CN106898709A - A kind of red phosphorescent organic electroluminescence device - Google Patents

Abstract

The invention discloses a red phosphorescent organic electroluminescence device, which comprises a light-emitting layer, and is characterized in that the material of the light-emitting layer includes a host material and a red phosphorescent dye doped in the host material, and the host material has the formula I, one of the compounds of formula II or formula III, Formula I, , Formula II, Formula III, wherein, in formula I and formula II, D is an electron-donating group; in formula III, one of R _1-5 is a cyano group, two are hydrogen groups, and the other two are the same or different electron-donating groups. electronic group. In the red phosphorescent organic electroluminescent device of the present invention, the TADF material of DAD-type fluorenone group, dibenzothiophene sulfone group or phthalonitrile group is used as the host material of red phosphorescence for the light-emitting layer. Such devices can improve the efficiency and life of the device, and reduce the driving voltage of the device.

Description

A red phosphorescent organic electroluminescent device

technical field

The invention belongs to the field of organic electroluminescent devices, in particular to a red phosphorescent organic electroluminescent device whose luminescent layer adopts a novel host material.

Background technique

Organic electroluminescent devices have attracted widespread attention due to their thin body, large area, full curing, and flexibility, and their great potential in solid-state lighting sources and liquid crystal backlights has become a research hotspot.

As early as the 1950s, Bernanose.A et al. started research on organic electroluminescent devices (OLEDs). The material initially studied was an anthracene single wafer. Due to the problem of the large thickness of a single wafer, the required driving voltage is very high. Until 1987, Deng Qingyun (CWTang) and Vanslyke of Eastman Kodak Company in the United States reported an organic small molecule electroluminescent device with a structure of: ITO/Diamine/Alq ₃ /Mg:Ag, and the brightness of the device reached 1000cd at a working voltage of 10 volts. /m ² , the external quantum efficiency reaches 1.0%. The study of electroluminescence has attracted widespread attention of scientists, and people have seen the possibility of organic electroluminescent devices being used in displays, which has opened the prelude to the research and industrialization of organic electroluminescent devices. The organic light-emitting material system includes a fluorescent system and a phosphorescent system, in which the fluorescent system only utilizes the energy of the singlet excitons, while the phosphorescent system can simultaneously utilize the energy of the triplet excitons.

The triplet energy gap of the phosphorescent host material must be higher than that of the phosphorescent dopant material in order to confine the triplet excitons of the phosphorescent material in the light-emitting layer, because if the triplet excited state energy of the phosphorescent material is higher than that of the host material When it is high, the energy is easily transferred back from the triplet excited state of the phosphorescent dopant material to the triplet state of the host material, thereby reducing the luminous efficiency of the device.

The well-known 4,4'-bis(N-carbazole)biphenyl (CBP) is a host material with high efficiency and large excited triplet energy, but the life of the device using CBP as the host is very short. It is speculated that it may be CBP Due to structural problems, CBP is degraded due to low oxidation stability, so it cannot be practically used in OLED devices.

Contents of the invention

The technical problem to be solved by the present invention is that the red phosphorescent organic electroluminescent device has fewer types of host materials in the prior art, and the existing host materials have low oxidation stability.

In order to solve the above technical problems, the present invention provides a red phosphorescent organic electroluminescent device, the light-emitting layer adopts a new TADF material as the host material, which has the ability to transport holes and electrons at the same time, by adjusting different substituent groups Higher thermochemical stability can be obtained. In addition, the ΔE _ST between the HOMO and LUMO of these materials is very small (<0.3eV), and a higher anti-intersystem crossing coefficient (k _RISC ) can be obtained, thereby shortening the lifetime of triplet excitons and improving improve the efficiency and stability of OLED devices. At the same time, the high energy gap of the host material of the present invention confines the excitons in the light-emitting region, so that the recombination region of the excitons is in the entire light-emitting layer, which can effectively improve the efficiency of the device. These properties allow these materials to be used as host materials in high-efficiency OLED red phosphorescent devices, and long-lived, high-efficiency OLED devices can be obtained.

The red phosphorescent organic electroluminescent device of the present invention includes a light emitting layer, the material of the light emitting layer includes a host material and a red phosphorescent dye doped in the host material,

The host material is one of the compounds having the structure of formula I, formula II or formula III,

Among them, in formula I and formula II, D is an electron-donating group; in formula III, one of R ₁ -R ₅ is a cyano group, two are hydrogen groups, and the other two are the same or different electron-donating groups group.

Preferably, in formula I and formula II, D is selected from the following groups:

In formula III, one of R ₁ -R ₅ is a cyano group, two are hydrogen groups, and the other two are electron-donating groups selected from the following structures:

Preferably, in formula III, at least one of the substituents adjacent to the cyano group is a hydrogen group.

