CN102911145A - Dibenzo-heterocyclic spirobifluorene compound, preparation method thereof and organic electrophosphorescent device - Google Patents

Abstract

The present invention provides a dibenzoheterocyclic spirobifluorene compound, which has a structure shown in formula I: wherein, X is O or S; Ar is a substituent shown in formula II or formula III. The compound is used as a host material of an organic electrophosphorescent device with good stability, high luminous intensity and high current efficiency. The present invention also provides a preparation method of the compound represented by formula I and an organic electrophosphorescent device comprising the compound represented by formula I.

Description

A dibenzoheterocyclic spirobifluorene compound, its preparation method, and an organic electrophosphorescent device

technical field

The invention relates to the field of organic phosphorescent dyes, in particular to a dibenzoheterocyclic spirobifluorene compound, a preparation method thereof and an organic electrophosphorescent device. the

Background technique

Since 1987, when CW Tang et al. of Kodak reported for the first time that a double-layer device structure with Alq ₃ as a light-emitting material was prepared by vacuum evaporation, organic electroluminescence has attracted great attention.

Organic electroluminescence can be divided into fluorescence and phosphorescence electroluminescence. According to the spin quantum statistics theory, the formation probability ratio of singlet excitons and triplet excitons is 1:3, that is, singlet excitons only account for 25% of the "electron-hole pairs". Therefore, the fluorescence from the radiative transition of singlet excitons only accounts for 25% of the total input energy, while the electroluminescence of phosphorescent materials can use the energy of all excitons, so it has greater advantages. the

Most of the current phosphorescent electroluminescent devices adopt the host-guest structure, that is, the phosphorescent emitting substance is doped in the host material at a certain concentration, so as to avoid concentration quenching and triplet-triplet annihilation, and improve the phosphorescent emission efficiency. the

In 1999, Forrest and Thompson et al [MA Baldo, S.Lamansky, PE Burroes, METhompson, SSR Forrest.Appl.Phys.Lett., 1999,75,4] doped the green phosphorescent material Ir(ppy) ₃ with a concentration of 6wt% in 4 ,4'-N,N'-dicarbazole-biphenyl (CBP) as the host material, and introduced the hole blocking layer material 2,9-dimethyl 4,7-diphenyl-1,10- O-phenanthroline (BCP), the maximum external quantum efficiency of the green OLED obtained is 8%, and the power efficiency is 31lm/W, both of which are much higher than the electroluminescent light-emitting devices, which immediately aroused people's widespread attention to the light-emitting materials of heavy metal complexes .

In 2000, Forrest et al. [Adachi, Chihaya.Baldo, Marc A.Forrest, Stephen R.Thompson, Mark E., Appl.Phys.Lett., 2000,77,904] doped Ir(ppy) ₃ in the electron-transporting host In 3-phenyl-4-(1'-naphthyl)-5-phenyl-1,2,4-triazole (TAZ), the maximum power efficiency of the device was 40±2lm/W.

In 2003, Forrest (Holmes, R.J.Forrest, S.R.Tung, Y.-J.Kwong, R.C.and Brown, J.J.Garon, S.Thompson, M.E., Appl Phys Let, 2003, 82, 2422) realized the blue light iridium complex FIrpic , the maximum current efficiency and power efficiency of the device prepared by doping it in the host N,N'-dicarbazolyl-3,5-substituted benzene (mCP) were 7.5±0.8cd/A and 8.9±0.9lm/ W. the

However, the host materials used in the organic electrophosphorescent devices provided in the prior art do not have hole transport ability, and the stability of light emission is poor, and the brightness and luminous power cannot meet the requirements of use after doping with phosphorescent dyes.

Contents of the invention

The technical problem to be solved by the present invention is to provide a host material with good stability, high luminous intensity and high current efficiency, a preparation method thereof, and an organic electrophosphorescent device comprising the host material. the

In order to solve the above technical problems, the invention provides a compound shown in formula I:

Wherein, X is S or O; Ar is the substituent shown in formula II or formula III:

A preparation method of the compound shown in formula 1, comprising:

The compound shown in formula IV or formula V is mixed with the compound shown in formula VI and the carbonate of alkali metal in an organic solvent, and a Suzuki coupling reaction occurs under the action of a catalyst to obtain a crude product;

The crude product is subjected to reflux and extraction operations, and the extract is dried and then subjected to silica gel column chromatography to obtain the compound shown in formula I;

Wherein X is O or S, and _X is F, Cl, Br or I.

