Fluorene benzofuran compound and organic electroluminescent device thereof

Abstract

The invention provides a fluorene benzofuran compound and an organic electroluminescent device thereof. The fluorene benzofuran compound disclosed by the invention has a structure as shown in a formula (I). The compound has high thermal stability and high chemical stability, and the service life of a device can be prolonged; and the stability and the luminous efficiency of the device are further improved by utilizing the mutual steric hindrance, and the driving voltage of the device is reduced. The compound has a highly three-dimensional rigid structure, has good film-forming property and thermal stability, and is very suitable for preparing various luminescent devices, especially blue light organic electroluminescent devices. The light-emitting device prepared from the fluorene benzofuran compound has the advantages of low driving voltage, high light-emitting efficiency and long service life. The preparation method of the compound is simple, raw materials are easy to obtain, and the development requirement of industrial large-scale production can be met.

Description

Technical Field

[0001] The present invention relates to the field of organic electroluminescent materials, and in particular to a fluorenylbenzofuran compound. Background Art

[0002] Organic Light Emitting Diode (OLED) is a display lighting technology that has gradually developed in recent years. Especially in the display industry, OLED display has attracted widespread attention due to its advantages such as high response, high contrast, and flexibility.

[0003] The pixel units of current full-color OLED displays are composed of the three primary colors of red, green, and blue. Based on the principle of three primary colors, various colors can be generated by controlling the grayscale levels of red, green, and blue in the sub-pixels, thus displaying a full-color image. In three-color light-emitting devices, blue emitters have higher energy than red and green emitters, allowing them to transfer energy to lower-energy organic light-emitting materials such as green, yellow, and red. Furthermore, based on the principle of primary colors, blue emission is fundamental to achieving white and color displays. Furthermore, the lifespan of blue OLEDs remains insufficient compared to red and green OLEDs. Currently, the light-emitting layers of blue organic electroluminescent devices almost exclusively utilize a host-guest doping system, where electroluminescence is achieved by doping a host material with a guest dopant. Currently, the blue host materials used in the light-emitting layer are primarily compounds derived from anthracene with aromatic groups substituted at the 9- and 10-positions. These aromatic groups primarily include benzene, naphthalene, anthracene, dibenzofuran, dibenzothiophene, benzodibenzofuran, and benzodibenzothiophene. However, the performance of devices made from various currently designed blue-light host materials still needs to be improved, especially in terms of efficiency, lifespan, voltage, etc. To meet people's higher requirements for OLED devices, the field urgently needs to develop more types of blue-light host materials with higher performance. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides a fluorenylbenzofuran compound, which can improve the driving voltage, luminous efficiency and short life of an organic electroluminescent device.

[0005] The present invention provides a fluorenylbenzofuran compound having a structure shown in formula (I):

[0006]

[0007] in,

[0008] Ar1 is selected from substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl;

[0009] R1 and R2 are the same or different and are independently selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C2-C30 heteroaryl;

[0010] R3-R7 are the same or different and are independently selected from hydrogen, deuterium, tritium, halogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl; or two adjacent R3 are linked together to form a substituted or unsubstituted ring, or two adjacent R4 are linked together to form a substituted or unsubstituted ring;

[0011] L1-L2 are the same or different and are independently selected from a single bond, or a substituted or unsubstituted C6-C30 arylene group, or a substituted or unsubstituted C2-C30 heteroarylene group;

[0012] n is the same or different and is independently selected from 0, 1, 2, 3 or 4.

[0013] The present invention also provides an organic electroluminescent device, comprising a first electrode, a second electrode opposite to the first electrode, and at least one organic layer sandwiched between the first electrode and the second electrode, wherein the at least one organic layer contains the fluorenylbenzofuran compound.

[0014] The present invention provides a series of novel fluorenylbenzofuran compounds and light-emitting devices thereof. The compounds of the present invention have high thermal stability and high chemical stability due to their own rigid skeleton structure, and are ultimately applied to light-emitting devices, thereby improving the service life of the devices. By utilizing the steric hindrance between the two, the stability and luminous efficiency of the devices are further improved, and the driving voltage of the devices is reduced. For the fluorenylbenzofuran compounds disclosed so far, the present invention designs a unique structure, and uses fluorene substitution to increase the large steric hindrance between the adjacent positions of the anthracene material, thereby achieving a highly stereoscopic molecular conformation of the fluorenylbenzofuran compounds, making the most of the steric effect and maintaining the electronic and photophysical properties of the dibenzofuran structure. This type of connection method is particularly suitable for constructing blue light host materials, and can obtain a host molecule with a steric structure at the same time. While improving the molecular arrangement, it can also prevent the aggregation effect, thereby ensuring the carrier mobility and avoiding the reduction in quantum efficiency caused by aggregation. In addition, a relatively concentrated electronic conjugated system is formed, which is conducive to the transmission of electrons, realizes the reduction of voltage, and ultimately achieves the improvement of the light-emitting device. The fluorenylbenzofuran compounds of the present invention possess a highly stereoscopic, rigid structure, excellent film-forming properties, and thermal stability. These fluorenylbenzofuran compounds are highly suitable for preparing various light-emitting devices, particularly blue organic electroluminescent devices. Light-emitting devices made from these fluorenylbenzofuran compounds exhibit low driving voltage, high luminous efficiency, and long device life.

[0015] The fluorenylbenzofuran compounds of the present invention have adjustable carrier transport properties, adjustable HOMO and LUMO energy levels, and suitable singlet and triplet energy levels, making them suitable as constituent materials for the light-emitting layer in organic electroluminescent devices, particularly as host materials. Light-emitting devices prepared using these materials, particularly blue-emitting organic electroluminescent devices, exhibit low driving voltage, high luminous efficiency, and long device life, significantly outperforming existing organic electroluminescent devices. Furthermore, the preparation method of the fluorenylbenzofuran compounds of the present invention is simple, and the raw materials are readily available, meeting the development needs of industrial-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the structure of an organic electroluminescent device.

[0017] Explanation of the reference numerals: 1 substrate; 2 anode; 3 hole injection layer; 4 hole transport layer; 5 electron blocking layer; 6 light-emitting layer; 7 hole blocking layer; 8 electron transport layer; 9 electron injection layer; 10 cathode.

[0018] Figure 2 Fluorescence emission spectrum of Example device 1. DETAILED DESCRIPTION

[0019] The following will be a clear and complete description of the technical solutions of the specific embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] In the compounds of the present invention, any atom not designated as a specific isotope is included as any stable isotope of that atom, and includes the atom at both its natural isotopic abundance and unnatural abundance.

[0021] Unless otherwise specified, the term "alkyl" refers to a monovalent saturated aliphatic hydrocarbon group, a straight or branched chain group containing 1 to 30 carbon atoms, preferably containing 1 to 15 carbon atoms, 1 to 10 carbon atoms, or 1 to 6 carbon atoms. Examples include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, and the like.

