Benzimidazole derivative and organic electroluminescent element containing same

Abstract

The invention belongs to the technical field of photoelectric materials, and particularly relates to a benzimidazole derivative and an organic electroluminescent element containing the same. The benzimidazole derivative has a structure # imgabs0 # as shown in a formula (1), wherein at least one of L1 and L2 is selected from substituted or unsubstituted N-containing heteroarylene with the ring atom number of 6-30, the other one which is not the N-containing heteroarylene is selected from a single bond, substituted or unsubstituted arylene with the ring atom number of 6-30 and substituted or unsubstituted heteroarylene with the ring atom number of 5-30, and the other one is selected from a single bond, substituted or unsubstituted arylene with the ring atom number of 6-30 and substituted or unsubstituted heteroarylene with the ring atom number of 5-30. Ar1 and Ar2 are respectively and independently selected from hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted aryl with the ring atom number of 6-30, and substituted or unsubstituted heteroaryl with the ring atom number of 5-30.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic materials, and particularly relates to a benzimidazole derivative and an organic electroluminescent device comprising the same. Background Art

[0002] OLED emits light by the cancellation of hole-electron pairs generated when holes and electrons are injected from a hole injection electrode (anode) and an electron injection electrode (cathode) into a light-emitting material layer (EML) disposed between the anode and the cathode. Such an OLED can be formed on a flexible transparent substrate such as plastic, can also operate at a low voltage (below 10 V), consumes relatively low power, and provides excellent colors.

[0003] Generally, OLEDs can be divided into single-stack type and stacked type. To achieve a long-life OLED, tandem OLEDs are mainly used, that is, OLEDs having a structure in which a plurality of light-emitting units are stacked. For example, a tandem white OLED includes a first light-emitting stack including a blue light-emitting layer and a second light-emitting stack including a yellow-green light-emitting layer, wherein the first light-emitting stack and the second light-emitting stack are vertically stacked. Such a white OLED emits white light by mixing the light emitted from the blue light-emitting layer and the light emitted from the yellow-green light-emitting layer. The stacked OLED includes a charge generation layer disposed between the first light-emitting stack and the second light-emitting stack to improve the current efficiency in each light-emitting layer while ensuring that charges are effectively distributed to the light-emitting stacks. Generally, the charge generation layer has a PN junction, in which an N-type charge generation layer and a P-type charge generation layer are sequentially stacked.

[0004] In such a charge generation layer for a common tandem OLED, due to the energy level difference between the N-type charge generation layer and the P-type charge generation layer, charges are generated at the interface between the P-type charge generation layer and the adjacent hole injection layer or hole transport layer, resulting in deterioration of electron injection in the N-type charge generation layer.

[0005] When the N-type charge generation layer is doped with a metal, the metal may diffuse into the P-type charge generation layer, resulting in a reduction in the life of the OLED. In particular, common materials for the charge generation layer do not have sufficient thermal / electrical stability. Therefore, the long-term operation of the OLED causes degradation or deterioration of the materials for the charge generation layer. As a result, not only the electron injection efficiency from the interface between the P-type charge generation layer and the adjacent hole injection layer or hole transport layer to the N-type charge generation layer is significantly reduced, but also the electron injection efficiency from the N-type charge generation layer to the adjacent electron transport layer is significantly reduced, resulting in a reduction in the performance and life of the OLED.

[0006] Therefore, there is a need for a compound such that an organic electroluminescent device prepared from the compound can have a long service life and good current efficiency. Summary of the Invention

[0007] The object of the present invention is a benzimidazole derivative, and an organic electroluminescent device prepared using the benzimidazole derivative can achieve a durable service life and good current efficiency.

[0008] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0009] A benzimidazole derivative, the compound having the structure shown in formula (1) Wherein

[0010] L 1 and L 2 At least one of them is selected from a substituted or unsubstituted N-containing heteroaryl group having 6 to 30 ring atoms, and the other one that is not an N-containing heteroaryl group is selected from a single bond, a substituted or unsubstituted arylene group having 6 to 30 ring atoms, and a substituted or unsubstituted heteroarylene group having 5 to 30 ring atoms.

[0011] Ar 1 and Ar 2 Each independently is selected from hydrogen, deuterium, halogen, cyano, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C3-C10 cycloalkyl group, a substituted or unsubstituted aryl group having 6 to 30 ring atoms, and a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms.

