A blue light-emitting compound containing a dibenzofuran structure, a composition containing the same, and an organic electroluminescent device

Abstract

The present invention discloses a blue light-emitting compound containing a dibenzofuran structure, a composition containing the same, and an organic electroluminescent device. The general structural formula of the blue light-emitting compound is shown in Formula I-1 or Formula I-2, and L1 and L2 each independently represent a phenylene group or a biphenylene group. The blue light-emitting compound provided by the present invention can significantly weaken the influence of the dibenzofuran fragment on the multiple resonance and improve the luminescence half-width of the material by adding a spacer between the diaryl furan structure and the MR-TADF multiple resonance plane. In addition, after using the dibenzofuran fragment in both the guest material and the luminescent host material, the intermolecular distance is increased due to the mutual repulsion of the lone pair of electrons of the oxygen atom, and the adverse effect of Dexter energy transfer on the luminous efficiency of the device is reduced. #imgabs0#I-1;#imgabs1#I-2.

Description

Technical Field

[0001] The invention belongs to the technical field of OLED, and specifically comprises a blue light-emitting compound containing a dibenzofuran structure, a composition containing the blue light-emitting compound, and an organic electroluminescent device. Background Art

[0002] As market demand continues to increase, the efficiency requirements for blue light devices are getting higher and higher. In current OLED devices, multiple resonance effect induced thermally activated delayed fluorescence (MR-TADF) materials have become a hot topic in the field of organic electroluminescence (OEL) in recent years due to their advantages such as high efficiency and narrow-band luminescence. In previous studies, it was found that the introduction of fluorene / diarylfuran structures into MR-TADF materials can keep the energy level of the material between 4.4-4.6eV, and also maintain a large excited state singlet value (S1), which can meet the device's demand for deep blue light from the material.

[0003] As the research continues, it is found that the above structure is too close to the resonance center of MR-TADF, which will affect the orbital transition of the material during the luminescence process. Its lowest unoccupied orbital (LUMO) is not distributed on the plane of multiple resonances, but appears on the substituents of the fluorene / diarylfuran structure. This type of orbital transition will increase the half-peak width of the material spectrum, reduce the color purity, and affect the efficiency of the device.

[0004] In OLED devices, the Dexter energy transfer of triplet excitons from the host material to the MR-TADF guest material is the main way to cause energy loss in the fluorescence process and should be avoided. In previous studies, this process was mainly suppressed by introducing units such as tert-butylbenzene with large steric hindrance into the MR-TADF guest, but the introduction of such units would affect the transport and recombination of carriers, resulting in an increase in the driving voltage of the device. Summary of the invention

[0005] In view of the above problems existing in the prior art, the present invention provides a blue light-emitting compound containing a dibenzofuran structure, a composition containing the same, and an organic electroluminescent device.

[0006] To achieve the above objectives, the technical solutions adopted by the present invention include:

[0007] The first aspect of the present invention provides a blue light-emitting compound containing a dibenzofuran structure, characterized in that the general structural formula of the blue light-emitting compound is as shown in Formula I-1 or Formula I-2:

[0008] I-1; I-2;

[0009] Wherein, the R0 represents a tert-butyl group;

[0010] R1 represents a single substituent to the maximum permissible substituent, selected from any one of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 30 carbon atoms, substituted or unsubstituted alkenyl having 2 to 30 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 30 carbon atoms, substituted or unsubstituted aryl having 6 to 60 carbon atoms, substituted or unsubstituted heteroaryl having 5 to 60 carbon atoms, substituted or unsubstituted condensed ring aryl having 5 to 60 carbon atoms, substituted or unsubstituted heterocondensed ring aryl having 5 to 60 carbon atoms, and substituted or unsubstituted amine; two or more R1s may be connected to form a ring structure;

[0011] R2 represents any one of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 30 carbon atoms, substituted or unsubstituted alkoxy having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 30 carbon atoms, substituted or unsubstituted aryl having 6 to 60 carbon atoms, substituted or unsubstituted heteroaryl having 5 to 60 carbon atoms, substituted or unsubstituted condensed ring aryl having 5 to 60 carbon atoms, substituted or unsubstituted heterocondensed ring aryl having 5 to 60 carbon atoms, and substituted or unsubstituted amine;

