CN113380964A

CN113380964A - Organic electroluminescent device

Info

Publication number: CN113380964A
Application number: CN202010157285.5A
Authority: CN
Inventors: 吴俊宇; 孙恩涛
Original assignee: Hefei Dingcai Technology Co ltd
Current assignee: Hefei Dingcai Technology Co ltd
Priority date: 2020-03-09
Filing date: 2020-03-09
Publication date: 2021-09-10

Abstract

The invention relates to the field of organic electroluminescence, in particular to an organic electroluminescent device adopting a novel functional material scheme. The organic electroluminescent device comprises an anode, a cathode and one or more organic layers positioned between the anode and the cathode, wherein the organic layers comprise a light-emitting layer and an electron auxiliary layer, the electron auxiliary layer is positioned between the light-emitting layer and the cathode, and the electron auxiliary layer comprises a compound shown as the following formula (1):

the organic electroluminescent device has low starting voltage, high luminous efficiency and better service life, and can meet the requirements of current panel manufacturing enterprises on high-performance materials.

Description

Organic electroluminescent device

Technical Field

The invention relates to the field of organic electroluminescence, in particular to an organic electroluminescent device adopting a novel functional material scheme.

Background

Organic Light Emission Diodes (OLED) devices are a kind of devices with sandwich-like structure, which includes positive and negative electrode films and Organic functional material layers sandwiched between the electrode films. And applying voltage to the electrodes of the OLED device, injecting positive charges from the positive electrode and injecting negative charges from the negative electrode, and transferring the positive charges and the negative charges in the organic layer under the action of an electric field to meet for composite luminescence. Because the OLED device has the advantages of high brightness, fast response, wide viewing angle, simple process, flexibility and the like, the OLED device is concerned in the field of novel display technology and novel illumination technology. At present, the technology is widely applied to display panels of products such as novel lighting lamps, smart phones and tablet computers, and further expands the application field of large-size display products such as televisions, and is a novel display technology with fast development and high technical requirements.

In order to improve the efficiency of the device, the OLED device is usually manufactured by using a dual-host light emitting layer, which increases the light emitting efficiency to a certain extent, but increases the use of an evaporation source, and thus the manufacturing is slightly difficult, which limits the commercial development of OLEDs.

In an OLED device, it is known that hole transport is generally faster than electron transport, and a recombination region in a light emitting layer is biased toward an ET layer direction, which causes adverse effects such as reduction in device efficiency; although the increase of the thickness of the hole transport layer slows down the transport of holes to the cathode, the voltage of the device is improved, and meanwhile, the energy level barriers between different material layers cause a large amount of positive and negative carriers to be respectively accumulated at respective interfaces, so that the efficiency of the device is reduced.

In recent years, people in the industry have continuously tried and explored to improve the efficiency and stability of devices, wherein new materials are sought to improve the performance of devices, and a large number of novel materials are developed to be applied to the transmission of electrons.

Disclosure of Invention

In order to solve the problems in the prior art, the present invention provides an organic electroluminescent device using a novel functional material scheme to improve the performance of the organic electroluminescent device. The introduction of the novel electronic auxiliary layer can obviously improve the carrier transmission efficiency in the device, reduce the energy level potential barrier, and better reduce the problem of carrier accumulation at the interface between material layers, so that the voltage of the device is lower, and the efficiency and the service life are improved to a certain extent.

In order to achieve the purpose, the invention adopts the following technical scheme:

an organic electroluminescent device comprising an anode, a cathode and one or more organic layers disposed between the anode and the cathode, the organic layers comprising a light-emitting layer and an electron assist layer disposed between the light-emitting layer and the cathode, the electron assist layer comprising a compound represented by the following formula (1):

in formula (1): l is selected from substituted or unsubstituted C₆-C₃₀An arylene group of (a);

further, when L is selected from substituted arylene, the substituent is preferably C₃-C₃₀The heteroaryl group of (a);

R¹、R²and R³Each independently selected from hydrogen, cyano, substituted or unsubstituted C₁-C₁₀Alkyl or cycloalkyl, substituted or unsubstituted C₆-C₃₀Aryl, substituted or unsubstituted C₃-C₃₀The heteroaryl group of (a);

ar is an electron-withdrawing group, and is preferably a substituent group represented by the following formula (A):

in the formula (A), X¹-X⁶Each independently selected from nitrogen atom, CH or CR, at least one of which is nitrogen atom, and each R is independently selected from C₁-C₁₀Alkyl radical, C₁-C₁₀Alkoxy, substituted or unsubstituted C₆-C₃₀Aryl, substituted or unsubstituted C₃-C₃₀One of heteroaryl;

when the above groups have substituents, the substituents are respectively and independently selected from halogen and C₁-C₁₀Alkyl or cycloalkyl of, C₂-C₁₀Alkenyl radical, C₁-C₆Alkoxy or thioalkoxy group of (C)₆-C₃₀Monocyclic aromatic hydrocarbon or condensed ring aromatic hydrocarbon group of (A), C₃-C₃₀One of the monocyclic heteroaromatic group or the condensed ring heteroaromatic group of (a).