Specifically, the host material is a compound with the following structure:

The compound with formula I structure is following compound:

The compound with formula II structure is the following compound:

Preferably, the proportion of the red phosphorescent dye in the light-emitting layer is 0.5wt%-5wt%, more preferably 1wt%-3wt%.

Wherein, the red phosphorescent dye is one or more of the metal complexes containing Ir, Eu, Os, preferably one or more of the metal complexes containing Ir, more preferably Ir(piq) ₃ , Ir(piq) ₂ (acac), Ir(piq-F) ₂ (acac), Ir(m-piq) ₂ (acac), Ir(DBQ) ₂ (acac), Ir(MDQ) ₂ (acac), One or more of Ir(bt) ₂ (acac) or Ir(bt) ₃ .

The above-mentioned red phosphorescent organic electroluminescent device comprises a stacked anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and a cathode sequentially deposited on a substrate.

In the red phosphorescent organic electroluminescent device of the present invention, the TADF material of D-A-D type fluorenone group, dibenzothiophene sulfone group or phthalonitrile group is used as the host material of red phosphorescence for the light-emitting layer, and the Such devices can improve the efficiency and life of the device, and reduce the driving voltage of the device. The present invention can reach following beneficial effect:

1. The doping concentration of the red phosphorescent dye is low, and the cost is reduced.

2. Energy transfer can reduce triplet-triplet annihilation (TTA), improve exciton utilization, and thus improve device efficiency and lifetime.

3. △E _ST is small (<0.3eV), this type of electron acceptor has good stability, and the torsion angle between the acceptor and the donor is small, and the radiation transition rate is high.

4. △E _ST is small (<0.3eV), and the singlet S ₁ of _TADF materials is lower than that of common hosts, which is expected to reduce the device driving voltage.

Description of drawings

Fig. 1 is the structural representation of red phosphorescent organic electroluminescence device of the present invention;

2 is a schematic diagram of the energy transfer process in the light-emitting layer of the phosphorescent organic electroluminescent device in the prior art;

Fig. 3 is a schematic diagram of the energy transfer process in the light-emitting layer of the red phosphorescent organic electroluminescent device of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it, but the examples given are not intended to limit the present invention.

As shown in FIG. 1 , the red phosphorescent organic electroluminescent device of the present invention includes an anode 02, a hole injection layer 04, a hole transport layer 05, a light emitting layer 06, an electron transport layer 07 and Cathode 03.

The material of the light-emitting layer 06 includes a host material and a red phosphorescent dye doped in the host material,

The host material is one of the compounds having the structure of formula I, formula II or formula III,

Among them, in formula I and formula II, D is an electron-donating group; in formula III, one of R _1-5 is a cyano group, two are the same or different electron-donating groups, and the other two are hydrogen groups .

Among them, in formula I and formula II, D is preferably phenoxazinyl [formula (11)], phenothiazinyl [formula (12)], 9,9-dimethylacridinyl [formula (13)] , 9-methylphenazinyl [formula (14)], 9-phenylphenazinyl [formula (15)], 4-phenoxazinyl-1-phenyl [formula (16)], 4-phen Thiazinyl-1-phenyl[formula (17)], 4-(9,9-dimethyl)acridinyl-1-phenyl[formula (18)], 4-(9-methyl)phen Azinyl-1-phenyl [formula (19)], 4-(9-phenyl)phenazinyl-1-phenyl [formula (20)], 3,5-dicarbazolyl-1-phenyl [Formula (21)], as follows:

The electron-donating group in formula III is selected from the following groups:

Above-mentioned host material of the present invention is TADF material:

In the TADF host-sensitized phosphorescent device, the doping concentration of the phosphorescent dye is lower than that of the phosphorescent device where the common host is located, because the excitons first pass through the triplet state of the TADF host to the singlet state of the TADF host. , and then by the long-range Energy is transferred to the triplet state of the phosphorescent host. Most importantly, TADF-sensitized phosphorescence enables long-lived and high-efficiency devices at low doping concentrations.

Specifically, referring to FIG. 1 , FIG. 2 and FIG. 3 , the energy transfer process in the light-emitting layer 06 of the present invention will be described.

As shown in Figure 2, the light-emitting layer in the prior art is a conventional phosphorescent host material doped with a phosphorescent dye, and the difference between the triplet energy level and the singlet energy level of the conventional phosphorescent host material is relatively large, and the energy transfer process is as follows: excitons from the host material The triplet energy level is transferred to the triplet energy level of the phosphorescent dye through the short-range Dexter energy. At the same time, the excitons can also be transferred from the singlet energy level of the host material to Energy is transferred to the singlet energy level of the phosphorescent dye. The short-range Dexter energy transfer leads to a higher doping concentration of phosphorescent dyes, which can reduce the distance between the host and phosphorescent dyes and promote the complete transfer of energy, but higher phosphorescent dyes will cause device attenuation, and the cost of phosphorescent dyes containing noble metals higher.

