A compound containing a triarylamine and a phenanthrene structure and its application

Abstract

The present invention discloses a compound containing a triarylamine and a phenanthrene structure and its application, belonging to the field of semiconductor technology. The compound containing a triarylamine and a phenanthrene structure of the present invention has a structure as shown in the general formula (1). When it is applied to an organic electroluminescent device, it has strong hole injection and transport capabilities and appropriate energy levels. Holes can be effectively transported and injected into the light-emitting layer, and high-efficiency light emission under low driving voltage of the organic electroluminescent device can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to a compound containing a triarylamine and a phenanthrene structure and its application. Background Art

[0002] In an organic light-emitting diode (OLED), carriers (holes and electrons) are injected into the device from two electrodes of the device respectively under the drive of an electric field, and meet and recombine to emit light in the organic light-emitting layer. For a high-performance organic light-emitting diode, various organic functional materials are required to have good optoelectronic properties. For example, as a charge transport material, it is required to have good carrier mobility. In the existing organic light-emitting diodes, the injection and transport characteristics of the hole injection layer material and the hole transport layer material used are relatively weak, and the hole injection and transport rates do not match the electron injection and transport rates, resulting in a large offset of the recombination region, which is not conducive to the stability of the device. In addition, a reasonable energy level matching of the hole injection layer material and the hole transport layer material is an important factor for improving the device efficiency and device life. Therefore, how to adjust the balance between holes and electrons and adjust the recombination region has always been an important topic in this field.

[0003] Blue organic light-emitting diodes have always been the weak link in the development of full-color OLEDs. So far, the performance such as the efficiency and life of blue light devices has been difficult to be comprehensively improved. Therefore, how to improve the performance of such devices is still a crucial problem and challenge faced in this field. At present, most of the blue light host materials used in the market are electron-deficient hosts. Therefore, in order to adjust the carrier balance of the light-emitting layer, the hole transport material is required to have excellent hole transport performance. The better the hole injection and transport, the recombination region will shift away from the electron blocking layer side, so as to be away from the interface light emission, which improves the device performance and increases the life. Therefore, the hole transport region material is required to have high hole injectability, high hole mobility, high electron blocking property and high electron weather resistance.

[0004] Since the hole transport material has a relatively thick film thickness, the heat resistance and amorphousness of the material will have a crucial impact on the life of the device. Materials with poor heat resistance are prone to decomposition during the evaporation process, polluting the evaporation chamber and damaging the device life; materials with poor film phase stability will crystallize during the use of the device, reducing the device service life. Therefore, the hole transport material is required to have high film phase stability and decomposition temperature during use. However, the development of materials for stable and effective organic material layers used in organic light-emitting diodes has not been fully realized. Therefore, it is necessary to continuously develop a new material to better meet the performance requirements of organic light-emitting diodes. Summary of the Invention

[0005] In view of the above problems existing in the prior art, the applicant of the present invention provides a compound containing a triarylamine and a phenanthrene structure and its application. The compound of the present invention contains a phenanthryl group and a triarylamine structure, and has excellent hole transport ability, film phase stability and weather resistance. When using a triarylamine and a phenanthrene compound to form a hole injection and transport material for an organic electroluminescent device, an improvement in device performance can be shown, such as effects of improved device efficiency, reduced driving voltage and extended lifespan, etc.

[0006] The technical solution of the present invention is as follows:

[0007] A compound containing a triarylamine and a phenanthrene structure, the structure of the compound is shown in general formula (1):

[0008]

[0009] In general formula (1), L, L1, and L2 each independently represent a single bond, a phenylene group, a naphthylene group, a biphenylene group, a furylene group, a benzofurylene group or a dibenzofurylene group;

[0010] R1 and R2 each independently represent one of a substituted or unsubstituted C6-C 30 aryl group, a substituted or unsubstituted 5- to 30-membered heteroaryl group containing one or more heteroatoms;

[0011] R represents a phenyl group, a naphthyl group, a biphenyl group, a furyl group, a benzofuryl group or a dibenzofuryl group;

[0012] The substituents for the substituent groups are each independently selected from deuterium, tritium, C 1-10 alkyl group, a C6-C 30 aryl group, one or more of a 5- to 30-membered heteroaryl group containing one or more heteroatoms;

[0013] The heteroatom is an oxygen, sulfur or nitrogen atom.

[0014] In a preferred embodiment, R1 and R2 each independently represent one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted benzofuryl group, a substituted or unsubstituted dibenzofuryl group, a substituted or unsubstituted dimethylfluorenyl group, a substituted or unsubstituted diphenylfluorenyl group, a substituted or unsubstituted spirofluorene group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted benzodioxin, a substituted or unsubstituted acenaphthyl group, a substituted or unsubstituted piperonyl group, a substituted or unsubstituted indenyl group, a substituted or unsubstituted carbazolyl group;

[0015] The substituents for the substituent groups are one or more of deuterium, tritium, methyl, tert-butyl, adamantyl, phenyl, naphthyl, biphenyl, carbazolyl, benzofuryl, dibenzofuryl, fluorenyl, phenanthryl, pyrenyl, acenaphthyl, piperonyl.

[0016] In a preferred embodiment, R represents phenyl, and R2 represents biphenyl or phenyl.

[0017] In a preferred embodiment, R represents phenyl, and R1 is the same as R2.

[0018] In a preferred embodiment, the specific structure of the compound is any one of the following structures:

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028] An organic electroluminescent device includes an anode, a hole transport region, a light-emitting region, an electron transport region, and a cathode, and the hole transport region contains the compound containing a triarylamine and a phenanthrene structure.

