A composition and its application in organic electroluminescent device

Abstract

A composition comprising a compound represented by formula (I) and a compound represented by formula (II): #imgabs0#R 1 ~R 6 Each independently represents H, halogen, cyano, nitro, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C6-C30 arylamino, or substituted or unsubstituted C3-C30 heteroarylamino, R 1 ~R 6 The number of each is independently an integer greater than 1; 3 Optionally fused with the connected benzene ring to form a naphthalene ring structure, L 1 , L 2 , L 3 Each is independently a single bond, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C3-C20 heteroarylene group; Ar 1 、Ar 2 、Ar 3 Each is independently a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C6-C20 heteroaryl group, a substituted or unsubstituted C6-C20 arylamino group, or a substituted or unsubstituted C3-C20 heteroarylamino group, at least one of which is an electron-deficient group.

Description

Technical Field

[0001] The present invention relates to the field of display, and in particular to an organic light emitting diode and a manufacturing method thereof, and a display panel of the organic light emitting diode. Background Art

[0002] In recent years, optoelectronic devices based on organic materials have become increasingly popular. The inherent flexibility of organic materials makes them very suitable for manufacturing on flexible substrates. Beautiful and cool optoelectronic products can be designed and produced according to demand, gaining unparalleled advantages over inorganic materials. Examples of such organic optoelectronic devices include organic light-emitting diodes (OLEDs), organic field-effect transistors, organic photovoltaic cells, organic sensors, etc. Among them, OLEDs have developed particularly rapidly and have achieved commercial success in the field of information display. OLEDs can provide highly saturated red, green, and blue colors. Full-color display devices made with them do not require additional backlight sources and have the advantages of dazzling colors, being light, thin, and soft.

[0003] The core of an OLED device is a thin film structure containing a variety of organic functional materials. Common functional organic materials include hole injection materials, hole transport materials, hole blocking materials, electron injection materials, electron transport materials, electron blocking materials, as well as luminescent host materials and luminescent guest materials (dyes). When power is applied, electrons and holes are injected and transported to the light-emitting region, where they recombine, generating excitons and emitting light.

[0004] As OLED products gradually enter the market, demand for their performance is growing. Current OLED materials and device structures cannot fully address issues such as efficiency, lifespan, and cost. Through careful consideration and continuous experimentation, the researchers of the present invention have discovered an ingenious molecular design, described in detail below. Surprisingly, the composition disclosed in this invention is highly suitable for OLED applications and improves device performance. Summary of the Invention

[0005] Problems to be solved by the invention

[0006] To achieve energy conservation and environmental protection, people are increasingly demanding higher performance from OLED products, initially focusing on improving luminous efficiency or reducing the threshold voltage, to now expecting both. In light of this, the present invention provides a composition for organic electroluminescent devices to meet the ever-increasing demand for improved optoelectronic performance in OLED devices.

[0007] An object of the present invention is to provide an organic electroluminescent composition that is applicable to organic electroluminescent devices, particularly OLEDs, and can improve the luminous efficiency of OLEDs while reducing the starting and ending voltages, and can also increase the life of devices using the composition.

[0008] Another object of the present invention is to provide an organic light emitting diode using the organic electroluminescent composition.

[0009] Another object of the present invention is to provide a display panel using the above-mentioned organic light emitting diode.

[0010] Another object of the present invention is to provide a method for manufacturing the organic light emitting diode and display panel.

[0011] Solutions to the Problem

[0012] After intensive research, the inventors discovered that using two types of compounds with specific structures as light-emitting layer compounds can solve the above-mentioned problems and obtain an OLED with improved luminous efficiency, lower starting and falling voltage, and extended life compared to the existing technology.

