Blue light-emitting main body composition and organic electroluminescent device and display device comprising same

Abstract

The invention discloses a blue light-emitting main body composition, and an organic electroluminescent device and a display device comprising the same. The blue light-emitting main body composition at least comprises a first main body compound, a second main body compound and a third main body compound; the structure of the first host compound is as shown in a formula I, the structure of the second host compound is as shown in a formula II, and the structure of the third host compound is as shown in the formula I or the formula II. The melting point of the blue light-emitting main body composition provided by the invention is lower than that of each single compound, and the blue light-emitting main body composition provided by the invention is evaporated under continuous working conditions and different evaporation rates to form a main body composition film; the mass ratio of the blue light-emitting main body composition provided by the invention in a finally evaporated film is relatively constant, and the difference between the mass ratio and the initial premixing ratio is small, so that the problem that the performance of a device is reduced due to the fact that the difference between the actual evaporation component ratio and the initially set premixing ratio is large is avoided. # imgabs0 # I and # imgabs1 # II

Description

Technical Field

[0001] The present invention belongs to the technical field of OLEDs, and specifically comprises a blue light-emitting host composition and an organic electroluminescent device and a display device comprising the same. Background Art

[0002] Organic electroluminescent devices (OLEDs), as a promising semiconductor light-emitting technology, have made significant research progress in materials science, device structure, performance optimization and industrial application in recent years. How to further improve the comprehensive performance of blue light organic electroluminescent devices is a hot topic in current research.

[0003] Existing premixed dual-host blue fluorescent light-emitting devices have significant advantages. Their dual-host materials achieve good carrier balance by optimizing energy level matching, which not only reduces the driving voltage and improves the luminous efficiency, but also effectively suppresses the efficiency roll-off. At present, when preparing premixed dual-host blue fluorescent light-emitting devices, the two host materials are usually premixed according to a preset mass ratio before evaporation, and then evaporated in an evaporation source. However, during the evaporation process, the two host components in the premixed material are often not evaporated according to the premixed ratio, resulting in a large difference between the ratio of the two host materials in the actual evaporated film layer and the initial preset ratio, which in turn leads to a reduction in its lifespan and needs further optimization. In addition, it is difficult to keep the ratio of the two host materials constant under different evaporation speeds. As a result, when the evaporation speed changes, the device performance may also fluctuate, and the stability is poor, which greatly affects the production of the device under continuous working conditions. Summary of the Invention

[0004] In view of the above problems existing in the prior art, the present invention provides a blue light-emitting host composition and an organic electroluminescent device comprising the same.

[0005] To achieve the above objectives, the technical solutions adopted by the present invention include: A first aspect of the present invention provides a blue light-emitting host composition comprising at least a first host compound, a second host compound, and a third host compound; the structure of the first host compound is as shown in Formula I, the structure of the second host compound is as shown in Formula II, and the structure of the third host compound is as shown in Formula I or Formula II; the first host compound, the second host compound, and the third host compound are different from each other; I. II; wherein Ar1 and Ar2 are each independently selected from any one or a combination of any two of a deuterated or non-deuterated aryl group having 6 to 30 carbon atoms, a deuterated or non-deuterated fused ring aryl group having 10 to 30 carbon atoms; Ar3 is selected from any one or a combination of any two of a deuterated or non-deuterated aryl group having 6 to 30 carbon atoms, a deuterated or non-deuterated fused ring aryl group having 10 to 30 carbon atoms; Ar4 is selected from any one or a combination of any two of a deuterated or non-deuterated heterocyclic group having 5 to 30 carbon atoms and containing an oxygen atom, and a deuterated or non-deuterated fused-ring heterocyclic group having 5 to 30 carbon atoms and containing an oxygen atom; L1, L2, L3, and L4 are each independently selected from any one of a single bond, a deuterated or non-deuterated aromatic group having 6 to 30 carbon atoms; The mass proportion of any one host compound in the blue light-emitting host composition is between 10 and 80 wt %.

[0006] Furthermore, Ar1 and Ar2 are each independently selected from any one or a combination of any two of a deuterated or non-deuterated aryl group having 6 to 20 carbon atoms and a deuterated or non-deuterated fused ring aryl group having 10 to 20 carbon atoms.

[0007] Furthermore, Ar3 is selected from any one or a combination of any two of a deuterated or non-deuterated aryl group having 6 to 20 carbon atoms, a deuterated or non-deuterated fused ring aryl group having 10 to 20 carbon atoms.

