A blue light organic electroluminescent device and a display device containing the same

Abstract

The present invention discloses a blue light organic electroluminescent device and a display device comprising the same. The blue light organic electroluminescent device comprises a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer and an electron transport layer arranged in sequence, wherein the light emitting layer comprises at least a first host and a second host; wherein the first host and the second host are homologues of anthracene or isomers of anthracene. The present invention can at least partially solve the problems of low luminous efficiency, short life and low yield of OLED blue light devices in the prior art.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and more specifically to a blue light organic electroluminescent device and a display device comprising the same. Background Art

[0002] Among the mass-produced OLED devices today, the red and green light devices are phosphorescent devices, and the luminescent bodies are both dual-host materials. However, due to the lagging development of technology and process for blue phosphorescent materials, the mass-produced blue light devices are fluorescent devices, and the blue light host material is a single host material. Through photoexcitation or electroexcitation, 25% of singlet excitons and 75% of triplet excitons can be formed. Since the energy level difference ΔEst between S1 and T1 of the anthracene host is large, only 25% of the singlet excitons can be utilized. The low utilization rate of excitons leads to low device efficiency, which is far behind the efficiency of phosphorescent devices.

[0003] In addition, the mass-produced blue phosphorescent materials also have the problem of crucible clogging, which further reduces their yield. Summary of the invention

[0004] In view of the defects in the prior art, the present invention provides a blue light organic electroluminescent device and a display device comprising the blue light organic electroluminescent device, which can at least partially solve the problems of low luminous efficiency, short life and low yield of OLED blue light devices in the prior art.

[0005] In a first aspect, the present invention provides a blue light organic electroluminescent device, comprising a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer and an electron transport layer arranged in sequence, wherein the light-emitting layer comprises at least a first host and a second host; wherein the first host and the second host are homologues of anthracene or isomers of anthracene to each other.

[0006] Optionally, the wavelengths of the photoluminescence spectra of the first body and the second body are between 380 nm and 470 nm, and the absolute value of the difference in the wavelengths of the photoluminescence spectra of the first body and the second body is less than 10 nm.

[0007] Optionally, the mass ratio of the first body to the second body is 1:99 to 99:1.

[0008] Optionally, the anthracene homologue or anthracene isomer is selected from one of the compounds represented by the following structural formulas:

[0009]

[0010] Optionally, at least three of the hole transport layer, the electron blocking layer, the hole blocking layer and the electron transport layer contain a spirobifluorene derivative.

[0011] Optionally, when the hole transport layer contains the spirobifluorene derivative, the energy level difference between the hole transport layer and the adjacent layer |▽HOMO|≤0.3 eV; and / or

[0012] When the electron transport layer includes the spirobifluorene derivative, the energy level difference between the electron transport layer and an adjacent layer |▽LUMO|≤0.3 eV.

[0013] Optionally, the glass transition temperature of the spirobifluorene derivative is greater than 120°C.

[0014] Optionally, the spirobifluorene derivatives in each layer are independently selected from one of the compounds represented by the following structural formula I:

[0015]

[0016] in:

[0017] R 1 , R 2 , R 3 and R 4 are each independently selected from aryl or heteroaryl, and the adjacent R 1 , R 2 , R 3 and R 4 Can bond to form a ring;

[0018] a, b, c and d are each independently selected from integers of 0-4.

[0019] Optionally, the spirobifluorene derivative shown in structural formula I that forms the hole transport layer contains an electron donating group, and the electron donating group is selected from one or more of a substituted or unsubstituted aromatic amine group, a substituted or unsubstituted carbazole group, and a substituted or unsubstituted fluorene group.

[0020] Optionally, the spirobifluorene derivative shown in structural formula I that forms the electron transport layer contains an electron withdrawing group, and the electron withdrawing group is selected from one or more of a substituted or unsubstituted azine group, a substituted or unsubstituted phenanthroline group, a substituted or unsubstituted phosphino group, and a substituted or unsubstituted cyano group.

[0021] In a second aspect, the present invention provides a display device, comprising any one of the above-mentioned blue organic electroluminescent devices.