[0013] Specifically, one aspect of the present invention provides a composition, characterized in that:

[0014] Comprising a compound represented by formula (I) and a compound represented by formula (II):

[0015]

[0016] Among them, R 1 ~R 6 Each independently represents H, halogen, cyano, nitro, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C6-C30 arylamino, or substituted or unsubstituted C3-C30 heteroarylamino, R 1 ~R 6 The number of each is independently an integer greater than 1; 3 Optionally fused with the attached benzene ring to form a naphthalene ring structure,

[0017] L 1 、L 2 、L 3 Each is independently a single bond, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C3-C20 heteroarylene group;

[0018] Ar 1 、Ar 2 、Ar 3 Each is independently a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C6-C20 heteroaryl group, a substituted or unsubstituted C6-C20 arylamino group, or a substituted or unsubstituted C3-C20 heteroarylamino group, at least one of which is an electron-deficient group;

[0019] When the above-mentioned substituted or unsubstituted group has a substituent, the substituent is selected from one or a combination of two or more of halogen, cyano, nitro, amino, C1-C10 alkyl, C1-C10 alkoxy, C3-C10 cycloalkyl, C3-C10 heterocycloalkyl, C6-C20 aryl, and C3-C20 heteroaryl.

[0020] The specific reason why the above-mentioned composition of the present invention has excellent performance as a light-emitting layer material is still unclear. It is speculated that the following reasons may be the reason: the composition simultaneously contains the compound represented by formula (I) and the compound represented by formula (II), introduces indole and carbazole with a shallow HOMO energy level, and macro-controls the transmission of holes inside the light-emitting layer. At the same time, since the above-mentioned two types of compounds have a conjugated structure with a high degree of planarity, they can balance electrons and holes and improve the recombination rate of excitons. Ultimately, the device using the composition of the present invention as the light-emitting layer material is not only more efficient and longer-lasting than the prior art, but also has a significantly lower starting and stopping voltage. It should be noted that the inventors found that when one of the compound represented by formula (I) and the compound represented by formula (II) is used alone as the light-emitting layer material, the device performance obtained is significantly worse than when the two are used in combination. Therefore, it can be considered that there is a synergistic effect between the two.

[0021] It is worth noting that the fusion mode of indole and carbazole in formula (II) must be that the side at position 23 of indole is fused with the side at position 45 of carbazole and the nitrogen atoms are all on the outside, that is, the core part of formula (II) must be indole and [2,3-c] carbazole, and its isomers cannot achieve the above-mentioned technical effects of the present invention. This may be due to the change in HOMO energy level affecting the transmission of holes in the light-emitting layer. In addition, the parent core part of formula (I) has 1 There must not be any other heteroatoms besides the connected N atoms, otherwise the above technical effects of the present invention cannot be achieved. This may be because the introduction of heteroatoms destroys the balance between electrons and holes in the system.

[0022] In addition, an arylamino group refers to a group in which two or one of the H groups of an -NH2 group is replaced by an aryl group, wherein the aryl group includes a monocyclic aryl group and a condensed ring aryl group. The attachment point of the arylamino group in the present invention can be on the nitrogen or on a substituent on the nitrogen. In other words, the arylamino group can be connected to the rest of the molecule through the nitrogen or through a substituent.

[0023] It should be noted that the term "electron-deficient group" as used herein refers to a group whose substitution of a hydrogen atom on a benzene ring reduces the electron cloud density on the benzene ring. Such a group typically has a Hammett value greater than 0.6. The Hammett value characterizes the charge affinity of a particular group and is a measure of whether it is an electron-withdrawing group (positive Hammett value) or an electron-donating group (negative Hammett value). The Hammett equation is described in more detail in Thomas H. Lowry and Katheleen Schueller Richardson, "Mechanism and Theory in Organic Chemistry," New York, 1987, pp. 143-151, which is incorporated herein by reference. Such groups include, but are not limited to, triazine, pyrimidinyl, benzopyrimidinyl, benzopyridinyl, naphthyridinyl, phenanthroline, pyrazinyl, quinolyl, isoquinolyl, quinazolinyl, quinoxalinyl, pyridazinyl, and alkyl or aryl substituted groups. In addition, the carbon number of each group in this specification does not include the carbon number of the substituent when it has a substituent; aryl, arylene, heteroaryl, heteroarylene, etc. include not only monocyclic but also condensed rings.

[0024] In this invention, the expression Ca to Cb represents a group having a to b carbon atoms. Unless otherwise specified, this carbon number generally does not include the carbon atoms of substituents. In this invention, references to chemical elements encompass chemically identical isotopes. For example, the term "hydrogen" also encompasses chemically identical "deuterium" and "tritium." "Each independently" means that when there are multiple subjects, they may be the same or different.

