Electron barrier layer material and blue light organic electroluminescent device

Abstract

The invention provides an electron blocking layer material and a blue light organic electroluminescent device. The electron blocking layer material comprises a compound shown in a formula (I). The compound provided by the invention contains two carbazolyl groups, phenanthryl groups and amido groups which are connected in a specific manner, the HOMO energy level is at a proper level, the interface Gap with a luminescent layer can be reduced, hole injection is facilitated, so that holes and electrons are compounded at higher efficiency, and charge accumulation can be reduced; and moreover, the energy level and carrier balance is better, the voltage rise amplitude is smaller, the efficiency curve is smooth, and the low-gray-scale display effect is facilitated. When the compound provided by the invention is used for an electron blocking layer material of a blue light organic electroluminescent device, the voltage of the device can be reduced, the efficiency is improved, and the service life is prolonged. # imgabs0 #

Description

Technical Field

[0001] This application relates to the technical field of organic light-emitting devices, and particularly to an electron blocking layer material and a blue organic electroluminescent device. Background Art

[0002] With the development of technology, organic electroluminescent devices (OLEDs) have a series of advantages such as being all-solid-state, having a fast response speed, and a wide operating temperature range, and have received increasing attention from the academic and industrial communities. After years of continuous and active exploration, and further optimization of the device structure, process, and related materials, OLEDs have made great progress and have now been industrialized. Although many compounds for OLED electron blocking layer materials have been reported in the past, the prepared OLEDs still have problems such as low efficiency, short lifespan, and poor low gray-scale display effects. Therefore, there is still a need to develop new electron blocking layer materials. Summary of the Invention

[0003] The purpose of this application is to provide a compound that can improve the voltage, efficiency, and lifespan of a blue organic electroluminescent device and has a good low gray-scale display effect when used as an electron blocking layer material. The specific technical solutions are as follows:

[0004] The first aspect of this application provides a compound represented by formula (I):

[0005]

[0006] Wherein,

[0007] L1 and L2 are each independently selected from a single bond, a C6-C 30 arylene or a C5-C 30 heteroarylene;

[0008] Ar1 is selected from

[0009] R8 is each independently selected from deuterium, tritium, a C1-C 39 alkyl, a C3-C 39 cycloalkyl, a C6-C 39 aryl, a C5-C 60 heteroaryl, a C6-C 60 aryloxy, a C1-C 39 alkoxy or a C6-C 39 arylamino; a C1-C 39 alkyl, a C3-C 39 cycloalkyl, a C6-C 39 aryl, a C5-C 60 heteroaryl, a C6-C 60 aryloxy, a C1-C 39The hydrogen in the alkoxy group or C6-C 39 arylamino group is optionally substituted with deuterium; each R8 may be the same or different, and two adjacent R8s may be connected to form a ring;

[0010] p is any integer selected from 0 to 9;

[0011] Ar2 is selected from C6-C 39 aryl, C5-C 60 heteroaryl or C6-C 60 aryloxy;

[0012] At least one of R1-R5 is selected from The remaining groups among R1-R5 are each independently selected from hydrogen, deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino; C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino, and the hydrogen therein is optionally substituted with deuterium; two adjacent groups among R1-R5 may be connected to form a ring;

[0013] L3 is selected from a single bond, C6-C 30 arylene or C5-C 30 heteroarylene;

[0014] R6 and R7 are each independently selected from deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl or C5-C 60 heteroaryl;

[0015] m and n are each independently any integer selected from 0 to 4;

[0016] Each occurrence of the heteroaryl and the heteroarylene independently includes one or more heteroatoms selected from N, O, or S;

[0017] The compound represented by formula (I) includes at least two carbazolyl groups;

[0018] represents the connection site.

[0019] In some embodiments of the present application, in the compound represented by formula (I), L3 is selected from a single bond,

[0020] R9-R 14 、R 15 -R 24 、R 25 -R 32 Any two of them are respectively connected to the connection sites of ; the remaining groups in R9-R 14 、R 15 -R 24 、R 25 -R 32 are each independently selected from hydrogen, deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino; the hydrogen in C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino is optionally substituted by deuterium; any one of R9-R 32 can form a ring with R1-R5 through a single bond, an oxygen bridge or a sulfur bond;

[0021] Preferably, the remaining groups in R9-R 14 、R 15 -R 24 、R 25 -R 32 are each independently selected from hydrogen, deuterium, tritium, C1-C6 alkyl, C3-C6 cycloalkyl, C6-C 18 aryl, C5-C 18 heteroaryl, C6-C 18 aryloxy, C1-C6 alkoxy or C6-C 18 arylamino; any one of R9-R 32 can form a ring with R1-R5 through a single bond, an oxygen bridge or a sulfur bond.

[0022] In some embodiments of the present application, R9-R32 Any one of the rings formed by bonding with R1-R5 through an oxygen bridge or a sulfur bond is selected from:

[0023] In some embodiments of the present application, the relative molecular mass of the compound represented by the formula (I) ≤ 900; preferably, the relative molecular mass of the compound represented by the formula (I) ≤ 850.

[0024] In some embodiments of the present application, the compounds represented by the formula (I) are selected from:

[0025]

[0026] The definitions of L1, L2, Ar2, R8 and p are as defined in the first aspect of the present application.

[0027] In some embodiments of the present application, in the compound represented by the formula (I), L1 and L2 are each independently selected from a single bond or a phenylene group;

[0028] Ar2 is selected from C6-C 18 aryl,

[0029] p is selected from 0.