[0008] Furthermore, Ar4 is selected from any one or a combination of any two of a deuterated or non-deuterated heterocyclic group having 5 to 20 carbon atoms and containing an oxygen atom, and a deuterated or non-deuterated fused-ring heterocyclic group having 5 to 20 carbon atoms and containing an oxygen atom.

[0009] Furthermore, L1, L2, L3, and L4 are each independently selected from a single bond, a deuterated or non-deuterated aromatic group having 6 to 20 carbon atoms.

[0010] Furthermore, the mass proportion of any one compound in the blue light-emitting host composition is between 10 and 75 wt %.

[0011] Furthermore, the mass proportion of any one compound in the blue light-emitting host composition is between 10 and 70 wt %.

[0012] Furthermore, the mass proportion of any one compound in the blue light-emitting host composition is between 10 and 65 wt %.

[0013] Furthermore, the mass proportion of any one compound in the blue light-emitting host composition is between 10 and 60 wt %.

[0014] Furthermore, the total mass of the compounds selected from Formula I in the blue light-emitting host composition accounts for no less than 10 wt % of the mass of the blue light-emitting host composition.

[0015] Furthermore, the total mass of the compounds selected from Formula I in the blue light-emitting host composition accounts for no less than 20 wt % of the mass of the blue light-emitting host composition.

[0016] Furthermore, the total mass of the compounds selected from Formula I in the blue light-emitting host composition accounts for no less than 30 wt % of the mass of the blue light-emitting host composition.

[0017] Furthermore, the total mass of the compounds selected from Formula I in the blue light-emitting host composition accounts for no less than 40 wt % of the mass of the blue light-emitting host composition.

[0018] Furthermore, the total mass of the compounds selected from Formula II in the blue light-emitting host composition accounts for no less than 10 wt % of the mass of the blue light-emitting host composition.

[0019] Furthermore, the total mass of the compounds selected from Formula II in the blue light-emitting host composition accounts for no less than 20 wt % of the mass of the blue light-emitting host composition.

[0020] Furthermore, the total mass of the compounds selected from Formula II in the blue light-emitting host composition accounts for no less than 30 wt % of the mass of the blue light-emitting host composition.

[0021] Furthermore, the total mass of the compounds selected from Formula II in the blue light-emitting host composition accounts for no less than 40 wt % of the mass of the blue light-emitting host composition.

[0022] In combination with the first aspect, the ratio of the total mass of the compounds selected from Formula I to the total mass of the compounds selected from Formula II in the blue light-emitting host composition is 1:9~9:1.

[0023] Furthermore, the ratio of the total mass of the compounds selected from Formula I to the total mass of the compounds selected from Formula II in the blue light-emitting host composition is 2:8~8:2.

[0024] Furthermore, the ratio of the total mass of the compounds selected from Formula I to the total mass of the compounds selected from Formula II in the blue light-emitting host composition is 3:7 to 7:3.

[0025] Furthermore, the ratio of the total mass of the compounds selected from Formula I to the total mass of the compounds selected from Formula II in the blue light-emitting host composition is 4:6~6:4.

[0026] Furthermore, the above-mentioned oxygen-containing heterocyclic group preferably includes furyl, etc.; Preferred examples of the oxygen-containing fused-ring heterocyclic group include dibenzofuranyl, naphthobenzofuranyl, and benzo[4,5-BCD]furanyl.

[0027] In combination with the first aspect, Ar1 and Ar2 are each independently selected from any one or a combination of any two of deuterated or non-deuterated phenyl, deuterated or non-deuterated biphenyl, deuterated or non-deuterated naphthyl, and deuterated or non-deuterated phenanthryl; Ar3 is selected from any one or a combination of any two of deuterated or non-deuterated phenyl, deuterated or non-deuterated biphenyl, and deuterated or non-deuterated naphthyl; Ar4 is selected from 、 、 、 Any of the following, any hydrogen in Ar4 can be replaced by deuterium; L1, L2, L3, and L4 are each independently selected from any one of a single bond, a deuterated or non-deuterated phenyl group, and a deuterated or non-deuterated biphenyl group; When the third host compound is selected from the structure shown in Formula I, in the blue light-emitting host composition, the mass ratio of the first host compound, the second host compound and the third host compound is 0.1-6:0.5-7:1; When the third host compound is selected from the structure shown in Formula II, in the blue light-emitting host composition, the mass ratio of the first host compound, the second host compound and the third host compound is 0.5~7:0.1~6:1.

[0028] In combination with the first aspect, the difference in molecular weight between any two of the above-mentioned first host compound, second host compound and third host compound is within 100, that is, the difference in molecular weight between the first host compound and the second host compound is within 100, the difference in molecular weight between the first host compound and the third host compound is within 100, and the difference in molecular weight between the second host compound and the third host compound is within 100.