[0029] In a preferred embodiment, the hole transport region sequentially includes a hole injection layer, a hole transport layer, and an electron blocking layer; both the hole injection layer and the hole transport layer contain the compound containing a triarylamine and a phenanthrene structure; preferably, the hole injection layer is a mixed film layer of the compound containing a triarylamine and a phenanthrene structure and a P-type doping material.

[0030] In a preferred embodiment, the light-emitting region contains a host material and a guest material, wherein the host material contains an anthracene group and the guest material is a fluorescent material;

[0031] In a preferred embodiment, the electron transport region contains a nitrogen-containing heterocyclic compound represented by the following general formula (3):

[0032]

[0033] In general formula (3), Ar1, Ar2, and Ar3 each independently represent a substituted or unsubstituted C6-C 30 aryl group, a substituted or unsubstituted C5-C containing one or more heteroatoms 30One of the heterocyclic groups;

[0034] L1 is selected from a single bond, a substituted or unsubstituted C6-C 30 arylene group, a substituted or unsubstituted C5-C containing one or more heteroatoms 30 One of the heteroarylene groups;

[0035] Each of the heteroatoms is independently selected from N, O or S; n represents 1 or 2;

[0036] X1, X2, X3 independently of each other represent N or CH, and at least one of X1, X2, X3 represents N.

[0037] In a preferred embodiment, the electron transport region includes an electron transport layer and an electron injection layer, wherein the electron transport layer contains the azacyclic compound; the electron injection layer is an N-type metal material.

[0038] In a preferred embodiment, the structure of the azacyclic compound is any one of the following compounds:

[0039]

[0040] In a preferred embodiment, the electron transport region includes an electron transport layer and an electron injection layer, wherein the electron transport layer contains the azacyclic compound; the electron injection layer is an N-type metal material.

[0041] The beneficial technical effects of the present invention are as follows:

[0042] The triarylamine and phenanthrene compounds of the present invention have a relatively high glass transition temperature, excellent film phase stability and excellent high-temperature weather resistance, so that the device will not age or crystallize due to the heat generated during the lighting process.

[0043] Since the compounds of the present invention have a small reorganization energy (the energy generated by the change in molecular configuration and environmental polarization caused by the change in electronic state), the compounds of the present application have a high mobility, thus having excellent hole transport performance, and being applied to OLED devices can significantly reduce the voltage of the device.

[0044] The compounds provided by the present invention have appropriate HOMO energy levels, can form stable CT complexes with P-doped materials at low doping ratios, further improve the hole injection efficiency, and reduce the risk of Cross-talk (due to the different turn-on voltages of red, green, and blue three pixels, causing color bleeding of red, green, and blue pixels, where the turn-on voltage of the blue pixel is the highest, and there is a risk of turning on adjacent pixel points when lighting the blue pixel).

[0045] In addition, by combining the triarylamine and phenanthrene compounds of the present invention with an azacyclic electron transport material, electrons and holes are in an optimal balance state, having not only relatively high efficiency but also excellent lifespan, especially the high-temperature lifespan of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic cross-sectional view of the organic electroluminescent device of the present invention.

[0047] In the figure: 1 is the substrate layer, 2 is the anode layer, 3 is the hole injection layer, 4 is the hole transport layer, 5 is the electron blocking layer, 6 is the light-emitting layer, 7 is the hole blocking layer, 8 is the electron transport layer, 9 is the electron injection layer, 10 is the cathode layer, and 11 is the CPL layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0049] It should be noted that the terms used here are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used here, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0050] In the present invention, unless otherwise stated, all operations are carried out under room temperature and normal pressure conditions.

[0051] In the present invention, unless otherwise specified, HOMO means the highest occupied molecular orbital, and LUMO means the lowest unoccupied molecular orbital. In addition, the "difference in HOMO energy levels" and "difference in LUMO energy levels" referred to in this specification mean the difference in the absolute value of each energy value. In addition, in the present invention, the HOMO and LUMO energy levels are represented by absolute values, and the comparison between energy levels is also a comparison of the magnitudes of their absolute values. Those skilled in the art know that the greater the absolute value of the energy level, the lower the energy of that energy level.

[0052] In the present invention, when a layer or an element is referred to as being "on" another layer or substrate, the layer or element can be directly on the other layer or substrate, or there can also be an intermediate layer. In addition, it will also be understood that when a layer is referred to as being "between" two layers, the layer can be the only layer between the two layers, or there can also be one or more intermediate layers. The same reference numerals throughout the text denote the same elements.

[0053] In the present invention, when describing electrodes, organic electroluminescent devices, and other structures, terms indicating orientation such as "above", "below", "top", and "bottom" only represent the orientation in a certain specific state and do not mean that the related structures can only exist in the stated orientation; on the contrary, if the structure can be repositioned, for example, inverted, the orientation of the structure is changed accordingly. Specifically, in the present invention, the "bottom" and "lower" sides of the electrode refer to the side of the electrode close to the substrate during the preparation process, and the opposite side away from the substrate is the "top" and "upper" sides.

[0054] In this specification, the term "substituted" means that one or more hydrogen atoms on a specified atom or group are replaced by a specified group, provided that it does not exceed the normal valence of the specified atom under the existing circumstances.

[0055] In this specification, the term "C6-C 30 aryl" refers to a completely unsaturated monocyclic, polycyclic, or fused polycyclic (i.e., rings sharing a pair of adjacent carbon atoms) system having 6 to 30 ring carbon atoms.

[0056] In this specification, the term "5- to 30-membered heteroaryl" refers to a saturated, partially saturated, or completely unsaturated cyclic group having 5 to 30 ring carbon atoms and containing at least one heteroatom selected from N, O, and S, including but not limited to heteroaryl, heterocycloalkyl, fused rings, or combinations thereof. When the heterocyclic group is a fused ring, each ring or all rings of the heterocyclic group can contain at least one heteroatom.