Further, the general formula (1) is more preferably the following structural formula (1-1), (1-2), (1-3) or (1-4):

in the formulae (1-1), (1-2), (1-3) and (1-4), R¹、R²、R³And L is as defined in the general formula (1);

R⁴selected from hydrogen, cyano, substituted or unsubstituted C₁-C₁₀Alkyl or cycloalkyl, substituted or unsubstituted C₆-C₃₀Aryl, substituted or unsubstituted C₃-C₃₀The substituent groups are respectively and independently selected from halogen and C₁-C₁₀Alkyl or cycloalkyl of, C₂-C₁₀Alkenyl radical, C₁-C₆Alkoxy or thioalkoxy group of (C)₆-C₃₀Monocyclic aromatic hydrocarbon or condensed ring aromatic hydrocarbon group of (A), C₃-C₃₀One of the monocyclic or fused ring heteroaromatic group of (a); m is zero to the maximum allowed integer value.

Further, R mentioned above¹To R⁴Each independently selected from the following substituents: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2, 2-trifluoroethyl, phenyl, naphthyl, anthracenyl, benzanthryl, phenanthryl, benzophenanthryl, pyrenyl, grottoyl, perylenyl, anthrylenyl, tetracenyl, pentacenyl, benzopyrenyl, biphenyl, idophenyl, terphenyl, quaterphenyl, fluorenyl, spirobifluorenyl, dihydrophenanthryl, dihydropyrenyl, tetrahydropyrenyl, cis-or trans-indenofluorenyl, trimeric indenyl, isotridecylindenyl, trimeric spiroindenyl, spirotrimeric indenyl, furanic indenylA phenyl group, a benzofuranyl group, an isobenzofuranyl group, a dibenzofuranyl group, a thienyl group, a benzothienyl group, an isobenzothienyl group, a dibenzothienyl group, a pyrrolyl group, an isoindolyl group, a carbazolyl group, an indenocarbazolyl group, a pyridyl group, a quinolyl group, an isoquinolyl group, an acridinyl group, a phenanthridinyl group, a benzo-5, 6-quinolyl group, a benzo-6, 7-quinolyl group, a benzo-7, 8-quinolyl group, a pyrazolyl group, an indazolyl group, an imidazolyl group, a benzimidazolyl group, a naphthoimidazolyl group, a phenanthroimidazolyl group, a pyridoimidazolyl group, a pyrazinoimidazolyl group, a quinoxalinyl group, an oxazolyl group, an benzoxazolyl group, a naphthoxazolyl group, an anthraoxazolyl group, a phenanthroizolyl group, a 1, 2-thiazolyl group, 1, 3-thiazolyl group, a benzothiazolyl group, a pyridazinyl group, a benzopyrazinyl group, a pyrimidinyl group, a pyrimidyl group, a phenanthridinyl group, a benzothienyl group, a 5-quinolyl group, a pyrrolyl group, a 5-8-quinolyl group, a, Quinoxalinyl, 1, 5-diazahthranyl, 2, 7-diazpyrenyl, 2, 3-diazpyrenyl, 1, 6-diazpyrenyl, 1, 8-diazpyrenyl, 4,5,9, 10-tetraazaperylenyl, pyrazinyl, phenazinyl, phenothiazinyl, naphthyridinyl, azacarbazolyl, benzocarbazinyl, phenanthrolinyl, 1,2, 3-triazolyl, 1,2, 4-triazolyl, benzotriazolyl, 1,2, 3-oxadiazolyl, 1,2, 4-oxadiazolyl, 1,2, 5-oxadiazolyl, 1,2, 3-thiadiazolyl, 1,2, 4-thiadiazolyl, 1,2, 5-thiadiazolyl, 1,3, 4-thiadiazolyl, 1,3, 5-triazinyl, 1,2, 4-triazinyl, 1,2, 3-triazinyl, tetrazolyl, 1,2,4, 5-tetrazinyl, 1,2,3, 4-tetrazinyl, 1,2,3, 5-tetrazinyl, purinyl, pteridinyl, indolizinyl, benzothiadiazolyl, or a combination of two of the foregoing.

Further, the compound represented by the general formula (1) of the present invention may preferably be a compound having the following specific structure: C1-C164, these compounds being representative only:

further preferably, in the organic electroluminescent device of the present invention, the organic layer further comprises an electron transport layer, the electron transport layer is located between the electron auxiliary layer and the cathode, the electron transport layer comprises a compound selected from compounds represented by the above general formula (1), or the electron transport layer comprises any one compound selected from the following formulas ET-1 to ET-52:

further preferably, in the organic electroluminescent device of the present invention, the organic layer further includes an electron transport layer, and the electron transport layer is located between the electron auxiliary layer and the cathode. The electron transport layer comprises a compound selected from the compounds shown in the general formula (1) or the host material is selected from the compounds shown in any one of the formulas ET-1 to ET-52.