The thermally activated delayed fluorescent material (TADF material) as the host material has a small difference between the energy level of the triplet state and the energy level of the singlet state (ΔE _ST <0.3eV, preferably ΔE _ST <0.15eV). As shown in Figure 3, in the light-emitting layer in which the TADF material is the host and doped with phosphorescent dyes, during the energy transfer process from the host material to the dye, the excitons jump from the triplet energy level of the TADF host material to its opposite system. singlet level, and then from the host singlet level via the long-range Energy transfer to the triplet level of the phosphorescent dye.

In the red phosphorescent organic electroluminescent device, the coordination group of the red phosphorescent dye has a small HOMO-LUMO electron cloud density, so its host material is best to choose a wide energy gap (>3.0eV), lower triplet excitation The material of the state energy level, (the difference between the triplet energy level of the TADF host material and the triplet energy level of the phosphorescent material is <0.3eV), so the formulas Ⅰ～Ⅲ are used as the host material of red phosphorescence.

The material with the structure of formula I is as follows:

The material with the structure of formula II is as follows:

The following examples of the compound (phthalonitrile compound) having the structure of formula III only exemplify several preferred structures:

The preparation method of each compound is as follows:

Synthesis Example 1

Synthesis of compounds of structure shown in formula (1-1): under nitrogen range, 3,6-dibromo-9-fluorenone (5mmol), phenoxazine (18mmol), Pd ₂ (dba) ₃ (0.8mmol) , NaOtBu (30 mmol) and tBu ₃ P·HBF ₄ (0.8 mmol) were put into 100 mL of toluene and stirred at 105° C. overnight. The reaction was quenched by adding 10 mL of cold water to the mixture. After the mixture was cooled to room temperature, it was vacuum filtered, followed by purification by column chromatography to obtain the product with the structure shown in formula (1-1), and the product was dried in vacuum. Yield: 80%.

The molecular weight obtained by mass spectrometry: 542.58.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 81.90%; H: 4.09%; N: 5.16%; O: 8.85%.

Synthesis Example 2

Synthetic compound of structure shown in formula (1-2): reactant phenoxazine is replaced by phenothiazine, through the same synthetic method as Synthetic Example 1, the compound of structure shown in formula (1-2) is obtained, productive rate 91% .

The molecular weight obtained by mass spectrometry: 574.71.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 77.32%; H: 3.86%; N: 4.87%; O: 2.78%; S, 11.16%.

Synthesis Example 3

Synthetic compound of structure shown in formula (1-3): the reactant phenoxazine is replaced by 9,9-dimethylacridine, through the same synthetic method as in Synthesis Example 1, the structure shown in formula (1-3) is obtained Compound, yield 87%.

The molecular weight obtained by mass spectrometry: 594.74.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 86.84%; H: 5.76%; N: 4.71%; O: 2.69%.

Synthesis Example 4

Synthetic compound of structure shown in formula (1-4): reactant phenoxazine is replaced by 9-methylphenazine, through the synthetic method identical with synthetic example 1, obtains the compound of structure shown in formula (1-4), produces The rate is 79%.

The molecular weight obtained by mass spectrometry: 568.67.

Elemental analysis: C: 82.37%; H: 4.96%; N: 9.85%; O: 2.81%.

Synthesis Example 5

Synthetic compound of structure shown in formula (1-5): reactant phenoxazine is replaced by 9-phenylphenazine, through the synthetic method identical with synthetic example 1, obtains the compound of structure shown in formula (1-5), produces rate of 82%.

The molecular weight obtained by mass spectrometry: 692.80.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 84.95%; H: 4.66%; N: 8.09%; O: 2.31%.

Synthesis Example 6

Synthesis of structural compounds shown in formula (1-6): under nitrogen range, 3,6-dibromo-9-fluorenone (5mmol), 4-phenoxazinyl-1-phenylboronic acid (18mmol), Pd ₂ (pph ₃ ) ₄ (0.8mmol), K ₃ PO ₄ (0.8mmol) were put into 100mL 1,,4dioxane and stirred overnight at 70°C. After the mixture was cooled to room temperature, the product formula (1-6) was purified by vacuum filtration, followed by column chromatography, and the product was dried in vacuum. Yield: 86%.

The molecular weight obtained by mass spectrometry: 694.77.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 84.71%; H: 4.35%; N: 4.03%; O: 6.91%.

Synthesis Example 7

Synthetic compound of structure shown in formula (1-7): reactant 4-phenoxazinyl-1-phenylboronic acid is replaced by 4-phenothiazinyl-1-phenyl, through the same synthetic method as Synthetic Example 6 , to obtain the structural compound represented by formula (1-7), with a yield of 84%.