[0030] In some embodiments of the present application, the HOMO energy level of the compound is -5.06 eV to -5.33 eV, the LUMO energy level of the compound is -1.1 eV to -1.35 eV, and the hole recombination energy of the compound is 0.058 eV to 0.156 eV.

[0031] The second aspect of the present application provides a blue light organic electroluminescent device, which comprises a light emitting layer and an electron blocking layer, and the material used for the electron blocking layer comprises the compound described in the first aspect of the present application; the difference in HOMO energy levels between the host material used for the light emitting layer and the material used for the electron blocking layer is less than 0.5 eV; the LUMO energy level of the material used for the electron blocking layer is shallower than the LUMO energy level of the host material used for the light emitting layer.

[0032] The third aspect of the present application provides a display device, which comprises at least one of the compounds described in the first aspect of the present application or the blue light organic electroluminescent device described in the second aspect of the present application.

[0033] Advantages of the present application:

[0034] The compound provided by this application contains two carbazolyl groups, a phenanthryl group, and an amino group, and the carbazolyl group, phenanthryl group, and amino group are connected in a specific connection manner described in this application. The obtained compound has a HOMO energy level at an appropriate level, which can reduce the interface Gap with the emitting layer (EML), facilitating the injection of holes, thereby enabling the recombination of holes and electrons with higher efficiency and reducing charge accumulation. Moreover, due to the simultaneous presence of phenanthrene and bis-carbazole in the compound of this application, the energy level and carrier balance are better, so the voltage increase amplitude is smaller. Due to the specific connection method of the compound of this application and the synergistic effect of each group in the compound of this application, a smooth efficiency curve can be obtained, which is beneficial to the display effect of low gray levels. By adjusting the HOMO energy level of this application and accordingly adjusting the charge balance, when the obtained compound is used as the electron blocking layer material for a blue organic light-emitting device, the voltage of the device can be reduced, the efficiency can be improved, and the lifespan can be extended.

[0035] Of course, it is not necessary for any product or method implementing this application to simultaneously achieve all the above-mentioned advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of this application, and those of ordinary skill in the art can also obtain other embodiments based on these drawings.

[0037] Figure 1 It is a schematic structural diagram of a blue organic light-emitting device according to an implementation solution of this application; wherein, 10. Substrate, 11. Anode electrode, 12. Hole injection layer, 13. Hole transport layer, 14. Electron blocking layer, 15. Emitting layer, 16. Hole blocking layer, 17. Electron transport layer, 18. Electron injection layer, 19. Cathode electrode;

[0038] Figure 2 It is a voltage-time graph during the lifespan test in Embodiment 2 of this application;

[0039] Figure 3 It is an efficiency-current graph in Embodiment 2 of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The following will clearly and completely describe the technical solutions in this application in combination with the embodiments and drawings of this application. Obviously, the described embodiments are only some embodiments of this application, rather than all embodiments. All other embodiments obtained by those skilled in the art based on this application fall within the scope of protection of this application.

[0041] The first aspect of the present application provides a compound represented by formula (I):

[0042]

[0043] Wherein,

[0044] L1 and L2 are each independently selected from a single bond, C6-C 30 arylene or C5-C 30 heteroarylene;

[0045] Ar1 is selected from

[0046] Each occurrence of R8 is independently selected from deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino; Hydrogen in C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino is optionally substituted by deuterium; Each R8 can be the same or different, and two adjacent R8s can be connected to form a ring;

[0047] p is selected from any integer from 0 to 9;

[0048] Ar2 is selected from C6-C 39 aryl, C5-C 60 heteroaryl or C6-C 60 aryloxy;

[0049] At least one of R1-R5 is selected from The remaining groups among R1-R5 are each independently selected from hydrogen, deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino; C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39Aryl, C5-C 60 Heteroaryl, C6-C 60 Aryloxy, C1-C 39 Alkoxy or C6-C 39 Hydrogen in the arylamino group is optionally substituted by deuterium; two adjacent groups among R1-R5 can be connected to form a ring;

[0050] L3 is selected from a single bond, C6-C 30 Arylene or C5-C 30 Heteroarylene;

[0051] R6 and R7 are each independently selected from deuterium, tritium, C1-C 39 Alkyl, C3-C 39 Cycloalkyl, C6-C 39 Aryl or C5-C 60 Heteroaryl;

[0052] m and n are each independently selected from any integer from 0 to 4;

[0053] Each occurrence of the heteroaryl group and the heteroarylene group independently includes one or more heteroatoms selected from N, O, or S;

[0054] The compound represented by formula (I) includes at least two carbazolyl groups;

[0055] Represents the connection site.

[0056] The "connection site" described in this application represents the connection position with other groups.

[0057] As used in this application means that any hydrogen atom connected to the ring can be substituted by R8, and hydrogen atoms at different sites can be substituted by the same R8 or different R8s, that is, the selection of the specific type of R8 at different sites is independent of each other; p represents the total number of hydrogen atoms substituted, and when p is 0, it means that no hydrogen atom is substituted by R8.

[0058] "At least one of R1-R5 is selected from The remaining groups among R1-R5 are each independently selected from hydrogen, deuterium, tritium, C1-C 39 Alkyl, C3-C 39 Cycloalkyl, C6-C 39 Aryl, C5-C 60 Heteroaryl, C6-C 60 Aryloxy, C1-C 39 Alkoxy or C6-C 39 Arylamino", means that one or more of R1-R5 are selected from The remaining R1-R5 are each independently selected from hydrogen, deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino; for example, R1 and R3 are selected from R2, R4, R5 are each independently selected from hydrogen, deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino.