[0022] The beneficial effects of the present invention are as follows:

[0023] In the blue light organic electroluminescent device provided by the present invention, the light-emitting layer includes at least a first main body and a second main body; and the first main body and the second main body are homologues of anthracene or isomers of anthracene. Among them, the structures of the homologues of anthracene or isomers of anthracene are similar, so that it can be ensured that no exciplex is formed between the two molecules to cause the spectrum to red shift, and the phenomenon of material crystallization can be well improved on the basis of maintaining the original properties of the material, thereby solving the problem of mass production material crucible plugging; at the same time, the two homologues of anthracene or isomers of anthracene with similar structures can directly obtain carriers from the adjacent functional layer, and no energy transfer is required between each other, so there is no phenomenon of carrier traps formed due to changes in the concentration ratio, thereby causing the device to not emit light; in addition, a good amorphous film can be formed, thereby enhancing the performance of the device and facilitating the improvement of the device's life. In some preferred examples, in the blue light organic electroluminescent device provided by the present invention, at least three layer structures adjacent to the light-emitting layer contain spirobifluorene derivatives to further improve the crystallinity, luminous efficiency and other issues of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0025] Figure 1 The spectra of the single component BH-4 isomer of anthracene and the isomeric system in the examples of the present invention are shown.

[0026] Figure 2 A schematic diagram showing the combination of an HTL layer, an EBL layer, an HBL layer and an ETL layer in an organic electroluminescent device according to an embodiment of the present invention is shown.

[0027] Figure 3 A schematic diagram showing the combination of an HTL layer, an EBL layer, an HBL layer and an ETL layer in another organic electroluminescent device according to an embodiment of the present invention is shown.

[0028] Figure 4 A schematic diagram showing the combination of an HTL layer, an EBL layer, an HBL layer and an ETL layer in another organic electroluminescent device according to an embodiment of the present invention is shown.

[0029] Figure 5 A schematic diagram showing the combination of an HTL layer, an EBL layer, an HBL layer and an ETL layer in another organic electroluminescent device according to an embodiment of the present invention is shown.

[0030] Figure 6 A schematic diagram showing the combination of an HTL layer, an EBL layer, an HBL layer and an ETL layer in another organic electroluminescent device according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0031] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0032] The embodiments of the present invention provide a blue light organic electroluminescent device and a display device including the blue light organic electroluminescent device to solve the problems of low efficiency, short life and easy crucible clogging of materials in existing OLED blue light devices.

[0033] An embodiment of the present invention provides a blue light organic electroluminescent device, which includes a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer and an electron transport layer arranged in sequence, wherein the light-emitting layer includes at least a first host and a second host; wherein the first host and the second host are homologues of anthracene or isomers of anthracene to each other.

[0034] In some embodiments, the wavelength of the photoluminescence spectrum of the first body and the second body is between 380nm and 470nm, and the absolute value of the difference in the wavelength of the photoluminescence spectrum of the first body and the second body is less than 10nm. Under this condition, it can be ensured that the first body and the second body have similar optical properties.

[0035] In some embodiments, the mass ratio of the first body to the second body is 1:99 to 99:1.

[0036] The study found that: (1) The mass production material crucible clogging phenomenon is mainly caused by the material crystallization phenomenon. The structures of anthracene homologues or anthracene isomers are similar, in which the anthracene unit has a large planar structure. Such a structure makes the anthracene material tend to be planar, making it easy to form π-π stacking between molecules, resulting in material accumulation and crystallization, which will cause clogging during mass production. In a material system composed of homologues or isomers, the two molecules have similar chemical properties. The two molecules will not form an excited radical complex to cause a red shift in the spectrum. On the basis of maintaining the original properties of the material, it can also improve the material crystallization phenomenon, thereby solving the mass production material crucible clogging problem. (2) Anthracene homologues or anthracene isomers can directly obtain carriers from adjacent functional layers without the need for energy transfer between them. Therefore, there is no phenomenon of carrier traps being formed due to changes in concentration ratio, which causes the device to not emit light; (3) Anthracene homologues or anthracene isomers can form good amorphous films, thereby enhancing the performance of the device and helping to increase the life of the device.

[0037] In some specific embodiments, the anthracene homologues or anthracene isomers include, but are not limited to, one selected from the compounds represented by the following structural formulas:

[0038]

[0039] In some preferred embodiments, the first body is The second subject is Or the first subject is The second subject is Or the first subject is The second subject is Or the first subject is The second subject is Or the first subject is The second subject is

[0040] It is understood that the light-emitting layer of the blue light organic electroluminescent device also includes a blue light doping material. There is no other special requirement for the selection of the blue light doping material, and the blue light doping material conventionally used in the art can be used.

