Laminated organic light-emitting device and preparation method and application thereof

Abstract

The invention relates to the technical field of organic light-emitting display, in particular to a laminated organic light-emitting device and a preparation method and application thereof. The laminated organic light-emitting device comprises at least one compound as shown in the formula (I) as a charge generation layer material, and further comprises at least one compound as shown in the formula (II) as a hole transport layer material, and the two types of materials of the formula (I) and the formula (II) contained in the device structure have high inter-atomic bond energy and good thermal stability, and can be applied to the field of organic light-emitting devices. And solid state accumulation between molecules is facilitated, an appropriate energy level exists between adjacent levels, and injection and migration of excitons are facilitated. The laminated device can effectively reduce the driving voltage of the organic light-emitting device, improve the stability of the device and prolong the service life of the device. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the technical field of organic light-emitting display, and particularly to a stacked organic electroluminescent device, a preparation method thereof, and an application thereof. Background Art

[0002] Electroluminescence (EL) refers to the phenomenon that a luminescent material emits light under the action of an electric field, being excited by current and voltage. It is a luminescence process that directly converts electrical energy into light energy. Organic electroluminescent displays (hereinafter referred to as OLEDs) have a series of advantages such as self-luminescence, low-voltage DC drive, all-solid state, wide viewing angle, light weight, simple composition and process. Compared with liquid crystal displays, organic electroluminescent displays do not require a backlight, have a large viewing angle and low power, and their response speed can reach 1000 times that of liquid crystal displays, while their manufacturing cost is lower than that of liquid crystal displays with the same resolution. Therefore, organic electroluminescent devices have very broad application prospects.

[0003] With the continuous advancement of OLED technology in the two major fields of lighting and display, people pay more attention to the research on high-efficiency organic materials that affect the performance of OLED devices. An organic electroluminescent device with high efficiency and long life is usually the result of an optimized combination of a device structure and various organic materials, which provides great opportunities and challenges for chemists to design and develop functional materials with various structures. Stacked devices can effectively improve the working life of the device, and thus belong to the research hotspots in recent years. Developing high-performance charge generation layer materials and simultaneously selecting and matching luminescent units are the research focuses. Summary of the Invention

[0004] The purpose of the present invention is to provide a stacked organic electroluminescent device, a preparation method thereof, and an application thereof, so as to improve the working efficiency and extend the service life of the organic electroluminescent device.

[0005] The purpose of the first aspect of the present invention is to provide a stacked organic electroluminescent device, which comprises at least one compound of formula (I) as a charge generation layer material, and further comprises at least one compound of formula (II) as a hole transport layer material,

[0006]

[0007] In formula (I), L1 and L2 are selected from a chemical bond, an unsubstituted or Rc-substituted C6-C 30 arylene, an unsubstituted or Rc-substituted C3-C 30 heteroarylene; X 1 -X 10 is selected from CR or N, and R is selected from hydrogen, deuterium, an unsubstituted or Rc-substituted C6-C 30An aryl group, a C3-C that is unsubstituted or substituted by Rc 30 A heteroaryl group, and adjacent Rs may be connected to form a ring, and at least one of X1-X 10 is N; the heteroatoms on the heteroaryl group or the heteroarylene group are each independently selected from O, S or N;

[0008]

[0009] In formula (II), R 1 -R 2 are each independently selected from an aromatic group of C6-C 30 or a heteroaryl group of C3-C 30 and at least one is selected from a C 12 -C 20 aromatic group or heteroaryl group, R 1 , R 2 may be connected to form a ring; R 3 -R 7 are each independently selected from hydrogen, deuterium, a C1-C4 alkane, a C5-C 10 cycloalkane, an aromatic group of C6-C 30 or a heteroaryl group of C3-C 30 , and adjacent substituents can be connected to form a ring; R 8 -R 9 are each independently selected from hydrogen, an aromatic group of C6-C 30 or a heteroaryl group of C3-C 30 , and at least one is not H; the heteroatoms on the heteroaryl group are each independently selected from O, S or N; the hydrogen atoms on the aromatic group and the heteroaryl group can each independently be substituted by Ra, and the Ra are each independently selected from deuterium, halogen, nitro, cyano, an alkyl group of C1-C4, a C5-C 20 cycloalkyl group, phenyl group, biphenyl group, terphenyl group or naphthyl group.