[0059] In some embodiments of the present application, in the compound of formula (I), L1 and L2 are each independently selected from a single bond, C6-C 18 arylene or C5-C 18 heteroarylene;

[0060] Each occurrence of R8 is independently selected from deuterium, tritium, C1-C6 alkyl, C3-C6 cycloalkyl, C6-C 18 aryl, C5-C 18 heteroaryl, C6-C 18 aryloxy, C1-C6 alkoxy or C6-C 18 arylamino; each R8 can be the same or different, and two adjacent R8s can be linked to form a ring;

[0061] p is selected from any integer from 0 to 2;

[0062] Ar2 is selected from C6-C 18 aryl, C5-C 18 heteroaryl or C6-C 18 aryloxy;

[0063] The remaining groups among R1-R5 are each independently selected from hydrogen, deuterium, tritium, C1-C6 alkyl, C3-C6 cycloalkyl, C6-C 18 aryl, C5-C 18 heteroaryl, C6-C 18 aryloxy, C1-C6 alkoxy or C6-C 18 arylamino; two adjacent groups among R1-R5 can be linked to form a ring;

[0064] L3 is selected from a single bond, C6-C18 Arylene or C5-C 18 heteroarylene;

[0065] R6 and R7 are each independently selected from deuterium, tritium, C1-C6 alkyl, C3-C6 cycloalkyl, C6-C 18 aryl or C5-C 18 heteroaryl;

[0066] m and n are each independently selected from any integer from 0 to 2.

[0067] In some embodiments of the present application, for the compound represented by formula (I), L3 is selected from a single bond,

[0068] R9-R 14 、R 15 -R 24 、R 25 -R 32 Any two of them are respectively connected to the connection sites of ; the remaining groups in R9-R 14 、R 15 -R 24 、R 25 -R 32 are each independently selected from hydrogen, deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino; Hydrogen in C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino is optionally substituted by deuterium; Any one of R9-R 32 can form a ring with R1-R5 through a single bond, an oxygen bridge or a sulfur bond.

[0069] As used in this application, "R9-R 14 、R 15 -R 24 、R 25 -R 32 Any two of them are respectively connected to Connect to the connection site; R9-R 14 、R 15 -R 24 、R 25 -R 32 The remaining groups in are each independently selected from hydrogen, deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino”. It means that one of R9-R 14 is connected to the connection site of , and the other is connected to the connection site of ; The remaining 4 groups in R9-R 14 are each independently selected from hydrogen, deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino; R 15 -R 24 、R 25 -R 32 are defined similarly to R9-R 14 . For example, R9 is connected to the connection site of , R 11 is connected to the connection site of ; R 10 、R 12 、R 13 、R 14 are each independently selected from hydrogen, deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino. As used in this application, "any one of R9-R 32 can form a ring with R1-R5 through a single bond, an oxygen bridge, or a sulfur bond" means that at least one of R1-R5 is selected from R9-R 32Any one of them can form a ring with the remaining groups among R1 - R5 through a single bond, an oxygen bridge or a sulfur bond. For example, R1 is selected from R9 is the connection site with R 11 is the connection site with R 10 R 12 R 13 R 14 Any one of them and any one of R2 - R5 can form a ring through a single bond, an oxygen bridge or a sulfur bond.

[0070] In some embodiments of the present application, in the compound represented by formula (I), the remaining groups among R9 - R 14 R 15 -R 24 R 25 -R 32 are each independently selected from hydrogen, deuterium, tritium, C1 - C6 alkyl, C3 - C6 cycloalkyl, C6 - C 18 aryl, C5 - C 18 heteroaryl, C6 - C 18 aryloxy, C1 - C6 alkoxy or C6 - C 18 arylamino; Any one of R9 - R 32 can form a ring with R1 - R5 through a single bond, an oxygen bridge or a sulfur bond.

[0071] In some embodiments of the present application, the ring formed by any one of R9 - R 32 and R1 - R5 through an oxygen bridge or a sulfur bond is selected from:

[0072] In some embodiments of the present application, the relative molecular mass of the compound represented by formula (I) ≤ 900; preferably, the relative molecular mass of the compound represented by formula (I) ≤ 850.

[0073] In some embodiments of the present application, the compounds represented by formula (I) are selected from:

[0074]

[0075] The definitions of L1, L2, Ar2, R8 and p are as defined in the first aspect of the present application.

[0076] In some embodiments of the present application, in the compound represented by formula (I), L1 and L2 are each independently selected from a single bond or a phenylene group;

[0077] Ar2 is selected from C6 - C 18 aryl,

[0078] p is selected from 0.

[0079] In some embodiments of the present application, the compound represented by formula (I) is selected from the following compounds:

[0080]

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[0117] In some embodiments of the present application, the HOMO energy level of the compound is from -5.06 eV to -5.33 eV, the LUMO energy level of the compound is from -1.1 eV to -1.35 eV, and the hole recombination energy of the compound is from 0.058 eV to 0.156 eV.

[0118] Regarding polycyclic compounds containing heteroatoms, due to the huge differences in properties brought about by the material structure, they are being used in various layers as materials for organic electroluminescent devices. In particular, with the differences in the number of rings, fused positions, types and arrangements of heteroatoms, they have different characteristics such as band gaps (HOMO, LUMO), electrical properties, chemical properties, and physical properties. Therefore, it is necessary to carry out application development for various layers of organic electroluminescent devices, such as the development of electron blocking layer materials.

