A phosphorescent organic electroluminescent material and its application

Abstract

The present invention belongs to the technical field of electroluminescent devices, and specifically discloses a phosphorescent organic electroluminescent material, and also relates to its application in electroluminescent devices. The phosphorescent organic electroluminescent material provided by the present invention uses a double host material and a specific dopant material as the light-emitting layer material together. The combination of the specific host material and the specific dopant material can obtain a suitable energy level matching, making the concentration of carriers in the light-emitting layer more balanced, thereby improving the comprehensive performance of the organic light-emitting device.

Description

Technical Field

[0001] The present invention relates to the technical field of electroluminescent devices, and specifically discloses a phosphorescent organic electroluminescent material, and also relates to its application in electroluminescent devices. Background Art

[0002] Organic electroluminescence (OLED) refers to the electroluminescent phenomenon of organic materials under the excitation of current or electric field. The device made according to this principle is called an organic electroluminescent device. Compared with the current common flat panel display technologies such as field emission display (FED), liquid crystal display (LCD), and plasma display (PDP), the organic electroluminescent device has the following characteristics: The material uses organic substances / polymers, so the selection range is wide, and any color display from red light to blue light can be realized; the driving voltage is low, the luminous brightness and luminous efficiency are high, and a flexible display device can be made; the response speed is fast and the luminous viewing angle is wide; the device is ultra-thin, small in volume and light in weight; more importantly, the organic light-emitting materials provide a wide range for material selection with their inherent diversity. Through the design, assembly and tailoring of the organic molecular structure, various different needs can be met and large-area display is easy to achieve.

[0003] Generally speaking, inserting one or more ultra-thin organic semiconductor films between the cathode and the anode forms a typical OLED device structure. At present, most small molecule device structures adopt a multi-layer film structure, and each layer has a special function. According to different functions, the organic films can be divided into a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer. The corresponding organic materials are hole injection materials, hole transport materials, electron blocking materials, host materials and doping materials, hole blocking materials, electron transport materials and electron injection materials. When an electric field is applied between the ITO anode with high light transmittance and the metal cathode with high reflectivity, holes will be injected from the anode with a higher work function and electrons will be injected from the cathode with a lower work function into the adjacent organic materials respectively. The injected holes and electrons migrate under the drive of the applied electric field and finally meet and recombine in the light-emitting layer to form excitons. Next, the excitons diffuse in the organic layer and experience a radiative process to emit light.

[0004] As is well known, the light-emitting layer of a phosphorescent OLED device is composed of a host material and a dopant material. The host light-emitting material transfers energy to the guest light-emitting material, and the guest light-emitting material regulates the color to emit light. Therefore, commercially, phosphorescent devices with characteristics such as higher efficiency, more saturated emission spectra, and longer service life are desired. The host material and the dopant material must meet the following conditions: 1. The triplet energy level of the host material should be higher than that of the dopant material; 2. There should be a good overlap between the emission spectrum of the host material and the absorption spectrum of the dopant material; 3. Good thermal stability; 4. The HOMO / LUMO of the host material should be able to encompass the HOMO / LUMO energy levels of the dopant material and match the energy levels of the adjacent functional layer materials; 5. The host material should have a high carrier mobility and good carrier balance. In summary, selecting a suitable combination of host material and dopant material is crucial for obtaining high-performance OLED phosphorescent devices.

[0005] Existing phosphorescent OLED devices generally have drawbacks such as short lifespan and poor luminous efficiency. The present invention intends to propose a novel phosphorescent organic electroluminescent material by studying the light-emitting layer materials to improve the performance of organic electroluminescent devices. Summary of the Invention

[0006] The purpose of the present invention is to develop a phosphorescent organic electroluminescent material that uses a dual-host material and a specific dopant material as the light-emitting layer material together. The combination of the specific host material and the specific dopant material can achieve a suitable energy level matching, making the concentration of carriers in the light-emitting layer more balanced, thereby improving the comprehensive performance of the organic light-emitting device.

[0007] Specifically, in a first aspect, the present invention provides a phosphorescent organic electroluminescent material, comprising: a host material and a dopant material, wherein the host material includes a first host compound and a second host compound;

[0008] The first host compound, the second host compound, and the dopant material respectively have structures represented by general formula (I), general formula (II), and general formula (III):

[0009]

[0010] Wherein:

[0011] In general formula (I), M is selected from a single bond, a phenylene group, or a biphenylene group; Y1 and Y2 are each independently selected from a single bond, a substituted or unsubstituted C6-C ,

[0010] ,

[0009] , ,

[0008] , P2 , ,

[0007] , 30 , , P1 ,

[0011] , 20 , 20 , aryl group; Ar1 and Ar2 are each independently selected from a substituted or unsubstituted C6-C 20 aryl group, a substituted or unsubstituted C2-C 30 heterocyclic group; R P1 、R P2 、RP3 , R P4 , R P5 are each independently selected from hydrogen, deuterium, cyano, substituted or unsubstituted C1-C 10 alkyl, substituted or unsubstituted C6-C 20 aryl, substituted or unsubstituted C2-C 30 heterocyclic group;

[0012] In general formula (II), X is O or S; Z is selected from substituted or unsubstituted C1-C 10 alkyl, substituted or unsubstituted phenyl; r is an integer 0 or 1; L1 and L2 are each independently selected from a single bond, substituted or unsubstituted C6-C 20 aryl; R N1 , R N2 , R N3 , R N4 , R N5 , R N6 , R N7 , R N8 are each independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C 10 alkyl, substituted or unsubstituted C6-C 20 aryl;