[0012] L1 and L2 each independently represent a phenylene group or a biphenylene group;

[0013] Ar1 and Ar2 are the same or different and each independently represents one of the following structures:

[0014] II. III;

[0015] R3, R4, and R5 each represent a single substituent to the maximum permissible substituent, and the R3, R4, and R5 are the same or different, and each independently represents any one of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 30 carbon atoms, substituted or unsubstituted alkenyl having 2 to 30 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 30 carbon atoms, substituted or unsubstituted aryl having 6 to 60 carbon atoms, substituted or unsubstituted heteroaryl having 5 to 60 carbon atoms, substituted or unsubstituted condensed ring aromatic having 5 to 60 carbon atoms, substituted or unsubstituted heterocondensed ring aromatic having 5 to 60 carbon atoms, and substituted or unsubstituted amine; two or more R5s may each be connected to form a ring structure;

[0016] m, n, p, q each independently represent 0, 1, 2, 3 or 4;

[0017] In formula I-1 and formula I-2, any hydrogen may be replaced by deuterium, and any nitrogen may be replaced by 15N substitution, any sulfur can be 33 S. 34 S or 36 S is substituted, any oxygen can be 17 O or 18 O substitution, any carbon can be 13 C substitution, any boron can be 11 B replaces;

[0018] * indicates the site of attachment to Formula I.

[0019] Furthermore, Ar1 represents one of the following structures:

[0020] , , , , .

[0021] Further, Ar2 represents one of the structures shown below:

[0022] , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , .

[0023] Furthermore, the R1 is selected from any one of hydrogen and tert-butyl, and two adjacent R1 can be connected to form a tetramethylcyclohexyl group.

[0024] Furthermore, R2 is selected from any one of hydrogen, methyl, deuterium-substituted or unsubstituted tert-butyl, and cyclohexyl.

[0025] Furthermore, the blue light-emitting compound is selected from one of the following structures:

[0026] .

[0027] The second aspect of the present invention provides a blue light-emitting composition, which comprises the blue light-emitting compound as described above, and a compound having a general structural formula as shown in Formula IV:

[0028] IV;

[0029] in,

[0030] Ar3 represents a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group;

[0031] Ar4 represents a structure shown in Formula V-1 to Formula V-5:

[0032] Ⅴ-1、 Ⅴ-2,

[0033] Ⅴ-3. Ⅴ-4,

[0034] Ⅴ-5;

[0035] R 10 -R 61 each independently represents hydrogen or deuterium;

[0036] In formula V-1,

[0037] When R 10 -R 13 When any one of them is deuterium, the others are also deuterium;

[0038] When R 14 , R 15 When one of them is deuterium, the other is also deuterium;

[0039] When R 16 -R 19 When any one of them is deuterium, the others are also deuterium;

[0040] In formula V-2,

[0041] When R 20 -R 23 When any one of them is deuterium, the others are also deuterium;

[0042] When R 24 , R 25 When one of them is deuterium, the other is also deuterium;

[0043] When R 26 -R 29 When any one of them is deuterium, the others are also deuterium;

[0044] In formula V-3,

[0045] When R 30 -R 33 When any one of them is deuterium, the others are also deuterium;

[0046] When R 34 , R 35When one of them is deuterium, the other is also deuterium;

[0047] When R 36 -R 39 When any one of them is deuterium, the others are also deuterium;

[0048] In formula V-4,

[0049] When R 40 -R 43 When any one of them is deuterium, the others are also deuterium;

[0050] When R 44 -R 47 When any one of them is deuterium, the others are also deuterium;

[0051] In formula V-5,

[0052] When R 50 -R 54 When any one of them is deuterium, the others are also deuterium;

[0053] When R 55 -R 57 When any one of them is deuterium, the others are also deuterium;

[0054] When R 58 -R 61 When any one of them is deuterium, the others are also deuterium;

[0055] D represents a single substituent to the maximum permissible substituent, selected from deuterium;

[0056] t represents an integer from 0 to 8;

[0057] L3 and L4 are the same or different and each independently represents a single bond or a phenylene group;

[0058] In formula IV, any hydrogen can be replaced by deuterium, and any nitrogen can be replaced by 15 N substitution, any sulfur can be 33 S. 34 S or 36 S is substituted, any oxygen can be 17 O or 18 O substitution, any carbon can be 13 C substitution, any boron can be 11 B replaced.