[0119] The compound provided by this application contains two carbazolyl groups, a phenanthryl group, and an amino group, and the carbazolyl group, phenanthryl group, and amino group are connected in a specific connection manner described in this application. The obtained compound has a HOMO energy level at an appropriate level, which can reduce the interface Gap with the EML and is beneficial to hole injection, so that holes and electrons can recombine with higher efficiency, and charge accumulation can be reduced; and due to the coexistence of phenanthrene and biscarbazole in the compound of this application, the energy level and carrier balance are better, so the voltage increase amplitude is smaller. Due to the specific connection manner of the compound of this application and the synergistic effect of each group in the compound of this application, a smooth efficiency curve can be obtained, which is beneficial to the display effect of low gray levels. By adjusting the HOMO energy level of this application and accordingly adjusting the charge balance, when the obtained compound is used as the electron blocking layer material of a blue organic light-emitting device, the voltage of the device can be reduced, the efficiency can be improved, and the lifespan can be extended.

[0120] The second aspect of this application provides a blue organic light-emitting device, which includes a light-emitting layer and an electron blocking layer, and the material used for the electron blocking layer includes the compound described in the first aspect of this application; the HOMO energy level difference between the host material used for the light-emitting layer and the material used for the electron blocking layer is less than 0.5 eV; the LUMO energy level of the material used for the electron blocking layer is shallower than the LUMO energy level of the host material used for the light-emitting layer.

[0121] Using at least one of the compounds described in the first aspect of this application as the electron blocking layer material can obtain a blue OLED device with a small voltage increase amplitude, high efficiency, and long lifespan.

[0122] In this application, there are no special restrictions on the types and structures of blue organic light-emitting devices, and they can be various types and structures of blue organic light-emitting devices well-known in the art, as long as at least one of the electron blocking layer materials provided by this application can be used. The blue organic light-emitting device includes an anode, a cathode, and one or more light-emitting units may be included between the anode and the cathode; each light-emitting unit includes: (1) a light-emitting layer (EML); (2) a hole transport region, including at least one selected from a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL); and (3) an electron transport region, including an electron transport layer (ETL) and at least one selected from a hole blocking layer (HBL) and an electron injection layer (EIL).

[0123] Specifically, the blue organic light-emitting device of this application may be a top-emitting structure light-emitting device. For example, Figure 1As shown, on the substrate 10, there are successively included a first electrode (anode) 11, a hole injection layer (HIL) 12, a hole transport layer (HTL) 13, an electron blocking layer (EBL) 14, a light-emitting layer (EML) 15, a hole blocking layer (HBL) 16, an electron transport layer (ETL) 17, an electron injection layer (EIL) 18, and a second electrode (cathode) 19.

[0124] The blue light organic electroluminescent device of the present application can be a light-emitting device with a bottom-emitting structure. For example, on the substrate, there are successively included a first electrode (anode), a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a second electrode (cathode).

[0125] The blue light organic electroluminescent device of the present application can also be a light-emitting device with a double-sided emission structure. For example, on the substrate, there are successively included a first electrode (anode), a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a second electrode (cathode).

[0126] The present application has no special limitation on the thickness of each of the above layers, as long as the purpose of the present application can be achieved. For example, the blue light organic electroluminescent device can successively include on the substrate a first electrode (anode) (50 nm to 100 nm) made of metal or metal oxide, a hole injection layer (5 nm to 40 nm), a hole transport layer (30 nm to 130 nm), an electron blocking layer (5 nm to 80 nm), a light-emitting layer (15 nm to 80 nm), a hole blocking layer (5 nm to 20 nm), an electron transport layer (5 nm to 60 nm), an electron injection layer (0.5 nm to 3 nm), and a second electrode (cathode) (10 nm to 200 nm).

[0127] In the organic electroluminescent device of the present application, except that the electron blocking layer contains the electron blocking layer material provided by the present application, various materials used for the layers in the prior art can be used for other layers.

[0128] In the present application, there is no special limitation on the material of the substrate, and conventional substrates known in the art can be selected, such as glass, polymer materials, and glass and polymer materials with thin film transistor (TFT) components, etc.

[0129] In the present application, there is no special limitation on the material of the first electrode (anode electrode), and transparent conductive materials known in the art such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), low temperature polycrystalline silicon (LTPS), etc. can be selected, or metal materials such as silver and its alloys, aluminum and its alloys, etc. can also be selected, or organic conductive materials such as poly(3,4-ethylenedioxythiophene) (PEDOT), etc. can be selected, or multi-layer structures of the above materials, etc.

[0130] In the present application, the material of the hole injection layer (HIL) is not particularly limited, and hole injection materials well-known in the art can be used. For example, the hole injection layer material can be

[0131] In the present application, the material of the hole transport layer (HTL) is not particularly limited and can be selected from hole transport materials known in the art. For example, the hole transport material can be

[0132] In the present application, for the light-emitting layer, it can include a host material and a guest material. The difference in HOMO energy levels between the host material used in the light-emitting layer and the material used in the electron blocking layer is less than 0.5 eV;; the LUMO energy level of the material used in the electron blocking layer is shallower than the LUMO energy level of the host material used in the light-emitting layer;. For example, the host material (BH) can be an anthracene-core compound, such as The guest material (BD) can be a pyrene-core compound (such as ) or a BN compound (such as ). In the present application, the dosages of the host material and the guest material are not particularly limited and can be dosages well-known to those skilled in the art.

[0133] In the present application, the material of the hole blocking layer (HBL) is not particularly limited, and hole blocking layer materials known in the art can be used. For example, the hole blocking material can be

[0134] In the present application, the material of the electron transport layer (ETL) is not particularly limited, and electron transport materials known in the art can be used. For example, the electron transport material can be

[0135] In the present application, the material of the electron injection layer (EIL) is not particularly limited, and electron injection materials well-known in the art can be used. For example, the electron injection material can be (Liq).