[0013] In general formula (III), Y is O, S or Se; T is selected from N and CR; m is an integer 0, 1, 2, 3 or 4; q is an integer 1 or 2; R, R C1 , R C2 , R C3 , R C4 , R C5 are each independently selected from hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C1-C 20 alkyl, substituted or unsubstituted C3-C 20 cycloalkyl, substituted or unsubstituted C1-C 20 heteroalkyl, substituted or unsubstituted C1-C 20 deuterated alkyl, substituted or unsubstituted C6-C 30 aralkyl, substituted or unsubstituted C1-C 20 alkoxy, substituted or unsubstituted C6-C 30 aryloxy, substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted C6-C 30 deuterated aryl, substituted or unsubstituted C3-C 30 heteroaryl, substituted or unsubstituted C1-C 20 alkylsilyl, substituted or unsubstituted C6-C 20 arylsilylalkyl; or, R C1 , R C2 , R C3, R C4 , R C5 In, adjacent substituents can optionally be joined to form a ring;

[0014] In general formula (I), general formula (II) and general formula (III), when the substitutable group has a substituent, the substituent is at least one, and the substituent is selected from deuterium, halogen, cyano, C1-C 30 linear alkyl, C3-C 20 cycloalkyl, C3-C 20 heterocycloalkyl, C1-C 30 alkylsilyl, C6-C 60 aryl, C3-C 60 heteroaryl.

[0015] As a preferred embodiment of the present invention, in general formula (I) representing the first host compound, M is selected from a single bond, phenylene, biphenylene, and is further preferably a single bond; Y1 and Y2 are each independently selected from a single bond, substituted or unsubstituted biphenylene; Ar1 and Ar2 are each independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted diphenyl, substituted or unsubstituted triphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted triphenylene, substituted or unsubstituted carbazolyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted pyridyl; R P1 , R P2 , R P3 , R P4 , R P5 are each independently selected from H, deuterium, substituted or unsubstituted C6-C 12 aryl; the said substitution means that at least one hydrogen on the group is substituted by one or more of deuterium, C1-C4 alkyl, C6-C 18 aryl or C2-C 30 heteroaryl.

[0016] As a more preferred embodiment of the present invention, the first host compound is selected from the following compounds:

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023] As a preferred embodiment of the present invention, the second host compound has the structure shown in general formula (II-1) or general formula (II-2), and is further preferably the structure shown in general formula (II-1):

[0024]

[0025] Among them, the definitions of each substituent in general formula (II-1) and general formula (II-2) are the same as those in the above general formula (II).

[0026] As a more preferred embodiment of the present invention, the second host compound is selected from the following compounds:

[0027]

[0028]

[0029]

[0030]

[0031] As a preferred embodiment of the present invention, the doping material is selected from the following compounds:

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040] As a preferred embodiment of the present invention, the provided phosphorescent organic electroluminescent material, wherein the mixing mass ratio of the host material and the doping material is (80-99):(1-20), and is further preferably (90-99):(1-10). For example, the mass ratio can be 90:10, 91:9, 92:8, 93:7, 94:6, 95:5, 96:4, 97:3, 98:2 or 99:1.

[0041] As a preferred embodiment of the present invention, the mixing mass ratio of the first host compound and the second host compound in the host material is (0.8 to 1.2):(0.8 to 1.2), preferably 1:1.

[0042] In a second aspect, the present invention provides an application of the phosphorescent organic electroluminescent material in an electroluminescent device.

[0043] Preferably, the application of the phosphorescent organic electroluminescent material in an organic layer of an electroluminescent device.

[0044] More preferably, the application of the phosphorescent organic electroluminescent material in a light-emitting layer of an electroluminescent device, used as a light-emitting layer material.

[0045] As a preferred embodiment of the present invention, based on the total mass of the light-emitting layer material, the mass percentage content of the first host compound in the light-emitting layer material is 10% to 90%, the mass percentage content of the second host compound in the light-emitting layer material is 10% to 90%, and the mass percentage content of the doping material in the light-emitting layer material is 1% to 50%;

[0046] More preferably, the mass percentage content of the first host compound in the light-emitting layer material is 20% to 60%, the mass percentage content of the second host compound in the light-emitting layer material is 20% to 60%, and the mass percentage content of the doping material in the light-emitting layer material is 3% to 25%;

[0047] Still more preferably, the mass percentage content of the first host compound in the light-emitting layer material is 40% to 60%, the mass percentage content of the second host compound in the light-emitting layer material is 40% to 60%, and the mass percentage content of the doping material in the light-emitting layer material is 3% to 10%;

[0048] Still more preferably, the mass percentage content of the first host compound in the light-emitting layer material is 45% to 50%, the mass percentage content of the second host compound in the light-emitting layer material is 45% to 50%, and the mass percentage content of the doping material in the light-emitting layer material is 3% to 8%.

[0049] Even more preferably, the mass percentage content of the first host compound in the light-emitting layer material is 46% to 48%, the mass percentage content of the second host compound in the light-emitting layer material is 46% to 48%, and the mass percentage content of the doping material in the light-emitting layer material is 4% to 6%.

[0050] In a third aspect, the present invention provides an electroluminescent device including the phosphorescent organic electroluminescent material.

[0051] Preferably, the electroluminescent device includes an anode, a cathode, and at least one light-emitting layer disposed between the anode and the cathode, and the light-emitting layer includes the phosphorescent organic electroluminescent material.

[0052] More preferably, in the electroluminescent device, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer are disposed between the anode and the cathode, and the light-emitting layer includes the phosphorescent organic electroluminescent material.

[0053] Even more preferably, a packaging layer is further disposed on the cathode of the electroluminescent device.

[0054] In a fourth aspect, the present invention provides a display component including the electroluminescent device.