[0057] In this specification, substituted or unsubstituted fluorenyl refers to substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted diphenylfluorenyl, substituted or unsubstituted spirofluorenyl.

[0058] More precisely, substituted or unsubstituted C6-C 30 aryl and / or substituted or unsubstituted 5- to 30-membered heteroaryl refers to substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted condensed tetraphenyl, substituted or unsubstituted pyrenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted p-terphenyl, substituted or unsubstituted m-terphenyl, substituted or unsubstituted A base, a substituted or unsubstituted terphenyl, a substituted or unsubstituted perylene group, a substituted or unsubstituted indene group, a substituted or unsubstituted furyl group, a substituted or unsubstituted thienyl group, a substituted or unsubstituted pyrrolyl group, a substituted or unsubstituted pyrazolyl group, a substituted or unsubstituted imidazolyl group, a substituted or unsubstituted triazolyl group, a substituted or unsubstituted oxazolyl group, a substituted or unsubstituted thiazolyl group, a substituted or unsubstituted oxadiazolyl group, a substituted or unsubstituted thiadiazolyl group, a substituted or unsubstituted pyridyl group, a substituted or unsubstituted pyrimidinyl group, a substituted or unsubstituted pyrazinyl group, a substituted or unsubstituted triazinyl group, a substituted or unsubstituted benzofuryl group, a substituted or unsubstituted benzothienyl group, a substituted or unsubstituted benzimidazolyl group, a substituted or unsubstituted indolyl group, a substituted or unsubstituted quinolinyl group, a substituted or unsubstituted isoquinolinyl group, a substituted or unsubstituted quinazolinyl group, a substituted or unsubstituted quinoxalinyl group, a substituted or unsubstituted naphthyridinyl group, a substituted or unsubstituted benzoxazinyl group, a substituted or unsubstituted benzothiazinyl group, a substituted or unsubstituted acridinyl group, a substituted or unsubstituted phenazinyl group, a substituted or unsubstituted phenothiazinyl group, a substituted or unsubstituted phenoxazinyl group, a substituted or unsubstituted fluorene group, a substituted or unsubstituted dibenzofuryl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted carbazolyl group, a combination thereof, or a fused ring of a combination of the foregoing groups, but not limited thereto.

[0059] In this specification, a substituted or unsubstituted C6-C 30 arylene or a substituted or unsubstituted C5-C 30 heteroarylene respectively refers to a substituted or unsubstituted C6-C 30 arylene or a substituted or unsubstituted C5-C 30 heteroarylene as defined above and having two linking groups, such as a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthylene group, a substituted or unsubstituted anthrylene group, a substituted or unsubstituted phenanthrylene group, a substituted or unsubstituted tetracenylene group, a substituted or unsubstituted pyrenylene group, a substituted or unsubstituted biphenylene group, a substituted or unsubstituted p-terphenylenylene group, a substituted or unsubstituted m-terphenylenylene group, a substituted or unsubstituted a group selected from the group consisting of a group, a substituted or unsubstituted meta-linked terphenyl group, a substituted or unsubstituted perylene group, a substituted or unsubstituted indene group, a substituted or unsubstituted furan group, a substituted or unsubstituted thiophene group, a substituted or unsubstituted pyrrole group, a substituted or unsubstituted pyrazole group, a substituted or unsubstituted imidazole group, a substituted or unsubstituted triazole group, a substituted or unsubstituted oxazole group, a substituted or unsubstituted thiazole group, a substituted or unsubstituted oxadiazole group, a substituted or unsubstituted thiadiazole group, a substituted or unsubstituted pyridine group, a substituted or unsubstituted pyrimidine group, a substituted or unsubstituted pyrazine group, a substituted or unsubstituted triazine group, a substituted or unsubstituted benzofuran group, a substituted or unsubstituted benzothiophene group, a substituted or unsubstituted benzimidazole group, a substituted or unsubstituted indole group, a substituted or unsubstituted quinoline group, a substituted or unsubstituted isoquinoline group, a substituted or unsubstituted quinazoline group, a substituted or unsubstituted quinoxaline group, a substituted or unsubstituted naphthyridine group, a substituted or unsubstituted benzoxazine group, a substituted or unsubstituted benzothiazine group, a substituted or unsubstituted acridine group, a substituted or unsubstituted phenazine group, a substituted or unsubstituted phenothiazine group, a substituted or unsubstituted phenoxazine group, a substituted or unsubstituted fluorene group, a substituted or unsubstituted dibenzofuran group, a substituted or unsubstituted dibenzothiophene group, a substituted or unsubstituted carbazole group, a combination thereof, or a fused ring of a combination of the foregoing groups, but not limited thereto.

[0060] In the present specification, the hole characteristic refers to the characteristic of being able to supply electrons when an electric field is applied and being attributable to the conductive characteristic according to the highest occupied molecular orbital (HOMO) level, and the characteristic that the holes formed in the anode are easily injected into the light-emitting layer and transported in the light-emitting layer.

[0061] In the present specification, the electron characteristic refers to the characteristic of being able to accept electrons when an electric field is applied and being attributable to the conductive characteristic according to the lowest unoccupied molecular orbital (LUMO) level, and the characteristic that the electrons formed in the cathode are easily injected into the light-emitting layer and transported in the light-emitting layer.

[0062] organic electroluminescent device

[0063] The present invention provides an organic electroluminescent device using a compound containing a triarylamine and a phenanthrene structure represented by the general formula (1).

[0064] In an exemplary embodiment of the present invention, the organic electroluminescent device may include an anode, a hole transport region, a light-emitting region, an electron transport region, and a cathode.