[0012] When the substituents in the "substituted or unsubstituted" are substituted, the substituents are each independently selected from one or a combination of deuterium, halogen, cyano, a C1-C10 alkyl group, a C3-C10 cycloalkyl group, a C6-C30 aryl group, and a C3-C30 heteroaryl group.

[0013] The heteroatoms of the heteroaryl group are selected from one or more of oxygen, sulfur, and nitrogen.

[0014] Preferably, the N in the N-containing heteroaryl group having 6 to 30 ring atoms is at least 2, and no other heteroatoms are contained.

[0015] Preferably, the N-containing heteroaryl group having 6 to 30 ring atoms is selected from a pyrimidinylene group, a pyrazinylene group, a quinoxalinylene group, a quinazolinylene group, a phenanthrolinylene group, a pyridinopyridinylene group, and a pyridinopyridoisoquinolylene group;

[0016] More preferably, the N-containing heteroaryl group having 6 to 30 ring atoms is selected from a phenanthrolinylene group.

[0017] L 1 and L 2Another group that is not a nitrogen-containing heteroaryl group is selected from a single bond and a substituted or unsubstituted group such as: phenylene, naphthylene, phenanthrylene, anthrylene, triphenylene, fluoranthenylene, pyrenylene, dibenzofuranylene, dibenzothiophenylene, benzofuranylene, benzothiophenylene, furanylene, thiophenylene.

[0018] Preferably, Ar 1 and Ar 2 are each independently selected from hydrogen, deuterium, halogen, and a substituted or unsubstituted group such as: phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthryl, triphenyl, fluoranthenyl, pyrenyl, perylenyl, fluorenyl, 9,9'-dimethylfluorenyl, 9,9'-diphenylfluorenyl, furanyl, benzofuranyl, thiophenyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, pyridyl, bipyridyl, terpyridyl, pyrimidinyl, pyrazinyl, quinolinyl, isoquinolinyl, quinoxalinyl, quinazolinyl, phenanthrolinyl, indolopyridinyl, indolopyrimidinyl, carbazolyl, phthalazinyl.

[0019] Preferably, when the "substituted or unsubstituted" is substituted, the substituents are each independently selected from deuterium, halogen, cyano, methyl, ethyl, tert-butyl, cyclohexyl, phenyl, biphenyl, terphenyl, naphthyl, anthryl, phenanthryl, pyrenyl, fluoranthenyl, triphenyl, group, dibenzofuranyl, dibenzothiophenyl, or a combination of one or more thereof.

[0020] Application of the benzimidazole derivative described in the present invention as a material for an organic electroluminescent element.

[0021] The present invention provides an organic electroluminescent element, comprising an anode, a cathode, and an organic layer between the anode and the cathode, wherein the organic layer contains the benzimidazole derivative described in the present invention.

[0022] Preferably, the organic layer includes an electron transport layer and a light-emitting layer, and the electron transport layer contains the benzimidazole derivative described in the present invention.

[0023] Preferably, the organic layer contains at least two light-emitting units, a charge generation layer is included between the light-emitting units, the light-emitting units include an electron transport layer, and at least one of the at least one charge generation layer or / and at least one electron transport layer contains the benzimidazole derivative described in the present invention.

[0024] Preferably, the organic layer contains two or more light-emitting units, a charge generation layer is included between the light-emitting units, the light-emitting units include an electron transport layer, the charge generation layer includes an N-type charge generation layer and a P-type charge generation layer, and at least one of the N-type charge generation layer and the electron transport layer contains the benzimidazole derivative described in the present invention.

[0025] The electron transport layer includes the electron transport layers of respective light-emitting units. At least one of the N-type charge generation layer and the electron transport layer containing the benzimidazole derivative described in the present invention means including an N-type charge generation layer containing the benzimidazole derivative described in the present invention; or multiple N-type charge generation layers containing the benzimidazole derivative described in the present invention; or an electron transport layer in one light-emitting unit containing the benzimidazole derivative described in the present invention; or an N-type charge generation layer and an electron transport layer in one light-emitting unit containing the benzimidazole derivative described in the present invention; or an N-type charge generation layer and the electron transport layers of multiple light-emitting units each containing the benzimidazole derivative described in the present invention; or multiple N-type charge generation layers and the electron transport layers of multiple light-emitting units each containing the benzimidazole derivative described in the present invention, etc. When two or more layers contain the benzimidazole derivative of the present invention, the benzimidazole derivatives may be the same or different.

