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

Abstract

The invention discloses a blue light-emitting main body composition and an organic electroluminescent 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 first host compound, the second host compound, and the third host compound are different from each other. When the blue light-emitting main body composition provided by the invention is used as a light-emitting layer main body material to be applied to a blue organic light-emitting device, the driving voltage of the device can be obviously reduced, the service life of the device can be obviously prolonged, and the service life of the device can be obviously prolonged under continuous working conditions. The organic light-emitting device prepared from the blue light-emitting main body composition provided by the invention is relatively stable in voltage efficiency and service life. I, II

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of OLED, and specifically comprises a blue light-emitting host composition and an organic electroluminescent device comprising the same. BACKGROUND

[0002] As a promising semiconductor light-emitting technology, organic electroluminescent devices (OLEDs) have made remarkable research progress in material science, device structure, performance optimization and industrial application in recent years. How to further improve the comprehensive performance of blue organic electroluminescent devices is a hot research issue at present.

[0003] The existing pre-mixed double-host blue fluorescent light-emitting device has obvious advantages. The double-host material realizes good carrier balance by optimizing the energy level matching, which not only reduces the driving voltage and improves the luminous efficiency, but also effectively suppresses the efficiency roll-off. In the preparation of the pre-mixed double-host blue fluorescent light-emitting device, the two host materials are usually pre-mixed in a preset mass ratio before evaporation, and then evaporated in one evaporation source. However, in the evaporation process, the two host components in the pre-mixed material do not evaporate according to the pre-mixed ratio, resulting in a large difference between the actual obtained evaporation film layer and the initial preset ratio of the two host materials, which further leads to a decrease in the service life and needs to be further optimized. Moreover, the ratio of the two host materials at different evaporation speeds is also difficult to maintain constant, which leads to fluctuations in device performance when the evaporation speed changes, poor stability, and greatly affects the production of the device under continuous working conditions. SUMMARY

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

[0005] To achieve the above purpose, the technical solution adopted by the present application comprises: The first aspect of the present application provides a blue light-emitting host composition, comprising at least three different compounds: a first host compound, a second host compound and a third host compound; the structure of the first host compound is shown as formula I, the structure of the second host compound is shown as formula II, and the third host compound is selected from the structures shown as formula I or formula II; the first host compound, the second host compound and the third host compound are not the same as each other; I, II; wherein Ar1, Ar3 are each independently selected from any one or a combination of any two of deuterated or non-deuterated aryl with carbon number of 6 to 30, deuterated or non-deuterated condensed ring aryl with carbon number of 10 to 30; Ar2 is selected from substituted or unsubstituted dibenzofuranyl; when Ar2 is substituted, the substituent is selected from deuterium, any one or a combination of two of aryl groups having a carbon number of 6 to 30; Ar4 is selected from any one of , , , , any one hydrogen in Ar4 can be substituted with deuterium; L1, L2, L3, L4 are each independently selected from any one of a single bond, deuterated or non-deuterated phenyl, deuterated or non-deuterated biphenyl; The mass percentage of any one compound in the blue light-emitting host composition is between 10-80 wt%.

[0006] Further, Ar1, Ar3 are each independently selected from any one or a combination of two of deuterated or non-deuterated aryl groups having a carbon number of 6 to 20, deuterated or non-deuterated condensed ring aryl groups having a carbon number of 10 to 20.

[0007] Further, L1, L2, L3, L4 are each independently selected from any one of a single bond, deuterated or non-deuterated phenyl, deuterated or non-deuterated biphenyl.

[0008] Further, the mass percentage of any one compound in the blue light-emitting host composition is between 10-75 wt%.

[0009] Further, the mass percentage of any one compound in the blue light-emitting host composition is between 10-70 wt%.

[0010] Further, the mass percentage of any one compound in the blue light-emitting host composition is between 10-65 wt%.

[0011] Further, the mass percentage of any one compound in the blue light-emitting host composition is between 10-60 wt%.