[0041] In some embodiments, at least three of the hole transport layer, the electron blocking layer, the hole blocking layer, and the electron transport layer comprise a spirobifluorene derivative.

[0042] Specifically, the hole transport layer, the electron blocking layer, and the materials in the hole blocking layer and the electron transport layer all contain spirobifluorene derivatives; or

[0043] The materials in the electron blocking layer, the hole blocking layer and the electron transport layer all contain spirobifluorene derivatives; or

[0044] The materials in the hole transport layer, the hole blocking layer and the electron transport layer all contain spirobifluorene derivatives; or

[0045] The materials in the hole transport layer, the electron blocking layer and the electron transport layer all contain spirobifluorene derivatives; or

[0046] The materials in the hole transport layer, the electron blocking layer and the hole blocking layer all contain spirobifluorene derivatives.

[0047] Singlet excitons are generated by the collision and fusion of two triplet excitons, thereby improving fluorescence. This phenomenon of generating singlet excitons by the collision and fusion of two triplet excitons is referred to as TTA (triple-tripleannihilation) in the following text. In this way, triplet excitons can be effectively utilized to generate more singlet excitons, thereby improving the efficiency of the device. This requires that the functional layer adjacent to the light-emitting layer has a higher T1 in order to limit the exciton recombination area to the light-emitting layer, and the molecules on both sides of the light-emitting layer must have good stability to ensure that the material will not deteriorate and the device life will not decay in the case of continuous collisions of a large number of triplet excitons.

[0048] In this technical solution, the spirobifluorene group in the spirobifluorene derivative has a good carrier transport ability. When connected to a hole transport group, it can play a role in regulating holes. When connected to an electron transport group, it has the ability to regulate electrons. When each EL functional layer contains a large number of spirobifluorene structures, it can play a good role in regulating carriers and can optimize EL devices. (2) Since different functional layers contain the same main structure (spirobifluorene), the energy level difference of holes or electrons between different organic layers can be reduced, making the electron / hole transmission smoother, thereby improving the luminous efficiency and reducing the turn-on voltage. (3) Spirobifluorene has a higher T1 fragment. The introduction of spirobifluorene fragments into the molecule can increase the overall T1 of the material. The functional layers on both sides of the light-emitting layer introduce spirobifluorene structures, and the functional layers on both sides have higher T1, which can well confine excitons in the light-emitting layer, greatly improving the TTA effect, and thus improving the efficiency of the device. (4) Spirobifluorene structure is highly stable and resistant to the attack of exciton polaritons. Introducing spirobifluorene structure into the molecule can improve the stability of the material and avoid material cracking and the resulting attenuation of device life. (5) Spirobifluorene structure, two fluorenes are orthogonal three-dimensional structures. Its rigid three-dimensional structure can avoid π-π stacking between molecules, thereby effectively preventing the stacking of materials. To a certain extent, it can inhibit the crystallization of the material (good spatial configuration) and improve the luminescence performance.

[0049] In some embodiments, when the hole transport layer includes the spirobifluorene derivative, the energy level difference between the hole transport layer and the adjacent layer |▽HOMO|≤0.3 eV; for example, |LUMO(HBL)-LUMO(ETL)|≤0.3 eV, and |LUMO(HBL)-LUMO(Host)|≤0.3 eV, at this time, the small energy level gap is conducive to the transmission of electrons; and / or

[0050] When the spirobifluorene derivative is included in the electron transport layer, the energy level difference between the electron transport layer and the adjacent layer |▽LUMO|≤0.3eV; for example, |HOMO(HTL)-HOMO(EBL)|≤0.31eV, and |HOMO(Host)-HOMO(EBL)|≤0.3eV. At this time, the problem of slow hole transport caused by the energy level barrier can be eliminated, and the hole transport can be accelerated to a certain extent.

[0051] Those skilled in the art will appreciate that the electron transport layer may contain LiQ, and the amount of LiQ added to the electron transport layer may be added in a conventional amount. For example, when the electron transport layer contains both a spirobifluorene derivative and LiQ, the mass ratio of the spirobifluorene derivative to LiQ includes, but is not limited to, 1:1.

[0052] In some embodiments, the glass transition temperature of the spirobifluorene derivative is greater than 120° C. Under this condition, the stability of the material can be better guaranteed.