[0065] The organic electroluminescent device of the present invention may be a bottom-emitting organic electroluminescent device, a top-emitting organic electroluminescent device, or a stacked organic electroluminescent device, and no specific limitation is imposed thereon.

[0066] In the organic electroluminescent device of the present invention, any substrate commonly used in organic electroluminescent devices can also be used. Examples thereof are transparent substrates such as glass or transparent plastic substrates; opaque substrates such as silicon substrates; and flexible polyimide (PI) film substrates. Different substrates have different mechanical strengths, thermal stabilities, transparencies, surface smoothnesses, and water resistances. Depending on the nature of the substrate, their usage directions are different. In the present invention, a transparent substrate is preferably used. The thickness of the substrate is not particularly limited.

[0067] Anode

[0068] Preferably, an anode can be formed on the substrate. In the present invention, the anode and the cathode face each other. The anode can be made of a conductor having a relatively high work function to assist hole injection, and can be, for example, a metal such as nickel, platinum, copper, zinc, silver, or an alloy thereof; a metal oxide such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); a combination of a metal and a metal oxide such as ZnO and Al or ITO and Ag; a conductive polymer such as poly(3-methylthiophene), poly(3,4-(ethylene-1,2-dioxythiophene)), and polyaniline, but not limited thereto. The thickness of the anode depends on the material used, and is generally 50 - 500 nm, preferably 70 - 300 nm, and more preferably 100 - 200 nm. In the present invention, a combination of a metal and a metal oxide, ITO and Ag, is preferably used.

[0069] Cathode

[0070] The cathode can be made of a conductor having a relatively low work function to assist electron injection, and can be, for example, a metal or an alloy thereof such as magnesium, calcium, sodium, potassium, titanium, indium, aluminum, silver, tin, and combinations thereof; multilayer structure materials such as LiF / Al, Li2O / Al, and BaF2 / Ca, but not limited thereto. The thickness of the cathode depends on the material used, and is generally 10 - 50 nm, preferably 15 - 20 nm.

[0071] Light-emitting region

[0072] In the present invention, the light-emitting region can be disposed between the anode and the cathode, and can include at least one host material and at least one guest material. As the host material and the guest material of the light-emitting region of the organic electroluminescent device of the present invention, light-emitting layer materials known in the prior art for organic electroluminescent devices can be used. The host material can be, for example, a thiazole derivative, a benzimidazole derivative, a polydialkylfluorene derivative, or 4,4'-bis(9-carbazolyl)biphenyl (CBP). The host material can use a compound containing an anthracene group. The guest material can be, for example, quinacridone, coumarin, rubrene, perylene and its derivatives, benzopyran derivatives, rhodamine derivatives, or aminostyrene derivatives.

[0073] In a preferred embodiment of the present invention, the light-emitting region contains one or two host material compounds.

[0074] In a preferred embodiment of the present invention, the light-emitting region contains two host material compounds, and the two host material compounds form an exciplex.

[0075] In a preferred embodiment of the present invention, the host material of the light-emitting region used is selected from one or more of the following compounds BH-1 to BH-11:

[0076]

[0077] In the present invention, the light-emitting region may contain a phosphorescent or fluorescent guest material to improve the fluorescence or phosphorescent properties of the organic electroluminescent device. Specific examples of the phosphorescent guest material include metal complexes such as iridium and platinum. For the fluorescent guest material, those commonly used in the art can be used. In a preferred embodiment of the present invention, the guest material of the light-emitting film layer used is selected from one of the following compounds BD-1 to BD-10:

[0078]

[0079]

[0080] In the light-emitting region of the present invention, the ratio of the host material to the guest material used is 99:1 - 70:30, preferably 99:1 - 85:15, and more preferably 97:3 - 87:13, based on mass.

[0081] The thickness of the light-emitting region can be 10 - 50 nm, preferably 15 - 30 nm, but the thickness is not limited to this range.

[0082] Hole transport region

[0083] In the organic electroluminescent device of the present invention, the hole transport region is disposed between the anode and the light-emitting region, and it includes a hole injection layer, a hole transport layer, and an electron blocking layer.

[0084] Hole injection layer

[0085] The hole injection material used in the hole injection layer (also known as the anode interface buffer layer) is a material that can fully accept holes from the anode at a low voltage, and the highest occupied molecular orbital (HOMO) of the hole injection material is preferably a value between the work function of the anode material and the HOMO of the adjacent organic material layer. In a preferred embodiment of the present invention, the hole injection layer is a mixed film layer of a host organic material and a P-type doping material. In order to enable holes to be smoothly injected from the anode into the organic film layer, the HOMO energy level of the host organic material and the P-type doping material must have certain characteristics to expect the occurrence of a charge transfer state between the host material and the doping material, achieve ohmic contact between the hole injection layer and the anode, and thus achieve efficient injection of holes from the electrode into the hole injection layer. This characteristic is summarized as: the difference between the HOMO energy level of the host material and the LUMO energy level of the P-type doping material ≤ 0.4 eV. Therefore, for hole-type host materials with different HOMO energy levels, different P-type doping materials need to be selected to match them in order to achieve ohmic contact at the interface and improve the hole injection effect.

[0086] Preferably, specific examples of the host organic material include: metal porphyrins, oligothiophenes, organic materials of arylamines, hexanitrile hexaazatriphenylene, quinacridone-based organic materials, perylene-based organic materials, anthraquinone, and conductive polymers such as polyanilines and polythiophenes; but not limited thereto. Preferably, the host organic material is an organic material of arylamines.

[0087] Preferably, the P-type doping material is a compound with charge conductivity selected from the following: quinone derivatives or metal oxides, such as tungsten oxide and molybdenum oxide, but not limited thereto.