[0012] Further, the total mass of the compounds selected from Formula I in the blue light-emitting host composition is not less than 10 wt% of the mass of the blue light-emitting host composition.

[0013] Further, the total mass of the compounds selected from Formula I in the blue light-emitting host composition is not less than 20 wt% of the mass of the blue light-emitting host composition.

[0014] Further, the total mass of the compounds selected from Formula I in the blue light-emitting host composition is not less than 30 wt% of the mass of the blue light-emitting host composition.

[0015] Further, the total mass of the compound selected from Formula I in the blue light-emitting host composition accounts for not less than 40 wt% of the mass of the blue light-emitting host composition.

[0016] Further, the total mass of the compound selected from Formula II in the blue light-emitting host composition accounts for not less than 10 wt% of the mass of the blue light-emitting host composition.

[0017] Further, the total mass of the compound selected from Formula II in the blue light-emitting host composition accounts for not less than 20 wt% of the mass of the blue light-emitting host composition.

[0018] Further, the total mass of the compound selected from Formula II in the blue light-emitting host composition accounts for not less than 30 wt% of the mass of the blue light-emitting host composition.

[0019] Further, the total mass of the compound selected from Formula II in the blue light-emitting host composition accounts for not less than 40 wt% of the mass of the blue light-emitting host composition.

[0020] In combination with the first aspect, the ratio of the total mass of the compound selected from Formula I to the total mass of the compound selected from Formula II in the blue light-emitting host composition is 1:9~9:1.

[0021] Further, the ratio of the total mass of the compound selected from Formula I to the total mass of the compound selected from Formula II in the blue light-emitting host composition is 2:8~8:2.

[0022] Further, the ratio of the total mass of the compound selected from Formula I to the total mass of the compound selected from Formula II in the blue light-emitting host composition is 3:7~7:3.

[0023] Further, the ratio of the total mass of the compound selected from Formula I to the total mass of the compound selected from Formula II in the blue light-emitting host composition is 4:6~6:4.

[0024] When the third host compound is selected from the structure shown in Formula I, the mass ratio of the first host compound, the second host compound and the third host compound in the blue light-emitting host composition is 0.1~7:0.2~8:1; When the third host compound is selected from the structure shown in Formula II, the mass ratio of the first host compound, the second host compound and the third host compound in the blue light-emitting host composition is 0.2~8:0.1~7:1.

[0025] In combination with the first aspect, Ar2 is selected from or Any hydrogen in Ar2 can be replaced by deuterium.

[0026] In connection with the first aspect, Ar2is selected from any one of , , , , any hydrogen in Ar2may be replaced by deuterium.

[0027] In connection with the first aspect, Ar1, Ar3are each independently selected from any one of or a combination of any two of deuterated or non-deuterated phenyl, deuterated or non-deuterated biphenyl, deuterated or non-deuterated naphthyl, deuterated or non-deuterated phenanthryl.

[0028] In connection with the first aspect, the difference between the molecular weight of any two of the first host compound, the second host compound and the third host compound is within 100, i.e. the difference between the molecular weight of the first host compound and the second host compound is within 100, the difference between the molecular weight of the first host compound and the third host compound is within 100, the difference between the molecular weight of the second host compound and the third host compound is within 100.

[0029] In connection 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 the structure is > 5%.

[0030] Further, formula I is selected from the following structures:

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038] ; 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.

[0039] by To illustrate, it can represent When any hydrogen is replaced by deuterium, e.g. 、 、 、 wait.

[0040] In combination with the first aspect, Formula II is selected from the structure shown below:

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053] ; 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.