[0053] In some preferred embodiments, in the blue organic electroluminescent device, the spirobifluorene derivatives in each layer are independently selected from one of the compounds represented by the following structural formula I:

[0054]

[0055] in:

[0056] R 1 , R 2 , R 3 and R 4 are each independently selected from aryl or heteroaryl, and the adjacent R 1 , R 2 , R 3 and R 4 Can bond to form a ring;

[0057] a, b, c and d are each independently selected from integers of 0-4.

[0058] In some specific embodiments, the spirobifluorene derivative represented by the structural formula I forming the hole transport layer comprises an electron donating group; the electron donating group is selected from one or more of an aromatic amine group, a carbazole group, and a fluorene group; and / or

[0059] The spirobifluorene derivative shown in the structural formula I forming the electron transport layer comprises an electron withdrawing group; the electron withdrawing group is selected from one or more of an azine group, a phenanthroline group, a phosphino group, and a cyano group.

[0060] In some specific embodiments, the spirobifluorene derivative is selected from one of the following compounds:

[0061]

[0062] In the structure of spirobifluorene derivatives, the two fluorenes are an orthogonal three-dimensional spatial structure. Its rigid three-dimensional structure can avoid π-π stacking between molecules, thereby effectively preventing the stacking of materials. To a certain extent, it can inhibit the crystallization of materials (good spatial configuration) and improve the luminescence performance.

[0063] In addition, the structure of the spirobifluorene derivative is a fragment with a higher triplet energy level. The materials composed of the spirobifluorene structure are used on both sides of the light-emitting layer. Such materials have a high triplet energy level and can effectively block the diffusion of excitons in the light-emitting layer and improve the recombination and utilization efficiency of carriers.

[0064] When the hole transport layer / electron blocking layer on both sides of the light-emitting layer contain spirobifluorene structures, since they contain the same fragments, the HOMO energy level difference between adjacent organic layers can be reduced, further increasing the transmission of carriers and reducing the operating voltage of the device.

[0065] When the electron transport layer / hole blocking layer on both sides of the light-emitting layer contain spirobifluorene structures, since they contain the same fragments, the LUMO energy level difference between adjacent organic layers can be reduced, further increasing the transmission of carriers and reducing the operating voltage of the device.

[0066] It can be understood that the blue light organic electroluminescent device of the present invention includes a substrate, and an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode arranged in sequence on the substrate.

[0067] Yet another embodiment of the present invention provides a display device, which includes the blue organic electroluminescent device described in the above embodiment.

[0068] The technical solution of the present invention is described below in conjunction with some specific embodiments:

[0069] Some Examples of Spirobifluorene Derivatives

[0070] The crystallinity of the above spirobifluorene derivatives was tested:

[0071] The above spirobifluorene derivatives are prepared into a monolayer film, and the preparation method comprises the following steps:

[0072] The white glass plate is ultrasonically treated in a cleaning agent, rinsed in deionized water, ultrasonically degreased in an acetone-ethanol mixed solvent, and baked in a clean environment until the water is completely removed;

[0073] Place the above white glass substrate in a vacuum chamber and evacuate to 1×10 -5 ~1×10 -6Pa, deposit 50nm of the following spirobifluorene derivatives of various structures on white glass to form a single layer film on the white glass substrate, and encapsulate it for later use.

[0074] The white glass substrate with the single-layer film formed thereon was stored at 85° C. for different periods of time, and the crystallization of the film was observed. The results are shown in Table 1 below.

[0075] Table 1

[0076]

[0077]

[0078] It can be seen from the above table that the above spirobifluorene derivatives did not crystallize after being stored at high temperature for 48 hours, indicating that such compounds have good stability.

[0079] In the structure of spirobifluorene derivatives, the two fluorenes are an orthogonal three-dimensional spatial structure. Its rigid three-dimensional structure can avoid π-π stacking between molecules, thereby effectively preventing the stacking of materials. To a certain extent, it can inhibit the crystallization of materials (good spatial configuration) and improve the luminescence performance.

[0080] Some examples of anthracene homologues or anthracene isomers

[0081] The structural formulas of some anthracene homologues or anthracene isomers used in the examples are shown in Table 2 below.