[0088] In a preferred embodiment of the present invention, the P-type doping material used is any one of the following compounds HI1 to HI8:

[0089]

[0090] In an embodiment of the present invention, the ratio of the host organic material to the P-type doping material used is 99:1 - 95:5, preferably 99:1 - 97:3, based on mass.

[0091] In a preferred embodiment of the present invention, the hole injection layer is a mixed film layer of an arylamine compound and a P-type doping material, and the arylamine compound is an arylamine compound of general formula (1).

[0092] The thickness of the hole injection layer of the present invention can be 5 - 20 nm, preferably 8 - 15 nm, but the thickness is not limited to this range.

[0093] Hole transport layer

[0094] In the organic electroluminescent device of the present invention, a hole transport layer may be disposed above the hole injection layer. The hole transport material is a suitable material with a high hole mobility, which can accept holes from the anode or the hole injection layer and transfer the holes into the light-emitting layer. Specific examples thereof include, but are not limited to, arylamine organic materials, conductive polymers, block copolymers having both a conjugated portion and a non-conjugated portion, etc. In a preferred embodiment, the hole transport layer contains the same arylamine compound as the hole injection layer.

[0095] The thickness of the hole transport layer of the present invention may be 80 - 200 nm, preferably 100 - 150 nm, but the thickness is not limited to this range.

[0096] Electron blocking layer

[0097] In the organic electroluminescent device of the present invention, an electron blocking layer may be disposed between the hole transport layer and the light-emitting layer, and in particular, in contact with the light-emitting layer. The electron blocking layer is provided in contact with the light-emitting layer, and thus, the hole transfer at the interface between the light-emitting layer and the hole transport layer can be precisely controlled. In one embodiment of the present invention, the electron blocking layer material is selected from carbazole-based arylamine derivatives. The thickness of the electron blocking layer may be 5 - 20 nm, preferably 8 - 15 nm, but the thickness is not limited to this range.

[0098] The present invention does not deny the substrate matching principle of traditional hole materials, but is a further superposition on the physical property parameters of traditional material screening, that is, it recognizes the influence effects of HOMO energy level, carrier mobility, film phase state stability, heat resistance stability of materials, etc. on the hole injection efficiency of organic electroluminescent devices. On this basis, the material screening conditions are further increased, and then by selecting more excellent organic electroluminescent materials for device matching, the material selection accuracy for preparing high-performance organic electroluminescent devices is improved.

[0099] Electron transport region

[0100] In the organic electroluminescent device of the present invention, the electron transport region is disposed between the light-emitting region and the cathode, and includes an electron transport layer and an electron injection layer, but is not limited thereto.

[0101] Electron injection layer

[0102] The electron injection layer can be disposed between the electron transport layer and the cathode. The material of the electron injection layer is generally preferably a material with a low work function, so that electrons can be easily injected into the organic functional material layer. Preferably, the material of the electron injection layer is an N-type metal material. As the material of the electron injection layer of the organic electroluminescent device of the present invention, the materials known in the prior art for the electron injection layer of the organic electroluminescent device can be used, for example, lithium; lithium salts such as lithium 8-hydroxyquinoline, lithium fluoride, lithium carbonate or lithium azide; or cesium salts, cesium fluoride, cesium carbonate or cesium azide. The thickness of the electron injection layer of the present invention can be 0.1-5 nm, preferably 0.5-3 nm and more preferably 0.8-1.5 nm, but the thickness is not limited to this range.

[0103] Electron transport layer

[0104] The electron transport layer can be disposed above the light-emitting film layer or (if present) the hole blocking layer. The material of the electron transport layer is a material that can easily receive electrons from the cathode and transfer the received electrons to the light-emitting layer. A material with a high electron mobility is preferred. As the electron transport layer of the organic electroluminescent device of the present invention, the materials known in the prior art for the electron transport layer of the organic electroluminescent device can be used, for example, metal complexes of hydroxyquinoline derivatives represented by Alq3, BAlq and LiQ, various rare earth metal complexes, triazole derivatives, triazine derivatives such as 2,4-bis(9,9-dimethyl-9H-fluoren-2-yl)-6-(naphthalen-2-yl)-1,3,5-triazine (CAS No.: 1459162-51-6), imidazole derivatives such as 2-(4-(9,10-di(naphthalen-2-yl)anthracen-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole (CAS No.: 561064-11-7, commonly known as LG201), oxadiazole derivatives, etc.

[0105] In the preferred organic electroluminescent device of the present invention, the electron transport region contains a nitrogen-containing heterocyclic compound represented by the following general formula (3):

[0106]

[0107] In general formula (3), Ar1, Ar2, and Ar3 each independently represent a substituted or unsubstituted C6-C 30 aryl, a substituted or unsubstituted C5-C containing one or more heteroatoms 30 heteroaryl;

[0108] L1 is selected from a single bond, a substituted or unsubstituted C6-C 30 arylene, a substituted or unsubstituted C5-C containing one or more heteroatoms 30 heteroarylene;

[0109] The heteroatom is N, O or S; n represents 1 or 2;

[0110] X1, X2, X3 each independently represent N or CH, and at least one of X1, X2, X3 represents N.

[0111] Preferably, the azacyclic compound of the general formula (3) is represented by the general formula (3-1):

[0112]

[0113] wherein Ar1, Ar2, Ar3, X1, X2, X3, L1 are each as defined above.

[0114] In a preferred embodiment of the present invention, the electron transport layer comprises any one of the compounds selected from the following:

[0115]

[0116]

[0117] In a more preferred embodiment of the present invention, the electron transport layer comprises any one of the compounds selected from the following:

[0118]

[0119] The thickness of the electron transport layer of the present invention can be 10 - 80 nm, preferably 20 - 60 nm and more preferably 25 - 45 nm, but the thickness is not limited to this range.