[0026] The stacked structure described in the present invention refers to n light-emitting units, where n is greater than or equal to 2, and the number of N-type charge generation layers is n - 1.

[0027] An electronic device includes the organic electroluminescent element described in the present invention.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: The compound described in the present invention has a structure in which benzimidazole is connected to another N-containing heteroaryl group. When used in the N-type charge generation layer, the nitrogen atom of the organic compound combines or bonds with an alkali metal or alkaline earth metal used as a dopant in the N-type charge generation layer to form an energy gap state, and thus the electron transport characteristics from the N-type charge generation layer to the electron transport layer are improved. The compound of the present invention improves the injection and transport ability of electrons, and the organic electroluminescent element prepared using this compound can achieve high current efficiency and a durable service life. Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of the organic electroluminescent element described in Application Example 1, where the first electrode layer 1, hole injection layer 2, hole transport layer 3, light-emitting layer 4, electron transport layer 5, N-type charge generation layer 6, P-type charge generation layer 7, hole transport layer 8, light-emitting layer 9, electron transport layer 10, electron injection layer 11, and second electrode layer 12, where 100 is the first light-emitting unit and 200 is the second light-emitting unit. Detailed Embodiments

[0030] The technical solutions of the present invention will be further specifically described below through specific embodiments. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any formal modification and / or change made to the present invention will fall within the protection scope of the present invention.

[0031] In the present invention, unless otherwise specified, all parts and percentages are by weight, and the equipment and raw materials used can be obtained from the market or are commonly used in the art. The methods in the following examples are conventional methods in the art unless otherwise specified.

[0032] Unless otherwise specified, the reagents used in the following examples can be purchased from a conventional biochemical reagent store.

[0033] As used in the present invention, the term "halogen" may include fluorine, chlorine, bromine or iodine.

[0034] As used in the present invention, the term "C1-C10 alkyl" refers to a monovalent substituent derived from a straight-chain or branched-chain saturated hydrocarbon having 1 to 10 carbon atoms, and examples thereof include, but are not limited to, methyl, ethyl, propyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl and hexyl.

[0035] As used in the present invention, the term "C3-C10 cycloalkyl" refers to a monovalent substituent derived from a monocyclic or polycyclic non-aromatic hydrocarbon having 3 to 10 carbon atoms. Examples of such cycloalkyls include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, norbornyl, adamantyl, etc.

[0036] As used in the present invention, the term "C2-C10 heterocycloalkyl" has a monovalent substituent of a monocyclic or polycyclic having 2 to 10 carbon atoms, and at least one heteroatom is included in the ring, and the heteroatom is selected from O, S, N, P, Si.

[0037] As used in the present invention, the term "alkoxy" refers to a straight-chain, branched-chain or cyclic chain. The number of carbon atoms of the alkoxy is not particularly limited herein, but the alkoxy preferably has 1 to 10 carbon atoms. Specific examples thereof include, but are not limited to, methoxy, ethoxy, n-propoxy, isopropoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, sec-butoxy, n-pentyloxy, neopentyloxy, isopentyloxy, n-hexyloxy, benzyloxy.

[0038] As used in the present invention, the term "C6-C60 aryl" refers to a monovalent substituent derived from an aromatic hydrocarbon having a single ring or a combination of two or more rings and having 6 to 60 carbon atoms. Further, such an aryl may have a form in which two or more of the rings are simply side-bonded to each other or fused to each other. Examples of such aryls include, but are not limited to, phenyl, biphenyl, naphthyl, phenanthryl, anthryl, pyrenyl, triphenylenyl, fluoranthenyl, dimethyl 9,9-dimethylfluorene, 9,9-diphenylfluorene, spirobifluorene, etc.

[0039] As used in the present invention, the term "arylene" refers to a divalent aryl derived by removing one hydrogen atom from "aryl", for example, phenyl removing one hydrogen atom forms phenylene, and naphthyl removing one hydrogen atom forms naphthylene.

[0040] As used in the present invention, the term "heteroaryl having 3 to 60 carbon atoms" refers to a monovalent substituent derived from a monocyclic or polycyclic aromatic hydrocarbon having 3 to 60 carbon atoms. In this connection, at least one carbon, preferably 1 to 3 carbons in the ring, is replaced by a heteroatom such as N, O, S, P, B or Si. In addition, such heteroaryl may have a form in which two or more rings are simply side-bonded to each other or fused to each other or fused to an aryl group. Examples of such heteroaryl include pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazinyl, indolizinyl, indolyl, indolopyridyl, purinyl, phenanthrolinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, thiazolyl, imidazolyl, oxazolyl, furyl, thienyl, benzofuryl, benzothienyl, benzothiazolyl, benzimidazolyl, benzoxazolyl, carbazolyl, dibenzofuryl, dibenzothienyl, etc., and the present invention is not limited thereto.

