WO2022206830A1 - Benzofluorene compound and organic electroluminescent device - Google Patents

Abstract

The present application relates to the field of electroluminescence. Disclosed are a benzofluorene compound and an organic electroluminescent device. The structural formula of the benzofluorene compound is as shown in formula (I), and the organic electroluminescent device using the material of the compound of the present application has lower driving voltage, higher current efficiency, and longer service life.

Description

Benzofluorenes and Organic Electroluminescent Devices

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese patent application with the application number 202110348950.3 and the application title "Benzofluorene Compounds and Organic Electroluminescent Devices" filed with the China Patent Office on March 31, 2021, the entire contents of which are incorporated by reference in this application.

technical field

The present application relates to the field of electroluminescence, in particular to a benzofluorene compound and an organic electroluminescence device.

Background technique

At present, organic electroluminescence (OLED) display technology has been applied in smart phones, tablet computers and other fields, and will further expand to large-scale application fields such as TVs. In the development process of nearly 30 years, people have developed various OLED materials with excellent performance, and through different designs of device structures and optimization of device life, efficiency and other properties, the commercialization process of OLED has been accelerated, making OLEDs are widely used in display and lighting fields.

In order to meet people's higher requirements for OLED devices, there is an urgent need to develop more types and higher performance OLED materials in the art.

SUMMARY OF THE INVENTION

The present application discloses a benzofluorene compound and an organic electroluminescence device. The organic electroluminescence device using the material of the compound of the present application has lower driving voltage, higher current efficiency and longer life.

In order to achieve the above purpose, the application provides the following technical solutions:

A benzofluorene compound, as shown in formula (I),

Wherein, Ar1, Ar4 are selected from hydrogen, benzene, biphenyl;

m, n are selected from 0, 1, 2, 3, 4, 5; and m+n is greater than or equal to 1; and n is selected from 0: m is selected from 2, 3, 4, 5, Ar1 is selected from benzene, or m is selected from 1, and Ar1 is selected from biphenyl;

Ar2, Ar3 are independently selected from X, Y, Z, and at least one of Ar2 and Ar3 is selected from one of Y and Z;

R1 and R2 are selected from substituted or unsubstituted alkyl groups of 1 to 6 carbon atoms, substituted or unsubstituted aryl groups of 6 to 13 carbon atoms, and R1 and R2 can be linked to form a ring through a single bond;

Formula (I) may be substituted by one or more Rs, R is selected from deuterium, F, CN, substituted or unsubstituted alkyl of 1 to 6 carbon atoms, substituted or unsubstituted of 6 to 13 carbon atoms aryl;

The following compounds are not included:

Further, at least one of Ar2 and Ar3 is selected from Y-1, Y-2, Z-1, Z-2:

Further, Ar2 is selected from Y-1, Y-2, Z-1, Z-2, and Ar3 is selected from X.

Further, Ar2 and Ar3 are selected from Y-1, Y-2, Z-1 and Z-2.

Further, Ar2 and Ar3 are selected from Y-1, Y-2, Z-1 and Z-2, and Ar2 and Ar3 are different.

Further, m is selected from 0, and n is selected from 1.

Further, m is selected from 1, and n is selected from 1.

Further, one of m and n is selected from 2, and the other is selected from 0.

Further, R1 and R2 are selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, and biphenyl.

Further, the benzofluorene compound is selected from one of the following structures and its isomers:

The isomers refer to:

In the specific structures listed above, the substituent Ar1 of the benzene ring on the N atom of the carbazole ring is connected at a specific position, in formula X, Ar4 is also connected at a specific position corresponding to the benzene ring, when Ar1 and Ar4 are selected from biphenyl When the base is attached, the two phenyl rings of the biphenyl are also connected at specific positions.

For the above specific structure, any possible connection of Ar1 on the benzene ring and/or any possible connection of Ar4 on the benzene ring and/or when Ar1 and Ar4 are selected from biphenyl, the two benzene rings of the biphenyl are any Structures formed by possible linkages, defined as isomers of compounds 1-60 above, are also within the scope of the present invention.

