HK1191041B - Organic electronic materials and organic electroluminescent device - Google Patents

Abstract

The present invention relates to "organic electronic materials and organic electroluminescent devices", which have a structure as described in the following formula (I) or (II).The organic electroluminescent device of the present invention uses compounds containing fluoranthene groups as electron transport materials,Having high electronic transmission and injection capabilities,Due to its excellent thermal stability and good film-forming properties,While improving the efficiency of organic electroluminescent devices,It also improves the service life of the device;Meanwhile,The organic electroluminescent device of the present invention uses compounds containing fluoranthene groups as the main phosphorescent material,Due to its high triplet energy levels,And it has good electronic transmission performance,Can effectively increase the number of electrons in the luminescent layer,Improve the efficiency of the device.

Description

Organic electronic material and organic electroluminescent device

Technical Field

The invention relates to a novel organic electronic material, which is deposited into a film through vacuum evaporation and transition and is applied to an organic light-emitting diode as an electron transmission material and a phosphorescent main body material, belonging to the technical field of organic light-emitting device display.

Technical Field

The organic electroluminescent device as a novel display technology has the unique advantages of self luminescence, wide viewing angle, low energy consumption, high efficiency, thinness, rich colors, high response speed, wide applicable temperature range, low driving voltage, capability of manufacturing flexible, bendable and transparent display panels, environmental friendliness and the like, so the organic electroluminescent device technology can be applied to flat panel displays and new generation illumination and can also be used as a backlight source of LCDs. A sandwich type double-layer device is made by Tang et al of Kodak corporation in 1987 by using vacuum thin film evaporation technology and using 8-hydroxyquinoline aluminum (Alq 3) as a light-emitting layer and triphenylamine derivative as a hole transport layer, and under the driving voltage of 10V, the luminous brightness reaches 1000cd/m²(Tang C.W., Vanslyke S.A.appl.Phys.Lett.1987,51, 913-916). This breakthrough development has attracted extensive attention in the scientific and technological field and the industrial field, and has raised the trend of research and application of organic electroluminescence. Subsequently, in 1989, the invention of the subject-object technology greatly improves the luminous efficiency and the service life of the organic electroluminescent device. In 1998, Forrest et al discovered the electrophosphorescence, broken through the theoretical limit that the quantum efficiency of organic electroluminescence is lower than 25%, and increased to 100% (Baldo M.A., Forrest S.R.Et al, Nature,1998,395, 151-.

A classical three-layer organic electroluminescent device comprises a hole transport layer, a light-emitting layer and an electron transport layer. Wherein the electron transport layer of the device is conventionally Alq₃The material has good film forming property and thermal stability, but the material emits strong green light and low electron mobility, and the industrial application of the material is influenced. Subsequently, some electron transport materials having superior properties such as TPBI, BCP, Bphen, etc. are also widely used in organic electroluminescent devices. The existing luminescent material can be divided into two types, namely a fluorescent luminescent material and a phosphorescent luminescent material, and a host-guest doping technology is often adopted. CBP (4, 4' -bis (9-carbazolyl) -biphenol) is aThe phosphorescent host material has efficient and high triplet energy levels, and when CBP is used as the host material, triplet energy can be smoothly transferred to the phosphorescent light-emitting material, so that efficient red and green materials are generated. However, these representative host materials tend to limit their utility due to their thermal stability and the short lifetime of the devices produced.

Although organic electroluminescent devices have been advanced and developed for 20 years and organic materials have been developed, there are few materials that meet the market demand and have good device efficiency and lifetime, and good performance and stability.

Fluoranthene is widely applied as an electroluminescent material and can be used as an electron transport material, a hole transport material and a luminescent material, but the reported documents do not describe the performance of a device in detail, or the efficiency of the device is lower and the stability of the device is lower.

Disclosure of Invention

The invention aims to provide a high-efficiency novel organic electron transport and phosphorescence host material synthesis, application of the high-efficiency novel organic electron transport and phosphorescence host material in a device, a high-performance organic electroluminescent device and a preparation method.