[0055] The present invention provides a novel phosphorescent organic electroluminescent material. Through the combination of two host materials with specific structures and a dopant material with a specific structure, when used as the light-emitting layer material of an electroluminescent device, a suitable energy level matching of the material can be obtained, and the concentration of carriers in the light-emitting layer can be effectively regulated to reach the desired balance. Compared with the prior art, the phosphorescent organic electroluminescent material of the present invention can significantly improve the performance of the organic electroluminescent device, for example, can improve the voltage, luminous efficiency, and lifespan of the device, etc., making the organic electroluminescent device perform better. Description of the Drawings

[0056] Figure 1 is a schematic diagram of the layer structure of an organic electroluminescent device;

[0057] Figure 2 is a schematic diagram of the layer structure of another organic electroluminescent device. Detailed Description of the Embodiments

[0058] The technical solutions of the present invention will be described in detail below.

[0059] The substrate of the organic electroluminescent device can be glass, metal, plastic, etc. Figure 1 Schematically and non-limitingly shows an organic electroluminescent device 100. It should be noted that the figure is not necessarily drawn to scale, and some layer structures in the figure can also be omitted according to needs. Figure 1The OLED device 100 shown may include a substrate 111, an anode 12, a hole injection layer 13, a hole transport layer 14, an electron blocking layer 15, a light emitting layer 16, a hole blocking layer 17, an electron transport layer 18, an electron injection layer 19, and a cathode 20. The OLED device may be fabricated by sequentially depositing the described layers. The properties and functions of each layer, as well as exemplary materials, are described in more detail in columns 6-10 of U.S. Patent No. 7,279,704B2, the entire content of which is incorporated herein by reference.

[0060] There are more examples for each of the above layers. For example, U.S. Patent No. 5,844,363, which is incorporated herein by reference in its entirety, discloses a flexible and transparent substrate-anode combination. An example of a p-doped hole transporting layer is m-MTDATA doped with F4-TCNQ at a molar ratio of 50:1, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated herein by reference in its entirety. Examples of host materials are disclosed in U.S. Patent No. 6,303,238, which is incorporated herein by reference in its entirety and is awarded to Thompson et al. An example of an n-doped electron transporting layer is BPhen doped with Li at a molar ratio of 1:1, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated herein by reference in its entirety. Examples of cathodes, which include a composite cathode having a thin metal layer such as Mg:Ag and an overlying transparent, conductive, sputter-deposited ITO layer, are disclosed in U.S. Patents Nos. 5,703,436 and 5,707,745, which are incorporated herein by reference in their entirety. The principles and uses of blocking layers are described in more detail in U.S. Patent No. 6,097,147 and U.S. Patent Application Publication No. 2003 / 0230980, which are incorporated herein by reference in their entirety. Examples of injection layers are provided in U.S. Patent Application Publication No. 2004 / 0174116, which is incorporated herein by reference in its entirety. A description of the protective layer can be found in U.S. Patent Application Publication No. 2004 / 0174116, which is incorporated herein by reference in its entirety.

[0061] The above-described layered structure is provided by way of non-limiting examples. The functions of the OLED can be achieved by combining the various functional layers described above, or some layers can be completely omitted. It can also include other layers not explicitly described. Within each layer, a single material or a mixture of multiple materials can be used to achieve optimal performance. Any functional layer can include several sub-layers. For example, the light emitting layer can have two different light emitting materials to achieve a desired emission spectrum. In one embodiment, the OLED can be described as having an "organic layer" disposed between the cathode and the anode. The organic layer can include one or more layers.

[0062] The OLED also requires a packaging layer, such as Figure 2Schematically and non - restrictively shows an organic light - emitting device 210, Figure 2 The shown OLED device 210 may include a substrate 111, an anode 120, a hole injection layer 130, a hole transport layer 140, an electron blocking layer 150, a light - emitting layer 160, a hole blocking layer 170, an electron transport layer 180, an electron injection layer 190, and a cathode 200. Different from Figure 1 this, a encapsulation layer 112 may further be included on the cathode 200 to prevent harmful substances such as moisture and oxygen from the environment. Any material capable of providing an encapsulation function may be used as the encapsulation layer, such as glass or an organic - inorganic hybrid layer. The encapsulation layer should be placed directly or indirectly outside the OLED device. Multilayer thin - film encapsulation is described in U.S. Patent US7968146B2, the entire content of which is incorporated herein by reference.

[0063] Devices prepared according to embodiments of the present invention may be incorporated into a variety of consumer products having one or more electronic component modules (or units) incorporating such devices. For example: viewfinders, microdisplays, 3 - D displays, flat panel displays, monitors, medical monitors, head - up displays, fully or partially transparent displays, flexible displays, vehicle displays, televisions, billboards, lights for indoor or outdoor lighting and / or signaling, smart phones, tablet computers, phablets, wearable devices, smart watches, laptop computers, digital cameras, portable video cameras, taillights, optical sensors, solar cells, lighting elements, organic thin - film transistors, organic field - effect transistors, organic thin - film solar cells, information tags, electronic artificial skin sheets, sheet - type scanners, or electronic papers, etc.

[0064] In this specification, "top" means farthest from the substrate, and "bottom" means closest to the substrate. In the case where the first layer is described as being "disposed" "on" the second layer, the first layer is disposed farther from the substrate. Unless it is specified that the first layer "contacts" the second layer, other layers may exist between the first and second layers. For example, even though there are various organic layers between the cathode and the anode, the cathode may still be described as being "disposed" "on" the anode.

[0065] In this specification, "solution - processable" means capable of being dissolved, dispersed, or transported in a liquid medium in the form of a solution or suspension and / or deposited from a liquid medium.

[0066] When a ligand is believed to directly contribute to the photosensitive properties of an emissive material, the ligand may be called "photosensitive". When a ligand is believed not to contribute to the photosensitive properties of an emissive material, the ligand may be called "auxiliary", but an auxiliary ligand may modify the properties of a photosensitive ligand.

[0067] It is believed that the internal quantum efficiency (IQE) of fluorescent OLEDs can exceed the 25% spin statistics limit through delayed fluorescence. Delayed fluorescence can generally be divided into two types, namely P-type delayed fluorescence and E-type delayed fluorescence. P-type delayed fluorescence is generated by triplet-triplet annihilation (TTA).