[0029] In combination with the first aspect, when the first host compound, the second host compound and the third host compound are deuterated compounds, the deuteration rate of each deuterated site in their structure is greater than 5%.

[0030] Furthermore, Formula I is selected from one of the structures shown below:

[0031]

[0032]

[0033] ; Wherein, Dn represents that n hydrogens are replaced by deuterium, and n is a positive integer ranging from 1 to the maximum deuterium generation number.

[0034] by To illustrate, it can represent When any hydrogen is replaced by deuterium, e.g. 、 、 、 wait.

[0035] In combination with the first aspect, Formula II is selected from one of the structures shown below:

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] ; Wherein, Dn represents that n hydrogens are replaced by deuterium, and n is a positive integer ranging from 1 to the maximum deuterium generation number.

[0049] Furthermore, the blue light-emitting host composition is selected from any one of the following: Composition 1:

[0050] Composition 2:

[0051] Composition 3:

[0052] Composition 4:

[0053] Composition 5:

[0054] Composition 6:

[0055] Composition 7:

[0056] Composition 8:

[0057] Composition 9:

[0058] Composition 10:

[0059] Composition 11:

[0060] Composition 12:

[0061] Composition 13:

[0062] Composition 14:

[0063] Composition 15:

[0064] Composition 16:

[0065] Composition 17:

[0066] Composition 18:

[0067] Composition 19:

[0068] Composition 20:

[0069] Composition 21:

[0070] Composition 22:

[0071] Composition 23:

[0072] Composition 24:

[0073] Composition 25:

[0074] Composition 26:

[0075] Composition 27:

[0076] Composition 28:

[0077] Composition 29: ; In each composition, compound A-1 to compound A-29 are first main compounds, compound B-1 to compound B-29 are second main compounds, and compound C-1 to compound C-29 are third main compounds.

[0078] A second aspect of the present invention provides an organic electroluminescent device, which includes an anode, a hole transport region, a light-emitting layer, an electron transport region, and a cathode sequentially arranged on a substrate; wherein the light-emitting layer includes the blue light-emitting host composition as described above.

[0079] Furthermore, the light-emitting layer includes a host material and a guest material, wherein the host material includes the blue light-emitting host composition described above.

[0080] A third aspect of the present invention provides a display device comprising the organic electroluminescent device described above.

[0081] Beneficial effects of the present invention: The blue light-emitting host composition disclosed in the present invention comprises at least three different compounds, namely a first host compound, a second host compound and a third host compound. The compositions defined in the present invention are combined within the mass ratio range defined in the present invention to form a blue light-emitting host composition, the melting point of which is lower than the melting point of each single compound; the blue light-emitting host compound provided by the present invention is evaporated under continuous working conditions and different evaporation rates to form a host composition film, the mass ratio of the blue light-emitting host composition provided by the present invention in the film after final evaporation is relatively constant, and is slightly different from the initial premixed ratio. The blue light-emitting host composition provided by the present invention is applied to a blue organic electroluminescent device as a host material of a light-emitting layer. The blue light-emitting host composition provided by the present invention can not only significantly reduce the device driving voltage, but also significantly extend the device life. Moreover, under continuous working conditions, the voltage efficiency and life of the organic electroluminescent device prepared from the blue light-emitting host composition provided by the present invention are relatively stable, indicating that the blue light-emitting host composition provided by the present invention makes it easier to obtain an organic electroluminescent device with excellent performance and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 Schematic diagram of the structure of the organic electroluminescent device of the present invention, wherein 1-substrate, 2-anode, 3-hole injection layer, 4-hole transport layer, 5-luminescence auxiliary layer, 6-luminescent layer, 7-hole blocking layer, 8-electron transport layer, 9-electron injection layer, 10-cathode, and 11-covering layer.

[0083] Figure 2 is the DSC curve of compound A-1.

[0084] Figure 3 is the DSC curve of compound B-1.

[0085] Figure 4 is the DSC curve of compound C-1.

[0086] Figure 5 The DSC curve of the composition in which compounds A-1, B-1 and C-1 are mixed in a mass ratio of 2:5:3 is shown.

[0087] Figure 6 The DSC curve of the composition in which compounds A-1 and B-1 were mixed at a mass ratio of 5:5 is shown. DETAILED DESCRIPTION

[0088] In order to more clearly understand the content of the present invention, it will be described in detail with reference to the accompanying drawings and embodiments.