The molecular weight obtained by mass spectrometry: 726.91.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 80.96%; H: 4.16%; N: 3.85%; O: 2.20%; S: 8.82%.

Synthesis Example 8

Compound of structure shown in synthetic formula (1-8): reactant 4-phenoxazinyl-1-phenylboronic acid is replaced with 4-(9,9-dimethyl) acridinyl-1-phenylboronic acid, after The same synthesis method as in Synthesis Example 6 was used to obtain the compound of formula (1-8) with a yield of 81%.

The molecular weight obtained by mass spectrometry: 746.93.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 88.44%; H: 5.67%; N: 3.75%; O: 2.14%.

Synthesis Example 9

Structural compound shown in synthetic formula (1-9): reactant 4-phenoxazinyl-1-phenylboronic acid is replaced by 4-(9-methyl) phenazinyl-1-phenylboronic acid, through and synthetic implementation The same synthesis method as in Example 6 was used to obtain the compound of formula (1-9) with a yield of 75%.

The molecular weight obtained by mass spectrometry: 720.86.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 84.97%; H: 5.03%; N: 7.77%; O: 2.22%.

Synthesis Example 10

Compound of structure shown in synthetic formula (1-10): reactant 4-phenoxazinyl-1-phenylboronic acid is replaced by 4-(9-phenyl) phenazinyl-1-phenylboronic acid, through and synthetic implementation The same synthesis method as in Example 6 was used to obtain the compound of formula (1-10) with a yield of 79%.

The molecular weight obtained by mass spectrometry: 845.00.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 86.70%; H: 4.77%; N: 6.63%; O: 1.89%.

Synthetic Example 11

Synthetic compound of structure shown in formula (1-11); reactant 4-phenoxazinyl-1-phenylboronic acid is replaced by 3,5-dicarbazolyl-1-phenylboronic acid, through the same process as in Synthesis Example 6 According to the synthetic method, the structural compound shown in formula (1-11) was obtained, and the yield was 88%.

The molecular weight obtained by mass spectrometry: 993.16.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 88.28%; H: 4.47%; N: 5.64%; O: 1.61%.

Synthetic Example 12

Synthesis of compounds with the structure shown in formula (2-1): Add 3,6-dibromo-dibenzothiophene (5mmol) to a mixed solution of 50mL hydrogen peroxide and 50mL glacial acetic acid, and reflux at 110°C for 5h to obtain 3 ,6-Dibromo-dibenzothiophene sulfone. Under nitrogen range, 3,6-dibromo-dibenzothiophene sulfone (5mmol), phenoxazine (18mmol), Pd ₂ (dba) ₃ (0.8mmol), NaOtBu (30mmol) and tBu3P·HBF4 (0.8 mmol) were put into 100 mL of toluene and stirred overnight at 105 °C. The reaction was quenched by adding 10 mL of cold water to the mixture. After the mixture was cooled to room temperature, the product formula (2-1) was purified by vacuum filtration, followed by column chromatography, and the product was dried in vacuum. Yield: 80%.

The molecular weight obtained by mass spectrometry: 578.64.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 74.72%; H: 3.83%; N: 4.84%; O: 11.06%; S: 5.54%.

Synthetic Example 13

Synthetic compound of structure shown in formula (2-2): the reactant phenoxazine is replaced by phenothiazine, through the same synthetic method as Synthetic Example 12, the compound of structure shown in formula (2-2) is obtained, yield 87% .

The molecular weight obtained by mass spectrometry: 610.77.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 70.79%; H: 3.63%; N: 4.59%; O: 5.24%; S: 15.75%.

Synthetic Example 14

Synthetic compound of structure shown in formula (2-3): the reactant phenoxazine is replaced by 9,9-dimethylacridine, through the same synthetic method as in Synthesis Example 12, the structure shown in formula (2-3) is obtained Compound, yield 76%.

The molecular weight obtained by mass spectrometry: 630.80.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 79.97%; H: 5.43%; N: 4.44%; O: 5.07%; S: 5.08%.

Synthetic Example 15

Synthetic compound of structure shown in formula (2-4): reactant phenoxazine is replaced by 9-methyl phenazine, through the synthetic method identical with synthetic example 12, obtains the compound of structure shown in formula (2-4), produces rate of 81%.

The molecular weight obtained by mass spectrometry: 604.72.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 75.47%; H: 4.67%; N: 9.26%; O: 5.29%; S: 5.30%.

Synthetic Example 16

Synthetic compound of structure shown in formula (2-5): reactant phenoxazine is replaced by 9-phenylphenazine, through the synthetic method identical with synthetic example 12, obtains the compound of structure shown in formula (2-5), produces The rate is 78%.

The molecular weight obtained by mass spectrometry: 728.86.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 79.10%; H: 4.43%; N: 7.69%; O: 4.39%; S: 4.40%.