[0068] On the other hand, E-type delayed fluorescence does not rely on the collision of two triplets, but rather on the conversion between a triplet and a singlet excited state. Compounds capable of generating E-type delayed fluorescence need to have an extremely small singlet-triplet gap for the conversion between energy states. Thermal energy can activate the transition from the triplet state back to the singlet state. This type of delayed fluorescence is also known as thermally activated delayed fluorescence (TADF). A remarkable feature of TADF is that the delayed component increases with increasing temperature. If the inverse intersystem crossing (IRISC) rate is fast enough to minimize the non-radiative decay of the triplet state, then the fraction of singlet excited states refilled can reach 75%. The total singlet fraction can be 100%, far exceeding the 25% spin statistics of electro-generated excitons.

[0069] The characteristics of E-type delayed fluorescence can be seen in exciplex systems or single compounds. Without being bound by theory, it is believed that E-type delayed fluorescence requires the luminescent material to have a small singlet-triplet energy gap (ΔE S-T ). Organic non-metal-containing donor-acceptor luminescent materials may be able to achieve this. The emission of these materials is usually characterized as donor-acceptor charge transfer (CT)-type emission. The spatial separation of the HOMO and LUMO in these donor-acceptor type compounds usually results in a small ΔE S-T . These states can include CT states. Generally, donor-acceptor luminescent materials are constructed by connecting an electron donor moiety (such as an amino or carbazole derivative) to an electron acceptor moiety (such as an N-containing six-membered aromatic ring).

[0070] The C6~C 60 aryl, C3~C 60A heteroaryl group, unless otherwise specified, is an aromatic group that satisfies a π-conjugated system, including both monocyclic and polycyclic cases. A monocyclic group refers to a molecule containing at least one phenyl group. When the molecule contains at least two phenyl groups, the phenyl groups are independent of each other and are connected by single bonds. Exemplarily, such as phenyl, biphenyl, terphenyl, etc.; a polycyclic group refers to a molecule containing at least two benzene rings, but the benzene rings are not independent of each other, but are fused to each other by sharing ring edges. Exemplarily, such as naphthyl, anthryl, phenanthryl, etc.; a monocyclic heteroaryl group refers to a molecule containing at least one heteroaryl group. When the molecule contains a heteroaryl group and other groups (such as aryl, heteroaryl, alkyl, etc.), the heteroaryl group and other groups are independent of each other and are connected by single bonds. Exemplarily, such as pyridine, furan, thiophene, etc.; a polycyclic heteroaryl group refers to a group fused by at least one phenyl group and at least one heteroaryl group, or, fused by at least two heteroaryl groups. Exemplarily, such as quinoline, isoquinoline, benzofuran, dibenzofuran, benzothiophene, dibenzothiophene, etc.

[0071] In this specification, a substituted or unsubstituted C6-C 60 The aryl group is preferably C6-C 30 The aryl group, exemplary preferably is an aryl group selected from the group consisting of phenyl, naphthyl, anthryl, benzanthryl, phenanthryl, benzophenanthryl, pyrenyl, chrysenyl, perylenyl, fluoranthenyl, tetraphenyl, pentaphenyl, benzopyrenyl, biphenyl, azobenzene, terphenyl, triphenylphenyl, tetraphenyl, fluorene, spirobifluorene, dihydrophenanthryl, dihydropyrenyl, tetrahydropyrenyl, cis- or trans-indeno[1,2-b]fluorene, truxene, isotruxene, spirotruxene, spiroisotruxene. The C6-C 60 The aryl group of the present invention can also be a group formed by combining the above groups by single bond connection or / and fusion.

[0072] In this specification, the heterocyclic group includes aryl and non-aromatic cyclic groups. Isoaryl also refers to heteroaryl. Preferred non-aromatic heterocyclic groups are those containing 3 to 7 ring atoms, which include at least one heteroatom such as nitrogen, oxygen, and sulfur. The heterocyclic group can also be an aromatic heterocyclic group having at least one heteroatom selected from nitrogen atom, oxygen atom, sulfur atom, and selenium atom.

[0073] In this specification, a substituted or unsubstituted C3-C 60 The heteroaryl group is preferably C3-C 30 The heteroaryl group can be a nitrogen-containing heteroaryl group, an oxygen-containing heteroaryl group, a sulfur-containing heteroaryl group, etc. As a preferred example of the heterocycle in the present invention, for example, furyl, thienyl, pyrrolyl, benzofuryl, benzothienyl, isobenzofuryl, indolyl, dibenzofuryl, dibenzothienyl, carbazolyl and its derivatives, wherein, the carbazolyl derivative is preferably 9-phenylcarbazole, 9-naphthylcarbazole benzocarbazole, dibenzocarbazole or indolocarbazole. The C3-C 60The heteroaryl group may also be a group formed by combining the above groups through single bonds or / and fusion.

[0074] In this specification, unless otherwise specified, alkyl includes linear alkyl, branched alkyl, and also includes the concept of cycloalkyl. Examples include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, adamantyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, pentafluoroethyl, 2,2,2-trifluoroethyl, etc.

[0075] In this specification, cycloalkyl includes monocyclic cycloalkyl and polycyclic cycloalkyl. Examples include: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, etc.

[0076] In this specification, as C1-C 20 Examples of alkoxy groups include: methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy, pentyloxy, isopentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, etc. Among them, methoxy, ethoxy, n-propoxy, isopropoxy, tert-butoxy, sec-butoxy, isobutoxy, and isopentyloxy are preferred, and methoxy is more preferred.

[0077] In this specification, as the aryloxy group of C6-C 60 Examples include the groups formed by connecting each of the groups exemplified above for the substituted or unsubstituted C6-C 60 aryl group to oxygen. Specific examples can refer to the above examples and will not be elaborated here.