[0054] Further, the blue light emitting host composition is selected from any one of the following: Composition 1:

[0055] Composition 2:

[0056] Composition 3:

[0057] Composition 4:

[0058] Composition 5:

[0059] Composition 6:

[0060] Composition 7:

[0061] Composition 8:

[0062] Composition 9:

[0063] Composition 10:

[0064] Composition 11:

[0065] Composition 12:

[0066] Composition 13:

[0067] Composition 14:

[0068] Composition 15:

[0069] Composition 16:

[0070] Composition 17:

[0071] Composition 18:

[0072] Composition 19:

[0073] Composition 20:

[0074] Composition 21:

[0075] Composition 22:

[0076] Composition 23:

[0077] Composition 24:

[0078] Composition 25:

[0079] Composition 26:

[0080] Composition 27:

[0081] Composition 28:

[0082] Composition 29: ; The compound A-1 to compound A-29 in the composition is a first host compound, the compound B-1 to compound B-29 is a second host compound, and the compound C-1 to compound C-29 is a third host compound.

[0083] A second aspect of the present application provides an organic electroluminescence device, comprising an anode, a hole transport zone, a light-emitting layer, an electron transport zone, and a cathode sequentially arranged on a substrate; wherein the light-emitting layer comprises the blue light-emitting host composition as described above.

[0084] Further, the light-emitting layer comprises a host material and a guest material, wherein the host material comprises the blue light-emitting host composition as described above.

[0085] The present application has the following advantages: The blue light-emitting host composition disclosed in the present application comprises at least three different compounds, i.e. a first host compound, a second host compound and a third host compound. By combining the composition protected in the present application within a limited mass ratio range, the melting point of the obtained blue light-emitting host composition is lower than that of each single compound, and the lower melting point is conducive to the organic thin film formed by evaporation of the composition provided in the present application at a constant component ratio. Secondly, the blue light-emitting host compound provided in the present application is evaporated to form a host composition thin film under continuous working conditions and different evaporation rates, and the mass ratio of the three compounds in the finally obtained thin film after evaporation is relatively constant, and is relatively close to the ratio of the initial pre-mixing, and has high stability. The blue light-emitting host composition provided in the present application is applied to a blue organic electroluminescent device as a light-emitting layer host material. The blue light-emitting host composition provided in the present application can not only significantly reduce the driving voltage of the device, but also significantly prolong the service life of the device, and under continuous working conditions, the voltage efficiency and the service life of the organic electroluminescent device prepared from the blue light-emitting host composition provided in the present application are relatively stable, which indicates that the blue light-emitting host composition provided in the present application is more likely to obtain an organic electroluminescent device with excellent performance and stability. BRIEF DESCRIPTION OF DRAWINGS

[0086] Figure 1 It is a structural schematic diagram of the organic electroluminescent device of the present application, wherein 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, 5 is a light-emitting auxiliary layer, 6 is a light-emitting layer, 7 is a hole blocking layer, 8 is an electron transport layer, 9 is an electron injection layer, 10 is a cathode, and 11 is a cover layer.

[0087] Figure 2 It is a DSC curve of compound A-1.

[0088] Figure 3 It is a DSC curve of compound B-1.

[0089] Figure 4 It is a DSC curve of compound C-1.

[0090] Figure 5 It is a DSC curve of a composition mixed by compound A-1, B-1 and C-1 in a mass ratio of 5:3:2.

[0091] Figure 6 It is a DSC curve of a composition mixed by compound A-1 and B-1 in a mass ratio of 5:5. DETAILED DESCRIPTION

[0092] In order to more clearly understand the content of the present application, the embodiments will be described in detail in combination with the drawings.

[0093] The compounds of the present application are suitable for use in light-emitting elements, display panels and electronic devices, in particular in organic electroluminescent devices. The electronic devices according to the present application are devices comprising at least one layer of an organic compound, which devices can also comprise layers of inorganic materials or be formed entirely from inorganic materials. The electronic devices are preferably organic electroluminescent devices (OLEDs), organic integrated circuits (O-ICs), organic field-effect transistors (O-FETs), organic thin-film transistors (O-TFTs), organic light-emitting transistors (O-LETs), organic solar cells (O-SCs), organic dye-sensitised solar cells (O-DSSCs), organic optical detectors, organic photoreceptors, organic field-quench devices (O-FQDs), light-emitting electrochemical cells (LECs), organic laser diodes (O-lasers) and organic plasmonic devices. The electronic devices are preferably organic electroluminescent devices (OLEDs). A schematic structural diagram of an exemplary organic electroluminescent device is shown in Figure 1

[0094] The present application also relates to the use of the described compositions as coating materials or printing inks in the production of organic electronic devices, particularly preferred is the production method by printing or coating.

