CN111196822A

CN111196822A - Compound containing silicon fluorenyl and fluorenyl structures and electroluminescent device containing compound

Info

Publication number: CN111196822A
Application number: CN201811382861.5A
Authority: CN
Inventors: 马仲勋; 张麟; 邝志远; 夏传军
Original assignee: Beijing Summer Sprout Technology Co Ltd
Current assignee: Beijing Summer Sprout Technology Co Ltd
Priority date: 2018-11-20
Filing date: 2018-11-20
Publication date: 2020-05-26
Anticipated expiration: 2038-11-20
Also published as: CN111196822B

Abstract

A novel compound containing silicon fluorenyl and fluorenyl structures is disclosed. The compound is a triarylamine compound containing silicon fluorenyl and fluorenyl simultaneously, and can be used as a hole transport material and an electron blocking material in an electroluminescent device. These novel compounds provide better device integration. An electroluminescent device comprising the compound and a compound formulation are also disclosed.

Description

Compound containing silicon fluorenyl and fluorenyl structures and electroluminescent device containing compound

Technical Field

The present invention relates to compounds for use in organic electronic devices, such as organic light emitting devices. More particularly, it relates to a novel silafluorene-and-fluorene-containing compound, and an electroluminescent device and compound formulation comprising the same.

Background

Organic electronic devices include, but are not limited to, the following classes: organic Light Emitting Diodes (OLEDs), organic field effect transistors (O-FETs), Organic Light Emitting Transistors (OLETs), Organic Photovoltaics (OPVs), dye-sensitized solar cells (DSSCs), organic optical detectors, organic photoreceptors, organic field effect devices (OFQDs), light emitting electrochemical cells (LECs), organic laser diodes, and organic plasma light emitting devices.

In 1987, Tang and Van Slyke of Islamic Kodak reported a two-layer organic electroluminescent device comprising an arylamine hole transport layer and a tris-8-hydroxyquinoline-aluminum layer as an electron transport layer and a light-emitting layer (Applied Physics letters, 1987,51(12): 913-915). Upon biasing the device, green light is emitted from the device. The invention lays a foundation for the development of modern Organic Light Emitting Diodes (OLEDs). The most advanced OLEDs may comprise multiple layers, such as charge injection and transport layers, charge and exciton blocking layers, and one or more light emitting layers between the cathode and anode. Since OLEDs are a self-emissive solid state device, it offers great potential for display and lighting applications. Furthermore, the inherent properties of organic materials, such as their flexibility, may make them well suited for particular applications, such as in the fabrication of flexible substrates.

OLEDs can be classified into three different types according to their light emitting mechanisms. The OLEDs invented by Tang and van Slyke are fluorescent OLEDs. It uses only singlet luminescence. The triplet states generated in the device are wasted through the non-radiative decay channel. Therefore, the Internal Quantum Efficiency (IQE) of fluorescent OLEDs is only 25%. This limitation hinders the commercialization of OLEDs. In 1997, Forrest and Thompson reported phosphorescent OLEDs, which use triplet emission from complex-containing heavy metals as emitters. Thus, singlet and triplet states can be harvested, achieving 100% IQE. Due to its high efficiency, the discovery and development of phosphorescent OLEDs directly contributes to the commercialization of active matrix OLEDs (amoleds). Recently, Adachi has achieved high efficiency through Thermally Activated Delayed Fluorescence (TADF) of organic compounds. These emitters have a small singlet-triplet gap, making it possible for excitons to return from the triplet state to the singlet state. In TADF devices, triplet excitons are able to generate singlet excitons through reverse intersystem crossing, resulting in high IQE.

OLEDs can also be classified into small molecule and polymer OLEDs depending on the form of the material used. Small molecule refers to any organic or organometallic material that is not a polymer. The molecular weight of small molecules can be large, as long as they have a precise structure. Dendrimers with well-defined structures are considered small molecules. The polymeric OLED comprises a conjugated polymer and a non-conjugated polymer having a pendant light-emitting group. Small molecule OLEDs can become polymer OLEDs if post-polymerization occurs during the fabrication process.

Various OLED manufacturing methods exist. Small molecule OLEDs are typically fabricated by vacuum thermal evaporation. Polymer OLEDs are fabricated by solution processes such as spin coating, ink jet printing and nozzle printing. Small molecule OLEDs can also be made by solution processes if the material can be dissolved or dispersed in a solvent.

The light emitting color of the OLED can be realized by the structural design of the light emitting material. An OLED may comprise one light emitting layer or a plurality of light emitting layers to achieve a desired spectrum. Green, yellow and red OLEDs, phosphorescent materials have been successfully commercialized. Blue phosphorescent devices still have the problems of blue unsaturation, short device lifetime, high operating voltage, and the like. Commercial full-color OLED displays typically employ a hybrid strategy, using either blue fluorescence and phosphorescent yellow, or red and green. At present, the rapid decrease in efficiency of phosphorescent OLEDs at high luminance is still a problem. In addition, it is desirable to have a more saturated emission spectrum, higher efficiency and longer device lifetime.

