Organic compounds and organic electroluminescence devices, display devices comprising the same

Abstract

The present application relates to an organic compound and an organic electroluminescence device and a display device comprising the same. The organic compound has the structural characteristics shown in the following formula (I). The organic compound, by means of suitable structural design, uses pyridyl substituted by azaheteroaryl (R3, R4) to coordinate with phenanthryl, can be used as an electron transport material or n-type doped organic material in an organic electroluminescence device, and effectively improves the efficiency and lifetime of the device.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescence technology, and in particular to an organic compound and organic electroluminescent devices and display devices containing the same. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are devices fabricated by depositing one or more layers of organic material between two metal electrodes through spin coating or vacuum evaporation. As early as 1963, Pope et al. published an article on the electroluminescence of anthracene single crystals; however, due to the need for very high driving voltages (>300V), research on anthracene single crystals remained at the basic research level and could not be used in commercial electronic devices. In 1987, Tang and Van Slyke of Kodak developed a sandwich-structured organic light-emitting diode, using aluminum 8-hydroxyquinoline (Alq3) as the electron transport layer and light-emitting layer, and an aromatic diamine as the hole transport layer. The device operated at a voltage less than 10V and achieved a brightness exceeding 1000 cdm². -2 This groundbreaking research sparked a milestone in the development of OLEDs.

[0003] Currently, OLEDs possess advantages such as simple structure, fast response speed, energy saving, wide color gamut, and high contrast, and are widely used in display devices such as mobile phones and computers. A classic OLED's light-emitting unit includes a hole transport layer, an emissive layer, and an electron transport layer. Holes generated by the anode are transported to the emissive layer via the hole transport layer, while electrons generated by the cathode are transported to the emissive layer via the electron transport layer. The two electrons combine in the emissive layer to form excitons, which then emit light. The emission of various light types can be adjusted by changing the material of the emissive layer. Alternatively, two or more light-emitting units can be placed between two electrodes; such OLEDs are called tandem OLEDs. In tandem OLEDs, a charge generation layer (CGL) is located between each pair of emissive layers, specifically comprising an n-type doped organic layer, an interface layer, and a p-type doped organic layer. Its structure differs significantly from classic OLEDs, and compared to classic OLEDs, tandem OLEDs can reduce the current density at the same brightness, improving device efficiency and extending device lifespan.

[0004] However, both classic OLEDs and tandem OLEDs require further improvement in device efficiency and lifespan. Summary of the Invention

[0005] Based on this, the present invention provides an organic compound that can improve device efficiency and lifetime. These compounds can be used as electron transport materials and n-type doped organic materials in organic electroluminescent devices. The present invention also provides a high-efficiency and long-life organic electroluminescent device and display device containing the compounds of the present invention.

[0006] The first aspect of the present invention provides an organic compound having the structural features shown in formula (I):

[0007]

[0008] in,

[0009] R1 and R2 are each independently a substituted or unsubstituted C6-C30 aryl, a substituted or unsubstituted C3-C30 heteroaryl, a substituted or unsubstituted C1-C16 alkyl, a substituted or unsubstituted C1-C16 alkoxy, or a substituted or unsubstituted C3-C16 cycloalkyl.

[0010] L is one of a single bond, a substituted or unsubstituted C6-C30 arylene, or a substituted or unsubstituted C3-C30 heteroarylene;

[0011] Z is N;

[0012] R3 and R4 are each independently a substituted or unsubstituted C3-C30 azaaryl group;

[0013] The substituents include one or more of C1-C25 alkyl, C1-C15 alkoxy, C6-C16 aryl, deuterium, F, and CN.

[0014] In one embodiment, at least one of the groups R1 and R2 contains an N atom;

[0015] Optionally, at least one of R1 and R2 is a C3-C30 azeotropic or a CN-substituted C6-C30 aryl group;

[0016] Further optionally, at least one of R1 and R2 is a C3-C18 azeotropic or a CN-substituted C6-C18 aryl group;

[0017] Alternatively, at least one of R1 and R2 is a C3-C8 azeotropic or a CN-substituted C6-C8 aryl group;

[0018] Alternatively, at least one of R1 and R2 is a phenyl group substituted with pyridyl, quinolinyl, or CN.

[0019] Further optionally, one of R1 and R2 is a C3-C30 azeotropic or CN-substituted C6-C30 aryl, and the other is a C6-C30 aryl;

[0020] Further optionally, in the CN-substituted C6-C30 aryl groups, the substitution site of CN on the C6-C30 aryl group is the first site, and the substitution site of the phenanthrene group on the C6-C30 aryl group is the second site, and the positional relationship between the first site and the second site is ortho, para, or meta.

[0021] Alternatively, the positional relationship between the first site and the second site may be interposition.

[0022] In one embodiment, L is a substituted or unsubstituted C6-C30 arylene, and the substitution site of the phenanthrene group on L is a third site. The substitution site of the group on L is the fourth site, and the positional relationship between the third site and the fourth site is ortho, para, or meta.

[0023] Optionally, the positional relationship between the third site and the fourth site is interposition.

[0024] In one embodiment, L is a single bond or a phenylene oxide.

[0025] In one embodiment, R3 and R4 are each independently a substituted or unsubstituted C3-C15 azeotropic group;

[0026] Optionally, R3 and R4 are each independently C3-C8 azeotropic groups;

[0027] Alternatively, R3 and R4 can be independently pyridyl, quinolinyl, or isoquinolinyl.

[0028] In one embodiment, the azaaryl groups in R3 and R4 contain one nitrogen atom, and the nitrogen atom is located at the fifth position in the azaaryl group. The substitution site of the group on the aziridine group is the sixth site, and the positional relationship between the fifth site and the sixth site is ortho, para, or meta.

[0029] Optionally, the fifth site and the sixth site are adjacent.

[0030] In one embodiment, the organic compound has one of the structural features shown in formulas (I-1) to (I-5):

[0031]

[0032] A second aspect of the invention provides the use of the organic compounds described in the first aspect as electron transport materials and / or n-type doped organic materials.

[0033] A third aspect of the present invention provides the application of the organic compounds described in the first aspect in organic electroluminescent devices, organic solar cells, organic thin-film transistors, organic photodetectors, organic field-effect transistors, organic integrated circuits, or organic photosensors.