[0059] Further, Ar4 represents one of the structures shown below:

[0060] , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , .

[0061] Furthermore, Ar3 represents a deuterated phenyl group or a deuterated naphthyl group.

[0062] Furthermore, the compound represented by formula IV is selected from one of the structures shown below:

[0063] .

[0064] The third 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 arranged in sequence on a substrate; the light-emitting layer includes one or more blue light-emitting compounds as described above.

[0065] Furthermore, the light-emitting layer includes a host material and a guest material, and the guest material includes one or more blue light-emitting compounds as described above.

[0066] The fourth 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 arranged in sequence on a substrate; wherein the light-emitting layer includes one or more blue light-emitting compositions as described above.

[0067] Furthermore, the light-emitting layer includes a host material and a guest material, the guest material includes one or more blue light-emitting compounds with a general structural formula as shown in Formula I-1 or Formula I-2, and the host material includes one or more compounds with a general structural formula as shown in Formula IV.

[0068] Beneficial effects of the present invention:

[0069] Firstly, the blue light-emitting compound provided by the present invention can effectively block the influence of the diarylfuran structure on the excitation / emission process of the material and improve the luminescence half-width of the material by adding a spacer between the diarylfuran structure and the MR-TADF multiple resonance plane.

[0070] Secondly, after using dibenzofuran fragments in both the guest material and the luminescent host material, due to the repulsive effect of the lone pair of electrons of the oxygen atom, the combined use of the BD material and the BH material with a specific structure can improve the dispersion of the BD material in the host material, increase the distance between molecules, reduce the adverse effect of Dexter energy transfer on the luminous efficiency of the device, and reduce the exciton quenching caused by excessive local exciton concentration, thereby improving the device efficiency. Therefore, the composition provided by the present invention is applied to the preparation of organic electroluminescent devices, which can significantly improve the device efficiency and material life. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 It is a schematic structural diagram of the organic electroluminescent device of the present invention.

[0072] Figure 2 This is the PL spectrum of B1 in Synthesis Example 1 of the present invention.

[0073] In the figure: 1-substrate, 2-anode, 3-hole injection layer, 4-hole transport layer, 5-electron blocking layer, 6-light-emitting layer, 7-hole blocking layer, 8-electron transport layer, 9-electron injection layer, 10-cathode, 11-covering layer. DETAILED DESCRIPTION

[0074] In order to more clearly understand the content of the present invention, it will be described in detail with reference to the drawings and embodiments.

[0075] The organic compound of the present invention is suitable for use in light-emitting elements, display panels and electronic devices, and is particularly suitable for use in organic electroluminescent devices. The electronic device of the present invention is a device comprising a layer of at least one organic compound, and the device 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). The schematic structural diagram of an exemplary organic electroluminescent device is shown in FIG. Figure 1 shown.

[0076] Experimental Section

[0077] In order to understand the content of the present invention more clearly, the luminescent characteristics of the organic compound, the preparation method of the organic compound and 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 indicated, the subsequent synthesis is carried out in anhydrous solvent under a protective gas atmosphere. Solvents and reagents can be purchased from conventional reagent suppliers.

[0078] Synthesis of compounds

[0079] Intermediate synthesis

[0080]

[0081] The intermediate synthesis route is as above. The target intermediate A can be obtained by two steps of common Buchwald-Hartwig coupling synthesis method. X can be Br or I according to different specific structures.

[0082] The specific cases are as follows:

[0083]

[0084] Sub-1 (71.8 g, 100 mmol), Sub-2 (25.9 g, 100 mmol) and sodium tert-butoxide (11.1 g, 150 mol) were added to toluene (1000 mL), and then bis(dibenzylideneacetonepalladium) (1.69 g, 3 mmol) and BINAP (3.73 g, 6 mmol) were introduced under nitrogen protection. The reaction system was then heated to 110°C, refluxed and maintained for 8 hours, cooled to room temperature, quenched with water and separated, the organic phase was filtered and dried over anhydrous sodium sulfate, the solvent was removed by rotation, and the crude product was purified by column chromatography to obtain the product Sub-3: 70.6 g, yield: 75%, MS (m / z) (M+): 941.5.