The performances of the OLED device such as efficiency, service life and the like have important relation with the balance of the carrier concentration of the light emitting layer, and the balance of the carrier concentration of the light emitting layer can be more reasonably regulated and controlled through the molecular structure design of the charge transmission material and the carrier blocking material. Triarylamine can be used as a hole transport material and an electron blocking material in an electroluminescent device, silafluorene has unique properties due to the existence of silicon atoms, fluorenyl also has a unique structure, and the application of a derivative containing the triarylamine and the fluorenyl in an OLED material is not fully developed. The invention discloses a novel triarylamine compound containing silicon fluorenyl and fluorenyl, which can provide better comprehensive performance of devices.

Disclosure of Invention

The invention aims to provide a series of triarylamine compounds containing silicon fluorene and fluorenyl to solve at least part of the problems. The compounds are useful as hole transport materials and electron blocking materials in electroluminescent devices. Due to the unique structure of the compound, better comprehensive performance of the device can be provided.

According to one embodiment of the present invention, a compound having the structure of formula 1 is disclosed:

wherein

X₁To X₆Each is independently selected from CH, CD or N;

R₁and R₂Each independently selected from the group consisting of: hydrogen, deuterium, halogen, substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 ring carbon atoms, substituted or unsubstituted heteroalkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted aralkyl groups having 7 to 30 carbon atoms, substituted or unsubstituted alkoxy groups having 1 to 20 carbon atoms, substituted or unsubstituted aryloxy groups having 6 to 30 carbon atoms, substituted or unsubstituted alkenyl groups having 2 to 20 carbon atoms, substituted or unsubstituted aryl groups having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl groups having 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl groups having 3 to 20 carbon atoms, substituted or unsubstituted arylsilyl groups having 6 to 20 carbon atoms, substituted or unsubstituted amine groups having 0 to 20 carbon atoms, acyl groups, carbonyl groups, carboxylic acid groups, ester groups, nitriles, isonitriles, thio groups, sulfinyl groups, sulfonyl groups, phosphino groups, and combinations thereof;

X_aand X_bOne of them must be CR, X_aAnd X_bIs selected from CH, CD, or N;

wherein R is a structure represented by formula 2:

wherein

R₃And R₄Each independently selected from the group consisting of: hydrogen, deuterium, substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 ring carbon atoms, and combinations thereof;

wherein Ar is a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 60 carbon atoms, and combinations thereof;

R₁and R₂，R₃And R₄Can optionally be linked to form a ring.

According to another embodiment of the present invention, there is also disclosed an electroluminescent device comprising an anode, a cathode and an organic layer disposed between the anode and the cathode, the organic layer comprising the compound having formula 1.

According to another embodiment of the present invention, there is also disclosed a compound formulation comprising the compound having formula 1.

The triarylamine compound containing silicon fluorene and fluorene can be used as a hole transport material and an electron blocking material in an electroluminescent device. Due to the unique structure of the novel compounds, the novel compounds can effectively help the balance of hole and electron transport of the device so as to provide better comprehensive performance of the device.

Drawings

FIG. 1 is a schematic representation of an organic light emitting device that can contain a compound or compound formulation disclosed herein.

Fig. 2 is a schematic view of another organic light emitting device that may contain a compound or compound formulation disclosed herein.

Figure 3 is structural formula 1 showing compounds as disclosed herein.

Detailed Description

OLEDs can be fabricated on a variety of substrates, such as glass, plastic, and metal. Fig. 1 schematically, but without limitation, illustrates an organic light emitting device 100. The figures are not necessarily to scale, and some of the layer structures in the figures may be omitted as desired. The device 100 may include a substrate 101, an anode 110, a hole injection layer 120, a hole transport layer 130, an electron blocking layer 140, an emissive layer 150, a hole blocking layer 160, an electron transport layer 170, an electron injection layer 180, and a cathode 190. The device 100 may be fabricated by sequentially depositing the described layers. The nature and function of the layers, as well as exemplary materials, are described in more detail in U.S. patent US7,279,704B2, columns 6-10, which is incorporated herein by reference in its entirety.