[0034] A fourth aspect of the present invention provides an organic electroluminescent device, comprising a first electrode, a second electrode, and a light-emitting unit disposed between the first electrode and the second electrode, wherein the light-emitting unit includes an electron transport layer, and the electron transport layer comprises at least one of the organic compounds described in the first aspect.

[0035] In one embodiment, the electron transport layer further comprises a dopant;

[0036] Optionally, the dopant is a metal complex; the dopant is lithium 8-hydroxyquinoline.

[0037] Optionally, the dopant in the electron transport layer has a mass percentage of 20% to 70%; more preferably, the dopant in the electron transport layer has a mass percentage of 30% to 60%.

[0038] A fifth aspect of the present invention provides a series organic electroluminescent device, comprising a first electrode, a second electrode, and two or more light-emitting units disposed between the first electrode and the second electrode, wherein a charge generation layer is provided between each pair of light-emitting units;

[0039] The light-emitting unit includes an electron transport layer, and the charge-generating layer includes an n-type doped organic layer.

[0040] The electron transport layer and / or the n-type doped organic layer comprise at least one of the organic compounds described in the first aspect.

[0041] In one embodiment, the n-type doped organic layer further comprises a dopant;

[0042] Optionally, the dopant is a metal dopant; further optionally, the dopant is one or more of alkali metals, alkaline earth metals, and rare earth metals; even further optionally, the dopant is one or more of Li, Na, Cs, Mg, Ca, Sr, and Yb.

[0043] Optionally, the dopant in the n-type doped organic layer has a mass percentage of 0.5% to 50%; more preferably, the dopant in the n-type doped organic layer has a mass percentage of 1% to 20%.

[0044] A sixth aspect of the present invention provides a display device comprising at least one of the organic electroluminescent device described in the fourth aspect and the tandem organic electroluminescent device described in the fifth aspect.

[0045] The aforementioned organic compounds, through appropriate structural design, employ pyridinium groups substituted with nitrogen-containing aryl groups (R3, R4) in combination with phenanthrene groups. The pyridinium groups possess high electron mobility, and when used as electron transport materials and n-type dopant materials, they can effectively reduce the operating voltage of organic electroluminescent devices and improve device efficiency. The addition of phenanthrene groups enhances the stability of the organic compounds, effectively extending the device's lifespan. In some embodiments, compared to conventional devices, efficiency can be improved by approximately 10%, and lifespan can be extended by about 15%. Attached Figure Description

[0046] Figure 1 A schematic diagram of the structure of an example organic electroluminescent device is provided.

[0047] Figure 2 A schematic diagram of an organic electroluminescent device provided as another example;

[0048] Figure 3 This is a schematic diagram of a tandem organic electroluminescent device as an example. Detailed Implementation

[0049] The organic compounds of the present invention and organic electroluminescent devices and display devices comprising the present invention will be further described in detail below with reference to specific embodiments. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0051] In this article, "one or more" refers to any one, two or more of the listed items.

[0052] In this invention, terms such as "first aspect," "second aspect," "third aspect," and "fourth aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, terms such as "first," "second," "third," and "fourth" serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0053] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0054] In this invention, numerical ranges are involved. Unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe features or characteristics, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0055] Unless otherwise specified, the percentage content involved in this invention refers to mass percentage for solid-liquid mixtures and solid-phase-solid mixtures, and volume percentage for liquid-phase-liquid mixtures.

[0056] Unless otherwise specified, all percentage concentrations mentioned in this invention refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0057] Unless otherwise specified, the temperature parameters in this invention can be either constant temperature processing or processing within a certain temperature range. The constant temperature processing allows temperature fluctuations within the precision range controlled by the instrument.

[0058] In this invention, room temperature generally refers to 4℃~30℃, and preferably 20±5℃.

[0059] In this invention, "aryl" refers to an aromatic hydrocarbon group derived from an aromatic ring compound by removing one hydrogen atom. It can be a monocyclic aryl, a fused-ring aryl, or a polycyclic aryl. For polycyclic compounds, at least one must be an aromatic ring system. For example, "C6-C30 aryl" refers to an aryl group containing 6 to 30 carbon atoms. Each occurrence can be independently C5, C6, C7, C8, C9, C10, C12, C14, C18, C20, C25, or C30 aryl. Suitable examples include, but are not limited to, benzene, biphenyl, naphthalene, anthracene, phenanthrene, dinaphthalene, triphenylene, and their derivatives. Understandably, multiple aryl groups can also be interrupted by short non-aromatic units (e.g., <10% non-H atoms, such as C, N, or O atoms), specifically acenaphthene, fluorene, or 9,9-diarylfluorene, triarylamine, and diaryl ether systems should also be included in the definition of aryl.

[0060] In this invention, "heteroaryl" refers to an aryl group in which at least one carbon atom is replaced by a non-carbon atom, which can be an N atom, an O atom, an S atom, etc. For example, "C3-C30 heteroaryl" refers to a heteroaryl group containing 3 to 30 carbon atoms, and each occurrence can be independently of C3 heteroaryl, C4 heteroaryl, C5 heteroaryl, C6 heteroaryl, C7 heteroaryl, C8 heteroaryl, C9 heteroaryl, C10 heteroaryl, C11 heteroaryl, C12 heteroaryl, C14 heteroaryl, C18 heteroaryl, C20 heteroaryl, C25 heteroaryl, and C30 heteroaryl. Suitable examples include, but are not limited to: furan, benzofuran, thiophene, benzothiophene, pyrrole, pyrazole, triazole, imidazole, oxazole, oxadiazole, thiazole, tetraazole, indole, carbazole, pyrroloimidazole, pyrrolopyrrole, thienopyrrole, thienothiophene, furanolopyrrole, furanolofuran, thienofuran, benzoisoxazole, benzoisothiazolium, benzimazole, pyridine, pyrazine, pyrimidine, triazine, quinoline, isoquinoline, o-diazonyl, quinoxaline, phenanthridine, primidine, quinazoline, and quinazolineone. Understandably, "azaaryl" refers to a heteroaryl group whose non-carbon atom is an nitrogen atom.