[0010] Furthermore, the compound of formula (I) is selected from the compounds shown in A1 to A30 below:

[0011]

[0012]

[0013] Still further, the compound of formula (II) is selected from the compounds shown in B1 to B25 below:

[0014] .

[0016] Further, the stacked organic electroluminescent device includes: a first electrode, a second electrode facing the first electrode, m light-emitting units stacked between the first electrode and the second electrode, and m - 1 charge generation layers, where m is an integer equal to or greater than 2; each of the light-emitting units includes at least one light-emitting layer, the charge generation layers are between two adjacent light-emitting units, each of the charge generation layers includes an n-type charge generation layer and a p-type charge generation layer, the maximum emission wavelength of the light emitted by at least one of the light-emitting units is different from the maximum emission wavelength of the light emitted by at least one other light-emitting unit, at least one of the n-type charge generation layers includes at least one compound of formula (I) and a metal-containing material, at least one of the light-emitting units further includes a hole transport layer on its first electrode side, and the hole transport layer includes at least one compound of formula (II).

[0017] Further, the metal-containing material is at least one of a metal, a metal complex, and combinations thereof.

[0018] Still further, the metal-containing material is Li and / or Yb, and the mass ratio of the metal-containing material to the compound of formula (I) in the n-type charge generation layer is 0.5 - 15:85 - 99.5.

[0019] Further, the thickness of the charge generation layer is 10 nm - 30 nm, and the thickness of the hole transport layer is 60 nm - 140 nm.

[0020] An object of the second aspect of the present invention is to provide a method for manufacturing the above-mentioned stacked organic electroluminescent device, including the following steps:

[0021] (1) Clean the reflective anode on the top-emitting organic electroluminescent device substrate, and in a cleaning machine, perform steps such as chemical washing, water washing, brushing, high-pressure water washing, and air knife, and then perform heat treatment;

[0022] (2) Vacuum deposit a hole injection material on the reflective anode as the first hole injection layer;

[0023] (3) Vacuum deposit a hole transport material on the first hole injection layer as the first hole transport layer;

[0024] (4) Vacuum deposit a first light-emitting layer on the first hole transport layer, and the light-emitting layer contains a host material and a guest material;

[0025] (5) Vacuum deposit an electron transport material on the first light-emitting layer as the first electron transport layer;

[0026] (6) Vacuum deposit a charge generation material on the first electron transport layer as the charge generation layer;

[0027] (7) A hole injection material is vacuum-evaporated on the charge generation layer as the second hole injection layer;

[0028] (8) A hole transport material is vacuum-evaporated on the second hole injection layer as the second hole transport layer;

[0029] (9) A second light-emitting layer is vacuum-evaporated on the second hole transport layer, and the light-emitting layer contains a host material and a guest material;

[0030] (10) An electron transport material is vacuum-evaporated on the second light-emitting layer as the second electron transport layer;

[0031] (11) An electron injection material is vacuum-evaporated on the second electron transport layer as the electron injection layer;

[0032] (12) A cathode material is vacuum-evaporated on the electron injection layer as the cathode.

[0033] An object of the third aspect of the present invention is to provide a display device, which includes the above-mentioned stacked organic electroluminescent device.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] The compound provided by the present invention includes: a first electrode; a second electrode; a light-emitting unit stacked between the first electrode and the second electrode and including at least one light-emitting layer; and a charge generation layer formed by a disubstituted phenanthroline compound between two adjacent light-emitting units. At the same time, the structure includes a hole transport layer material used in combination. It has the parent structure of disubstituted phenanthroline, has high-efficient charge generation ability, can effectively improve the device efficiency, and at the same time, when used in combination with the second type of hole transport layer material, can effectively enhance the charge transport function of the device and improve the efficiency and lifespan of the device. In addition, the two materials used in combination in the present invention simultaneously have high bond energy between atoms, have good thermal stability, and are beneficial to the solid-state packing between molecules, and can achieve good luminous efficiency and service life in the organic electroluminescent device. The compound of the present invention has a large conjugated plane, is beneficial to molecular packing, shows good thermodynamic stability, and shows a long lifespan in the device. The display device provided by the present invention has excellent display effects.