Further preferably, in the organic electroluminescent device according to the present invention, the electron transport layer is composed of a host material and a dopant material, the dopant material is Liq, the host material is selected from a compound represented by the above general formula (1), or the host material is selected from a compound represented by any one of the above formulas ET-1 to ET-52.

Further preferably, in the organic electroluminescent device of the present invention, the thickness of the electron auxiliary layer is 1 to 20nm, preferably 5 to 10 nm.

Further preferably, in the organic electroluminescent device of the present invention, the thickness of the electron transport layer is 10 to 50nm, preferably 20 to 30 nm.

Further preferably, in the organic electroluminescent device of the present invention, the host material and the dopant material in the electron transport layer are prepared by a double-source co-evaporation process.

Further preferably, in the organic electroluminescent device of the present invention, a ratio of the host material to the dopant material in the electron transport layer is 1:0.1 to 1:2, and a preferred ratio is 1:1.0 to 1: 1.5.

Further preferably, in the organic electroluminescent device according to the present invention, the organic layer further includes a hole transport layer and/or a hole injection layer between the light-emitting layer and the anode.

The organic electroluminescent device of the invention adopts the compound with the specific structure as shown in the general formula (1) as the electron auxiliary layer in the device, which can promote electrons in the cathode to be injected into the luminescent layer more easily, balance the number of carriers in the device effectively and improve the recombination efficiency of the carriers effectively. In a more preferable scheme of the invention, the electron auxiliary layer and the electron transport layer which is formed by the compound shown in the general formula (1) and the specific doping material are combined and matched for use, so that the performance of the device is optimized, the luminous efficiency of the device can be obviously improved, and the energy level barrier of the device can be reduced, thereby reducing the voltage of the organic electroluminescent device.

Drawings

Fig. 1 is a schematic structural diagram of an organic electroluminescent device according to an embodiment of the present invention;

in FIG. 1,1 is an anode; 2 is a hole transport layer; 3 is a light emitting layer; 4 an electron assist layer; 5 is an electron transport layer; and 6 is a cathode.

Detailed Description

The invention is described in detail below with reference to the figures and the specific embodiments. The present invention is not limited to the following embodiments, but is merely illustrative of the present invention.

The organic electroluminescent device is prepared by a vacuum evaporation method, can also be prepared by other methods, and is not limited to vacuum deposition. The invention is illustrated only with devices prepared by vacuum deposition. Cleaning a substrate, baking, pretreating, putting the substrate into a cavity, and sequentially carrying out vacuum deposition on a hole injection layer, a hole transport layer, a luminescent layer, an electron auxiliary layer, an electron transport layer and a cathode.

The substrate may be a rigid substrate including a glass substrate, a Si substrate, or the like, or a flexible substrate including a polyvinyl alcohol (PVA) film, a Polyimide (PD) film, a Polyester (PET) film, or the like. The substrate of the present invention is preferably a rigid glass substrate.

The anode may preferably be a conductive compound, alloy, metal or mixture of such materials having a large work function. Inorganic materials may be used, and the inorganic materials include metal oxides such as Indium Tin Oxide (ITO), zinc oxide (ZnO), Indium Zinc Oxide (IZO), and tin oxide (SnO), and laminates of metals having a high work function such as gold, silver, copper, and aluminum, or alternately formed of metals and metals or non-metals. ITO is preferred as the anode of the present invention.

The hole transport region includes a hole transport layer and/or a hole injection layer, and the specific material may be selected from, but is not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylenevinylene, 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 below in HT-1 to HT-34, or any combination thereof.

In one aspect of the invention, the light-emitting layer employs a fluorescent electroluminescence technique. The luminescent layer fluorescent host material may be selected from, but not limited to, a combination of one or more of BFH-1 through BFH-17 listed below.

The fluorescent dopant of the luminescent layer is one of BFD-1 to BFD-12:

in one aspect of the invention, the light-emitting layer employs phosphorescent electroluminescent technology. The host material of the light emitting layer is selected from, but not limited to, one or more of GPH-1 to GPH-80.

In one aspect of the invention, the light-emitting layer employs phosphorescent electroluminescent technology. The phosphorescent dopant of the light emitting layer can be selected from, but is not limited to, one or more of GPD-1 to GPD-47 listed below.

In one aspect of the invention, the light-emitting layer employs phosphorescent electroluminescent technology. The host material of the light emitting layer is selected from, but not limited to, one or more of RH-1 to RH-31.

In one aspect of the invention, the light-emitting layer employs phosphorescent electroluminescent technology. The phosphorescent dopant of the light emitting layer thereof may be selected from, but not limited to, a combination of one or more of RPD-1 to RPD-28 listed below.