[0061] Some examples of the present invention provide an organic compound having the structural features shown in formula (I):

[0062]

[0063] in,

[0064] R1 and R2 are each independently a substituted or unsubstituted C6-C30 aryl, a substituted or unsubstituted C3-C30 heteroaryl, a substituted or unsubstituted C1-C16 alkyl, a substituted or unsubstituted C1-C16 alkoxy, or a substituted or unsubstituted C3-C16 cycloalkyl.

[0065] L is one of a single bond, a substituted or unsubstituted C6-C30 arylene, or a substituted or unsubstituted C3-C30 heteroarylene;

[0066] Z is N;

[0067] R3 and R4 are each independently a substituted or unsubstituted C3-C30 azaaryl group;

[0068] The substituents include one or more of C1-C25 alkyl, C1-C15 alkoxy, C6-C16 aryl, deuterium, F, and CN.

[0069] In some of these examples, at least one of the groups in R1 and R2 contains an N atom. This can increase charge mobility and / or improve stability, thereby enhancing the luminous efficiency and lifetime of the device and reducing the driving voltage.

[0070] In some examples, at least one of R1 and R2 is a C3-C30 aziridine or a CN-substituted C6-C30 aryl group. This is beneficial for improving the luminous efficiency and lifetime of the device, and reducing the driving voltage.

[0071] Furthermore, at least one of R1 and R2 is a C3-C18 aziratriylaryl or a CN-substituted C6-C18 aryl, which is beneficial for improving the luminous efficiency and lifetime of the device and reducing the driving voltage. Even further, at least one of R1 and R2 is a C3-C8 aziratriylaryl or a CN-substituted C6-C8 aryl, which can further improve the luminous efficiency and lifetime of the device and reduce the driving voltage.

[0072] Without limitation, at least one of R1 and R2 is a phenyl group substituted with pyridyl, quinolinyl or CN.

[0073] In some examples, one of R1 and R2 is a C3-C30 azeotropic or a CN-substituted C6-C30 aryl, and the other is a C6-C30 aryl. Without limitation, R1 is a C3-C30 azeotropic or a CN-substituted C6-C30 aryl, and R2 is a C6-C30 aryl.

[0074] In some examples, in CN-substituted C6-C30 aryl groups, the substitution site of CN on the C6-C30 aryl group is the first site, and the substitution site of the phenanthrene group on the C6-C30 aryl group is the second site. The positional relationship between the first site and the second site is adjacent, para, or meta. This is beneficial for improving the luminous efficiency and lifetime of the device and reducing the driving voltage. Furthermore, if the positional relationship between the first site and the second site is meta, it can further improve the luminous efficiency and lifetime of the device and reduce the driving voltage.

[0075] In some of these examples, R1 is one of the following groups:

[0076]

[0077] In some of these examples, R2 is phenyl.

[0078] In some of these examples, L is a substituted or unsubstituted C6–C30 arylene, and the substitution site of the phenanthrene group on L is the third site. The substitution site of the group on L is the fourth site, and the positional relationship between the third and fourth sites is ortho, para, or meta. This is beneficial for improving the luminous efficiency and lifetime of the device, and reducing the driving voltage. Furthermore, if the positional relationship between the third and fourth sites is meta, it can further improve the luminous efficiency and lifetime of the device, and reduce the driving voltage.

[0079] Without limitation, L is a single bond, a substituted or unsubstituted C6–C30 arylene. Further, L is a single bond or a phenylene.

[0080] In some of these examples, L is a single bond or one of the following groups:

[0081]

[0082] In some examples, R3 and R4 are independently substituted or unsubstituted C3–C15 aziridine groups, which helps to improve the luminous efficiency and lifetime of the device and reduce the driving voltage. Furthermore, R3 and R4 are independently C3–C8 aziridine groups, which can further improve the luminous efficiency and lifetime of the device and reduce the driving voltage.

[0083] Without restriction, R3 and R4 can each be pyridyl, quinolinyl, or isoquinolinyl. This can further improve electron transport efficiency.

[0084] In some of these examples, the azaaryl group in R3 and R4 contains one nitrogen atom, and the nitrogen atom is located at the fifth position in the azaaryl group. The substitution site on the aziridine group is the sixth site, and the fifth site is positioned ortho, para, or meta relative to the sixth site. This arrangement is beneficial for improving the luminous efficiency and lifetime of the device, and reducing the driving voltage. Furthermore, the ortho position of the fifth and sixth sites further enhances the luminous efficiency and lifetime of the device, and reduces the driving voltage. In addition, it can form more stable complexes with dopants, thereby improving device efficiency.

[0085] In some of these examples, R3 and R4 are each independently one of the following groups:

[0086]

[0087] In some of these examples, R3 and R4 are the same.

[0088] In some of these examples, the organic compound has one of the structural features shown in formulas (I-1) to (I-5):

[0089]

[0090] Specifically, the organic compounds include, but are not limited to, any one of the following compounds CGL1-CGL99:

[0091]

[0092]

[0093]

[0094]

[0095] Other examples of the present invention provide the application of the organic compounds described above as electron transport materials and / or n-type doped organic materials.

[0096] Understandably, when the organic compound is used as an electron transport material, there is no limitation on the type of device; it can be a classic organic electroluminescent device or a tandem organic electroluminescent device. When the organic compound is used as an n-type dopant, it is typically applied in tandem organic electroluminescent devices.

[0097] Other examples of the present invention provide the use of the organic compounds described above in organic electroluminescent devices, organic solar cells, organic thin-film transistors, organic photodetectors, organic field-effect transistors, organic integrated circuits, or organic photosensors.

[0098] In other examples of the present invention, an organic electroluminescent device is provided, the structure of which is as follows: Figure 1 As shown, it includes a first electrode, a second electrode, and a light-emitting unit (organic semiconductor layer) disposed between the first electrode and the second electrode. The light-emitting unit includes an electron transport layer, which contains at least one of the organic compounds described above. Without limitation, the first electrode is an anode, and the second electrode is a cathode.

[0099] It is also understood that the light-emitting unit may include one or more of the following: an electron injection layer, an electron transport layer, a hole blocking layer, a light-emitting layer, an electron blocking layer, a hole transport layer, and a hole injection layer. Specifically, the structure of the organic electroluminescent device is as follows: Figure 2 As shown, it includes a cathode, an electron injection layer, an electron transport layer, a hole blocking layer, a light-emitting layer, an electron blocking layer, a hole transport layer, a hole injection layer, and an anode, which are stacked in sequence.