There are more instances of each of these layers. For example, a flexible and transparent substrate-anode combination is disclosed in U.S. Pat. No. 5,844,363, which is incorporated by reference in its entirety. An example of a p-doped hole transport layer is doped with F at a molar ratio of 50:1₄TCNQ m-MTDATA as disclosed in U.S. patent application publication No. 2003/0230980, which is incorporated by reference in its entirety. Examples of host materials are disclosed in U.S. patent No. 6,303,238 to Thompson et al, which is incorporated by reference in its entirety. An example of an n-doped electron transport layer is BPhen doped with Li at a molar ratio of 1:1, as disclosed in U.S. patent application publication No. 2003/0230980, which is incorporated by reference in its entirety. U.S. Pat. Nos. 5,703,436 and 5,707,745, which are incorporated by reference in their entirety, disclose examples of cathodes including composite cathodes having a thin layer of a metal such as Mg: Ag and an overlying layer of transparent, conductive, sputter-deposited ITO. The principles and use of barrier layers are described in more detail in U.S. patent No. 6,097,147 and U.S. patent application publication No. 2003/0230980, which are incorporated by reference in their entirety. Examples of injection layers are provided in U.S. patent application publication No. 2004/0174116, which is incorporated by reference in its entirety. A description of the protective layer may be found in U.S. patent application publication No. 2004/0174116, which is incorporated by reference in its entirety.

The above-described hierarchical structure is provided via non-limiting embodiments. The function of the OLED may be achieved by combining the various layers described above, or some layers, such as the electron blocking layer, may be omitted entirely. It may also include other layers not explicitly described. Within each layer, a single material or a mixture of materials may be used to achieve optimal performance. Any functional layer may comprise several sub-layers. For example, the light emitting layer may have two layers of different light emitting materials to achieve a desired light emission spectrum; for another example, the hole transport layer may have a first hole transport layer and a second hole transport layer.

In one embodiment, an OLED may be described as having an "organic layer" disposed between a cathode and an anode. The organic layer may include one or more layers.

The OLED also requires an encapsulation layer, as shown in fig. 2, which is an exemplary, non-limiting illustration of an organic light emitting device 200, which differs from fig. 1 in that an encapsulation layer 102 may also be included over the cathode 190 to protect against harmful substances from the environment, such as moisture and oxygen. Any material capable of providing an encapsulation function may be used as the encapsulation layer, such as glass or a hybrid organic-inorganic layer. The encapsulation layer should be placed directly or indirectly outside the OLED device. Multilayer film encapsulation is described in U.S. patent US7,968,146B2, the entire contents of which are incorporated herein by reference.

Devices manufactured according to embodiments of the present invention may be incorporated into various consumer products having one or more electronic component modules (or units) of the device. Some examples of such consumer products include flat panel displays, monitors, medical monitors, televisions, billboards, lights for indoor or outdoor lighting and/or signaling, head-up displays, fully or partially transparent displays, flexible displays, smart phones, tablet computers, tablet handsets, wearable devices, smart watches, laptop computers, digital cameras, camcorders, viewfinders, micro-displays, 3-D displays, vehicle displays, and tail lights.

The materials and structures described herein may also be used in other organic electronic devices as previously listed.

As used herein, "top" means furthest from the substrate, and "bottom" means closest to the substrate. Where a first layer is described as being "disposed on" a second layer, the first layer is disposed farther from the substrate. Other layers may be present between the first and second layers, unless it is specified that the first layer is "in contact with" the second layer. For example, a cathode can be described as being "disposed on" an anode even though various organic layers are present between the cathode and the anode.

As used herein, "solution processable" means capable of being dissolved, dispersed or transported in and/or deposited from a liquid medium in the form of a solution or suspension.

A ligand may be referred to as "photoactive" when it is believed that the ligand directly contributes to the photoactive properties of the emissive material. A ligand may be referred to as "ancillary" when it is believed that the ligand does not contribute to the photoactive properties of the emissive material, but the ancillary ligand may alter the properties of the photoactive ligand.

It is believed that the Internal Quantum Efficiency (IQE) of fluorescent OLEDs can be limited by delaying fluorescence beyond 25% spin statistics. Delayed fluorescence can generally be divided into two types, i.e., P-type delayed fluorescence and E-type delayed fluorescence. P-type delayed fluorescence results from triplet-triplet annihilation (TTA).

On the other hand, E-type delayed fluorescence does not depend on collision of two triplet states, but on conversion between triplet and singlet excited states. Compounds capable of producing E-type delayed fluorescence need to have a very small mono-triplet gap in order to switch between energy states. Thermal energy can activate a transition from a triplet state back to a singlet state. This type of delayed fluorescence is also known as Thermally Activated Delayed Fluorescence (TADF). A significant feature of TADF is that the retardation component increases with increasing temperature. If the reverse intersystem crossing (IRISC) rate is fast enough to minimize non-radiative decay from the triplet state, then the fraction of the backfill singlet excited state may reach 75%. The total singlet fraction may be 100%, far exceeding 25% of the spin statistics of the electrogenerated excitons.