[0089] The compounds of the present invention are suitable for use in light-emitting elements, display panels and electronic devices, and are particularly suitable for use in organic electroluminescent devices. The electronic device described in the present invention is a device comprising a layer of at least one organic compound, which may also comprise an inorganic material or a layer formed entirely of an inorganic material. The electronic device is preferably an organic electroluminescent device (OLED), an organic integrated circuit (O-IC), an organic field effect transistor (O-FET), an organic thin film transistor (O-TFT), an organic light-emitting transistor (O-LET), an organic solar cell (O-SC), an organic dye-sensitized solar cell (O-DSSC), an organic optical detector, an organic photoreceptor, an organic field quenching device (O-FQD), a light-emitting electrochemical cell (LEC), an organic laser diode (O-laser) and an organic plasma emission device. The electronic device is preferably an organic electroluminescent device (OLED). The structural schematic diagram of an exemplary organic electroluminescent device is shown in FIG. Figure 1 shown.

[0090] Experimental part In order to understand the content of the present invention more clearly, the polycyclic compound, the preparation method of the compound and the luminescent characteristics of the device will be explained in detail in conjunction with the examples. Various chemical reactions can be applied to the synthetic method of the compound of one embodiment of the present invention. However, it should be noted that the synthetic method of the compound of one embodiment of the present invention is not limited to the synthetic method described below. Unless otherwise stated, subsequent synthesis is carried out in an anhydrous solvent under a protective gas atmosphere. Solvents and reagents can be purchased from conventional reagent suppliers.

[0091] The compounds used in the following compositions can be purchased from outside or synthesized in-house.

[0092] Composition Example 1 This embodiment provides a blue light-emitting host composition, which is composed of compound A-1, compound B-1 and compound C-1. The mass proportions of each compound are shown in Table 1: .

[0093] Composition Example 2 This embodiment provides a blue light-emitting host composition, which is composed of compound A-2, compound B-2 and compound C-2. The mass proportions of each compound are shown in Table 1: .

[0094] Composition Example 3 This embodiment provides a blue light-emitting host composition, which is composed of compound A-3, compound B-3 and compound C-3. The mass proportions of each compound are shown in Table 1: .

[0095] Composition Example 4 This embodiment provides a blue light-emitting host composition, which is composed of compound A-4, compound B-4 and compound C-4. The mass proportions of each compound are shown in Table 1: .

[0096] Composition Example 5 This embodiment provides a blue light-emitting host composition, which is composed of compound A-5, compound B-5 and compound C-5. The mass proportions of each compound are shown in Table 1: .

[0097] Composition Example 6 This embodiment provides a blue light-emitting host composition, which is composed of compound A-6, compound B-6 and compound C-6. The mass proportions of each compound are shown in Table 1: .

[0098] Composition Example 7 This embodiment provides a blue light-emitting host composition, which is composed of compound A-7, compound B-7 and compound C-7. The mass proportions of each compound are shown in Table 1: .

[0099] Composition Example 8 This embodiment provides a blue light-emitting host composition, which is composed of compound A-8, compound B-8 and compound C-8. The mass proportions of each compound are shown in Table 1: .

[0100] Composition Example 9 This embodiment provides a blue light-emitting host composition, which is composed of compound A-9, compound B-9 and compound C-9. The mass proportions of each compound are shown in Table 1: .

[0101] Composition Example 10 This embodiment provides a blue light-emitting host composition, which is composed of compound A-10, compound B-10 and compound C-10. The mass proportions of each compound are shown in Table 1: .

[0102] Composition Example 11 This embodiment provides a blue light-emitting host composition, which is composed of compound A-11, compound B-11 and compound C-11. The mass proportions of each compound are shown in Table 1: .

[0103] Composition Example 12 This embodiment provides a blue light-emitting host composition, which is composed of compound A-12, compound B-12 and compound C-12. The mass proportions of each compound are shown in Table 1: .

[0104] Composition Example 13 This embodiment provides a blue light-emitting host composition, which is composed of compound A-13, compound B-13 and compound C-13. The mass proportions of each compound are shown in Table 1: .

[0105] Composition Example 14 This embodiment provides a blue light-emitting host composition, which is composed of compound A-14, compound B-14 and compound C-14. The mass proportions of each compound are shown in Table 1: .

[0106] Composition Example 15 This embodiment provides a blue light-emitting host composition, which is composed of compound A-15, compound B-15 and compound C-15. The mass proportions of each compound are shown in Table 1: .

[0107] Composition Example 16 This embodiment provides a blue light-emitting host composition, which is composed of compound A-16, compound B-16 and compound C-16. The mass proportions of each compound are shown in Table 1: .

[0108] Composition Example 17 This embodiment provides a blue light-emitting host composition, which is composed of compound A-17, compound B-17 and compound C-17. The mass proportions of each compound are shown in Table 1: .