[0100] In some of these examples, the electron transport layer also contains dopants.

[0101] In some of these examples, the dopant is a metal complex. The dopant is lithium 8-hydroxyquinoline.

[0102] In some examples, the dopant in the electron transport layer has a mass percentage of 20% to 70%. Specifically, the mass percentage of the dopant in the electron transport layer includes, but is not limited to: 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, and 70%. Furthermore, the mass percentage of the dopant in the electron transport layer is 30% to 60%.

[0103] In other examples of the present invention, a series organic electroluminescent device is provided, comprising a first electrode, a second electrode, and two or more light-emitting units disposed between the first electrode and the second electrode, wherein a charge generation layer is provided between each pair of light-emitting units; the light-emitting unit includes an electron transport layer, and the charge generation layer includes an n-type doped organic layer; the electron transport layer and / or the n-type doped organic layer comprises at least one of the organic compounds described above.

[0104] Understandably, the charge generation layer also includes a p-type doped layer and a spacer layer located between the n-type doped layer and the p-type doped layer.

[0105] Without limitation, taking two light-emitting units as an example, the structure of the series-connected organic electroluminescent device is as follows: Figure 3 As shown, it includes a cathode, an electron injection layer, an electron transport layer, a light-emitting layer 2, an electron blocking layer, a hole transport layer, a p-type doped layer, a spacer layer, an n-type doped layer, an electron transport layer, a light-emitting layer 1, an electron blocking layer, a hole transport layer, a hole injection layer, and an anode, which are stacked in sequence.

[0106] In some of these examples, the n-type doped organic layer also contains a dopant.

[0107] In some of these examples, the dopant is a metal dopant. Examples include one or more of alkali metals, alkaline earth metals, and rare earth metals.

[0108] In some examples, the dopant is one or more of Li, Na, Cs, Mg, Ca, Sr, and Yb. Further, the dopant is one or both of Li and Yb. This can further increase the conductivity of the device.

[0109] In some examples, the dopant accounts for 0.5% to 50% of the mass percentage of the n-type doped organic layer. Specifically, the mass percentage of the dopant in the n-type doped organic layer includes, but is not limited to: 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%. Further, the mass percentage of the dopant in the n-type doped organic layer ranges from 1% to 20%.

[0110] In addition, without limitation, the organic material layer structure in the organic electroluminescent device or the tandem organic electroluminescent device, as described above, can be prepared by vacuum evaporation, molecular beam evaporation, solvent-based dip coating, spin coating, bar coating or inkjet printing. For metal electrodes, evaporation or sputtering methods can be used for preparation.

[0111] Other examples of the present invention also provide a display device, including one or both of the organic electroluminescent device described above and the tandem organic electroluminescent device described above.

[0112] The following are specific examples.

[0113] Example 1: Synthesis of CGL1

[0114]

[0115] The synthesis route is as follows:

[0116]

[0117] The operation steps are as follows:

[0118] Step 1: Synthesize PT1:

[0119] After purging the four-necked flask with nitrogen, toluene (100 mL), p-bromocyanobenzene (10 g), diphenazine boronate (16.74 g), PdCl2(dppf)·CH2Cl2 (100 mg), and potassium acetate (13.48 g) were added sequentially. The mixture was stirred at 78 °C for 2 h, washed with water, extracted with ethyl acetate, dried over anhydrous sodium sulfate, passed through a Flash column, and the solvent was removed by vacuum distillation of the column solution. The mixture was then slurried with n-hexane and filtered to obtain 8.68 g of white solid.

[0120] Step 2: Synthesize PT2:

[0121] After purging the four-necked flask with nitrogen, toluene (150 mL), 4'-bromo-2,2',6',2'-terpyridine (15 g), bipinane diboryl ester (14.64 g), PdCl2(dppf)·CH2Cl2 (150 mg), and potassium acetate (11.79 g) were added sequentially. The mixture was stirred at 78 °C for 2 h, washed with water, extracted with ethyl acetate, dried over anhydrous sodium sulfate, passed through a Flash column, and the solvent was removed by vacuum distillation of the column solution. The mixture was then slurried with n-hexane and filtered to obtain 10.53 g of white solid.

[0122] Step 3: Synthesize PT3:

[0123] After purging the four-necked flask with nitrogen, toluene (50 mL), ethanol (25 mL), water (12.5 mL), 2-chloro-9-iodo-10-phenylphenanthrene (14.80 g), PT1 (8.59 g), Pd(PPh3)4 (140 mg), and sodium bicarbonate (7.50 g) were added sequentially. The mixture was stirred at 78 °C for 2 h, washed with water, extracted with ethyl acetate, dried over anhydrous sodium sulfate, passed through a Flash column, and the solvent was removed by vacuum distillation of the column solution. The solution was then slurried with n-hexane and filtered to obtain 7.98 g of white solid.

[0124] Step 4: Synthesize CGL1:

[0125] After purging the four-necked flask with nitrogen, toluene (80 mL), PT3 (7.79 g), PT2 (7.54 g), palladium acetate (70 mg), X-PHOS (140 mg), and potassium carbonate (6.90 g) were added sequentially. The mixture was stirred at 78 °C for 2 h. After washing with water, extraction with ethyl acetate, drying with anhydrous sodium sulfate, and passing through a Flash column, the solvent was removed by vacuum distillation of the column solution, and the mixture was slurried with n-hexane and filtered to obtain 7.97 g of white solid.

[0126] 1 H NMR(500MHz,Chloroform-d)δ8.93(d,J=1.6Hz,1H),8.88(d,J=7.5Hz,1H),8.7 7(dd,J=7.5,1.5Hz,2H),8.66(dd,J=7.5,1.6Hz,2H),8.18(s,2H),8.16-8.10(m ,1H),8.07(dd,J=7.5,1.5Hz,1H),7.90-7.82(m,4H),7.80-7.73(m,1H),7.65- 7.59(m,2H),7.55-7.42(m,6H),7.40-7.33(m,1H),7.19(td,J=7.5,1.5Hz,2H).

