CN112259691B

CN112259691B - Organic electroluminescent device

Info

Publication number: CN112259691B
Application number: CN202011533663.1A
Authority: CN
Inventors: 钱超; 许军
Original assignee: Nanjing Topto Materials Co Ltd
Current assignee: Nanjing Topto Materials Co Ltd
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2021-10-22
Anticipated expiration: 2040-12-23
Also published as: CN112259691A

Abstract

The invention disclosesAn organic electroluminescent device comprising an anode, a cathode and a light-emitting layer disposed between the anode and the cathode; a hole transport region including at least one selected from a hole injection layer, a hole transport layer, a hole transition layer, and an electron blocking layer between the anode and the light emitting layer; an electron transport region including at least one layer selected from a hole blocking layer, an electron transition layer, an electron transport layer, and an electron injection layer between the light emitting layer and the cathode; the luminescent layer contains the following A-type compounds:

at least one layer of the hole transport region contains a compound represented by chemical formula 1:

according to the organic electroluminescent device designed by the invention, the transition layer (BL) is introduced, so that the luminous efficiency is greatly improved under the same current density, the starting voltage of the device is reduced, the power consumption of the device is relatively reduced, and the service life of the device is correspondingly prolonged.

Description

Organic electroluminescent device

Technical Field

The invention relates to the technical field of organic electroluminescence, in particular to an organic electroluminescent device.

Background

An OLED (organic light-Emitting Diode), also called an organic electroluminescent Display, an organic light-Emitting semiconductor (OLED). The OLED is a current-type organic light emitting device, and emits light by injection and recombination of carriers, and the intensity of light emission is proportional to the injected current. Under the action of an electric field, holes generated by an anode and electrons generated by a cathode move, are respectively injected into a hole transport layer and an electron transport layer, and migrate to a light emitting layer. When the two meet at the light emitting layer, energy excitons are generated, thereby exciting the light emitting molecules to finally generate visible light.

At present, the structure of the OLED device generally comprises a substrate, a cathode, an anode, a Hole Injection Layer (HIL), an Electron Injection Layer (EIL), a Hole Transport Layer (HTL), an Electron Transport Layer (ETL), an Electron Blocking Layer (EBL), a Hole Blocking Layer (HBL), an emission layer (EML), and the like, and the improvement of the light emitting performance of the OLED device needs to be started from materials, and the structure of the OLED device needs to be innovated.

Disclosure of Invention

The purpose of the invention is as follows: in order to solve the technical problems, the invention provides a compound and an organic electroluminescent device.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:

an organic electroluminescent device comprising:

an anode; a cathode; and a light-emitting layer disposed between the anode and the cathode;

a hole transport region including at least one selected from a hole injection layer, a hole transport layer, a hole transition layer, and an electron blocking layer between the anode and the light emitting layer;

an electron transport region comprising at least one layer selected from a hole blocking layer, an electron transition layer, an electron transport layer, and an electron injection layer between the light emitting layer and the cathode;

the luminescent layer contains A compounds, and the A compounds are shown as follows:

；

at least one layer of the hole transport region contains a compound represented by the following chemical formula 1:

wherein, L1 and L2 are single bonds or phenylene;

r1 and R2 are the same or different and are each independently C6-C30 aromatic hydrocarbon groups;

x is O or S;

m and n are respectively 0, 1 and 2 independently.

Further, the light-emitting layer also contains a B-type compound with the following structural formula:

further, the mass ratio of the A-type compound to the B-type compound is 6: 4.

Further, R1 and R2 in the chemical formula 1 are the same or different and are each independently phenyl, biphenyl, terphenyl.

Further, the compound of formula 1 is any one of the following structural formula:

further, the hole transition layer contains a compound represented by chemical formula 1.

The room temperature of the invention is 25 +/-5 ℃.

The invention has the beneficial effects that:

firstly, the A-type compound in the device designed by the invention is an N-type green phosphorescent main body material (GH), and the A-type compound and the B-type compound as a P-type green phosphorescent main body material (GH) have good fusion property, so that the stability, the luminous efficiency and the yield of the device prepared by using the two materials as luminous main body components are effectively improved, and meanwhile, the A-type compound has a very low refractive index, so that the light-emitting rate of the device can be effectively improved, and the luminous efficiency of the device is further improved.