[0078] In this specification, examples of halogen include: fluorine, chlorine, bromine, iodine, etc.

[0079] The materials for specific layers in the organic light-emitting devices described in the present invention can be used in combination with various other materials present in the devices. These materials are described in detail in US Patent Application US20190363261A1 and Patent Application 202210423809.X. The materials described herein as being usable for specific layers in organic light-emitting devices can be used in combination with a variety of other materials present in the devices. For example, the light-emitting layer materials disclosed herein can be used in combination with a variety of transport layers, blocking layers, injection layers, electrodes, and other layers that may be present. These materials are described in detail in both US Patent Application US20190363261A1 and Patent Application 202210423809.X, the entire contents of which are incorporated herein by reference. The materials described or mentioned therein are non-limiting examples of materials that can be used in combination with the materials disclosed herein, and those skilled in the art can easily consult the literature to identify other materials that can be used in combination.

[0080] The preparation method of the organic electroluminescent device is not limited. The preparation methods in the following examples are only examples and should not be construed as limitations. Those skilled in the art can reasonably improve the preparation methods in the following examples based on the prior art. Exemplarily, the ratios of various materials in the light-emitting layer are not particularly limited, and those skilled in the art can reasonably select within a certain range according to the prior art. For example, based on the total weight of the light-emitting layer materials, the first host compound accounts for 10%-90%, the second host compound accounts for 10%-90%, and the dopant compound accounts for 1%-50%. Preferably, the dopant compound accounts for 3%-25%. More preferably, the first host compound accounts for 20%-60%, the second host compound accounts for 20%-60%, and the dopant compound accounts for 3%-25%. The light-emitting devices were prepared using conventional equipment in the art and tested by methods well-known to those skilled in the art. Since those skilled in the art are aware of the relevant content such as the use of the above equipment and testing methods and can obtain the inherent data of the samples determinately and without being affected, the above content will not be elaborated further in this patent.

[0081] The technical solutions of the present invention will be further described below through specific examples. The following examples are only used to illustrate the present invention, but not to limit the scope of the present invention. All equivalent changes or modifications made without departing from the spirit disclosed by the present invention should be included within the scope of the claims.

[0082] The preparation methods of the first host compound, the second host compound, and the doping material selected in the present invention are not limited. Typically but not restrictively, the following compounds are taken as examples, and their synthetic routes and preparation methods are as follows.

[0083] Synthesis of P-18

[0084]

[0085] Add 0.8 L of toluene, 0.2 L of ethanol, 0.1 L of water, 28.7 g (0.1 mol) of raw material P-18-1, and 24.6 g (0.1 mol) of 3-bromocarbazole into a 2 L three-necked flask with mechanical stirring. Start stirring, replace the air with nitrogen three times, then add 1.1 g of tetrakis(triphenylphosphine)palladium and 27.6 g (0.2 mol) of potassium carbonate. Heat to reflux for 8 h, and then cool to room temperature after the reaction is completed. The reaction solution is extracted and separated, and the organic phase is dried by rotary evaporation and passed through a silica gel column (heptane:ethyl acetate = 1:1) to obtain 30.7 g of solid P-18-2.

[0086] 4.1 g (0.01 mol) of the intermediate P-18-2 from the previous step was added to a 250 mL three-necked flask. Then, 100 mL of toluene, 2.5 g (0.01 mol) of 1-bromodibenzofuran, and 1.92 g (0.02 mol) of sodium tert-butoxide were added. After nitrogen displacement three times, 90 mg of Pd2(dba)3 and 0.1 mL of tri-tert-butylphosphine were added. Magnetic stirring was initiated and the mixture was heated to reflux for 5 h. After completion of the reaction, the mixture was cooled to room temperature. The reaction solution was extracted and separated, and the organic phase was dried over a silica gel column (heptane:ethyl acetate = 3:1) to obtain 3.6 g of solid P-18.

[0087] Elemental analysis (C 42 H 26 N2O): theoretical value C, 87.78; H, 4.56; N, 4.87; found value C, 87.57; H, 4.78; N, 5.09. MS (m / e): 574.

[0088] Synthesis of N-3

[0089]

[0090] To a mechanically stirred 2L three-necked flask, 30.2g (0.1mol) of N-3-1, 1L of toluene, 16.7g (0.1mol) of carbazole, and 19.2g (0.2mol) of sodium tert-butoxide were added. After nitrogen replacement three times, 1g of Pd2(dba)3 and 1mL of tri-tert-butylphosphine were added. Stirring was initiated and the mixture was heated to reflux for 8h. After completion of the reaction, the mixture was cooled to room temperature. The reaction solution was extracted and separated, and the organic phase was dried by passing through a silica gel column (heptane:ethyl acetate = 5:1) to obtain 26g of N-3-2 as a solid.

[0091] 4.3 g (0.01 mol) of the intermediate N-3-2 from the previous step was added to a 250 mL three-necked flask. 100 mL of toluene, 20 mL of ethanol, 10 mL of water, and 2.88 g (0.01 mol) of furanboric acid were then added. After nitrogen replacement three times, 100 mg of tetrakis(triphenylphosphine)palladium and 2.76 g (0.02 mol) of potassium carbonate were added. Magnetic stirring was initiated and the mixture was heated to reflux for 12 h. After completion of the reaction, the mixture was cooled to room temperature. The reaction solution was extracted and separated, and the organic phase was dried over a silica gel column (heptane:ethyl acetate = 3:1) to obtain 4.7 g of solid N-3.

[0092] Elemental analysis (C 45 H 28 N4O): theoretical value C, 84.35; H, 4.40; N, 8.74; O, 2.50; found value C, 84.56; H, 4.60; N, 8.62. MS (m / e): 640.