[0022] Unless otherwise specified, the term "cycloalkyl" refers to a monocyclic saturated aliphatic hydrocarbon group having a specific number of carbon atoms, preferably containing 3-30 carbon atoms, preferably containing 3-15 carbon atoms or 3-10 carbon atoms or 3-8 carbon atoms, examples of which include but are not limited to cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantyl, norbornyl, etc.

[0023] Unless otherwise specified, the term "aryl" or "aromatic ring group" refers to a monocyclic, polycyclic, or fused aromatic carbocyclic ring system containing 6 to 30 carbon atoms, or 6 to 25 carbon atoms, or 6 to 14 carbon atoms, or 6 to 10 carbon atoms. The term "aryl" can be used interchangeably with the term "aromatic ring." Examples of aryl groups include, but are not limited to, phenyl, biphenyl, terphenyl, quaterphenyl, 1-phenylnaphthyl, 2-phenylnaphthyl, naphthyl, anthracenyl, phenanthrenyl, triphenylene, pyrenyl, perylenyl, fluoranthenyl, fluorenyl, benzofluorenyl, spirofluorenyl, spirobifluorenyl, and the like.

[0024] Unless otherwise specified, the term "arylene" refers to a radical derived from an aryl radical by removing a hydrogen atom. The arylene radical contains 6 to 30 carbon atoms, or 6 to 25 carbon atoms, or 6 to 14 carbon atoms, or 6 to 10 carbon atoms; examples of arylene radicals include, but are not limited to, phenylene, biphenylene, terphenylene, quaterphenylene, phenylnaphthylene, naphthylene, anthrylene, phenanthrenylene, triphenylene, pyrenylene, perylene, fluoranthenylene, fluorenylene, benzofluorenylene, spirofluorenylene, spirobifluorenylene, and the like.

[0025] Unless otherwise specified, the term "heteroaryl" or "heteroaryl ring group" means a monocyclic, polycyclic or fused ring system containing 2-30 carbon atoms, 2-25 carbon atoms, or 2-14 carbon atoms, or 3-10 carbon atoms, in which 1, 2, 3 or more of the ring atoms are heteroatoms independently selected from oxygen, sulfur, nitrogen, silicon, selenium or phosphorus atoms and the remaining atoms are carbon. Examples of heteroaryl groups include, but are not limited to, pyrrolyl, furanyl, thienyl, oxazolyl, thiazolyl, imidazolyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, bipyridyl, bipyrimidinyl, phenylpyridyl, phenylpyrimidinyl, spiroxanthenyl, spiroxanthenyl, acridinyl, 9,10-dihydroacridinyl, naphthyridinyl, indolyl, phenoxazinyl, phenothiazinyl, phenoxathiyl, quinolinyl, isoquinolinyl, , benzoquinolinyl, benzoisoquinolinyl, quinazoline, benzoquinazolinyl, quinoxalinyl, benzoquinoxalinyl, o-phenanthroline, benzofuranyl, dibenzofuranyl, naphthiobenzofuranyl, benzothienyl, benzothiazolyl, dibenzothienyl, naphthiobenzothienyl, benzoxazolyl, naphthioxazolyl, benzimidazolyl, naphthiazolyl, benzothiazolyl, naphthiozolyl, carbazolyl, benzocarbazolyl, and the like.

[0026] Unless otherwise specified, the term "heteroarylene" refers to a radical derived from a heteroaryl radical by removing a hydrogen atom. A heteroarylene radical contains 2-30 carbon atoms, 2-25 carbon atoms, or 2-14 carbon atoms, or 3-10 carbon atoms, wherein one, two, three or more ring atoms are heteroatoms and the remaining atoms are carbon, the heteroatoms being independently selected from oxygen, sulfur, nitrogen, silicon, selenium, or phosphorus atoms. Examples of heteroarylene radicals include, but are not limited to, pyridylene, pyrimidylene, triazinylene, dibenzofuranylene, dibenzothiophenylene, carbazolylene, and the like.

[0027] Unless otherwise specified, the term "halogen" or "halo" refers to F, Cl, Br, and I.

[0028] Unless otherwise indicated, the structural formulas described herein include all isomeric forms (e.g., enantiomers, diastereomers, and geometric isomers (or conformers)): for example, R and S configurations containing asymmetric centers, (Z) and (E) isomers of double bonds, and (Z) and (E) conformers. Therefore, single stereochemical isomers of the compounds of the present invention or mixtures of their enantiomers, diastereomers, or geometric isomers (or conformers) are within the scope of the present invention.

[0029] Unless otherwise specified, the term "substituted" means that a hydrogen atom in certain functional groups is replaced by another atom or functional group (i.e., a substituent), and the position of the substitution is not limited as long as the position is the position where the hydrogen atom is replaced, and when two or more substituents are substituted, the two or more substituents may be the same as or different from each other.

[0030] Unless otherwise specified, the term "substituted or unsubstituted" means not substituted or substituted with one or more substituents selected from the group consisting of deuterium, tritium, halogen, cyano, substituted or unsubstituted C1-C15 alkyl, substituted or unsubstituted C3-C15 cycloalkyl, substituted or unsubstituted C6-C25 aryl, substituted or unsubstituted C2-C25 heteroaryl, amino substituted with substituted or unsubstituted C6-C25 aryl and / or substituted or unsubstituted C2-C25 heteroaryl, and substituted or unsubstituted silyl. Preferably, the "substituted or unsubstituted" means not substituted or substituted by one or more substituents selected from the group consisting of: deuterium, tritium, halogen, cyano, C1-C10 alkyl, halogen-substituted alkyl, C3-C10 cycloalkyl, C6-C14 aryl, C2-C14 heteroaryl, substituted or unsubstituted C6-C14 aryl and / or substituted or unsubstituted C2-C14 heteroaryl substituted amino, substituted or unsubstituted silyl. In the case of being substituted by multiple substituents, the multiple substituents are the same or different from each other. Most preferably, the term "substituted or unsubstituted" means not substituted or substituted with one or more substituents selected from the group consisting of deuterium, tritium, fluorine, chlorine, bromine, iodine, cyano, methyl, trifluoromethyl, deuterated methyl, ethyl, deuterated ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, norbornyl, phenyl, deuterated phenyl, naphthyl, deuterated naphthyl, Anthracenyl, deuterated anthracenyl, phenanthryl, deuterated phenanthryl, triphenylene, pyrenyl, 9,9-dimethylfluorenyl, 9,9-diphenylfluorenyl, spirobifluorenyl, pyridyl, pyrimidinyl, triazinyl, quinolyl, isoquinolyl, quinazolinyl, quinoxalinyl, N-phenylcarbazolyl, N-biphenylcarbazolyl, dibenzofuranyl, dibenzothiophenyl, trimethylsilyl, triphenylsilyl; when substituted with multiple substituents, the multiple substituents may be the same or different.