Secondly, in order to further improve the luminous efficiency and the service life of the device, a brand new hole transition layer (BL) is introduced under the existing device structure, and the compound shown in chemical formula 1 is used as the material of the hole transition layer (BL), so that the transmission rate and the migration path of holes can be effectively adjusted, the recombination region of the holes and electrons can be accurately controlled at the middle position of the luminous layer, and the luminous efficiency of the device is greatly improved. Meanwhile, the HOMO energy level of the functional layer material is between a Hole Transport Layer (HTL) and an electron blocking layer, and holes can smoothly migrate from the hole transport layer to the electron blocking layer after passing through a transition layer and reach a light emitting layer to be combined with electrons to generate excitons. The device manufactured by using the A-type compound, the B-type compound and the compound of the chemical formula 1 designed by the invention can effectively improve the yield of mass production of OLED panels and reduce the energy consumption of the OLED panels.

Drawings

Fig. 1 is a schematic structural diagram of an organic electroluminescent device provided by the present invention;

the reference numbers in the figures represent respectively:

1-anode, 2-hole injection layer, 3-hole transmission layer, 4-hole transition layer, 5-electron barrier layer, 6-luminous layer, 7-hole barrier layer, 8-electron transition layer, 9-electron transmission layer, 10-electron injection layer and 11-cathode.

FIG. 2 is a graph showing the life of organic electroluminescent devices prepared in comparative example 1 and comparative example 2 of the present invention;

as can be seen from fig. 2, T97% lifetimes of the organic electroluminescent devices prepared in comparative example 1 and comparative example 2 of the present invention were 493h and 436h, respectively.

FIG. 3 is a graph showing the life of organic electroluminescent devices prepared in comparative examples 1 and 6 of the present invention;

as can be seen from fig. 3, T97% lifetimes of the organic electroluminescent devices prepared in comparative example 1 and comparative example 6 according to the present invention were 493h and 532h, respectively.

Detailed Description

Embodiments of the various aspects are further illustrated and described below. It should be understood that the description herein is not intended to limit the claims to the particular aspects described. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the disclosure as defined by the appended claims.

As used herein, a "Ca to Cb" hydrocarbyl group is defined as having a carbon number from "a" (inclusive) to "b" (inclusive)

A hydrocarbon group of (1). As used herein, "a and/or b" means "a" or "b" or "a and b".

As used herein, in "substituted" or "unsubstituted," the term "substituted" means that at least one hydrogen in the group is re-coordinated to deuterium, a hydrocarbon group, a hydrocarbon derivative group, a halogen, or a cyano (-CN). The term "unsubstituted" means that at least one hydrogen in the group does not re-coordinate with deuterium, a hydrocarbon group, a hydrocarbon derivative group, a halogen, or a cyano (-CN) group. Examples of the hydrocarbon group or hydrocarbon derivative group may include C1 to C30 alkyl groups, C2 to C30 alkenyl groups, C2 to C30 alkynyl groups, C6 to C30 aryl groups, C5 to C30 heteroaryl groups, C1 to C30 alkylamino groups, C6 to C30 arylamino groups, C6 to C30 heteroarylamino groups, C6 to C30 arylheteroarylamino groups, and the like, but are not limited thereto.

The alkyl of C1-C4 in the invention refers to methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl; deuterated alkyl of C1-C4 is a group obtained by replacing any number of hydrogens in methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and tert-butyl with deuterium.

The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Example 1:

the preparation of compound A-1 is shown below:

under the protection of nitrogen, adding compound 1-a (10 g, 356.81g/mol, 28.03 mmol), compound 1-b (1.1 eq, 9.04g, 293.14g/mol, 30.83 mmol) and sodium carbonate (2 eq, 5.94g, 105.99g/mol, 56.06 mmol) into toluene (200 ml), ethanol (100 ml) and water (100 ml), stirring and mixing uniformly, adding tetrakistriphenylphosphine palladium (0.05 eq, 1.62g, 1155.58g/mol, 1.4 mmol), heating to reflux reaction for 10h, cooling to room temperature, adding water (100 ml), stirring to separate out an aqueous phase, extracting the aqueous phase with dichloromethane, mixing the organic phase, drying with anhydrous sodium sulfate, stirring and purifying with silica gel to obtain compound A-1 (12.79 g, yield 80.1%), ESI-MS (M/z) (M +): theoretical 569.66, found 570.19, elemental analysis result (molecular formula C39H19D5N 4O): theoretical C, 82.23, H, 5.13, N, 9.84, O, 2.81; found C, 82.23, H, 5.13, N, 9.84, O, 2.81.