An example is as follows:

The structure of compound 3 is as follows:

Its isomers include the following two structures:

The structure of compound 13 is as follows:

Its isomers include but are not limited to the following structures:

Isomers of other compounds can be understood with reference to the above textual explanations and specific examples.

An organic electroluminescence device comprising the benzofluorene compound described in this application.

Further, the host material of the hole transport layer or the light emitting layer of the organic electroluminescent device is the compound of the present application.

A display device includes the organic electroluminescence device provided in the present application.

Adopt the technical scheme of the present application, the beneficial effect that produces is as follows:

The compound represented by the formula (I) of the present application is a new compound, which can be used in organic electroluminescence devices, as HTL and Host materials.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

It should be noted that: in this application, if there is no special description, all the embodiments and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution. In this application, unless otherwise specified, all the technical features and preferred features mentioned herein can be combined with each other to form a new technical solution. In this application, unless otherwise specified, percentage (%) or part refers to the weight percentage or weight part relative to the composition. In this application, if there is no special description, the involved components or their preferred components can be combined with each other to form a new technical solution. In this application, unless otherwise stated, the numerical range "a-b" represents an abbreviated representation of any combination of real numbers between a and b, where both a and b are real numbers. For example, the numerical range "6-22" indicates that all real numbers between "6-22" have been listed in this document, and "6-22" is just an abbreviated representation of the combination of these numerical values. The disclosure of a "range" herein, in the form of a lower limit and an upper limit, may be one or more lower limits, and one or more upper limits, respectively. In the present application, unless otherwise stated, each reaction or operation step may be performed sequentially or out of sequence. Preferably, the reaction methods herein are performed sequentially.

Unless otherwise defined, professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods or materials similar or equivalent to those described can also be used in the present application.

Synthesis Example 1 Synthesis of Compound 3

The synthetic route of compound 3 is as follows:

500 ml there-neck flask, nitrogen protection, add 350 ml of dry toluene, 4.87 g (0.01 mol) compound shown in M-1, 3.55 g (0.011 mol) 9-bromo-11,11-dimethyl-11H-benzo [a] Fluorene, 0.0575 g (0.0001 mol) Pd(dba)2 (palladium bis-dibenzylideneacetone), 0.4 g (0.0002 mol) 10% tri-tert-butylphosphine in toluene, 1.44 g (0.015 mol) Sodium tert-butoxide, heated to reflux for 12 hours, cooled, added water and liquid, the organic layer was washed with water until neutral, dried over magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, separated by silica gel column chromatography, petroleum ether: ethyl acetate Elution of ester=9:1 (volume ratio) gave 4.19 g of the compound shown in 3.

The compound shown in 3 was detected by mass spectrometry, and the molecular m/z was determined to be: 728.

The compounds shown in 3 were detected by NMR, and the data were analyzed as follows:

1H-NMR (Bruker, Switzerland, AvanceⅡ400MHz nuclear magnetic resonance spectrometer, CDCl3): δ8.57 (m, 1H), δ8.22～8.18 (m, 2H), δ8.13～8.04 (m, 2H), δ7. 96(m, 1H), δ7.77(m, 2H), δ7.72(d, 1H), δ7.66～7.34(m, 23H), δ7.20～7.08(m, 2H), δ1.83 (s, 6H).

Synthesis Example 2 Synthesis of Compound 5

(1) Synthesis of intermediate M-2

250 ml three-necked flask, nitrogen protection, add 100 ml of dry toluene, 4.74 g of 9-([1,1'-biphenyl]-4-yl)-3-(4-bromophenyl)-9H-carbazole, 1.69 g of 4-aminobiphenyl, 0.0575 g of Pd(dba)2 (palladium bis-dibenzylideneacetone), 0.4 g of 10% tri-tert-butylphosphine in toluene, 1.44 g of sodium tert-butoxide, heated to 60°C The reaction was carried out for 12 hours, cooled, and water was added. The organic layer was washed with water until neutral, dried over magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, and crystallized from a mixed solvent of toluene and ethanol to obtain 3.8 g of the compound shown in M-2.

The compound shown in M-2 was detected by mass spectrometry, and the molecular m/z was determined to be: 562.