[0031] Unless otherwise specified, when a substituent on a ring is not indicated as fixed, it represents that the substituent is attached to any of the corresponding optional positions of the ring.

[0032] Unless otherwise specified, when a substituent or a bond at a site of attachment runs through two or more rings, it indicates that it can be attached to any of the two or more rings, specifically any of the corresponding optional sites of the rings.

[0033] Unless otherwise specified, "adjacent groups connected to form a substituted or unsubstituted ring" means that adjacent groups are bonded and optionally aromatized to form a substituted or unsubstituted aromatic ring, heteroaromatic ring, aliphatic ring, or aliphatic heterocycle. Furthermore, the ring formed by the connection includes, but is not limited to, benzene, naphthalene, indene, cyclopentane, cyclohexane, pyridine, and pyrimidine. The term "adjacent groups" includes groups substituted on the same atom, groups substituted on adjacent atoms, and groups adjacent in space.

[0034] It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features described in detail below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they are not listed here one by one.

[0035] In a first aspect, the present invention provides a fluorenylbenzofuran compound having a structure shown in formula (I):

[0036]

[0037] in,

[0038] Ar1 is selected from substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl;

[0039] R1 and R2 are the same or different and are independently selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C2-C30 heteroaryl;

[0040] R3-R7 are the same or different and are independently selected from hydrogen, deuterium, tritium, halogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl; or two adjacent R3 are linked together to form a substituted or unsubstituted ring, or two adjacent R4 are linked together to form a substituted or unsubstituted ring;

[0041] L1-L2 are the same or different and are independently selected from a single bond, or a substituted or unsubstituted C6-C30 arylene group, or a substituted or unsubstituted C2-C30 heteroarylene group;

[0042] n is the same or different and is independently selected from 0, 1, 2, 3 or 4.

[0043] In one embodiment, Ar1 is selected from the group consisting of substituted or unsubstituted phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthrenyl, triphenylene, pyrenyl, 9,9-dimethylfluorenyl, 9,9-diphenylfluorenyl, dibenzofuranyl, dibenzothiophenyl, 9-phenylcarbazolyl, 9-biphenylcarbazolyl, and 9-naphthylcarbazolyl.

[0044] In one embodiment, the substituent in "substituted or unsubstituted" in Ar1 is selected from the group consisting of: deuterium, tritium, halogen, cyano, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted pyridyl.

[0045] In one embodiment, Ar1 is selected from the group consisting of phenyl, deuterated phenyl, biphenyl, deuterated biphenyl, naphthyl, and deuterated naphthyl.

[0046] In one embodiment, R1 and R2 are the same or different and are independently selected from substituted or unsubstituted: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, phenyl, biphenyl, naphthyl.

[0047] In one embodiment, the substituents in "substituted or unsubstituted" in R1 and R2 are selected from: deuterium, tritium, halogen, cyano, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted pyridyl.

[0048] In one embodiment, R3-R7 are the same or different and are independently selected from hydrogen, deuterium, tritium, halogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C6-C14 aryl, substituted or unsubstituted C2-C12 heteroaryl; or two adjacent R3 are linked together to form a substituted or unsubstituted C6-C10 aromatic ring, or two adjacent R4 are linked together to form a substituted or unsubstituted C6-C10 aromatic ring.

[0049] Preferably, R3-R7 are the same or different and are independently selected from hydrogen, deuterium, tritium, fluorine, chlorine, bromine, iodine, trifluoromethyl, substituted or unsubstituted: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, phenyl, biphenyl, terphenyl, pyridyl, pyrimidinyl, naphthyl, anthracenyl, phenanthrenyl, triphenylene, pyrenyl, dibenzofuranyl, dibenzothiophenyl, 9-phenylcarbazolyl, 9-biphenylcarbazolyl, 9-naphthylcarbazolyl; or two adjacent R3 are connected together to form a substituted or unsubstituted: benzene ring, naphthalene ring, or two adjacent R4 are connected together to form a substituted or unsubstituted: benzene ring, naphthalene ring.

[0050] In one embodiment, the substituents in "substituted or unsubstituted" in R3-R7 are selected from the group consisting of: deuterium, tritium, halogen, cyano, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted pyridyl.

[0051] In one embodiment, L1-L2 are the same or different, and are independently selected from a single bond, or substituted or unsubstituted: phenylene, biphenylene, naphthylene, pyridinylene, pyrimidinylene.

[0052] Preferably, L1-L2 are the same or different and are independently selected from a single bond, or one of the following groups:

[0053]

[0054] Among them, R a is selected from deuterium, tritium, halogen, cyano, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C6-C14 aryl, substituted or unsubstituted C2-C12 heteroaryl; or two adjacent R a linked together to form a substituted or unsubstituted C6-C10 aromatic ring;

[0055] a1 is selected from 0, 1, 2, 3 or 4; a2 is selected from 0, 1, 2 or 3; a3 is selected from 0, 1 or 2; a4 is selected from 0, 1, 2, 3, 4, 5 or 6.

[0056] Preferably, R a Selected from hydrogen, deuterium, tritium, fluorine, chlorine, bromine, iodine, cyano, trifluoromethyl, substituted or unsubstituted: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, phenyl, biphenyl, naphthyl, pyridyl, pyrimidinyl.

[0057] Preferably, R a The substituent in "substituted or unsubstituted" is selected from the group consisting of deuterium, tritium, halogen, cyano, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted phenyl, and substituted or unsubstituted pyridyl.

[0058] In one embodiment, the fluorenobenzofuran compound has a structure represented by any one of formula (I-1) to formula (I-6):

[0059]

[0060] wherein Ar2 and Ar3 are the same or different and are independently selected from substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl;

[0061] Ring A is selected from C6-C10 aromatic rings substituted or unsubstituted by one or more R3; Ring B is selected from C6-C10 aromatic rings substituted or unsubstituted by one or more R4;

[0062] n1 is the same or different and is independently selected from 0, 1, 2 or 3; n2 is the same or different and is independently selected from 0, 1 or 2.

[0063] Preferably, Ar2 and Ar3 are the same or different and are independently selected from substituted or unsubstituted C6-C14 aryl and substituted or unsubstituted C2-C12 heteroaryl.

[0064] Preferably, Ar2 and Ar3 are the same or different and are independently selected from substituted or unsubstituted: phenyl, biphenyl, terphenyl, pyridyl, pyrimidinyl, naphthyl, anthracenyl, phenanthrenyl, triphenylene, pyrene, 9,9-dimethylfluorenyl, 9,9-diphenylfluorenyl, dibenzofuranyl, dibenzothiophenyl, 9-phenylcarbazolyl, 9-biphenylcarbazolyl, 9-naphthylcarbazolyl.

