A blue light-emitting host composition and an organic electroluminescent device comprising the same

Abstract

The application discloses a blue light-emitting host composition and an organic electroluminescent device comprising the same. The blue light-emitting host composition comprises at least 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 structure of the third host compound is 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. The blue light-emitting host composition provided by the application is applied to a blue organic electroluminescent device as a light-emitting layer host material, which can obviously reduce the driving voltage of the device, significantly prolong the service life of the device, and the voltage efficiency and the service life of the organic electroluminescent device prepared from the blue light-emitting host composition provided by the application are relatively stable under continuous working conditions.I, II.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of OLEDs, 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 progress in recent years in terms of material science, device structure, performance optimization, and industrial application. How to further improve the comprehensive performance of blue organic electroluminescent devices is a hot research topic.

[0003] The existing pre-mixed double-host blue fluorescent light-emitting device has significant advantages. The double-host materials achieve good carrier balance through optimized energy level matching, which not only reduces the driving voltage and improves the luminous efficiency, but also effectively suppresses the efficiency roll-off. Currently, in the preparation of pre-mixed double-host blue fluorescent light-emitting devices, two host materials are usually pre-mixed in a preset mass ratio before evaporation, and then evaporated in one evaporation source. However, during the evaporation process, the two host components in the pre-mixed material do not evaporate in the pre-mixed ratio, resulting in a large difference between the actual evaporation film layer ratio of the two host materials and the initial preset ratio, which further leads to a decrease in the lifetime, 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 devices under continuous working conditions. SUMMARY

[0004] In view of the above problems existing in the prior art, the 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 application comprises:

[0006] The first aspect of the 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 in formula I, the structure of the second host compound is shown in formula II, and the third host compound is selected from the structures shown in 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;

[0007] I, II;

[0008] wherein Ar1, Ar3are each independently selected from any one or a combination of two of deuterated or non-deuterated aryl group having 6 to 30 carbon atoms, deuterated or non-deuterated condensed ring aryl group having 10 to 30 carbon atoms;

[0009] Ar2is selected from substituted or unsubstituted dibenzofuranyl; when Ar2is substituted, the substituent is selected from any one or a combination of two of deuterium, aryl group having 6 to 30 carbon atoms;

[0010] Ar4is selected from any one of 、 、 、 , any hydrogen in Ar4may be substituted with deuterium;

[0011] L1, L2, L3, L4are each independently selected from any one of single bond, deuterated or non-deuterated phenyl group, deuterated or non-deuterated biphenyl group;

[0012] The mass percentage of any one compound in the blue light emitting host composition is between 10 to 80 wt%.

[0013] Further, Ar1, Ar3are each independently selected from any one or a combination of two of deuterated or non-deuterated aryl group having 6 to 20 carbon atoms, deuterated or non-deuterated condensed ring aryl group having 10 to 20 carbon atoms.

[0014] Further, L1, L2, L3, L4are each independently selected from any one of single bond, deuterated or non-deuterated phenyl group, deuterated or non-deuterated biphenyl group.

[0015] Further, the mass percentage of any one compound in the blue light emitting host composition is between 10 to 75 wt%.

[0016] Further, the mass percentage of any one compound in the blue light emitting host composition is between 10 to 70 wt%.

[0017] Further, the mass percentage of any one compound in the blue light emitting host composition is between 10 to 65 wt%.

[0018] Further, the mass percentage of any one compound in the blue light emitting host composition is between 10 to 60 wt%.

[0019] 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.

[0020] Further, the sum of the mass of the compounds selected from Formula I in the blue light-emitting host composition accounts for not less than 20 wt% of the mass of the blue light-emitting host composition.

[0021] Further, the sum of the mass of the compounds selected from Formula I in the blue light-emitting host composition accounts for not less than 30 wt% of the mass of the blue light-emitting host composition.

[0022] Further, the sum of the mass of the compounds 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.

[0023] Further, the sum of the mass of the compounds 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.

[0024] Further, the sum of the mass of the compounds 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.

[0025] Further, the sum of the mass of the compounds 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.

[0026] Further, the sum of the mass of the compounds 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.

[0027] In combination with the first aspect, the ratio of the sum of the mass of the compounds selected from Formula I to the sum of the mass of the compounds selected from Formula II in the blue light-emitting host composition is 1:9~9:1.

[0028] Further, the ratio of the sum of the mass of the compounds selected from Formula I to the sum of the mass of the compounds selected from Formula II in the blue light-emitting host composition is 2:8~8:2.

[0029] Further, the ratio of the sum of the mass of the compounds selected from Formula I to the sum of the mass of the compounds selected from Formula II in the blue light-emitting host composition is 3:7~7:3.