[0095] Suitable printing or coating techniques can include, but are not limited to, inkjet printing, inkjet printing, letterpress printing, screen printing, dip coating, spin coating, blade coating, roller printing, reverse-roller printing, offset lithography printing, flexographic printing, rotogravure printing, spray coating, brush coating or pad printing, inkjet printing, slot-die coating and the like. Inkjet printing, slot-die coating, inkjet printing and gravure printing are preferred.

[0096] Experimental Section In order to more clearly understand the present application, the polycyclic compounds, the preparation method of the compounds and the light-emitting properties of the device will be explained in detail with examples. Various chemical reactions can be applied to the synthesis method of the compounds of one embodiment of the present application. However, it should be noted that the synthesis method of the compounds of one embodiment of the present application is not limited to the synthesis methods described below. Unless otherwise indicated, the following syntheses are carried out under an atmosphere of an inert gas in anhydrous solvents. Solvents and reagents can be purchased from conventional reagent suppliers.

[0097] The compounds used in the following compositions can be purchased and synthesized by oneself.

[0098] Composition Example 1 This example provides a blue light-emitting host composition consisting of compound A-1, compound B-1 and compound C-1, the mass ratio of each compound is shown in Table 1: ; Composition Example 2​ The present embodiment provides a blue light-emitting host composition consisting of compound A-2, compound B-2 and compound C-2, the mass ratio of each compound being as shown in Table 1: ; Composition Example 3 The present embodiment provides a blue light-emitting host composition consisting of compound A-3, compound B-3 and compound C-3, the mass ratio of each compound being as shown in Table 1: ; Composition Example 4 The present embodiment provides a blue light-emitting host composition consisting of compound A-4, compound B-4 and compound C-4, the mass ratio of each compound being as shown in Table 1: ; Composition Example 5 The present embodiment provides a blue light-emitting host composition consisting of compound A-5, compound B-5 and compound C-5, the mass ratio of each compound being as shown in Table 1: ; Composition Example 6 The present embodiment provides a blue light-emitting host composition consisting of compound A-6, compound B-6 and compound C-6, the mass ratio of each compound being as shown in Table 1: ; Composition Example 7 The present embodiment provides a blue light-emitting host composition consisting of compound A-7, compound B-7 and compound C-7, the mass ratio of each compound being as shown in Table 1: ; Composition Example 8 The present embodiment provides a blue light-emitting host composition consisting of compound A-8, compound B-8 and compound C-8, the mass ratio of each compound being as shown in Table 1: ; Composition Example 9 The present embodiment provides a blue light-emitting host composition consisting of compound A-9, compound B-9 and compound C-9, the mass ratio of each compound being as shown in Table 1: ; Composition Example 10 This example provides a blue light-emitting host composition consisting of compound A-10, compound B-10, and compound C-10, the mass ratio of each compound being as shown in Table 1: ; Composition Example 11 This example provides a blue light-emitting host composition consisting of compound A-11, compound B-11, and compound C-11, the mass ratio of each compound being as shown in Table 1: ; Composition Example 12 This example provides a blue light-emitting host composition consisting of compound A-12, compound B-12, and compound C-12, the mass ratio of each compound being as shown in Table 1: ; Composition Example 13 This example provides a blue light-emitting host composition consisting of compound A-13, compound B-13, and compound C-13, the mass ratio of each compound being as shown in Table 1: ; Composition Example 14 This example provides a blue light-emitting host composition consisting of compound A-14, compound B-14, and compound C-14, the mass ratio of each compound being as shown in Table 1: ; Composition Example 15 This example provides a blue light-emitting host composition consisting of compound A-15, compound B-15, and compound C-15, the mass ratio of each compound being as shown in Table 1: ; Composition Example 16 This example provides a blue light-emitting host composition consisting of compound A-16, compound B-16, and compound C-16, the mass ratio of each compound being as shown in Table 1: ; Composition Example 17 The embodiment provides a blue light-emitting host composition, which is composed of compound A-17, compound B-17 and compound C-17, and the mass proportion of each compound is shown in Table 1. ; Composition embodiment 18 The embodiment provides a blue light-emitting host composition, which is composed of compound A-18, compound B-18 and compound C-18, and the mass proportion of each compound is shown in Table 1. ; Composition embodiment 19 The embodiment provides a blue light-emitting host composition, which is composed of compound A-19, compound B-19 and compound C-19, and the mass proportion of each compound is shown in Table 1. ; Composition embodiment 20 The embodiment provides a blue light-emitting host composition, which is composed of compound A-20, compound B-20 and compound C-20, and the mass proportion of each compound is shown in Table 1. ; Composition embodiment 21 The embodiment provides a blue light-emitting host composition, which is composed of compound A-21, compound B-21 and compound C-21, and the mass proportion of each compound is shown in Table 1. ; Composition embodiment 22 The embodiment provides a blue light-emitting host composition, which is composed of compound A-22, compound B-22 and compound C-22, and the mass proportion of each compound is shown in Table 1. ; Composition embodiment 23 The embodiment provides a blue light-emitting host composition, which is composed of compound A-23, compound B-23 and compound C-23, and the mass proportion of each compound is shown in Table 1. ; Composition embodiment 24 The embodiment provides a blue light-emitting host composition, which is composed of compound A-24, compound B-24 and compound C-24, and the mass proportion of each compound is shown in Table 1. ; Composition Example 25 The present example provides a blue light-emitting host composition consisting of compound A-25, compound B-25 and compound C-25, the mass ratio of each compound being as shown in Table 1: ; Composition Example 26 The present example provides a blue light-emitting host composition consisting of compound A-26, compound B-26 and compound C-26, the mass ratio of each compound being as shown in Table 1:

[0099] Composition Example 27 The present example provides a blue light-emitting host composition consisting of compound A-27, compound B-27 and compound C-27, the mass ratio of each compound being as shown in Table 1: ; Composition Example 28 The present example provides a blue light-emitting host composition consisting of compound A-28, compound B-28 and compound C-28, the mass ratio of each compound being as shown in Table 1: ; Composition Example 29 The present example provides a blue light-emitting host composition consisting of compound A-29, compound B-29 and compound C-29, the mass ratio of each compound being as shown in Table 1: ; Table 1

[0100] Note: The mass ratio in Table 1 refers to the mass ratio of each host compound in the corresponding blue light-emitting host composition.

[0101] Manufacture and characterization of OLEDs Device Example The organic electroluminescent device provided by the present application comprises an anode, a hole transport zone, a light-emitting layer, an electron transport zone and a cathode which are sequentially arranged on a substrate. Further, the hole transport zone comprises a hole injection layer, a hole transport layer and a light-emitting auxiliary layer; and the electron transport zone comprises an electron transport layer and an electron injection layer.

[0102] Further, 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 kind of molecular material or multiple kinds of molecular materials.

[0103] The composition of the present application can be used in the light-emitting layer of the organic electroluminescent device as described above.

[0104] The anode in the embodiment is made of the anode material commonly used in the art, such as ITO, Ag or a multi-layer structure thereof. The hole injection layer is made of the hole injection material commonly used in the art, and is doped with F4TCNQ, HATCN, NDP-9, etc. The hole transport layer is made of the hole transport material commonly used in the art. The light-emitting layer is made of the host / guest material composition provided in the present application. The electron transport layer is made of the electron transport material commonly used in the art. The electron injection layer is made of the electron injection material commonly used in the art, such as LiQ, LiF, Yb, etc. The cathode is made of the material commonly used in the art, such as metal Al, Ag or a metal mixture (Ag-doped Mg, Ag-doped Ca, etc.).

