organic electroluminescent device according to claim 1, characterized in that: The light-emitting layer further comprises a second host material containing an electron-withdrawing group; Preferably, the mass ratio of the first host material to the second host material is (0.01-99):1, preferably (0.1-10):1, further preferably (0.4-2.5):1; Preferably, the light-emitting layer further includes a doping material; Preferably, the doping material is a phosphorescent doping material.

17. The organic electroluminescent device according to claim 1, characterized in that: A hole injection layer is further provided between the anode and the hole transport region; Preferably, an electron transport region is further provided between the light-emitting layer and the cathode; Preferably, the electron transport region comprises any one of a hole blocking layer, an electron transport layer, and an electron injection layer, or a combination of at least two thereof; Preferably, the organic electroluminescent device comprises an anode, a hole injection layer, a hole transport region, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer and a cathode which are arranged in sequence.

18. A display device, characterized in that: The display device comprises the organic electroluminescent device according to any one of claims 1 to 17.

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