[0030] Further, the ratio of the sum of the mass of the compounds selected from Formula I to the sum of the mass of the compounds selected from Formula II in the blue light-emitting host composition is 4:6~6:4.

[0031] 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;

[0032] 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.

[0033] In combination with the first aspect, Ar2 is selected from or Any one hydrogen in Ar2 can be replaced by deuterium.

[0034] In combination with the first aspect, Ar2 is selected from 、 、 、 Any one of Ar2 can be replaced by deuterium.

[0035] In combination with the first aspect, Ar1 and Ar3 are each independently selected from any one or a combination of two of deuterated or non-deuterated phenyl, deuterated or non-deuterated biphenyl, deuterated or non-deuterated naphthyl, deuterated or non-deuterated phenanthryl.

[0036] In combination with the first aspect, the difference between the molecular weights of any two compounds among the first host compound, the second host compound and the third host compound is within 100, i.e. the difference between the molecular weights of the first host compound and the second host compound is within 100, the difference between the molecular weights of the first host compound and the third host compound is within 100, and the difference between the molecular weights of the second host compound and the third host compound is within 100.

[0037] 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 the structure is >5%.

[0038] Further, Formula I is selected from the following structures:

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047] ;

[0048] wherein Dn represents n hydrogens are replaced by deuterium, n is a positive integer, and n is 1 to the maximum number of deuterium substitution.

[0049] For example, the following structures can be represented by For example, the following structures can be represented by For example, the following structures can be represented by , , , , and the like.

[0050] In combination with the first aspect, formula II is selected from the following structures:

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064] ;

[0065] wherein Dn represents n hydrogens are replaced by deuterium, n is a positive integer, and has a value from 1 to the maximum number of deuterium substitutions.

[0066] Further, the blue light emitting host composition is selected from any one of the following:

[0067] Composition 1:

[0068]

[0069] Composition 2:

[0070]

[0071] Composition 3:

[0072]

[0073] Composition 4:

[0074]

[0075] Composition 5:

[0076]

[0077] Composition 6:

[0078]

[0079] Composition 7:

[0080]

[0081] Composition 8:

[0082]

[0083] Composition 9:

[0084]

[0085] Composition 10:

[0086]

[0087] Composition 11:

[0088]

[0089] Composition 12:

[0090]

[0091] Composition 13:

[0092]

[0093] Composition 14:

[0094]

[0095] Composition 15:

[0096]

[0097] Composition 16:

[0098]

[0099] Composition 17:

[0100]

[0101] Composition 18:

[0102]

[0103] Composition 19:

[0104]

[0105] Composition 20:

[0106]

[0107] Composition 21:

[0108]

[0109] Composition 22:

[0110]

[0111] Composition 23:

[0112]

[0113] Composition 24:

[0114]

[0115] Composition 25:

[0116]

[0117] Composition 26:

[0118]

[0119] Composition 27:

[0120]

[0121] Composition 28:

[0122]

[0123] Composition 29:

[0124] ;

[0125] 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.

[0126] The 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 which are sequentially arranged on a substrate; wherein the light-emitting layer comprises the blue light-emitting host composition as described above.

[0127] 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.

[0128] The present application has the following beneficial effects:

[0129] 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 in a defined mass ratio range, the melting point of the obtained blue light-emitting host composition is lower than the melting point 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 small compared with the evaporation initial premixed ratio, 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 device driving voltage, but also significantly prolong the device life, and under continuous working conditions, the voltage efficiency and 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 and stable performance. BRIEF DESCRIPTION OF DRAWINGS

[0130] 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.

[0131] Figure 2 It is a DSC curve of compound A-1.

[0132] Figure 3 It is a DSC curve of compound B-1.

[0133] Figure 4 It is a DSC curve of compound C-1.

[0134] Figure 5 It is a DSC curve of the composition mixed by compound A-1, B-1 and C-1 in a mass ratio of 5:3:2.

[0135] Figure 6 It is a DSC curve of the composition mixed by compound A-1 and B-1 in a mass ratio of 5:5. DETAILED DESCRIPTION

[0136] In order to more clearly understand the content of the present application, the embodiments will be described in detail in combination with the drawings.

[0137] 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

[0138] The present application also relates to the use of the compositions as coating materials or printing inks in the production of organic electronic devices, particularly preferably by a printing or coating process.

[0139] 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.

[0140] Experimental Section

[0141] 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 reference to the 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 in an inert atmosphere, under anhydrous conditions. Solvents and reagents can be purchased from conventional reagent suppliers.

[0142] The compounds used in the following compositions can be purchased and synthesized by oneself.