The delayed fluorescence characteristic of type E can be found in excited complex systems or in single compounds. Without being bound by theory, it is believed that E-type delayed fluorescence requires the light emitting material to have a small mono-triplet energy gap (Δ Ε)_S-T). Organic non-metal containing donor-acceptor emissive materials may be able to achieve this. The emission of these materials is generally characterized as donor-acceptor Charge Transfer (CT) type emission. Spatial separation of HOMO from LUMO in these donor-acceptor type compounds generally results in small Δ E_S-T. These states may include CT states. Generally, donor-acceptor light emitting materials are constructed by linking an electron donor moiety (e.g., an amino or carbazole derivative) to an electron acceptor moiety (e.g., a six-membered, N-containing, aromatic ring).

Definitions for substituent terms

Halogen or halide-as used herein, includes fluorine, chlorine, bromine and iodine.

Alkyl-comprises both straight and branched chain alkyl groups. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, neopentyl, 1-methylpentyl, 2-methylpentyl, 1-pentylhexyl, 1-butylpentyl, 1-heptyloctyl, 3-methylpentyl. In addition, the alkyl group may be optionally substituted. The carbons in the alkyl chain may be substituted with other heteroatoms. Among the above, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl and neopentyl are preferable.

Cycloalkyl-as used herein, comprises a cyclic alkyl group. Preferred cycloalkyl groups are those containing 4 to 10 ring carbon atoms and include cyclobutyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4, 4-dimethylcyclohexyl, 1-adamantyl, 2-adamantyl, 1-norbornyl, 2-norbornyl and the like. In addition, the cycloalkyl group may be optionally substituted. The carbon in the ring may be substituted with other heteroatoms.

Alkenyl-as used herein, encompasses both straight and branched chain olefinic groups. Preferred alkenyl groups are those containing 2 to 15 carbon atoms. Examples of the alkenyl group include a vinyl group, an allyl group, a 1-butenyl group, a 2-butenyl group, a 3-butenyl group, a1, 3-butadienyl group, a 1-methylvinyl group, a styryl group, a 2, 2-diphenylvinyl group, a 1-methylallyl group, a1, 1-dimethylallyl group, a 2-methylallyl group, a 1-phenylallyl group, a 3, 3-diphenylallyl group, a1, 2-dimethylallyl group, a 1-phenyl-1-butenyl group and a 3-phenyl-1-butenyl group. In addition, alkenyl groups may be optionally substituted.

Alkynyl-as used herein, straight and branched alkynyl groups are contemplated. Preferred alkynyl groups are those containing 2 to 15 carbon atoms. In addition, alkynyl groups may be optionally substituted.

Aryl or aromatic-as used herein, encompasses both non-fused and fused systems. Preferred aryl groups are those containing from 6 to 60 carbon atoms, more preferably from 6 to 30 carbon atoms, or from 6 to 20 carbon atoms, or from 6 to 12 carbon atoms. Examples of aryl groups include phenyl, biphenyl, terphenyl, triphenylene, tetraphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chicory, perylene and azulene, preferably phenyl, biphenyl, terphenyl, triphenylene, fluorene and naphthalene. In addition, the aryl group may be optionally substituted. Examples of non-fused aryl groups include phenyl, biphenyl-2-yl, biphenyl-3-yl, biphenyl-4-yl, p-terphenyl-4-yl, p-terphenyl-3-yl, p-triphenyl-2-yl, m-terphenyl-4-yl, m-terphenyl-3-yl, m-terphenyl-2-yl, o-tolyl, m-tolyl, p-tolyl, p- (2-phenylpropyl) phenyl, 4 '-methyldiphenyl, 4' -tert-butyl-p-terphenyl-4-yl, o-cumyl, m-cumyl, p-cumyl, 2, 3-xylyl, 3, 4-xylyl, 2, 5-xylyl, mesityl and m-quaterphenyl.

Heterocyclyl or heterocyclic-as used herein, encompasses aromatic and non-aromatic cyclic groups. Heteroaryl also refers to heteroaryl. Preferred non-aromatic heterocyclic groups are those containing 3 to 7 ring atoms, which include at least one heteroatom such as nitrogen, oxygen and sulfur. The heterocyclic group may also be an aromatic heterocyclic group having at least one hetero atom selected from a nitrogen atom, an oxygen atom, a sulfur atom and a selenium atom.

Heteroaryl-as used herein, encompasses non-fused and fused heteroaromatic groups that may contain 1 to 5 heteroatoms. Preferred heteroaryl groups are those containing from 3 to 60 carbon atoms, more preferably from 3 to 30 carbon atoms, or from 3 to 20 carbon atoms, or from 3 to 12 carbon atoms. Suitable heteroaryl groups include dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridine indole, pyrrolopyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, bisoxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, indoline, benzimidazole, indazole, indenozine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, benzothienopyridine, thienobipyridine, benzothiophenopyridine, cinnolinopyrimidine, selenobenzodipyridine, selenobenzene, preferably dibenzothiophene, dibenzofuran, dibenzoselenophene, carbazole, indolocarbazole, imidazole, pyridine, triazine, benzimidazole, 1, 2-azaborine, 1, 3-azaborine, 1, 4-azaborine, borazole, and aza analogues thereof. In addition, the heteroaryl group may be optionally substituted.