[0085] Sub-3 (70.6 g, 75 mmol), Sub-4 (108.8 g, 75 mmol) and sodium tert-butoxide (8.3 g, 112 mol) were added to toluene (1000 mL), and then bis(dibenzylideneacetonepalladium) (1.13 g, 2 mmol) and tri-tert-butylphosphine (0.8 g, 4 mmol) were introduced under nitrogen protection. The reaction system was then heated to 110°C, refluxed and maintained for 8 hours, cooled to room temperature, quenched with water and separated, the organic phase was filtered and dried over anhydrous sodium sulfate, the solvent was removed by rotation, and the crude product was purified by column chromatography to obtain product A1: 59.7 g, yield: 66%, MS (m / z) (M+): 1205.6.

[0086] Synthesis Example 1

[0087]

[0088] Under nitrogen protection, the system was maintained at -30°C to -40°C, and n-butyllithium solution (15.4 mL, 20 mmol) was slowly added dropwise to a tert-butylbenzene (100 mL) solution containing A1 (12.1 g, 10 mmol), followed by heating and stirring at 60°C for 6 hours. Boron tribromide (5.0 g, 20 mmol) was then added dropwise at -30°C, and the reaction system was stirred at 60°C for 6 hours. Finally, N,N-diisopropylethylamine (2.6 g, 20 mmol) was added at 0°C, and the reaction system was stirred at room temperature for 2 hours. 150 mL of deionized water was added to the reaction system to quench the residual boron tribromide. The mixture was extracted with 200 mL of dichloromethane, the organic layers were combined, concentrated in vacuo, and purified by column chromatography with a mixed eluent of dichloromethane / petroleum ether (1:20, v / v). The crude product was recrystallized from n-heptane, acetone and toluene to finally obtain product B1: 0.50 g, yield: 4.4%, MS (m / z) (M+): 1135.7. Figure 2 This is the PL spectrum of Synthesis Example B1, and the half-peak width is 20.9 nm.

[0089] Synthesis Example 2

[0090]

[0091] The preparation method is the same as that of Example 1, except that A2 (12.63 g; 10 mmol) replaces A1, and finally the product B2 is obtained: 0.91 g, yield: 7.65%, MS (m / z) (M+): 1191.6.

[0092] Synthesis Example 3

[0093]

[0094] The preparation method is the same as that of Example 1, except that A3 (12.61 g; 10 mmol) replaces A1, and finally the product B3 is obtained: 0.68 g, yield: 5.69%, MS (m / z) (M+): 1189.6.

[0095] Synthesis Example 4

[0096]

[0097] The preparation method is the same as that of Example 1, except that A4 (13.67 g; 10 mmol) replaces A1, and finally the product B4 is obtained: 0.75 g, yield: 5.78%, MS (m / z) (M+): 1295.7.

[0098] Synthesis Example 5

[0099]

[0100] The preparation method is the same as that of Example 1, except that A5 (12.57 g; 10 mmol) is used to replace A1, and the final product B5 is 0.60 g, with a yield of 5.08%, and MS (m / z) (M+): 1185.5.

[0101] Synthesis Example 6

[0102]

[0103] The preparation method is the same as that of Example 1, except that A6 (12.57 g; 10 mmol) is used to replace A1, and the final product B6 is 0.83 g, with a yield of 7.01%, and MS (m / z) (M+): 1185.5.

[0104] Synthesis Example 7

[0105]

[0106] The preparation method is the same as that of Example 1, except that A7 (12.12 g; 10 mmol) is used to replace A1, and the final product B7 is 0.48 g, with a yield of 0.0422, and MS (m / z) (M+): 1140.5.