In one aspect of the invention, the light-emitting layer employs phosphorescent electroluminescent technology. The phosphorescent dopant of the light-emitting layer can be selected from, but is not limited to, one or more of YPD-1-YPD-11 listed below.

In one aspect of the invention, the light-emitting layer employs a thermally activated delayed fluorescence emission technique. The fluorescent dopant of the light-emitting layer can be selected from, but is not limited to, one or more of TDE1-TDE39 listed below.

In one aspect of the invention, the light-emitting layer employs a thermally activated delayed fluorescence emission technique. The host material of the light emitting layer is selected from, but not limited to, one or more of TDH-1-TDH-24.

In the organic electroluminescent device of the present invention, the electron auxiliary layer is made of the material of the general formula (1), wherein the synthesis preparation method of the partial representative compound of the general formula (1) is as follows:

synthesis of compound C4:

the synthetic route is as follows:

preparation of Compound 1-1

2-amino-5-bromopyrazine (17.3g, 100mmol), phenanthreneboronic acid (22.2g, 1000mmol), potassium carbonate (41.4g, 300mmol), [1,1' -bis (diphenylphosphino) ferrocene ] dichloropalladium (0.73g, 1mmol) were added to a single vial, and the solvent tetrahydrofuran 300mL and water 60mL were added, and the reaction was refluxed at 80 ℃ under nitrogen protection overnight. Solid is separated out in the reaction process. And (3) detecting the reaction completion of the raw materials by TLC, stopping the reaction, cooling to room temperature, filtering the precipitated solid, respectively leaching with water and ethanol, and drying. The objective compound 1-1(24.4g, yield 90%) was obtained.

Preparation of Compounds 1-2

Intermediate compound 1-1(22.6g, 83.33mmol) was added to a flask containing DCM (100mL), cooled to 0 deg.C, ethoxycarbonyl isothiocyanate (10.92g, 83.33mmol) was slowly added dropwise, the reaction was warmed to room temperature, and stirred for 20 h. The solvent was appropriately removed by distillation under the reduced pressure, and filtration was performed. After drying with warm air, the desired product 1-2(31.2g, yield 93%) was obtained.

Preparation of Compounds 1-3

Hydroxylamine hydrochloride (23.29g, 337.58mmol) was added to ethanol (200ml), triethylamine (22.73g, 225.06mmol) was added to the reaction solution, and stirring was carried out for 1 h. 1-2(30.2g, 75.02mmol) synthesized above was added, the temperature was slowly raised, and the mixture was refluxed for 3 hours. The temperature was cooled to room temperature and the resulting solid was filtered. Mixing the obtained solid products, washing with distilled water, ethanol and n-hexane, and drying with warm air to obtain target compound 1-3(21g, yield 90%)

Preparation of Compounds 1-4

To compound 1-3(12.6g, 40.51mmol) synthesized above, copper bromide (2.71g, 12.15mmol) and tetrahydrofuran (100ml) were added. The reaction solution was cooled to 0 ℃ and hydrobromic acid (80ml) was slowly dropped, and sodium nitrite (8.39g, 121.53mmol) was dissolved in distilled water (30ml) and slowly dropped. The reaction solution was stirred at room temperature for 12 hours. Adding sodium hydroxide aqueous solution (50ml) into the reaction solution, stirring for 1h, extracting the mixture with ethyl acetate, washing with water, drying the organic phase, distilling under reduced pressure, and purifying by silica gel column chromatography to obtain the target product 1-4(9.85g, yield 65%)

Preparation of Compound C4

Adding the compounds 1-4(9.1g, 24.31mmol) and 2- (4-borate group) phenyl-4, 6-diphenyl-1, 3, 5-triazine (10.57g, 24.31mmol) into a three-neck flask, dissolving potassium carbonate (10.06g, 72.93mmol) in 30mL of water, adding into the three-neck flask, adding 150mL of tetrahydrofuran, adding [1,1' -bis (diphenylphosphino) ferrocene ] palladium dichloride (0.53g, 0.73mmol) to replace nitrogen for 3 times, heating the oil bath to 80 ℃ for reaction for 4-5 hours, and monitoring the reaction by TLC. Cooling the reaction solution to room temperature, extracting with ethyl acetate, combining organic phases, drying and concentrating; dissolving DCM, performing column chromatography, collecting a product, concentrating, boiling and dissolving the product in toluene at 120 ℃, slowly adding ethanol with the same volume as the toluene, continuously stirring for 0.5h, stopping heating, naturally cooling to room temperature, fully separating out the product, filtering, and drying to obtain a white solid compound C4(10.4g, yield 71%). Calculated molecular weight: 603.22, found C/Z: 603.2.