Preferably, the catalyst is tetrakis(triphenylphosphine)palladium. the

Preferably, the organic solvent is tetrahydrofuran. the

Preferably, the mass ratio of the compound represented by the formula IV or V to the compound represented by the formula VI is: (3.5~6):(3~4). the

Preferably, the mass ratio of the catalyst to the compound represented by formula VI is (0.6~0.7):(3~4). the

An organic electrophosphorescent device, comprising:

Glass;

a substrate attached to said glass;

a hole injection layer disposed on the substrate;

a hole transport layer disposed on the hole injection layer;

a light emitting layer disposed on the hole transport layer;

a hole blocking layer disposed on the light-emitting layer;

an electron transport layer disposed on the hole blocking layer;

a cathode layer disposed on the electron transport layer;

Wherein, the light-emitting layer is composed of a host material and a dopant material, and the host material is a compound shown in formula 1;

Wherein, X is S or O; Ar is the substituent shown in formula II or formula III:

Preferably, the dopant material is an iridium complex of a cyclometal ligand. the

Preferably, the iridium complex of the cyclometal ligand is one or more of the compounds shown in formula 1 to formula 4:

Preferably, the doping ratio of the doping material in the host material is 3wt%-15wt%. the

The compound represented by formula I provided by the present invention has a dibenzoheterocyclic structure, wherein the heterocyclic ring is a furan structure or a thiophene structure, and has a spirobifluorene substituent represented by formula II or formula III, and the compound represented by formula I When the compound shown is used as the host material, the dibenzoheterocyclic structure has hole transport ability, and the spirobifluorene substituent has good stability, so that the compound shown in formula I has better electrophoresis than the prior art. Luminous properties. the

The present invention also provides the preparation method of the compound shown in the described I, the compound halogenated spirobifluorene compound shown in formula IV or formula V is reacted with the dibenzoheterocyclic boronic acid shown in formula VI, because formula IV Or the formula V contains a halogen, and the compound shown in the formula VI has a boronic acid group, so the reaction is a Suzuki coupling reaction. Because it is a Suzuki coupling reaction, the reaction conditions are mild and the yield is high, which is suitable for large-scale industrial production. the

The present invention also provides an organic electrophosphorescent device comprising a compound represented by formula I, comprising: glass; a substrate attached to the glass; a hole injection layer disposed on the substrate; disposed on the The hole transport layer on the hole injection layer; the light emitting layer arranged on the hole transport layer; the hole blocking layer arranged on the light emitting layer; the electron transport layer arranged on the hole blocking layer layer; a cathode layer arranged on the electron transport layer; the light-emitting layer is formed by phosphorescent dye doping in the host material formed by the compound shown in Formula I, because the compound shown in Formula I has a dibenzoheterocycle group and spirobifluorene group, so on the basis of both hole transport properties, the stability of the organic electrophosphorescent device is increased, and the highest brightness, current efficiency and power efficiency are improved. Through the Keithley source measurement system detection of silicon photodiodes, the organic electrophosphorescent device provided by the present invention has a maximum current efficiency of 23.5cd/A when the phosphorescent device emits blue light, and a maximum current efficiency of 64cd/A when the phosphorescent device emits green light. A, when emitting white light, the maximum current efficiency is 50cd/A, which is better than the existing technology. the

Description of drawings

The ultraviolet-visible absorption spectrogram of the host material that Fig. 1 embodiment of the present invention 3 provides;

The photoluminescence figure of the host material that Fig. 2 embodiment of the present invention 3 provides;

Fig. 3 structural representation of electroluminescence device of the present invention;

Figure 4 is the emission spectrum of the electroluminescent device of the present invention. the

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with the examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention rather than limiting the patent requirements of the present invention. the

The present invention provides a dibenzoheterocyclic spirobifluorene compound, which has the structure shown in formula I:

Wherein, X is O or S; Ar is a substituent shown in formula II or formula III. the