[0143] Composition Example 1

[0144] 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: ​

[0145] ;

[0146] Composition Example 2

[0147] This example 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:

[0148] ;

[0149] Composition Example 3

[0150] This example 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:

[0151] ;

[0152] Composition Example 4

[0153] This example 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:

[0154] ;

[0155] Composition Example 5

[0156] This example 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:

[0157] ;

[0158] Composition Example 6

[0159] This example 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:

[0160] ;

[0161] Composition Example 7

[0162] This example 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:

[0163] ;

[0164] Composition Example 8

[0165] This example 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:

[0166] ;

[0167] Composition Example 9

[0168] This example 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:

[0169] ;

[0170] Composition Example 10

[0171] 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:

[0172] ;

[0173] Composition Example 11

[0174] 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:

[0175] ;

[0176] Composition Example 12

[0177] 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:

[0178] ;

[0179] Composition Example 13

[0180] The embodiment provides a blue light-emitting host composition, which is composed of compound A-13, compound B-13 and compound C-13, and the mass proportion of each compound is shown in Table 1: ;

[0181] Composition embodiment 14

[0182] The embodiment provides a blue light-emitting host composition, which is composed of compound A-14, compound B-14 and compound C-14, and the mass proportion of each compound is shown in Table 1:

[0183] ;

[0184] Composition embodiment 15

[0185] The embodiment provides a blue light-emitting host composition, which is composed of compound A-15, compound B-15 and compound C-15, and the mass proportion of each compound is shown in Table 1:

[0186] ;

[0187] Composition embodiment 16

[0188] The embodiment provides a blue light-emitting host composition, which is composed of compound A-16, compound B-16 and compound C-16, and the mass proportion of each compound is shown in Table 1:

[0189] ;

[0190] Composition embodiment 17

[0191] 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:

[0192] ;

[0193] Composition embodiment 18

[0194] 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:

[0195] ;

[0196] Composition embodiment 19

[0197] 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:

[0198] ;

[0199] Composition embodiment 20

[0200] 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:

[0201] ;

[0202] Composition embodiment 21

[0203] 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:

[0204] ;

[0205] Composition embodiment 22

[0206] 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:

[0207] ;

[0208] Composition embodiment 23

[0209] 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:

[0210] ;

[0211] Composition embodiment 24

[0212] 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:

[0213] ;

[0214] Composition embodiment 25

[0215] The present embodiment 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:

[0216] ;

[0217] Composition Example 26

[0218] The present embodiment 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:

[0219]

[0220] Composition Example 27

[0221] The present embodiment 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:

[0222] ;

[0223] Composition Example 28

[0224] The present embodiment 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:

[0225] ;

[0226] Composition Example 29

[0227] The present embodiment 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:

[0228] ;

[0229] Table 1

[0230]

[0231] Note: The mass ratio in Table 1 refers to the mass ratio of each host compound in the corresponding blue light-emitting host composition.

[0232] Manufacture and characterization of OLEDs

[0233] Device embodiment

[0234] 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.

[0235] 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.

[0236] Further, the light-emitting layer is composed of a host material and a guest material, and the light-emitting layer host material can be composed of one kind of molecular material or multiple kinds of molecular materials.

[0237] The composition provided by the present application can be used in the light-emitting layer of the above-mentioned organic electroluminescent device.

[0238] The anode in the embodiment adopts the anode material commonly used in the art, such as ITO, Ag or a multi-layer structure thereof. The hole injection layer adopts the hole injection material commonly used in the art, and is doped with F4TCNQ, HATCN, NDP-9 and the like. The hole transport layer adopts the hole transport material commonly used in the art. The light-emitting layer adopts the host / guest material composition provided by the present application. The electron transport layer adopts the electron transport material commonly used in the art. The electron injection layer adopts the electron injection material commonly used in the art, such as LiQ, LiF, Yb and the like. The cathode adopts the material commonly used in the art, such as metal Al, Ag or a metal mixture (Ag-doped Mg, Ag-doped Ca and the like).

[0239] The electrode preparation method and the deposition method of each functional layer in the embodiment are all the conventional methods in the art, such as vacuum thermal evaporation or inkjet printing, and will not be described here again. Only some process details in the preparation process and test methods are described as follows:

[0240] Device embodiment 1

[0241] 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℃ 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 after the evaporation was encapsulated, a coating device was used to perform a coating process on the cleaned cover plate with UV glue, the cover plate after the coating process was moved to a pressing section, the substrate after the evaporation 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 the photo-curing of the UV glue was completed, thereby preparing a top-emitting organic electroluminescent device. The structure of the device is shown in Figure 1 .