[0109] Composition Example 18 This embodiment provides a blue light-emitting host composition, which is composed of compound A-18, compound B-18 and compound C-18. The mass proportions of each compound are shown in Table 1: .

[0110] Composition Example 19 This embodiment provides a blue light-emitting host composition, which is composed of compound A-19, compound B-19 and compound C-19. The mass proportions of each compound are shown in Table 1: .

[0111] Composition Example 20 This embodiment provides a blue light-emitting host composition, which is composed of compound A-20, compound B-20 and compound C-20. The mass proportions of each compound are shown in Table 1: .

[0112] Composition Example 21 This embodiment provides a blue light-emitting host composition, which is composed of compound A-21, compound B-21 and compound C-21. The mass proportions of each compound are shown in Table 1: .

[0113] Composition Example 22 This embodiment provides a blue light-emitting host composition, which is composed of compound A-22, compound B-22 and compound C-22. The mass proportions of each compound are shown in Table 1: .

[0114] Composition Example 23 This embodiment provides a blue light-emitting host composition, which is composed of compound A-23, compound B-23 and compound C-23. The mass proportions of each compound are shown in Table 1: .

[0115] Composition Example 24 This embodiment provides a blue light-emitting host composition, which is composed of compound A-24, compound B-24 and compound C-24. The mass proportions of each compound are shown in Table 1: .

[0116] Composition Example 25 This embodiment provides a blue light-emitting host composition, which is composed of compound A-25, compound B-25 and compound C-25. The mass proportions of each compound are shown in Table 1: .

[0117] Composition Example 26 This embodiment provides a blue light-emitting host composition, which is composed of compound A-26, compound B-26 and compound C-27. The mass proportions of each compound are shown in Table 1: .

[0118] Composition Example 28 This embodiment provides a blue light-emitting host composition, which is composed of compound A-28, compound B-28 and compound C-28. The mass proportions of each compound are shown in Table 1: .

[0119] Composition Example 29 This embodiment provides a blue light-emitting host composition, which is composed of compound A-29, compound B-29 and compound C-29. The mass proportions of each compound are shown in Table 1: .

[0120] Table 1

[0121] Note: The mass proportion of each compound in Table 1 refers to the mass proportion of each host compound in the corresponding blue light-emitting host composition.

[0122] Fabrication and characterization of OLEDs Device Examples The organic electroluminescent device provided by the present invention comprises an anode, a hole transport region, a light-emitting layer, an electron transport region, and a cathode which are sequentially arranged on a substrate; Furthermore, the hole transport region includes a hole injection layer, a hole transport layer and a light-emitting auxiliary layer; and the electron transport region includes an electron transport layer and an electron injection layer.

[0123] Furthermore, the light-emitting layer is composed of a host material and a guest material, and the host material of the light-emitting layer can be composed of one molecular material or multiple molecular materials.

[0124] The composition of the present invention can be used in the light-emitting layer of the above-mentioned organic electroluminescent device.

[0125] The anode in the embodiment adopts anode materials commonly used in the art, such as ITO, Ag or their multilayer structures. The hole injection layer adopts hole injection materials commonly used in the art, and F4TCNQ, HATCN, NDP-9, etc. are added for doping. The hole transport layer adopts hole transport materials commonly used in the art. The light-emitting layer adopts the host and guest material composition provided by the present invention. The electron transport layer adopts electron transport materials commonly used in the art. The electron injection layer adopts electron injection materials commonly used in the art, such as LiQ, LiF, Yb, etc. The cathode adopts materials commonly used in the art, such as metal Al, Ag or metal mixtures (Ag-doped Mg, Ag-doped Ca, etc.).