In the structure shown in formula I, the dibenzoheterocyclic structure has a structure similar to that of carbazole, so it has excellent hole transport ability, which increases the transmission speed of holes in the host material, thereby improving the current efficiency and luminescence strength. However, the spirobifluorene substituents shown in formula II and formula III have two symmetrical host fluorene structures, the electron and hole transport ability has been greatly improved, the luminescent properties of the host fluorene have been preserved, and the ion in the conjugated structure The domain π bond makes the fluorescence enhanced, that is, the emission spectrum is red-shifted relative to the absorption spectrum, the energy is reduced, and the oscillator strength is enhanced, and its stability is further enhanced due to the symmetrical bifluorene structure. In summary, the compound represented by formula I having a benzothiophene or benzofuran structure and a spirobifluorene structure meets the characteristics of a bipolar carrier transport material. Good stability, high luminous intensity and high current efficiency. the

The present invention also provides a preparation method of the compound shown in formula I, comprising:

A preparation method of the compound shown in formula 1, comprising:

The compound shown in formula IV or formula V is mixed with the compound shown in formula VI and the carbonate of alkali metal in an organic solvent, and a Suzuki coupling reaction occurs under the action of a catalyst to obtain a crude product;

The crude product is subjected to reflux and extraction operations, and the extract is dried and then subjected to silica gel column chromatography to obtain the compound shown in formula I;

Wherein X is O or S, and _X is F, Cl, Br or I.

Owing to being mixed in the organic solvent by the compound shown in IV or formula V and the carbonate shown in formula VI and alkali metal, can find out that actually is between benzene ring and benzene ring by observing the structural formula of raw material compound Coupling reaction, since the compound shown in formula I is used for organic electrophosphorescent devices, so harsh reaction conditions cannot be used in the preparation process, so the present invention uses Suzuki coupling reaction to prepare during preparation, the conditions Gentle and high yield. In the Suzuki coupling reaction, the catalyst is preferably a palladium-based catalyst, more preferably tetrakis(triphenylphosphine)palladium (Pd(PPh ₃ ) ₄ ). The mass ratio of the catalyst to the compound represented by formula VI is preferably (0.6~0.7):(3~4). The mass ratio of the compound represented by the formula IV or V to the compound represented by the formula VI is preferably: (3.5-6): (3-4). The organic solvent is preferably tetrahydrofuran.

The present invention also provides an organic electrophosphorescent device, comprising:

Glass;

a substrate attached to said glass;

a hole injection layer disposed on the substrate;

a hole transport layer disposed on the hole injection layer;

a light emitting layer disposed on the hole transport layer;

a hole blocking layer disposed on the light-emitting layer;

an electron transport layer disposed on the hole blocking layer;

a cathode layer disposed on the electron transport layer;

Wherein, the light-emitting layer is composed of a host material and a dopant material, and the host material is a compound shown in Formula 1. the

The light-emitting layer material used in the organic electrophosphorescent device provided by the present invention is formed by doping a dopant material in a host material, the dopant material is an organic phosphorescent dye, and the host material is formed by a compound shown in formula I Body material. As shown in Figure 3, the organic electrophosphorescent device provided for the embodiment of the present invention includes: glass and substrate 1, hole injection layer 2, hole transport layer 3, light emitting layer 4, hole blocking layer 5, electron Transport layer 6, cathode layer 7. the

According to the present invention, the doped organic phosphorescent dye is preferably an iridium complex of a ring metal ligand; more preferably a compound represented by formula 1 to formula 3, that is, green-emitting Ir(ppy) ₃ , Ir(ppy ) ₂ (acac) or FIrpic with blue light:

The doping ratio of the doping material in the host material is 8wt%-15wt%. Wherein the doping weight ratio of the green phosphorescent dye is preferably 8wt%-10wt%, and the doping ratio of the blue phosphorescent dye is preferably 8wt%-15wt%. the

More preferably, the present invention also provides an organic electrophosphorescent device with two light-emitting layers. Different phosphorescent dyes are doped in the two light-emitting layers, which can excite white light. One of them is preferably doped with a blue phosphorescent dye, namely For the compound shown in formula 3, the other layer is preferably doped with yellow phosphorescent dye PO-01, and its structure is shown in formula IV. The doping amount of the blue phosphorescent dye shown in the formula 3 is 8wt%-15wt%, and the doping amount of the PO-01 is 3%-5%. the