[0127] Example 2: Synthesis of CGL4

[0128]

[0129] The synthesis route is as follows:

[0130]

[0131] The synthesis steps are as follows:

[0132] Step 1: Synthesize PT1:

[0133] PT4 was synthesized using the same method as step 1 of Example 1, yielding 10.34 g of white solid.

[0134] Step 2: Synthesize PT2:

[0135] PT5 was synthesized using the same method as step 2 of Example 1, yielding 9.84 g of a white solid.

[0136] Step 3: Synthesize PT3:

[0137] PT6 was synthesized using the same method as step 3 of Example 1, yielding 7.89 g of a white solid.

[0138] Step 4: Synthesize CGL4:

[0139] CGL4 was synthesized using the same method as step 4 of Example 1, yielding 7.98 g of white solid.

[0140] 1 H NMR(500MHz,Chloroform-d)δ8.94(d,J=1.6Hz,1H),8.88(d,J=7.5Hz,1H),8.77(dd,J=7. 5,1.5Hz,2H),8.66(dd,J=7.5,1.6Hz,2H),8.18(s,2H),8.17-8.11(m,1H),8.07(dd,J=7. 5,1.5Hz,1H),7.95(t,J=1.5Hz,1H),7.87(td,J=7.5,1.5Hz,2H),7.80-7.74(m,2H),7.73 (dt,J=7.5,1.6Hz,1H),7.60-7.42(m,7H),7.40-7.33(m,1H),7.19(td,J=7.5,1.5Hz,2H).

[0141] Example 3: Synthesis of CGL7

[0142]

[0143] The synthesis route is as follows:

[0144]

[0145] The synthesis steps are as follows:

[0146] Step 1: Synthesize PT7:

[0147] PT7 was synthesized using the same method as step 1 in Example 1, yielding 7.56 g of a white solid.

[0148] Step 2: Synthesize PT8:

[0149] PT8 was synthesized using the same method as step 2 of Example 1, yielding 10.78 g of a white solid.

[0150] Step 3: Synthesize PT9:

[0151] PT9 was synthesized using the same method as step 3 in Example 1, yielding 8.24 g of a white solid.

[0152] Step 4: Synthesize CGL7:

[0153] CGL7 was synthesized using the same method as step 4 of Example 1, yielding 6.84 g of white solid.

[0154] 1 H NMR(500MHz,Chloroform-d)δ8.95(d,J=1.7Hz,1H),8.91(d,J=1.5Hz,1H),8.88(d,J= 7.5Hz,1H),8.77(dd,J=7.5,1.5Hz,2H),8.65(ddd,J=14.5,7.5,1.6Hz,3H),8.18(s,2H ),8.17-8.10(m,1H),8.07(dd,J=7.5,1.5Hz,1H),7.93(dt,J=7.5,1.5Hz,1H),7.85(td ,J=7.5,1.5Hz,2H),7.84-7.78(m,1H),7.57-7.33(m,8H),7.19(td,J=7.5,1.7Hz,2H).

[0155] Example 4: Synthesis of CGL17

[0156]

[0157] The synthesis route is as follows:

[0158]

[0159] The synthesis steps are as follows:

[0160] Step 1: Synthesize PT10:

[0161] PT10 was synthesized using the same method as step 1 in Example 1, yielding 8.53 g of a white solid.

[0162] Step 2: Synthesize PT11:

[0163] PT11 was synthesized using the same method as step 2 of Example 1, yielding 7.31 g of a white solid.

[0164] Step 3: Synthesize PT12:

[0165] PT12 was synthesized using the same method as step 3 in Example 1, yielding 8.12 g of a white solid.

[0166] Step 4: Synthesize CGL17:

[0167] CGL17 was synthesized using the same method as step 4 of Example 1, yielding 6.53 g of white solid.

[0168] 1 H NMR(500MHz,Chloroform-d)δ8.77(dd,J=7.5,1.5Hz,2H),8.66(dd,J=7.5,1.6Hz,2H),8.54(dd,J= 7.3,1.7Hz,1H),8.23-8.18(m,1H),8.14(dd,J=7.4,1.6Hz,1H),8.04(dd,J=7.5,1.5Hz,1H),7.93-

[0169] 7.86(m,4H),7.89-7.83(m,2H),7.84(d,J=1.2Hz,1H),7.65-7.59(m,2H),7.55-7.42(m,6H),7.40-7.33(m,1H),7.19(td,J=7.5,1.5Hz,2H).

[0170] Example 5: Synthesis of CGL49

[0171]

[0172] The synthesis route is as follows:

[0173]

[0174] The synthesis steps are as follows:

[0175] Step 1: Synthesize PT13:

[0176] PT13 was synthesized using the same method as step 1 in Example 1, yielding 9.85 g of a white solid.

[0177] Step 2: Synthesize PT14:

[0178] PT14 was synthesized using the same method as step 2 of Example 1, yielding 6.58 g of a white solid.

[0179] Step 3: Synthesize PT15:

[0180] PT15 was synthesized using the same method as step 3 in Example 1, yielding 7.25 g of a white solid.

[0181] Step 4: Synthesize CGL49:

[0182] CGL49 was synthesized using the same method as step 4 of Example 1, yielding 5.63 g of white solid.

[0183] 1 H NMR(500MHz,Chloroform-d)δ8.90(dd,J=11.3,1.6Hz,2H),8.81(d,J=7.5Hz,1H),8.77(dd,J=7.5,1.5H z,2H),8.65(ddd,J=14.3,7.5,1.5Hz,3H),8.17-8.10(m,1H),7.93(dt,J=7.3,1.5Hz,1H),7.91(s,2H), 7.87(td,J=7.5,1.5Hz,2H),7.80(ddd,J=15.4,7.1,1.8Hz,2H),7.67-7.58(m,4H),7.53(ddd,J=7.3,4. 7,1.8Hz,4H),7.48-7.42(m,2H),7.40(t,J=7.5Hz,1H),7.37-7.30(m,1H),7.19(td,J=7.5,1.5Hz,2H).

[0184] Example 6: Synthesis of CGL61

[0185]

[0186] The synthesis route is as follows:

[0187]

[0188] The synthesis steps are as follows:

[0189] Step 1: Synthesize PT16:

[0190] PT16 was synthesized using the same method as step 1 in Example 1, yielding 8.65 g of a white solid.