[0036] Of course, it is not necessary for any product or method implementing the present invention to achieve all the above-mentioned advantages simultaneously. Description of the Drawings

[0037] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other embodiments based on these drawings.

[0038] Figure 1 It is a schematic structural diagram of a typical organic electroluminescent device 20. Each part is respectively: 21, a substrate; 22, a reflective anode; 231, a first hole injection layer; 241, a first hole transport layer; 251, a first light-emitting layer; 261, a first electron transport layer; 27, a charge generation layer; 232, a second hole injection layer; 242, a second hole transport layer; 252, a second light-emitting layer; 262, a second electron transport layer; 28, an electron injection layer; 29, a cathode. Detailed implementation manners

[0039] The following will clearly and completely describe the technical solutions in the present invention with reference to the drawings in the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art based on the present invention belong to the scope of protection of the present invention.

[0040] The organic electroluminescent device of the present invention can be a light-emitting device with a top-emitting structure, and can sequentially include an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, a transparent or semi-transparent cathode on the substrate.

[0041] In addition, an electron blocking layer can be provided between the hole transport layer and the light-emitting layer, a hole blocking layer can be provided between the light-emitting layer and the electron transport layer, and a light extraction layer can be provided on the transparent electrode on the light-emitting side. However, the structure of the organic electroluminescent device of the present invention is not limited to the above specific structure. If necessary, the above layers can be omitted or added. The present invention has no particular limitation on the thickness of the above layers, as long as the object of the present invention can be achieved. For example, the organic electroluminescent device can sequentially include an anode made of metal, a hole injection layer (5 nm to 20 nm), a hole transport layer (80 nm to 140 nm), an electron blocking layer (5 nm to 20 nm), a light-emitting layer (150 nm to 400 nm), a hole blocking layer (5 nm to 20 nm), an electron transport layer (300 nm to 800 nm), an electron injection layer (5 nm to 20 nm), a transparent or semi-transparent cathode, and a light extraction layer (50 nm to 90 nm) on the substrate.

[0042] The organic light-emitting device provided by the present invention includes: a first electrode; a second electrode; a light-emitting unit stacked between the first electrode and the second electrode and including at least one light-emitting layer; and a charge generation layer formed of a disubstituted phenanthroline compound included between two adjacent light-emitting units, and meanwhile, the structure during this period includes a hole-transporting layer material used in combination.

[0043] In one or more embodiments, the light-emitting units in the organic light-emitting device may be two, and the light-emitting units may include a first light-emitting unit and a second light-emitting unit. The two light-emitting units may be the same or different. In an embodiment, the charge generation layer may include a first charge generation layer. The first charge generation layer may be disposed between the first light-emitting unit and the second light-emitting unit, the first light-emitting unit may be disposed between the first electrode and the first charge generation layer, the second light-emitting unit may be disposed between the first charge generation layer and the second electrode, the n-type charge generation layer of the first charge generation layer may include at least one first compound and a metal-containing material, the second light-emitting unit may further include a hole-transporting layer between the light-emitting layer of the second light-emitting unit and the first electrode, and the hole-transporting layer included in the second light-emitting unit may include at least one second compound. In one or more embodiments, in the organic light-emitting device with two light-emitting units, the first light-emitting unit may further include a light-emission assisting layer between the light-emitting layer of the first light-emitting unit and the first electrode, and the hole-transporting layer included in the first light-emitting unit may include at least one second compound. At least one second compound included in the hole-transporting layer of the first light-emitting unit and at least one second compound included in the hole-transporting layer of the second light-emitting unit may be the same as or different from each other.

[0044] A typical organic electroluminescent device includes the following components. Among them, from bottom to top, a substrate, a first electrode, a hole-transporting region, a first light-emitting unit, a first charge generation layer, a second light-emitting unit, an electron-transporting region, and a second electrode are sequentially arranged.

[0045] For convenience, the following will refer to Figure 1 to describe the organic electroluminescent device of the present invention, but this does not mean any limitation to the protection scope of the present invention. It can be understood that all organic electroluminescent devices that can use the hole-transporting material of the present invention are within the protection scope of the present invention.