Synthetic Example 17

Synthesis of compounds of the structure shown in formula (2-6): Add 3,6-dibromo-dibenzothiophene (5mmol) to a mixed solution of 50mL hydrogen peroxide and 50mL glacial acetic acid, and reflux at 110°C for 5h to obtain 3 ,6-Dibromo-dibenzothiophene sulfone. Under nitrogen range, 3,6-dibromo-dibenzothiophene (5mmol), 4-phenoxazinyl-1-phenylboronic acid (18mmol), Pd ₂ (pph ₃ ) ₄ (0.8mmol), K ₃ PO ₄ (0.8 mmol) was put into 100 mL of 1,,4-dioxane and stirred overnight at 70°C. After the mixture was cooled to room temperature, the product formula (2-6) was purified by vacuum filtration, followed by column chromatography, and the product was dried in vacuum. Yield: 86%.

The molecular weight obtained by mass spectrometry: 730.83.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 78.89%; H: 4.14%; N: 3.83%; O: 8.76%; S: 4.39%.

Synthetic Example 18

Synthetic compound of structure shown in formula (2-7): reactant 4-phenoxazinyl-1-phenylboronic acid is replaced by 4-phenothiazinyl-1-phenyl, through the same synthetic method as Synthetic Example 17 , to obtain the structural compound shown in formula (2-7), with a yield of 72%.

The molecular weight obtained by mass spectrometry: 762.96.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 75.56%; H: 3.96%; N: 3.67%; O: 4.19%; S: 12.61%.

Synthetic Example 19

Compound of structure shown in synthetic formula (2-8): reactant 4-phenoxazinyl-1-phenylboronic acid is replaced with 4-(9,9-dimethyl) acridinyl-1-phenylboronic acid, after The same synthesis method as in Synthesis Example 17 was used to obtain the compound of formula (2-8) with a yield of 77%.

Molecular mass analysis by mass spectrometry: 782.99.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 82.83%; H: 5.41%; N: 3.58%; O: 4.09%; S: 4.10%.

Synthetic Example 20

Structural compound shown in synthetic formula (2-9): reactant 4-phenoxazinyl-1-phenylboronic acid is replaced by 4-(9-methyl) phenazinyl-1-phenylboronic acid, through and synthetic implementation The same synthetic method as in Example 17, the compound with the structure shown in formula (2-9) was obtained with a yield of 65%.

The molecular weight obtained by mass spectrometry: 756.91.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 79.34%; H: 4.79%; N: 7.40%; O: 4.23%; S: 4.24%.

Synthetic Example 21

Compound of structure shown in synthetic formula (2-10): reactant 4-phenoxazinyl-1-phenylboronic acid is replaced by 4-(9-phenyl) phenazinyl-1-phenylboronic acid, through and synthetic implementation The same synthetic method as in Example 17, the compound with the structure shown in formula (2-10) was obtained with a yield of 85%.

The molecular weight obtained by mass spectrometry: 881.05.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 81.79%; H: 4.58%; N: 6.36%; O: 3.63%; S: 3.64%.

Synthetic Example 22

Synthetic compound of structure shown in formula (2-11): reactant 4-phenoxazinyl-1-phenylboronic acid is replaced by 3,5-dicarbazolyl-1-phenylboronic acid, through the same as Synthetic Example 17 According to the synthetic method, the structural compound shown in formula (2-11) was obtained, and the yield was 75%.

The molecular weight obtained by mass spectrometry: 1029.21.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 84.02%; H: 4.31%; N: 5.44%; O: 3.11%; S: 3.12%.

Synthetic Example 23

Synthesis of compounds of structure shown in formula (3-1): under nitrogen range, 4,5-difluoro-1,2-dicyanobenzene (5mmol), phenoxazine (18mmol), Pd ₂ (dba) ₃ (0.8mmol), NaOtBu (30mmol) and tBu3P·HBF4 (0.8mmol) were put into 100mL DMF and stirred at 80°C overnight. The reaction was quenched by adding 10 mL of cold water to the mixture. After the mixture was cooled to room temperature, the product formula (3-1) was purified by vacuum filtration, followed by column chromatography, and the product was dried in vacuum. Yield: 69%.

Molecular mass analysis by mass spectrometry: 490.14.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 78.36%; H: 3.70%; N: 11.42%; O: 6.52%.

Synthetic Example 24

Synthetic compound of structure shown in formula (3-2): the reactant phenoxazine is replaced by phenothiazine, through the same synthetic method as Synthetic Example 23, the compound of structure shown in formula (3-2) is obtained, yield 79% .

Molecular mass analysis by mass spectrometry: 522.10.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 73.54%; H: 3.47%; N: 10.72%; S: 12.27%.

Synthetic Example 23

Synthetic compound of structure shown in formula (3-3): the reactant phenoxazine is replaced by 9,9-dimethylacridine, through the same synthesis method as in Synthesis Example 23, the structure shown in formula (3-3) is obtained Compound, yield 82%.

