Phenanthroline derivative for organic electroluminescent device

Abstract

The present invention discloses a phenanthroline derivative is represented by the following formula(I), the organic EL device employing the phenanthroline derivative as hole blocking electron transport material, electron transport material can display good performance like as lower driving voltage and power consumption, increasing efficiency and half-life time. ##STR00001##
Wherein Ar, X, m, n, p and R.sub.1 to R.sub.3 are the same definition as described in the present invention.

Claims

1. A phenanthroline derivative represented by the following formula(I): ##STR00022## wherein L represents a single bond, or a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, m represents an integer of 0 to 6, n represents an integer of 0 to 4, p represents an integer of 0 to 4 and X independently represents a atom or group consisting from O, S, N(R.sub.4); Ar is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, provided that Ar represents a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted phenanthrenyl group, a substituted or unsubstituted pyrenyl group, and a substituted or unsubstituted chrysenyl group; R.sub.1 to R.sub.4 are independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 30 carbon atoms.

2. The phenanthroline derivative according to claim 1, wherein Ar is selected from a group consisting of ##STR00023##

3. The phenanthroline derivative according to claim 1, wherein the phenanthroline derivative formula(I) is represented by the following formula(II): ##STR00024## wherein L represents a single bond, or a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, n represents an integer of 0 to 4, p represents an integer of 0 to 4 and X independently represents a atom or group consisting from O, S, N(R.sub.4); Ar is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, provided that Ar represents a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted phenanthrenyl group, a substituted or unsubstituted pyrenyl group, and a substituted or unsubstituted chrysenyl group; R.sub.2 to R.sub.4 are independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 30 carbon atoms.

4. The phenanthroline derivative according to claim 1, wherein Ar is selected from a group consisting of ##STR00025##

5. A organic electroluminescent device comprising a pair of electrodes consisting of a cathode and an anode and between the pairs of electrodes comprising at least a layer of the phenanthroline derivative with a general formula(I) according to claim 1.

6. The organic electroluminescent device according to claim 5, wherein the electron transport layer comprising the phenanthroline derivative with a general formula(I).

7. The organic electroluminescent device according to claim 5, wherein the hole blocking electron transport layer comprising the phenanthroline derivative with a general formula(I).

8. The organic electroluminescent device according to claim 5, wherein the hole blocking layer Ar is selected from a group consisting of ##STR00026##

9. The organic electroluminescent device according to claim 6, wherein the electron transport layer comprising lithium or 8-hydroxyuinolinolato-lithium.

10. The phenanthroline derivative according to claim 1, wherein the phenanthroline derivative is selected from a group consisting of ##STR00027## ##STR00028## ##STR00029## ##STR00030##

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The FIGURE show one example of organic EL device in the present invention, and 6 is transparent electrode, 13 is metal electrode, 7 is hole injection layer which is deposited onto 6, 8 is hole transport layer which is deposited onto 7, 9 is fluorescent or phosphorescent emitting layer which is deposited onto 8, 10 is hole blocking layer which is deposited onto 9, 11 is electron transport layer which is deposited onto 10, 12 is electron injection layer which is deposited on to 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(2) What probed into the invention is the phenanthroline derivative and organic EL device using the phenanthroline derivative. Detailed descriptions of the production, structure and elements will be provided in the following to make the invention thoroughly understood. Obviously, the application of the invention is not confined to specific details familiar to those who are skilled in the art. On the other hand, the common elements and procedures that are known to everyone are not described in details to avoid unnecessary limits of the invention. Some preferred embodiments of the present invention will now be described in greater detail in the following. However, it should be recognized that the present invention can be practiced in a wide range of other embodiments besides those explicitly described, that is, this invention can also be applied extensively to other embodiments, and the scope of the present invention is expressly not limited except as specified in the accompanying claims.

(3) In a first embodiment of the present invention, the phenanthroline derivative which can be used as hole blocking electron transport material (HBETM) or electron transport material (ETM) for organic EL device are disclosed. The mentioned phenanthroline derivative represented by the following formula(I)

(4) ##STR00003##
wherein L represent a single bond, or a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, m represent an integer of 0 to 6, n represent an integer of 0 to 4, p represent an integer of 0 to 4 and X independently represent a atom or group consisting from O, S, N(R.sub.4); Ar is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, provided that Ar represent a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted phenanthrenyl group, a substituted or unsubstituted pyrenyl group, and a substituted or unsubstituted chrysenyl group; R.sub.1 to R.sub.4 independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 30 carbon atoms.