Synthesis of compound C35:

the synthetic route is as follows:

synthesized by a synthesis method similar to that of C4. The difference is that in the first step, 2-amino-3, 5-dibromopyrazine is used to replace 2-amino-5-bromopyrazine, and phenylboronic acid is used to replace 9-phenanthrene boric acid Suzuki reaction to synthesize the intermediate 3-1. A white solid compound C35 was obtained by a similar synthetic method, calculated as molecular weight: 579.22, found C/Z: 579.2.

Synthesis of compound C51:

the synthetic route is as follows:

synthesis of intermediate 6-2

Compound 6-1(38.7g,0.1mol), 3-chlorobenzeneboronic acid (17.2g,0.11mol) and potassium carbonate (41.4g,0.3mol) were dissolved in a flask containing toluene/ethanol/water (300mL/50mL/50mL), and Pd (PPh3)4(1.15g,0.001mol) was added thereto after replacing nitrogen with stirring at room temperature. After the addition was complete, the reaction was refluxed with stirring for 4 hours, and the end of the reaction was monitored by TLC. Cooling to room temperature, filtering, washing the solid with toluene, water and ethanol, and air drying. Purification by column chromatography gave compound 6-2(38.1g, 91% yield).

Preparation of Compound 6-3

Compound 6-2(33.5g,0.08mol), pinacol borate (30.5g,0.12mol) and potassium acetate (24g,0.24mol) were charged into a flask containing 1, 4-dioxane (300mL), and after replacing nitrogen with stirring at room temperature, Pd2(dba)3(733mg,0.8mmol) and sphos (1g,1.6mmol) were added. . After the addition was complete, the reaction was refluxed with stirring for 24 hours, and the end of the reaction was monitored by TLC. The precipitated solid was filtered. Water washing and drying gave compound 6-3(32.7g, yield 80%).

Synthesis of Compound C51

Synthesized by a synthesis method similar to that of C35. Except that in the fifth step, the intermediate 6-3 is used for replacing 2- (4-borate group) phenyl-4, 6-diphenyl-1, 3, 5-triazine, and a white solid compound C51 is obtained by a similar synthesis method, and the calculated molecular weight is as follows: 655.25, found C/Z: 655.3.

Synthesis of compound C94:

the synthetic route is as follows:

synthesis of intermediate 8-1

The compound 2-chloro-4-phenylquinazoline (24g,0.1mol), 4-chlorobenzeneboronic acid (17.2g,0.11mol) and potassium carbonate (41.4g,0.3mol) were dissolved in a flask containing toluene/ethanol/water (300mL/50mL/50mL), and Pd (PPh3)4(1.15g,0.001mol) was added after replacing nitrogen with stirring at room temperature. After the addition was complete, the reaction was refluxed with stirring for 4 hours, and the end of the reaction was monitored by TLC. Cooling to room temperature, filtering, washing the solid with toluene, water and ethanol, and air drying. Purification by column chromatography gave compound 8-1(29g, 92% yield).

Preparation of Compound 8-2

Compound 8-1(25.3g,0.08mol), pinacol borate (30.5g,0.12mol) and potassium acetate (24g,0.24mol) were charged into a flask containing 1, 4-dioxane (300mL), and after replacing nitrogen with stirring at room temperature, Pd2(dba)3(733mg,0.8mmol) and sphos (1g,1.6mmol) were added. After the addition was complete, the reaction was refluxed with stirring for 24 hours, and the end of the reaction was monitored by TLC. The precipitated solid was filtered. Water washing and drying gave compound 8-2(26.4g, yield 81%).

Synthesis of Compound C94

Synthesized by a synthesis method similar to that of C4. Except that in the fifth step, the intermediate 8-2 is used for replacing 2- (4-borate group) phenyl-4, 6-diphenyl-1, 3, 5-triazine, and a white solid compound C94 is obtained by a similar synthesis method, and the calculated molecular weight is as follows: 576.21, found C/Z: 576.2.

The preparation process of the organic electroluminescent device in the embodiment of the invention is as follows:

comparative examples 1 to 1

The glass plate coated with the ITO transparent conductive layer was sonicated in a commercial detergent, rinsed in deionized water, washed in acetone: ultrasonically removing oil in an ethanol mixed solvent, baking in a clean environment until the water is completely removed, cleaning by using ultraviolet light and ozone, and bombarding the surface by using low-energy cationic beams;

placing the glass substrate with the anode in a vacuum chamber, and vacuumizing to 1 × 10^-5～9×10^-3Pa, vacuum evaporating HT1 on the anode layer film to form a hole transport layer of the device, wherein the evaporation rate is 0.1nm/s, and the total evaporation film thickness is 80 nm;

and (3) evaporating a light emitting layer of the device on the hole transport layer in vacuum, wherein the light emitting layer comprises a main material BFH-1 and a dye BFD-1, the main material rate is 0.1nm/s, the dye rate is 0.005nm/s, and the total film thickness of evaporation is 20nm by using a multi-source co-evaporation method.