[0025] R in the structural formula 1 The expression of substitution bond pointing to the center of the ring or crossing the aromatic ring indicates that the substitution position can be any possible position in the aromatic ring. The meaning of other substitution bond expressions in the structural formula is similar. 1 ~R 6 The number of each of the substituents is independently an integer greater than 1. Although this description does not limit the upper limit of the number of substituents, those skilled in the art know that the number of substituents will obviously not exceed the maximum permissible number of substitutions. For example, in formula (I), R 2 The upper limit of the number is obviously 4.

[0026] In the present invention, unless otherwise specified, the substituent and the group in which it is located are not fused. 3The description "optionally fused with the connected benzene ring to form a naphthalene ring structure" indicates that the formed fused ring structure contains a naphthalene ring structure, but does not limit the formed fused ring structure to be a naphthalene ring. For example, when the benzene ring before fusion is part of the naphthalene ring, 3 The result of fusion is an anthracene ring or a phenanthrene ring (the anthracene ring and the phenanthrene ring contain a naphthalene ring structure).

[0027] In the present specification, an alkyl group may be linear or branched, and unless otherwise specified, the number of carbon atoms is not particularly limited, but is preferably 1 to 20, more preferably 1 to 10. Specific examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, decyl, undecyl, dodecyl, and the like.

[0028] In the present specification, C1-C20 alkoxy is preferably C1~C10 alkoxy, and examples of the above-mentioned alkyl groups connected to -O- include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, etc., among which methoxy, ethoxy, propoxy, and more preferably methoxy are preferred.

[0029] In the present specification, the C3-C20 cycloalkyl group is preferably a C3-C10 cycloalkyl group, and examples thereof include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cyclodecyl.

[0030] In the present specification, examples of the C3-C10 heterocycloalkyl group include oxetanyl, 1,4-dioxanyl, and oxazolyl.

[0031] In the present specification, examples of the C6-C30 arylamino group include phenylamino, methylphenylamino, naphthylamino, anthrylamino, phenanthrenylamino, and biphenylamino groups.

[0032] In the present specification, examples of the C3-C30 heteroarylamino group include pyridylamino, pyrimidinylamino, and dibenzofuranylamino.

[0033] In this specification, aryl, arylene, heteroaryl, and heteroarylene include not only monocyclic but also condensed rings. Unless otherwise specified, aryl is not particularly limited, but preferably has 6 to 30 carbon atoms. Specific examples of aryl include phenyl, biphenyl, naphthyl, anthracenyl, phenanthrenyl, fluorenyl, triphenylenyl, indenyl, fluorenyl, fluoranthenyl, pyrenyl, perylenyl, Among them, phenyl and naphthyl are preferred, and phenyl is more preferred.

[0034] In this specification, a heteroaryl group is a heteroaryl group containing one or more of O, N, S, and Si as heteroatoms. Unless otherwise specified, the heteroaryl group is not particularly limited, but the number of carbon atoms is preferably 3-30. Specific examples of heteroaryl groups include thienyl, furyl, pyrrolyl, imidazolyl, thiazolyl, and oxazolyl. The C3-C30 heteroaryl group may be a nitrogen-containing heteroaryl group, an oxygen-containing heteroaryl group, or a sulfur-containing heteroaryl group, with nitrogen-containing heteroaryl groups being preferred. Specific examples include pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, quinolyl, isoquinolyl, naphthyridinyl, phthalazinyl, quinoxalinyl, quinazolinyl, phenanthridinyl, acridinyl, phenanthrolinyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, indolyl, benzimidazolyl, indazolyl, imidazopyridinyl, benzotriazolyl, carbazolyl, furyl, thienyl, oxazolyl, thiazolyl, isoxazolyl, isothiazolyl, oxazolyl, oxadiazolyl, thiadiazolyl, benzofuranyl, benzothiophenyl, benzoxazolyl, benzothiazolyl, benzisoxazolyl, benzisothiazolyl, benzoxadiazolyl, benzothiadiazolyl, dibenzofuranyl, dibenzothiophenyl, piperidinyl, pyrrolidinyl, piperazinyl, morpholinyl, phenazinyl, phenothiazinyl, phenoxazinyl, etc., among which pyridinyl, quinolinyl, dibenzofuranyl, dibenzothiophenyl, more preferably pyridinyl.