[0065] Preferably, the substituent in "substituted or unsubstituted" in Ar2 and Ar3 is selected from: deuterium, tritium, halogen, cyano, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted pyridyl.

[0066] Preferably, the ring A is selected from the group consisting of a benzene ring and a naphthalene ring, which are substituted or unsubstituted with one or more R3.

[0067] Preferably, the ring B is selected from the group consisting of a benzene ring and a naphthalene ring, which are substituted or unsubstituted with one or more R4.

[0068] In the present invention, Ring A and Ring B may be fused at any appropriate position of the benzene ring to be fused therewith.

[0069] Preferably, the fluorenylbenzofuran compound has a structure represented by any one of formula (I-7) to formula (I-9):

[0070]

[0071] wherein n3 is the same or different and is independently selected from 0, 1, 2, 3, 4, 5 or 6.

[0072] In one embodiment, the deuteration rate of the fluorenylbenzofuran compound is 1-99%, preferably, the deuteration rate is 10-90%, and more preferably, the deuteration rate of the fluorenylbenzofuran compound is 60-90%.

[0073] In one embodiment, the fluorenylbenzofuran compound is selected from:

[0074]

[0075]

[0076]

[0077]

[0078] The above lists only some specific structural forms of the fluorene dibenzofuran compounds represented by formula (I), but the present invention is not limited to these listed chemical structures. All chemical structures based on formula (I) and with substituents as defined in the present invention should be included.

[0079] The fluorene dibenzofuran compound represented by formula (I) of the present invention can be prepared by one of the following synthetic routes:

[0080]

[0081] Wherein, X is selected from halogen, preferably chlorine or bromine.

[0082] In a second aspect, the present invention further provides a light-emitting device comprising a first electrode, a second electrode opposite to the first electrode, and at least one organic layer sandwiched between the first electrode and the second electrode, wherein the at least one organic layer comprises the fluorenylbenzofuran compound of the present invention.

[0083] In one embodiment, the light-emitting device is an organic electroluminescent device; preferably, the light-emitting device is a blue organic electroluminescent device.

[0084] In one embodiment, the organic layer includes a light-emitting layer, and the light-emitting layer contains the fluorenylbenzofuran compound of the present invention.

[0085] In one embodiment, the organic layer includes a light-emitting layer, the light-emitting layer includes a host material, and the host material includes the fluorenylbenzofuran compound of the present invention.

[0086] In one embodiment, Figure 1 As shown, the organic electroluminescent device of the present invention is obtained by sequentially arranging various layers (for example, an anode 2, a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light-emitting layer 6, a hole blocking layer 7, an electron transport layer 8, an electron injection layer 9 and a cathode 10) on a substrate 1.

[0087] The organic electroluminescent device of the present invention is not limited to such a structure. For example, in the multilayer structure, one or some of the organic layers can be omitted. For example, the hole blocking layer 7 between the light-emitting layer 6 and the electron transport layer 8 can be omitted, and the anode 2, the hole injection layer 3, the hole transport layer 4, the electron blocking layer 5, the light-emitting layer 6, the electron transport layer 8, the electron injection layer 9 and the cathode 10 are sequentially arranged on the substrate 1. Alternatively, the hole injection layer 3 between the anode 2 and the hole transport layer 4, the hole blocking layer 7 between the light-emitting layer 6 and the electron transport layer 8, and the electron injection layer 9 between the electron transport layer 8 and the cathode 10 can be omitted at the same time, and the anode 2, the hole transport layer 4, the electron blocking layer 5, the light-emitting layer 6, the electron transport layer 8 and the cathode 10 are sequentially arranged on the substrate 1 to finally obtain the corresponding organic electroluminescent device.

[0088] The organic electroluminescent device of the present invention is not limited to such a structure. For example, in the multilayer structure, one or some of the organic layers can be omitted. For example, the hole blocking layer 7 between the light-emitting layer 6 and the electron transport layer 8 can be omitted, and the anode 2, the hole injection layer 3, the hole transport layer 4, the electron blocking layer 5, the light-emitting layer 6, the electron transport layer 8, the electron injection layer 9 and the cathode 10 are sequentially arranged on the substrate 1. Alternatively, the hole injection layer 3 between the anode 2 and the hole transport layer 4, the hole blocking layer 7 between the light-emitting layer 6 and the electron transport layer 8, and the electron injection layer 9 between the electron transport layer 8 and the cathode 10 can be omitted at the same time, and the anode 2, the hole transport layer 4, the electron blocking layer 5, the light-emitting layer 6, the electron transport layer 8 and the cathode 10 are sequentially arranged on the substrate 1 to finally obtain the corresponding organic electroluminescent device.

[0089] The anode of the organic electroluminescent device of the present invention can be composed of known electrode materials. For example, electrode materials with a large work function can be used, such as metals such as vanadium, chromium, copper, zinc, and gold, or their alloys; 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 SnO2:Sb; and conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDOT), polypyrrole, and polyaniline. Among these, ITO is preferred.

[0090] As the hole injection layer of the organic electroluminescent device of the present invention, known materials with hole injection properties can be used. For example, porphyrin compounds represented by copper phthalocyanine, naphthalenediamine compounds, star-shaped triphenylamine compounds, aromatic amine compounds having a structure in which three or more triphenylamine structures are connected by a single bond or a divalent group containing no heteroatoms, triphenylamine trimers and tetramers, acceptor-type dibenzofuran compounds such as hexacyanoazatriphenylene, and coating-type polymer materials. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet methods.

[0091] As the hole transport layer of the organic electroluminescent device of the present invention, a well-known material with hole transport properties can be used. In addition, other well-known materials with hole transport properties can also be used. For example, compounds containing m-carbazolylphenyl; such as N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (TPD), N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), N,N,N',N'-tetraphenylbenzidine and other benzidine derivatives; 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC); various triphenylamine trimers and tetramers; 9,9',9"-triphenyl -9H,9'H,9"H-3,3':6',3"-tricarbazole (Tris-PCz), etc. These can be formed into films alone or as a single layer formed by mixing with other materials. They can also be formed into a stacked structure of layers formed from individual films, a stacked structure of layers formed from mixed films, or a stacked structure of layers formed from individual films and layers formed from mixed films. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet methods.

[0092] In addition, materials commonly used in the hole injection layer or hole transport layer may be further P-doped with tribromoaniline antimony hexachloride, a radialene derivative, or a polymer compound partially having a structure of a benzidine derivative such as TPD.