The molecular weight obtained by mass spectrometry: 542.25.

Elemental analysis: C: 84.10%; H: 5.57%; N: 10.32%.

Synthetic Example 24

Synthesis of structural compounds shown in formula (3-4): under nitrogen range, 4,5-dibromo-1,2-dicyanobenzene (5mmol) (5mmol), 4-(9,9-dimethyl )acridinyl-1-phenylboronic acid (18mmol), Pd ₂ (pph ₃ ) ₄ (0.8mmol), K ₃ PO ₄ (0.8mmol) were put into 100mL 1,4 dioxane and heated at 70°C Stir overnight. After the mixture was cooled to room temperature, the product formula (3-4) was purified by vacuum filtration, followed by column chromatography, and the product was dried in vacuum. Yield: 65%.

The molecular weight obtained by mass spectrometry: 694.31.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 86.42%; H: 5.51%; N: 8.06%.

Synthetic Example 25

Compound of structure shown in synthetic formula (3-5): reactant 4-(9,9-dimethyl) acridinyl-1-phenylboronic acid is replaced by 4-phenoxazinyl-1-phenylboronic acid, after The same synthesis method as in Synthesis Example 24 was used to obtain the compound of formula (3-5) with a yield of 62%.

The molecular weight obtained by mass spectrometry: 642.21.

Elemental analysis: C: 82.23%; H: 4.08%; N: 8.72%; O: 4.98%.

Synthetic Example 26

Compound of structure shown in synthetic formula (3-6): reactant 4-(9,9-dimethyl) acridinyl-1-phenylboronic acid is replaced by 4-phenothiazinyl-1-phenyl, through and The same synthesis method as in Example 24 was used to obtain the compound of formula (3-6) with a yield of 70%.

The molecular weight obtained by mass spectrometry: 674.16.

The relative molecular mass percentages of each element obtained by elemental analysis: C: 78.31%; H: 3.88%; N: 8.30%; S: 9.50%.

Synthetic Example 27

Synthetic method of the structural compound shown in formula (3-7): under nitrogen range, 4,6-difluoro-1,3-dicyanobenzene (5mmol), 4-(9-methyl)phenazinyl- 1-Phenyl (18 mmol), Pd ₂ (dba) ₃ (0.8 mmol), NaOtBu (30 mmol) and tBu3P·HBF4 (0.8 mmol) were put into 100 mL of DMF and stirred at 80° C. overnight. The reaction was quenched by adding 10 mL of cold water to the mixture. After the mixture was cooled to room temperature, the product formula (3-7) was purified by vacuum filtration, followed by column chromatography, and the product was dried in vacuum. Yield: 45%.

The molecular weight obtained by mass spectrometry: 668.27.

The relative molecular mass percentages of each element obtained by elemental analysis: C, 82.61%; H, 4.82%; N, 12.57%.

Synthetic Example 28

Synthesis method of the structural compound shown in formula (3-8): the reactant 4-(9-methyl)phenazinyl-1-phenyl is replaced by 9-phenylphenazinyl, and the same synthesis as in Synthesis Example 27 method to obtain the structural compound represented by formula (3-8) with a yield of 39%.

The molecular weight obtained by mass spectrometry: 640.24.

The relative molecular mass percentages of each element obtained by elemental analysis: C, 82.48%; H, 4.40%; N, 13.12%.

Synthetic Example 29

Synthetic method of structural compounds shown in formula (3-9): under nitrogen range, 2,5-difluoro-1,4-dicyanobenzene (5mmol), 4-phenoxazinyl-1-phenyl ( 18 mmol), Pd ₂ (dba) ₃ (0.8 mmol), NaOtBu (30 mmol) and tBu3P·HBF4 (0.8 mmol) were put into 100 mL DMF and stirred overnight at 80°C. The reaction was quenched by adding 10 mL of cold water to the mixture. After the mixture was cooled to room temperature, the product formula (3-9) was purified by vacuum filtration, followed by column chromatography, and the product was dried in vacuum. Yield: 46%.

The molecular weight obtained by mass spectrometry: 642.21.

The relative molecular mass percentages of each element obtained by elemental analysis: C, 82.23%; H, 4.08%; N, 8.72%, O, 4.98%.

Synthetic Example 30

Synthetic method of structural compound shown in formula (3-10): reactant 4-phenoxazinyl-1-phenyl is replaced by 4-(9,9-dimethyl) acridinyl-1-phenyl, through and The same synthesis method as in Synthesis Example 28 was used to obtain the compound of formula (3-10) with a yield of 41%.

The molecular weight obtained by mass spectrometry: 694.31.

The relative molecular mass percentages of each element obtained by elemental analysis: C, 86.42%; H, 5.51%; N, 8.06%.