[0105] The electrode preparation method and the deposition method of each functional layer in the embodiment are the conventional methods in the art, such as vacuum thermal evaporation or inkjet printing, which will not be described here again. Only some process details in the preparation process and test methods are described as follows: Device embodiment 1 The substrate used in the present application is subjected to the following operations: after the ITO substrate is patterned to have a light-emitting area with a size of 3 mm x 3 mm, it is subjected to water / isopropanol ultrasonic treatment, UV / ozone irradiation, and then 100°C drying. After that, the ITO substrate is installed on the substrate support of a vacuum deposition device and the pressure is adjusted to make the vacuum rate 1 x 10 -7torr. Then, a hole injection layer was formed by vacuum depositing compound HT01 and compound PD01 (mass ratio of compound HT01 to compound PD01 was 97:3) on the ITO layer (anode) of the substrate at a thickness of 10 nm, a hole transport layer was formed by vacuum depositing compound HT01 on the hole injection layer at a thickness of 100 nm, a light-emitting auxiliary layer was formed by vacuum depositing compound BP01 on the hole transport layer at a thickness of 5 nm, a light-emitting layer was formed by vacuum depositing a mixture of the composition provided in Embodiment 1 of the present application and compound BD01 on the light-emitting auxiliary layer at a thickness of 20 nm, wherein the composition in Embodiment 1 of the present application served as a host material and compound BD01 served as a guest material, and the mass ratio of the composition in Embodiment 1 of the present application to the guest material was 98:2, a hole blocking layer was formed by vacuum depositing compound HB01 on the light-emitting layer at a thickness of 5 nm, an electron transport layer was formed by vacuum depositing compound ET01 and compound LiQ (mass ratio of compound ET01 to compound LiQ was 1:1) on the hole blocking layer at a thickness of 30 nm, an electron injection layer was formed by vacuum depositing Yb on the electron transport layer at a thickness of 1 nm, a cathode was formed by depositing Mg and Ag (mass ratio of Mg to Ag was 1:9) on the electron injection layer at a thickness of 15 nm, and a cover layer was formed by depositing compound CP01 on the cathode at a thickness of 50 nm. Finally, the substrate on which the deposition was completed was encapsulated, a coating device was used to perform a coating process on the cleaned cover plate with UV glue, the cover plate coated in this way was moved to a pressing section, the substrate on which the deposition was completed was placed on the upper end of the cover plate, and the substrate and the cover plate were laminated under the action of a laminating device, and at the same time, the UV glue was subjected to light curing, thereby preparing a top-emission organic electroluminescent device. The structure of the device is shown in Figure 1 .

[0106] In addition to the host and guest materials of the light-emitting layer, the molecular structures of the materials of the other layers are as follows:

[0107]

[0108]

[0109] Device embodiments 2-5 The above method was used to prepare organic electroluminescent devices by taking the compositions provided in Embodiments 2-5 of the present application as host materials, thereby obtaining device embodiments 2-5.

[0110] Device comparative examples 1-4 The above method was used to prepare organic electroluminescent devices by taking the host compositions in Table 2 as host materials, and the specific composition combinations are shown in Table 2, thereby obtaining device comparative examples 1-4.

[0111] The OLED devices described above were tested by standard methods. To this end, the driving voltage, luminous efficiency of the organic electroluminescent device were determined at a current density of J = 10 mA / cm 2 The LT97 indicates that the luminous intensity of the prepared blue light device decreases to 97% of its initial value L0 after a time LT97 when the device is operated at J = 20 mA / cm 2

[0112] The test instruments and methods for performance testing of the above-mentioned example, comparative OLED devices are as follows: Luminous efficiency C.E (cd / A), color coordinates (CIEy) were tested using a spectral scanner PhotoResearch PR-635; Current density and turn-on voltage: tested using a digital source meter Keithley 2400; The luminous efficiency of the blue light device is greatly affected by the chromaticity, and the industry generally uses BI value as the basis for the efficiency of the blue light device, BI (Blue index) is obtained by dividing the luminous efficiency C.E (cd / A) by the color coordinates (CIEy); Lifetime test: silicon photovoltaic OLED device lifetime test system was used.