[0041] As used in the present invention, the term "heteroarylene" refers to a divalent heteroaryl derived by removing one hydrogen atom from "heteroaryl", for example, pyridyl becomes pyridylene after removing one hydrogen atom.

[0042] As used in the present invention, the term "single bond" means that groups are directly connected.

[0043] As used in the present invention, the term "substituted or unsubstituted" means that a hydrogen atom in a compound is replaced by a non-hydrogen group or not replaced by a non-hydrogen group. The number of substituents is not limited as long as it can be obtained by a chemical reaction. It is not limited to a specific position as long as the hydrogen at that position can be replaced by a substituent.

[0044] "Unsubstituted" means retaining a hydrogen atom, and in this case, the hydrogen atom includes protium, deuterium, and tritium.

[0045] When there are two or more substituents, the two or more substituents may be the same or different.

[0046] Organic electroluminescent element

[0047] The structure used in the organic electroluminescent element of the present invention is a publicly known structure, which includes an anode, a cathode, and an organic layer located between the anode and the cathode. The organic layer includes a light-emitting layer, and at least one layer of the organic layer includes the compound of the present invention.

[0048] The organic layer may further include one or more of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer, but is not limited thereto.

[0049] The light-emitting element of the present invention may be fluorescent light-emitting, phosphorescent light-emitting, or a combination of them. The light-emitting element may be single light-emitting or a series type of multiple light-emitting units.

[0050] Examples of simple light-emitting elements include, but are not limited to, the following:

[0051] (1) Hole transport layer / fluorescent light-emitting layer / electron transport layer;

[0052] (2) Hole transport layer / phosphorescent light-emitting layer / electron transport layer;

[0053] (3) Hole transport layer / first fluorescent light-emitting layer / second fluorescent light-emitting layer / electron transport layer;

[0054] (4) Hole transport layer / first phosphorescent light-emitting layer / second phosphorescent light-emitting layer / electron transport layer;

[0055] (5) Hole transport layer / fluorescent light-emitting layer / spacer layer / phosphorescent light-emitting layer / electron transport layer;

[0056] (6) Hole transport layer / electron blocking layer / fluorescent light-emitting layer / electron transport layer;

[0057] (7) Hole transport layer / electron blocking layer / fluorescent light-emitting layer / hole blocking layer / electron transport layer;

[0058] (8) Hole transport layer / electron blocking layer / phosphorescent light-emitting layer / electron transport layer;

[0059] (9) Hole transport layer / electron blocking layer / phosphorescent light-emitting layer / hole blocking layer / electron transport layer;

[0060] (10) Hole injection layer / hole transport layer / phosphorescent light-emitting layer / electron transport layer / electron injection layer;

[0061] (11) Hole injection layer / hole transport layer / fluorescent light-emitting layer / electron transport layer / electron injection layer;

[0062] (12) Hole injection layer / hole transport layer / electron blocking layer / phosphorescent light-emitting layer / electron transport layer / electron injection layer;

[0063] (13) Hole injection layer / hole transport layer / electron blocking layer / fluorescent light-emitting layer / electron transport layer / electron injection layer;

[0064] Each of the above phosphorescent / fluorescent light-emitting layers can emit light of different colors.

[0065] As a tandem organic electroluminescent device, it can be an anode / first light-emitting unit / intermediate layer / second light-emitting unit / cathode. The intermediate layer can generally also be referred to as a charge generation layer, an electron extraction layer, a linking layer, etc. For example, when stacking a fluorescent light-emitting layer and a phosphorescent light-emitting layer, in order to prevent the excitons generated in the phosphorescent light-emitting layer from diffusing to the fluorescent light-emitting layer or to adjust the carrier balance, an intermediate layer is placed between the fluorescent light-emitting layer and the phosphorescent light-emitting layer.

[0066] When the organic light-emitting device includes a plurality of organic layers, the organic layers can be formed of the same material or different materials.

[0067] The organic electroluminescent device of the present specification can be manufactured by materials and methods known in the art, except that one or more of the organic layers are formed by using a compound of Formula I.