Vacuum evaporation is carried out on the electron transport layer material ET-1: Liq on the luminescent layer, the evaporation rates of ET-1 and Liq are both 0.1nm/s, and the total film thickness of evaporation is 23 nm;

an Mg/Ag layer with the thickness of 150nm is vacuum evaporated on the Electron Transport Layer (ETL) to be used as a cathode of the device.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/ET-1: 100% Liq (23)/Mg: Ag (150)

Comparative examples 1 to 2

a luminescent layer of the device is evaporated on the hole transport layer in vacuum, the luminescent layer comprises a main material BFH-1 and a dye BFD-1, the speed of the main material is 0.1nm/s, the speed of the dye is 0.005nm/s, and the total film thickness of evaporation is 20nm by using a multi-source co-evaporation method;

and vacuum evaporating a hole barrier layer material ET-2 of the device on the light emitting layer, wherein the evaporation rate is 0.1nm/s, and the evaporation film thickness is 5 nm.

Carrying out vacuum evaporation on the electron transport layer material ET-1 of the device on the hole blocking layer by 100% Liq, wherein the evaporation rate of ET-1 is 0.1nm/s, and the total film thickness of evaporation is 23 nm;

The device structure is as follows:

ITO/HT-1(80)/BFH-1:5％BFD-1(20)/ET-2(5)/ET-1:100％Liq(23)/Mg:Ag(150)

examples 1 to 1

The electron assist layer material C4 of the device was vacuum-deposited on the light-emitting layer at a deposition rate of 0.1nm/s and a deposition thickness of 1 nm.

Carrying out vacuum evaporation on the electron auxiliary layer to obtain an electron transport layer material ET-1: 100% Liq, wherein the evaporation rate of ET-1 is 0.1nm/s, and the total film thickness of evaporation is 23 nm;

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(1)/ET-1: 100% Liq (23)/Mg: Ag (150)

Examples 1 to 2

The electron assist layer material C4 of the device was vacuum-deposited on the light-emitting layer at a deposition rate of 0.1nm/s and a deposition thickness of 3 nm.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(3)/ET-1: 100% Liq (23)/Mg: Ag (150)

Examples 1 to 3

The electron assist layer material C4 of the device was vacuum-deposited on the light-emitting layer at a deposition rate of 0.1nm/s and a deposition thickness of 5 nm.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/ET-1: 100% Liq (23)/Mg: Ag (150)

Examples 1 to 4

In accordance with the preparation process of examples 1-2, except that the electron assist layer was 7nm thick.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(7)/ET-1: 100% Liq (23)/Mg: Ag (150)

Examples 1 to 5

In accordance with the preparation process of examples 1-2, except that the thickness of the electron assist layer was 10 nm.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(10)/ET-1: 100% Liq (23)/Mg: Ag (150)

Examples 1 to 6

In accordance with the preparation process of examples 1-2, except that the thickness of the electron-assist layer was 15 nm.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(15)/ET-1: 100% Liq (23)/Mg: Ag (150)

Examples 1 to 7

In accordance with the preparation process of examples 1-2, except that the thickness of the electron assist layer was 20 nm.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(20)/ET-1: 100% Liq (23)/Mg: Ag (150)

Examples 1 to 8

Consistent with the preparation method of examples 1-3, except that the electron assist layer material was C51.

The device structure is as follows:

ITO/HT-1(80)/BFH-1:5％BFD-1(20)/C51(5)/ET-1:100％Liq(23)/Mg:Ag(150)

examples 1 to 9

Consistent with the preparation method of examples 1-3, except that the electron assist layer material was C94.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C94(5)/ET-1: 100% Liq (23)/Mg: Ag (150)

The device testing method comprises the following steps: the organic electroluminescent device prepared by the above process was subjected to the following performance measurement:

the driving voltage and current efficiency of the organic electroluminescent devices prepared in examples and comparative examples were measured at the same luminance using a model ST-86LA luminance meter (photoelectric instrument factory, university of beijing, university) of a PR 750 type photoradiometer by Photo Research, and a Keithley4200 test system. Specifically, the voltage was raised at a rate of 0.1V per second, and the voltage when the luminance of the organic electroluminescent device reached 1000cd/m2, that is, the driving voltage, was measured, and the current density at that time was also measured; the ratio of the brightness to the current density is the current efficiency; the life test of LT95 is as follows: the time in hours for which the luminance of the organic electroluminescent device dropped to 2850cd/m2 was measured using a luminance meter at a luminance of 3000cd/m2 while maintaining a constant current.