[0113] The performance test results of the above-mentioned devices are listed in Table 2.

[0114] Table 2 Blue light device performance test results

[0115] Note: The mass ratio in Table 2 refers to the mass ratio of each host compound in the corresponding host composition.

[0116] From the above data, it can be seen that the single host material device of device comparative example 4 has a higher driving voltage, and the efficiency and lifetime are obviously lower; compared with the single host device, the double host devices of device comparative example 1 and device comparative example 3 have a small increase in efficiency and lifetime, but the driving voltage of the device is significantly increased, the double host device of device comparative example 2 has a certain extension of the device lifetime, but the driving voltage and efficiency of the device are not obviously improved; and the device examples 1 to 5 provided by the present application not only significantly improve the efficiency of the device, prolong the lifetime of the device, but also appropriately reduce the driving voltage of the device.

[0117] Performance test of composition examples In order to illustrate that the blue light host composition provided by the present application has good melting point advantage in the evaporation process, the melting point of the composition examples provided by the present application was measured, and the DSC curves of some components and compositions are shown in Figures 2 to 5 ​The test results are shown in Table 3.

[0118] Table 3

[0119] Note: The melting point testing instrument is NETZSCH DSC 3500, and the mass ratio of each host compound in Examples 1 to 5 and Comparative Examples 1 to 4 in the corresponding blue light-emitting host composition is shown in Table 2.

[0120] From the test data in Table 3, it can be seen that the melting point of the blue light-emitting host composition provided by the present application is fixed and is lower than that of each single body. The composition of Comparative Example 1 and Comparative Example 3 does not have a single fixed melting point. The melting points of the two single bodies in the composition of Comparative Example 2 are both 294℃, and the melting point of the composition is also 294℃. The melting point of the composition of Comparative Example 2 cannot be lower than that of each single body. The melting point of the blue light-emitting host composition provided by the present application is fixed and is lower than that of each single body, which is beneficial to the composition provided by the present application to form an organic thin film by evaporation with constant component ratio.

[0121] From Figures 2 to 5 The melting point of compound A-1 is 294℃, the melting point of compound B-1 is 290℃, and the melting point of compound C-1 is 294℃. The melting point of the composition mixed from compounds A-1, B-1 and C-1 according to the ratio in Table 2 is 252℃. It can be seen from this that the melting point of the blue light-emitting host composition of Example 1 provided by the present application is lower than that of each single body. A lower melting point is beneficial to the composition provided by the present application to form an organic thin film by evaporation with constant component ratio.

[0122] Figure 6 The composition used in Device Comparative Example 1. It can be seen from the figure that the composition of the comparative example does not form a single phase change peak, and does not have a single fixed melting point. The lack of a single fixed melting point may result in poor component constancy of the composition during evaporation.

[0123] Host composition thin film component constancy test In order to further illustrate the advantages of the blue light-emitting host composition provided by the present application, the composition example is formed into a host composition thin film, and the component constancy of the thin film is tested. The host composition is premixed according to the premixing ratio (referring to the mass ratio of each host compound in the corresponding host composition) in Table 4-1 to Table 4-3, and then the premixed host composition is formed into a thin film with a thickness of 2000Å at different evaporation rates. The above operation is repeated three times in succession (i.e. the same composition is continuously evaporated three times to form a thin film at the same premixing ratio). The mass ratio of each compound in the formed three thin films is determined by high performance liquid chromatography analysis method, and the evaluation results are as follows: Table 4-1

[0124] Table 4-2

[0125] Table 4-3

[0126] As can be seen from Tables 4-1 to 4-3, at the deposition rates of 0.5 Å / s, 1 Å / s and 3 Å / s respectively, compared with the comparative effect examples 1-1 to 1-9 composed of two-component mixed host materials, the mass proportions of each compound in the thin film after final deposition in the effect examples 1-1 to 2-9 composed of the blue light-emitting host composition provided by the application are relatively constant under continuous operation conditions, and the difference with the initial premixing proportion is small.