(2) Synthesis of compound 5

Referring to the synthesis of compound 3 in Example 1, the compound shown in M-1 was replaced with the compound shown in M-2, and the 9-bromo-11,11-dimethyl-11H-benzo[a ]fluorene was replaced by 2-bromo-11,11-dimethyl-11H-benzo[b]fluorene to give compound 5.

The compound 5 was detected by mass spectrometry, and the molecular m/z was determined to be: 804.

Synthesis Example 3 Synthesis of Compound 17

(1) Synthesis of intermediate M-3

Referring to the synthesis of the intermediate M-2 in Example 2, except that 4-aminobiphenyl is replaced with 3,5-diphenylaniline, M-3 is obtained.

The compound shown in M-3 was detected by mass spectrometry, and the molecular m/z was determined to be: 638.

(2) Synthesis of compound 17

Referring to the synthesis of compound 3 in Example 1, the compound shown in M-1 was replaced with the compound shown in M-3, and the 9-bromo-11,11-dimethyl-11H-benzo[a ]fluorene was replaced by 2-bromo-11,11-dimethyl-11H-benzo[b]fluorene to give compound 17.

The compound 17 was detected by mass spectrometry, and the molecular m/z was determined to be: 880.

Synthesis Example 4 Synthesis of Compound 41

250 ml there-neck flask, nitrogen protection, add 50 ml of dry toluene, 3.34 g (0.01mol) 4-(9-phenyl-9H-carbazol-3-yl)aniline, 7.1 g (0.022mol) 9-bromo- 11,11-Dimethyl-11H-benzo[a]fluorene, 0.0575 g (0.0001 mol) Pd(dba)2 (bisdibenzylideneacetone palladium), 0.4 g (0.0002 mol) containing 10% tri-tert-butyl The toluene solution of phosphine, 1.44 g (0.015 mol) of sodium tert-butoxide, heated to reflux for 18 hours, cooled, filtered after adding water, the obtained solid was washed with water until neutral, and separated by silica gel column chromatography after drying, and petroleum ether: Elution with ethyl acetate=9:1 (volume ratio) gave 6.5 g of the compound shown in 41.

The compound shown in 41 was detected by mass spectrometry, and the molecular m/z was determined to be: 818.

Synthesis Example 5 Synthesis of Compound 43

(1) Synthesis of intermediate M-4

250 ml there-necked flask, nitrogen protection, add 120 ml of dry toluene, 3.34 g (0.01mol) 4-(9-phenyl-9H-carbazol-3-yl)aniline, 3.22 (0.01mol) 9-bromo-11 , 11-Dimethyl-11H-benzo[a]fluorene, 0.0575 g (0.0001 mol) Pd(dba)2 (bisdibenzylideneacetone palladium), 0.4 g (0.0002 mol) containing 10% tri-tert-butyl The toluene solution of phosphine, 1.44 g (0.015 mol) of sodium tert-butoxide, heated to 60°C for 12 hours, cooled, added with water, the organic layer was washed with water until neutral, dried over magnesium sulfate, filtered to remove magnesium sulfate, and concentrated to dryness , toluene and ethanol mixed solvent to crystallize to obtain 3.11 g of the compound shown in M-4.

The compound shown in M-4 was detected by mass spectrometry, and the molecular m/z was determined to be: 576.

(2) Synthesis of compound 43

Referring to the synthesis of compound 3 in Example 1, the compound shown in M-1 was replaced with the compound shown in M-4, and the 9-bromo-11,11-dimethyl-11H-benzo[a ]fluorene was replaced by 2-bromo-11,11-dimethyl-11H-benzo[b]fluorene to give compound 43.

The compound 43 was detected by mass spectrometry, and the molecular m/z was determined to be: 818.

The synthesis of the products not listed in the above synthesis examples can be obtained by using methods known in the technical field and conventional means.

Device Embodiment

The specific structures of several materials used in this application are as follows:

Device Example 1

In the examples, the compounds of the present application are used as hole transport materials in organic electroluminescent devices, and HT-1, HT-2, and HT-3 are respectively selected as hole transport materials in organic electroluminescent devices in comparative examples.