The organic electronic material has a chemical structural formula of a chemical formula (I) or a chemical formula (II):

wherein the content of the first and second substances,

R₁-R₅any four of which are hydrogen and the other is C1-C6 alkyl, C7-C24 aryl, substituted or unsubstituted with one or more substituents selected from N, O, SUnsubstituted heteroaromatic ring group, triarylsilyl group, diarylamine group, diaryloxyphosphoryl group, aromatic carbonyl group, arylthio group; or

R₁、R₃、R₅Is hydrogen, R₂、R₄Each independently is C1-C6 alkyl, C6-C24 aryl, heteroaromatic ring containing one or more groups selected from N, O, S, triarylsilyl, diarylamine, diaryloxyphosphoryl, aromatic carbonyl, arylthio;

a is independently represented by C (R)₆)₂、N(R₇)、S、O、P(R₈)、S(O)₂Or B (R)₉)，R₆-R₉Independently represent hydrogen, deuterium, C1-C6 alkyl, phenyl, C1-C6 alkylphenyl, contain one or more heteroaryl groups selected from N, O, S, or form a cyclic structure between two R6 and C.

Preferably, R₁-R₅Preference is given to fluorenyl, C1-C4 alkyl or phenyl or naphthyl-substituted five-or six-membered heteroaromatic ring radicals, diphenylamino, phenylnaphthylamino, triphenylsilyl, diphenylphosphinyl, phenylcarbonyl, phenylthio.

Wherein the five-membered or six-membered heterocyclic aromatic hydrocarbon group is carbazolyl, pyrimidinyl, pyridyl, thiazolyl, triazolyl or triazinyl.

The fluorenyl is 9, 9-dimethylfluorenyl, 9-diphenylfluorenyl, 9-xylylfluorenyl or spirofluorenyl.

The R is₁、R₂、R₄、R₅Is hydrogen.

A is preferably C (R)₆)₂、N(R₇)、S、O、S(O)₂，R₆-R₇Preferably hydrogen, methyl, phenyl or methylphenyl, or two R₆And C form a five-membered ring structure.

Preferred compounds of the invention are the following, but are not limited to these

The organic electroluminescent device comprises a substrate, an anode layer formed on the substrate, and a hole injection layer, a hole transport layer, a luminescent layer, an electron transport layer, an electron injection layer and a cathode anode which are sequentially evaporated on the anode layer.

The light emitting layer may be classified as a fluorescent light emitting layer or a phosphorescent light emitting layer.

One embodiment of the organic electroluminescent element of the present invention uses the compound of the present invention as an electron transport material;

in another embodiment of the organic electroluminescent device of the present invention, the above compound is used as a phosphorescent host material, and the guest material is preferably an organic iridium compound and an organic platinum compound;

in the organic electroluminescent device of the present invention, the above compound is used as a phosphorescent host material, and the above compound is used as an electron transport layer.

The organic electroluminescent device adopts the compound containing the fluoranthene group as the electron transport material, has higher electron transport and injection capability, and also improves the service life of the device while improving the efficiency of the organic electroluminescent device due to the good thermal stability and the good film forming property; meanwhile, the organic electroluminescent device adopts the compound containing the fluoranthene group as the main material of phosphorescence, and the organic electroluminescent device not only has higher triplet state energy level, but also has good electron transmission performance, so that the number of electrons in a light-emitting layer can be effectively increased, and the efficiency of the device is improved.

Drawings

Fig. 1 is a view showing a structure of a device of the present invention, wherein 10 is a glass substrate, 20 is an anode, 30 is a hole injection layer, 40 is a hole transport layer, 50 is a light emitting layer, 60 is an electron transport layer, 70 is an electron injection layer, and 80 is a cathode.

FIG. 2 is a drawing of Compound 46¹H NMR chart.

FIG. 3 is a drawing of Compound 36¹H NMR chart.

Figure 4 is a DSC diagram for compound 46.