[0082] Table 2

[0083]

[0084] 1) Calculate the electron cloud distribution in the molecular structure of the above anthracene homologues or anthracene isomers:

[0085] The calculation was specifically performed using the computational chemistry software "Spartan'18". The DFT (Density Functional Theory) method was used to calculate the energy level and electron cloud distribution of the equilibrium geometry in the ground state at the B3LYP / 6-31g* calculation level. The results are shown in Table 3 below.

[0086] Table 3

[0087]

[0088] As shown in the table above, the electron clouds of the anthracene isomers are distributed in the plane where the anthracene is located, and it is difficult for the electrons to be delocalized to the surrounding peripheral groups. In addition, the energy levels of the isomers are similar through simulation calculations, indicating that the anthracene isomers have similar electrical properties.

[0089] 2) Testing the photoluminescence spectra of the above anthracene isomers:

[0090] The test results of the photoluminescence spectra of the two structural formulas of BH-4, structural formula 1 and structural formula 2 alone, and the BH-4 formed by the mixture of structural formula 1 and structural formula 2 are as follows: Figure 1 As shown. Figure 1 The spectral data showed that the spectral properties of the monomer and the isomeric system were similar, and no exciplex was formed, thus avoiding the spectral red shift.

[0091] The luminescence spectra of BH-1, BH-2, BH-3 and BH-5 obtained by mixing the two structural formulas of BH-1, BH-2, BH-3 and BH-5 separately and the monomers were tested in the above manner. The results were similar to those mentioned above. After mixing the two monomers of BH-1, BH-2, BH-3 and BH-5, no excited complex was formed, thus avoiding the red shift of the spectrum.

[0092] 3) Testing the crystallinity of the anthracene isomers:

[0093] A single-layer film is prepared from each anthracene isomer, and the preparation method comprises the following steps:

[0094] The white glass plate is ultrasonically treated in a cleaning agent, rinsed in deionized water, ultrasonically degreased in an acetone-ethanol mixed solvent, and baked in a clean environment until the water is completely removed;

[0095] Place the above white glass substrate in a vacuum chamber and evacuate to 1×10 -5 ~1×10 -6 Pa, deposit 50nm of anthracene isomers with various structures as follows on white glass to form a single layer film on the white glass substrate, and package it for later use.

[0096] The white glass substrate with the single-layer film was stored at 85°C for different periods of time and the crystallization of the film was observed. The results are shown in Table 4 below (in Table 4, the ratio of each structural formula 1 to structural formula 2 is a mass ratio).

[0097] Table 4

[0098]

[0099] As can be seen from Table 4 above, the single-component anthracene unit in the isomers of anthracene alone has a relatively large planar structure, which makes its molecular structure tend to be planar, making it easy for molecules to form π-π stacking, resulting in material accumulation, which in turn triggers crystallization, which can cause pore blocking during mass production. The material system composed of two homologues or isomers of anthracene will not crystallize during long-term high-temperature storage, thereby solving the problem of pore blocking in the crucible of mass production materials.

[0100] The crystallinity analysis of the two structural formulas of BH-1, BH-3 and BH-5 was further tested in the above manner, and the results obtained were similar to those mentioned above. The material system composed of homologues or isomers of anthracene will not crystallize when stored at high temperature for a long time.

[0101] Some embodiments of blue organic electroluminescent devices

[0102] Example

[0103] The structure of the device includes: an indium tin oxide ITO layer on a glass substrate as an anode, a hole injection layer HIL (5-30nm), a hole transport layer HTL (100-2000nm), an electron blocking layer EBL (5-100nm), a light-emitting layer EML (20-100nm), a hole blocking layer HBL (5-100nm), an electron transport layer ETL (20-100nm), an electron injection layer EIL (1-10nm), and a cathode.

[0104] Specifically: The optional materials for each functional layer are as follows, but not limited to:

[0105] 1.HIL: can be inorganic oxides, such as MoO 3 , F4-TCNQ, HAT-CN, etc., but not limited to these.

[0106] 2. HTL: aromatic amine or carbazole materials with hole transport properties, such as NPB, m-MTDATA, TPD, etc., or the spirobifluorene derivatives of the present invention, but not limited thereto.

[0107] 3. EBL: aromatic amine or carbazole materials with hole transport properties, such as mCBP, Tris-PCz, etc., or the spirobifluorene derivatives of the present invention, but not limited thereto.

[0108] 4. Host: AND, TBADN, MADN, or a homologue of anthracene or an isomer of anthracene in the present invention.