[0127] At the low deposition rate of 0.5 Å / s, the mass proportions of each compound in the thin film after final deposition of the comparative effect examples 1-1 to 1-3 under continuous operation conditions have a large difference with the initial premixing proportion, and the deposition component proportion does not have an adverse effect on the device performance according to the premixing proportion. With the increase of the deposition rate, although the mass proportions of each compound in the thin film after final deposition of the comparative effect examples composed of two-component mixed host materials are closer to the initial premixing proportion, the mass proportions of each compound in the thin film after final deposition of the two-component mixed host materials under continuous operation conditions have a large fluctuation, and at the deposition rate of 3 Å / s, it can be seen that the fluctuation of the two-component mixed host materials of the comparative effect examples 1-7 to 1-9 is obviously increased, while the blue light-emitting host compositions of the effect examples 1-7 to 2-9 provided by the application maintain good process stability and component proportion constancy under different deposition rates, indicating that by using the blue light-emitting host composition provided by the application, good component proportion constancy can be maintained under different production processes and continuous operation conditions, while the mass proportions of each compound in the thin film after final deposition of the comparative effect examples composed of two-component mixed host materials under different deposition rates and continuous operation conditions have a large difference with the initial premixing proportion, which is likely to result in that the deposited organic film layer components cannot be composed according to the premixing proportion, and the premixing advantage cannot be stably played.

[0128] Device performance constancy test According to the above process, the double-host composition used in the comparative effect example 1-1 is continuously prepared into device comparative examples 1-1 to 1-3 under the same conditions, the blue light-emitting host composition of the effect example 1-1 of the application is continuously prepared into device examples 1-1 to 1-3 under the same conditions, and the device performance is tested under the same test conditions according to Table 2, and the results are shown in Table 5.

[0129] Table 5

[0130] Note: The mass ratio in Table 5 refers to the mass ratio of each host compound in the corresponding host composition.

[0131] As can be seen from the above table, the voltage efficiency and lifetime of the device embodiments 1-1 to 1-3 provided by the present application are more stable, and are all better than the device comparative examples. As can also be seen from Table 5, the device performance of the device comparative examples 1-1 to 1-3 has obvious fluctuation, which may be due to the fact that the composition of the comparative examples 1-1 to 1-3 has no fixed melting point, resulting in poor constant of the composition during evaporation process, the mass ratio of each compound in the thin film after final evaporation is greatly different from the initial premixed ratio, which makes the device performance of the device comparative examples have large fluctuation, while the melting point of the blue light emitting host composition provided by the present application is lower than that of each single compound, and the lower melting point is conducive to the evaporation of the composition provided by the present application to form an organic thin film with constant component ratio, therefore the device performance of the device prepared under continuous working condition is more stable, which shows that the present application is more suitable for commercial mass production.

[0132] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application, and for those skilled in the art, other different forms of changes or variations can be made on the basis of the above description, and it is impossible to enumerate all the embodiments here, and any obvious changes or variations derived from the technical solutions of the present application still fall within the protection scope of the present application.

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 Ar3 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; Ar2 is selected from substituted or unsubstituted dibenzofuranyl; when Ar2 has a substituent, the substituent is selected from any one or a combination of two of deuterium and an aromatic group having 6 to 30 carbon atoms; 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 aromatic group having 6 to 30 carbon atoms; The mass proportion of any one 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 Ar2 is selected from or , any hydrogen in Ar2 can be replaced by deuterium.

3. The blue light-emitting host composition according to claim 1, characterized in that Ar1 and Ar3 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.

4. 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.

5. 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%.

6. The blue light-emitting host composition according to claim 1, characterized in that Formula I is selected from the following structures: ； 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 claim 1, characterized in that Formula II is selected from the following structures: ； 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.

8. The blue light-emitting host composition according to claim 1, 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 the 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.

9. 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 8.

10. The organic electroluminescent device according to claim 9, 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 8.

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