[0093] As the electron blocking layer of the organic electroluminescent device of the present invention, a well-known material with electron blocking properties can be used. In addition, other well-known compounds with electron blocking effects can also be used to form it. For example, carbazole derivatives such as 4,4',4"-tris(N-carbazolyl)triphenylamine (TCTA), 9,9-bis[4-(carbazol-9-yl)phenyl]fluorene, 1,3-bis(carbazol-9-yl)benzene (mCP), 2,2-bis(4-carbazol-9-ylphenyl)adamantane (Ad-Cz); compounds with triphenylsilyl and triarylamine structures represented by 9-[4-(carbazol-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene Compounds with electron-blocking properties, such as monoamine compounds with high electron-blocking properties and various triphenylamine dimers, can be used alone or in a single layer by mixing with other materials. They can also be used in a laminated structure of layers formed from individual films, a laminated structure of layers formed from mixed films, or a laminated structure of layers formed from individual films and mixed films. These materials can be formed into thin films using known methods such as vapor deposition, spin coating, and inkjet methods.

[0094] The light-emitting layer of the organic electroluminescent device of the present invention preferably comprises a fluorene dibenzofuran compound represented by formula (I) of the present invention. In addition, various metal complexes such as metal complexes of hydroxyquinoline derivatives headed by Alq3, compounds having a pyrimidine ring structure, anthracene derivatives, bis(vinylbenzene) derivatives, pyrene derivatives, oxazole derivatives, and poly(p-phenylene vinylene) derivatives can also be used.

[0095] The light-emitting layer can be composed of a host material and a dopant material. As the host material, it is preferred to include a fluorene dibenzofuran compound represented by formula (I) of the present invention. In addition, mCBP, mCP, thiazole derivatives, benzimidazole derivatives, polydialkylfluorene derivatives, dibenzofuran compounds having an indole ring as a partial structure of the fused ring, etc. can also be used. As the dopant material, it is preferred to include a dibenzofuran derivative of the present invention. In addition, aromatic amine derivatives, styrylamine compounds, boron complexes, fluoranthene compounds, metal complexes, etc. can also be used. For example, pyrene derivatives, anthracene derivatives, quinacridone, coumarin, rubrene, perylene and their derivatives, benzopyran derivatives, rhodamine derivatives, aminostyryl derivatives, spirocyclic bisfluorene derivatives, etc. can be listed. These materials can be formed into films alone or mixed with other materials to form a single layer. They can also be used in the form of a laminated structure of layers formed alone, a laminated structure of layers formed as a mixture, or a laminated structure of layers formed alone and layers formed as a mixture. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet.

[0096] Preferably, the mass ratio of the host material to the doping material in the light-emitting layer may be 50-99:1-50, and preferably, the mass ratio may be 80-99:1-20.

[0097] As the hole blocking layer of the organic electroluminescent device of the present invention, a known material with hole blocking properties can be used. In addition, other compounds with hole blocking properties can also be used to form. For example, phenanthroline derivatives such as 2,4,6-tris (3-phenyl) -1,3,5-triazine (T2T), 1,3,5-tris (1-phenyl-1H-benzimidazole-2-yl) benzene (TPBi), bathocuproine (BCP), metal complexes of quinolinol derivatives such as aluminum (III) bis (2-methyl-8-hydroxyquinoline) -4-phenylphenolate (BAlq), and various rare earth complexes, oxazole derivatives, triazole derivatives, triazine derivatives, etc. have hole blocking effects. They can be formed into a film alone, or used in the form of a single layer formed by mixing a film with other materials, or can be made into a stacked structure of layers formed by separate film formation, a stacked structure of layers formed by mixed film formation, or a stacked structure of layers formed by separate film formation and a layer formed by mixed film formation. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet.

[0098] The above-mentioned hole-blocking material can also be used to form the electron transport layer described below. That is, by using the above-mentioned known hole-blocking material, a layer serving as both a hole-blocking layer and an electron transport layer can be formed.

[0099] As the electron transport layer of the organic electroluminescent device of the present invention, a well-known material with electron transport properties can be used. In addition, other compounds with electron transport properties can also be used. For example, metal complexes of hydroxyquinoline derivatives headed by Alq3 and BAlq; various metal complexes; triazole derivatives; triazine derivatives; oxadiazole derivatives; pyridine derivatives; bis(10-hydroxybenzo[H]quinoline)beryllium (Be(bq)2); benzimidazole derivatives such as 2-[4-(9,10-dinaphthyl-2-anthracen-2-yl)phenyl]-1-phenyl-1H-benzimidazole (ETL); thiadiazole derivatives; anthracene derivatives; carbodiimide derivatives; quinoxaline derivatives; pyridoindole derivatives; phenanthroline derivatives; thiole derivatives, etc. These materials can be formed into films alone, or used as a single layer formed by mixing with other materials, or can be formed into a laminated structure of layers formed alone, a laminated structure of layers formed as a mixture, or a laminated structure of layers formed alone and layers formed as a mixture. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet.

[0100] The electron injection layer of the organic electroluminescent device of the present invention can be formed using known materials, such as alkali metal salts such as lithium fluoride and cesium fluoride; alkaline earth metal salts such as magnesium fluoride; metal complexes of hydroxyquinoline derivatives such as lithium hydroxyquinoline; and metal oxides such as aluminum oxide.

[0101] In the electron transport layer or the electron injection layer, materials generally used for the layer and further N-doped with a metal such as cesium, a triarylphosphine oxide derivative, or the like can be used.

[0102] As the cathode of the organic electroluminescent device of the present invention, it is preferred to use an electrode material with a low work function (such as aluminum, magnesium) or an alloy with a low work function (such as magnesium-silver alloy, magnesium-indium alloy, aluminum-magnesium alloy) as the electrode material.

[0103] As the substrate of the present invention, a conventional substrate of an organic light emitting device, such as glass or plastic, can be used. In the present invention, a glass substrate is selected.

[0104] The present invention is further described below with reference to specific examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit its scope. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the manufacturer's recommendations. Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0105] Example 1: Synthesis of Intermediate 1

[0106]

[0107] Step 1: Dissolve reactant 1, 2-bromo-3-chloro-5-iodophenol (50 g, 149.88 mmol), in 300 ml of dichloromethane. Cool to 0°C, add imidazole (13.27 g, 194.99 mmol) and stir for 20 min. Then, add triisopropylsilyl chloride (29.50 g, 152.99 mmol) in portions and stir at 0°C for 30 min and at room temperature for 4 h. The reaction system was diluted with dichloromethane (220 ml), and the organic phase was washed three times with water (300 ml x 3). The organic phase was concentrated under reduced pressure at low temperature to obtain a residue. The residue was purified by silica gel column chromatography (petroleum ether:ethyl acetate = 0-100%) to obtain 65 g of the product from Step 1, with a yield of 88.49%. MS-ESI calculated value [M+H] + 490.69, the actual measured value is 490.69.