[0109] 5.Dopant: Dpvbi, DPAVB, DSA-Ph, etc.

[0110] 6. HBL: The hole blocking layer is generally an aromatic heterocyclic compound, such as BCP, Bphen, etc., or the spirobifluorene derivatives in the present invention, but is not limited thereto.

[0111] 7.ETL: The electron transport layer is generally an aromatic heterocyclic compound, such as TPBi, Bphen, etc., or the spirobifluorene derivatives in the present invention, but is not limited thereto.

[0112] 8. EIL: generally alkali metal or metal, LiF, Yb, LiQ, etc., but not limited to these.

[0113] Device preparation process:

[0114] The preparation process of the organic electroluminescent device described in the device embodiment of the present invention is as follows:

[0115] (1) ultrasonically treating the glass plate with ITO in a cleaning agent, rinsing it in deionized water, ultrasonically degreasing it in an acetone-ethanol mixed solvent, and baking it in a clean environment until the water is completely removed;

[0116] (2) Place the glass substrate with the anode in a vacuum chamber and evacuate the chamber to a vacuum of 1×10 -5 ~1×10 -6 Pa, vacuum evaporating a hole injection material on the anode layer film to form a hole injection material;

[0117] (3) evaporating a hole transport material on the hole injection layer to form a hole transport layer;

[0118] (4) depositing an electron blocking layer of a hole transporting element on the hole transporting layer by a vacuum evaporator;

[0119] (5) vacuum evaporating a light-emitting layer of the device on the electron blocking layer, wherein the light-emitting layer includes a host material and a guest material, and a weight ratio of the host material to the guest material is 97:3 by a multi-source co-evaporation method;

[0120] (6) vacuum evaporating a hole blocking layer of the device on the light-emitting layer;

[0121] (7) an electron transport layer of a vacuum-deposited device on the hole blocking layer;

[0122] (8) Vacuum evaporation of 1 nm thick LiF on the electron transport layer (ETL) as an electron injection layer;

[0123] (9) An Al layer is evaporated on the electron injection layer as the cathode of the device.

[0124] The above implementation method is adopted to produce the organic EL devices in the following table by evaporating the following materials on different functional layers. The specific materials are shown in Table 5 below.

[0125] Table 5

[0126]

[0127]

[0128] Among them, some of the materials used in the above Table 5 are as follows:

[0129]

[0130] In the above embodiments, in the organic electroluminescent device, when the HTL layer, the EBL layer, the HBL layer and the ETL layer all contain the spirobifluorene derivative in the technical solution, the structural schematic diagram of the HTL layer, the EBL layer, the EML layer, the HBL layer and the ETL layer in the device is as follows: Figure 2 shown.

[0131] When the HTL layer, the EBL layer and the HBL layer all contain the spirobifluorene derivative in the technical solution in the organic electroluminescent device, but the ETL layer does not contain it, the structural schematic diagram of the HTL layer, the EBL layer, the EML layer, the HBL layer and the ETL layer in the device is as follows: Figure 3 shown.

[0132] When the EBL layer, the HBL layer and the ETL layer all contain the spirobifluorene derivative of the technical solution in the organic electroluminescent device, but the HTL layer does not contain it, the structural schematic diagram of the HTL layer, the EBL layer, the EML layer, the HBL layer and the ETL layer in the device is as follows: Figure 4 shown.

[0133] When the HTL layer, the EBL layer and the ETL layer all contain the spirobifluorene derivative in the technical solution in the organic electroluminescent device, but the HBL layer does not contain the spirobifluorene derivative, the structural schematic diagram of the HTL layer, the EBL layer, the EML layer, the HBL layer and the ETL layer in the device is as follows: Figure 5 shown.

[0134] When the HTL layer, the ETL layer and the HBL layer all contain the spirobifluorene derivative in the technical solution in the organic electroluminescent device, but the EBL layer does not contain it, the structural schematic diagram of the HTL layer, the EBL layer, the EML layer, the HBL layer and the ETL layer in the device is as follows: Figure 6 shown.

[0135] The organic light-emitting diode manufactured by the above method has the following specific layers in the device: ITO / HIL (10nm) / HTL (100nm) / EBL (10nm) / Host1, Host2: Dopant (1:1, 3wt%, 20nm)) / HBL (5nm) / ETL: LiQ (1:1, 30nm) / EIL (1nm) / cathode (100nm), and at a fixed current density of 15mA / cm 2 The driving voltage and luminous efficiency were measured and the results are shown in Table 6.