[0242] 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:

[0243]

[0244]

[0245]

[0246] Device Examples 2-5

[0247] 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 examples 2-5.

[0248] Device Comparative Examples 1-4

[0249] The host compositions in Table 2 were made into organic electroluminescent devices by the above method, and the specific composition combinations are shown in Table 2, to obtain device comparative examples 1-4.

[0250] 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 2 LT97 refers to the time after which the luminous intensity of the prepared blue light device decreases to 97% of its initial value L0 when the device is operated at J = 20 mA / cm

[0251] The test instruments and methods for testing the performance of the above-mentioned example, comparative example OLED devices are as follows:

[0252] The luminous efficiency C.E (cd / A) and color coordinates (CIEy) were tested using a spectral scanner PhotoResearch PR-635;

[0253] Current density and turn-on voltage: tested using a digital source meter Keithley 2400;

[0254] 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);

[0255] Lifetime test: silicon photovoltaic OLED device lifetime test system was used.

[0256] The performance detection results of the above-mentioned devices are shown in Table 2.

[0257] Table 2 Blue light device performance test results

[0258]

[0259] Note: The mass ratio in Table 2 refers to the mass ratio of each host compound in the corresponding host composition.

[0260] As can be seen from the above data, the single host material device of device comparative example 4 has a higher driving voltage, and the efficiency and lifetime are significantly 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 are not obviously improved; the device examples 1-5 provided by the present application not only significantly improve the efficiency of the device and prolong the lifetime of the device, but also appropriately reduce the driving voltage of the device.

[0261] ​Performance test of composition examples

[0262] In order to illustrate the good melting point advantage of the blue light-emitting host composition provided by the present application in the evaporation process, the melting points of the composition examples provided by the present application are measured, and the DSC curves of some components and compositions are shown in FIG. 1. Figures 2 to 5 The measurement results are shown in Table 3.

[0263] Table 3

[0264]

[0265] Note: The melting point tester 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.

[0266] 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 monomer. The composition of comparative example 1 and comparative example 3 has no fixed single melting point. The melting points of the two monomers 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 monomer. The melting point of the blue light-emitting host composition provided by the present application is fixed and is lower than that of each monomer, which is beneficial to the composition provided by the present application to form an organic thin film by evaporation with a constant component ratio.

[0267] 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 by compounds A-1, B-1 and C-1 according to the ratio in Table 2 is 252℃. It can be seen 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 monomer. The lower melting point is beneficial to the composition provided by the present application to form an organic thin film by evaporation with a constant component ratio.

[0268] Figure 6 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 change peak, and has no fixed single melting point. The lack of fixed single melting point may lead to poor component constancy of the composition in the evaporation process.

[0269] Host composition thin film component constancy test

[0270] To further illustrate the advantages of the blue light-emitting host composition provided by the present application, the composition examples are formed into host composition thin films, and the component constancy of the thin films is tested. The host compositions are premixed according to the premixing proportions (referring to the mass proportion of each host compound in the corresponding host composition) of Tables 4-1 to 4-3, and then the premixed host compositions are formed into thin films with a thickness of 2000 Å at different evaporation rates. The above operation is repeated continuously three times (i.e., the same composition is continuously evaporated three times to form thin films at the same premixing proportion), and the mass proportions of each compound in the three thin films formed are determined by high-performance liquid chromatography analysis method. The evaluation results are as follows:

[0271] Table 4-1

[0272]

[0273] Table 4-2

[0274]

[0275] Table 4-3

[0276]

[0277] As can be seen from Tables 4-1 to 4-3, at evaporation 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 films after final evaporation in the effect examples 1-1 to 2-9 composed of the blue light-emitting host composition provided by the present application are relatively constant under continuous working conditions, and the difference with the initial premixing proportion is small.

[0278] At a low evaporation rate of 0.5 Å / s, the mass proportions of each compound in the thin films after final evaporation in the comparative effect examples 1-1 to 1-3 under continuous working conditions have a large difference with the initial premixing proportion, and the evaporation component proportion does not follow the premixing proportion, which does not adversely affect the device performance.