[0126] The electrode preparation method and the deposition method of each functional layer in this embodiment are conventional methods in the art, such as vacuum thermal evaporation or inkjet printing, and will not be described in detail here. Only some process details and testing methods in the preparation process are supplemented as follows: Device Example 1 The substrates used in the present invention were subjected to the following operations: the ITO substrate was patterned to have a light-emitting area of ​​3 mm × 3 mm, and then subjected to water / isopropyl alcohol ultrasonic treatment, UV / ozone irradiation, and then dried at 100 ° C. After that, the ITO substrate was mounted on a substrate holder of a vacuum deposition device and the pressure was adjusted to a vacuum rate of 1 × 10 -7 torr. The following operations were then performed: first, on the ITO layer (anode) formed on the substrate, compound HT01 and compound PD01 (the mass ratio of compound HT01 to compound PD01 was 97:3) were vacuum deposited with a thickness of 10 nm to form a hole injection layer; secondly, on the hole injection layer, compound HT01 was vacuum deposited with a thickness of 100 nm to form a hole transport layer; secondly, on the hole transport layer, compound BP01 was vacuum deposited with a thickness of 5 nm to form a luminescent auxiliary layer; thirdly, on the luminescent auxiliary layer, a mixture of composition embodiment 1 provided by the present invention and compound BD01 was vacuum deposited with a thickness of 20 nm to form a luminescent layer, wherein composition embodiment 1 was used as a host material and compound BD01 was used as a guest material, and the mass ratio of composition embodiment 11 to the guest material was 98:2; then, on the luminescent layer, compound HB01 was vacuum deposited with a thickness of 5 nm to form a hole blocking layer. layer; then, on the hole blocking layer, compound ET01 and compound LiQ (the mass ratio of compound ET01 to compound LiQ is 1:1) are vacuum deposited with a thickness of 30 nm to form an electron transport layer; then, on the electron transport layer, Yb is vacuum deposited with a thickness of 1 nm to form an electron injection layer, and then on the electron injection layer, Mg and Ag (the mass ratio of Mg to Ag is 1:9) are deposited with a thickness of 15 nm to form a cathode, and then on the cathode, compound CP01 is deposited with a thickness of 50 nm to form a covering layer. Finally, the evaporated substrate is packaged, and the cleaned cover is coated with UV glue using a glue coating device, and the coated cover is then moved to the pressing section, and the evaporated substrate is placed on the upper end of the cover. Finally, the substrate and cover are bonded together using a bonding device, and the UV glue is light-cured to prepare a top-emitting organic electroluminescent device. The device structure is shown in FIG. Figure 1 .

[0127] Except for the host and guest materials of the light-emitting layer, the molecular structures of the materials in the remaining layers are as follows:

[0128]

[0129]

[0130] Device Examples 2-5 The above method was used to prepare organic electroluminescent devices using the composition examples 2 to 5 provided by the present invention as host materials, respectively, to obtain device examples 2-5.

[0131] Device Comparative Examples 1-3 The host composition in Table 2 was prepared into organic electroluminescent devices using the above method. For specific component combinations, see Table 2, to obtain device comparative examples 1-3.

[0132] The OLED devices described above were tested by standard methods. For this purpose, at J = 10 mA / cm 2 The driving voltage and luminous efficiency of the organic electroluminescent device are determined at a current density of J = 20 mA / cm 2 When working under this condition, the luminous brightness drops to 97% of its initial value L0 after time LT97.

[0133] The test instruments and methods for performing performance tests on the OLED devices of the above embodiments and comparative examples are as follows: Luminous efficiency CE (cd / A) and color coordinates (CIEy) were tested using a spectrum scanner PhotoResearch PR-635. Current density and lighting voltage: tested using a Keithley 2400 digital source meter; The luminous efficiency of blue light devices is greatly affected by chromaticity. The industry generally uses the BI value as the basis for the efficiency of blue light devices. BI (Blue Index) is obtained by dividing the luminous efficiency CE (cd / A) by the color coordinate (CIEy). Life test: Use silicon photoelectric OLED device life test system.

[0134] The performance test results of the above devices are listed in Table 2.

[0135] Table 2 Blue light device performance test results

[0136] Note: The mass proportions in Table 2 refer to the mass proportions of each main compound in the corresponding main composition.

[0137] It can be seen from the data in the above table that the device driving voltage of the single-body material device of device comparison example 3 is higher and the life is shorter; compared with the single-body device, the dual-body device of device comparison example 1 reduces the driving voltage of the device, but the efficiency and life of the device are reduced; although the device life of the dual-body device of device comparison example 2 is extended a little, the driving voltage and efficiency are not improved; and the device embodiments 1 to 5 provided by the present invention can not only significantly reduce the device driving voltage, but also significantly extend the device life.

[0138] Performance testing of composition examples In order to illustrate that the blue light-emitting host composition provided by the present invention has a good melting point advantage during the evaporation process, the melting points of the composition examples provided by the present invention were measured, and the DSC curves of some host compounds and compositions are shown in FIG. Figures 2 to 5 The measurement results are shown in Table 3.

[0139] Table 3

[0140] Note: The melting point test instrument is NETZSCH DSC 3500. The mass proportions of the host compounds in Examples 1 to 5 in the corresponding blue light-emitting host compositions are shown in Table 1.