[0068] As the anode material, a material having a relatively large work function can be used, and a transparent conductive oxide, a metal, a conductive polymer, etc. can be used. Specific examples of the anode material include: metals such as vanadium, chromium, copper, zinc, and gold, or alloys thereof; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of metals and oxides such as ZnO:Al or SnO 2 :Sb; conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDOT), polypyrrole, and polyaniline, etc., but not limited thereto.

[0069] As the cathode material, a material having a low work function is usually used to facilitate electron injection into the organic layer, and a metal, a metal oxide, a conductive polymer, etc. can be used. Specific examples of the cathode material include: metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or alloys thereof; multilayered structure materials such as LiF / Al or LiO 2 / Al, etc., but not limited thereto.

[0070] The hole injection layer is a layer that injects holes from the electrode and has the ability to transport holes. In order to reduce the energy level difference between the electrodes, the hole injection layer is mainly prepared based on aromatic amine compounds, and can also be prepared with the following materials. For example, copper phthalocyanine is selected from metal complexes, and HATCN (2,3,6,7,10,11 - hexacyano - 1,4,5,8,9,12 - hexaazatriphenylene) with a phenylene structure is selected from materials with the lowest unoccupied molecular orbital energy level. When used as a light - emitting host and a dopant, a derivative of F4 - TCNQ (2,3,5,6 - tetrafluoro - 7,7',8,8' - tetracyano - p - quinodimethane) with the lowest unoccupied molecular orbital energy level can be doped in the aromatic amine compound.

[0071] The hole transport layer is a layer that receives holes from the hole injection layer and transports the holes to the light - emitting layer. And the hole transport material can appropriately be a material with a high hole mobility that can receive holes from the anode or the hole injection layer and transfer the holes to the light - emitting layer. Arylamine - based derivatives, triphenyldiamine derivatives, etc. can be used, and low - molecular or high - molecular materials can also be used.

[0072] The light - emitting material is a material that can receive holes and electrons from the hole transport layer and the electron transport layer respectively and combine the holes and electrons to emit light in the visible light region. The light - emitting layer material includes a host material and a dopant material. Red, green, or blue light - emitting materials can be used, and if necessary, two or more light - emitting materials can be mixed. As the light - emitting material, fluorescent materials can be used, and phosphorescent materials can also be used. As the light - emitting material, single - component materials can be used, or multi - component materials can be used.

[0073] The electron transport layer is a layer that receives electrons from the electron injection layer and transports the electrons to the light - emitting layer. And the electron transport material can be a material with a high electron mobility that can receive electrons from the cathode and transfer the electrons to the light - emitting layer. Metal complexes such as triazine derivatives, oxadiazole derivatives, benzoquinone and its derivatives, naphthoquinone and its derivatives, anthraquinone and its derivatives, fluorenone derivatives, diphenyldicyanoethylene and its derivatives, 8 - hydroxyquinoline and its derivatives, etc. can be used, and high - molecular materials and small - molecular materials can also be used.

[0074] The electron injection layer is a layer that injects electrons from the electrode. In this application, LiF is used. However, this application is not limited thereto.

[0075] The hole blocking layer is a layer that blocks holes from reaching the cathode.

[0076] The electron blocking layer is a layer that blocks electrons from reaching the anode.

[0077] According to the materials used, the organic light - emitting device of this specification can be a top - emitting device, a bottom - emitting device, or a dual - emission type device.

[0078] The charge generation layer refers to the intermediate layer between the anode and the cathode in a tandem structure element, and is a layer that generates holes and electrons by charge separation. The charge generation layer is usually formed by a P-type layer on the cathode side and an N-type layer on the anode side, and can effectively separate charges and efficiently transport carriers.

[0079] In a specific embodiment of the present invention, in formula (1), L 1 is selected from the following substituted or unsubstituted groups: pyrimidinylene, pyrazinylene, quinoxalinylene, quinazolinylene, phenanthrolinylene, pyridinopyridinylene, pyridinisoquinolinylene;

[0080] L 2 is selected from a single bond, and the following substituted or unsubstituted groups: phenylene, naphthylene, phenanthrylene, anthrylene, triphenylene, fluoranthenylene, pyrenylene, dibenzofuranylene, dibenzothiophenylene, benzofuranylene, benzothiophenylene, furanylene, thiophenylene;

[0081] Ar 1 and Ar 2 are each independently selected from hydrogen, deuterium, halogen, and the following substituted or unsubstituted groups: phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthryl, triphenyl, fluoranthenyl, pyrenyl, perylenyl, fluorenyl, 9,9'-dimethylfluorenyl, 9,9'-diphenylfluorenyl, furanyl, benzofuranyl, thiophenyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, pyridyl, bipyridyl, terpyridyl, pyrimidinyl, pyrazinyl, quinolinyl, isoquinolinyl, quinoxalinyl, quinazolinyl, phenanthrolinyl, indolopyridinyl, indolopyrimidinyl, carbazolyl, phthalazinyl.