[0035] In this specification, the scope of arylene groups is similar to that of corresponding aryl groups, with the only difference being that one more hydrogen is removed from the corresponding aryl groups. The scope of heteroarylene groups is similar to that of corresponding heteroaryl groups, with the only difference being that one more hydrogen is removed from the corresponding heteroaryl groups.

[0036] In this specification, the "substituted or unsubstituted" group may be substituted with one substituent or multiple substituents. When there are multiple substituents, they can be selected from different substituents. When the same expression is involved in the present invention, it has the same meaning, and the selection range of the substituents is as shown above and will not be repeated one by one.

[0037] In the present invention, Ar 1 Preferably one selected from the following groups:

[0038]

[0039] Among them, R 11 and R 12 Each independently represents H, halogen, cyano, nitro, C1-C10 alkyl, C6-C20 aryl, C3-C20 heteroaryl, C3-C10 cycloalkyl, or C1-C10 alkoxy, R 11 、R 12 Optionally fused to the attached benzene ring, R 11 and R 12 The number of is each independently an integer greater than or equal to 1.

[0040] In the present invention, Ar 2 、Ar 3 Preferably, each is independently phenyl, naphthyl, anthracenyl, phenanthrenyl, triphenylenyl, dimethylfluorenyl, dibenzofuranyl, dibenzothiophenyl, diphenylpyrimidinyl, diphenyltriazolyl, or -NR 7 R 8 , where R 7 and R 8 Each is independently a phenyl group, a naphthyl group, a biphenyl group, or a naphthylphenyl group.

[0041] By adding Ar 1 ~Ar 3 When the above groups are selected, compared with other groups such as arylamino and heteroarylamino, the planarization degree of the above two types of compounds is further improved, which is conducive to further reducing the starting and stopping voltages of the organic electroluminescent device using the above composition. It is worth noting that in the present invention, Ar 1 ~Ar 3 In the case of a heteroaryl group, preferably the only heteroatom is nitrogen.

[0042] In the present invention, L 1 、L 2 、L 3 Preferably, each independently represents a single bond, a phenylene group, a naphthylene group, a biphenylene group, a quinoxalinylene group, a quinazolinylene group, or a pyridinylene group.

[0043] In the present invention, R 1 ~R 6 Preferably, each independently represents H, halogen, cyano, nitro, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C3-C20 heteroaryl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C1-C10 alkoxy, substituted or unsubstituted C6-C20 arylamino, or substituted or unsubstituted C3-C20 heteroarylamino, and R 3 Optionally fused with the attached benzene ring to form a naphthalene ring structure;

[0044] More preferably R 1 ~R 6 is H, fluorine, phenyl, biphenyl, naphthyl, or C6-C20 arylamino. 1 、R 2 、R 4 ~R 6 H, R 3 is H, phenyl, or fused with the connected benzene ring to form a naphthalene ring structure. 1 ~R 6When the above groups are used, compared with selecting other groups such as arylamino, heteroarylamino, alkoxy, etc., the planarization degree of the above two types of compounds is further improved, which is beneficial to further reduce the starting and ending voltages of the organic electroluminescent device using the above composition.

[0045] In the present invention, the compound represented by formula (I) is preferably selected from the following compounds:

[0046]

[0047]

[0048] In the present invention, the compound represented by formula (II) is preferably selected from the following compounds:

[0049]

[0050]

[0051] Another aspect of the present invention provides an organic light-emitting diode, characterized in that it comprises an anode, a cathode, and an organic layer located between the anode and the cathode; the organic layer comprises a functional layer and a light-emitting layer; and the light-emitting layer is formed by vapor deposition of the composition of the present invention comprising the compound represented by formula (I) and the compound represented by formula (II).

[0052] Another aspect of the present invention provides an organic electroluminescent device, characterized in that it comprises an anode, a cathode, and an organic layer located between the anode and the cathode; the organic layer comprises a functional layer and a light-emitting layer; and the light-emitting layer is formed by vapor deposition of the above-mentioned composition of the present invention comprising a compound represented by formula (I) and a compound represented by formula (II).