[0108] Step 2: The product of step 1 (65 g, 132.74 mmol), reactant 2, namely 2-methyl phenol formate (26.28 g, 146.01 mmol), potassium carbonate (45.86 g, 331.84 mmol), 300 ml of 1,4-dioxane, and 150 ml of water were stirred and dissolved, and the nitrogen was replaced three times. Then, the catalyst Pd(PPh3)4 (0.767 g, 0.664 mmol) was added, and the nitrogen was replaced three times. The temperature was raised to 40°C and the reaction was reacted for 5 hours. The temperature was lowered and the reaction system was concentrated under reduced pressure to obtain a residue. The residue was dissolved and extracted with water and dichloromethane, and the organic phase was separated. The organic phase was concentrated and loaded and purified by silica gel column chromatography (petroleum ether: ethyl acetate = 0-100%) to obtain step 2 product: 50 g, yield

[0109] Efficiency: 75.65%. MS-ESI calculated value [M+H] + 498.93, the measured value is 498.93.

[0110] Step 3: Dissolve the product from step 2 (50 g, 100.42 mmol) in 100 ml of concentrated sulfuric acid and heat to 75°C. After 5 h, slowly pour the reaction solution into water to quench the reaction. The precipitated yellow solid was allowed to stand and filtered to obtain a crude product. Add 100 ml of ethyl acetate, slurry, filter, and dry to obtain 30 g of the product from step 3, yield: 64.13%. MS-ESI calculated value [M+H] + 466.89, the measured value is 466.89.

[0111] Step 4: The product of step 3 (30 g, 64.39 mmol), reactant 3, namely 2-fluoro-3-methylphenylboronic acid (12.04 g, 70.83 mmol), potassium carbonate (22.25 g, 160.98 mmol), 1,4-dioxane 160 ml, and 80 ml of water were stirred and mixed to dissolve, and then nitrogen was replaced three times. Then, catalyst Pd(PPh3)4 (0.372 g, 0.322 mmol) was added, and nitrogen was replaced three times. The temperature was raised to 85 ° C and the reaction was reacted for 5 hours. The temperature was lowered and the reaction system was concentrated under reduced pressure to obtain a residue. The residue was dissolved and extracted with water and dichloromethane, and the organic phase was separated. The organic phase was concentrated and loaded and purified by silica gel column chromatography (petroleum ether: ethyl acetate = 0-100%) to obtain step 4 product: 27.5 g, yield

[0112] Rate: 83.56%. MS-ESI calculated value [M+H] + 512.11, the actual measured value is 512.11.

[0113] Step 5: The product from step 4 (27.50 g, 53.80 mmol) was dissolved in tetrahydrofuran (100 ml). The mixture was cooled to 0°C and stirred for 10 min. 80.7 ml of TBAF solution (1 M in THF) was slowly added dropwise to the reaction mixture, stirred for 0.5 h, returned to room temperature, and stirred for 5 h. The mixture was then concentrated under reduced pressure to obtain a residue. The residue was extracted with water and dichloromethane, and the organic phase was separated. The organic phase was concentrated and purified by silica gel column chromatography (petroleum ether:ethyl acetate = 0-100%) to obtain 17 g of the product from step 5, with a yield of 89.06%. MS-ESI calculated value [M+H] + 355.76, the measured value is 355.76.

[0114] Step 6: Dissolve the product from step 5 (17 g, 47.92 mmol) in DMF (100 ml), add powdered potassium carbonate (12.25 g, 95.84 mmol), and heat to 135°C, reflux, and stir for 5 h. Concentrate under reduced pressure to obtain a residue. The residue is extracted with water and dichloromethane, and the organic phase is separated. The organic phase is concentrated and purified by silica gel column chromatography (petroleum ether:ethyl acetate = 0-100%) to obtain 12 g of the product from step 6, in a yield of 74.81%. MS-ESI calculated value [M+H] + 335.75, the measured value is 335.75.

[0115] Step 7: In a 500 mL three-necked flask equipped with a reflux condenser and a dropping funnel, add 3.59 g (14.15 mmol) of iodine and 250 mL of glacial acetic acid under nitrogen protection, stir to dissolve, then add hypophosphorous acid (about 9 g, 70.5 mmol), heat to 120 ° C and react until the color of the system fades. The product from step 6 (12 g, 35.85 mmol) was then added all at once. Reflux was continued for 4 h, and the mixture was cooled to room temperature and poured into water to precipitate a large amount of white solid. This solid was filtered, washed, and dried to obtain a white solid. This solid was dissolved in tetrahydrofuran (100 ml), cooled to 0°C, and powdered sodium tert-butoxide (10.34 g, 107.54 mmol) was added. The temperature was maintained for 1 h, and then reactant 4, iodomethane (11.7 g, 82.45 mmol), was added dropwise. After the addition was complete, the mixture was stirred for 5 h and concentrated under reduced pressure to obtain a residue. The residue was dissolved and extracted with water and dichloromethane. The organic phase was separated and concentrated, and the organic phase was purified by silica gel column chromatography (petroleum ether:ethyl acetate = 0-100%) to obtain 10.8 g of the product from step 7 (yield: 86.42%). MS-ESI calculated value [M+H] + 349.83, the measured value is 349.83.

[0116] Step 8: Dissolve the product from Step 7 (10.8 g, 30.96 mmol) in dichloromethane (100 ml), cool to 0°C, and add boron tribromide (11.64 g, 46.44 mmol) dropwise. After complete addition, incubate for 0.5 h, return to room temperature, and continue stirring for 5 h. Quench with ice water, dissolve in dichloromethane, extract, and separate the organic phase. The organic phase is concentrated and purified by silica gel column chromatography (petroleum ether:ethyl acetate = 0-100%) to obtain 9 g of the product from Step 8, in a yield of 86.82%. MS-ESI calculated value [M+H] + 335.80, the actual measured value is 335.80.

[0117] Step 9: Dissolve the product from Step 8 (9 g, 26.88 mmol) in dichloromethane (100 ml), cool to 0°C, add triethylamine (5.45 g, 53.77 mmol), and dropwise add trifluoromethanesulfonic anhydride (9.10 g, 32.26 mmol). After the addition is complete, incubate for 0.5 h. Return to room temperature and continue stirring for 5 h. Quench with ice water, dissolve and extract with dichloromethane, separate the layers to obtain the organic phase, concentrate the organic phase, and purify it by silica gel column chromatography (petroleum ether:ethyl acetate = 0-100%) to obtain 10.8 g of the product from Step 9, intermediate 1, in a yield of 86.06%. MS-ESI calculated value [M+H] + 467.86, the measured value is 467.86.

[0118] Example 2-12

[0119] Referring to the synthetic route in Example 1, and selecting the corresponding reactants 1, 2, 3, and 4, a series of specific compounds of the present invention (see Table 1) were prepared respectively, wherein some intermediates did not contain the Otf structure, and the process proceeded to step 6.