[0082] Preferably, L 1 is selected from substituted or unsubstituted phenanthrolinylene.

[0083] In a specific embodiment of the present invention, in formula (1), L 2 is selected from the following substituted or unsubstituted groups: pyrimidinylene, pyrazinylene, quinoxalinylene, quinazolinylene, phenanthrolinylene, pyridinopyridinylene, pyridinisoquinolinylene;

[0084] L 1 is selected from a single bond, and the following substituted or unsubstituted groups: phenylene, naphthylene, phenanthrylene, anthrylene, triphenylene, fluoranthenylene, pyrenylene, dibenzofuranylene, dibenzothiophenylene, benzofuranylene, benzothiophenylene, furanylene, thiophenylene;

[0085] Ar 1 and Ar 2Each is independently selected from hydrogen, deuterium, a halogen, and a substituted or unsubstituted group selected from the following: phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthryl, triphenylene, fluoranthenyl, pyrenyl, perylenyl, fluorenyl, 9,9'-dimethylfluorenyl, 9,9'-diphenylfluorenyl, furyl, benzofuryl, thienyl, benzothienyl, dibenzofuryl, dibenzothienyl, pyridyl, bipyridyl, terpyridyl, pyrimidinyl, pyrazinyl, quinolinyl, isoquinolinyl, quinoxalinyl, quinazolinyl, phenanthrolinyl, indolopyridinyl, indolopyrimidinyl, carbazolyl, phthalazinyl.

[0086] Preferably, L 2 is selected from a substituted or unsubstituted phenanthrolinyl group.

[0087] In a specific embodiment of the present invention, in formula (1), L 1 , L 2 are each independently selected from a substituted or unsubstituted group selected from the following: pyrimidinyl, pyrazinyl, quinoxalinyl, quinazolinyl, phenanthrolinyl, pyridinopyridinyl, pyridinisoquinolinyl;

[0088] Ar 1 、Ar 2 Each is independently selected from hydrogen, deuterium, a halogen, and a substituted or unsubstituted group selected from the following: phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthryl, triphenylene, fluoranthenyl, pyrenyl, perylenyl, fluorenyl, 9,9'-dimethylfluorenyl, 9,9'-diphenylfluorenyl, furyl, benzofuryl, thienyl, benzothienyl, dibenzofuryl, dibenzothienyl, pyridyl, bipyridyl, terpyridyl, pyrimidinyl, pyrazinyl, quinolinyl, isoquinolinyl, quinoxalinyl, quinazolinyl, phenanthrolinyl, indolopyridinyl, indolopyrimidinyl, carbazolyl, phthalazinyl.

[0089] Preferably, L 1 , L 2 are each independently selected from a substituted or unsubstituted phenanthrolinyl group.

[0090] In a specific embodiment of the present invention, the benzimidazole derivative is selected from any one of the following compounds numbered 1 to 40:

[0091]

[0092]

[0093]

[0094] Those skilled in the art can synthesize the compounds of the present invention by referring to the synthesis of the following compounds and known synthesis methods.

[0095] Synthesis general formula: The following general formula is only one synthesis method of the compounds of the present invention, and the compounds of the present invention can also be synthesized by other methods.

[0096]

[0097] For different substitution positions, the same synthesis method can be adopted. L 1 and L 2 、Ar 1 、Ar 2 have the same meanings as those represented in Claim 1.

[0098] Synthesis of Compound No. 1 in Synthesis Example 1

[0099] Synthesis route:

[0100]

[0101] Under a nitrogen atmosphere, compound A (6.98 g, 23.74 mmol), 2-phenyl-9-bromo-1,10-phenanthroline (8.34 g, 24.97 mmol), palladium acetate (0.16 g, 0.71 mmol), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (1.13 g, 2.36 mmol) and sodium tert-butoxide (4.55 g, 47.40 mmol) were added to 150 mL of toluene, and the reaction solution was refluxed for 8 hours and then cooled to room temperature. After suction filtration, the filtrate was concentrated and crystallized, and after suction filtration, it was recrystallized with toluene to obtain a white solid compound 1 (7.50 g, yield 58%).