[0279] With the increase of the evaporation rate, although the mass ratio of each compound in the thin film after the final evaporation of the two-component mixed host material of the comparative effect example is closer to the initial premixing ratio, the mass ratio of each compound in the thin film after the final evaporation of the two-component mixed host material has a large fluctuation under continuous operation, and at the evaporation rate of 3 Å / s, it can be seen that the fluctuation of the two-component mixed host material of the comparative effect examples 1-7 to 1-9 is obviously increased, while the blue light emitting host composition of the effect examples 1-7 to 2-9 provided by the application maintains good process stability and component ratio constancy under different evaporation rates, indicating that by using the blue light emitting host composition provided by the application, good component ratio constancy can be maintained under different production processes and continuous operation conditions, and the mass ratio of each compound in the thin film after the final evaporation of the two-component mixed host material of the comparative effect example is greatly different from the initial premixing ratio under different evaporation rates and continuous operation conditions, which is likely to cause the organic film layer components evaporated to be unable to form according to the premixing ratio, resulting in that the premixing advantage cannot be stably played.

[0280] Constant performance test of the device

[0281] 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.

[0282] Table 5

[0283]

[0284] Note: The mass ratio in Table 5 refers to the mass ratio of each host compound in the corresponding host composition.

[0285] As can be seen from the above table, the voltage efficiency and the lifetime of the device examples 1-1 to 1-3 provided by the application are relatively stable, and are all better than those of the device comparative examples. As can 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 that the composition constancy of the composition is poor during the evaporation process, the mass ratio of each compound in the thin film after the final evaporation is greatly different from the initial premixing ratio, which causes the device performance of the device comparative examples to fluctuate greatly, while the melting point of the blue light emitting host composition provided by the application is lower than that of each single body, and the lower melting point is conducive to the evaporation of the composition provided by the application to form an organic thin film with constant component ratio, so the device performance of the device examples prepared under continuous operation conditions is more stable, which indicates that the application is more suitable for commercial mass production.

[0286] Obviously, the above-mentioned embodiments of the present application are only examples for clearly explaining the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art, and it is impossible to enumerate all the embodiments here. Any obvious changes or variations derived from the technical solutions of the present application are still within the protection scope of the present application.

Claims

1. A blue luminescent host composition, characterized in that, It comprises at least a first main compound, a second main compound, and a third main compound; the structure of the first main compound is shown in Formula I, the structure of the second main compound is shown in Formula II, and the structure of the third main compound is shown in Formula I or Formula II. The first main compound, the second main compound, and the third main compound are different from each other; AND, II; Ar1 and Ar3 are each independently selected from any one or any combination of two of the following: aryl groups with 6 to 30 deuterated or non-deuterated carbon atoms, and fused-ring aryl groups with 10 to 30 deuterated or non-deuterated carbon atoms. Ar2 is selected from substituted or unsubstituted dibenzofuranyl groups; when Ar2 has substituents, the substituents are selected from any one or a combination of two of deuterium and aryl groups having 6 to 30 carbon atoms. Ar4 is selected from , , , Any one of the hydrogen atoms in Ar4 can be replaced by deuterium; L1, L2, L3, and L4 are each independently selected from any one of aryl groups with 6 to 30 carbon atoms, whether single-bonded, deuterated, or non-deuterated. The mass percentage of any one compound in the blue luminescent host composition is between 10 and 80 wt%. The difference in molecular weight between any two compounds in the first, second, and third main compounds is within 100; 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 luminescent 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 luminescent host composition is 0.2~8:0.1~7:

1.

2. The blue light-emitting host composition according to claim 1, characterized in that, Ar2 is selected from or Any hydrogen atom in Ar2 can be replaced by deuterium.

3. The blue luminescent host composition according to claim 1, characterized in that, Ar1 and Ar3 are each independently selected from any one or any combination of two of the following: deuterated or non-deuterated phenyl, deuterated or non-deuterated biphenyl, deuterated or non-deuterated naphthyl, and deuterated or non-deuterated phenanthryl.

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

5. The blue luminescent host composition according to claim 1, characterized in that, Formula I is selected from the structure shown below: ； Where Dn represents n hydrogen atoms being replaced by deuterium, and n is a positive integer, ranging from 1 to the maximum deuterium algebra.

6. The blue luminescent host composition according to claim 1, characterized in that, Formula II is selected from the structure shown below: ； Where Dn represents n hydrogen atoms being replaced by deuterium, and n is a positive integer, ranging from 1 to the maximum deuterium algebra.

7. The blue luminescent host composition according to claim 1, characterized in that, The blue luminescent 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, compounds A-1 to A-29 are the first main compounds, compounds B-1 to B-29 are the second main compounds, and compounds C-1 to C-29 are the third main compounds.

8. An organic electroluminescent device, characterized in that, It includes an anode, a hole transport region, a light-emitting layer, an electron transport region, and a cathode sequentially disposed on a substrate; wherein the light-emitting layer includes the blue light-emitting host composition as described in any one of claims 1 to 7.

9. The organic electroluminescent device according to claim 8, characterized in that, 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 in any one of claims 1 to 7.

Images