[0141] from Figures 2 to 5 It can be read in sequence that the melting points of compound A-1 are 282°C, the melting point of compound B-1 is 290°C, and the melting point of compound C-1 is 282°C. The melting point of the composition obtained by mixing compounds A-1, B-1 and C-1 according to the proportions in Table 1 is 243°C. It can be seen that the melting point of the blue light-emitting host composition provided by the present invention is lower than the melting points of each monomer. The lower melting point is conducive to the composition provided by the present invention to form an organic thin film by evaporation at a constant component ratio.

[0142] Figure 6 This is the composition used in device comparative example 1. It can be seen from the figure that the comparative example composition does not form a single phase transition peak and has no fixed single melting point. The lack of a fixed single melting point may lead to poor component stability of the composition during the evaporation process.

[0143] Main composition film component consistency test To further illustrate the advantages of the blue light-emitting host composition provided by the present invention, a host composition film was formed from the composition example, and the compositional consistency of the film was tested. The host composition was premixed according to the premixing ratios (referring to the mass proportion of each host compound in the corresponding host composition) listed in Tables 4-1 to 4-3. The premixed host composition was then formed into a 2000 Å thick film at different evaporation rates. The above operation was repeated three times (i.e., the same composition was evaporated three times at the same premixing ratio). The mass proportion of each compound in the film was determined by high performance liquid chromatography on the three formed films. The evaluation results are as follows: Table 4-1

[0144] Table 4-2

[0145] Table 4-3

[0146] It can be seen from the above table that at evaporation rates of 0.5Å / s, 1Å / s and 3Å / s, respectively, compared with comparative effect examples 1-1 to 1-9 composed of a two-component mixed main material, the mass ratio of each compound in effect examples 1-1 to 2-9 composed of the blue light-emitting main composition provided by the present invention in the final evaporated film is relatively constant under continuous working conditions, and is slightly different from the initial pre-mixed ratio.

[0147] At a low evaporation rate of 0.5Å / s, in comparative examples 1-1 to 1-3, under continuous working conditions, the mass ratio of each compound in the final evaporated film is significantly different from the initial premixed ratio. The ratio of the evaporated components is not in accordance with the premixed ratio, which will have an adverse effect on device performance. As the evaporation rate increases, although the mass ratio of each compound in the comparative example composed of the two-component mixed main material in the final film after evaporation is closer to the initial premixed ratio, the mass ratio of each compound in the two-component mixed main material in the final film after evaporation under continuous working conditions fluctuates greatly. At a evaporation rate of 3Å / s, it can be seen that the fluctuation of the two-component mixed main materials of comparative examples 1-7 to 1-9 is significantly increased, while the blue-light-emitting main composition of effect examples 1-7 to 2-9 provided by the present invention maintains good process stability and component ratio constancy at different evaporation rates, indicating that by using the blue-light-emitting main composition provided by the present invention, it is possible to maintain good component ratio constancy under different production processes and continuous operating conditions. However, in the comparative example composed of the two-component mixed main material, the mass ratio of each compound in the final film after evaporation under different evaporation rates and continuous operating conditions is quite different from the initial premixed ratio, which is likely to cause the components of the evaporated organic film layer to fail to be composed according to the premixed ratio, resulting in the inability to stably exert the premixing advantage.

[0148] Device performance stability test According to the above process, the composition used in comparative example 1-1 was continuously prepared into device comparison examples 1-1 to 1-3 under the same working conditions, and the blue light-emitting main composition of the present invention's effect example 1-1 was continuously prepared into device embodiments 1-1 to 1-3 under the same working conditions. The device performance was tested under the same test conditions according to Table 2, and the results are shown in Table 5.

[0149] Table 5

[0150] Note: The mass proportions in Table 5 refer to the mass proportions of each main compound in the corresponding main composition.

[0151] As can be seen from the above table, the voltage efficiency and life of the device embodiments 1-1 to 1-3 provided by the present invention are relatively stable, and are both better than the device comparative example. As can be seen from Table 5, the device performance of the device comparative examples 1-1 to 1-3 has obvious volatility, which may be due to the fact that the compositions of comparative examples 1-1 to 1-3 have no fixed melting point, resulting in poor component constancy of the composition during the evaporation process, and the mass ratio of each compound in the film after the final evaporation is quite different from the initial premixing ratio, which causes the device performance of the device comparative example to fluctuate greatly. The melting point of the blue light-emitting host composition provided by the present invention is lower than the melting point of each monomer, and the lower melting point is conducive to the composition provided by the present invention to form an organic thin film by evaporation with a constant component ratio. Therefore, the device performance of the device embodiment provided by the present invention prepared under continuous working conditions is more stable, which shows that the present invention is more suitable for commercial mass production.

[0152] 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 scope of protection of the present invention.