[0136] In the present application, the material of the second electrode (reflective cathode electrode) is not particularly limited, and electron injection materials well-known in the art can be used. For example, the second electrode (reflective cathode electrode) material can be selected from at least one of materials such as Al, Mg, Ag, Mg:Ag, etc.

[0137] The present application has no particular limitation on the preparation method of the blue light organic electroluminescent device, and any method well-known in the art can be adopted. For example, it can include but is not limited to the following steps:

[0138] (1) Clean the substrate coated with the first electrode (anode electrode) by a combination of one or more methods such as chemical washing, water washing, brushing, high-pressure water washing, air knife, UV irradiation, nitrogen treatment, oxygen treatment, etc., and then perform heat treatment;

[0139] (2) Vacuum deposit a hole injection material on the first electrode (anode electrode) as a hole injection layer;

[0140] (3) Vacuum deposit a hole transporting material on the hole injection layer as a hole transporting layer;

[0141] (4) Vacuum deposit an electron blocking material on the hole transporting layer as an electron blocking layer;

[0142] (5) Vacuum deposit a blue light emitting layer on the electron blocking layer, and the blue light emitting layer contains a host material and a guest material;

[0143] (6) Vacuum deposit a hole blocking material on the light emitting layer as a hole blocking layer;

[0144] (7) Vacuum deposit an electron transporting material on the hole blocking layer as an electron transporting layer;

[0145] (8) Vacuum deposit an electron injection material on the electron transporting layer as an electron injection layer;

[0146] (9) Vacuum deposit a cathode material on the electron injection layer as the second electrode (reflective cathode electrode).

[0147] The fourth aspect of the present application provides a display device, which includes at least one of the compounds described in the first aspect of the present application, the electron blocking layer material described in the second aspect of the present application, or the blue light organic electroluminescent device described in the third aspect of the present application.

[0148] The display device described in the present application includes, but is not limited to, a display, a television, a tablet computer, a mobile communication terminal, etc.

[0149] Hereinafter, examples and comparative examples are given to more specifically illustrate the embodiments of the present application. Various tests and evaluations are carried out according to the following methods. In addition, unless otherwise specified, "parts" and "%" are based on mass.

[0150] The specific compounds provided by the present application can all be further reacted with the halides, especially the bromides (C) formed in this way, by methods familiar to those skilled in the art, such as C-C coupling (such as Suzuki, Negishi, Yamamoto, Grignard Cross, Stille, Heck coupling, etc.) or C-N coupling (such as Buchwald or Ullmann coupling, silylation, phosphidation, boration, polycondensation, etc.).

[0151] The reaction general formula is as follows:

[0152]

[0153] A specific synthesis method is given below, and the specific synthesis route is not limited to this.

[0154] Synthesis Example 1: Synthesis of Compound 1

[0155]

[0156] Dissolve 3-phenanthrylamine (Ⅰ-1) (4.06, 21 mmol) and 4-bromobiphenyl (Ⅱ-1) (4.66 g, 20 mmol) in toluene solvent, stir under nitrogen protection until reflux, and then successively add sodium tert-butoxide, Sphos (2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl), and Pd2(dba)3, and heat to reflux for overnight reaction. After the reaction is completed, cool to room temperature, then add distilled water to the reaction solution and extract the reaction solution with an organic solvent dichloromethane (DCM). Then dry the extracted organic layer with magnesium sulfate and remove the solvent using a rotary evaporator. Purify the remaining substance by column chromatography and remove the solvent using a rotary evaporator. Recrystallize the solid with toluene / n-heptane to obtain Intermediate Ⅲ-1 (purity: 98.7%, yield: 82%, MS[M+H]+: 345.92; C 26 H 19 N).

[0157]

[0158] Dissolve Intermediate Ⅲ-1 (7.25 g, 21 mmol) and raw material Ⅳ-1 (9.74 g, 20 mmol, CAS: 750573-24-1) in toluene solvent, stir under nitrogen protection until reflux, and then successively add sodium tert-butoxide, Sphos, and Pd2(dba)3, and heat to reflux for overnight reaction. After the reaction is completed, cool to room temperature, then add distilled water to the reaction solution and extract the reaction solution with an organic solvent dichloromethane (DCM). Then dry the extracted organic layer with magnesium sulfate and remove the solvent using a rotary evaporator. Purify the remaining substance by column chromatography and remove the solvent using a rotary evaporator. Recrystallize the solid with toluene / n-heptane to obtain the product, namely Compound 1 (12.92 g, purity: 99.48%, yield: 86%, MS[M+H]+: 752.87; C 56 H 37 N3).

[0159] Referring to the synthesis process of Synthesis Example 1, the reactants, products, yields, purities, and mass spectrometry data in the synthesis processes of Compounds 2-15 and 34 are shown in Synthesis Examples 2-16 respectively.

[0160] Synthesis of Intermediate VII-9

[0161]

[0162] Under nitrogen protection, 4-bromophenylboronic acid pinacol ester (V-9) (5.66 g, 20 mmol), IV-1 (10.2 g, 21 mmol) and potassium carbonate (6.0 g) were added to a dry three-necked flask. 100 mL of toluene, 35 mL of ethanol and 35 mL of deionized water were added. The mixture was heated and stirred until dissolved, then triphenylphosphine palladium (0.35 g, 0.3 mmol) was added, and the mixture was heated to reflux. The reaction was monitored by TLC. After the reaction was completed, the mixture was washed with water, extracted with dichloromethane, and the solvent was removed by a rotary evaporator. Then, the residue was purified by silica gel column chromatography using n-heptane and dichloromethane (10:1), and the solvent was removed by a rotary evaporator. The resulting pale yellow solid was recrystallized, filtered by suction, and dried under vacuum to obtain Intermediate VII-9 (7.44 g, yield: 66%, purity 96.5%; MS [M+H]+: 564.56).