[0120] Covering layer

[0121] In order to improve the light extraction efficiency of the organic electroluminescent device, a light extraction layer (i.e., CPL layer, also referred to as a covering layer) can also be added on the cathode of the device. According to the principles of optical absorption and refraction, the refractive index of the CPL covering layer material should be as high as possible, and the absorption coefficient should be as small as possible. Any material known in the art can be used as the CPL layer material, such as Alq3, or N4,N4'-diphenyl-N4,N4'-bis(9-phenyl-3-carbazolyl)biphenyl-4,4'-diamine. The thickness of the CPL covering layer is generally 5 - 300 nm, preferably 20 - 100 nm and more preferably 40 - 80 nm.

[0122] The organic electroluminescent device of the present invention may further include a packaging structure. The packaging structure can be a protective structure for preventing external substances such as moisture and oxygen from entering the organic layer of the organic electroluminescent device. The packaging structure can be, for example, a can, such as a glass can or a metal can; or a thin film covering the entire surface of the organic layer.

[0123] Hereinafter, an organic electroluminescent device according to an embodiment of the present invention will be described.

[0124] In the drawings, for clarity, the thicknesses of layers, films, substrates, regions, etc. are enlarged. Throughout the specification, like reference numerals denote like elements. It should be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, no intervening elements are present.

[0125] The present invention also relates to a method for manufacturing an organic electroluminescent device, which includes successively laminating an anode, a hole injection layer, a hole transport layer, an electron blocking layer, an organic film layer, an electron transport layer, an electron injection layer, and a cathode on a substrate, and optionally a cover layer. In this regard, methods such as vacuum deposition, vacuum evaporation, spin coating, casting, the LB method, inkjet printing, laser printing, or LITI can be used, but are not limited thereto. In the present invention, the vacuum evaporation method is preferably used to form the respective layers. Those skilled in the art can conventionally select the respective process conditions in the vacuum evaporation method according to actual needs.

[0126] In addition, it should be noted that the materials for forming the respective layers in the present invention can each form a film and be used as a single layer, can also be mixed with other materials and then form a film and be used as a single layer, and can also be a stacked structure between layers formed separately into films, a stacked structure between layers formed by mixing, or a stacked structure of a layer formed separately into a film and a layer formed by mixing.

[0127] The present invention also relates to a full-color display device having red, green, and blue three pixels, particularly a flat panel display device, including the organic electroluminescent device of the present invention. The display device may further include at least one thin film transistor. The thin film transistor may include a gate electrode, a source electrode, a drain electrode, a gate insulating layer, and an active layer, wherein one of the source electrode and the drain electrode can be electrically connected to the anode of the organic electroluminescent device. The active layer may include crystalline silicon, amorphous silicon, an organic semiconductor, or an oxide semiconductor, but is not limited thereto.

[0128] Exemplary embodiments have been disclosed herein. Although specific terms are used therein, these terms are used only and are to be construed only as general and descriptive meanings and not for purposes of limitation. In some cases, as will be apparent to those of ordinary skill in the art upon the filing of the present application, unless specifically stated, features, characteristics, and / or elements described in connection with a particular embodiment can be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments. Accordingly, those skilled in the art will understand that various changes can be made in form and detail without departing from the spirit and scope of the present invention.

[0129] The following examples are intended to better explain the present invention, but the scope of the present invention is not limited thereto.

[0130] Example

[0131] Unless otherwise specified, various materials used in the following examples and comparative examples are commercially available or can be obtained by methods known to those skilled in the art.

[0132] Example 1: Synthesis of Compound 7

[0133]

[0134] In a 250 ml three-necked flask, under a nitrogen atmosphere, 0.012 mol of raw material A1, 0.01 mol of raw material B1, 0.03 mol of potassium tert-butoxide, 1×10 -4 mol of tris(dibenzylideneacetone)dipalladium Pd2(dba)3, 1×10 -4 mol of triphenylphosphine, and 150 ml of toluene were added, and the mixture was heated to reflux for 12 hours. Sampling and thin-layer chromatography showed that the reaction was complete. It was naturally cooled, filtered, the filtrate was rotary evaporated, and passed through a silica gel column (silica gel 100-200 mesh, eluent: chloroform:n-hexane = 1:2 (volume ratio)) to obtain Compound 7. Elemental analysis structure (molecular formula C 50 H 35 N): The analytical measured values were: C, 92.40; H, 5.49; N, 2.17. LC-MS([M+H] + ) : The measured value was 650.33.

[0135] Example 2: Synthesis of Compound 18

[0136]

[0137] In a 250 ml three-necked flask, under a nitrogen atmosphere, 0.01 mol of raw material C1, 0.01 mol of raw material D1, 0.03 mol of potassium tert-butoxide, 1×10 -4 mol of tris(dibenzylideneacetone)dipalladium Pd2(dba)3, 1×10 -4 mol of triphenylphosphine, and 150 ml of toluene were added, and the mixture was heated to reflux for 12 hours. Sampling and thin-layer chromatography showed that the reaction was complete. It was naturally cooled, filtered, the filtrate was rotary evaporated, and passed through a silica gel column (silica gel 100-200 mesh, eluent: chloroform:n-hexane = 1:2 (volume ratio)) to obtain Intermediate 1. Elemental analysis structure (molecular formula C 24 H 19 N); LC-MS([M+H] + ) : The measured value was 322.21.