[0093] Synthesis of ligand M1

[0094]

[0095] The synthesis route is as follows:

[0096]

[0097] The specific synthesis preparation method is as follows:

[0098] (1) Synthesis of compound M1-1

[0099] In a 1 L three-necked flask equipped with a mechanical stirrer, a reflux condenser and a nitrogen protection device, 2-bromo-5-methylpyridine (17.2 g, 0.1 mol), phenylboronic acid (12.2 g, 0.1 mol), potassium carbonate (27 g, 0.2 mol), tetrakis(triphenylphosphine)palladium 1.1 g, 400 mL of tetrahydrofuran and 100 mL of water were successively added, and the mixture was heated to reflux for 12 hours. After the reaction was completed, the organic phase was separated, extracted, dried, purified by column chromatography, and the solvent was evaporated to obtain 13.7 g of product M1-1.

[0100] (2) Synthesis of compound M1-2

[0101] In a 1 L three-necked flask equipped with a mechanical stirrer, a reflux condenser and a nitrogen protection device, M1-1 (16.9 g, 0.1 mol), iridium(III) chloride hydrate (8.8 g, 0.25 mol), ethylene glycol monoethyl ether 450 mL and distilled water 150 mL were successively added. The mixture was heated to 130 °C and refluxed for 24 hours. After natural cooling, 100 mL of distilled water was added, and the mixture was shaken, filtered by suction, washed with water and then with ethanol. It was dried under vacuum to obtain 23.4 g of yellow solid product M1-2.

[0102] (3) Synthesis of compound M1

[0103] In a 1 L three-necked flask equipped with a nitrogen protection device, M1-2 (112.8 g, 0.1 mol) and 300 ml of dichloromethane were successively added and stirred well. Then, a 300 ml methanol solution containing silver trifluoromethanesulfonate (51.2 g, 0.2 mol) was added, and the mixture was stirred at room temperature for 24 hours. It was filtered through diatomaceous earth, and the filtrate was evaporated to dryness to obtain 49.0 g of khaki solid M1.

[0104] Synthesis of ligand H1

[0105]

[0106] The synthesis route is:

[0107]

[0108] The specific preparation method is as follows:

[0109] (1) Synthesis of Compound H1-1

[0110] In a 2 L three-necked flask equipped with mechanical stirring, add 2,6-dibromophenol (25.2 g, 0.1 mol), 3-chloro-2-fluorobenzeneboronic acid (17.4 g, 0.1 mol), 500 mL of toluene, 300 mL of ethanol, 300 mL of water, and potassium carbonate (27.6 g, 0.2 mol). Start stirring, and under nitrogen, add tetrakis(triphenylphosphine)palladium (1.15 g, 0.001 mol). Reflux the reaction for 24 h. After the reaction is completed, separate the organic phase, extract, dry, perform column chromatography, and rotary evaporate the solvent to obtain 19.5 g of solid H1-1.

[0111] (2) Synthesis of Compound H1-2

[0112] In a 1 L three-necked flask equipped with mechanical stirring, add H1-1 (30 g, 0.1 mol) and potassium carbonate (11.6 g, 0.1 mol). Add 200 mL of DMF and react at 120 °C for 5 h. After the reaction is completed, separate the organic phase, extract, dry, perform column chromatography, and rotary evaporate the solvent to obtain 22.5 g of solid H1-2.

[0113] (3) Synthesis of Compound H1-3

[0114] In a 1 L three-necked flask equipped with mechanical stirring, add H1-2 (28.2 g, 0.1 mol), bis(pinacolato)diboron (25.4 g, 0.1 mol), palladium(II) dichloride - DPPF complex (0.7 g, 0.001 mol), potassium acetate (19.6 g, 0.2 mol), and 300 mL of DMF. React at 90 °C for 10 h under nitrogen protection. After the reaction is completed, separate the organic phase, extract, dry, perform column chromatography, and rotary evaporate the solvent to obtain 22.3 g of solid H1-3.

[0115] (4) Synthesis of Compound H1-4

[0116] In a 1 L three-necked flask equipped with mechanical stirring, add H1-3 (32.8 g, 0.1 mol), 2-bromopyridine (15.8 g, 0.1 mol), potassium acetate (19.6 g, 0.2 mol), palladium(II) dichloride - DPPF complex (0.7 g, 0.001 mol), 400 mL of tetrahydrofuran, and 100 mL of water. Heat to reflux and react for 12 h. Cool to room temperature, add water, extract with ethyl acetate, wash the separated organic layer with brine, separate the organic phase, extract, dry, perform column chromatography, and rotary evaporate the solvent to obtain 21.7 g of solid H1-4.

[0117] (5) Synthesis of Compound H1

[0118] In a 1 L three-necked flask equipped with mechanical stirring, add H1-4 (27.9 g, 0.1 mol), 2-cyanobenzeneboronic acid (14.7 g, 0.1 mol), 500 mL of toluene, and 100 mL of water. React under reflux for 12 hours. After the reaction is completed, separate the organic phase, extract, and rotary evaporate the solvent to obtain 25 g of solid H1.

[0119] Elemental analysis (C 24 H 14 N2O): Theoretical values: C, 83.22; H, 4.07; N, 8.09; O, 4.62; Measured values: C, 83.19; H, 4.08; N, 8.11. MS (m / e): 346.

[0120] Synthesis of Compound I-7

[0121]

[0122] The synthesis route is as follows:

[0123]

[0124] In a 500 mL three-necked flask equipped with mechanical stirring, reflux condenser, and nitrogen protection device, sequentially add M1 (7.42 g, 0.01 mol) and H1 (3.46 g, 0.01 mol), then add 200 ml of ethanol. Heat this mixture under reflux for 24 hours. Cool the reactant to room temperature, filter the resulting yellow solid, dissolve this solid in dichloromethane, and separate by column chromatography to obtain 4.54 g of bright yellow solid Compound I-7.