The following are specific examples of the present invention, which have set forth the scheme of the present invention in detail: the raw materials used in the examples are all commercially available. the

Example 1

Preparation of 4-2-spirobifluorenyl-dibenzofuran (abbreviated as Host1)

Add 4.00 g of 2-bromospirobifluorene and 3.20 g of 4-dibenzofuran boronic acid into a 50 mL flask, add catalyst Pd(PPh ₃ ) ₄ 650 mg, THF 42 mL, 2M K ₂ CO ₃ solution 14 mL, argon Reflux at 70°C for 24 hours under air protection, extract with dichloromethane after cooling, dry the organic layer with anhydrous sodium sulfate and spin dry, pass through the column with dichloromethane/petroleum ether = 1:5, and spin dry to obtain 4.25 g of the target compound , yield 87.3%. ¹ H NMR (400MHz, CDCl ₃ )δ(ppm):8.00-8.07(m,2H),7.91(d,J=7.6Hz,2H),7.82-7.87(m,3H),7.36–7.46(m, 6H),7.27–7.34(m,2H),7.12–7.17(m,4H),6.84(d,J=7.6Hz,2H),6.79(d,J=7.6Hz,1H). ¹³ C NMR(100 MHz, CDCl ₃ ) δ (ppm): 155.9, 153.1, 149.4, 149.1, 148.7, 141.8, 141.5, 141.3, 135.9, 128.7, 127.9, 127.8, 127.7, 127.1, 126.6, 125.6, 124.7, 124.2, 123.4. 122.6, 120.6, 120.1, 120.0, 119.5, 111.7, 66.1. MS (EI): m/z 482.22 (M ⁺ ).

Example 2

Preparation of 4-2-spirobifluorenyl-dibenzothiophene (abbreviated as Host2)

Using a method similar to Example 1, 4-2-spirobifluorenyl-dibenzothiophene can be prepared using 2-bromospirobifluorene and 4-dibenzothiophene boronic acid as raw materials, with a yield of 92.2%. ¹ H NMR (400MHz, CDCl ₃ )δ(ppm): 8.11(t, J=4.8Hz, 1H), 8.03(d, J=7.6Hz, 1H), 7.98(d, J=8.0Hz, 1H), 7.90(d,J=7.6Hz,1H),7.80-7.85(m,3H),7.75(t,J=5.2Hz,1H),7.33-7.45(m,6H),7.32(d,J=7.6Hz ^13C NMR (100MHz, CDCl ₃ )δ(ppm): 149.6, 149.1, 148.5, 141.8, 141.6, 141.3, 140.1, 139.4, 138.5, 136.8, 136.1, 135.6, 128.0, 127.8, 127.7, 126.7, 126.6, 124.2, 124.2, ,122.5,121.6,120.3,120.1,120.0,66.0.MS(EI):m/z 498.08(M ⁺ ).

Example 3

Preparation of 4-4-spirobifluorenyl-dibenzofuran (abbreviated as Host3)

Using a method similar to that of Example 1, the raw materials were 4-bromospirobifluorene and 4-dibenzofuranboronic acid. 4-4-spirobifluorenyl-dibenzofuran can be obtained. Yield 75.4%. ¹ H NMR(400MHz, CDCl ₃ )δ(ppm):8.11(d,J=7.6Hz,1H),8.06(d,J=7.6Hz,1H),7.87(d,J=7.6Hz,2H), 7.67(d,J=7.6Hz,1H),7.51–7.57(m,2H),7.36–7.47(m,5H),7.13-7.24(m,3H),6.80-6.97(m,5H),6.68- 6.74(m,2H) ^.13C NMR(100MHz,CDCl ₃ )δ(ppm):156.3,153.9,149.5,149.0,148.9,141.9,141.7,141.5,139.6,131.4,130.2,128.4,127.8,127.7,127.5 ,127.4,127.3,125.1,124.7,124.1,123.7,123.6,123.0,122.8,122.4,120.7,120.3,120.0,112.1,65.7.MS(EI):m/z 482.23(M ⁺ ).