[0191] Step 2: Synthesize PT17:

[0192] PT17 was synthesized using the same method as step 2 of Example 1, yielding 7.89 g of a white solid.

[0193] Step 3: Synthesize PT18:

[0194] PT18 was synthesized using the same method as step 3 in Example 1, yielding 9.51 g of a white solid.

[0195] Step 4: Synthesize CGL61:

[0196] CGL61 was synthesized using the same method as step 4 of Example 1, yielding a white solid 7.21.

[0197] 1 H NMR(500MHz,Chloroform-d)δ8.91(d,J=1.4Hz,1H),8.88(d,J=1.5Hz,1H),8.82(d,J=7.5Hz,1H), 8.77(dd,J=7.5,1.5Hz,2H),8.65(ddd,J=14.3,7.5,1.5Hz,3H),8.18(t,J=1.5Hz,1H),8.14(s,2H ),8.14(dd,J=7.0,2.0Hz,1H),7.93(dt,J=7.3,1.5Hz,1H),7.87(td,J=7.5,1.5Hz,2H),7.85-7.7 6(m,3H),7.57-7.42(m,8H),7.40(t,J=7.5Hz,1H),7.37-7.30(m,1H),7.19(td,J=7.5,1.5Hz,2H).

[0198] Example 7: Synthesis of CGL63

[0199]

[0200] The synthesis route is as follows:

[0201]

[0202] The synthesis steps are as follows:

[0203] Step 1: Synthesize PT19:

[0204] PT19 was synthesized using the same method as step 1 in Example 1, yielding 9.10 g of a white solid.

[0205] Step 2: Synthesize PT20:

[0206] PT20 was synthesized using the same method as step 2 of Example 1, yielding 7.52 g of white solid.

[0207] Step 3: Synthesize PT21:

[0208] PT21 was synthesized using the same method as step 3 in Example 1, yielding 7.34 g of a white solid.

[0209] Step 4: Synthesize CGL63:

[0210] CGL63 was synthesized using the same method as step 4 of Example 1, yielding 9.63 g of a white solid.

[0211] 1 H NMR(500MHz,Chloroform-d)δ8.91(d,J=1.4Hz,1H),8.88(d,J=1.5Hz,1H),8.82(d,J=7.7Hz,1H),8.67-8.61(m,5H),8.23-8.16(m,5H),8.16-8.12(m,1H ),8.00(s,2H),7.93(dt,J=7.3,1.5Hz,1H),7.84-7.78(m,2H),7.69(dt,J=7 .1,1.6Hz,1H),7.57-7.42(m,8H),7.40(t,J=7.5Hz,1H),7.37-7.30(m,1H).

[0212] Example 8:

[0213]

[0214] The synthesis route is as follows:

[0215]

[0216] The synthesis steps are as follows:

[0217] Step 1: Synthesize PT22:

[0218] PT22 was synthesized using the same method as step 1 in Example 1, yielding 8.63 g of a white solid.

[0219] Step 2: Synthesize PT23:

[0220] PT23 was synthesized using the same method as step 2 of Example 1, yielding 7.86 g of a white solid.

[0221] Step 3: Synthesize PT24:

[0222] PT24 was synthesized using the same method as step 3 in Example 1, yielding 7.56 g of a white solid.

[0223] Step 4: Synthesize CGL100:

[0224] CGL100 was synthesized using the same method as step 4 of Example 1, yielding 6.89 g of white solid.

[0225] 1 H NMR(500MHz,Chloroform-d)δ8.89(dd,J=12.8,1.5Hz,2H),8.82(d,J=7.7Hz,1H),8.6 4(dd,J=7.5,1.4Hz,1H),8.50-8.45(m,3H),8.19(dd,J=7.5,1.7Hz,2H),8.15(s,2H), 8.16-8.11(m,1H),8.00(dd,J=7.5,1.8Hz,2H),7.94-7.86(m,4H),7.83-7.76(m,2H), 7.73(td,J=7.5,1.5Hz,2H),7.60-7.47(m,8H),7.43-7.36(m,3H),7.39-7.30(m,1H).

[0226] Example 9:

[0227]

[0228] The synthesis route is as follows:

[0229]

[0230] The synthesis steps are as follows:

[0231] Step 1: Synthesize PT25:

[0232] PT25 was synthesized using the same method as step 1 in Example 1, yielding 8.56 g of a white solid.

[0233] Step 2: Synthesize PT26:

[0234] PT26 was synthesized using the same method as step 2 of Example 1, yielding 10.52 g of white solid.

[0235] Step 3: Synthesize PT27:

[0236] PT27 was synthesized using the same method as step 3 in Example 1, yielding 8.96 g of a white solid.

[0237] Step 4: Synthesize CGL101:

[0238] CGL101 was synthesized using the same method as step 4 of Example 1, yielding 6.38 g of white solid.

[0239] 1H NMR(500MHz,Chloroform-d)δ8.96(d,J=1.5Hz,2H),8.92(t,J=1.5Hz,1H),8.88(d,J=7.5Hz, 1H),8.77(dd,J=7.5,1.5Hz,2H),8.66(dd,J=7.5,1.5Hz,2H),8.18(s,2H),8.14(dd,J=7.5,1. 5Hz,1H),8.09(ddd,J=14.2,7.5,1.5Hz,2H),7.87(td,J=7.5,1.5Hz,2H),7.82(dd,J=7.3,1.6 Hz,1H),7.78-7.69(m,2H),7.60-7.41(m,7H),7.37-7.30(m,1H),7.19(td,J=7.5,1.5Hz,2H).

[0240] Device fabrication method:

[0241] like Figure 3 As shown, a tandem organic electroluminescent device (containing two light-emitting units) is fabricated. The device structure includes a substrate 1 and light-emitting devices sequentially formed on the substrate 1, as detailed below:

[0242] 1-Anode / substrate, 2-Hole injection layer, 3-Hole transport layer, 4-Electron blocking layer, 5-Light emitting layer 1, 6-Electron transport layer, 7-n-type doped layer, 8-Spacer layer, 9-p-type doped layer, 10-Hole injection layer, 11-Electron blocking layer, 12-Hole transport layer, 13-Light emitting layer 2, 14-Electron injection layer, 15-Cathode.