Detailed Description

The present invention will be described in further detail with reference to examples.

Example 1: synthesis of Compound 43

Synthesis of intermediate 1-1

7.5g of 2-bromo-9, 9-dimethyl-fluorene, 0.15g of cuprous iodide, 0.3g of tetratriphenylphosphine palladium, triethylamine and nitrogen were added to the flask, stirring was started to dissolve the materials sufficiently, 10ml of trimethylsilylacetylene was added, and the mixture was refluxed overnight for 12 hours. The solvent was removed under reduced pressure. Water was added, extraction was carried out three times with ether, the organic phases were combined, washed three times with saturated brine, dried, filtered with suction, and concentrated to give 6.8g of product in 85% yield.

Synthesis of intermediate 1-2

To the flask were added 45ml of methanol, 50ml of dichloromethane, 5g of potassium hydroxide, 6.8g of intermediate 1-1, and the reaction was stirred for 1 hour with nitrogen. The inorganic salts were removed by filtration, the organic solvent was removed, and the filter cake was recrystallized from methanol to give 4.2g, 82% yield.

Synthesis of intermediates 1 to 3

84g of acenaphthenequinone, 72.8g of 1, 3-diphenylpropanone, 600ml of ethanol, 56g of potassium hydroxide were put in a four-necked flask, stirred, introduced with nitrogen, and refluxed for 2 hours. Cool to room temperature, filter, and rinse the filter cake with ethanol 2 times to give 130g of a black solid in 91% yield.

Synthesis of Compound 43

4.2g of intermediate 1-2 and 6.3g of intermediate 1-3, and also 60ml of diphenyl ether were added to a four-necked flask, and stirring was started, nitrogen was introduced for 10 minutes, heating reflux was started for 12 hours, cooling and filtration were carried out, and the cake was heated reflux with ethyl acetate, cooling and filtration were carried out to obtain 6.5g of a pale yellow solid with a yield of 66%.¹H NMR(400MHz,CD₂Cl₂,): calcd C of m/s of 7.56-7.74(m,9H),7.21-7.44(m,14H),7.76-7.70(m,1H),1.27(s,6H)₄₃H₃₀: 546.2, found [ M⁺]:546.5。

Example 2: synthesis of Compound 46

Synthesis of intermediate 2-1

8.0g of intermediate 2-0, 0.15g of cuprous iodide and 0.3g of tetratriphenylphosphine palladium were added to the flask, and then triethylamine was added thereto, nitrogen gas was introduced, stirring was started to sufficiently dissolve the intermediate, and then 10ml of trimethylsilylacetylene was added thereto, and the mixture was refluxed overnight for 12 hours. The solvent was removed under reduced pressure. Water was added, extraction was carried out three times with ether, the organic phases were combined, washed three times with saturated brine, dried, filtered with suction, and concentrated to give 6.8g of product in 83% yield.

Synthesis of intermediate 2-2

To the flask were added 45ml of methanol, 50ml of dichloromethane, 5g of potassium hydroxide, 7g of intermediate 2-1, and the reaction was stirred for 1 hour with introduction of nitrogen. The inorganic salts were removed by filtration, the organic solvent was removed, and the filter cake was recrystallized from methanol to give 4.0g, 70% yield.

Synthesis of Compound 46

4.0g of intermediate 2-2 and 4.2g of intermediate 1-3, 60ml of diphenyl ether were added to a four-necked flask, and stirring was started, nitrogen was introduced for 10 minutes, and heating reflux was started for 12 hours, followed by cooling, filtration, heating reflux of the cake with ethyl acetate, cooling, and filtration to obtain 7.0g of a pale yellow solid with a yield of 89%.¹H NMR(400MHz,CDCl₃,): 7.61-7,79 (m,8H), 7.47-7.52(m,3H),7.32-7.36(m,5H),7.20-7.24(m,3H),7.02-7.14(m,8H),6.56-6.65(m,4H),6.49(s, 1H). As shown in fig. 2. Calculated value C of MALDI-TOF-MS m/s₅₃H₃₂: 668.3, found value [ M⁺]:668.5。

