Organic electroluminescent device and display device

Abstract

The present invention relates to an organic electroluminescent device and a display device, wherein the organic electroluminescent device comprises an anode layer, a cathode layer and an organic layer arranged between the anode layer and the cathode layer; the organic layer contains compound I and compound II. The present invention uses compound I and compound II as materials of the organic layer at the same time, wherein compound I can adjust the carrier distribution inside the light-emitting layer, thereby regulating the carrier recombination area, and has a higher spatial stacking structure, and at the same time, compound II has a higher molecular plane expansion characteristic, thereby realizing faster hole transfer, improving hole mobility, and having a higher triplet energy level, which can block excess excitons, and the two are used together to effectively improve the efficiency of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of organic electroluminescence, and in particular to an organic electroluminescence device and a display apparatus. Background Art

[0002] The core of organic electroluminescent (OLED) devices is a thin film structure containing a variety of organic functional materials. Common functionalized organic materials include: hole injection materials, hole transport materials, hole blocking materials, electron injection materials, electron transport materials, electron blocking materials, luminescent host materials and luminescent guest (dyes), etc. When electricity is turned on, electrons and holes are injected and transported to the luminescent area respectively and recombine there, thereby generating excitons and emitting light.

[0003] In recent years, people in the industry have been constantly trying and exploring to improve device efficiency and stability. Most of them are seeking new materials to improve device performance. A large number of novel materials have been developed for use in organic electroluminescent devices. Although they have improved device performance to a certain extent, there is still a large amount of carrier accumulation at the interface, and there is also the problem of low device efficiency.

[0004] Therefore, there is an urgent need to develop organic electroluminescent devices with higher performance in this field. Summary of the invention

[0005] In view of the shortcomings of the prior art, one of the purposes of the present invention is to provide an organic electroluminescent device having high efficiency.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] The present invention provides an organic electroluminescent device, which comprises an anode layer, a cathode layer and an organic layer arranged between the anode layer and the cathode layer;

[0008] The organic layer contains compound I and compound II;

[0009]

[0010] The Ar 1 and Ar 2 Independently selected from substituted or unsubstituted C6-C30 aryl or substituted or unsubstituted C3-C30 heteroaryl;

[0011] The L 1 is selected from a substituted or unsubstituted C6-C30 arylene group or a substituted or unsubstituted C3-C30 heteroarylene group;

[0012] The L 2One selected from a single bond, a substituted or unsubstituted C6-C30 arylene group, or a substituted or unsubstituted C3-C30 heteroarylene group;

[0013] The R 1 , R 2 and R 3 Independently selected from any one of substituted or unsubstituted C1-C20 chain alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl;

[0014] The m is an integer from 0 to 6, such as 1, 2, 3, 4, 5, etc.;

[0015] The R 4 Independently selected from any one of substituted or unsubstituted C1-C20 chain alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, and substituted or unsubstituted C6-C30 aryl;

[0016] The compound II is a compound formed by replacing at least one (e.g., 2, 3, 4, 5, etc.) Rx at any substitutable position on the structure shown in formula (3); Rx can replace the naphthalene ring, Ar 3 To Ar 5 , L 3 -L 5 and R 5 Any one of them can be substituted;

[0017]

[0018] The r is an integer from 0 to 6, such as 1, 2, 3, 4, 5, etc.;

[0019] The Ar 3 To Ar 5 Independently selected from substituted or unsubstituted C6-C30 aryl or substituted or unsubstituted C3-C30 heteroaryl;

[0020] The L 3 -L 5 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;

[0021] The R 5Independently selected from any one of substituted or unsubstituted C1-C20 chain alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl;

[0022] The Rx is selected from a substituted or unsubstituted C3-C20 cycloalkyl group;

[0023] Ar 1 To Ar 5 , L 1 To L 5 , R 1 , R 2 , R 3 , R 4 , R 5 In Rx, the substituted groups are independently selected from one or a combination of at least two of halogen, C1-C10 chain alkyl, C3-C10 cycloalkyl, C1-C10 alkoxy, C1-C10 thioalkoxy, C6-C30 arylamino, C3-C30 heteroarylamino, C6-C30 monocyclic aromatic group, C10-C30 condensed aromatic group, C3-C30 monocyclic heteroaryl group, and C6-C30 condensed heteroaryl group.