Alkoxy-is represented by-O-alkyl. Examples and preferred examples of the alkyl group are the same as those described above. Examples of the alkoxy group having 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms include methoxy, ethoxy, propoxy, butoxy, pentyloxy and hexyloxy. The alkoxy group having 3 or more carbon atoms may be linear, cyclic or branched.

Aryloxy-is represented by-O-aryl or-O-heteroaryl. Examples and preferred examples of aryl and heteroaryl groups are the same as described above. Examples of the aryloxy group having 6 to 40 carbon atoms include a phenoxy group and a biphenyloxy group.

Examples of the aralkyl group include benzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylisopropyl, 2-phenylisopropyl, α -naphthylmethyl, 1- α -naphthyl-ethyl, 2- α -naphthylethyl, 1- α -naphthylisopropyl, 2- α -naphthylisopropyl, β -naphthylmethyl, 1- β -naphthyl-ethyl, 2- β -naphthyl-ethyl, 1- β -naphthylisopropyl, 2- β -naphthylisopropyl, p-methylbenzyl, m-methylbenzyl, o-methylbenzyl, p-chlorobenzyl, m-chlorobenzyl, o-chlorobenzyl, p-bromobenzyl, m-bromobenzyl, o-bromobenzyl, p-iodobenzyl, m-iodobenzyl, p-hydroxybenzyl, m-hydroxybenzyl, o-hydroxybenzyl, p-aminobenzyl, m-aminobenzyl, p-nitrobenzyl, m-nitrobenzyl, p-cyanobenzyl, 1-cyanophenyl-isopropyl, 1- α -naphthylisopropyl, 2- β -naphthylisopropyl, p-methylbenzyl, p-chlorobenzyl, p-cyanobenzyl, o-cyanobenzyl, p-cyanobenzyl, o-cyanobenzyl, and p-cyanobenzyl.

The term "aza" in aza-dibenzofuran, aza-dibenzothiophene, etc., means that one or more C-H groups in the corresponding aromatic moiety are replaced by a nitrogen atom. For example, azatriphenylenes include dibenzo [ f, h ] quinoxalines, dibenzo [ f, h ] quinolines, and other analogs having two or more nitrogens in the ring system. Other nitrogen analogs of the above-described aza derivatives may be readily envisioned by one of ordinary skill in the art, and all such analogs are intended to be encompassed within the terms described herein.

The alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclyl, aryl, and heteroaryl groups may be unsubstituted or may be substituted with one or more groups selected from deuterium, halogen, alkyl, cycloalkyl, aralkyl, alkoxy, aryloxy, amino, cyclic amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.

It will be understood that when a molecular fragment is described as a substituent or otherwise attached to another moiety, its name may be written depending on whether it is a fragment (e.g., phenyl, phenylene, naphthyl, dibenzofuranyl) or depending on whether it is an entire molecule (e.g., benzene, naphthalene, dibenzofuran). As used herein, these different ways of specifying substituents or linking fragments are considered to be equivalent.

In the compounds mentioned in the present disclosure, a hydrogen atom may be partially or completely replaced by deuterium. Other atoms such as carbon and nitrogen may also be replaced by their other stable isotopes. Substitution of other stable isotopes in the compounds may be preferred because it enhances the efficiency and stability of the device.

In the compounds mentioned in the present disclosure, multi (multiple) substitution is meant to encompass bi (multiple) substitution up to the range of the maximum available substitutions.

In the compounds mentioned in the present disclosure, the expression that two adjacent substituents can optionally be linked to form a ring is intended to be taken to mean that the two groups are linked to each other by a chemical bond. This is exemplified by:

furthermore, the expression that two adjacent substituents can be optionally connected to form a ring is also intended to be taken to mean that, in the case where one of the two groups represents hydrogen, the second group is bonded at the position to which the hydrogen atom is bonded, thereby forming a ring. This is exemplified by:

according to one embodiment of the invention, there is disclosed a compound having formula 1:

wherein

X₁To X₆Each is independently selected from CH, CD or N;

r in formula 1₁And R₂Can optionally be linked to form a ring;

when X is present_aWhen it is CR, X_bIs CH, CD or N; or when X is_bWhen is CR, X_aIs CH, CD or N; wherein R is a structure represented by formula 2:

wherein

wherein Ar is selected from the group consisting of substituted or unsubstituted aryl groups having 6 to 60 carbon atoms, substituted or unsubstituted heteroaryl groups having 3 to 60 carbon atoms, and combinations thereof;

r in formula 2₃And R₄Can optionally be linked to form a ring.