[0138] A 250 ml three-necked flask was charged with 0.012 mol of raw material A1, 0.01 mol of intermediate 1, 0.03 mol of potassium tert-butoxide, 1×10 -4 mol of tris(dibenzylideneacetone)dipalladium Pd2(dba)3, 1×10 -4 mol of triphenylphosphine, 150 ml of toluene, and the mixture was heated under reflux for 12 hours. Samples were taken for thin-layer chromatography, indicating that the reaction was complete. The reaction mixture was allowed to cool naturally, filtered, and the filtrate was concentrated by rotary evaporation. The residue was purified by passing through a silica gel column (silica gel 100 - 200 mesh, eluent: chloroform:n-hexane = 1:2 (volume ratio)) to obtain compound 18. Elemental analysis results (molecular formula C 44 H 31 N): The measured values were: C, 92.10; H, 5.47; N, 2.41. LC-MS ([M+H] + ): The measured value was 574.27.

[0139] The following compounds were prepared in the same manner as in Example 1 or 2, and the synthesis raw materials are shown in Table 1 below. The synthesis of the materials of the present invention refers to Patent CN110577511A.

[0140] In order to analyze the structures of the compounds prepared in the examples, the molecular weights were measured by LC-MS as shown in Table 1:

[0141] Table 1

[0142]

[0143]

[0144] Detection method

[0145] Glass transition temperature Tg: Measured by differential scanning calorimetry (DSC, Netzsch DSC204F1 differential scanning calorimeter), heating rate 10 °C / min.

[0146] HOMO energy level: Measured by an ionization energy test system (IPS-3) under vacuum environment.

[0147] Eg energy level: Calculated based on the intersection of the tangent line drawn from the rising side of the first absorption peak and the baseline of the UV absorption spectrum of the single-layer film of the material.

[0148] Hole mobility: Measured by the space charge limited current method (SCLC) using a single-charge device made of the material.

[0149] Triplet energy level T1: Measured by a Horiba Fluorolog-3 series fluorescence spectrometer with the material dissolved in toluene solution.

[0150] See Table 2 for the specific physical property test results.

[0151] Table 2

[0152]

[0153] As can be seen from the data in Table 2 above, the compounds of the present invention have appropriate HOMO energy levels, high hole mobilities, and wide band gaps (Eg), and can achieve organic electroluminescent devices with high efficiency, low voltage, and long lifespan.

[0154] Preparation of organic electroluminescent devices

[0155] The molecular structural formulas of the materials involved in the following preparation process are shown as follows:

[0156]

[0157] Device Comparative Example 1

[0158] Prepare an organic electroluminescent device according to the following steps:

[0159] a) Use transparent glass as the substrate, Substrate Layer 1, wash the anode layer 2 (Ag (100 nm)) thereon, that is, perform alkali washing, pure water washing, drying in sequence, and then perform ultraviolet-ozone washing to remove organic residues on the surface of the anode layer;

[0160] b) On the washed anode layer 2, use a vacuum evaporation device to evaporate HT1 and HI1 with a film thickness of 10 nm as the hole injection layer 3, and the mass ratio of HT1 and HI1 is 97:3;

[0161] c) On the hole injection layer 3, evaporate the hole transport layer 4 by vacuum evaporation, and the hole transport layer material is compound HT1 with a thickness of 117 nm;

[0162] d) On the hole transport layer 4, evaporate the electron blocking layer 5 by vacuum evaporation, and the electron blocking layer material is compound EB-1 with a thickness of 10 nm;

[0163] e) On the electron blocking layer 5, evaporate the light-emitting layer 6 by vacuum evaporation. The light-emitting layer 6 uses BH-1 as the host material and BD-1 as the guest material, and the mass ratio of the host material to the guest material is 97:3, with a thickness of 20 nm;

[0164] f) On the light-emitting layer 6, continue to evaporate HB1 as the hole blocking layer 7 with a film thickness of 8 nm;

[0165] g) On the hole blocking layer 7, evaporate ET1 and LiQ by vacuum evaporation, and the mass ratio of ET1 and LiQ is 1:1 with a thickness of 30 nm, and this layer serves as the electron transport layer 8;

[0166] h) On the electron transport layer 8, LiF is deposited by vacuum evaporation to a thickness of 1 nm, and this layer is the electron injection layer 9;

[0167] i) On the electron injection layer 9, a Mg:Ag (mass ratio 1:9) electrode layer is deposited by vacuum evaporation to a thickness of 16 nm, and this layer is the cathode layer 10;

[0168] j) On the cathode layer 10, a CPL material CPL-1 is deposited by vacuum evaporation to a thickness of 70 nm, and this layer is the CPL layer 11.

[0169] Device comparative example 2-3 is carried out according to the method of device comparative example 1, except that the organic materials in steps b) / c) are respectively replaced with the organic materials shown in Table 3. Device comparative examples 4-6 are carried out according to the method of device comparative example 1, except that the organic materials in b) / c) / g) are respectively replaced with the organic materials shown in Table 3. Device preparation examples 1-17 are carried out according to the method of device comparative example 1, except that the organic materials in steps b) / c) are respectively replaced with the organic materials shown in Table 3. Device preparation examples 18-34 are carried out according to the method of device comparative example 1, except that the organic materials in b) / c) / g) are respectively replaced with the organic materials shown in Table 3.

[0170] Table 3

[0171]

[0172]

[0173] Taking the row of Example 1 in the above table as an example, “7:HI1(3% 10nm)” in the second column table means that the materials used for the hole injection layer are compound (7) and the P-type doping material HI1, 3% refers to the weight ratio of the P-type doping material HI1 in the materials used for the hole injection layer: 10 nm represents the thickness of this layer; “7(117nm)” in the third column table means that the material used is compound (7) and the thickness of this layer is 117 nm. The meanings in other tables can be deduced by analogy.

[0174] After preparing the OLED light-emitting device as described above, the cathode and anode are connected by a known driving circuit, and various performances of the device are measured.

[0175] The measured performance results of the devices of Examples 1-34 and Comparative Examples 1-6 are shown in Table 4.