[0024] The above-mentioned "substituted or unsubstituted" group may be substituted with one substituent or with multiple substituents. When there are multiple substituents, they may be selected from different substituents. When the same expressions are involved in the present invention, they all have the same meaning, and the selection range of the substituents is as shown above and will not be repeated one by one.

[0025] In the present invention, the expression of chemical elements includes the concept of isotopes with the same chemical properties. For example, hydrogen (H) includes 1 H (protium or H), 2 H (deuterium or D), etc.; Carbon (C) includes 12 C. 13 C, etc.

[0026] In the present invention, the heteroatom of the heteroaryl group is usually selected from N, O, and S.

[0027] 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.

[0028] The above-mentioned C1-C20 chain alkyl group is preferably a C1-C10 chain alkyl group, and more preferably a C1-C6 chain alkyl group, examples of which include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-hexyl, n-octyl, n-pentyl, n-heptyl, n-nonyl, n-decyl, etc.

[0029] The above-mentioned C3-C20 cycloalkyl group is preferably cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.

[0030] The substituted or unsubstituted C6-C30 (ene) aryl group is preferably a C6-C20 aryl group, and the aryl group is preferably phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthrenyl, indenyl, fluorenyl and its derivatives, fluoranthenyl, triphenylene, pyrenyl, peryl, The biphenyl group is selected from the group consisting of 2-biphenyl, 3-biphenyl and 4-biphenyl; the terphenyl group includes p-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-2-yl, m-terphenyl-4-yl, m-terphenyl-3-yl and m-terphenyl-2-yl; the naphthyl group includes 1-naphthyl or 2-naphthyl; the anthracenyl group is selected from the group consisting of 1-anthracenyl, 2-anthracenyl and 9-anthracenyl. ; The fluorenyl group is selected from the group consisting of 1-fluorenyl, 2-fluorenyl, 3-fluorenyl, 4-fluorenyl and 9-fluorenyl; the fluorenyl derivative is selected from the group consisting of 9,9'-dimethylfluorene, 9,9'-spirobifluorene and benzofluorene; the pyrenyl group is selected from the group consisting of 1-pyrenyl, 2-pyrenyl and 4-pyrenyl; the naphthyl group is selected from the group consisting of 1-naphthyl, 2-naphthyl and 9-naphthyl.

[0031] In the present invention, the aryl group includes a monocyclic aryl group and a condensed-ring aryl group, and the heteroaryl group also includes a monocyclic heteroaryl group and a condensed-ring heteroaryl group.

[0032] The above-mentioned substituted or unsubstituted C3-C30 (sub) heteroaryl group is preferably a C4-C20 heteroaryl group, and the heteroaryl group is preferably a furyl group, a thienyl group, a pyrrolyl group, a benzofuranyl group, a benzothienyl group, an isobenzofuranyl group, an indolyl group, a dibenzofuranyl group, a dibenzothienyl group, a carbazole group and derivatives thereof, wherein the carbazole derivative is preferably 9-phenylcarbazole, 9-naphthylcarbazole, benzocarbazole, dibenzocarbazole, or indolecarbazole.

[0033] The above-mentioned C6-C30 arylamino group refers to a group formed by connecting an aryl group and an amino group, and the connecting bond may be on the amino group or on the aryl group. The same is true for the C3-C30 heteroarylamino group.

[0034] The present invention adopts both compound I and compound II as materials for the organic layer, wherein compound I can adjust the carrier distribution inside the light-emitting layer, thereby regulating the carrier recombination area, and has a relatively high spatial stacking structure, while compound II has relatively high molecular plane unfolding characteristics, thereby achieving faster hole transfer and improving hole mobility, and has relatively high triplet energy levels, which can block excess excitons. The combination of the two can effectively improve the efficiency of the device.

[0035] Preferably, the compound I has any one of the structures shown in P1-P777.

[0036] Preferably, the compound II has any one of the structures shown in A1 to A291.

[0037] Preferably, the organic layer includes a light-emitting layer and an electron blocking layer.

[0038] Preferably, the light-emitting layer contains compound I, and the electron blocking layer contains compound II.

[0039] Preferably, the light-emitting layer contains compound II, and the electron blocking layer contains compound I.

[0040] In the preferred technical solution of the present invention, compound I and compound II are used as a light-emitting layer material and an electron blocking layer material respectively. This is because both materials have hole transport properties and are used as materials for the electron blocking layer and the light-emitting layer respectively, which can balance the effects of faster electron transfer, so that the location of the recombination center occurs in the center of the light-emitting layer, thereby further improving the device efficiency.