According to one embodiment of the present invention, wherein X₁To X₆Each independently selected from CH or CD.

According to one embodiment of the present invention, wherein X₁To X₄One of which is N.

According to one embodiment of the present invention, wherein X₂Is N.

According to one embodiment of the present invention, wherein X₃Is N.

According to one embodiment of the present invention, wherein X_aIs CH or CD.

According to one embodiment of the present invention, wherein X_bIs CH or CD.

According to one embodiment of the invention, wherein R₁And R₂Each independently selected from substituted or unsubstituted aryl groups having 6 to 30 carbon atoms.

According to one embodiment of the invention, wherein R₁And R₂Is phenyl.

According toAn embodiment of the invention, wherein R₃And R₄Each independently selected from the group consisting of: hydrogen, deuterium, methyl, ethyl, cyclohexyl, cyclopentyl, and combinations thereof.

According to one embodiment of the invention, wherein Ar is selected from the group consisting of the following structures:

according to an embodiment of the present invention, wherein the compound is selected from the group consisting of compound 1 to compound 762, the specific structures of compound 1 to compound 762 are set forth in claim 8.

According to one embodiment of the present invention, wherein said compound 1 to compound 762 are capable of partial or complete deuteration.

According to another embodiment of the present invention, there is also disclosed an electroluminescent device including:

an anode, a cathode, a anode and a cathode,

a cathode electrode, which is provided with a cathode,

and an organic layer disposed between the anode and the cathode, the organic layer comprising the compound having the structure of formula 1, the compound having the structure of formula 1 being described in detail in any of the above examples.

According to one embodiment of the present invention, wherein the organic layer is a hole transport layer.

According to an embodiment of the present invention, wherein the hole transport layer is a second hole transport layer.

According to another embodiment of the invention, a compound formulation is also disclosed, comprising a compound having formula 1. The compound is described in detail in any of the above examples.

In combination with other materials

The materials described herein for use in particular layers in an organic light emitting device may be used in combination with various other materials present in the device. Combinations of these materials are described in detail in U.S. patent application Ser. No. 0132-0161 of U.S. 2016/0359122A1, the entire contents of which are incorporated herein by reference. The materials described or referenced therein are non-limiting examples of materials that may be used in combination with the compounds disclosed herein, and one skilled in the art can readily review the literature to identify other materials that may be used in combination.

Materials described herein as being useful for particular layers in an organic light emitting device can be used in combination with a variety of other materials present in the device. For example, the materials of the specific layers disclosed herein may be used in conjunction with a variety of light emitting, host, transport, barrier, injection, electrode, and other layers that may be present. Combinations of these materials are described in detail in paragraphs 0080-0101 of patent application US2015/0349273A1, which is incorporated herein by reference in its entirety. The materials described or referenced therein are non-limiting examples of materials that may be used in combination with the compounds disclosed herein, and one skilled in the art can readily review the literature to identify other materials that may be used in combination.

In the examples of material synthesis, all reactions were carried out under nitrogen unless otherwise stated. All reaction solvents were anhydrous and used as received from commercial sources. The synthesis product is subjected to structural validation and characterization using one or more equipment conventional in the art (including, but not limited to, Bruker's nuclear magnetic resonance apparatus, Shimadzu's liquid chromatograph-mass spectrometer, gas chromatograph-mass spectrometer, differential scanning calorimeter, Shanghai prism-based fluorescence spectrophotometer, Wuhan Corset's electrochemical workstation, Anhui Beidek's sublimator, etc.) in a manner well known to those skilled in the art. In an embodiment of the device, the device characteristics are also tested using equipment conventional in the art (including, but not limited to, an evaporator manufactured by Anttrom engineering, an optical test system manufactured by Fushida, Suzhou, an ellipsometer manufactured by Beijing Mass., etc.) in a manner well known to those skilled in the art. Since the relevant contents of the above-mentioned device usage, testing method, etc. are known to those skilled in the art, the inherent data of the sample can be obtained with certainty and without being affected, and therefore, the relevant contents are not described in detail in this patent.

Materials synthesis example:

the preparation method of the compound of the present invention is not limited, and the following compounds are typically but not limited to, and the synthetic route and the preparation method thereof are as follows:

1. synthesis of Compound 203

Step 1: synthesis of intermediate 1

2-aminobiphenyl (20g, 118.2mmol), 2-bromo-9, 9-dimethylfluorene (24.8g, 90.9mmol), sodium tert-butoxide (17.45g, 181.8mmol) and Pd₂(dba)₃(4.16g, 4.5mmol) was charged into a 1L three-necked flask, and degassed with nitrogen for 15 minutes. Toluene (400mL) and P (t-Bu) were added in this order₃(18.2g, 9mmol, 10% in toluene). The reaction mixture was heated to 95 ℃ and reacted for 1 hour. After the reaction is finished, cooling the reaction liquid to room temperature, adding water, separating liquid, extracting the water phase by using dichloromethane, combining organic phases, washing by using water, and removing the solvent in vacuum to obtain an oily crude product. The crude oil was purified by column chromatography to give crude yellow solid. The crude solid was recrystallized from ethanol to yield intermediate 1 as a white solid (25.2g, 76% yield).