As shown in Figure 1, in the embodiment of the organic electroluminescent device of the present invention:

The anode 02 can be made of inorganic materials or organic conductive polymers. Inorganic materials are generally metal oxides such as indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), or metals with higher work functions such as gold, copper, and silver, preferably ITO; organic conductive polymers are preferably One of polythiophene/sodium polyvinylbenzenesulfonate (hereinafter referred to as PEDOT/PSS) and polyaniline (hereinafter referred to as PANI).

Cathode 03 generally uses metals with low work functions such as lithium, magnesium, calcium, strontium, aluminum, indium, or their alloys with copper, gold, and silver, or an electrode layer formed alternately of metals and metal fluorides. In the present invention, the cathode 03 is preferably a laminated LiF layer and Al layer (the LiF layer is on the outside).

The material of the hole transport layer 05 can be selected from aromatic amines and dendrimer low molecular materials, preferably NPB.

The material of the electron transport layer 07 can be an organometallic complex (such as Alq ₃ , Gaq ₃ , BAlq or Ga(Saph-q)) or other materials commonly used in the electron transport layer 07, such as aromatic condensed rings (such as pentacene, perylene ) or o-phenanthroline (such as Bphen, BCP) compounds.

The organic electroluminescent device of the present invention can also have a hole injection layer 04 between the anode 02 and the hole transport layer 05, and the material of the hole injection layer 04 can be, for example, 4,4',4"-tri( 3-methylphenylaniline) triphenylamine doped F4TCNQ, or copper phthalocyanine (CuPc), or metal oxides, such as molybdenum oxide, rhenium oxide.

The thickness of each of the above-mentioned layers can adopt the conventional thickness of these layers in the art.

The present invention also provides a method for preparing the organic electroluminescence device, which includes sequentially depositing an anode 02, a hole injection layer 04, a hole transport layer 05, a light emitting layer 06, an electron transport layer 07 and a cathode stacked on a substrate 01. 03, then package.

The substrate 01 can be glass or a flexible substrate, and the flexible substrate can be made of polyester, polyimide compound material or thin metal sheet. The lamination and packaging can adopt any suitable method known to those skilled in the art.

The structural formula of the red phosphorescent dye doped in the light-emitting layer 06 in the following examples of the present invention is as follows:

Comparative example 1:

In this comparative example, ITO (indium tin oxide) is used as the anode; NPB is used as the hole injection layer; _TCTA is used as the hole transport layer; The mass percentage of doping in is 3wt%); Bphen is used as the electron transport layer; Li(5nm)/Al is used as the cathode. The structure is as follows:

ITO/NPB(40nm)/TCTA(10nm)/CBP:3wt%Ir(piq) ₂ (acac)(30nm)/Bphen(40nm)/LiF(5nm)/Al

Comparative example 2:

The structure of this comparative example is the same as that of comparative example 1 except that the host material used in the light-emitting layer is 4CzIPN (a TADF material in the prior art). The structure is as follows:

ITO/NPB(40nm)/TCTA(10nm)/4CzIPN:3wt%Ir(piq) ₂ (acac)(30nm)/Bphen(40nm)/LiF(5nm)/Al

The above formula is the molecular structural formula of 4CzIPN.

Device Example 1

The structure of this device embodiment is the same as that of Comparative Example 1 except that the host material used in the light-emitting layer 06 is the compound of formula (2-6) of the present invention. The structure is as follows:

ITO/NPB(40nm)/TCTA(10nm)/Formula (2-6):3wt%Ir(piq) ₂ (acac)(30nm)/Bphen(40nm)/LiF(5nm)/Al

Device Example 2

The structure of this device embodiment is the same as that of the device embodiment 1 except that the red phosphorescent dye used in the light emitting layer 06 is Ir(piq) ₃ . The structure is as follows:

ITO/NPB(40nm)/TCTA(10nm)/Formula (2-6):3wt%Ir(piq) ₃ (30nm)/Bphen(40nm)/LiF(5nm)/Al

It can be seen from the above table:

The red phosphorescent organic electroluminescent device of the present invention uses a new heat-activated sensitized fluorescent material as the main body sensitized phosphorescent material device, and the current of the heat-activated sensitized fluorescent material sensitized phosphorescent material device is higher than that of the common main body sensitized phosphorescent material and the reported thermally activated sensitized fluorescent material sensitized phosphorescent material device. The efficiency is high, and the voltage is the lowest, indicating that the ΔE _ST of the heat-activated sensitized fluorescent material used in the host material of the present invention is very small (<0.3eV), and has a relatively high reverse intersystem crossing coefficient (k _RISC ), thereby enabling The lifetime of the triplet excitons becomes shorter, and Energy transfer can reduce triplet-triplet annihilation (TTA), improve exciton utilization, and thus improve device efficiency and lifetime.