[0243] The transparent conductive ITO glass substrate 1 (with an anode on it) (China Southern Glass Group Co., Ltd.) was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, and then washed in sequence with ethanol, acetone and deionized water. It was baked in a clean environment until all moisture was removed, cleaned with ultraviolet photosynthetic ozone, and then treated with oxygen plasma for 30 seconds.

[0244] The glass substrate with the anode was placed in a vacuum chamber, and a vacuum was drawn. A 10 nm thick HT:3% p-dopant layer was deposited on ITO as a hole injection layer 2 at a deposition rate of 0.1 nm / s.

[0245] Compound HT was deposited on the hole injection layer to form a 14 nm thick hole transport layer 3, with a deposition rate of 0.1 nm / s.

[0246] An EB (10 nm) layer was deposited on top of the hole injection layer as an electron blocking layer 4 at a deposition rate of 0.1 nm / s.

[0247] BH:BD (20nm) was deposited on the electron blocking layer as the light-emitting layer 1 5, wherein BH is the host light-emitting material and BD is doped with 2% by volume. The deposition rate was 0.1nm / s.

[0248] TPBi:Liq (volume ratio 5:5, 30nm) was deposited on the luminescent layer as electron transport layer 6 at a deposition rate of 0.1nm / s.

[0249] The host material compound Yb (mass ratio 95:5, 10 nm) was deposited on the electron transport layer as an n-type doped layer 7 at a deposition rate of 0.1 nm / s.

[0250] Ag (5 nm) was deposited as a spacer layer 8 on the n-type doped layer at a deposition rate of 0.1 nm / s.

[0251] HT:p-dopant (10 nm) was deposited on the spacer layer as a p-type doped layer 9.

[0252] HT was deposited on the p-type doped layer to form a 33 nm thick hole transport layer 10 at a deposition rate of 0.1 nm / s.

[0253] An EB (10 nm) layer was deposited on the hole injection layer as an electron blocking layer 11 at a deposition rate of 0.1 nm / s.

[0254] BH:BD (20nm) was deposited on the electron blocking layer as the light-emitting layer 2 12, where BH is the host light-emitting material and BD is doped with 2% by volume. The deposition rate was 0.1nm / s.

[0255] TPBi:Liq (volume ratio 5:5, 30nm) was used as electron transport layer 13 on the light-emitting layer, and the evaporation rate was 0.1nm / s.

[0256] Yb (1 nm) was deposited as the electron injection layer 14 in electron transport at a deposition rate of 0.1 nm / s.

[0257] Ag:Mg (volume ratio 9:1, 140 nm) was deposited on the electron injection layer as the cathode 15.

[0258] The structural formulas of the materials described in the device are as follows, and all of them are existing known materials obtained from market procurement.

[0259]

[0260]

[0261] The difference between Application Examples 1-9 and Comparative Examples 1 and 2 lies in the different host material compounds used in the n-type doped layer 7. Application Examples 1-9 respectively contain host material compounds CGL1, CGL4, CGL7, CGL17, CGL49, CGL61, CGL63, CGL100, and CGL101, as shown in Table 1 below:

[0262] Table 1

[0263] Application Example 1 Example 1 (CGL1) Application Example 2 Example 2 (CGL4) Application Example 3 Example 3 (CGL7) Application Example 4 Example 4 (CGL17) Application Example 5 Example 5 (CGL49) Application Example 6 Example 6 (CGL61) Application Example 7 Example 7 (CGL63) Application Example 8 Example 8 (CGL100) Application Example 9 Example 9 (CGL101) Comparative Example 1 BCP Comparative Example 2 Bphen

[0264] Device performance testing

[0265] The fabricated device was tested using a CS2000 spectrometer for its operating voltage, current efficiency, power efficiency, and performance at 30 mA / cm². 2 The lifetime (T95) during which brightness decays to 95% of the original brightness under current density. Test data are shown in Table 2 below:

[0266] Table 2

[0267]

[0268]

[0269] Comparing the data from Application Examples 1-9 and Comparative Examples 1-2, it can be seen that the device prepared by the present invention using a compound of general formula I as the n-type doped host material for the charge generation layer has improved current efficiency and power efficiency. More importantly, the lifetime is also significantly improved, greatly expanding the application of tandem organic electroluminescent devices in automotive displays.

[0270] like Figure 2 As shown, a single-layer (classical) organic electroluminescent device is fabricated. The device structure includes a substrate 1 and light-emitting devices sequentially formed on the substrate 1, as detailed below:

[0271] 1-Anode / substrate, 2-Hole injection layer, 3-Hole transport layer, 4-Electron blocking layer, 5-Light emitting layer 1, 6-Electron transport layer, 7-Electron injection layer, 8-Cathode.

[0272] The transparent conductive ITO glass substrate 1 (with an anode on it) (China Southern Glass Group Co., Ltd.) was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, and then washed in sequence with ethanol, acetone and deionized water. It was baked in a clean environment until all moisture was removed, cleaned with ultraviolet photosynthetic ozone, and then treated with oxygen plasma for 30 seconds.

[0273] The glass substrate with the anode was placed in a vacuum chamber, and a vacuum was drawn. A 10 nm thick HT:3% p-dopant layer was deposited on ITO as a hole injection layer 2 at a deposition rate of 0.1 nm / s.

[0274] Compound HT was deposited on the hole injection layer to form a 14 nm thick hole transport layer 3, with a deposition rate of 0.1 nm / s.

[0275] An EB (10 nm) layer was deposited on top of the hole injection layer as an electron blocking layer 4 at a deposition rate of 0.1 nm / s.

[0276] BH:BD (20nm) was deposited on the electron blocking layer as the light-emitting layer 5, where BH is the host light-emitting material and BD is doped with 2% by volume. The deposition rate was 0.1nm / s.

[0277] An electron transport material, Liq (mass ratio 5:5, 30 nm), was deposited on the luminescent layer as electron transport layer 6 at a deposition rate of 0.1 nm / s.

[0278] Yb (1 nm) was deposited as the electron injection layer 7 in electron transport at a deposition rate of 0.1 nm / s.

[0279] Ag:Mg (volume ratio 9:1, 140 nm) was deposited on the electron injection layer as the cathode 8.