[0136] Table 6

[0137] Example Voltage efficiency life <![CDATA[CIE x ]]> <![CDATA[CIE y ]]> Example 1 94.23％ 110.59％ 113.24％ 0.134 0.120 Example 2 95.35％ 109.26％ 108.18％ 0.134 0.125 Example 3 93.62％ 105.85％ 107.86％ 0.133 0.125 Example 4 93.54％ 108.45％ 109.41％ 0.135 0.124 Example 5 94.89％ 107.91％ 108.83％ 0.135 0.124 Example 6 97.72％ 101.52％ 103.76％ 0.135 0.121 Example 7 102.30％ 104.43％ 103.68％ 0.135 0.113 Example 8 99.15％ 102.94％ 104.22％ 0.134 0.121 Example 9 99.27％ 101.73％ 101.66％ 0.134 0.120 Example 10 100.71％ 102.89％ 102.06％ 0.134 0.120 Embodiment 11 94.75％ 107.23％ 106.87％ 0.133 0.121 Example 12 101.25％ 101.04％ 99.01％ 0.135 0.123 Embodiment 13 99.27％ 101.73％ 100.66％ 0.134 0.120 Embodiment 14 100.71％ 100.89％ 99.06％ 0.134 0.120 Embodiment 15 100.00％ 100.00％ 100.00％ 0.134 0.119

[0138] Note: Take the data of Example 15 as a reference, and set its voltage, efficiency and life data to 100%.

[0139] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A blue light organic electroluminescent device, comprising a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer and an electron transport layer arranged in sequence, characterized in that: The light-emitting layer at least includes a first main body and a second main body; wherein the first host and the second host are homologues of anthracene or isomers of anthracene; At least three of the hole transport layer, the electron blocking layer, the hole blocking layer and the electron transport layer contain a spirobifluorene derivative.

2. The blue organic electroluminescent device according to claim 1, characterized in that: The wavelengths of the photoluminescence spectra of the first body and the second body are between 380nm and 470nm, and the absolute value of the difference between the wavelengths of the photoluminescence spectra of the first body and the second body is less than 10nm.

3. The blue organic electroluminescent device according to claim 1, characterized in that: The mass ratio of the first body to the second body is 1:99 to 99:

1.

4. The blue organic electroluminescent device according to any one of claims 1 to 3, characterized in that: The anthracene homologue or anthracene isomer is selected from one of the compounds represented by the following structural formulas:

5. The blue organic electroluminescent device according to claim 1, characterized in that: When the hole transport layer contains the spirobifluorene derivative, the energy level difference between the hole transport layer and the adjacent layer |▽HOMO|≤0.3 eV; and / or When the electron transport layer includes the spirobifluorene derivative, the energy level difference between the electron transport layer and an adjacent layer |▽LUMO|≤0.3 eV.

6. The blue organic electroluminescent device according to claim 1 or 5, characterized in that: The glass transition temperature of the spirobifluorene derivative is greater than 120°C.

7. The blue organic electroluminescent device according to claim 6, characterized in that: The spirobifluorene derivatives in each layer are independently selected from one of the compounds represented by the following structural formula I: in: R1, R2, R3 and R4 are each independently selected from an aryl group or a heteroaryl group, and adjacent R1, R2, R3 and R4 may be bonded to form a ring; a, b, c and d are each independently selected from integers of 0-4.

8. The blue organic electroluminescent device according to claim 7, characterized in that: The spirobifluorene derivative shown in the structural formula I that forms the hole transport layer contains an electron-donating group; the electron-donating group is selected from one or more of a substituted or unsubstituted aromatic amine group, a substituted or unsubstituted carbazole group, and a substituted or unsubstituted fluorene group.

9. The blue organic electroluminescent device according to claim 7, characterized in that: The spirobifluorene derivative shown in the structural formula I that forms the electron transport layer contains an electron withdrawing group; the electron withdrawing group is selected from one or more of a substituted or unsubstituted azine group, a substituted or unsubstituted phenanthroline group, a substituted or unsubstituted phosphino group, and a substituted or unsubstituted cyano group.

10. A display device, characterized in that: The invention comprises the blue organic electroluminescent device as claimed in any one of claims 1 to 9.

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