Device Embodiment 3 to Device Embodiment 6

The structure of the device embodiment 3 to the device embodiment 6 is the same as that of the device embodiment 1, the only difference lies in the doping concentration of the red phosphorescent dye.

ITO/NPB(40nm)/TCTA(10nm)/Formula (2-6):0.5～5wt%Ir(piq) ₂ (acac)(30nm)/Bphen(40nm)/LiF(5nm)/Al

From the above table it can be seen that:

Under the brightness of 5000cd/m ² , as the doping concentration of the red phosphorescent dye increases, the current efficiency of the red phosphorescent organic electroluminescent device of the present invention rises first and then decreases, reaching the maximum value at a concentration of 1 wt%, and the doping concentration is too high can cause concentration quenching of the device due to the long-range The energy transfer reduces the triplet-triplet annihilation (TTA) and improves the exciton utilization, which in turn increases the device efficiency.

Device Embodiment 7

The structure is the same as the device embodiment 1, the doping concentration of the red phosphorescent dye is 1wt%, and the light emitting layer 06 is made of different TADF materials. The structure is as follows:

One of the compounds of ITO/NPB(40nm)/TCTA(10nm)/Formula I to Formula III: 1wt% Ir(piq) ₂ (acac)(30nm)/Bphen(40nm)/LiF(5nm)/Al

From the above table it can be seen that:

The red phosphorescent organic electroluminescent device of the present invention adopts a new heat-activated sensitized fluorescent material as the main body, which has a lower △EST (< _0.3eV ), and the torsion between the acceptor and the donor in the main material The angle is small, the radiative transition rate is high, and at the same time The energy transfer reduces the triplet-triplet annihilation and improves the exciton utilization, which in turn increases the device efficiency.

The above-mentioned embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention shall be determined by the claims.

Claims (10)

1. a kind of red phosphorescent organic electroluminescence device, including luminescent layer, it is characterised in that the material of the luminescent layer includes Material of main part and the red phosphorescent dye being entrained in material of main part,

The material of main part is the one kind in the compound with formula I, formula II or the structure of formula III,

Formula I,

,

Formula II,

Formula III,

Wherein, in formula I and formula II, D is electron donating group；In formula III, R₁-R₅In have one for cyano group, have two for hydrogen-based, separately Outer two is identical or different electron donating group.

2. red phosphorescent organic electroluminescence device according to claim 1, it is characterised in that

In formula I and formula II, D is selected from following group：

,,,,

,,,,,

；

In formula III, R₁-R₅In have one for cyano group, have two for hydrogen-based, two other each is selected from the electron of following structure Group：

,,,,,,,,,。

3. red phosphorescent organic electroluminescence device according to claim 2, it is characterised in that in formula III, it is and described At least one is hydrogen-based in the substitution base of cyano group adjacent position.

4. red phosphorescent organic electroluminescence device according to claim 1, it is characterised in that the change with structure shown in formula I Compound is following compound：

Formula（1-1）

Formula（1-2）

Formula（1-3）

Formula（1-4）

Formula（1-5）

Formula（1-6）

Formula（1-7）

Formula（1-8）

Formula（1-9）

Formula（1-10）

Formula（1-11）；

Compound with the structure of formula II is following compound：

Formula（2-1）

Formula（2-2）

Formula（2-3）

Formula（2-4）

Formula（2-5）

Formula（2-6）

Formula（2-7）

Formula（2-8）

Formula（2-9）

Formula（2-10）

Formula（2-11）.

5. red phosphorescent organic electroluminescence device according to claim 1, it is characterised in that the red phosphorescent dye Proportion is 0.5wt% ~ 5wt% in luminescent layer.

6. red phosphorescent organic electroluminescence device according to claim 1, it is characterised in that the red phosphorescent dye Proportion is 1wt% ~ 3wt% in luminescent layer.

7. red phosphorescent organic electroluminescence device according to claim 1, it is characterised in that the red phosphorescent dye It is containing Ir, one or more in the metal complex of Eu, Os.

8. red phosphorescent organic electroluminescence device according to claim 7, it is characterised in that the red phosphorescent dye It is one or more in the metal complex containing Ir.

9. red phosphorescent organic electroluminescence device according to claim 8, it is characterised in that the red phosphorescent dye It is Ir (piq)₃, Ir (piq)₂(acac), Ir (piq-F)₂(acac), Ir (m-piq)₂(acac), Ir (DBQ)₂(acac), Ir (MDQ)₂(acac), Ir (bt)₂Or Ir (bt) (acac)₃In one or more.

10. red phosphorescent organic electroluminescence device according to claim 1, it is characterised in that be included on substrate according to It is secondary to deposit anode, hole injection layer, hole transmission layer, luminescent layer, electron transfer layer and the negative electrode being stacked on one another.