[0163] Synthesis Example 2: Synthesis of Compound 2

[0164]

[0165] Yield of Compound 2: 65.5%; Purity: 98.7%; MS [M+H]+: 627.59

[0166] Synthesis Example 3: Synthesis of Compound 3

[0167]

[0168] Yield of Compound 3: 64.8%; Purity: 98.6%; MS [M+H]+: 752.45

[0169] Synthesis Example 4: Synthesis of Compound 4

[0170]

[0171] Yield of Compound 4: 66.7%; Purity: 98.1%; MS [M+H]+: 752.49

[0172] Synthesis Example 5: Synthesis of Compound 5

[0173]

[0174] Yield of Compound 5: 63.9%; Purity: 98.2%; MS [M+H]+: 766.63

[0175] Synthesis Example 6: Synthesis of Compound 6

[0176]

[0177] Yield of Compound 6: 65.85%; Purity: 98.2%; MS[M+H]+: 766.58.

[0178] Synthesis Example 7: Synthesis of Compound 7

[0179]

[0180] Yield of Compound 7: 66.7%; Purity: 98.6%; MS[M+H]+: 766.38.

[0181] Synthesis Example 8: Synthesis of Compound 8

[0182]

[0183] Yield of Compound 8: 66.2%; Purity: 99.4%; MS[M+H]+: 766.28.

[0184] Synthesis Example 9: Synthesis of Compound 9

[0185]

[0186] Yield of Compound 9: 61.1%; Purity: 99.0%; MS[M+H]+: 752.38. Synthesis Example 10: Synthesis of Compound 10

[0187]

[0188] Yield of Compound 10: 60.7%; Purity: 99.1%; MS[M+H]+: 829.5. Synthesis Example 11: Synthesis of Compound 11

[0189]

[0190] Yield of Compound 11: 60.4%; Purity: 99.7%; MS[M+H]+: 829.38.

[0191] Synthesis Example 12: Synthesis of Compound 12

[0192]

[0193] Yield of Compound 12: 60.7%; Purity: 99.6%; MS[M+H]+: 829.4. Synthesis Example 13: Synthesis of Compound 13

[0194]

[0195] Yield of Compound 13: 59.7%; Purity: 99.6%; MS[M+H]+: 829.3. Synthesis Example 14: Synthesis of Compound 14

[0196]

[0197] Yield of Compound 14: 59.5%; Purity: 99.5%; MS[M+H]+: 829.6. Synthesis Example 15: Synthesis of Compound 15

[0198]

[0199] Yield of Compound 15: 61.9%; Purity: 99.8%; MS[M+H]+: 829.9.

[0200] Synthesis Example 16: Synthesis of Compound 34

[0201]

[0202] Yield of Compound 34: 60.7%; Purity: 99.7%; MS[M+H]+: 829.7.

[0203] For other compounds of this application, appropriate raw materials can be selected for synthesis according to the ideas of the above Synthesis Examples 1-16, or any other appropriate methods and raw materials can be selected for synthesis.

[0204] Example 1

[0205] In this example, the HOMO energy level, LUMO energy level, Eg, and hole recombination energy (ROE) of different compounds of this application and 4 comparative compounds were measured. The specific measurement methods are as follows.

[0206] 1. Measurement of HOMO energy level, LUMO energy level, and Eg

[0207] In this application, a photoelectron spectrophotometer AC3 was used to measure the HOMO energy level and LUMO energy level. By irradiating the sample with ultraviolet light and measuring the kinetic energy of secondary electrons at the low-energy end, the position of the HOMO energy level of the material was determined. Specifically, when ultraviolet light with a specific wavelength of energy irradiates the sample, part of the energy is used to overcome the electron binding energy, and the remaining part enables the electrons to obtain kinetic energy. By analyzing the positions of these physical parameters in the spectrum, the HOMO energy level of the material can be obtained. Measure the absorption spectrum of the test material, the intersection of the absorption spectrum rising tangent and the abscissa, divide 1240 by the intersection point to obtain Eg, and LUMO = HOMO - Eg.

[0208] 2. Measurement of hole recombination energy (ROE)

[0209] This application relies on quantum chemical calculation methods, especially density functional theory (DFT) methods, to explore the electron transfer process and measure the hole recombination energy.

[0210] The structures of Compounds 1-15 in the measured compounds are as shown in Synthesis Examples 1-15, and the structures of D1-D4 and Compounds 16-33 are as follows:

[0211]

[0212]

[0213] The measured results are shown in Table 1.