[0053] The functional layer may include one or more of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

[0054] In the organic light-emitting diode and organic electroluminescent device of the present invention, the weight ratio of the compound represented by formula (I) to the compound represented by formula (II) (I:II) is preferably 5% to 90%, more preferably 10% to 50%. Furthermore, the thickness of the light-emitting layer is preferably 10 nm to 55 nm, more preferably 15 nm to 45 nm.

[0055] Yet another aspect of the present invention provides a display panel, characterized in that it comprises the above-mentioned organic light emitting diode or the above-mentioned organic electroluminescent device.

[0056] Another aspect of the present invention provides a method for manufacturing an organic light-emitting diode and a display panel, characterized in that it includes the following steps: rate co-evaporating or pre-mixing the compound represented by formula (I) according to claim 1 or 9 and the compound represented by formula (II).

[0057] Another aspect of the present invention relates to the use of the above composition in an organic electroluminescent device, preferably the use of the composition as a light-emitting layer material in an organic electroluminescent device.

[0058] Effects of the Invention

[0059] The composition of the present invention, by simultaneously comprising a compound represented by formula (I) and a compound represented by formula (II), introduces an indolecarbazole with a relatively shallow HOMO energy level, thereby macro-regulating the transport of holes within the light-emitting layer. Furthermore, since both compounds have a highly planar conjugated structure, they can balance electrons and holes, increasing the recombination rate of excitons. Ultimately, devices using the composition of the present invention as a light-emitting layer material exhibit not only improved efficiency and lifespan compared to the prior art, but also significantly reduced start-up and drop-out voltages. OLED devices prepared using the compounds of the present invention have low start-up voltage, high luminous efficiency, and improved service life, meeting the current requirements of panel manufacturers for high-performance materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] [ Figure 1 ] Figure 1 Schematic diagram of the structure of the organic electroluminescent device of the present invention.

[0061] Explanation of symbols

[0062] 1 substrate

[0063] 2 Hole injection layer

[0064] 3 Hole transport layer

[0065] 4 Electron blocking layer

[0066] 5. Luminescent layer

[0067] 6 Electron Transport Layer

[0068] 7 Electron injection layer

[0069] 8 cathode

[0070] 9 External power supply DETAILED DESCRIPTION

[0071] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0072] Device Examples

[0073] Next, the organic electroluminescent device will be described in detail.

[0074] An OLED includes a first electrode, a second electrode, and an organic material layer between the electrodes. The organic material layer can be divided into multiple regions. For example, the organic material layer can include a hole transport region, a light-emitting layer, and an electron transport region.

[0075] In a specific embodiment, a substrate can be used below the first electrode or above the second electrode. The substrate is made of glass or a polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. In addition, the substrate used for the display can also be provided with thin film transistors (TFTs).

[0076] The first electrode can be formed by sputtering or depositing the material used as the first electrode on the substrate. When the first electrode serves as an anode, transparent conductive oxide materials such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), and any combination thereof can be used. When the first electrode serves as a cathode, metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag) can be used, as well as any combination thereof.

[0077] The organic material layer can be formed on the electrode by vacuum thermal evaporation, spin coating, printing, etc. The compound used as the organic material layer can be organic small molecules, organic macromolecules and polymers, and combinations thereof.

[0078] The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a single-layer hole transport layer (HTL), including single-layer hole transport layers containing only one compound and single-layer hole transport layers containing multiple compounds. The hole transport region can also be a multilayer structure comprising at least one of the following: a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL); wherein the HIL is located between the anode and the HTL, and the EBL is located between the HTL and the light-emitting layer.

[0079] The material of the hole transport region can be selected from, but not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives such as the compounds shown in HT-1 to HT-51 below; or any combination thereof.

[0080]

[0081]

[0082]

[0083] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound or a combination of multiple compounds. For example, the hole injection layer can use one or more of the compounds HT-1 to HT-51 described above, or one or more of the compounds HI-1 to HI-3 described below. Alternatively, one or more of the compounds HT-1 to HT-51 can be doped with one or more of the compounds HI-1 to HI-3 described below.

[0084]

[0085] The light-emitting layer includes a luminescent dye (i.e., a dopant) that can emit light at different wavelengths, and may also include a host material. The light-emitting layer can be a monochromatic light-emitting layer that emits a single color, such as red or green. Multiple monochromatic light-emitting layers of different colors can be arranged in a planar pattern according to a pixel pattern, or they can be stacked together to form a multi-color light-emitting layer. When stacked, the light-emitting layers of different colors can be separated or connected to each other. Alternatively, the light-emitting layer can be a single-color light-emitting layer that can simultaneously emit different colors, such as red and green.