Tests were conducted on the devices prepared in examples 1-1 to 1-7 and comparative examples 1-1 and 1-2 above, and the results of the properties of the respective materials in the light-emitting layer and the prepared devices are shown in table 1 below:

table 1:

as can be seen from the content in table 1 above, when the compound represented by the general formula (1) of the present invention is used for an electronic auxiliary layer of a device, the overall performance of the prepared device is significantly improved, especially the efficiency of the device is significantly improved, compared with the performance of a device prepared by a comparative example using a material scheme of a device in the prior art, and the performance of the device is optimal when the thickness of the electronic auxiliary layer is 5-10 nm.

Example 2-1

a luminescent layer of the device is vacuum evaporated on the hole transport layer, the luminescent layer comprises a main material BFH-1 and a dye BFD-1, the speed of the main material is 0.1nm/s, the speed of the dye is 0.005nm/s, and the total film thickness of the evaporated layer is 20nm by utilizing a multi-source co-evaporation method

The electron transport layer of the device is vacuum evaporated on the electron auxiliary layer, the adopted materials are C51 used as a main material and Liq used as a doping material, the evaporation rates of C51 and Liq are both 0.1nm/s, and the total evaporation film thickness is 10 nm;

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C51: 100% Liq (10)/Mg: Ag (150)

Examples 2 to 2

This example was prepared in exactly the same manner as example 2-1, except that the ETL layer was 15nm thick.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C51: 100% Liq (15)/Mg: Ag (150)

Examples 2 to 3

This example was prepared in exactly the same manner as example 2-1, except that the ETL layer was 23nm thick.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C51: 100% Liq (23)/Mg: Ag (150)

Examples 2 to 4

This example was prepared in exactly the same manner as example 2-1, except that the ETL layer was 25nm thick.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C51: 100% Liq (25)/Mg: Ag (150)

Examples 2 to 5

This example was prepared in exactly the same manner as example 2-1, except that the ETL layer was 30nm thick.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C51: 100% Liq (30)/Mg: Ag (150)

Examples 2 to 6

This example was prepared in exactly the same manner as example 2-1, except that the ETL layer was 40nm thick.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C51: 100% Liq (40)/Mg: Ag (150)

Examples 2 to 7

This example was prepared in exactly the same manner as example 2-1, except that the ETL layer was 50nm thick.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C51: 100% Liq (50)/Mg: Ag (150)

Examples 2 to 8

This example was prepared in exactly the same manner as examples 2 to 3, except that the evaporation rate ratio C51: Liq in the ETL layer was 1: 0.1.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C51: 10% Liq (23)/Mg: Ag (150)

Examples 2 to 9

This example was prepared in exactly the same manner as examples 2 to 3, except that the evaporation rate ratio C51: Liq in the ETL layer was 1: 0.5.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C51: 50% Liq (23)/Mg: Ag (150)

Examples 2 to 10

This example was prepared in exactly the same manner as examples 2-3, except that the evaporation rate ratio C51: Liq in the ETL layer was 1: 1.2.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C51: 120% Liq (23)/Mg: Ag (150)

Examples 2 to 11

This example was prepared in exactly the same manner as examples 2-3, except that the evaporation rate ratio C51: Liq in the ETL layer was 1: 1.5.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C51: 150% Liq (23)/Mg: Ag (150)

Examples 2 to 12

This example was prepared in exactly the same manner as examples 2-3, except that the evaporation rate ratio C51: Liq in the ETL layer was 1: 2.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C51: 200% Liq (23)/Mg: Ag (150)

Examples 2 to 13

This example was prepared in exactly the same manner as examples 2 to 8, except that the electron assist layer was 1nm thick.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(1)/C51: 120% Liq (23)/Mg: Ag (150)

Examples 2 to 14

This example was prepared in exactly the same manner as examples 2-8, except that the electron assist layer was 3nm thick.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(3)/C51: 120% Liq (23)/Mg: Ag (150)

Examples 2 to 15

This example was prepared in exactly the same manner as examples 2 to 8, except that the electron assist layer was 7nm thick.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(7)/C51: 120% Liq (23)/Mg: Ag (150)

Examples 2 to 16

This example was prepared in exactly the same manner as examples 2 to 8, except that the electron assist layer was 10nm thick.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(10)/C51: 120% Liq (23)/Mg: Ag (150)

Examples 2 to 17

This example was prepared in exactly the same manner as examples 2 to 8, except that the electron assist layer was 15nm thick.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(15)/C51: 120% Liq (23)/Mg: Ag (150)

Examples 2 to 18

This example was prepared in exactly the same manner as examples 2 to 8, except that the electron assist layer was 20nm thick.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(20)/C51: 120% Liq (23)/Mg: Ag (150)

Examples 2 to 19

This example was prepared in exactly the same manner as examples 2-3, except that C4 was replaced with C51 in the electron assist layer.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C51(5)/C51: 100% Liq (23)/Mg: Ag (150)

Examples 2 to 20

This example was prepared in exactly the same manner as examples 2-3, except that C51 was replaced with C4 in the ETL.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C4: 100% Liq (23)/Mg: Ag (150)

Examples 2 to 21

This example was prepared in exactly the same manner as examples 2-3, except that C51 was replaced with C94 in the ETL layer.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C94: 100% Liq (23)/Mg: Ag (150)

Examples 2 to 22

This example was prepared in exactly the same manner as examples 2-13, except that C4 in the electron assist layer was replaced with C51.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C51(5)/C94: 100% Liq (23)/Mg: Ag (150)

Examples 2 to 23

This example was prepared in exactly the same manner as examples 2-3, except that only C51 was used in the ETL.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/C51(23)/Mg: Ag (150)

Examples 2 to 24

This example was prepared in full agreement with examples 2-3, except that only Alq3 was used in the ETL.