[0107] Synthesis Example 8

[0108]

[0109] The preparation method is the same as that of Example 1, except that A8 (12.22 g; 10 mmol) is used to replace A1, and the final product B8 is 0.83 g, with a yield of 0.0684, MS (m / z) (M+): 1219.6.

[0110] Synthesis Example 9

[0111]

[0112] The preparation method is the same as that of Example 1, except that A9 (13.41 g; 10 mmol) replaces A1, and the final product B9 is 0.98 g, with a yield of 7.72%, and MS (m / z) (M+): 1269.7.

[0113] Synthesis Example 10

[0114]

[0115] The preparation method was the same as that of Example 1, except that A10 (13.17 g; 10 mmol) was used to replace A1, and the final product B10 was obtained: 0.68 g, yield: 0.0542, MS (m / z) (M+): 1245.7.

[0116] Synthesis Example 11

[0117]

[0118] The preparation method is the same as that of Example 1, except that A11 (11.53 g; 10 mmol) is used to replace A1, and finally the product B11 is obtained: 0.53 g, yield: 0.0486, MS (m / z) (M+): 1081.4.

[0119] Synthesis Example 12

[0120]

[0121] The preparation method is the same as that of Example 1, except that A12 (12.03 g; 10 mmol) is used to replace A1, and the final product B12 is 0.35 g, with a yield of 0.0305, and MS (m / z) (M+): 1131.4.

[0122] Synthesis Example 13

[0123]

[0124] The preparation method is the same as that of Example 1, except that A13 (12.91 g; 10 mmol) is used to replace A1, and the final product B13 is 0.51 g, with a yield of 0.0419, and MS (m / z) (M+): 1219.6.

[0125] Synthesis Example 14

[0126]

[0127] The preparation method was the same as that of Example 1, except that A14 (12.9 g; 10 mmol) was used to replace A1, and the final product B14 was obtained: 0.38 g, yield: 0.0311, MS (m / z) (M+): 1218.6.

[0128] Synthesis Example 15

[0129]

[0130] C1 (5.2 g, 20 mmol), E1 (6.0 g, 20 mmol) and potassium carbonate (4.1 g, 30 mmol) were added to a 300 ml toluene / water mixture (toluene / water = 4:1, v / v), and then tetrakistriphenylphosphine palladium (1.2 g, 1 mmol) was introduced under nitrogen protection. The reaction system was then heated to 110°C, refluxed and maintained for 8 hours, cooled to room temperature, quenched with water and separated, the organic phase was dried over anhydrous sodium sulfate, the solvent was removed by rotation, and the crude product was separated and purified by a mixed column of petroleum ether / dichloromethane, wherein the volume ratio of petroleum ether / dichloromethane was 10:1. Finally, the product F1 was obtained: 5.1 g, yield: 54%, MS (m / z) (M+): 477.

[0131] Synthesis Example 16

[0132]

[0133] Using the same method as in Synthesis Example 15, C2 (5.6 g, 20 mmol) and E2 (6.1 g, 20 mmol) were used to replace C1 and E1, and finally the product F2 was obtained: 7.4 g, yield: 73%, MS (m / z) (M+): 505.

[0134] Synthesis Example 17

[0135]

[0136] Using the same method as in Synthesis Example 15, C3 (4.1 g, 20 mmol) and E3 (7.1 g, 20 mmol) were used to replace C1 and E1, and finally the product F3 was obtained: 6.2 g, yield: 65%, MS (m / z) (M+): 483.

[0137] Synthesis Example 18

[0138]

[0139] Using the same method as in Synthesis Example 15, C4 (5.2 g, 20 mmol) and E4 (6.1 g, 20 mmol) were used to replace C1 and E1, and finally the product F4 was obtained: 7.2 g, yield: 74%, MS (m / z) (M+): 480.

[0140] Synthesis Example 19

[0141]

[0142] Using the same method as in Synthesis Example 15, C5 (5.1 g, 20 mmol) and E5 (7.3 g, 20 mmol) were used to replace C1 and E1, and finally the product F5 was obtained: 5.6 g, yield: 52%, MS (m / z) (M+): 540.