[0086] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of GPD-1 to GPD-47 listed below.

[0087]

[0088]

[0089] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of RPD-1 to RPD-28 listed below.

[0090]

[0091]

[0092] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of YPD-1 to YPD-11 listed below.

[0093]

[0094] In one aspect of the present invention, an electron blocking layer (EBL) is located between the hole transport layer and the light emitting layer. The electron blocking layer can be one or more compounds selected from HT-1 to HT-51, but is not limited thereto.

[0095] The OLED organic material layer may also include an electron transport region between the light-emitting layer and the cathode. This region may be a single-layer electron transport layer (ETL), including those containing only one compound and those containing multiple compounds. The region may also be a multilayer structure comprising at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0096] In one aspect of the present invention, the electron transport layer material can be selected from, but not limited to, one or more combinations of ET-1 to ET-73 listed below.

[0097]

[0098]

[0099]

[0100] In one aspect of the present invention, a hole-blocking layer (HBL) is positioned between the electron-transporting layer and the light-emitting layer. The hole-blocking layer may be composed of, but is not limited to, one or more of the compounds ET-1 to ET-65 described above, or one or more of the compounds PH-1 to PH-46, or a mixture of, but not limited to, one or more of the compounds ET-1 to ET-65 and one or more of the compounds PH-1 to PH-46.

[0101] The device may further include an electron injection layer located between the electron transport layer and the cathode. Materials for the electron injection layer include, but are not limited to, one or more combinations of the following.

[0102] Liq, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca, Mg.

[0103] The technical effects and advantages of the present invention are demonstrated and verified below by applying the compound of the present invention to an organic electroluminescent device to test its actual performance.

[0104] The preparation process of the organic electroluminescent device in this embodiment 2 is as follows:

[0105] Glass plates coated with an ITO transparent conductive layer were ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in an acetone:ethanol mixed solvent, baked in a clean environment to completely remove water, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam.

[0106] The glass substrate with the anode was placed in a vacuum chamber and evacuated to <1×10⁻⁵ Pa. Vacuum-evaporated layers were then deposited on the anode layer in this order: a 10nm layer of a 97 / 3 w / w mixture of HT-4 and HI-3 as a hole injection layer, an 80nm layer of HT-4 as a hole transport layer, a 40nm layer of HT-48 as an electron blocking layer, a 30nm layer of a 100:50:3 w / w mixture of A8, B9, and RPD-10 as a light-emitting layer, a 25nm layer of a 50 / 50 w / w mixture of ET-61 and ET-57 as an electron transport layer, a 1nm layer of LiF as an electron injection layer, and a 150nm layer of aluminum as a cathode. The total deposition rate for all organic layers and LiF was controlled at 0.1nm / s, while the deposition rate for the metal electrode was controlled at 1nm / s.

[0107] Device Examples 1, 3, 4, 5, 6, and 7 were fabricated using the same method as in Example 2, except that A8-doped B9 in the light-emitting side layer was replaced by A7-doped B9, A45-doped B9, A41-doped B9, A7-doped B3, A7-doped B21, and A21-doped B9, respectively.

[0108] Device comparison examples 1 to 7 were made using the same method as device example 2, except that A8 doped with B9 in the light-emitting layer was replaced by A7, B9, A7 doped with R-1, A7 doped with R-2, R-3 doped with B9, R-5 doped with B9, A7 doped with R-4, etc.

[0109] Performance testing:

[0110] The organic electroluminescent device prepared by the above process was subjected to the following performance tests:

[0111] At the same brightness, the driving voltage and current efficiency of the organic electroluminescent devices prepared in Examples 1 to 7 and Comparative Examples 1 to 6, as well as the device life, were measured using a digital source meter and a luminance meter. Specifically, the voltage was increased at a rate of 0.1 V per second, and the luminance of the organic electroluminescent device was measured when it reached 3000 cd / m 2 The voltage at this time is the driving voltage, and the current density at this time is measured at the same time; the ratio of brightness to current density is the current efficiency;

[0112] The performance test results are shown in Table 1 and Table 2.