Step 2: synthesis of intermediate 2

2-bromo-4-chloroiodobenzene (30.8g, 97.05mmol), 2-bromobenzeneboronic acid (21.44g, 106.76mmol), tetratriphenylphosphine palladium (4.48g, 3.88mmol) and sodium carbonate (20.6g, 194.1mmol) were charged in a 1L three-necked flask, toluene (200mL), ethanol (100mL) and water (100mL) were added, and after 15 minutes of degassing with nitrogen, the reaction was heated to reflux for overnight. And cooling the reaction solution to room temperature, adding water, separating liquid, extracting the water phase by using ethyl acetate, combining organic phases, and then washing by using brine. The solvent was removed in vacuo and the resulting residue was purified by column chromatography to give intermediate 2(30g, 89.2% yield) as a colorless liquid.

And step 3: synthesis of intermediate 3

Intermediate 2(25.1g, 72.45mmol) was dissolved in dry ether (200mL) and degassed with nitrogen for 15 min. The resulting solution was cooled to-70 ℃ or lower with a dry ice-acetone bath, and n-butyllithium (70mL, 173.88mmol, 2.5M n-hexane solution) was slowly added dropwise. After the dropwise addition of the n-butyllithium is finished, the reaction is kept at low temperature for 2 hours. A solution of diphenyldichlorosilane (27.5g, 108.7mmol) in THF (50mL) was added dropwise to the reaction at-70 ℃. The cold bath was then removed and the reaction allowed to spontaneously warm to room temperature and react at room temperature overnight. Carefully quenched with water, the aqueous phases extracted with dichloromethane, the organic phases combined and washed with water, the solvent removed in vacuo and the residue purified by column chromatography to afford intermediate 3(17g, 63% yield) as a white solid.

And 4, step 4: synthesis of Compound 203

Intermediate 1(17g, 47mmol), intermediate 3(20.8g, 56.4mmol), sodium tert-butoxide (9g, 94mmol) and Pd₂(dba)₃(2.15g, 2.35mmol) was charged into a 500mL three-necked flask, and degassed with nitrogen for 15 minutes. Toluene (250mL) and P (t-Bu) were added sequentially₃(9.5g, 4.7mmol, 10% in toluene). The reaction solution was heated to reflux for 8 hours. After the reaction is complete, the reaction mixture is cooled to room temperature, water is added, the phases are separated, the aqueous phase is extracted with dichloromethane, the organic phases are combined and washed with water, the solvent is removed in vacuo, and the residue is purified by column chromatography to give the crude white solid. The crude solid was recrystallized from acetone to yield compound 203 as a white solid (15g, 46% yield). The product was identified as the desired product, molecular weight 694.

Synthesis example 2: synthesis of Compound 201

Step 1: synthesis of intermediate 4

4-aminobiphenyl (50g, 295.9mmol), 2-bromo-9, 9-dimethylfluorene (80.8g, 295.9mmol), sodium tert-butoxide (56.8g, 591.8mmol) and Pd₂(dba)₃(13.5g, 14.8mmol) was charged into a 2L three-necked flask, and degassed with nitrogen for 15 minutes. Toluene (800mL) and P (t-Bu) were added sequentially₃(59.8g, 29.6mmol, 10% in toluene). The reaction mixture was heated to 95 ℃ and reacted for 1 hour. After the reaction is finished, cooling the reaction liquid to room temperature, adding water, separating liquid, extracting the water phase by using dichloromethane, combining organic phases, washing by using water, and removing the solvent in vacuum to obtain an oily crude product. The crude oil was purified by column chromatography to give crude yellow solid. The crude solid was recrystallized from ethanol to yield intermediate 4 as a white solid (92.9g, 87% yield).

Step 2: synthesis of Compound 201

Intermediate 4(30g, 83.1mmol), intermediate 3(30.7g, 83.1mmol), sodium tert-butoxide (16g, 166.2mmol) and palladium acetate (2.15g, 4.16mmol) were charged to a 500mL three-necked flask and degassed with nitrogen for 15 minutes. Toluene (250mL) and P (t-Bu) were added sequentially₃(16.8g, 8.32mmol, 10% in toluene). The reaction solution was heated to reflux for 8 hours. After the reaction is complete, the reaction mixture is cooled to room temperature, water is added, the phases are separated, the aqueous phase is extracted with dichloromethane, the organic phases are combined and washed with water, the solvent is removed in vacuo, and the residue is purified by column chromatography to give the crude white solid. The crude solid was recrystallized from acetone to yield compound 201 as a white solid (46.1g, yield 80%). The product was identified as the desired product, molecular weight 694.