[0143] Synthesis Example 20

[0144]

[0145] Using the same method as in Synthesis Example 15, C6 (5.1 g, 20 mmol) and E6 (7.1 g, 20 mmol) were used to replace C1 and E1, and finally the product F6 was obtained: 8.3 g, yield: 78%, MS (m / z) (M+): 532.

[0146] Synthesis Example 21

[0147]

[0148] Using the same method as in Synthesis Example 15, C7 (5.1 g, 20 mmol) and E7 (6.2 g, 20 mmol) were used to replace C1 and E1, and finally the product F7 was obtained: 7.6 g, yield: 78%, MS (m / z) (M+): 487.

[0149] Synthesis Example 22

[0150]

[0151] Using the same method as in Synthesis Example 15, C8 (5.1 g, 20 mmol) and E8 (7.3 g, 20 mmol) were used to replace C1 and E1, and finally the product F8 was obtained: 8.6 g, yield: 80%, MS (m / z) (M+): 540.

[0152] Synthesis Example 23

[0153]

[0154] Using the same method as in Synthesis Example 15, C9 (5.1 g, 20 mmol) and E9 (6 g, 20 mmol) were used to replace C1 and E1, and finally the product F9 was obtained: 6.3 g, yield: 66%, MS (m / z) (M+): 475.

[0155] Synthesis Example 24

[0156]

[0157] Using the same method as in Synthesis Example 15, C10 (5.4 g, 20 mmol) and E10 (6.2 g, 20 mmol) were used to replace C1 and E1, and finally the product F10 was obtained: 5.3 g, yield: 54%, MS (m / z) (M+): 488.

[0158] Comparative compounds

[0159] D1. D2, D3,

[0160] D4, D5. D6.

[0161] Material properties

[0162] This case puts forward a viewpoint: by adding a spacer, the effect of dibenzofuran fragments on multiple resonance can be significantly reduced, and the half-peak width of the luminescence of the material can be improved; in addition, after using dibenzofuran fragments in both the guest material and the luminescent host, the mutual repulsion of the lone pair of electrons of the oxygen atom can increase the distance between molecules and reduce the adverse effect of Dexter energy transfer on efficiency. In order to better verify the above viewpoint, the following test was conducted.

[0163] 1) Half peak width of the material

[0164] The half-width of the material is tested using the following method:

[0165] The sample to be tested was prepared into 1*10 -7 The photoluminescence spectrum of the sample was tested using a HORIBA Scientific fluorescence spectrometer, and the half-peak width of the luminescence spectrum was recorded.

[0166] In order to illustrate that the compounds provided by the present invention have unique advantages, the molecular structure characteristics of the guest material are calculated, and the molecular structure is geometrically optimized (Optimization) based on the density functional theory (DFT) calculation method using Orca software, and TDDFT is used for further calculation under this structure to obtain the HOMO and S1 of the compound.

[0167] The test results are shown in Table 1.

[0168] Table 1

[0169]

[0170] It can be seen that the BD material used in this case has a significantly reduced half-peak width compared to D1-D4 by adding a spacer.

[0171] 2) The distance between molecules of the material

[0172] The intermolecular distances of the materials were evaluated using the following method:

[0173] Using Gromacs 2019.3 software, based on the GAFF force field and RESP atomic charge, a 10*10*10nm cubic box was constructed. Using the same host-guest doping ratio as the device of the present invention, the conjugate gradient method was used to randomly place the host-guest molecules into the box and minimize the energy to eliminate the repulsion caused by the unreasonable arrangement of molecules in the system. After that, a 100ps equilibrium MD simulation was performed under NVT to fully balance the system. Based on this system, a 5ns generative MD simulation was performed under the external environment settings of 1atm and 298K based on NPT with periodic boundary conditions. The last 2ns MD trajectory was divided into 20 parts to calculate the average distance between the host and guest molecules in the present invention.

[0174] The host and guest molecular structures used in MD simulations were obtained by Orca software based on the density functional theory (DFT) calculation method (the basis set level was set to: b3lyp / 6-31G(d), and the charge number was 0) by performing geometric optimization and vibration analysis (Opt+freq) on the molecular structures.

[0175] The test results are shown in Table 2.