[0041] Preferably, the light-emitting layer contains a first host material, a second host material and a doping material;

[0042] The first host material is compound I, and the electron blocking layer contains compound II; alternatively, the first host material is compound II, and the electron blocking layer contains compound I.

[0043] Furthermore, the present invention preferably uses compound I or compound II as one of the main materials in the dual-main light-emitting layer, which can better adjust the carrier distribution inside the light-emitting layer, thereby regulating the carrier recombination area, and has a higher spatial stacking structure. As one of the dual hosts, it can improve the light extraction efficiency. In combination with other main materials, it can further improve the efficiency under low grayscale and reduce the degree of efficiency roll-off of the device, thereby further improving the efficiency of the device.

[0044] Preferably, the mass percentage of the first main material to the second main material is 1%-150%, for example 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, 140%, 145%, etc., preferably 10%-100%.

[0045] In another preferred technical solution of the present invention, the addition amount of compound I or compound II in the dual-host light-emitting layer is selected to be within the above-mentioned specific range. Within this range, the efficiency of the device can be further improved. Too high an addition amount will lead to too fast hole transport, which will destroy the balance inside the device. Too low an addition amount will have no regulatory effect.

[0046] Preferably, the second host material comprises a phosphorescent material.

[0047] Preferably, the thickness of the light-emitting layer is 10-60 nm, for example, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, etc., preferably 20-50 nm.

[0048] The present invention preferably contains compound I or compound II, and the thickness of the light-emitting layer is 10-60nm. Within this thickness range, the efficiency of the device can be further improved. Too small a thickness will result in the failure of sufficient recombination of internal excitons, while too large a thickness will result in a longer hole and electron transport process and more internal losses, both of which will reduce efficiency.

[0049] Preferably, the thickness of the electron blocking layer is 2-100 nm, for example, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, etc., preferably 3-90 nm.

[0050] The present invention preferably contains compound I or compound II, and the thickness of the electron blocking layer is 2-100nm. Within this thickness range, the efficiency of the device can be further improved. Too small a thickness will result in the failure of internal excitons to fully recombine, while too large a thickness will result in a longer hole and electron transport process and more internal losses, both of which will reduce efficiency.

[0051] Preferably, the organic layer further includes a hole injection layer, a hole transport layer, an electron transport layer and an electron injection layer.

[0052] Preferably, in compound I, Ar 1 Any one selected from the following substituted or unsubstituted groups: phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthracenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, 9,9-dimethylfluorenyl, 9,9-diphenylfluorenyl, spirofluorenyl, triphenylene, fluoranthenyl, benzo-9,9-dimethylfluorenyl, benzospirofluorenyl.

[0053] Preferably, in compound I, Ar 2Any one selected from the following substituted or unsubstituted groups: phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthracenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, 9,9-dimethylfluorenyl, 9,9-diphenylfluorenyl, spirofluorenyl, triphenylene, fluoranthenyl, benzo-9,9-dimethylfluorenyl, benzospirofluorenyl, preferably substituted or unsubstituted naphthyl.

[0054] Preferably, the Ar 2 Any one selected from the following substituted or unsubstituted groups:

[0055]

[0056] The dashed lines represent the bonds connecting the groups.

[0057] Preferably, in compound I, the R 1 , R 2 and R 3 Independently selected from one of methyl, ethyl or phenyl, preferably all of them are methyl.

[0058] Preferably, in compound I, the L 1 One selected from the following substituted or unsubstituted groups: one of phenylene, biphenylene, naphthylene, dibenzofuranylene, dibenzothiophenylene and 9,9-dimethylfluorenylene.

[0059] Preferably, in compound I, the L 2 One selected from a single bond, a substituted or unsubstituted C6-C20 arylene group or a substituted or unsubstituted C3-C20 heteroarylene group, preferably a single bond or a phenylene group.

[0060] Preferably, the compound II is a compound formed by substituting at least one Rx at any substitutable position on the structure represented by formula (3-1);

[0061]

[0062] In formula (3-1), the r, Ar 3 To Ar 5 , L 3 -L 5 , R 5 , Rx have the same selection range as in formula (3).

[0063] Preferably, the Rx is selected from any one of the following groups:

[0064]

[0065] The wavy line or * mark represents the connecting bond of the group.