[0102] LC-MS (APCI) [M + H] + = 549.45

[0103] 1 HNMR (400 MHz, DMSO-d6) δ 8.94–8.87 (m, 3H), 8.57 (d, 1H), 8.50–8.45 (m, 2H), 8.42 (d, 1H), 8.24 (d, 2H), 8.03–7.93 (m, 4H), 7.84–7.73 (m, 2H), 7.69 (ddd, 1H), 7.66–7.59 (m, 3H), 7.56 (tdd, 4H), 7.24 (d, 1H).

[0104] The following application examples further illustrate the application of the benzimidazole derivatives described in the present invention and the organic electroluminescent devices containing the same.

[0105] Application Example 1

[0106] An organic electroluminescent device, such as Figure 1As shown, it includes a first electrode layer 1, a hole injection layer 2, a hole transport layer 3, a light-emitting layer 4, an electron transport layer 5, an N-type charge generation layer 6, a P-type charge generation layer 7, a hole transport layer 8, a light-emitting layer 9, an electron transport layer 10, an electron injection layer 11, and a second electrode layer 12 which are stacked. Among them, 100 is the first light-emitting unit and 200 is the second light-emitting unit.

[0107] The specific component structure is as follows:

[0108] ITO (100 nm) / NPD:F4-TCNQ (10%)(10 nm) / NPD (120 nm) / BH:BD (3%)(20 nm) / TmPyPB (10 nm) / Bphen:Li (2%)(10 nm) / NPD:F4-TCNQ (10%)(20 nm) / NPD (20 nm) / BH:BD (3%)(20 nm) / Alq 3 (10 nm) / LiF (0.5 nm) / Al (200 nm).

[0109] The process of component preparation:

[0110] The bottom-emitting glass substrate used in this embodiment is purchased from Guangdong Xinyi Display Technology Co., Ltd., and 100 nm ITO is used as the first electrode layer 1. First, the bottom-emitting glass substrate is cleaned successively with ITO cleaning agent, deionized water, and isopropanol, and then the bottom-emitting glass substrate is baked at 180 degrees Celsius for 30 minutes to make it dry.

[0111] Then the bottom-emitting glass substrate is placed in the evaporation chamber, and the vacuum degree is about 10 -8In the case of the support, each organic layer was sequentially deposited on the ITO anode by thermal vacuum evaporation at a rate of 0.2 - 2 Å / sec. Among them, F4-TCNQ (mass content 10%) was incorporated into NPD to form a thickness of 10 nm as the hole injection layer. NPD was formed to a thickness of 120 nm as the hole transport layer. On the anthracene host ADN (9,10-di(naphtha-2-yl-)anthracene), a pyrene dopant 1,6-bis(diphenylamino)pyrene with a mass content of 3% was doped to form a blue light-emitting layer with a thickness of 20 nm. TmPyPB was formed to a thickness of 10 nm as the first electron transport layer. In BPhen (4,7-Diphenyl-1,10-phenanthroline), Li with a mass content of 2% was doped to form an N-type charge generation layer 6 with a thickness of 10 nm. On NPD, F4-TCNQ with a mass content of 10% was doped to form a P-type charge generation layer with a thickness of 20 nm. NPD was formed to a thickness of 20 nm as the hole transport layer. On the anthracene host ADN (9,10-di(naphtha-2-yl-)anthracene), a pyrene dopant 1,6-bis(diphenylamino)pyrene with a mass content of 3% was doped to form a blue light-emitting layer with a thickness of 20 nm. Alq 3 (Tris-(8-hydroxyquinolinato)aluminum) was formed to a thickness of 10 nm as the second electron transport layer. LiF was formed to a thickness of 0.5 nm as the electron injection layer. Al was formed to a thickness of 200 nm as the cathode.

[0112] Finally, the device was transferred back to the glove box and encapsulated with a glass cover and a desiccant to complete the device, denoted as organic electroluminescent device 1.

[0113]

[0114] Comparative structure

[0115] Bphen(4,7-Diphenyl-1,10-phenanthroline)

[0116]

[0117] Examples and comparative examples

[0118] For the charge generation layer, the compound prepared in Example 1 of the present invention was used to replace the Bphen material to prepare the N-type charge generation layer 6, and the organic electroluminescent device 2 was fabricated by the same method.