Example 4

Preparation of 4-4-spirobifluorenyl-dibenzothiophene (abbreviated as Host4)

Using a method similar to that of Example 1, 4-bromospirobifluorene and 4-dibenzothiophene were selected as raw materials to obtain 4-4-spirobifluorenyl-dibenzothiophene. Yield 79.9%. ¹ H NMR(400MHz, CDCl ₃ )δ(ppm):8.32(d,J=7.6Hz,1H),8.27(d,J=7.6Hz,1H),7.87(d,J=7.2Hz,2H), 7.79(d,J=7.6Hz,1H),7.70(t,J=7.6Hz,1H),7.66(d,J=6.8Hz,1H),7.44-7.54(m,2H),7.40(t,J =7.2Hz,2H),7.34 (d,J=7.2Hz,1H),7.36–7.47(m,5H),7.13-7.24(m,3H),6.80-6.97(m,5H),6.69(d, J=7.2Hz,1H),6.57(d,J=7.6Hz,1H). ¹³ C NMR(100MHz,CDCl ₃ )δ(ppm):149.7,149.0,148.9,148.7,142.0,141.6,141.1,140.2, 140.0, 139.0, 135.8, 135.1, 129.2, 128.0, 127.8, 127.7, 127.6, 127.4, 127.1, 126.8, 125.0, 124.4, 124.2, 124.1, 123.8, 123.6, 122.9, 122.6, 120.08, MS EI): m/z 498.09(M ⁺ ).

Example 5

Fabrication of electrophosphorescent devices

As shown in Figure 3, the electrophosphorescent device using the present invention as the main material of the light-emitting layer can include glass and conductive glass (ITO) substrate layer 1, hole injection layer 2 (molybdenum trioxide MoO ₃ ), hole transport layer 3(4,4'-bis(N-phenyl-N-naphthyl)-biphenyl NPB), exciton blocking layer 4(4,4',4″-tris(carbazol-9-yl)triphenylamine TCTA) light emitting layer 5 (the host material in claim 1 is doped with the phosphorescent iridium complex in claim 2), hole blocking layer 6 (1,3,5-tri(1-phenyl-1H-benzo imidazol-2-yl) benzene TPBi), electron injection layer 6 (tris-8-hydroxyquinolate lithium Liq), cathode layer 7 (aluminum).

The electroluminescent device can be fabricated by methods known in the art, such as the method disclosed in the reference (Adv. Mater. 2003, 15, 277.). The specific method is: under high vacuum conditions, 10nm MoO ₃ , 80nm NPB, 20nm light-emitting layer, 40nm TPBi, 2nm Liq and 100nm Al are sequentially evaporated on the cleaned conductive glass (ITO) substrate. . The device shown in Figure 3 is made by this method, and the structures of various devices are as follows:

Device 1 (D1):

ITO/MoO ₃ (10nm)/NPB(80nm)/TCTA(5nm)/HOST3:FIrpic 8wt%(20nm)/TPBi(40nm)/Liq(2nm)/Al(100nm)

Device 2 (D2):

ITO/MoO ₃ (10nm)/NPB(80nm)/TCTA(5nm)/HOST4:FIrpic 8wt%(20nm)/TPBi(40nm)/Liq(2nm)/Al(100nm)

Device 3 (D3):

ITO/MoO ₃ (10nm)/NPB(35nm)/TCTA(10nm)/HOST1:Ir(ppy) ₂ acac 8wt%(15nm)/TPBi(65nm)/Liq(20nm)/Al (100nm)

Device 4 (D4):

ITO/MoO ₃ (10nm)/NPB(35nm)/TCTA(10nm)/HOST2:Ir(ppy) ₂ acac 8wt%(15nm)/TPBi(65nm)/Liq(20nm)/Al(100nm)

Device 5 (D5):

ITO/MoO ₃ (10nm)/NPB(35nm)/TCTA(10nm)/HOST3:Ir(ppy) ₂ acac 8wt%(15nm)/TPBi(65nm)/Liq(20nm)/Al(100nm)

Device 6 (D6):

ITO/MoO ₃ (10nm)/NPB(35nm)/TCTA(10nm)/HOST4:Ir(ppy) ₂ acac 8wt%(15nm)/TPBi(65nm)/Liq(20nm)/Al(100nm)