[0066] Preferably, the Ar 3 To Ar 5 Each is independently selected from any one of the following substituted or unsubstituted groups:

[0067]

[0068]

[0069] The dotted lines represent the connecting bonds of the groups.

[0070] Preferably, the L 3 and L 4 Each is independently selected from a single bond, a phenylene group or a naphthylene group, preferably a single bond.

[0071] Preferably, the L 5 For a single key.

[0072] OLED includes a first electrode, a second electrode, and an organic material layer between the electrodes. The organic material can be divided into multiple regions. For example, the organic material layer can include a hole transport region, a light emitting layer, and an electron transport region.

[0073] In a specific embodiment, a substrate may be used below the first electrode or above the second electrode. The substrate is a glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. In addition, a thin film transistor (TFT) may also be provided on the substrate used as a display.

[0074] The first electrode can be formed by sputtering or depositing the material used as the first electrode on the substrate. When the first electrode is used as an anode, an oxide transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO) and any combination thereof can be used. When the first electrode is used as a cathode, a metal or alloy 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 can be used.

[0075] The organic material layer can be formed on the electrode by vacuum thermal evaporation, spin coating, printing, etc. The compound used as the organic material layer can be organic small molecules, organic macromolecules and polymers, and combinations thereof.

[0076] The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a single-layer hole transport layer (HTL), including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds. The hole transport region can also be a multilayer structure including at least one layer of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL); wherein the HIL is located between the anode and the HTL, and the EBL is located between the HTL and the light-emitting layer.

[0077] The material of the hole transport region can be selected from, but not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives, wherein the aromatic amine derivatives are compounds shown as HT-1 to HT-51 below; or any combination thereof.

[0078]

[0079]

[0080]

[0081] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can use one or more compounds of HT-1 to HT-51 above, or one or more compounds of HI-1 to HI-3 below; or one or more compounds of HT-1 to HT-51 can be doped with one or more compounds of HI-1 to HI-3 below.

[0082]

[0083] The light-emitting layer includes a light-emitting dye (i.e., dopant) that can emit different wavelength spectra, and may also include a host material (Host). The light-emitting layer can be a monochrome light-emitting layer that emits a single color such as red, green, and blue. A plurality of monochrome light-emitting layers of different colors can be arranged in a plane according to a pixel pattern, or they can be stacked together to form a color light-emitting layer. When light-emitting layers of different colors are stacked together, they can be separated from each other or connected to each other. The light-emitting layer can also be a single color light-emitting layer that can simultaneously emit different colors such as red, green, and blue.

[0084] Depending on the technology, the light-emitting layer material can be phosphorescent electroluminescent material. In an OLED device, a single light-emitting technology can be used, or a combination of multiple different light-emitting technologies can be used. These different light-emitting materials classified by technology can emit light of the same color or different colors.

[0085] In one aspect of the present invention, the second host material of the light-emitting layer is a phosphorescent material, and the phosphorescent material is selected from, but not limited to, one or more combinations of PH-1 to PH-86.

[0086]

[0087]

[0088]

[0089]

[0090] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of GPD-1 to GPD-47 listed below.

[0091]

[0092]

[0093]

[0094] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of RPD-1 to RPD-28 listed below.

[0095]

[0096]

[0097] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of YPD-1 to YPD-11 listed below.

[0098]

[0099] In one aspect of the present invention, the light-emitting layer adopts the technology of thermally activated delayed fluorescence luminescence. The main material of the light-emitting layer is selected from, but not limited to, one or more combinations of the above PH-1 to PH-86.

[0100] In one aspect of the present invention, an electron blocking layer (EBL) is located between the hole transport layer and the light emitting layer. The electron blocking layer may be one or more compounds included in the above-mentioned compound I and compound II, but is not limited thereto.

[0101] The OLED organic material layer may further include an electron transport region between the light emitting layer and the cathode. The electron transport region may be a single-layer electron transport layer (ETL), including a single-layer electron transport layer containing only one compound and a single-layer electron transport layer containing multiple compounds. The electron transport region may also be a multi-layer structure including at least one layer of an electron injection layer (EIL) and an electron transport layer (ETL).

[0102] In one aspect of the present invention, the electron transport layer material can be selected from, but not limited to, one or more combinations of ET-1 to ET-65 listed below.

[0103]

[0104]

[0105]

[0106]

[0107] The device may further include an electron injection layer located between the electron transport layer and the cathode. Materials for the electron injection layer include, but are not limited to, one or more combinations of the following.