The structure of the organic electroluminescent device is: ITO/hole transport material(20nm)/GH1(30nm):Ir(piq)3[5%]/TPBI(10nm)/Alq3(15nm)/LiF(0.5nm)/ Al (150 nm). "Ir(piq)3 [5%]" refers to the doping ratio of green-red dye, that is, the weight ratio of the red host material GH1 to Ir(piq)3 is 100:5.

The preparation process of the organic electroluminescent device is as follows: the glass plate coated with the ITO transparent conductive layer is ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreasing in an acetone:ethanol mixed solvent, and dried in a clean environment. Bake until moisture is completely removed, rinse with UV light and ozone, and bombard the surface with a low-energy cation beam;

The above-mentioned glass substrate with anode was placed in a vacuum chamber, evacuated to 1 × 10 ^-5 to 9 × 10 ^-3 Pa, and the comparative material and the material of the present invention were respectively vacuum-evaporated on the above-mentioned anode layer film as a vacuum. The hole transport layer, the evaporation rate is 0.1nm/s, and the evaporation film thickness is 20nm;

The red host material GH1 and the dye Ir(piq)3 were vacuum-deposited on the hole transport layer to serve as the light-emitting layer of the organic electroluminescent device. The evaporation rate was 0.1 nm/s, and the total film thickness was 30 nm. The weight ratio of red light host material GH1 to Ir(piq)3 is 100:5;

The electron transport layers TPBI and Alq3 were vacuum evaporated on top of the light-emitting layer in turn, the evaporation rate was 0.1nm/s, and the evaporation film thickness was 10nm and 15nm respectively;

LiF of 0.5 nm was vacuum evaporated on the electron transport layer, and Al of 150 nm was used as the electron injection layer and cathode.

All organic electroluminescent devices are prepared by the above method, the difference only lies in the selection of hole transport materials, as detailed in Table 1 below.

Performance Testing:

The brightness, driving voltage, current efficiency, and LT95 of the prepared organic electroluminescent devices were measured using the OLED-1000 multi-channel accelerated aging life and light-color performance analysis system produced by Hangzhou Yuanfang. The test results are shown in the following table. Lifetime data LT95 refers to the time (hours) required for the brightness to decrease to 95% of the initial brightness at room temperature (25-27°C) with the current density unchanged (here, 1000 cd/m ² ) at the initial brightness.

Table 1

hole transport material	Required brightness cd/m 2	drive voltage V	Current efficiency cd/A	LT95 hours
HT-1	1000	6.12.	28.01	17
HT-2	1000	6.33	26.11	16
HT-3	1000	6.35	25.09	twenty two
1	1000	5.63	28.11	35
3	1000	5.55	29.26	38
5	1000	5.70	28.88	40
11	1000	5.61	28.99	39
17	1000	5.55	30.28	61
20	1000	5.49	31.11	66
twenty one	1000	5.39	32.10	65
41	1000	5.21	29.12	69
43	1000	5.33	31.15	102
53	1000	5.19	29.55	71
57	1000	4.46	36.62	16
58	1000	4.18	38.13	18
61	1000	5.79	26.32	36

As can be seen from the above table, compared with the comparative compounds, the compounds provided by the present application can improve the luminous efficiency, reduce the driving voltage, and improve the lifespan as the hole material transport of the organic electroluminescent device.

Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Device Example 2

In the examples, the compounds of the present application were selected as the green light host materials in the organic electroluminescent devices, and GH1 and HT-3 were selected as the green light host materials in the organic electroluminescent devices in the comparative examples.

The structure of the organic electroluminescent device is: ITO/Compound 5(30nm)/Green host material(30nm): Ir(ppy)3[7%]/TPBI(10nm)/Alq3(15nm)/LiF(0.5nm) /Al (150 nm). The 7% in "Ir(ppy)3 [7%]" refers to the doping ratio of the green dye, that is, the weight ratio of the green host material to Ir(ppy)3 is 100:7.