Example 3: synthesis of Compound 35

Synthesis of intermediate 3-1

7.7g of intermediate 3-0, 0.15g of cuprous iodide and 0.3g of tetratriphenylphosphine palladium were added to the flask, and then triethylamine was added thereto, nitrogen gas was introduced, stirring was started to sufficiently dissolve the intermediate, and then 10ml of trimethylsilylacetylene was added thereto, and the mixture was refluxed overnight for 12 hours. The solvent was removed under reduced pressure. Water was added, extraction was carried out three times with ether, the organic phases were combined, washed three times with saturated brine, dried, filtered with suction, and concentrated to give 6.8g of product in 67% yield.

Synthesis of intermediate 3-2

To the flask were added 45ml of methanol, 50ml of dichloromethane, 5g of potassium hydroxide, 5.5g of intermediate 3-1, and the reaction was stirred for 1 hour with nitrogen. The inorganic salts were removed by filtration, the organic solvent was removed, and the cake was recrystallized from methanol to give 4.11g, yield 95%.

Synthesis of Compound 35

4.0g of intermediate 3-2 and 5.5g of intermediate 1-3, 60ml of diphenyl ether were put into a four-necked flask, and stirred, nitrogen was introduced for 10 minutes, and heating reflux was started for 12 hours, followed by cooling, filtration, heating reflux of the cake with ethyl acetate, cooling, and filtration to obtain 4.5g of a pale yellow solid with a yield of 49%.¹H NMR(400MHz,CD₂Cl₂,): 8.12-8.13 (d, J =7.6Hz,2H),7.74-7.77(m,4H),7.52-7.60(m,3H),7.25-7.45(m,19H),6.69-6.81(d, J =7.2Hz,1H)₄₆H₂₉N: 595.2, found value [ M⁺]:595.4。

Example 4: synthesis of Compound 26

The synthesis process is the same as that of example 1

Example 5: synthesis of Compound 36

Synthesis of intermediate 5-1

9.1g of the compound 5-0, 0.15g of cuprous iodide, 0.24g of tetratriphenylphosphine palladium, 100ml of triethylamine, nitrogen gas and the like were added to the flask, stirring was started to sufficiently dissolve the compound, 10ml of trimethylsilylacetylene was added, and the mixture was refluxed overnight for 12 hours. The solvent was removed under reduced pressure. Water was added, extraction was carried out three times with ether, the organic phases were combined, washed three times with saturated brine, dried, filtered with suction, and concentrated to give 6.8g of product in 74% yield.

Synthesis of intermediate 5-2

To the flask were added 45ml of methanol, 50ml of dichloromethane, 5g of potassium hydroxide, 7g of intermediate 2-1, and the reaction was stirred for 1 hour with introduction of nitrogen. The inorganic salts were removed by filtration, the organic solvent was removed, and the filter cake was recrystallized from methanol to give 5.0g, 83% yield.

Synthesis of Compound 36

4.8g of intermediate 6-2 and 3.9g of intermediate 1-3, 60ml of diphenyl ether were added to a four-necked flask, and stirring was started, nitrogen was introduced for 10 minutes, and heating reflux was started for 12 hours, followed by cooling, filtration, heating reflux of the cake with ethyl acetate, cooling, and filtration to obtain 5.5g of a pale yellow solid with a yield of 65%.¹H NMR(400MHz,CD₂Cl₂,): 8.14-8.16 (d, J =8.4Hz,4H),7.72-7.80(m,4H),7.54-7.69(m,11H),7.27-7.50(m,16H),6.74-6.76(d, J =6.8Hz,1H) as in fig. 3. Calculated value C of MALDI-TOF-MS m/s₅₉H₃₆N₂: 760.3, found [ M⁺]:760.5。

Example 6

The glass transition temperature of compound 26 was tested by DSC method at a heating and cooling rate of 20 ℃/min under nitrogen. The glass transition temperature Tg of compound 26 was measured to be 140 ℃. The glass transition temperatures of compound 35, compound 36, compound 43, and compound 46 were measured in the same manner, and the results are shown in Table 1.