[0108] LiQ, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca, Mg, Yb.

[0109] The second object of the present invention is to provide a display device, wherein the display device contains the organic electroluminescent device described in the first object.

[0110] Compared with the prior art, the present invention has the following beneficial effects:

[0111] The present invention adopts both compound I and compound II as materials for the organic layer, wherein compound I can adjust the carrier distribution inside the light-emitting layer, thereby regulating the carrier recombination area, and has a relatively high spatial stacking structure, while compound II has relatively high molecular plane unfolding characteristics, thereby achieving faster hole transfer and improving hole mobility, and has relatively high triplet energy levels, which can block excess excitons. The combination of the two can effectively improve the efficiency of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0112] Figure 1 is a schematic structural diagram of an organic electroluminescent device provided in a specific embodiment of the present invention;

[0113] Among them, 1-glass substrate with anode, 2-hole injection layer, 3-hole transport layer, 4-electron blocking layer, 5-light-emitting layer, 6-electron transport layer, 7-electron injection layer, 8-cathode layer, 9-external power supply. DETAILED DESCRIPTION

[0114] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0115] In the present invention, the synthesis methods of compound I and compound II are both prior arts, wherein the synthesis method of compound I refers to patent application 202010394523.4, and the synthesis method of compound II refers to patent application 201910857132.9.

[0116] Example 1

[0117] This embodiment provides an organic electroluminescent device, the structure of which is as follows: Figure 1 As shown, it includes a glass substrate 1 with an anode, a hole injection layer 2, a hole transport layer 3, an electron blocking layer 4, a light-emitting layer 5, an electron transport layer 6, an electron injection layer 7, a cathode layer 8 and an external power source 9.

[0118] The preparation method of the organic electroluminescent device is as follows:

[0119] The glass plate coated with the ITO transparent conductive layer was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone:ethanol, baked in a clean environment to completely remove the water, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam;

[0120] The glass substrate with the anode is placed in a vacuum chamber, and the vacuum is evacuated to <1×10-5Pa. On the anode layer, 10nm of HT-4:HI-3 (97 / 3, w / w) mixture is vacuum-evaporated in sequence as a hole injection layer, 60nm of compound HT-4 as a hole transport layer, 60nm of compound A1 as an electron blocking layer; 30nm of compound PH86:P1:RPD-10 (1:0.01:0.05, w / w / w) ternary mixture is used as a light-emitting layer (where PH86 and P1 are main materials); 25nm of compound ET-61:ET-57 (50 / 50, w / w) mixture is used as an electron transport layer, 1nm of LiF is used as an electron injection layer, and 150nm of metal aluminum is used as a cathode. The total evaporation rate of all organic layers and LiF is controlled at 0.1nm / sec, and the evaporation rate of the metal electrode is controlled at 1nm / sec.

[0121] The differences between Examples 2-26 and Comparative Examples 1-4 and Example 1 are listed in Table 1, and the parts not mentioned in Table 1 are the same as Example 1.

[0122] Performance Testing

[0123] At the same brightness, the external quantum efficiency (EQE, %) of the organic electroluminescent devices prepared in the examples and comparative examples was measured, and the brightness was required to be 3000 cd / m 2 .

[0124] Table 1

[0125]

[0126]

[0127] As can be seen from Table 1, the present invention uses compound I and compound II in organic electroluminescent devices, which can effectively improve the external quantum efficiency, thereby improving the device performance, and ultimately showing excellent characteristics such as reducing device energy consumption and improving brightness. They are electron blocking layer and light-emitting layer materials with good performance, and the external quantum efficiency of the device can reach 19%.

[0128] The only difference between Comparative Example 2 and Example 14 is that the electron blocking layer material is HT5, and its external quantum efficiency is significantly lower than that of Example 14; the only difference between Comparative Example 3 and Example 3 is that the electron blocking layer material is HT5, and its external quantum efficiency is significantly lower than that of Example 3; the only difference between Comparative Example 4 and Example 3 is that the main materials are PH86 and HT-10, and its external quantum efficiency is significantly lower than that of Example 3; the above results prove that the combination of compound I and compound II in the present invention can effectively improve the device efficiency, and replacing any one of them will reduce the efficiency.