[0120] Table 1

[0121]

[0122]

[0123] The total yield and mass spectrum of the target product are shown in Table 2 below:

[0124] Table 2

[0125]

[0126]

[0127] Final product preparation scheme:

[0128] Prepare the molecule as follows:

[0129]

[0130] Example 13

[0131] BH8 synthesis scheme:

[0132]

[0133] Step 1: Intermediate 1 (10 g, 21.42 mmol), reactant 5 (phenylboronic acid (3.13 g, 25.70 mmol), potassium carbonate (8.88 g, 64.26 mmol), 60 mL of 1,4-dioxane, and 30 mL of water were stirred and dissolved. The atmosphere was purged with nitrogen three times. Catalyst Pd(PPh3)4 (0.124 g, 0.107 mmol) was added. After purging with nitrogen three times, the temperature was raised to 85°C and the reaction mixture was reacted for 5 h. The reaction mixture was cooled and concentrated under reduced pressure to obtain a residue. The residue was dissolved and extracted with water and dichloromethane. The organic phase was separated and concentrated. The organic phase was purified by silica gel column chromatography (petroleum ether:ethyl acetate = 0-100%) to obtain 7.50 g of the product in Step 1, with a yield of 88.67%. MS-ESI calculated value [M+H] + 395.90, the actual measured value is 395.90.

[0134]

[0135] Step 2: The product from Step 1 (7.5 g, 18.99 mmol), reactant 6, d5-phenylanthraceneboronic acid (7.2 g, 23.74 mmol), anhydrous potassium phosphate (8.88 g, 64.26 mmol), and 60 ml of 1,4-dioxane were stirred and dissolved. The atmosphere was purged with nitrogen three times, and then catalyst Pd(OAc)2 (42.64 mg, 0.190 mmol) and sphos (0.39 g, 0.95 mmol) were added. The atmosphere was purged with nitrogen three times, and the temperature was raised to 85°C for 5 h. The reaction system was cooled and concentrated under reduced pressure to obtain a residue. The residue was dissolved and extracted with water and dichloromethane. The organic phase was separated and concentrated, and the organic phase was purified by silica gel column chromatography (petroleum ether:ethyl acetate = 0-100%) to obtain 9.50 g of BH8 in a yield of 80.97%. MS-ESI calculated value [M+H] + 618.80, the actual measured value is 618.80.

[0136] Examples 14-26

[0137] Referring to the synthetic route and scheme in Example 13, and selecting the corresponding reactants 5 and 6, a series of specific compounds of the present invention were prepared (see Table 3). Some intermediates did not contain the Otf structure and thus the synthesis of Step 1 was omitted.

[0138] Table 3

[0139]

[0140]

[0141]

[0142] The yield and mass spectrum of the target product are shown in Table 4 below:

[0143] Table 4

[0144]

[0145]

[0146]

[0147] Example 27: Synthesis of BH118

[0148] Compound BH19 (5 g, 8.1 mmol), 10% palladium on carbon (0.2 g), and deuterated water (150 mL) were added to a 300 mL autoclave and heated to 240°C for 12 h. The reaction system was cooled to room temperature, the organic phase was concentrated, the deuterated water was recovered, and the concentrated solid was purified by silica gel column chromatography (petroleum ether:ethyl acetate = 0-100%) to give 4.5 g of the product, in a yield of 90.01%. MS-ESI analysis value [M+H] + It is 634.25, compared with the BH2 molecular weight of 612.25, with 22 deuterium substitutions and a deuteration rate of 68.75%.

[0149] Examples 28-30

[0150] Referring to the synthesis scheme in Example 27, and selecting corresponding reactants, a series of specific compounds of the present invention were prepared (see Table 5).

[0151] Table 5

[0152]

[0153] Device Example 1: Preparation of Organic Electroluminescent Device 1 (Organic EL Device 1)

[0154] A hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light emitting layer 6, an electron transport layer 8, an electron injection layer 9 and a cathode 10 are sequentially formed on a transparent anode 2 (which is pre-formed on a glass substrate 1) to prepare a Figure 1 The organic electroluminescent device shown (but without the hole blocking layer 7).

[0155] Specifically, a glass substrate with an ITO electrode having a thickness of 100 nm was ultrasonically treated in a Decon 90 alkaline cleaning solution, rinsed in deionized water, cleaned three times in acetone and ethanol, baked in a clean environment until the water was completely removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam. The glass substrate with the ITO electrode was placed in a vacuum chamber and evacuated to 4×10 -4 -2×10 -5 Pa. On the above-mentioned ITO anode, 97wt% HIL / 3wt% HTL was evaporated to form a layer with a thickness of 10nm as a hole injection layer. On the above-mentioned hole injection layer, HTL was evaporated to form a layer with a thickness of 20nm as a hole transport layer. On the above-mentioned hole transport layer, EBL was evaporated to form a layer with a thickness of 10nm as an electron blocking layer. On the above-mentioned electron blocking layer, compound BH8 in Example 13 as a host material and BD1 as a dopant material were co-evaporated by dual sources to form a layer with a thickness of 25nm as a light-emitting layer. The doping weight ratio of BD1 was 3wt%. On the above-mentioned light-emitting layer, 50wt% ETL / 50wt% Liq was evaporated to form a layer with a thickness of 30nm as an electron transport layer. On the above-mentioned electron transport layer, Yb was evaporated to form a layer with a thickness of 1nm as an electron injection layer. On the electron injection layer, a 90wt% Mg / 10wt% Ag electrode was evaporated to a thickness of 15nm. Finally, CPL was evaporated on the Mg:Ag cathode to form a covering layer with a thickness of 65nm, thereby obtaining an organic EL device 1.

[0156] Device Example 2-18: Preparation of Organic EL Device 2-18

[0157] Referring to the preparation conditions of the organic EL device 1 in Example 31, and using the compounds corresponding to the structures of each layer, organic EL devices 2 to 18 were prepared respectively.

[0158] Comparative Examples 1-6: Preparation of Single-layer Organic EL Devices Comparative Examples 1-6

[0159] Referring to the preparation conditions of the organic EL device 1 in Device Example 1, and using the compounds corresponding to the layer structures in Table 6, organic EL device Comparative Examples 1-6 were prepared respectively.

[0160] Table 6

[0161]

[0162]

[0163] The organic EL devices in Table 6 use the fluorenfuran compounds of the present invention as the blue light host material of the light-emitting layer, and are matched with the blue light guest material BD1, while the comparative examples of the organic EL devices use DBH1, DBH2 containing naphthofuran anthracene groups, dibenzofuran monosubstituted with naphthalene anthracene DBH3, and dibenzofuran monosubstituted with anthracene groups DBH4, as well as fluorenfuran structure DBH5 and anthracene-substituted fluorene DBH6 used in the existing market as the blue light host material of the light-emitting layer, and the same blue light guest.