Example 2:

the preparation of compound A-2 is shown below:

the preparation method was substantially the same as in example 1 except that the compound 1-a was replaced with the compound 2-a to obtain the compound a-2 (yield 72.1%), ESI-MS (M/z) (M +): theoretical 645.76, found 646.88, elemental analysis result (molecular formula C45H23D5N 4O): theoretical value C, 83.70, H, 5.15, N, 8.68, O, 2.48; found C, 83.70, H, 5.15, N, 8.68, O, 2.48.

Example 3:

the preparation of compound A-3 is shown below:

the preparation method was substantially the same as in example 1 except that the compound 3-a was used instead of the compound 1-a to obtain a compound a-3 (yield 71.5%), ESI-MS (M/z) (M +): theoretical 645.76, found 646.62, elemental analysis result (molecular formula C45H23D5N 4O): theoretical value C, 83.70, H, 5.15, N, 8.68, O, 2.48; found C, 83.71, H, 5.14, N, 8.68, O, 2.48.

Example 4:

the preparation of compound A-4 is shown below:

the preparation method was substantially the same as in example 1 except that the compound 1-a was replaced with the compound 4-a, respectively, and the reaction gave the compound a-4 (yield 79.7%), ESI-MS (M/z) (M +): theoretical 645.76, found 646.27, elemental analysis result (molecular formula C39H19D5N 4O): theoretical C, 82.23, H, 5.13, N, 9.84, O, 2.81; found C, 82.23, H, 5.13, N, 9.84, O, 2.81.

Example 5:

the synthesis method of the compound BL-1 is as follows:

under the protection of nitrogen, compound 5-a (4 g, 487.39g/mol, 8.21 mmol), compound 5-b (1 eq, 2.64g, 321.41g/mol, 8.21 mmol), sodium tert-butoxide (1.1 eq, 0.87g, 96.1g/mol, 9.03 mmol), tris (dibenzylideneacetone) dipalladium (0.05 eq, 0.38g, 915g/mol, 0.41 mmol), tri-tert-butylphosphine (0.05 eq, 0.083g, 202.32g/mol, 0.41 mmol), toluene (40 ml) were added to a reaction flask, heating to reflux reaction for 5h after the addition is finished, cooling to room temperature after the reaction is finished, adding water (40 ml), stirring for 15min, filtering to obtain a filtrate, filtering the filtrate through diatomite, separating liquid to obtain an organic phase, drying the organic phase through anhydrous magnesium sulfate, spin-drying, and purifying by column chromatography to obtain a compound BL-1 (3.85 g, yield 64.4%), ESI-MS (M/z) (M +): theoretical 727.89, found 727.56, elemental analysis result (molecular formula C55H37 NO): theoretical C, 90.75, H, 5.12, N, 1.92, O, 2.20; found C, 90.75, H, 5.12, N, 1.92, O, 2.20.

Example 6:

the synthesis method of the compound BL-2 is as follows:

the preparation method was substantially the same as in example 5 except that the compound 5-b was replaced with the compound 6-b to obtain the compound BL-2 (yield 63.7%), ESI-MS (M/z) (M +): theoretical 727.89, found 727.44, elemental analysis result (molecular formula C55H37 NO): theoretical C, 90.75, H, 5.12, N, 1.92, O, 2.20; found C, 90.75, H, 5.12, N, 1.92, O, 2.20.

Example 7:

the synthesis method of the compound BL-5 is as follows:

the preparation method was substantially the same as in example 5 except that the compound 7-a was used instead of the compound 5-a, and the reaction gave the compound BL-5 (yield 65.1%), ESI-MS (M/z) (M +): theoretical 727.89, found 727.21, elemental analysis result (molecular formula C55H37 NO): theoretical C, 90.75, H, 5.12, N, 1.92, O, 2.20; found C, 90.75, H, 5.12, N, 1.92, O, 2.20.

Example 8:

the synthesis method of the compound BL-7 is as follows:

the preparation method was substantially the same as in example 7 except that the compound 7-b was replaced with the compound 8-b to obtain the compound BL-7 (yield 60.9%), ESI-MS (M/z) (M +): theoretical 727.89, found 727.33, elemental analysis result (molecular formula C55H37 NO): theoretical C, 90.75, H, 5.12, N, 1.92, O, 2.20; found C, 90.75, H, 5.11, N, 1.92, O, 2.20.