[0129] By comparing Example 3 and Example 15, Example 14 and Example 16, it can be seen that when Compound I or Compound II is applied to a dual-host light-emitting layer, the device efficiency can be further improved (Example 3 Example 14), and the effect becomes worse when used alone (Example 15, Example 16).

[0130] By comparing Examples 1-5, 17 and 18, it can be seen that when the mass percentage of the first host material to the second host material is 1%-150% (Examples 1-5), the external quantum efficiency can be further improved. Too low (Example 17) or too high (Example 18) addition will reduce the efficiency.

[0131] By comparing Examples 3, 6-9 with Examples 19 and 20, it can be seen that controlling the thickness of the light-emitting layer to 10-60nm (Examples 3, 6-9) can further improve the external quantum efficiency of the device. Too small thickness (Example 19) or too large thickness (Example 20) will reduce the efficiency.

[0132] By comparing Examples 3, 10-13 and Examples 21, 22, it can be seen that controlling the thickness of the electron blocking layer to 2-100 nm (Examples 3, 10-13) can further improve the external quantum efficiency of the device. Too small thickness (Example 21) or too large thickness (Example 22) will reduce the efficiency.

[0133] The applicant declares that the present invention illustrates the detailed method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed method, that is, it does not mean that the present invention must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises an anode layer, a cathode layer and an organic layer arranged between the anode layer and the cathode layer; the organic layer comprises a light-emitting layer and an electron blocking layer; the thickness of the light-emitting layer is 10-60 nm, and the thickness of the electron blocking layer is 2-100 nm; The light-emitting layer contains a first host material, a second host material and a doping material; The first main material is compound I, and the electron blocking layer contains compound II, or the first main material is compound II, and the electron blocking layer contains compound I; the compound I is The Ar 1 Any one of the following substituted or unsubstituted groups: 9,9-dimethylfluorenyl, 9,9-diphenylfluorenyl, spirofluorenyl, benzo-9,9-dimethylfluorenyl, benzospirofluorenyl; The Ar 2 Any one selected from the following substituted or unsubstituted groups: phenyl, biphenyl, naphthyl; The L 1 One selected from the following substituted or unsubstituted groups: phenylene, biphenylene, naphthylene; The L 2 is selected from a single bond or phenylene; The R 1 , R 2 and R 3 Independently selected from any one of C1-C6 chain alkyl and phenyl; The m is 0; The R 4 Independently selected from any one of substituted or unsubstituted C1-C20 chain alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, and substituted or unsubstituted C6-C30 aryl; The compound II is a compound formed by substituting at least one Rx at any substitutable position on the structure represented by formula (3); The r is 0; The Ar 3 To Ar 4 Each is independently selected from any one of the following substituted or unsubstituted groups: Ar 5 Each is independently selected from any one of the following substituted or unsubstituted groups: The dashed lines represent the connecting bonds of the groups; The L 3 -L 5 Each is independently selected from any one of a single bond and a C6-C20 arylene group; The R 5 Independently selected from any one of substituted or unsubstituted C1-C20 chain alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl; The Rx is selected from any one of the following groups: The wavy lines represent the bonds connecting the groups; Ar 1 To Ar 5 , L 1 , R 4 , R 5 wherein the substituted groups are independently selected from one or a combination of at least two of halogen, C1-C10 chain alkyl, C3-C10 cycloalkyl, C1-C10 alkoxy, C1-C10 thioalkoxy, C6-C30 monocyclic aromatic group, C10-C30 condensed aromatic group, C3-C30 monocyclic heteroaromatic group, and C6-C30 condensed heteroaromatic group; The second main material is 2. The organic electroluminescent device according to claim 1, characterized in that: The compound I has any one of the structures shown below:

3. The organic electroluminescent device according to claim 1, characterized in that: The compound II has any one of the structures shown below:

4. The organic electroluminescent device according to claim 1, characterized in that: The mass percentage of the first main body material to the second main body material is 1%-150%.

5. The organic electroluminescent device according to claim 4, characterized in that: The mass percentage of the first main body material to the second main body material is 10%-100%.

6. The organic electroluminescent device according to claim 1, characterized in that: The thickness of the light-emitting layer is 20-50 nm.

7. The organic electroluminescent device according to claim 1, characterized in that: The thickness of the electron blocking layer is 3-90 nm.

8. The organic electroluminescent device according to claim 1, characterized in that: The organic layer further includes a hole injection layer, a hole transport layer, an electron transport layer and an electron injection layer.

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

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