[0119] Lifetime test method: Apply a voltage to the obtained organic electroluminescent device so that the current density reaches 30 mA / cm 2 , and measure the time (LT95 (unit: hours)) until the luminance becomes 95% of the initial luminance.

[0120] The current efficiency is tested at a current density of 15 mA / cm 2 , and the results are shown in Table 1.

[0121] Table 1

[0122]

[0123]

[0124] According to the results in Table 1, it can be seen that the organic electroluminescent device 2 prepared with the compound of the present invention has higher current efficiency and longer service life compared with the organic electroluminescent device 1, improving the comprehensive performance of the device. Therefore, it is suitable for preparing an organic electroluminescent device as an N-type charge generation layer.

[0125] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

Claims

1. A benzimidazole derivative, characterized in that The compound has the structure shown in formula (1). wherein L 1 、L 2 At least one of them is selected from substituted or unsubstituted N-containing heteroaryls having 6 to 30 ring atoms, and the other, which is not an N-containing heteroaryl, is selected from a single bond, substituted or unsubstituted arylenes having 6 to 30 ring atoms, and substituted or unsubstituted heteroarylenes having 5 to 30 ring atoms. Ar 1 、Ar 2 each independently selected from hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted aryl having 6-30 ring atoms, substituted or unsubstituted heteroaryl having 5-30 ring atoms, when the "substituted or unsubstituted" is substituted, the substituents are each independently selected from one or a combination of deuterium, halogen, cyano, C1-C10 alkyl, C3-C10 cycloalkyl, C6-C30 aryl, and C3-C30 heteroaryl; the heteroatoms of the heteroaryl are selected from one or more of oxygen, sulfur, and nitrogen.

2. The benzimidazole derivative according to claim 1, characterized in that: the number of N in the N-containing heteroaryl with 6-30 ring atoms is at least 2 and contains no other heteroatoms.

3. The benzimidazole derivative according to claim 1, characterized in that: the N-containing heteroaryl with 6-30 ring atoms is selected from pyrimidinyl, pyrazinyl, quinoxalinyl, quinazolinyl, phenanthrolinyl, pyridinopyridinyl, and pyridinopyridoisoquinolinyl; L 1 、L 2 Another group that is not a N-containing heteroaryl group among L 1 and L 2 is selected from a single bond and the following substituted or unsubstituted groups: phenylene, naphthylene, phenanthrylene, anthrylene, triphenylene, fluoranthenylene, pyrenylene, dibenzofuranylene, dibenzothiophenylene, benzofuranylene, benzothiophenylene, furanylene, thiophenylene.

4. The benzimidazole derivative according to claim 1, characterized in that: Ar 1 and Ar 2 are each independently selected from hydrogen, deuterium, a halogen, and a substituted or unsubstituted group such as phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthryl, triphenylene, fluoranthenyl, pyrenyl, perylenyl, fluorenyl, 9,9'-dimethylfluorenyl, 9,9'-diphenylfluorenyl, furyl, benzofuryl, thienyl, benzothienyl, dibenzofuryl, dibenzothienyl, pyridyl, bipyridyl, terpyridyl, pyrimidinyl, pyrazinyl, quinolinyl, isoquinolinyl, quinoxalinyl, quinazolinyl, phenanthrolinyl, indolopyridyl, indolopyrimidinyl, carbazolyl, and phthalazinyl.

5. The benzimidazole derivative according to claim 1, characterized in that the benzimidazole derivative is selected from any one of the following compounds numbered 1 to 40:

6. Use of the benzimidazole derivative according to any one of claims 1-5 as a material for an organic electroluminescent element.

7. An organic electroluminescent element, comprising an anode, a cathode, and an organic layer located between the anode and the cathode, characterized in that, the organic layer contains the benzimidazole derivative according to any one of claims 1-5.

8. The organic electroluminescent element according to claim 8, characterized in that, the organic layer contains an electron transport layer and a light-emitting layer, and the electron transport layer contains the benzimidazole derivative according to any one of claims 1-5.

9. The organic electroluminescent element according to claim 9, characterized in that, the organic layer contains at least two light-emitting units, a charge generation layer is included between the light-emitting units, the light-emitting units contain an electron transport layer, and at least one of the charge generation layer or / and at least one electron transport layer contains the benzimidazole derivative according to any one of claims 1-5.

10. An electronic device, including one or several of a display, a monitor, and a lighting device, and including the organic electroluminescent element according to claim 7.

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