Example 9:

the synthesis method of the compound BL-8 is as follows:

the preparation method was substantially the same as in example 7 except that the compound 7-b was replaced with the compound 9-b to obtain the compound BL-8 (yield 65.4%), ESI-MS (M/z) (M +): theoretical 727.89, found 727.91, elemental analysis result (molecular formula C55H37 NO): theoretical C, 90.75, H, 5.12, N, 1.92, O, 2.20; found C, 90.75, H, 5.12, N, 1.92, O, 2.20.

Example 10:

the synthesis method of the compound BL-9 is as follows:

the preparation method was substantially the same as in example 5 except that the compound 5-a was replaced with the compound 10-a to obtain the compound BL-9 (yield 64.1%), ESI-MS (M/z) (M +): theoretical 743.95, found 743.80, elemental analysis result (molecular formula C55H37 NS): theoretical C, 88.79, H, 5.01, N, 1.88, S, 4.31; found C, 88.79, H, 5.01, N, 1.88, S, 4.31.

Example 11:

the synthesis method of the compound BL-10 is as follows:

the preparation method was substantially the same as in example 10, except that the compound 11-b was used instead of the compound 10-b, and the reaction gave the compound BL-10 (yield 63.9%), ESI-MS (M/z) (M +): theoretical 743.95, found 743.90, elemental analysis result (molecular formula C55H37 NS): theoretical C, 88.79, H, 5.01, N, 1.88, S, 4.31; found C, 88.79, H, 5.01, N, 1.88, S, 4.31.

Example 12:

the synthesis method of the compound BL-11 is as follows:

the preparation method was substantially the same as in example 10, except that the compound 12-b was used instead of the compound 10-b, and the reaction gave the compound BL-11 (yield 61.5%), ESI-MS (M/z) (M +): theoretical 743.95, found 743.94, elemental analysis result (molecular formula C55H37 NS): theoretical C, 88.79, H, 5.01, N, 1.88, S, 4.31; found C, 88.79, H, 5.01, N, 1.88, S, 4.30.

Example 13:

the synthesis method of the compound BL-13 is as follows:

the preparation method was substantially the same as in example 10, except that the compound 10-a was replaced with the compound 13-a, and the reaction gave the compound BL-13 (yield 64.7%), ESI-MS (M/z) (M +): theoretical 743.95, found 743.66, elemental analysis result (molecular formula C55H37 NS): theoretical C, 88.79, H, 5.01, N, 1.88, S, 4.31; found C, 88.79, H, 5.01, N, 1.88, S, 4.31.

Example 14:

the synthesis method of the compound BL-14 is as follows:

the preparation method was substantially the same as in example 13, except that the compound 14-b was used instead of the compound 13-b, and the reaction gave the compound BL-14 (yield 62.9%), ESI-MS (M/z) (M +): theoretical 743.95, found 743.59, elemental analysis result (molecular formula C55H37 NS): theoretical C, 88.79, H, 5.01, N, 1.88, S, 4.31; found C, 88.79, H, 5.01, N, 1.88, S, 4.31.

Example 15:

the synthesis method of the compound BL-16 is as follows:

the preparation method was substantially the same as in example 13, except that the compound 13-b was replaced with the compound 15-b, and the reaction gave the compound BL-16 (yield 64.0%), ESI-MS (M/z) (M +): theoretical 743.95, found 743.80, elemental analysis result (molecular formula C55H37 NS): theoretical C, 88.79, H, 5.01, N, 1.88, S, 4.31; found C, 88.79, H, 5.01, N, 1.88, S, 4.31.