[0046] In the present invention, the substrate is not particularly limited, and conventional substrates used in organic electroluminescent devices in the prior art can be used, for example, glass, polymer materials, and glass and polymer materials with thin-film transistor (TFT) components, etc.

[0047] In the present invention, the first electrode material is not particularly limited and may be selected from transparent conductive materials such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), etc. known in the prior art, or may be selected from metal materials such as silver and its alloys, aluminum and its alloys, etc., or may be selected from organic conductive materials such as poly(3,4-ethylenedioxythiophene) (PEDOT), or a multilayer structure of the above materials, etc.

[0048] In the present invention, the hole transport region includes a hole injection layer and a hole transport layer. The material of the hole injection layer is not particularly limited and can be made of hole injection layer materials well-known in the art. For example, at least one of the known hole transport materials (HTM) is selected as the hole injection material.

[0049] In the present invention, the hole injection layer may further include a p-type dopant. The type of the p-type dopant is not particularly limited, and various p-type dopants known in the art can be adopted. For example, the p-type dopant may be selected from, but not limited to, at least one of the following compounds p-1 to p-3:

[0050]

[0051] In the present invention, the amount of the p-type dopant is not particularly limited and can be the amount well-known to those skilled in the art.

[0052] In the present invention, the material of the hole transport layer is not particularly limited and can be made of the compounds used in the present invention or can be made of hole transport materials (HTM) well-known in the art. The number of layers of the hole transport layer is not particularly limited and can be adjusted according to actual needs as long as the object of the present invention can be satisfied. For example, 1 layer, 2 layers, 3 layers, 4 layers or more layers.

[0053] For example, the HTM for the hole injection layer material and the HTM for the hole transport layer material may be the same or different and may be selected from, but not limited to, at least one of the following compounds HT-1 to HT-31:

[0054]

[0055]

[0056] In the present invention, the light-emitting layer may include a blue light-emitting layer, a green light-emitting layer or a red light-emitting layer. The light-emitting material in the light-emitting layer is not particularly limited, and various light-emitting materials well-known to those skilled in the art can be used. For example, the material of the light-emitting layer may include a host material and a guest material.

[0057] In the present invention, the host material may be selected from, but not limited to, at least one of the following compounds BH-1 to BH-10:

[0058]

[0059] In the present invention, the guest material is not particularly limited, and at least one of the luminescent layer guest materials known in the art can be used. For example, the luminescent layer guest material may be selected from, but not limited to, at least one of the following compounds BD-1 to BD-9:

[0060]

[0061]

[0062] In the present invention, the amount of the luminescent layer guest material is not particularly limited and can be the amount known to those skilled in the art.

[0063] In the present invention, the electron transport layer in the electron transport region is not particularly limited and can be one of the materials known in the art. The number of layers of the electron transport layer is not particularly limited and can be adjusted according to actual needs as long as the object of the present invention can be satisfied. For example, 1 layer, 2 layers, 3 layers, 4 layers or more layers.

[0064] For example, the known electron transport materials may be selected from, but not limited to, at least one of the following compounds ET-1 to ET-57:

[0065]

[0066]

[0067]

[0068]

[0069] In the present invention, the electron transport layer may further include an n-type dopant. The type of the n-type dopant is not particularly limited, and various n-type dopants known in the art can be used. For example, the following n-type dopants can be used:

[0070]

[0071] In the present invention, the amount of the n-type dopant is not particularly limited and can be the amount known to those skilled in the art.

[0072] In the present invention, the material of the electron injection layer is not particularly limited, and known electron injection materials in the art can be used. For example, it can include but is not limited to at least one of materials such as LiQ, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca, etc. in the prior art.

[0073] In the present invention, the above-mentioned charge generation layer can contain at least one of the charge generation materials of the present invention, or can contain a combination of at least one of the charge generation materials of the present invention and at least one of the following known charge generation materials.

[0074] For example, the known charge generation materials can be selected from but not limited to at least one of the following compounds CGL00R1 to CGL00R4:

[0075]

[0076] In the present invention, the material of the cathode electrode is not particularly limited, and it can be selected from but not limited to metals, metal mixtures, oxides such as magnesium-silver mixture, LiF / Al, ITO, Al, etc.