[0125] Elemental analysis (C 48 H 33 IrN4O): Theoretical values: C, 65.96; H, 3.81; Ir, 21.99; N, 6.41; O, 1.83; Measured values: C, 65.82, H, 3.64, N, 6.59. MS (m / e): 874.

[0126] Referring to the synthesis method of the above Compound 1-7, Compound I-194 was synthesized:

[0127]

[0128] The specific synthesis method can also refer to Patent Application 202210423809.X.

[0129] Device Example

[0130] Preparation steps of Device Example 1-1: First, clean an indium tin oxide (ITO) glass substrate with a thickness of 100 nm, and then treat it with UV ozone and oxygen plasma. After treatment, dry the substrate in a glove box filled with nitrogen to remove moisture, and then mount the substrate on a substrate holder and load it into a vacuum chamber. The following formulated organic layers are vapor-deposited on the ITO anode once by thermal vacuum at a rate of - 7 under the condition of about 5×10 torr, as follows:

[0131] Compound HT-1 and Compound HI are co-deposited as the hole injection layer (HIL), with a total thickness of Compound HI accounts for 3% of the total weight of the hole injection layer;

[0132] Compound HT-1 is used as the hole transport layer (HTL), with a thickness of

[0133] Compound HT-2 is used as the electron blocking layer (EBL), with a thickness of

[0134] Then, Compound I-7 is doped and co-deposited in the first host compound P-18 and the second host compound N-3 as the emitting layer (EML), with a total thickness of The weight ratio of Compound P-18 to the second host compound N-3 is 1:1, and the dopant Compound I-7 accounts for 6% of the total weight of the emitting layer;

[0135] Compound ET-1 is used as the hole blocking layer (HBL), with a thickness of

[0136] On the HBL, Compound ET-2 and lithium 8-hydroxyquinoline (Liq) are co-deposited as the electron transport layer (ETL), where Liq accounts for 50% of the total weight of the ETL layer, and the total thickness of the ETL layer is

[0137] Finally, vapor-deposit thickness of Liq as the electron injection layer (EIL), and vapor-deposit 150 nm of aluminum as the cathode. Then transfer the device back to the glove box and encapsulate it with a glass cover plate to complete the device.

[0138] Device Comparative Examples 1-1 to 1-3: The difference from the preparation method of Device Example 1-1 is only that the emitting layer host materials of Comparative Examples 1-1 to 1-3 shown in Table 1 are used, and the weight ratio of the host material to the dopant material is adjusted to 90:10. When using a single host material, the performance of the device obtained under this ratio is better than that under other ratios.

[0139] Device Comparative Examples 1-4 to 1-6: The only difference from the manufacturing method of Device Example 1-1 is that the host materials of Comparative Examples 1-4 to 1-6 in Table 1 are used.

[0140] The detailed device layer partial structures and thicknesses of the device examples and comparative examples provided above are shown in Table 1. For the layers with more than one material used, different compounds are doped in the recorded weight ratios.

[0141] Table 1

[0142]

[0143] The structures of some of the materials used in the above devices are as follows:

[0144]

[0145]

[0146] The performances of the devices of the above examples and comparative examples were detected, and Table 2 lists the test results of Example 1-1 and Comparative Examples 1-1 to 1-6. In Table 2, the voltage, external quantum efficiency, color coordinates, peak wavelength, and full width at half maximum were measured at a current density of 20 mA / cm 2 and the lifetime is the time required for the initial emission luminance of 20000 nit to decay to 95% of the initial luminance.

[0147] Table 2 Device Performance Detection Data

[0148]

[0149] Table 2 shows the test results of the electroluminescent devices made with different host materials mixed with dopant I-7 as the light-emitting layer. It can be seen from Table 2 that the color coordinates of Device Example 1-1 are (0.35, 0.62), the peak wavelength is 530 nm, the full width at half maximum is 60.4 nm, and at 20 mA / cm 2The voltage under [conditions] is 3.88 V, the external quantum efficiency is 20.86%, the current efficiency is 76 cd / A, and the T95 lifetime is 764 h at 20000 nit. All the performance parameters of Device Comparative Example 1-1 are inferior to those of Device Example 1-1. The spectrum redshifts, especially the T95 lifetime is only 42 h, far inferior to the lifetime of Example 1-1. Although the full width at half maximum of Comparative Example 1-2 is only 59.1 nm, slightly narrower than that of Example 1-1, and the voltage is the same as that of Example 1-1, its external quantum efficiency, current efficiency, and T95 lifetime are all inferior to those of Example 1-1. Although the voltage of Comparative Example 1-3 is only 3.87 V, the spectrum redshifts compared with that of Example 1-1, and its external quantum efficiency, current efficiency, and T95 lifetime are all inferior to those of Example 1-1. The peak wavelength and full width at half maximum of Comparative Example 1-4 are close to those of Example 1-1, but the voltage is as high as 4.95 V, more than 1 V higher than that of Example 1-1, and its external quantum efficiency, current efficiency, and T95 lifetime are all inferior to those of Example 1-1. The spectrum of Comparative Example 1-5 redshifts slightly compared with that of Example 1-1, the full width at half maximum is slightly narrower at 58.7 nm, and the three parameters of voltage, external quantum efficiency, and current efficiency are all inferior to those of Example 1-1, and the lifetime is also significantly lower than that of Example 1-1, with a difference of 219 h. The parameters of voltage, external quantum efficiency, current efficiency, full width at half maximum, peak value, and lifetime of Comparative Example 1-6 are all inferior to those of Example 1-1. The above comparison results show that using the combination of light-emitting layer materials disclosed in the present invention can improve the spectrum and significantly improve the comprehensive performance of the device, such as reducing the voltage, increasing the efficiency and lifetime.

[0150] The following prepared Device Example 2-1 and Device Comparative Examples.