The preparation process of the organic electroluminescent device is as follows: the glass plate coated with the ITO transparent conductive layer is ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreasing in an acetone:ethanol mixed solvent, and dried in a clean environment. Bake until moisture is completely removed, rinse with UV light and ozone, and bombard the surface with a low-energy cation beam;

The above-mentioned glass substrate with anode is placed in a vacuum chamber, and the vacuum is evacuated to 1 × 10 ^-5 to 9 × 10 ^-3 Pa, and a hole transport layer of the present invention compound 5 is vacuum-evaporated on the above-mentioned anode layer film, and then evaporated. The plating rate is 0.1nm/s, and the evaporation film thickness is 30nm;

The green light host material and dye Ir(ppy)3 were vacuum-evaporated on the hole transport layer as the light-emitting layer of the organic electroluminescent device. The evaporation rate was 0.1 nm/s, and the total film thickness was 30 nm. The green light host material is selected from the compound of the present invention and the comparative materials GH1 and HT-3 respectively;

The electron transport layers TPBI and Alq3 were vacuum evaporated on top of the light-emitting layer in turn, the evaporation rate was 0.1nm/s, and the evaporation film thickness was 10nm and 15nm respectively;

LiF of 0.5 nm was vacuum evaporated on the electron transport layer, and Al of 150 nm was used as the electron injection layer and cathode.

All organic electroluminescent devices are prepared by the above method, the difference is only in the choice of the green light host material, as detailed in Table 2 below.

Performance Testing:

The brightness, driving voltage, and current efficiency of the prepared organic electroluminescent devices were measured using the OLED-1000 multi-channel accelerated aging life and light-color performance analysis system produced by Hangzhou Yuanfang. The test results are shown in Table 2 below.

Table 2

Green light host material	Required brightness cd/m2	drive voltage V	Current efficiency cd/A
GH1	1000	5.16	26.11
HT-3	1000	8.66	11.34
19	1000	5.10	31.11
32	1000	4.48	30.26
41	1000	4.69	32.87
56	1000	4.92	33.19

It can be seen from the data in Table 2 that, compared with the compounds of the comparative example, the use of the compounds provided by the present application as the green light host material of the organic electroluminescent device can significantly improve the current efficiency of the organic electroluminescent device, effectively reduce the drive voltage.

Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims (10)

1. A benzofluorene compound, characterized in that the structural formula of the compound is shown in formula (I),

   

   Wherein, Ar1, Ar4 are selected from hydrogen, benzene, biphenyl;

   m, n are selected from 0, 1, 2, 3, 4, 5; and when m+n is greater than or equal to 1, and n is selected from 0: m is selected from 2, 3, 4, 5, Ar1 is selected from benzene, or m is selected from 1, and Ar1 is selected from biphenyl;

   Ar2, Ar3 are independently selected from X, Y, Z, and at least one of Ar2 and Ar3 is selected from one of Y and Z;

   R1 and R2 are selected from substituted or unsubstituted alkyl groups of 1 to 6 carbon atoms, substituted or unsubstituted aryl groups of 6 to 13 carbon atoms, and R1 and R2 can be linked to form a ring through a single bond;

   Formula (I) may be substituted by one or more Rs, R is selected from deuterium, F, CN, substituted or unsubstituted alkyl of 1 to 6 carbon atoms, substituted or unsubstituted of 6 to 13 carbon atoms aryl;

   The following compounds are not included:

   
2. According to the compound of claim 1, at least one of Ar2 and Ar3 is selected from Y-1, Y-2, Z-1, Z-2:

   
3. According to the compound of claim 1, Ar2 is selected from Y-1, Y-2, Z-1, Z-2, and Ar3 is selected from X.
4. According to the compound of claim 1, Ar2 and Ar3 are selected from Y-1, Y-2, Z-1 and Z-2, and Ar2 and Ar3 are different.
5. The compound according to claim 1, wherein m is selected from 0 and n is selected from 1.
6. According to the compound of claim 1, m is selected from 1, and n is selected from 1.
7. According to the compound of claim 1, one of m and n is selected from 2, and the other is selected from 0.
8. According to the compound of claim 1, R1 and R2 are selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, and biphenyl.
9. The compound according to claim 1 is selected from the following compounds 1-62 and isomers of compounds 1-62:

   

   

   

   

   
10. An organic electroluminescence device, comprising the compound of any one of claims 1-9.