Device 7 (D7):

ITO/MoO ₃ (10nm)/NPB(80nm)/TCTA(10nm)/HOST3:PO-013wt%(1nm)/HOST4:FIrpic 8wt%(19nm)/TPBi(40nm)/Liq(2nm)/Al(100nm )

Device 8 (D8):

ITO/MoO ₃ (10nm)/NPB(80nm)/TCTA(10nm)/HOST4:PO-013wt%(1nm)/HOST4:FIrpic 8wt%(19nm)/TPBi(40nm)/Liq(2nm)/Al(100nm )

The current-brightness-voltage characteristics of the device were completed by a Keithley source-measurement system (Keithley 2400 Sourcemeter, Keithley 2000 Currentmeter) with a calibrated silicon photodiode, and the electroluminescence spectrum was measured by a PR655 spectrometer from Photo research company. Complete in room temperature atmosphere. the

The performance data of the device is shown in the table below:

Device 1-2 emits blue light, and the electroluminescence performance is significantly higher than that of the comparative literature (C.Han, G.Xie, J.Li, Z.Zhang, H.Xu, Z.Deng, Y.Zhao, P.Yan and S . Liu, Chem. Eur. J. 2011, 17, 8947-8956.). The maximum current efficiency is as high as 23.5 canteras per ampere, which is the highest so far. The corresponding green performance of devices 3-6 is much higher than that of the comparison devices. Devices 7-8 emit white light with a maximum current efficiency of 50 canteras per ampere, one of the highest values currently available for such host materials. Therefore, compared with other host materials, the host material of the present invention has obtained excellent electroinduced Luminescent properties are beneficial to the development of high-efficiency full-color displays. the

A dibenzoheterocyclic spirobifluorene compound provided by the present invention and its preparation method and an organic electrophosphorescent device have been introduced in detail above. In this paper, specific examples are used to carry out the principle and implementation of the present invention. To illustrate, the descriptions of the above embodiments are only used to help understand the method of the present invention and its core idea. Several improvements and modifications are made, which also fall within the protection scope of the claims of the present invention. the

Claims (10)

1. A compound shown in formula I:

Wherein, X is S or O; Ar is the substituent shown in formula II or formula III:

2. A preparation method for the compound shown in formula 1, characterized in that, comprising: Mixing the compound shown in formula IV or formula V with the compound shown in formula VI and alkali metal carbonate in an organic solvent, and a Suzuki coupling reaction occurs under the action of a catalyst to obtain a crude product; The crude product was refluxed and extracted, and the extract was dried and subjected to silica gel column chromatography to obtain the compound shown in formula I;

Wherein X is O or S, and _X is F, Cl, Br or I. 3. preparation method according to claim 2 is characterized in that, described catalyst is tetrakis (triphenylphosphine) palladium. 4. preparation method according to claim 2 is characterized in that, described organic solvent is THF. 5. The preparation method according to claim 2, wherein the mass ratio of the compound represented by the formula IV or V to the compound represented by the formula VI is: (3.5~6): (3~4) . 6 . The preparation method according to claim 2 , wherein the mass ratio between the catalyst and the compound represented by formula VI is (0.6~0.7):(3~4). 7. An organic electrophosphorescent device, characterized in that it comprises: Glass; a substrate attached to said glass; a hole injection layer disposed on the substrate; a hole transport layer disposed on the hole injection layer; a light emitting layer disposed on the hole transport layer; a hole blocking layer disposed on the light-emitting layer; an electron transport layer disposed on the hole blocking layer; a cathode layer disposed on the electron transport layer; Wherein, the light-emitting layer is composed of a host material and a dopant material, and the host material is a compound shown in Formula 1;

Wherein, X is S or O; Ar is the substituent shown in formula II or formula III:

8. The organic electrophosphorescent device according to claim 7, wherein the dopant material is an iridium complex of a ring metal ligand. 9. The organic electrophosphorescent device according to claim 8, wherein the iridium complex of the ring metal ligand is one or more of the compounds shown in formula 1 to formula 4:

10 . The organic electrophosphorescent device according to claim 9 , wherein the doping ratio of the dopant material in the host material is 3wt%˜15wt%.

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