[0151] For Device Example 2-1, the difference in its preparation steps from those of Device Example 1-1 is only that the dopant compound used in the light-emitting layer is dopant compound I-194, and it accounts for 4% of the total weight of the light-emitting layer.

[0152] Device Comparative Examples 2-1 to 2-3: The difference from Device Example 2-1 is only that the light-emitting layer host materials in Comparative Examples 2-1 to 2-3 in Table 3 are used, and the weight ratio of the host material to the dopant is adjusted to 92:8. When using a single host material, the performance of the device obtained under this ratio is better than that under other ratios.

[0153] Device Comparative Examples 2-4 to 2-6: The difference from Device Example 2-1 is only that the light-emitting layer host materials in Comparative Examples 2-4 to 2-6 in Table 3 are used.

[0154] The detailed device layer partial structures and thicknesses of the above-provided device examples and comparative examples are shown in Table 3. For the layers with more than one material used, they are doped with different compounds in the recorded weight ratios.

[0155] Table 3

[0156]

[0157] In Table 3, the structures of the compounds HI, HT-1, HT-2, GH-1, GH-2, GH-3, ET-1, and ET-2 used in each device are the same as those in Table 1.

[0158] The performances of the devices in the above examples and comparative examples were also detected. Table 4 lists the test results of Example 2-1 and Comparative Examples 2-1 to 2-6. In Table 4, the voltage, external quantum efficiency, color coordinates, peak wavelength, and full width at half maximum were measured at a current density of 20 mA / cm 2 and the lifetime is the time required for the initial luminous brightness of 20000 nit to decay to 95% of the initial brightness.

[0159] Table 4 Device Performance Detection Data

[0160]

[0161] Table 4 shows the test results of electroluminescent devices fabricated with different host materials mixed with dopant I-194 as the light-emitting layer. The color coordinates of Device Example 2-1 are (0.34, 0.63), the peak wavelength is 529 nm, the full width at half maximum is 59.8 nm, and 20 mA / cm 2The voltage under [conditions] is 3.75 V, the external quantum efficiency is as high as 21.21%, the current efficiency is 81 cd / A, and the T95 life at 20000 nit is 793 h. The spectrum of Comparative Example 2-1 of the device has a slight red shift, and the full width at half maximum is close to that of Example 2-1 of the device, but the voltage is as high as 4.93 V, more than 1 V higher than that of Example 2-1 of the device. At the same time, the external quantum efficiency, current efficiency, and T95 life are all inferior to those of Example 2-1. The spectrum of Comparative Example 2-2 has a red shift and the full width at half maximum is slightly narrower, but the voltage is 4.08 V, 0.33 V higher than that of Example 2-1 of the device, and the external quantum efficiency, current efficiency, and T95 life are all inferior to those of Example 2-1. The color coordinates of Comparative Example 2-3 are (0.37, 0.60), and the spectrum has an obvious red shift compared with Example 2-1. Although the voltage is close to that of Example 2-1, the external quantum efficiency, current efficiency, and T95 life are all inferior to those of Example 2-1. The spectrum of Comparative Example 2-4 has a slight red shift and the full width at half maximum is slightly narrower, and other parameters are all inferior to those of Example 2-1. In particular, the voltage is as high as 4.95 V, 1.2 V higher than that of Example 2-1. The spectrum of Comparative Example 2-5 has a slight red shift and the full width at half maximum is slightly narrower. The external quantum efficiency is as high as 20.86%, the current efficiency is 80 cd / A, slightly lower than that of Example 2-1, and the T95 life is 614 h, 151 h less than that of Example 2-1. The voltage, spectrum, full width at half maximum, external quantum efficiency, and current efficiency of Comparative Example 2-6 are all similar to those of the example, and the T95 life is 765 h, 28 h less than that of Example 2-1, and the performance is worse than that of Example 2-1 of the device.

[0162] The above results show that for the phosphorescent dopant material with a specific structure adopted in the present invention, when using a light-emitting layer composed of a conventional host material, compared with the combination of host materials provided by the present invention, the electroluminescent device including the combination of the host material and dopant material disclosed in the present invention has more excellent comprehensive performance, and can significantly improve the comprehensive performance of the organic electroluminescent device, such as voltage, luminous efficiency, spectrum, and life.

[0163] It should be understood that the various embodiments described herein are only examples and are not intended to limit the scope of the present invention. Therefore, as will be obvious to those skilled in the art, the claimed invention may include variations of the specific and preferred embodiments described herein. Many of the materials and structures described herein may be replaced by other materials and structures without departing from the spirit of the present invention. It should be understood that the various theories regarding why the present invention works are not intended to be restrictive.

Claims

1. A phosphorescent organic electroluminescent material, characterized in that, Comprising: A host material and a doping material, wherein the host material comprises a first host compound and a second host compound; The first host compound and the second host compound respectively have the structures shown in Formula (I) and Formula (II): The mixing mass ratio of the host material and the doping material is (90 - 99):(1 - 10); The mixing mass ratio of the first host compound and the second host compound in the host material is 1:1; The doping material is selected from the following compounds:

2. The application of the phosphorescent organic electroluminescent material according to claim 1 in the light-emitting layer of an electroluminescent device.

3. The application according to claim 2, characterized in that The mass percentage content of the doping material in the light-emitting layer material is 3% - 10%.

4. The application according to claim 2, characterized in that, The electroluminescent device comprises an anode, a cathode, and at least one light-emitting layer disposed between the anode and the cathode, and the light-emitting layer comprises the phosphorescent organic electroluminescent material according to claim 1.

5. The application according to claim 4, wherein A hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer are disposed between the anode and the cathode, and the light-emitting layer comprises the phosphorescent organic electroluminescent material according to claim 1.

6. The application according to claim 5, characterized in that, A packaging layer is further disposed on the cathode.

7. A display component, characterized in that, Comprising an electroluminescent device, and the electroluminescent device comprises the phosphorescent organic electroluminescent material according to claim 1.

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