[0214] Table 1

[0215] Compound ROE (eV) LUMO (eV) HOMO (eV) Eg (eV) D1 0.092 -1.13 -5.06 3.93 D2 0.157 -1.21 -5.22 4.01 D3 0.107 -1.17 -5.06 3.89 D4 0.128 -1.45 -5.32 3.87 Compound 1 0.119 -1.2 -5.19 3.99 Compound 2 0.098 -1.25 -5.18 3.93 Compound 3 0.097 -1.21 -5.25 4.04 Compound 4 0.156 -1.28 -5.23 3.95 Compound 5 0.131 -1.32 -5.33 4.01 Compound 6 0.139 -1.15 -5.16 4.01 Compound 7 0.141 -1.18 -5.17 3.99 Compound 8 0.136 -1.12 -5.2 4.08 Compound 9 0.155 -1.19 -5.18 3.99 Compound 10 0.147 -1.22 -5.24 4.02 Compound 11 0.100 -1.3 -5.13 3.83 Compound 12 0.076 -1.17 -5.16 3.99 Compound 13 0.067 -1.28 -5.07 3.79 Compound 14 0.082 -1.34 -5.12 3.72 Compound 15 0.079 -1.23 -5.14 3.91 Compound 16 0.071 -1.27 -5.17 3.90 Compound 17 0.107 -1.28 -5.1 3.58 Compound 18 0.109 -1.26 -5.11 3.65 Compound 19 0.097 -1.26 -5.12 3.66 Compound 20 0.067 -1.31 -5.26 3.95 Compound 21 0.082 -1.3 -5.23 3.93 Compound 22 0.075 -1.31 -5.24 3.93 Compound 23 0.089 -1.25 -5.25 4.00 Compound 24 0.095 -1.31 -5.22 3.91 Compound 25 0.096 -1.28 -5.31 4.03 Compound 26 0.085 -1.32 -5.23 3.91 Compound 27 0.074 -1.24 -5.1 3.86 Compound 28 0.096 -1.1 -5.11 4.01 Compound 29 0.063 -1.18 -5.11 3.93 Compound 30 0.069 -1.26 -5.18 3.92 Compound 31 0.058 -1.31 -5.16 3.85 Compound 32 0.076 -1.35 -5.26 3.91 Compound 33 0.084 -1.3 -5.31 4.01

[0216] Example 2

[0217] The ITO substrate was cleaned and dried; the HIL material, HTL material, and EBL material were sequentially evaporated on the anode; then the light-emitting layers BH and BD were evaporated; the HBL material, ETL material, and EIL material were evaporated on the light-emitting layer; then the cathode was evaporated to obtain a blue organic electroluminescent device.

[0218] The structure of the blue organic electroluminescent device is as follows: the material of the first electrode is ITO; the thickness of the HIL is 10 nm; the thickness of the HTL is 110 nm; the thickness of the EBL is 75 nm; the EML is composed of BH and BD, and the thickness of the evaporated film layer of BD accounts for 2% of the total thickness of the light-emitting layer, and the thickness of the EML is 45 nm; the thickness of the HBL is 5 nm; the thickness of the ETL is 30 nm; the thickness of the EIL is 1 nm; the material of the second electrode is Mg and Ag, and the thickness of the second electrode is 13 nm.

[0219] In all blue organic electroluminescent devices, the material of the hole injection layer (HIL) is PD, the material of the hole transport layer (HTL) is HT-1, and the material of the electron injection layer (EIL) is Liq. The specific structures are as follows. The host material (BH), guest material (BD), hole blocking layer (HBL) material, and electron transport layer (ETL) material used in the light-emitting layer are shown in the following structural formulas.

[0220]

[0221] The HOMO energy level and LUMO energy level of the host material (BH) used in the above light-emitting layer were measured by the measurement methods of the HOMO energy level and LUMO energy level in Example 1, and the results are shown in Table 2 below.

[0222] Table 2

[0223] Compound LUMO (eV) HOMO (eV) BH -2.72 -5.42

[0224] The electron blocking layer (EBL) materials selected for the devices in different groups are Compound 1, 8, 12, 17, 21, 23, 27, 29, 33 of the present application and control compounds D1, D2, D3, D4, and their structural formulas are as shown in Example 1. The devices in different groups are the same except for the different electron blocking layer materials used.

[0225] The prepared blue organic light-emitting devices were subjected to performance measurement. The measurement method was as follows: at the same brightness, use a digital source meter and a luminance meter to measure the driving voltage (V), blue light efficiency (BI), and device lifetime (LT95) of the blue organic light-emitting devices in different groups. Specifically, measure the voltage corresponding to a current density of 15 mA / cm 2 at this time, which is the driving voltage V, and the corresponding efficiency is the current efficiency, expressed as the blue light efficiency (BI) by dividing the current efficiency by the chromaticity coordinate CIEy; the lifetime test of LT95 is as follows: use a luminance meter to keep a constant current at a brightness of 1000 nit, and measure the time when the brightness of the blue organic light-emitting device drops to 950 nit, with the unit of hours.

[0226] The measurement results were calculated based on the results of Control Group 1 as 100%, and the relative results of the blue organic light-emitting devices in other groups were calculated. The specific results are shown in Table 3.

[0227] Table 3

[0228] Device Electron blocking layer material V(％) BI (%) LT95 (%) Experimental group 1 Compound 1 98.5 112.5 153.5 Experimental group 2 Compound 8 98.5 115.5 143.5 Experimental group 3 Compound 12 98.7 117.4 123.5 Experimental group 4 Compound 17 98.4 114.7 130.7 Experimental group 5 Compound 21 97.9 124.1 132.3 Experimental group 6 Compound 23 97.5 119.7 138.6 Experimental group 7 Compound 27 97.3 112.1 123.3 Experimental group 8 Compound 29 97.3 109.5 138.5 Experimental group 9 Compound 33 99.5 106.8 138.6 Control group 1 D1 100 100 100 Control group 2 D2 99.5 99.5 105.8 Control group 3 D3 112.7 96.5 95.9 Control group 4 D4 99.8 97.1 93.7

[0229] It can be seen from the results in Table 3 that the compounds provided in the present application, when used as electron blocking layer materials in blue organic light-emitting devices, have the effects of reducing voltage, improving efficiency, and extending lifetime. Combining with Table 1, it can be known that the compound D4 in Control Group 4 has a relatively deep LUMO, weak blocking of excitons and polarons, so it is easily attacked and has a short lifetime. And due to a small amount of exciton leakage, the efficiency is also low.