[0113] Table 1

[0114] Compound number Light-emitting layer materials and proportions Voltage (V) Current efficiency (cd / A) Comparative Example 1 A7 119％ 98％ Comparative Example 2 B9 103％ 90％ Comparative Example 3 A7:R-1=1:0.5 105％ 78％ Comparative Example 4 A7:R-2=1:0.5 96％ 85％ Comparative Example 5 R-3:B9=1:0.5 114％ 75％ Comparative Example 6 R-5:B9=1:0.5 118％ 77％ Comparative Example 7 A7:R-4=1:0.5 100％ 69％ Example 1 A7:B9=1:0.5 87％ 103％ Example 2 A8:B9=1:0.5 77％ 111％ Example 3 A45:B9=1:0.5 92％ 100％ Example 4 A41:B9=1:0.5 95％ 101％ Example 5 A7:B3=1:0.5 80％ 97％ Example 6 A7:B21=1:0.5 86％ 98％ Example 7 A21:B9=1:0.5 78％ 90％

[0115] The structural formulas of R-1 to R-5 are as follows:

[0116]

[0117] When A7 and B9 are used alone as the light-emitting layer material, the effect is obviously not as good as when the two are used in combination. Therefore, compared with the embodiment, the device voltage of Comparative Examples 1 and 2 is higher and the current efficiency is lower.

[0118] R-1, R-2, and R-4 are all indole and carbazole compounds, however, they are not indole and [2,3-c] carbazole compounds defined in the present invention. As mentioned above, the fusion mode of indole and carbazole in formula (II) of the present invention must be that the edge at position 23 of indole is fused with the edge at position 45 of carbazole and the nitrogen atoms are all on the outside, that is, the core part of formula (II) must be indole and [2,3-c] carbazole, and its isomers cannot achieve the technical effect of the present invention. Therefore, the comparative examples 3, 4, and 7 using the above three materials have higher device voltages and lower current efficiencies than the embodiments.

[0119] Although R-3 has a similar structure to the compound of formula (I) of the present invention, its heteroatom is not nitrogen, and the position of the triazine group attachment is also different. While R-5 has a nitrogen heteroatom, its parent nucleus is different from that of the compound of formula (I) of the present invention. Therefore, the device voltages of Comparative Examples 5 and 6 using these two materials are higher and the current efficiencies are lower than those of the examples.

[0120] The above results show that the composition of the present invention can be used in organic electroluminescent devices to effectively reduce the starting and ending voltages and improve the current efficiency, and is a main material for the light-emitting layer with good performance.

[0121] Table 2

[0122] Compound number Light-emitting layer materials and proportions Thickness of luminescent layer (nm) Voltage (V) Current efficiency (cd / A) Comparative Example 1-1 A1:B9=1:0.04 30 120％ 93％ Example 1-1 A1:B9=1:0.07 30 95％ 102％ Example 1-2 A1:B9=1:0.3 30 93％ 106％ Examples 1-3 A1:B9=1:0.5 30 87％ 113％ Examples 1-4 A1:B9=1:0.7 30 95％ 97％ Comparative Example 1-2 A1:B9=1:0.91 30 108％ 88％ Comparative Example 2-1 A7:B9=1:0.5 8 100％ 78％ Example 2-1 A7:B9=1:0.5 12 90％ 92％ Example 2-2 A7:B9=1:0.5 18 89％ 108％ Example 2-3 A7:B9=1:0.5 42 93％ 115％ Examples 2-4 A7:B9=1:0.5 53 99％ 104％ Comparative Example 2-2 A7:B9=1:0.5 57 117％ 101％

[0123] The above results indicate that when the composition of the present invention is used in an organic electroluminescent device, the weight ratio of the compound represented by formula (I) to the compound represented by formula (II) (I):(II) should be 5%-90%, preferably 10%-50%. In addition, the thickness of the light-emitting layer should be 10 nm-55 nm, preferably 15 nm-45 nm.

[0124] Although the present invention has been described in conjunction with the embodiments, the present invention is not limited to the above embodiments. It should be understood that under the guidance of the concept of the present invention, those skilled in the art may make various modifications and improvements. The appended claims summarize the scope of the invention.