It will be appreciated by those skilled in the art that the above-described preparation of the compounds is merely an illustrative example and that those skilled in the art will be able to modify it to obtain other compound structures of the invention.

Device example 1

First, a glass substrate, having an Indium Tin Oxide (ITO) anode 80nm thick, was cleaned and then treated with oxygen plasma and UV ozone. After treatment, the substrate was dried in a glove box to remove moisture. The substrate is then mounted on a substrate holder and loaded into a vacuum chamber. The organic layer specified below was in a vacuum of about 10 degrees^-8In the case of torr, the evaporation was carried out on the ITO anode in turn by thermal vacuum evaporation at a rate of 0.2-2 a/s. Compound HI was used as Hole Injection Layer (HIL). Compound HT was used as the first hole transport layer (HTL 1). Compound 203 synthesized according to synthesis example 1 was used as the second hole transport layer (HTL 2). Then compound GD doping was co-deposited in compounds H1 and H2 to serve as a light emitting layer (EML). H2 was used as a Hole Blocking Layer (HBL). On HBL, compound ET and 8-hydroxyquinoline-lithium (Liq) were co-deposited as an Electron Transport Layer (ETL). Finally, 8-hydroxyquinoline-lithium (Liq) was evaporated to a thickness of 1nm as an electron injection layer, and 120nm of aluminum as a cathode. The device was then transferred back to the glove box and encapsulated with a glass lid and moisture absorber to complete the device.

Device example 2

The same procedure as in the fabrication of device example 1 was conducted except that compound 201 synthesized in synthesis example 2 was used as the second hole transport layer (HTL 2).

Device comparative example 1

The same procedure as in the fabrication of device example 1 was followed except that compound H1 was used as the second hole transporting layer (HTL 2).

The detailed structure and thickness of the device layer portions are shown in the table below. Wherein more than one layer of the materials used is obtained by doping different compounds in the stated weight ratios.

Table 1 device structure of device embodiments

The material structure used in the device is as follows:

the IVL and lifetime characteristics of the device were measured. Table 2 shows the values at 1000cd/m²Next, measurement data of Luminous Efficiency (LE), Power Efficiency (PE), λ max, full width at half maximum (FWHM), voltage (V) and CIE.

TABLE 2 device data

Table 3 shows the data at 21750cd/m²Voltage (V), Power Efficiency (PE) and LT 97.

TABLE 3 device data

Discussion:

as can be seen from tables 2 and 3, example 1 has a narrower half-peak width, a lower voltage, and higher luminous efficiency and power efficiency than comparative example 1, and the lifetime LT97 of the device is improved by almost 39% relative to comparative example 1; example 2 has a narrower half-peak width, a lower voltage, and a higher power efficiency than comparative example 1 in the case where the device life and the light emission efficiency are substantially leveled with those of comparative example 1. The data presented in tables 2 and 3 indicate that the compounds of formula 1, characterized by containing silafluorene and fluorene, disclosed in the present invention, can effectively help balance the transport of holes and electrons in the device, concentrate the combination of holes and electrons in the appropriate position of the light-emitting layer, and can provide better overall performance in the device, such as better color purity, higher efficiency, lower operating voltage and long device lifetime.

It should be understood that the various embodiments described herein are illustrative only and are not intended to limit the scope of the invention. Thus, the invention as claimed may include variations from the specific embodiments and preferred embodiments described herein, as will be apparent to those skilled in the art. Many of the materials and structures described herein may be substituted with other materials and structures without departing from the spirit of the present invention. It should be understood that various theories as to why the invention works are not intended to be limiting.

Claims

1. A compound having formula 1:

wherein

X₁To X₆Each is independently selected from CH, CD or N;

X_aand X_bOne of them must be CR, X_aAnd X_bIs selected from CH, CD, or N;

wherein R is a structure represented by formula 2:

wherein

R₁and R₂，R₃And R₄Can optionally be linked to form a ring.

2. The compound of claim 1, wherein X₁To X₆Each independently selected from CH or CD.

3. The compound of claim 1, wherein X₁To X₄One of which is N; preferably, X₂Is N or X₃Is N.

4. The compound of claim 1, wherein X_aIs CH or CD; or X_bIs CH or CD.

5. The compound of claim 1, wherein R₁And R₂Each independently selected from substituted or unsubstituted aryl groups having 6 to 30 carbon atoms; preferably, R₁And R₂Is phenyl.

6. The compound of claim 1, wherein R₃And R₄Each independently selected from the group consisting of: hydrogen, deuterium, methyl, ethyl, cyclohexyl, cyclopentyl, and combinations thereof.

7. The compound of claim 1, wherein said Ar is selected from the group consisting of the following structures: