Light-emitting auxiliary material, preparation method thereof and organic electroluminescent device

Abstract

The application discloses a light-emitting auxiliary material and a preparation method thereof, and belongs to the field of organic photoelectric electroluminescent materials. The light-emitting auxiliary material provided by the application is based on benzonaphthofuran, a triarylamine group is connected to naphthalene, and a 9-phenyl-9H-carbazole is connected to the benzene on the other side. Compared with existing organic electroluminescent devices, the light-emitting auxiliary material can improve the service life of the device and significantly improve the light-emitting efficiency while maintaining the driving voltage basically unchanged. The application further provides an organic electroluminescent device comprising the light-emitting auxiliary material. Compared with the prior art, the organic electroluminescent device has the technical effects of improving the service life of the device and significantly improving the light-emitting efficiency while maintaining the driving voltage basically unchanged.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of organic electroluminescent materials, more particularly to a light-emitting auxiliary material, a preparation method thereof and an organic electroluminescent device. BACKGROUND

[0002] Organic electroluminescence (OLED) is a type of self-luminescent display element, and the display has the advantages of high brightness, high resolution, wide viewing angle, low power consumption, and high response speed. Generally speaking, organic electroluminescence refers to the phenomenon of converting electrical energy into light energy by using organic substances. An organic light-emitting element using the organic light-emitting phenomenon generally has a structure including an anode and a cathode and an organic layer located therebetween. For example, a hole injection layer (HIL), a hole transport layer (HTL), a light-emitting layer, an electron transport layer (ETL), and an electron injection layer (EIL).

[0003] In order to solve the problems of service life and efficiency, a light-emitting auxiliary layer (multi-layer hole transport layer) is usually added between the hole transport layer and the light-emitting layer. The light-emitting auxiliary layer mainly plays the role of assisting the hole transport layer, and is therefore also called the second hole transport layer. The light-emitting auxiliary layer can smoothly move the holes transferred from the anode to the light-emitting layer, and can block the electrons transferred from the cathode to limit the electrons in the light-emitting layer, reduce the potential barrier between the hole transport layer and the light-emitting layer, reduce the driving voltage of the organic electroluminescent device, further increase the utilization rate of holes, and thus improve the light-emitting efficiency and service life of the device.

[0004] However, there are few materials that can form a light-emitting auxiliary layer and have excellent device performance. In particular, the service life and light-emitting efficiency of OLEDs are not significantly improved, so it is particularly important to develop higher-performance organic functional materials to meet the requirements of panel manufacturing companies.

[0005] Therefore, how to provide a light-emitting auxiliary material with long service life and high light-emitting efficiency, a preparation method thereof and an organic electroluminescent device is a technical problem that those skilled in the art urgently need to solve. SUMMARY

[0006] Therefore, the present application provides a light-emitting auxiliary material and a preparation method thereof. The blue light-emitting auxiliary material provided by the present application is based on benzofluoro[3,2-b]naphtho[2,3-d]furan, a triarylamine group is connected to the naphthalene, and a 9-phenyl-9H-carbazole is connected to the other benzene. Compared with existing organic electroluminescent devices, the device service life can be improved and the light-emitting efficiency can be significantly improved while maintaining the driving voltage substantially unchanged.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] A light-emitting auxiliary material, the structure general formula is shown as formula I:

[0009]

[0010] in,

[0011] Ar fuses with the adjacent benzene ring;

[0012] Ar is an independent aryl group selected from substituted or unsubstituted C6-C30;

[0013] Ar1-Ar2 are independently selected from substituted or unsubstituted C3-C30 cycloalkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted 3-30-membered heteroaryl groups.

[0014] Furthermore, Ar1-Ar2 are independently selected from substituted or unsubstituted C3-C18 cycloalkyl groups, substituted or unsubstituted C6-C18 aryl groups, and substituted or unsubstituted 3- to 24-membered heteroaryl groups.

[0015] Furthermore, when Ar1 and Ar2 are selected from substituted or unsubstituted C3-C18 cycloalkyl groups, they are preferably cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 3-methylcyclopentyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl, 2,3-dimethylcyclopentyl, bicyclo[3.1.1]heptyl, and adamantyl.

[0016] Furthermore, when Ar1 and Ar2 are selected from substituted or unsubstituted C6-C18 aryl groups, they are preferably phenyl, biphenyl, terphenyl, naphthyl, binatyl, phenylnaphthyl, naphthylphenyl, phenyl terphenyl, fluorenyl, dimethylfluorenyl, diphenylfluorenyl, benzo[a]fluorenyl, dibenzo[a]fluorenyl, phenanthrene, phenylphenanthrene, anthracene, indene, triphenylene, pyrene, perylene, trefyl, naphthyl, fluoranyl, spirodifluorenyl, azulel, methylphenyl, ethylphenyl, methoxyphenyl, cyanophenyl;

[0017] Further, Ar1, Ar2 are selected from substituted or unsubstituted 3- to 24-membered heteroaryl, preferably furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, furazanyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, benzofuranyl, benzothienyl, isobenzofuranyl, dibenzofuranyl, dibenzothienyl, benzoimidazolyl, benzothiazolyl, benzoisothiazolyl, benzoisoxazolyl, benzoaxazolyl, isoindolyl, indolyl, benzoindolyl, indazolyl, benzothiadiazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, benzoquinazolinyl, quinoxalinyl, benzoquinoxalinyl, naphthidinyl, carbazolyl, benzocarbazolyl, diphenoxazinyl, phenoxazinyl, phenanthridinyl, benzodioxolyl, and dihydroacridinyl.

[0018] Further, Ar1, Ar2 are each independently selected from phenyl, naphthyl, phenanthryl, methylphenyl, ethylphenyl, cyanophenyl, methoxyphenyl, phenylpyridinyl, phenylpyrimidinyl, biphenyl, terphenyl, phenylnaphthyl, dibenzofuranyl, dibenzothienyl, carbazolyl, 9-phenyl-9H-carbazolyl, diphenylfluorenyl, dimethylfluorenyl, cyclopentyl, cyclohexyl;

[0019] Further, Formula I includes the following structures:

[0020]

[0021] In the above technical solutions,

[0022] “Substituted or unsubstituted” means substituted with one, two, or more substituents selected from deuterium; a halogen group; a nitrile group; a hydroxyl group; a carbonyl group; an ester group; a silyl group; a boron group; a C1-C30 alkyl group; a C3-C30 cycloalkyl group; an alkoxy group; a C6-C30 aryl group; a 3- to 30-membered heteroaryl group, or a substituent connected with two or more substituents from the above-mentioned substituents, or no substituent.

[0023] Cycloalkyl refers to monocyclic, polycyclic, and spirocyclic alkyl groups;

[0024] Aryl refers to monocyclic aromatic hydrocarbon groups and polycyclic aromatic ring systems, which can have two or more rings with two carbons common to two adjacent rings (the rings are “fused”);

[0025] Heteroaryl includes monocyclic aromatic groups and polycyclic aromatic ring systems with at least one heteroatom, including but not limited to O, S, N, P, B, Si, and Se;

[0026] Further, Formula I includes the following structures:

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033] The preparation method of the light-emitting auxiliary material described above comprises the following steps:

[0034] The synthetic route is as follows:

[0035]

[0036] wherein Hal1, Hal2 are selected from Cl, Br, I; R' is

[0037] Ar1-Ar2, Ar are the same as the above range;

[0038] The preparation method comprises:

[0039] (1) N2-protected, the reactant A-I (1.0 eq), the reactant B-I (1.0-1.4 eq), the palladium catalyst (0.01-0.1 eq) and the base (2.0-4.0 eq) are added to the mixed solvent of toluene, ethanol, water respectively, heated to 80-100℃, reacted for 8-14h, hot filtered with diatomite, remove the salt and catalyst, the filtrate is cooled to room temperature, the solvent is removed by using a rotary evaporator, the obtained solid is dried and then passed through a silica gel funnel, using dichloromethane: petroleum ether (volume ratio 1:2-6) as the developing agent, the filtrate is removed by using a rotary evaporator, the obtained solid is dried, and the intermediate C-I is obtained.

[0040] (2) After adding the intermediate C-I (1.0 eq) and the reactant D-I (1.0-1.5 eq) dissolved in xylene in a reaction vessel, a palladium catalyst (0.01-0.1 eq), a phosphorus ligand (0.01-1.0 eq), and a base (2.0 eq-3.0 eq) are added under nitrogen protection; after addition, the reaction temperature is slowly increased to 120-140℃, and the mixture is stirred for 8-14h; the remaining material is purified by column chromatography to obtain formula I.

[0041] or,

[0042] The synthetic route is as follows:

[0043]

[0044] wherein, Hal1, Hal2 are selected from Cl, Br, I; R' is

[0045] Ar1-Ar2, Ar are the same as the above range;

[0046] The preparation method comprises:

[0047] (1) After adding reactant A-I (1.0 eq) and reactant B-I (1.0-1.5 eq) dissolved in toluene in a reaction container, a palladium catalyst (0.01-0.1 eq), a phosphine ligand (0.01-1.0 eq), and a base (2.0-3.0 eq) are added under nitrogen protection; after the addition, the reaction temperature is slowly increased to 85-95°C, and the mixture is stirred for 6-14 h; the remaining material is purified by column chromatography to obtain intermediate C-I.

[0048] (2) Under N2 protection, intermediate C-I (1.0 eq), reactant D-I (1.0-1.5 eq), a palladium catalyst (0.01-0.1 eq), a phosphine ligand (0.01-1.0 eq), and a base (2.0-3.0 eq) are added to a mixed solvent of toluene, ethanol, and water, respectively; the temperature is increased to 80-90°C, and the reaction is carried out for 6-12 h; the remaining material is purified by column chromatography; the filtrate is subjected to solvent removal by a rotary evaporator; the obtained solid is dried to obtain compound I.

[0049] wherein,

[0050] The palladium catalyst can be Pd2(dba)3, Pd(PPh3)4, PdCl2, PdCl2(dppf), Pd(OAc)2, Pd(PPh3)2Cl2, or NiCl2(dppf).

[0051] The phosphine ligand can be P(t-Bu)3, X-phos, PET3, PMe3, PPh3, KPPh2, or P(t-Bu)2Cl.

[0052] The base can be K2CO3, K3PO4, Na2CO3, CsF, Cs2CO3, or t-BuONa.

[0053] It is another object of the present application to provide an organic electroluminescent device which can have a structure including a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting auxiliary layer, a light emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, a cap layer, and the like as organic layers. However, the structure of the organic light emitting element is not limited thereto, and can include a smaller or larger number of organic layers.

[0054] According to one embodiment of the present specification, the compound represented by Formula I is prepared as a light-emitting auxiliary layer material.

[0055] As for the compound represented by Formula I described above, in the production of the organic light-emitting element, an organic layer can be formed by a vacuum evaporation method or a solution coating method. The solution coating method includes, but is not limited to, a spin coating method, a dip coating method, a blade coating method, an inkjet printing method, a screen printing method, a spray method, and a roll coating method.

[0056] The organic light-emitting element of the present application can be a top emission type, a bottom emission type, or a dual emission type, depending on the materials used.

[0057] The device described in the present application can be used for an organic light-emitting device, including but not limited to a flat panel display, a computer monitor, a medical monitor, a television, a billboard, a lamp for internal or external lighting and / or signaling, a heads-up display, a fully or partially transparent display, a flexible display, a laser printer, a telephone, a cell phone, a tablet, a photo album, a personal digital assistant (PDA), a wearable device, a notebook computer, a digital camera, a video camera, a viewfinder, a micro display, a three-dimensional display, a virtual reality or augmented reality display, a vehicle, a video wall including multiple displays tiled together, a theater or venue screen, a light therapy device, and a sign.

[0058] As an anode material, a material having a large work function is generally preferred in order to enable smooth injection of holes into the organic layer. Specific examples of the anode material that can be used in the present application include metals such as vanadium, chromium, copper, zinc, and gold, or alloys thereof; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of a metal and an oxide such as ZnO:Al or SnO2:Sb; conductive polymers such as polypyrrole and polyaniline; and the like.

[0059] The hole injection layer is preferably a p-doped hole injection layer, which means a hole injection layer doped with a p-dopant. The p-dopant is a material that imparts p-type semiconductor properties. The p-type semiconductor properties mean the property of injecting or transporting holes at the HOMO level, i.e., the property of a material having a high hole conductivity.

[0060] The hole transport material is a material that can receive holes from the anode or the hole injection layer and transport the holes to the light-emitting layer, and is a material having a high hole mobility. The hole transport material can be selected from arylamine derivatives, conductive polymers, and block copolymers having both a conjugated portion and a non-conjugated portion, and the like.

[0061] An emission auxiliary layer (a multi-hole transport layer) is added between the hole transport layer and the emission layer. The emission auxiliary layer mainly functions as an auxiliary hole transport layer, and is sometimes referred to as a second hole transport layer. The emission auxiliary layer enables smooth movement of holes transferred from the anode to the emission layer, and can block electrons transferred from the cathode to confine the electrons within the emission layer, reduce the potential barrier between the hole transport layer and the emission layer, lower the driving voltage of the organic electroluminescent device, further increase the utilization rate of holes, and thus improve the emission efficiency and the lifespan of the device.

[0062] The emission substance of the emission layer is a substance capable of receiving holes and electrons from the hole transport layer and the electron transport layer, respectively, and causing the holes and the electrons to combine to emit light in the visible region, and is preferably a substance having high quantum efficiency for fluorescence or phosphorescence.

[0063] The emission layer can include a host material and a dopant material.

[0064] The mass ratio of the host material to the dopant material is 90-99.5:0.5-10.

[0065] The host material is an aromatic condensed ring derivative or a heterocyclic compound, etc. Specifically, as the aromatic condensed ring derivative, there are anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentacene derivatives, phenanthrene compounds, fluoranthene compounds, etc., and as the heterocyclic compound, there are carbazole derivatives, diphenyl furan derivatives, pyrimidine derivatives, etc.

[0066] The dopant material of the present application includes fluorescent dopants and phosphorescent dopants. It can be selected from aromatic amine derivatives, styryl amine compounds, boron complexes, fluoranthene compounds, metal complexes, etc.

[0067] The electron transport layer can function to facilitate electron transport. The electron transport material is a material that advantageously receives electrons from the cathode and transports the electrons to the emission layer, and is preferably a material having high electron mobility. The electron transport layer can include at least one of an electron buffer layer, a hole blocking layer, an electron transport layer, and an electron injection layer, and preferably at least one of the electron transport layer and the electron injection layer.

[0068] The electron injection layer can function to facilitate electron injection. It has the ability to transport electrons, and prevents excitons generated in the emission layer from migrating to the hole injection layer. The material of the electron injection layer includes oxazoles, oxadiazoles, triazoles, imidazoles, perylene tetracarboxylic acid, fluorenyl methanes, anthracenes, and derivatives thereof, metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, ytterbium, etc., or alloys thereof, metal complexes, nitrogen-containing 5-membered ring derivatives, etc., but is not limited thereto.

[0069] The cathode is preferably a material having a small work function to allow easy injection of electrons into the organic material layer, which preferably has a layer thickness of between 0.5 and 5 nm. The cathode material, which is preferably a material having a small work function in order to allow easy injection of electrons into the organic material layer, is, for example, a metal such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or an alloy thereof, such as LiF / Al or LiO2 / Al, a multi-layered structure material such as Mg / Ag, or the like.

[0070] There is no particular restriction on the materials for other layers in the OLED device, except that the light-emitting auxiliary layer disclosed herein comprises Formula I. Existing hole injection materials, hole transport materials, hole transport auxiliary materials, dopant materials, hole blocking layer materials, electron transport layer materials, and electron injection materials can be used.

[0071] The principles involved in the present application are as follows:

[0072] A series of palladium-catalyzed coupling reactions are carried out in the present application, which on the one hand takes advantage of the difference that the activity of Br is greater than that of Cl, and on the other hand controls the reaction site by controlling the reaction conditions, and purifies the reaction by column chromatography or silica gel funnel to remove by-products to obtain the target compound. Reference is made to the following well-known knowledge:

[0073] Transition Metal Organometallic Chemistry (6th Edition), Robert H. Crabtree, Publisher: Shanghai East China University of Technology Press, Publication Time: 2017-09-00, ISBN: 978-7-5628-5111-0, Page 388.

[0074] Organic Chemistry and Optoelectronic Material Experiment Tutorial, Chen Runfeng, Publisher: Southeast University Press, Publication Time: 2019-11-00, ISBN: 9787564184230, Page 174.

[0075] As can be known from the above technical solutions, compared with the prior art, the present application has the following beneficial effects: the blue light-emitting auxiliary material provided by the present application is based on benzofluoranthene, with a triarylamine group connected to naphthalene and a 9-phenyl-9H-carbazole connected to the other benzene. Benzofluoranthene retains the advantage of high triplet energy level of dibenzofuran, and on this basis increases the conjugated plane, increases the hole transport rate, and avoids the extension of the conjugated plane, which has the effect of improving device efficiency. Compared with existing organic electroluminescent devices, the device can improve the device lifetime and significantly improve the luminous efficiency while maintaining the driving voltage substantially unchanged. BRIEF DESCRIPTION OF DRAWINGS

[0076] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are only a part of the present application, and other drawings can be obtained by those of ordinary skill in the art without creative effort on the basis of the drawings provided.

[0077] Figure 1 NMR of intermediate C-1;

[0078] Figure 2 NMR of compound 1. DETAILED DESCRIPTION

[0079] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort fall within the scope of the present application.

[0080] Example 1: synthesis of compound 1

[0081]

[0082] CAS: reactant A-1: 2472861-95-1

[0083] CAS: reactant D-1: 1189047-28-6

[0084] After adding reactant A-1 (50 mmol) and reactant B-1 (55 mmol) dissolved in toluene in a reaction vessel, Pd2(dba)3 (0.5 mmol), P(t-Bu)3 (1 mmol), t-BuONa (110 mmol) were added under nitrogen protection; after addition, the reaction temperature was slowly warmed to 90°C, and the mixture was stirred for 8 h, the remaining material was purified by column chromatography to obtain intermediate C-1 (21.17 g, yield: 74%, test value MS (ESI, m / Z): [M+H] + = 572.33, NMR of intermediate C-1 hydrogen spectrum as Figure 1 shown).

[0085] Intermediate C-1 (30 mmol), reactant D-1 (36 mmol), palladium acetate (Pd(OAc)2) (0.6 mmol) and 2-cyclohexyl-2,4,6-triisopropylbiphenyl (X-Phos) (1.5 mmol), cesium carbonate (Cs2CO3) (63 mmol) were added to a mixture solvent of toluene, ethanol, water (180 mL:60 mL:60 mL) under N2protection, and the reaction was heated to 80 °C for 10 h. The residual material was purified by column chromatography, and the filtrate was concentrated by a rotary evaporator. The obtained solid was dried to obtain compound 1 (16.36 g, yield: 70%, test value MS (ESI, m / Z): [M+H]+= 779.12, compound 1 nuclear magnetic resonance hydrogen spectrum as shown in Figure 2

[0086] Characterization:

[0087] HPLC purity: >99.8%.

[0088] Elemental analysis:

[0089] Theoretical value: C, 89.43; H, 4.92; N, 3.60; O, 2.05

[0090] Test value: C, 89.26; H, 5.04; N, 3.65; O, 2.10

[0091] Example 2: Synthesis of compound 40

[0092]

[0093] CAS: Reactant A-40: 2472861-93-9

[0094] Reactant A-40 (50 mmol) and reactant B-40 (55 mmol) were dissolved in toluene in a reaction vessel, and Pd2(dba)3 (0.5 mmol), P(t-Bu)3 (1 mmol), t-BuONa (110 mmol) were added under nitrogen protection. After addition, the reaction temperature was slowly warmed to 90 °C, and the mixture was stirred for 8 h. The residual material was purified by column chromatography to obtain intermediate C-40 (18.58 g, yield: 68%, test value MS (ESI, m / Z): [M+H] + = 546.36).

[0095] ​Under N2protection, intermediate C-40 (30 mmol), reactant D-40 (36 mmol), palladium acetate (Pd(OAc)2) (0.6 mmol) and 2-cyclohexyl-2,4,6-triisopropyl biphenyl (X-Phos) (1.5 mmol), cesium carbonate (Cs2CO3) (63 mmol) were added into a mixed solvent of toluene, ethanol, water (180 mL:60 mL:60 mL) respectively, heated to 80 °C, reacted for 10 h, the residual material was purified by column chromatography, the filtrate was removed by rotary evaporator, the obtained solid was dried, to obtain compound 1 (16.49 g, yield: 73%, test value MS (ESI, m / Z): [M+H]+= 753.17).

[0096] Characterization:

[0097] HPLC purity: >99.8%.

[0098] Elemental analysis:

[0099] Theoretical value: C, 89.33; H, 4.82; N, 3.72; O, 2.12

[0100] Test value: C, 89.14; H, 4.95; N, 3.78; O, 2.19

[0101] Example 3: synthesis of compound 105

[0102]

[0103] CAS: reactant A-105: 2692602-69-8

[0104] Under N2protection, reactant A-105 (50 mmol), reactant B-105 (60 mmol), tetrakis(triphenylphosphine)palladium (0.5 mmol) and potassium carbonate (110 mmol) were added into a mixed solvent of toluene, ethanol, water (150 mL:50 mL:50 mL) respectively, heated to 95 °C, reacted for 10 h, hot suction filtration was used to remove the salt and catalyst, after the filtrate was cooled to room temperature, the solvent was removed by rotary evaporator, the obtained solid was dried, then passed through a silica gel funnel, dichloromethane: petroleum ether (volume ratio 1:6) was used as developing agent, the filtrate was removed by rotary evaporator, the obtained solid was dried, to obtain intermediate C-105 (16.31 g, yield: 66%, Mw: 494.30).

[0105] After adding intermediate C-105 (30 mmol) and reactant D-105 (33 mmol) dissolved in xylene (180 mL) in a reaction vessel, Pd(OAc)2(1.5 mmol), X-Phos (3.6 mmol), t-BuONa (63 mmol) were added under nitrogen protection; after addition, the reaction temperature was slowly warmed to 135°C, and the mixture was stirred for 10 h; the remaining material was purified by column chromatography to obtain compound 105 (18.00 g, yield: 72%, test value MS (ESI, m / Z): [M+H] + = 833.24).

[0106] Characterization:

[0107] HPLC purity: >99.8%.

[0108] Elemental analysis:

[0109] Theoretical value: C, 87.96; H, 4.84; N, 3.36; O, 3.84

[0110] Test value: C, 87.81; H, 4.97; N, 3.40; O, 3.88

[0111] Example 4-31

[0112] The synthesis of the following compounds was completed according to the synthesis method of Reference Examples 1 to 3, and the molecular formula and mass spectrum thereof are shown in Table 1 below.

[0113] Table 1 Molecular formula and mass spectrum

[0114]

[0115]

[0116] In addition, it should be noted that other compounds of the present application can be obtained according to the synthesis method of the above-mentioned examples, and therefore will not be listed one by one here.

[0117] The present application provides an organic electroluminescent device, which can have a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer

[0118] Application Example 1 Preparation of an organic electroluminescent device:

[0119] a、ITO anode: ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 150 nm is cleaned in distilled water for 2 times, ultrasonic washing for 30 min, and then repeatedly cleaned in distilled water for 2 times, ultrasonic washing for 10 min. After washing, the substrate is baked in a vacuum oven at 220°C for 2 hours, and then cooled to room temperature for use. The substrate is used as an anode, and a device process is performed by using an evaporation machine to evaporate other functional layers on the substrate.

[0120] b、HIL (hole injection layer): HT and P-dopant are vacuum evaporated at an evaporation rate of 0.1 nm / s, and the chemical formula is shown below. The evaporation rate ratio of HT and P-dopant is 98:2, and the thickness is 10 nm.

[0121] c、HTL (hole transport layer): HT is vacuum evaporated on the hole injection layer at an evaporation rate of 0.1 nm / s to form a 120 nm thick hole transport layer.

[0122] d、Prime (light emitting auxiliary layer): the compound of the present application is vacuum evaporated on the hole transport layer at an evaporation rate of 0.1 nm / s to form a 10 nm thick light emitting auxiliary layer.

[0123] e、EML (light emitting layer): then, the host material (Host) and the doping material (Dopant) are vacuum evaporated on the light emitting auxiliary layer at an evaporation rate of 0.1 nm / s to form a 25 nm thick light emitting layer, and the chemical formula of the Host and the Dopant is shown below. The evaporation rate ratio of the Host and the Dopant is 97:3.

[0124] f、HB (hole blocking layer): the hole blocking layer is vacuum evaporated at an evaporation rate of 0.1 nm / s to form a 5.0 nm thick hole blocking layer.

[0125] g、ETL (electron transport layer): ET and Liq are vacuum evaporated at an evaporation rate of 0.1 nm / s to form a 35 nm thick electron transport layer. The evaporation rate ratio of ET and Liq is 50:50.

[0126] h、EIL (electron injection layer): Yb film layer is evaporated at an evaporation rate of 0.1 nm / s to form a 1.0 nm thick electron injection layer.

[0127] i、cathode: magnesium and silver are evaporated at an evaporation rate ratio of 1:9 to form an 18 nm thick cathode, thereby obtaining an OLED device.

[0128] j、light extraction layer:​​​​​​​​ The evaporation rate of the CPL was 0.5 A / s, and the thickness of the CPL was 70 nm.

[0129] k, the substrate on which the evaporation is completed is packaged. First, the cleaned cover plate is coated with UV glue by using a gluing device, then the coated cover plate is moved to the pressing section, the substrate on which the evaporation is completed is placed on the upper end of the cover plate, and finally the substrate and the cover plate are bonded under the action of the bonding device, and the UV glue is simultaneously cured by light.

[0130] Device structure:

[0131] ITO / Ag / ITO / HT:P-dopant (10 nm, 2%) / HT (120 nm) / prime (compound of the application) (10 nm) / Host:Dopant (25 nm, 3%) / HB (5 nm) / ET:Liq (35 nm, 50%) / Yb (1 nm) / Mg:Ag (18 nm, 1:9) / CPL (70 nm).

[0132]

[0133] Application Example 2-31

[0134] The organic electroluminescence device of Application Example 2-31 is prepared according to the above preparation method of the organic electroluminescence device, except that the compound 1 in Application Example 1 is replaced by the corresponding compound in Example 2-31 respectively to form a light-emitting auxiliary layer.

[0135] Comparative Example 1

[0136] The organic electroluminescence device is prepared according to the above preparation method of the organic electroluminescence device, except that the compound 1 in Application Example 1 is replaced by Comparative Compound 1, wherein the structural formula of Comparative Compound 1 is as follows:

[0137] Comparative Example 2

[0138] The organic electroluminescence device is prepared according to the above preparation method of the organic electroluminescence device, except that the compound 1 in Application Example 1 is replaced by Comparative Compound 2, wherein the structural formula of Comparative Compound 2 is as follows:

[0139] Comparative Example 3

[0140] The organic electroluminescence device is prepared according to the above preparation method of the organic electroluminescence device, except that the compound 1 in Application Example 1 is replaced by Comparative Compound 3, wherein the structural formula of Comparative Compound 3 is as follows:

[0141] Comparative Example 4

[0142] Organic electroluminescent devices were prepared according to the above-described method, except that compound 1 in Application Example 1 was replaced with comparative compound 4, wherein the structural formula of comparative compound 4 is as follows:

[0143] Comparative Example 5

[0144] An organic electroluminescent device was prepared according to the above-described method, except that compound 1 in Application Example 1 was replaced with comparative compound 5, wherein the structural formula of comparative compound 5 is as follows:

[0145] Comparative Example 6

[0146] An organic electroluminescent device was prepared according to the above-described method, except that compound 1 in Application Example 1 was replaced with comparative compound 6, wherein the structural formula of comparative compound 6 is as follows:

[0147] Comparative Example 7

[0148] An organic electroluminescent device was prepared according to the above-described method, except that compound 1 in Application Example 1 was replaced with comparative compound 7, wherein the structural formula of comparative compound 7 is as follows:

[0149]

[0150] The driving voltage, luminous efficiency, BI value, and lifetime of the organic electroluminescent devices obtained in Examples 1-31 and Comparative Examples 1-7 were characterized at a brightness of 1000 nits. The test results are shown in Table 2 below:

[0151] Table 2. Results of luminous properties test (luminance value 1000 nits)

[0152]

[0153]

[0154]

[0155] Those skilled in the art will understand that the energy levels of the luminescent auxiliary layer are matched with those of the luminescent layer and the hole transport layer, and the target values ​​that need to be adjusted differ for different luminescent layers. The differences are significant for luminescent layers of different colors. Even for the same blue light, there are significant differences depending on the host and dopant materials.

[0156] The blue light organic electroluminescent device is affected by the microcavity effect, and the luminous efficiency is greatly affected by the chromaticity, so the BI value is introduced as the basis for the efficiency of the blue light emitting material, BI = luminous efficiency / CIEy. In the art, the short service life and low efficiency of the blue light device have been one of the problems that the skilled in the art urgently need to solve, and in the art, a significant improvement has been achieved by increasing the BI value by 7-8%.

[0157] The blue light emitting auxiliary material provided by the present application is based on benzofluorine, and a triarylamine group is connected to naphthalene, and a 9-phenyl-9H-carbazole is connected to the benzene on the other side. As can be seen from Table 2, compared with the existing organic electroluminescent devices provided by Comparative Examples 1-7, the organic electroluminescent devices prepared by using the blue light emitting auxiliary material provided by the present application have the technical effect of improving the device service life and significantly improving the luminous efficiency while maintaining the driving voltage substantially unchanged.

[0158] The compound 20 of the present application and the comparative compound 1; the compound 21 and the comparative compound 2 are different in that the present application is based on benzofluorine, and the comparative compound is dibenzofuran. The benzofluorine retains the advantage of high triplet energy level of dibenzofuran, and on this basis, the conjugated plane is increased, the hole transport rate is increased, and the extension of the conjugated plane is avoided, which improves the device efficiency, and the BI value is increased by about 8%, and the efficiency is increased by 8%.

[0159] The main difference between the compound 6 of the present application and the comparative compound 3 is the substitution position of 9-phenyl-9H-carbazole and triarylamine. The device performance shows that the service life of the comparative compound 3 is comparable to that of compound 6, but the luminous efficiency of the device is significantly improved by 8%. Among similar compounds, the substitution position of carbazole and triarylamine may have different effects on device performance. On this basis, the substitution position of the compound can be adjusted according to the performance needs of the production line, and our company will further study based on this.

[0160] The compound 26 of the present application and the comparative compound 6 use different carbazoles, and the benzofluorine benzene is connected to 9-phenyl-9H-carbazole. On the one hand, the introduced phenyl bridging structure can avoid the difficulty of electron hopping caused by too large energy gap of the compound, so as to make the compound structure stable.

[0161] It can be seen that among similar substances, the position of the ring and the substituent group on the ring will affect the triplet energy level and the mobility, and further affect the device performance in the organic electroluminescence. Although the compound structure of the present application is similar to that of the prior art, only the compound meeting the formula I of the present application can significantly improve the performance advantage of the luminous efficiency as the blue light emitting auxiliary layer.

[0162] The various embodiments described in this specification are presented by way of example, and each embodiment is not necessarily composed of all features described with respect to other embodiments. Each embodiment described in this specification can be implemented in conjunction with one or more other embodiments described in this specification without departing from the scope or spirit of the application. In the drawings, the same reference numbers and designations in different drawings indicate the same elements. The headings (such as "Embodiment," "Exemplary Embodiment," etc.) should not be interpreted as limiting the scope of the application.

[0163] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A luminescent auxiliary material, characterized in that, The general structural formula of the luminescent auxiliary material is shown in Formula I: in, Ar fuses with the adjacent benzene ring; Ar represents phenyl; Ar1 and Ar2 are independently selected from unsubstituted C6-C30 aryl groups and unsubstituted C3-C30 heteroaryl groups.

2. The luminescent auxiliary material according to claim 1, characterized in that, Ar1 and Ar2 are independently selected from unsubstituted C6-C18 aryl groups and unsubstituted C3-C24 heteroaryl groups.

3. The luminescent auxiliary material according to claim 2, characterized in that, The Ar1 and Ar2 are independently selected from phenyl, biphenyl, terphenyl, naphthyl, binatyl, phenylnaphthyl, naphthylphenyl, phenyl terphenyl, fluorenyl, diphenylfluorenyl, benzo[a]fluorenyl, dibenzo[a]fluorenyl, phenanthryl, phenylphenanthryl, anthracene, indene, triphenylene, pyrene, peryl, trefyl, naphthyl, fluoranthyl, spirodifluorenyl, azulel.

4. The luminescent auxiliary material according to claim 2, characterized in that, Ar1 and Ar2 are independently selected from furanyl, thiophene, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetraazinyl, triazolyl, tetraazolyl, furazonyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, benzofuranyl, benzothiophene, isobenzofuranyl, dibenzofuranyl, dibenzothiophene, benzimidazolyl, benzyl benzothiazolyl, benzoisothiazolyl, benzoisoxazolyl, benzoxazolyl, isoindolyl, indolyl, benzoindolyl, indazole, benzothiadiazolyl, quinolinyl, isoquinolinyl, cinolinyl, quinazolinyl, benzoquinazolinyl, quinoxalinyl, benzoquinoxalinyl, naphridinyl, carbazole, benzocarbazole, dibenzocarbazole, phenoxazinyl, phenthiazinyl, phenanthidyl, benzodioxacyclopentenyl or dihydroacridinyl.

5. A luminescent auxiliary material according to claim 3 or 4, characterized in that, Formula I includes the following structure:

6. A luminescent auxiliary material, characterized in that, The luminescent auxiliary material specifically includes the following structure:

7. A method for preparing the luminescent auxiliary material as described in claim 1, characterized in that, The synthesis route is as follows: Hal1 and Hal2 are selected from Cl, Br, and I; R' is... Ar1-Ar2, where Ar has the same range as in Formula I of claim 1; Preparation methods include: (1) Under N2 protection, reactants AI, BI, palladium catalyst and base are added to a mixed solvent of toluene, ethanol and water, respectively, and the temperature is raised to 80-100℃. The reaction is carried out for 8-14 hours to obtain intermediate CI. (2) After adding intermediate CI and reactant DI to the reaction vessel and dissolving them in xylene, palladium catalyst, phosphorus ligand and base are added under nitrogen protection. After addition, the reaction temperature is slowly raised to 120-140℃ and the mixture is stirred for 8-14 hours. The remaining substances are purified by column chromatography to obtain formula I. The equivalent ratio of reactant AI, reactant BI, palladium catalyst, and base is 1:(1-1.4):(0.01-0.1):(2-4); The equivalent ratio of the intermediate CI, reactant DI, palladium catalyst, phosphorus ligand and base is: 1:(1-1.5):(0.01-0.1):(0.01-1):(2-3); or, The synthesis route is as follows: Hal1 and Hal2 are selected from Cl, Br, and I; R' is... Ar1-Ar2, where Ar has the same range as in Formula I of claim 1; Preparation methods include: (1) After reactants AI and BI are dissolved in toluene in a reaction vessel, palladium catalyst, phosphorus ligand and base are added under nitrogen protection. After addition, the reaction temperature is slowly raised to 85-95℃ and the mixture is stirred for 6-14 hours to obtain intermediate CI. (2) Under N2 protection, intermediate CI 1.0 eq, reactant DI 1.0-1.5 eq, palladium catalyst 0.01-0.1 eq, phosphorus ligand 0.01-1.0 eq, and base 2.0-3.0 eq were added to a mixed solvent of toluene, ethanol, and water, respectively. The mixture was heated to 80-90℃ and reacted for 6-12 h to obtain Formula I. The equivalent ratio of reactant AI, reactant BI, palladium catalyst, phosphorus ligand and base is: 1:(1-1.5):(0.01-0.1):(0.01-1):(2-3); The equivalent ratio of the intermediate CI, reactant DI, palladium catalyst, phosphorus ligand and base is 1:(1-1.5)(0.01-0.1):(0.01-1):(2-3).

8. An organic electroluminescent device, characterized in that, It includes a light-emitting auxiliary layer, wherein the light-emitting auxiliary layer comprises the light-emitting auxiliary material as described in claim 1.

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