[0176] Table 4

[0177]

[0178] Note: The voltage, current efficiency and color coordinates were measured using an IVL (current-voltage-luminance) test system (Suzhou FushiDa Scientific Instrument Co., Ltd.), and the current density during the test was 10 mA / cm 2 ; The lifetime test system is the EAS-62C OLED device lifetime tester of System Technology Research Co., Ltd. of Japan; LT95 refers to the time taken for the device brightness to decay to 95% at a specific brightness; the test temperature for high-temperature lifetime is 85 °C, and LT80 refers to the time taken for the device brightness to decay to 80% at a specific brightness.

[0179] From the results of Comparative Examples 1-3 and Device Examples 1-17 in Table 4, it can be seen that by using the triarylamine and phenanthrene compounds of the present invention as the hole injection and hole transport layer materials, due to their high carrier transport rate, the device voltage is effectively reduced and the device lifetime is improved.

[0180] From the results of Comparative Examples 4-6 and Device Examples 18-34 in Table 4, it can be seen that the combination of the triarylamine and phenanthrene compounds of the present invention with specific electron transport layer materials effectively improves the efficiency and lifetime of the device.

[0181] The compound of the present invention contains a phenanthrene group, which can effectively increase the glass transition temperature of the material. Also, because this group has high heat resistance stability, the compound of the present invention application has excellent film phase stability and evaporation stability, effectively improving the interface stability of the device under high-temperature conditions, and the device has excellent high-temperature lifetime.

[0182] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A compound containing a triarylamine and a phenanthrene structure, characterized in that, The structure of the said compound is shown in general formula (1): In general formula (1), L, L1, and L2 each independently represent a single bond, a phenylene group, a naphthylene group, a biphenylene group, a furyl group, a benzofuryl group, or a dibenzofuryl group; R1 and R2 each independently represent one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted benzofuryl group, a substituted or unsubstituted dibenzofuryl group, a substituted or unsubstituted dimethylfluorene group, a substituted or unsubstituted diphenylfluorene group, a substituted or unsubstituted spirofluorene group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted benzodioxin, a substituted or unsubstituted acenaphthylene group, a substituted or unsubstituted piperonyl group, a substituted or unsubstituted indenyl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted benzothiophene group, or a substituted or unsubstituted dibenzothiophene group; R represents a phenyl group, a naphthyl group, a biphenyl group, a furyl group, a benzofuryl group, or a dibenzofuryl group; The substituents for the substituting groups are each independently selected from one or more of deuterium, tert-butyl group, phenyl group, naphthyl group, biphenyl group, carbazolyl group, benzofuryl group, dibenzofuryl group, fluorene group, phenanthryl group, acenaphthylene group, and piperonyl group.

2. The compound containing a triarylamine and a phenanthrene structure according to claim 1, characterized in that, The said R1 and R2 each independently represent one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted benzofuryl group, a substituted or unsubstituted dibenzofuryl group, a substituted or unsubstituted dimethylfluorene group, a substituted or unsubstituted diphenylfluorene group, a substituted or unsubstituted spirofluorene group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted benzodioxin, a substituted or unsubstituted acenaphthylene group, a substituted or unsubstituted piperonyl group, a substituted or unsubstituted indenyl group, or a substituted or unsubstituted carbazolyl group; The substituents for the substituting groups are one or more of deuterium, tert-butyl group, phenyl group, naphthyl group, biphenyl group, carbazolyl group, benzofuryl group, dibenzofuryl group, fluorene group, phenanthryl group, acenaphthylene group, and piperonyl group.

3. The compound containing a triarylamine and a phenanthrene structure according to claim 1, wherein R represents a phenyl group, and R2 represents a biphenyl group or a phenyl group.

4. The compound containing a triarylamine and a phenanthrene structure according to claim 1, characterized in that, R represents a phenyl group, and R1 is the same as R2.

5. The compound containing a triarylamine and a phenanthrene structure according to claim 1, characterized in that, The specific structure of the said compound is any one of the following structures:

6. An organic electroluminescent device, comprising an anode, a hole transport region, a light-emitting region, an electron transport region and a cathode, characterized in that, The hole transport region contains the compound containing a triarylamine and a phenanthrene structure as described in any one of claims 1-5.

7. The organic electroluminescent device according to claim 6, wherein, The hole transport region sequentially includes a hole injection layer, a hole transport layer, and an electron blocking layer; both the hole injection layer and the hole transport layer contain the compound containing a triarylamine and a phenanthrene structure as described in any one of claims 1-5.

8. The organic electroluminescent device according to claim 7, wherein The hole injection layer is a mixed film layer of the compound containing a triarylamine and a phenanthrene structure as described in any one of claims 1-5 and a P-type doping material.

9. The organic electroluminescent device according to claim 6, characterized in that, The light-emitting region contains a host material and a guest material, wherein the host material contains an anthracene group and the guest material is a fluorescent material.

10. The organic electroluminescent device according to claim 6, wherein, The electron transport region contains a nitrogen-containing heterocyclic compound represented by the following general formula (3): In general formula (3), Ar1, Ar2, and Ar3 each independently represent a C6-C 30 aryl group, a C5-C 30 heteroaryl group containing one or more heteroatoms; L1 is selected from a single bond, a C6-C 30 arylene, a C5-C containing one or more heteroatoms 30 heteroarylene; The heteroatoms are each independently selected from N, O, or S; n represents 1 or 2; X1, X2, and X3 each independently represent N or CH, and at least one of X1, X2, and X3 represents N.

11. The organic electroluminescent device according to claim 10, characterized in that, The electron transport region includes an electron transport layer and an electron injection layer, wherein the electron transport layer contains the azacyclic compound described in claim 10; the electron injection layer is an N-type metal material.

Images