[0077] The display device provided by the present invention includes the organic electroluminescent device provided by the present invention, and the display device includes but is not limited to displays, televisions, tablet computers, mobile communication terminals, etc.

[0078] The method for preparing the organic electroluminescent device of the present invention is not particularly limited, and any method known in the art can be adopted. For example, the present invention can be prepared by the following preparation method:

[0079] The method for preparing the organic electroluminescent device of the present invention may further include but is not limited to the following steps:

[0080] (1) Clean the reflective anode 22 on the top-emitting organic electroluminescent device substrate 21, and in a cleaning machine, respectively perform steps such as chemical washing, water washing, brushing, high-pressure water washing, air knife, etc., and then perform heat treatment;

[0081] (2) Vacuum deposit a hole injection material on the reflective anode 22 as the first hole injection layer 231;

[0082] (3) Vacuum deposit a hole transport material on the first hole injection layer 231 as the first hole transport layer 241;

[0083] (4) Vacuum deposit a first light-emitting layer 251 on the first hole transport layer 241, and the light-emitting layer contains a host material and a guest material;

[0084] (5) Vacuum deposit an electron transport material on the first light-emitting layer 251 as the first electron transport layer 261;

[0085] (6) A charge generation material is vacuum-evaporated on the first electron transport layer 261 as the charge generation layer 27;

[0086] (7) A hole injection material is vacuum-evaporated on the charge generation layer 27 as the second hole injection layer 232;

[0087] (8) A hole transport material is vacuum-evaporated on the second hole injection layer 232 as the second hole transport layer 242;

[0088] (9) A second light-emitting layer 252 is vacuum-evaporated on the second hole transport layer 242, and the light-emitting layer contains a host material and a guest material;

[0089] (10) An electron transport material is vacuum-evaporated on the second light-emitting layer 252 as the second electron transport layer 262;

[0090] (11) An electron injection material is vacuum-evaporated on the second electron transport layer 262 as the electron injection layer 28;

[0091] (12) A cathode material is vacuum-evaporated on the electron injection layer 28 as the cathode 29.

[0092] The above only describes the structure and preparation method of a typical organic electroluminescent device. It should be understood that the present invention is not limited to this structure. The electron transport material of the present invention can be used in organic electroluminescent devices of any structure, and the organic electroluminescent devices can be prepared by any preparation method known in the art.

[0093] Example 1

[0094] The glass plate coated with the ITO transparent conductive layer is ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in an acetone-ethanol mixed solvent, baked in a clean environment until all moisture is removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam on the surface;

[0095] Then, the glass substrate with the anode is placed in a vacuum chamber, and the vacuum is pumped to less than 10 -5 Torr, and a first hole injection layer is vacuum-evaporated on the above anode layer film. The material of the first hole injection layer includes a hole injection layer material B1 and a p-type dopant p-1, and co-evaporation with multiple sources is used for evaporation. Among them, the evaporation rate of the hole injection layer material B1 is adjusted to 0.1 nm / s, and the evaporation rate of the p-type dopant p-1 is 3% of the evaporation rate of the hole injection layer material B1, and the evaporation film thickness is 10 nm; among them, the structures of B1 and p-1 are as follows:

[0096]

[0097] Then, a hole transport material B1 is vacuum-evaporated as the first hole transport layer on the first hole injection layer, wherein the evaporation rate is 0.1 nm / s and the evaporation film thickness is 80 nm:

[0098] Then, a first light-emitting layer is vacuum-evaporated on the hole transport layer. The first light-emitting layer includes a host material BH-2 and a fluorescent dopant BD-1, and the evaporation is carried out by a multi-source co-evaporation method. Among them, the evaporation rate of the host material BH-2 is adjusted to 0.1 nm / s, the evaporation rate of the fluorescent dopant BD-1 is 3% of the evaporation rate of the host material BH-2, and the evaporation film thickness is 30 nm; the structures of the host material BH-2 and the fluorescent dopant BD-1 are as follows:

[0099]

[0100] Then, a first electron transport layer is vacuum-evaporated on the light-emitting layer. The electron transport material is a compound ET-6, wherein the evaporation rate is 0.1 nm / s and the evaporation film thickness is 30 nm; the structure of the electron transport material ET-6 is as follows:

[0101]

[0102] The above first hole injection layer, first hole transport layer, first light-emitting layer, and first electron transport layer are the first light-emitting unit;

[0103] On the first light-emitting unit, a ratio of the evaporation rates of compound A1 and metal Yb of 99:1 is evaporated for 10 nm as the n-type charge generation layer, and then the hole injection layer material B1 and the p-type dopant p-1 are evaporated in a ratio of 99:1 for 10 nm as the P-type charge generation layer;

[0104] A second light-emitting unit (second hole injection layer, second hole transport layer, second light-emitting layer, second electron transport layer) identical to the first light-emitting unit is evaporated on the charge generation layer;

[0105] Then, LiF with a thickness of 0.5 nm is vacuum-evaporated on the second electron transport layer as the electron injection layer, wherein the evaporation rate is 0.1 nm / s;

[0106] Finally, an Al layer with a thickness of 150 nm is vacuum-evaporated on the electron injection layer as the cathode electrode of the organic electroluminescent device, wherein the evaporation rate is 0.1 nm / s.

[0107] Examples 2-6

[0108] Except that the charge generation layer is replaced by A4, A6, A12, A14, and A20 instead of A1 respectively, the rest are the same as in Example 1.

[0109] Examples 7-10

[0110] Except that the hole transport layer is replaced by B2, B5, B6, and B17 instead of B1 respectively, the rest is the same as in Example 1.

[0111] Comparative Example 1

[0112] Except that the charge generation layer material is selected as CGL00R1 to replace A1 and the hole transport layer is selected as R to replace B1, the rest is the same as in Example 1;

[0113]

[0114] Comparative Example 2

[0115] Except that the charge generation layer material is selected as CGL00R1 to replace A1, the rest is the same as in Example 1; Comparative Example 3

[0116] Except that the hole transport layer material is selected as R to replace B1, the rest is the same as in Example 1;

[0117] The following performance measurements were carried out on the organic electroluminescent devices prepared by the above process:

[0118] At the same brightness, the driving voltage, current efficiency, and device lifetime of the organic electroluminescent devices prepared in Examples 1 - 10 and Comparative Examples 1 - 3 were measured using a digital source meter and a luminance meter. Specifically, the voltage was increased at a rate of 0.1 V per second, and the voltage when the brightness of the organic electroluminescent device reached 1000 cd / m 2 was measured as the driving voltage, and the current density at this time was also measured; the ratio of brightness to current density is the current efficiency; the LT95 lifetime test is as follows: using a luminance meter at 1000 cd / m 2 brightness, keeping a constant current, measuring the time when the brightness of the organic electroluminescent device dropped to 950 cd / m 2 in hours. The results are shown in Table 1.

[0119] Table 1. Performance Results of Organic Electroluminescent Devices

[0120]

[0121] As can be seen from Table 1, for the device structure prepared by the present invention, when using the phenanthroline compounds A1, A4, A6, A12, A14, and A20 of the present invention as charge generation materials for organic electroluminescent devices and using B1, B2, B5, B6, and B17 as hole transport layers for organic electroluminescent devices, the driving voltage can be effectively reduced, the current efficiency can be improved, and the device lifetime can be extended. The materials of the present invention, especially in terms of improving efficiency and extending lifetime, have significant performance improvements and are organic electroluminescent devices with good performance.

[0122] The above are only the preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are all included within the protection scope of the present invention.