[0164] The structures of the compounds involved in the organic EL device and the comparative example of the organic EL device are as follows:

[0165]

[0166] The luminescence characteristics of the organic EL devices 1-18 prepared in Examples 1-18 and the organic EL devices 1-12 prepared in Comparative Examples 1-12 were measured under a DC voltage applied in ambient air at room temperature. The current-luminance-voltage characteristics of the devices were measured using a Keithley source-measurement system (Keithley 2400 Sourcemeter, Keithley 2000 Currentmeter) equipped with a calibrated silicon photodiode. The electroluminescence spectra were measured using a Photo Research PR655 spectrometer. The external quantum efficiency of the devices was calculated using the method described in Adv. Mater., 2003, 15, 1043-1048. The measurement results are shown in Table 7.

[0167] Table 7

[0168]

[0169] As shown in Table 7, in terms of efficiency and lifespan, single-layer organic EL devices made from the compounds of the present invention exhibit lower voltage, higher efficiency, and longer lifespan than devices composed of existing commercial materials DBH1-DBH4, indicating that devices using the compounds of the present invention as blue light-emitting host materials generally have superior performance. The main reason is that the fluorenylbenzofuran structure introduces a fluorene group, compared to a simple dibenzofuran structure. Fluorene has a bridged biphenyl structure, which has high thermal stability, high chemical stability, and high carrier transport properties. More importantly, it has suitable singlet and triplet states, molecular orbital energy levels, and high luminescence quantum efficiency. Therefore, its introduction into molecules with electroluminescent properties is beneficial to improving the stability and luminous efficiency of the device and reducing the device driving voltage.

[0170] At the same time, compared with devices composed of DBH5 with a similar structure, it shows better performance. The main reason is that compared with the DBH5 structure, the anthracene ring in this article is opposite to the fluorene methyl group, which has the advantage of reducing intermolecular vibration, reducing energy loss, and improving energy transmission efficiency. It also increases steric hindrance, reduces intermolecular stacking, and avoids the reduction in quantum efficiency caused by stacking. In addition, the different sites where the phenyl group is introduced also make the performance of various aspects different. For example, BH19 has more advantages than other sites, which can explain the difference in this aspect.

[0171] Compared with the device structure composed of pure fluorene DBH6, it also shows higher performance. The reason is that the introduced dibenzofuran structure can better disperse energy and the special structure of furan can form spatial polar repulsion with the existing doping material BD, further reducing the occurrence of stacking reaction.

[0172] Comparing compounds BH118, BH121, BH122, and BH125 with BH19, BH55, BH67, and BH79, it was found that the devices corresponding to the fluorenyldibenzofuran compounds of the present invention containing deuterium atoms had improved efficiency and longer device life than those corresponding to the compounds without deuterium atoms. This may be because the CD bond is more stable than the CH bond.

[0173] In addition, from Figure 2 The results shown in FIG2 show that when the dibenzofuran compound of the present invention is used as the main material of the light-emitting layer in the device, the luminescence pattern of the device is not affected, indicating that energy can be completely transferred to the light-emitting material in the device.

[0174] As can be seen from the above, the fluorenedibenzofuran compounds of the present invention can effectively reduce the operating voltage, improve the external quantum efficiency and extend the device life compared to the commonly used blue light host materials in the prior art.

[0175] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A fluorenylbenzofuran compound having a structure represented by formula (I): in, Ar1 is selected from substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl; R1 and R2 are the same or different and are independently selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C2-C30 heteroaryl; R3-R7 are the same or different and are independently selected from hydrogen, deuterium, tritium, halogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl; or two adjacent R3 are linked together to form a substituted or unsubstituted ring, or two adjacent R4 are linked together to form a substituted or unsubstituted ring; L1-L2 are the same or different and are independently selected from a single bond, or a substituted or unsubstituted C6-C30 arylene group, or a substituted or unsubstituted C2-C30 heteroarylene group; n is the same or different and is independently selected from 0, 1, 2, 3 or 4.

2. The fluorenylbenzofuran compound according to claim 1, characterized in that The Ar1 is selected from substituted or unsubstituted phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthrenyl, triphenylene, pyrenyl, dibenzofuranyl, dibenzothienyl, 9-phenylcarbazolyl, 9-biphenylcarbazolyl, and 9-naphthylcarbazolyl.

3. The fluorenobenzofuran compound according to claim 1, characterized in that Said R1 and R2 are the same or different and are independently selected from substituted or unsubstituted: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, phenyl, biphenyl and naphthyl.

4. The fluorenobenzofuran compound according to claim 1, characterized in that The R3-R7 are the same or different and are independently selected from hydrogen, deuterium, tritium, halogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C6-C14 aryl, substituted or unsubstituted C2-C12 heteroaryl; or two adjacent R3 are connected together to form a substituted or unsubstituted C6-C10 aromatic ring, or two adjacent R4 are connected together to form a substituted or unsubstituted C6-C10 aromatic ring.

5. The fluorenolbenzofuran compound according to claim 1, characterized in that: The L1-L2 are the same or different, and are independently selected from a single bond, or substituted or unsubstituted: phenylene, biphenylene, naphthylene, pyridylene, pyrimidylene.

6. The fluorenobenzofuran compound according to claim 1, characterized in that The fluorenylbenzofuran compound has a structure represented by any one of formula (I-1) to formula (I-6): wherein Ar2 and Ar3 are the same or different and are independently selected from substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl; Ring A is selected from C6-C10 aromatic rings substituted or unsubstituted by one or more R3; Ring B is selected from C6-C10 aromatic rings substituted or unsubstituted by one or more R4; n1 is the same or different and is independently selected from 0, 1, 2 or 3; n2 is the same or different and is independently selected from 0, 1, 2 or 3.

7. The fluorenobenzofuran compound according to claim 6, characterized in that: The Ar2 and Ar3 are the same or different and are independently selected from the group consisting of substituted or unsubstituted phenyl, biphenyl, terphenyl, pyridyl, pyrimidinyl, naphthyl, anthracenyl, phenanthrenyl, triphenylene, pyrene, dibenzofuranyl, dibenzothienyl, 9-phenylcarbazolyl, 9-biphenylcarbazolyl, and 9-naphthylcarbazolyl; the ring A is selected from the group consisting of benzene ring and naphthalene ring, which are substituted or unsubstituted with one or more R3; and the ring B is selected from the group consisting of benzene ring and naphthalene ring, which are substituted or unsubstituted with one or more R4.

8. The fluorenylbenzofuran compound according to claim 1, characterized in that: The deuteration rate of the fluorenylbenzofuran compound is 1-99%.

9. The fluorenolbenzofuran compound according to claim 1, characterized in that: The fluorenylbenzofuran compound is selected from:

10. A light-emitting device comprising a first electrode, a second electrode opposite to the first electrode, and at least one organic layer sandwiched between the first electrode and the second electrode, wherein the at least one organic layer comprises the fluorenylbenzofuran compound according to any one of claims 1 to 9.

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