Comparative example 1

Under the same conditions as in example 1, the glass transition temperatures of the compounds mCP and BCP were measured, and the results are also shown in Table 1.

From table 1, it can be seen that the compounds of the present invention have higher glass transition temperatures than conventional marketed host materials, and the present invention improves the thermal stability of electroluminescent materials.

EXAMPLE 7

The OLED is prepared by using the organic electroluminescent material of the invention, and the device structure is shown in figure 1

First, a transparent conductive ITO glass (glass substrate 10 with anode 20) is sequentially passed through: washing with detergent solution, deionized water, ethanol, acetone and deionized water. CF further treated with oxygen plasma for 30 seconds, followed by plasma treatment_xAnd (6) processing.

Then, MoO was evaporated onto ITO to a thickness of 5nm₃A hole injection layer 30.

Then, TAPC was evaporated to form a hole transport layer 40 having a thickness of 50 nm.

Then, a light-emitting layer 50 having a thickness of 10nm was deposited on the hole-transporting layer, wherein the compound 35 was used as a host light-emitting material and 10% FIrpic was used as a blue phosphorescent material.

Then, TmPyPb was deposited on the light-emitting layer to a thickness of 50nm as an electron transporting layer 60.

Finally, 1.2nm LiF is evaporated as the electron injection layer 70 and the 150nm Al cathode.

The current density of the organic electroluminescent device prepared by the invention is 0.28mA/cm under the driving voltage of 4V²Hair waving deviceEmitting blue light.

Comparative example 2

The device structure was the same as example 7 except that CBP was used instead of compound 35.

The current density of the organic electroluminescent device prepared in this comparative example was 0.17mA/cm at a driving voltage of 4V²And emits blue light.

Therefore, the present invention has improved electroluminescent properties with a higher current density at the same driving voltage than conventional materials.

Claims (11)

1. An organic electronic material having a structure represented by the following formula (I) or (II),

wherein the content of the first and second substances,

R₁-R₅any four of which are hydrogen and the other is carbazolyl; or

R₁、R₃、R₅Is hydrogen, R₂、R₄Are respectively independentIs a carbazolyl group;

a is independently represented by C (R)₆)₂、N(R₇)、S、O、P(R₈)、S(O)₂Or B (R)₉)，R₆-R₉Independently represent hydrogen, deuterium, alkyl, phenyl, alkylphenyl, or two R₆And C form a ring structure.

2. The organic electronic material of claim 1, wherein R₁、R₂、R₄、R₅Is hydrogen.

3. The organic electronic material of claim 1, wherein A is C (R)₆)₂、N(R₇)、S、O、S(O)₂，R₆、R₇Independently hydrogen, methyl, phenyl or methylphenyl, or two R₆And C form a five-membered ring structure.

4. The organic electronic material of claim 1, having the structure:

5. the organic electronic material of claim 1, having the formula:

6. an organic electroluminescent device comprising the organic electronic material as claimed in any one of claims 1 to 5.

7. The organic electroluminescent device according to claim 6, comprising a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer or/and an electron injection layer, wherein the organic electronic material according to any one of claims 1 to 5 is used as a material in any one or more of the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer or/and the electron injection layer.

8. The organic electroluminescent device according to claim 7, wherein the organic electronic material according to any one of claims 1 to 5 is used as a material for an electron transport layer.

9. The organic electroluminescent device according to claim 7, wherein the light-emitting layer comprises a host material and a guest material, and the organic electronic material according to any one of claims 1 to 5 is a host material for blue phosphorescence in the light-emitting layer.

10. The organic electroluminescent device according to claim 9, wherein the guest material is an organic iridium compound or an organic platinum compound.

11. An organic electroluminescent device according to claim 9 or 10, the organic electronic material according to any one of claims 1 to 5 being a material of an electron transport layer.