Claims

1. A composition, characterized in that Comprising a compound represented by formula (I) and a compound represented by formula (II): Among them, R 1 ~R 6 Each independently represents H, halogen, cyano, nitro, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C6-C30 arylamino, or substituted or unsubstituted C3-C30 heteroarylamino, R 1 ~R 6 The number of each is independently an integer greater than 1; 3 Optionally fused with the attached benzene ring to form a naphthalene ring structure, L 1 , L 2 , L 3 Each is independently a single bond, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C3-C20 heteroarylene group; Ar 1 、Ar 2 、Ar 3 Each is independently a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C6-C20 heteroaryl group, a substituted or unsubstituted C6-C20 arylamino group, or a substituted or unsubstituted C3-C20 heteroarylamino group, at least one of which is an electron-deficient group; When the above-mentioned substituted or unsubstituted group has a substituent, the substituent is selected from one or a combination of two or more of halogen, cyano, nitro, amino, C1-C10 alkyl, C1-C10 alkoxy, C3-C10 cycloalkyl, C3-C10 heterocycloalkyl, C6-C20 aryl, and C3-C20 heteroaryl.

2. The composition according to claim 1, characterized in that Ar 1 One selected from the following groups: Among them, R 11 and R 12 Each independently represents H, halogen, cyano, nitro, C1-C10 alkyl, C6-C20 aryl, C3-C20 heteroaryl, C3-C10 cycloalkyl, or C1-C10 alkoxy, R 11 、R 12 Optionally fused to the attached benzene ring, R 11 and R 12 The number of is each independently an integer greater than or equal to 1.

3. The composition according to claim 1, characterized in that Ar 2 、Ar 3 Each is independently phenyl, naphthyl, anthracenyl, phenanthrenyl, triphenylenyl, dimethylfluorenyl, dibenzofuranyl, dibenzothiophenyl, diphenylpyrimidinyl, diphenyltriazolyl, or -NR 7 R 8 , where R 7 and R 8 Each is independently a phenyl group, a naphthyl group, a biphenyl group, or a naphthylphenyl group.

4. The composition according to claim 1, characterized in that L 1 , L 2 , L 3 Each is independently a single bond, a phenylene group, a naphthylene group, a biphenylene group, a quinoxalinylene group, a quinazolinylene group, or a pyridinylene group.

5. The composition according to claim 1, characterized in that R 1 ~R 6 Each independently represents H, halogen, cyano, nitro, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C3-C20 heteroaryl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C1-C10 alkoxy, substituted or unsubstituted C6-C20 arylamino, or substituted or unsubstituted C3-C20 heteroarylamino, R 3 Optionally, it is fused to the attached benzene ring to form a naphthalene ring structure.

6. The composition according to claim 1, characterized in that R 1 ~R 6 It is H, fluorine, phenyl, biphenyl, naphthyl, or C6-C20 arylamino.

7. The composition according to claim 1, characterized in that R 1 、R 2 、R 4 ~R 6 H, R 3 It is H, a phenyl group, or fused with the connected benzene ring to form a naphthalene ring structure.

8. The composition according to claim 1, characterized in that The compound represented by formula (I) is selected from the following compounds:

9. The composition according to claim 1, characterized in that The compound represented by formula (II) is selected from the following compounds:

10. An organic electroluminescent device, characterized in that: comprising an anode, a cathode, and an organic layer between the anode and the cathode; The organic layer comprises a functional layer and a light-emitting layer; The light-emitting layer is formed by vapor deposition of the composition according to any one of claims 1 to 9.

11. The organic electroluminescent device according to claim 10, characterized in that: The weight ratio of the compound represented by formula (I) to the compound represented by formula (II) is 5% to 90% (I): (II).

12. The organic electroluminescent device according to claim 11, characterized in that: The weight ratio of the compound represented by formula (I) to the compound represented by formula (II) is 10% to 50% (I): (II).

13. The organic electroluminescent device according to claim 10, characterized in that: The thickness of the light-emitting layer is 10nm-55nm.

14. The organic electroluminescent device according to claim 13, characterized in that: The thickness of the light-emitting layer is 15nm-45nm.

15. Use of the composition according to any one of claims 1 to 9 in an organic electroluminescent device, wherein the composition is used as a light-emitting layer material in the organic electroluminescent device.

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