[0176] Table 2

[0177]

[0178]

[0179] It can be seen from Table 2 that the combination of BD material and BH material disclosed in this case can significantly increase the energy transmission distance between molecules and improve the dispersion of BD material.

[0180] Fabrication and characterization of OLEDs

[0181] Device Example 1

[0182] The substrates used in the present invention were subjected to the following operations: the ITO substrate was patterned so that its luminous area had a size of 3 mm×3 mm, and then water / isopropanol ultrasound, 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 so that the vacuum rate became 1×10 -7 torr.

[0183] Subsequently, the following operations were performed: first, HTL-1 and p-dopant-1 (the mass ratio of HTL-1 to p-dopant-1 was 97:3) were vacuum deposited on the ITO layer (anode) formed on the substrate with a thickness of 10 nm to form a hole injection layer; secondly, HTL-1 was vacuum deposited on the hole injection layer with a thickness of 120 nm to form a hole transport layer; secondly, EB-1 was vacuum deposited on the hole transport layer with a thickness of 5 nm to form an electron blocking layer; secondly, a mixture of F3 and B1 was vacuum deposited on the electron blocking layer with a thickness of 20 nm to form a light-emitting layer, wherein F3 was used as a host and B1 was used as a guest, and the mass ratio of the host to the guest was 98:2; then, HB-1 was vacuum deposited on the light-emitting layer with a thickness of 5 nm to form a hole blocking layer; and then, ETL-1 and LiQ (the mass ratio of ET-1 to LiQ is 1:1) are vacuum deposited with a thickness of 20nm to form an electron transport layer; then Yb is vacuum deposited with a thickness of 1nm on the electron transport layer to form an electron injection layer, and then Mg and Ag (the mass ratio of Mg to Ag is 1:9) are deposited with a thickness of 15nm on the electron injection layer to form a cathode, and then CPL-1 is deposited with a thickness of 50nm on the cathode to form a covering layer. Finally, the vapor-deposited substrate is packaged, and the cleaned cover plate is coated with UV glue using a glue coating device, and then the coated cover plate is moved to a pressing section, and the vapor-deposited substrate is placed on the upper end of the cover plate. Finally, the substrate and the cover plate are bonded by a bonding device, and the UV glue is light-cured to prepare a laminated organic electroluminescent device.

[0184] In addition to the materials used in the present invention, the molecular structures of the remaining materials in each layer of the device are as follows:

[0185]

[0186]

[0187] Device Examples 2-14

[0188] The above method is used to prepare the compounds described in the examples into organic electroluminescent devices, wherein B2-B14 are used to replace B1 to prepare organic electroluminescent device examples 2-14.

[0189] Device Comparison Examples 1-4

[0190] The above method was used to prepare the compound described in the example into an organic electroluminescent device, wherein D1-D4 were used to replace B1 to prepare organic electroluminescent device comparative examples 1-4.

[0191] Device Examples 15-43

[0192] Device Examples 15-43 use the BD and BH materials in Table 3-2 to replace B1 and F3 in the above Device Example 1, respectively.

[0193] Device Comparison Examples 5-12

[0194] Device Examples 5-12 use the BD and BH materials in Table 3-2 to replace B1 and F3 in the above Device Example 1, respectively.

[0195] 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 LT95, the luminous brightness drops to 95% of its initial value L0 after time LT95.

[0196] The test instruments and methods for testing the performance of the OLED devices in the above embodiments and comparative examples are as follows:

[0197] The luminous efficiency CE (cd / A) and color coordinates (CIEy) were tested using a spectrum scanner PhotoResearch PR-635;

[0198] Current density and lighting voltage: tested using a digital source meter Keithley 2400;

[0199] The luminous efficiency of blue light devices is greatly affected by chromaticity. The industry generally uses 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);

[0200] Life test: Use silicon photoelectric OLED device life test system.

[0201] The test results are shown in Table 3-1 and Table 3-2.

[0202] Table 3-1

[0203]

[0204] Table 3-2

[0205]

[0206] It can be seen from the above device examples 1-14 and device comparative examples 1-4 that the BD structure described in this case improves the half-peak width of the spectrum and reduces the loss of light during device transmission, thereby improving the device efficiency. At the same time, due to the deuteration of furan, the device life can also be further improved.