[0280] The vapor-deposited substrate is then encapsulated. First, a UV adhesive coating process is used to coat the cleaned cover plate with UV adhesive using an adhesive coating equipment. Then, the coated cover plate is moved to the lamination section, and the vapor-deposited substrate is placed on top of the cover plate. Finally, the substrate and cover plate are laminated under the action of a bonding equipment, while the UV adhesive is cured by light.

[0281] The difference between Application Examples 10-15 and Comparative Examples 3 and 4 lies in the electron transport materials used in the electron transport layer 6. Application Examples 10-15 respectively contain electron transport material compounds CGL1, CGL4, CGL7, CGL17, CGL49, and CGL61, while Comparative Examples 3-4 respectively contain electron transport material compounds TPBi and ET1. TPBi is a commercially known material, and ET1 is a compound in prior art CN111170993A, with the following structural formula:

[0282]

[0283] Specific implementation examples are shown in Table 3 below:

[0284] Table 3

[0285] Application Example 10 Example 1 (CGL1) Application Example 11 Example 2 (CGL4) Application Example 12 Example 3 (CGL7) Application Example 13 Example 4 (CGL17) Application Example 14 Example 5 (CGL49) Application Example 15 Example 6 (CGL61) Comparative Example 3 TPBi Comparative Example 4 ET1

[0286] Device performance testing

[0287] The fabricated device was tested using a CS2000 spectrometer for its operating voltage, current efficiency, power efficiency, and performance at 30 mA / cm². 2 The lifetime (T95) during which brightness decays to 95% of the original brightness under current density. Test data are shown in Table 4 below:

[0288] Table 4

[0289]

[0290]

[0291] The compound of general formula I of this invention is used as an electron transport material in organic electroluminescent devices. Compared with TPBi and ET1, it reduces the operating voltage, improves efficiency, and greatly increases lifespan.

[0292] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0293] The embodiments described above are merely illustrative of several implementations of the present invention, designed to facilitate a detailed understanding of the technical solutions of the present invention, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided by the present invention through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this invention patent should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. An organic compound having the structural features shown in formula (I): （I） in, In R1 and R2, one is a C5-C9 azeotropic or a CN-substituted C6-C8 aryl group, and the other is a C6-C8 aryl group. In the CN-substituted C6-C8 aryl group, the substitution site of CN on the C6-C8 aryl group is the first site, and the substitution site of the phenanthrene group on the C6-C8 aryl group is the second site. The positional relationship between the first site and the second site is para or meta. L is a single bond or an unsubstituted phenylene; Z is N; R3 and R4 are independently pyridyl, quinolinyl, or isoquinolinyl.

2. The organic compound according to claim 1, characterized by One of R1 and R2 is a pyridyl, quinolinyl, or CN-substituted phenyl group, and the other is a phenyl group.

3. The organic compound according to claim 1, wherein In the C6-C8 aryl groups substituted with CN, the positional relationship between the first site and the second site is metaposition.

4. The organic compound according to claim 1, characterized in that, L is unsubstituted phenylene, the substitution position of phenanthryl group on L is the third position, the substitution position of the group on L is the fourth position, the positional relationship between the third position and the fourth position is para or meta.

5. The organic compound according to claim 4, characterized by The positional relationship between the third and fourth sites is interposition.

6. The organic compound according to claim 1, characterized in that, R3, R4contains 1 nitrogen, the position of the nitrogen in R3, R4is the fifth position, the substitution position of the group on R3, R4is the sixth position, and the positional relationship between the fifth position and the sixth position is ortho, para or meta.

7. The organic compound according to claim 6, characterized in that, The fifth and sixth sites are adjacent to each other.

8. The organic compound according to claim 1, characterized in that, The organic compound has one of the structural features shown in formulas (I-1) to (I-5): (I-1); (I-2); (I-3); (I-4) Someone (I-5).

9. The organic compound according to claim 1, characterized in that, The organic compound includes one of the following: , , , , , , , and .

10. The use of the organic compound according to any one of claims 1 to 9 as an electron transport material.

11. The use of the organic compound according to any one of claims 1 to 9 as an electron transport material in organic electroluminescent devices.

12. An organic electroluminescent device, characterized in that, It includes a first electrode, a second electrode, and a light-emitting unit disposed between the first electrode and the second electrode. The light-emitting unit includes an electron transport layer, and the electron transport layer contains at least one of the organic compounds according to any one of claims 1 to 9.

13. The organic electroluminescent device according to claim 12, characterized in that, The electron transport layer also includes a dopant, which is a metal complex.

14. The organic electroluminescent device according to claim 13, characterized in that, The dopant has one or more of the following characteristics: (1) The dopant is lithium 8-hydroxyquinoline; (2) The mass percentage of the dopant in the electron transport layer is 20% to 70%.

15. The organic electroluminescent device according to claim 14, characterized in that, The dopant in the electron transport layer has a mass percentage of 30% to 60%.

16. A series-connected organic electroluminescent device, characterized in that, It includes a first electrode, a second electrode, and two or more light-emitting units disposed between the first electrode and the second electrode, with a charge generation layer between each pair of light-emitting units; The light-emitting unit includes an electron transport layer, and the charge-generating layer includes an n-type doped organic layer. The electron transport layer comprises at least one of the organic compounds according to any one of claims 1 to 9.

17. The tandem organic electroluminescent device according to claim 16, characterized in that, The n-type doped organic layer further includes a dopant, which is a metal dopant.

18. The tandem organic electroluminescent device according to claim 17, characterized in that, The dopant has one or more of the following characteristics: (1) The dopant is one or more of alkali metals, alkaline earth metals and rare earth metals; (2) The mass percentage of the dopant in the n-type doped organic layer is 0.5% to 50%.

19. The tandem organic electroluminescent device according to claim 18, characterized in that, The dopant has one or more of the following characteristics: (1) The dopant is one or more of Li, Na, Cs, Mg, Ca, Sr and Yb; (2) The mass percentage of the dopant in the n-type doped organic layer is 1% to 20%.

20. A display device, characterized in that, It includes at least one of the organic electroluminescent devices according to any one of claims 12 to 15 and the tandem organic electroluminescent devices according to any one of claims 16 to 19.

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