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/C4(5)/Alq3(23)/Mg: Ag (150)

Comparative example 2-1

a luminescent layer of the device is vacuum evaporated on the hole transport layer, the luminescent layer comprises a main material BFH-1 and a dye BFD-1, the speed of the main material is 0.1nm/s, the speed of the dye is 0.05nm/s, and the total film thickness of the evaporated layer is 20nm by utilizing a multi-source co-evaporation method

And vacuum evaporating a hole barrier layer material ET-2 of the device on the light emitting layer, wherein the evaporation rate is 0.1nm/s, and the evaporation film thickness is 6 nm.

The electron transport layer material Alq3 of the device is evaporated in the positive air above the hole blocking layer, the evaporation rate is 0.1nm/s, and the total film thickness of the evaporation is 23 nm;

The device structure is as follows: ITO/HT-1(80)/BFH-1: 5% BFD-1(20)/ET-2(5)/Alq3(23)/Mg: Ag (150)

The above examples and comparative devices were tested, and the results of the properties of the materials in the light emitting layer and the devices prepared are shown in table 2 below.

Table 2:

as can be seen from the content in table 2 above, when the compound represented by the general formula (1) of the present invention is used for an electronic auxiliary layer of a device, and the general formula is matched with an electron transport layer formed by doping the compound represented by the general formula (1) of the present invention and Liq, the overall performance of the prepared device is significantly improved compared with the performance of a device prepared by a comparative example adopting a material scheme of a device in the prior art, and when the thickness of the electronic auxiliary layer is 5-10nm, the ETL thickness is 20-30 nm, and the doping ratio is 1: 1-1: 1.5, the device performance is optimal.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention.

Claims

1. An organic electroluminescent device comprising an anode, a cathode and one or more organic layers disposed between the anode and the cathode, wherein the organic layers comprise a light-emitting layer and an electron assist layer disposed between the light-emitting layer and the cathode, and the electron assist layer comprises a compound represented by the following formula (1):

2. The organic electroluminescent device according to claim 1, wherein the compound represented by the general formula (1) is represented by the following structural formula (1-1), (1-2), (1-3) or (1-4):

R⁴selected from hydrogen, cyano, substituted or unsubstituted C₁-C₁₀Alkyl or cycloalkyl, substituted or unsubstituted C₆-C₃₀Aryl, substituted or unsubstitutedC₃-C₃₀The substituent groups are respectively and independently selected from halogen and C₁-C₁₀Alkyl or cycloalkyl of, C₂-C₁₀Alkenyl radical, C₁-C₆Alkoxy or thioalkoxy group of (C)₆-C₃₀Monocyclic aromatic hydrocarbon or condensed ring aromatic hydrocarbon group of (A), C₃-C₃₀One of the monocyclic or fused ring heteroaromatic group of (a); m is zero to the maximum allowed integer value.

3. The organic electroluminescent device according to claim 1, wherein the compound of formula (1) is selected from any one of the following compounds C1-C164:

4. the organic electroluminescent device of claim 1, further comprising an electron transport layer in the organic layer, the electron transport layer being located between the electron assist layer and the cathode.

5. The organic electroluminescent device according to claim 4, wherein the electron transport layer comprises a compound selected from the group consisting of compounds as set forth in claims 1 to 3.

6. The organic electroluminescent device according to claim 4, wherein the electron transport layer is composed of a host material and a dopant material, the dopant material is Liq, and the host material is selected from the compounds according to any one of claims 1 to 3.

7. The organic electroluminescent device according to claim 6, wherein the ratio of the host material to the dopant material in the electron transport layer is 1:0.1 to 1:2, preferably 1:1.0 to 1: 1.5.

8. The organic electroluminescent device according to any of claims 1 to 7, characterized in that the thickness of the electron assist layer is 1 to 20nm, preferably 5 to 10 nm.

9. The organic electroluminescent device according to any one of claims 4 to 7, wherein the thickness of the electron transport layer is 10 to 50nm, preferably 20 to 30 nm.

10. The organic electroluminescent device according to any one of claims 1 to 9, wherein the organic layer further comprises a hole transport layer and/or a hole injection layer between the light-emitting layer and the anode.