[0207] By using the combination of BD and BH described in this case, and utilizing the repulsive effect of the lone pair of electrons of the oxygen atom in dibenzofuran, the device efficiency is significantly improved and the material life is also improved after increasing the Dexter energy transmission distance and improving the dispersion of the BD material. At the same time, since the BD structure weakens the adverse effects of the dibenzofuran fragment, for device comparative examples 7 and 8, although the Dexter energy transmission distance is also increased, since the furan structure and the luminescent center are directly connected without using a spacer, the device efficiency of this combination is significantly lower than that of the combination described in this case. For device comparative example 10, compared with phenyl or biphenyl, it has a longer spacer, which will cause the spectrum to become wider due to a stronger conjugation effect, thereby reducing the luminous efficiency of the device.

[0208] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A blue luminescent compound containing a dibenzofuran structure, characterized in that: The general structural formula of the blue light-emitting compound is shown in Formula I-1 or Formula I-2: I-1; I-2; Wherein, the R0 represents a tert-butyl group; R1 represents a single substituent selected from an alkyl group having 1 to 30 carbon atoms; R2 represents any one of hydrogen, an alkyl group having 1 to 30 carbon atoms, and a cycloalkyl group having 3 to 30 carbon atoms; L1 and L2 each independently represent a phenylene group; Ar1 represents one of the following structures: 、 、 、 、 ； Ar2 represents one of the following structures: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 ； m means 1.

2. A blue luminescent compound containing a dibenzofuran structure, characterized in that: The blue light-emitting compound is selected from one of the following structures: 。 3. A blue light-emitting composition, characterized in that: The blue light-emitting composition comprises the blue light-emitting compound according to any one of claims 1 to 2, and a compound having a general structural formula as shown in Formula IV: Ⅳ； in, Ar3 represents one of phenyl, naphthyl, deuterated phenyl, and deuterated naphthyl; Ar4 represents a structure shown in Formula V-1 to Formula V-5: Ⅴ-1、 Ⅴ-2、 Ⅴ-3、 Ⅴ-4、 Ⅴ-5； R 10 -R 61 each independently represents hydrogen or deuterium; In formula V-1, When R 10 -R 13 When any one of them is deuterium, the others are also deuterium; When R 14 , R 15 When one of them is deuterium, the other is also deuterium; When R 16 -R 19 When any one of them is deuterium, the others are also deuterium; In formula V-2, When R 20 -R 23 When any one of them is deuterium, the others are also deuterium; When R 24 , R 25 When one of them is deuterium, the other is also deuterium; When R 26 -R 29 When any one of them is deuterium, the others are also deuterium; In formula V-3, When R 30 -R 33 When any one of them is deuterium, the others are also deuterium; When R 34 , R 35 When one of them is deuterium, the other is also deuterium; When R 36 -R 39 When any one of them is deuterium, the others are also deuterium; In formula V-4, When R 40 -R 43 When any one of them is deuterium, the others are also deuterium; When R 44 -R 47 When any one of them is deuterium, the others are also deuterium; In formula V-5, When R 50 -R 54 When any one of them is deuterium, the others are also deuterium; When R 55 -R 57 When any one of them is deuterium, the others are also deuterium; When R 58 -R 61 When any one of them is deuterium, the others are also deuterium; D represents a single substituent to the maximum permissible substituent, selected from deuterium; t represents an integer from 0 to 8; L3 and L4 are the same or different and each independently represents a single bond or a phenylene group; In formula IV, any hydrogen may be replaced by deuterium.

4. The blue light-emitting composition according to claim 3, characterized in that: The Ar4 represents one of the structures shown below: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 。 5. The blue light-emitting composition according to claim 3, characterized in that: The compound represented by formula IV is selected from one of the structures shown below: 。 6. 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 which are sequentially arranged on a substrate; wherein the light-emitting layer includes a host material and a guest material, and the guest material includes one or more blue light-emitting compounds as described in any one of claims 1-2.

7. An organic electroluminescent device, characterized in that: It 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 one or more blue light-emitting compositions as described in any one of claims 3 to 5.

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