[0230] The inventors of the present application believe that: the L3 of Compound 1 and Compound 8 is a direct bond, and the two carbazole groups are respectively located at the meta positions of the phenyl group, with smaller steric hindrance of the material and a more stable spatial configuration. Therefore, it is less likely to change when contacting excitons, polarons, electrons, etc., and has the highest lifetime. For Compound 12 and Compound 27, L3 is a phenyl group, forming a biphenyl group with a slightly longer conjugated chain. Therefore, the molecular deformability is larger than that of Compound 1 and 2, and the lifetime is relatively slightly shorter, but still has excellent effects compared with Compound D1; further, after bridging the biphenyl group with oxygen (Compound 17 and Compound 33), the deformability is reduced, and thus the lifetime is improved.

[0231] Figure 2 This is the voltage-time graph during the lifetime test in Example 2 of the present application. It can be seen from Figure 2 that for Experimental Groups 1-9 of the present application, the voltage increase amplitude is smaller than that of Control Groups 2-4. During the lifetime test of the present application, it was found that when the compound provided by the present application is used in a blue organic electroluminescent device, due to the simultaneous presence of phenanthrene and bis-carbazole, the energy levels and carrier balance are better, so the voltage increase amplitude is smaller.

[0232] Figure 3 This is the efficiency-current graph in Example 2 of the present application. It can be seen from Figure 3 that for Experimental Groups 1, 3, and 6 of the present application, the efficiency curves are smoother than that of Control Group 1. Compared with Control Group 1 (D1), due to the specific connection mode of the compound provided by the present application and the synergistic effect of each group in the compound of the present application, a smooth efficiency curve can be obtained, which is beneficial to the display effect of low gray levels. Without being limited to any theory, the inventors of the present application believe that: perhaps when L3 is a direct bond or L3 is a phenyl group, the two carbazole groups are respectively located at the two meta-positions of L3 (phenyl group), the conjugated chain is shorter, and it has a higher T1, so the display effect of low gray levels can be achieved.

[0233] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the scope of protection of the present application.

Claims

1. A compound represented by formula (I): Wherein, L1 and L2 are each independently selected from a single bond, C6-C 30 arylene or C5-C 30 heteroarylene; Ar1 is selected from R8, each occurrence independently, is selected from deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino; the hydrogen in C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino is optionally substituted by deuterium; each R8 can be the same or different, and two adjacent R8s can be linked to form a ring; p is any integer selected from 0 - 9; Ar2 is selected from C6-C 39 aryl, C5-C 60 heteroaryl or C6-C 60 aryloxy; At least one of R1-R5 is selected from The remaining groups among R1-R5 are each independently selected from hydrogen, deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino; the hydrogen in C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino is optionally substituted by deuterium; two adjacent groups among R1-R5 may be linked to form a ring; L3 is selected from a single bond, a C6-C 30 arylene or a C5-C 30 heteroarylene; R6 and R7 are each independently selected from deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl or C5-C 60 heteroaryl; m and n are each independently any integer selected from 0 - 4; Each occurrence of the heteroaryl and the heteroarylene independently includes one or more heteroatoms selected from N, O, or S; The compound represented by formula (I) includes at least two carbazolyl groups; Indicates a connection site.

2. The compound according to claim 1, wherein, L3 is selected from a single bond, R9-R 14 、R 15 -R 24 、R 25 -R 32 Any two of them are respectively connected to the connection sites of ; R9-R 14 、R 15 -R 24 、R 25 -R 32 The remaining groups in are each independently selected from hydrogen, deuterium, tritium, C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino; The hydrogen in C1-C 39 alkyl, C3-C 39 cycloalkyl, C6-C 39 aryl, C5-C 60 heteroaryl, C6-C 60 aryloxy, C1-C 39 alkoxy or C6-C 39 arylamino is optionally substituted by deuterium; Any one of R9-R 32 can form a ring with R1-R5 through a single bond, an oxygen bridge or a sulfur bond.

3. The compound according to claim 2, wherein, R9-R 32 Any one of which forms a ring with R1-R5 through an oxygen bridge or a sulfur bond and is selected from:

4. The compound according to claim 1, wherein, The relative molecular mass of the compound represented by formula (I) ≤ 900.

5. The compound according to any one of claims 1-4, wherein The compound is selected from: The definitions of L1, L2, Ar2, R8, and p are as defined in any one of claims 1 - 4.

6. The compound according to claim 5, wherein, L1 and L2 are each independently selected from a single bond or a phenylene group; Ar2 is selected from C6-C 18 aryl, p is selected from 0.

7. The compound according to claim 1, wherein, The compound is selected from the following compounds:

8. The compound according to claim 1, wherein The HOMO energy level of the compound is -5.06 eV to -5.33 eV, the LUMO energy level of the compound is -1.1 eV to -1.35 eV, and the hole recombination energy of the compound is 0.058 eV to 0.156 eV.

9. A blue light organic electroluminescent device, which comprises a light emitting layer and an electron blocking layer, and the material used for the electron blocking layer comprises the compound according to any one of claims 1 - 8; the difference in HOMO energy levels between the host material used for the light emitting layer and the material used for the electron blocking layer is less than 0.5 eV; the LUMO energy level of the material used for the electron blocking layer is shallower than the LUMO energy level of the host material used for the light emitting layer.

10. A display device, which comprises at least one of the compounds according to any one of claims 1 - 8 or the blue light organic electroluminescent device according to claim 9.

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