Testing the performance of the device:

application example 1:

adopting ITO as the anode substrate material of the reflecting layer, and sequentially using water, acetone and N₂Carrying out surface treatment on the glass substrate by plasma;

depositing a HT-1 material doped with 5% HAT-CN with a thickness of 10nm above the ITO anode substrate to form a Hole Injection Layer (HIL);

evaporating HT-1 above the Hole Injection Layer (HIL) to form a Hole Transport Layer (HTL) with the thickness of 120 nm;

evaporating a compound BL-1 above the Hole Transport Layer (HTL) to form a transition layer (BL) with a thickness of 30 nm;

evaporating a compound EB-1 above the transition layer (BL) to form an Electron Blocking Layer (EBL) with the thickness of 10 nm;

a-1 prepared in the embodiment 1 of the invention is used as an N-type main body material, B-1 is used as a P-type main body material, the mass ratio of the A-1 to the B-1 is 6:4, and GD-1 is used as a doping material (GD-1 is 5 percent of the total weight of the N-type main body material and the P-type main body material) to be evaporated at different rates to form a light-emitting layer with the thickness of 30nm on an Electron Blocking Layer (EBL);

mixing ET-1 with LiQ according to the proportion of 5: 5 is evaporated on the luminescent layer together by mass ratio to obtain an Electron Transport Layer (ETL) with the thickness of 35 nm;

mixing magnesium (Mg) and silver (Ag) at a ratio of 9:1, and evaporating to obtain an Electron Injection Layer (EIL) with a thickness of 15nm formed above the Electron Transport Layer (ETL);

thereafter, silver (Ag) was evaporated over the electron transport layer (EIL) to form a cathode having a thickness of 100nm, DNTPD having a thickness of 50nm was deposited on the above-mentioned cathode sealing layer, and further, the surface of the cathode was sealed with a UV hardening adhesive and a sealing film (seal cap) containing a moisture scavenger to protect the organic electroluminescent device from atmospheric oxygen or moisture, thereby preparing an organic electroluminescent device.

Application examples 2 to 4

The compounds a-2, a-3 and a-4 of examples 2 to 4 of the present invention were used as N-type host materials, and the other portions were the same as in application example 1, whereby organic electroluminescent devices of application examples 2 to 4 were produced.

Comparative example 1:

the difference from application example 1 is that the transition layer (BL) is eliminated, and the rest is the same as application example 1.

Comparative examples 2 to 5:

the difference from application example 1 is that the transition layer (BL) is eliminated, and the compounds C-1, C-2, C-3 and C-4 in Chinese patent CN110741064A are used as N-type host materials, and the rest is the same as application example 1.

Comparative examples 6 to 15:

the difference from application example 1 is that BL-2, BL-5, BL-7, BL-8, BL-9, BL-10, BL-11, BL-13, BL-14 and BL-16 are respectively used to replace the compound BL-1 in application example 1, and the rest is the same as application example 1.

The characteristics of the organic electroluminescent element manufactured in the above application example and the organic electroluminescent element manufactured in the comparative example were that the current density was 10mA/cm²The results of measurements under the conditions of (1) are shown in Table 1.

Table 1:

as can be seen from table 1 above, the organic electroluminescent device designed by the present invention has the advantages that by introducing the transition layer (BL), the light emitting efficiency is greatly improved under the same current density, the start voltage of the device is reduced, the power consumption of the device is relatively reduced, and the lifetime of the device is correspondingly improved.

In addition, the organic electroluminescent devices prepared in comparative examples 1 to 10 and application examples 1 to 4 were subjected to a light emission life test to obtain light emission life T97% data (time for which the light emission luminance was reduced to 97% of the initial luminance), and the test equipment was a TEO light emitting device life test system. The results are shown in table 2:

table 2:

as can be seen from table 2 above, the organic electroluminescent device designed by the present invention has a corresponding improvement in the light emitting lifetime under the same current density by introducing the transition layer (BL).

Claims

1. An organic electroluminescent device, comprising:

an anode;

a cathode;

and a light-emitting layer disposed between the anode and the cathode;

a hole transport region including at least one selected from a hole injection layer, a hole transport layer, a transition layer, and an electron blocking layer between the anode and the light emitting layer;

wherein, L1 and L2 are single bonds or phenylene;

x is O or S;

m and n are respectively 0, 1 and 2 independently.

2. The organic electroluminescent device of claim 1, wherein the light-emitting layer further comprises a compound of formula B:

3. the organic electroluminescent device of claim 2, wherein the mass ratio of the group a compound to the group B compound is 6: 4.

4. The organic electroluminescent device as claimed in claim 1, wherein R1 and R2 in chemical formula 1 are the same or different and each is independently a phenyl group, a biphenyl group, or a terphenyl group.

5. The organic electroluminescent device according to claim 1, wherein the compound of formula 1 is any one of compounds of the following structural formulae:

6. the organic electroluminescent device according to claim 1, wherein the transition layer contains a compound represented by chemical formula 1.