Claims

1. A stacked organic light-emitting device, characterized in that, Comprising at least one compound of formula (I) as a charge generation layer material, and further comprising at least one compound of formula (II) as a hole transport layer material, In formula (I), L1 and L2 are selected from chemical bonds, C6-C unsubstituted or substituted by Rc 30 arylene, C3-C unsubstituted or substituted by Rc 30 heteroarylene; X 1 -X 10 is selected from CR or N, R is selected from hydrogen, deuterium, C6-C unsubstituted or substituted by Rc 30 aryl, C3-C unsubstituted or substituted by Rc 30 heteroaryl, and adjacent Rs can be connected to form a ring, and at least one of X1-X 10 is N; the heteroatoms on the heteroaryl or the heteroarylene are each independently selected from O, S or N; In formula (II), R 1 -R 2 are each independently selected from an aryl group having 6 to 30 carbon atoms or a heteroaryl group having 3 to 30 carbon atoms, and at least one is selected from an aryl group or heteroaryl group having 12 - 20 carbon atoms; R 1 , R 2 may be connected to form a ring; R 3 -R 7 are each independently selected from hydrogen, deuterium, a C1-C4 alkane, a C5-C 10 cycloalkane, an aryl group having 6 to 30 carbon atoms, or a heteroaryl group having 3 to 30 carbon atoms, and adjacent substituents may be connected to form a ring; R 8 -R 9 are each independently selected from hydrogen, an aryl group having 6 to 30 carbon atoms, or a heteroaryl group having 3 to 30 carbon atoms, and at least one is not H; the heteroatoms on the heteroaryl group are each independently selected from O, S or N; the hydrogen atoms on the aryl group and heteroaryl group may each independently be replaced by Ra, and the Ra are each independently selected from deuterium, a halogen, a nitro group, a cyano group, an alkyl group having 1 to 4 carbon atoms, a C5-C 20 cycloalkyl group, a phenyl group, a biphenyl group, a terphenyl group or a naphthyl group.

2. The stacked organic electroluminescent device according to claim 1, wherein The compound of formula (I) is selected from the compounds shown as A1 to A30 below:

3. The stacked organic electroluminescent device according to claim 1, wherein, The compound of formula (II) is selected from the compounds shown as B1 to B25 below:

4. The stacked organic electroluminescent device according to claim 1, wherein Including: A first electrode, a second electrode facing the first electrode, m light-emitting units stacked between the first electrode and the second electrode, and m - 1 charge generation layers, where m is an integer equal to or greater than 2; each of the light-emitting units includes at least one light-emitting layer, the charge generation layers are between two adjacent light-emitting units, each of the charge generation layers includes an n-type charge generation layer and a p-type charge generation layer, at least one of the n-type charge generation layers includes at least one compound of formula (I) and a metal-containing material, at least one of the light-emitting units further includes a hole transport layer on its first electrode side, and the hole transport layer includes at least one compound of formula (II).

5. The stacked organic electroluminescent device according to claim 4, wherein The metal-containing material is at least one of a metal, a metal complex, and their combinations.

6. The stacked organic electroluminescent device according to claim 5, wherein The metal-containing material is Li and / or Yb, and the mass ratio of the metal-containing material to the compound of formula (I) in the n-type charge generation layer is 0.5 - 15:85 - 99.

5.

7. The stacked organic electroluminescent device according to claim 4, wherein, The thickness of the charge generation layer is 10 nm - 30 nm, and the thickness of the hole transport layer is 60 nm - 140 nm.

8. A method for preparing a stacked organic electroluminescent device as described in claim 4, characterized in that, Including the following steps: (1) Cleaning the reflective anode on the substrate of the top-emitting organic electroluminescent device, respectively passing through steps such as chemical cleaning, water washing, brushing, high-pressure water washing, air knife in a cleaning machine, and then heat treatment; (2) Vacuum evaporating a hole injection material on the reflective anode as the first hole injection layer; (3) Vacuum evaporating a hole transport material on the first hole injection layer as the first hole transport layer; (4) Vacuum evaporating a first light-emitting layer on the first hole transport layer, and the light-emitting layer contains a host material and a guest material; (5) Vacuum evaporating an electron transport material on the first light-emitting layer as the first electron transport layer; (6) Vacuum evaporating a charge generation material on the first electron transport layer as the charge generation layer; (7) Vacuum evaporating a hole injection material on the charge generation layer as the second hole injection layer; (8) Vacuum evaporating a hole transport material on the second hole injection layer as the second hole transport layer; (9) Vacuum evaporating a second light-emitting layer on the second hole transport layer, and the light-emitting layer contains a host material and a guest material; (10) Vacuum evaporating an electron transport material on the second light-emitting layer as the second electron transport layer; (11) Vacuum evaporating an electron injection material on the second electron transport layer as the electron injection layer; (12) Vacuum evaporating a cathode material on the electron injection layer as the cathode.

9. A display device, characterized in that, Comprising the stacked organic electroluminescent device according to any one of claims 1 to 7.

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