Claims

1. A blue light-emitting host composition, characterized in that At least comprising a first host compound, a second host compound and a third host compound; the structure of the first host compound is shown in Formula I, the structure of the second host compound is shown in Formula II, and the structure of the third host compound is shown in Formula I or Formula II; The first host compound, the second host compound and the third host compound are different from each other; AND, II; wherein Ar1 and Ar2 are each independently selected from any one or a combination of any two of a deuterated or non-deuterated aryl group having 6 to 30 carbon atoms, a deuterated or non-deuterated fused ring aryl group having 10 to 30 carbon atoms; Ar3 is selected from any one or a combination of any two of a deuterated or non-deuterated aryl group having 6 to 30 carbon atoms, a deuterated or non-deuterated fused ring aryl group having 10 to 30 carbon atoms; Ar4 is selected from any one or a combination of any two of a deuterated or non-deuterated heterocyclic group having 5 to 30 carbon atoms and containing an oxygen atom, and a deuterated or non-deuterated fused-ring heterocyclic group having 5 to 30 carbon atoms and containing an oxygen atom; L1, L2, L3, and L4 are each independently selected from any one of a single bond, a deuterated or non-deuterated aromatic group having 6 to 30 carbon atoms; The mass proportion of any one host compound in the blue light-emitting host composition is between 10 and 80 wt %.

2. The blue light-emitting host composition according to claim 1, characterized in that Ar1 and Ar2 are each independently selected from any one or a combination of any two of deuterated or non-deuterated phenyl, deuterated or non-deuterated biphenyl, deuterated or non-deuterated naphthyl, and deuterated or non-deuterated phenanthrenyl; Ar3 is selected from any one or a combination of any two of deuterated or non-deuterated phenyl, deuterated or non-deuterated biphenyl, and deuterated or non-deuterated naphthyl; Ar4 is selected from 、 、 、 Any of the following, any hydrogen in Ar4 can be replaced by deuterium; L1, L2, L3, and L4 are each independently selected from any one of a single bond, a deuterated or non-deuterated phenyl group, and a deuterated or non-deuterated biphenyl group; When the third host compound is selected from the structure shown in Formula I, in the blue light-emitting host composition, the mass ratio of the first host compound, the second host compound and the third host compound is 0.1-6:0.5-7:1; When the third host compound is selected from the structure shown in Formula II, in the blue light-emitting host composition, the mass ratio of the first host compound, the second host compound and the third host compound is 0.5~7:0.1~6:

1.

3. The blue light-emitting host composition according to claim 1, characterized in that The difference in molecular weight between any two of the first host compound, the second host compound and the third host compound is within 100.

4. The blue light-emitting host composition according to claim 1, characterized in that When the first host compound, the second host compound and the third host compound are deuterated compounds, the deuteration rate of each deuterated site in their structure is greater than 5%.

5. The blue light-emitting host composition according to claim 1, characterized in that Formula I is selected from one of the structures shown below: ； Wherein, Dn represents that n hydrogens are replaced by deuterium, and n is a positive integer ranging from 1 to the maximum deuterium generation number.

6. The blue light-emitting host composition according to claim 1, characterized in that Formula II is selected from one of the structures shown below: ； Wherein, Dn represents that n hydrogens are replaced by deuterium, and n is a positive integer ranging from 1 to the maximum deuterium generation number.

7. The blue light-emitting host composition according to any one of claims 1 to 4, characterized in that: The blue light-emitting host composition is selected from any one of the following: Composition 1: Composition 2: Composition 3: Composition 4: Composition 5: Composition 6: Composition 7: Composition 8: Composition 9: Composition 10: Composition 11: Composition 12: Composition 13: Composition 14: Composition 15: Composition 16: Composition 17: Composition 18: Composition 19: Composition 20: Composition 21: Composition 22: Composition 23: Composition 24: Composition 25: Composition 26: Composition 27: Composition 28: Composition 29: ； In each composition, compound A-1 to compound A-29 are first main compounds, compound B-1 to compound B-29 are second main compounds, and compound C-1 to compound C-29 are third main compounds.

8. An organic electroluminescent device, characterized in that: The invention comprises an anode, a hole transport region, a light-emitting layer, an electron transport region and a cathode which are sequentially arranged on a substrate; wherein the light-emitting layer comprises the blue light-emitting host composition according to any one of claims 1 to 7.

9. The organic electroluminescent device according to claim 8, characterized in that: The light-emitting layer includes a host material and a guest material, wherein the host material includes the blue light-emitting host composition according to any one of claims 1 to 7.

10. A display device, characterized in that The organic electroluminescent device according to claim 8 or 9.

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