(5) According to the above-mentioned the phenanthroline derivative formula(I) wherein Ar represented the follows:

(6) ##STR00004##

(7) According to the above-mentioned the phenanthroline derivative formula(I) represented by the following formula(II):

(8) ##STR00005##
wherein L represent a single bond, or a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, n represent an integer of 0 to 4, p represent an integer of 0 to 4 and X independently represent a atom or group consisting from O, S, N(R.sub.4); Ar is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, provided that Ar represent a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted phenanthrenyl group, a substituted or unsubstituted pyrenyl group, and a substituted or unsubstituted chrysenyl group; R.sub.2 to R.sub.4 independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 30 carbon atoms.

(9) According to the above-mentioned the phenanthroline derivative formula(II), wherein Ar represented the follows:

(10) ##STR00006##

(11) In this embodiment, some phenanthroline derivatives are shown below:

(12) ##STR00007## ##STR00008## ##STR00009## ##STR00010##

(13) Detailed preparation for the phenanthroline derivative in the present invention could be clarified by exemplary embodiments, but the present invention is not limited to exemplary embodiments. EXAMPLE 1˜3 show the preparation for examples of the phenanthroline derivative in the present invention. EXAMPLE 4 show the fabrication of organic EL device and I-V-B, half-life time of organic EL device testing report.

Example 1

Synthesis of EX1

Synthesis of 9-bromo-10-phenylanthracene

(14) ##STR00011##

(15) A mixture of 40 g (119 mmol) of 9,10-dibromoanthracene, 16 g (131 mmol) of phenylboronic acid, 1.38 g (1.2 mmol) of Pd(PPh.sub.3).sub.4, 120 ml of 2M Na.sub.2CO.sub.3, 150 ml of EtOH and 450 ml toluene was degassed and placed under nitrogen, and then heated at 100° C. for 12 h. After finishing the reaction, the mixture was allowed to cool to room temperature. The organic layer was extracted with ethyl acetate and water, dried with anhydrous magnesium sulfate, the solvent was removed and the residue was purified by column chromatography on silica to give product (17.8 g, 53.6 mmol, 45%) as a yellow solid.

Synthesis of 4,4,5,5-tetramethyl-2-(4-(10-phenylanthracen-9-yl)phenyl)-1,3,2-dioxaborolane

(16) ##STR00012##

(17) A mixture of 30 g (90 mmol) of 9-bromo-10-phenylanthracene, 29.7 g (90 mmol) of 1,4-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-benzene, 1.04 g (0.9 mmol) of Pd(PPh.sub.3).sub.4, 90 ml of 2M Na.sub.2CO.sub.3, 150 ml of EtOH and 450 ml toluene was degassed and placed under nitrogen, and then heated at 100° C. for 12 h. After finishing the reaction, the mixture was allowed to cool to room temperature. The organic layer was extracted with ethyl acetate and water, dried with anhydrous magnesium sulfate, the solvent was removed and the residue was purified by column chromatography on silica to give product (2.5 g, 5.5 mmol, 6.1%) as a yellow solid.

Synthesis of 2-chloro-4,7-diphenyl-9-(4-(10-phenylanthracen 9-yl)phenyl)-1,10-phenanthroline

(18) ##STR00013##

(19) A mixture of 6.8 g (16.9 mmol) of 2,9-dichloro-4,7-diphenyl-1,10-phenanthroline, 7.7 g (16.9 mmol) of 4,4,5,5-tetramethyl-2-(4-(10-phenylanthracen-9-yl)phenyl)-1,3,2-dioxaborolane, 196 mg (0.17 mmol) of Pd(PPh.sub.3).sub.4, 17 ml of 2M Na.sub.2CO.sub.3, 50 ml of EtOH and 150 ml toluene was degassed and placed under nitrogen, and then heated at 100° C. for 12 h. After finishing the reaction, the mixture was allowed to cool to room temperature. The organic layer was extracted with ethyl acetate and water, dried with anhydrous magnesium sulfate, the solvent was removed and the residue was purified by column chromatography on silica to give product (6 g, 8.6 mmol, 50.8%) as a yellow solid.

Synthesis of EX1

(20) ##STR00014##

(21) A mixture of 6 g (8.6 mmol) of 2-chloro-4,7-diphenyl-9-(4-(10-phenylanthracen-9-yl)phenyl)-1,10-phenanthroline, 4.1 g (10.3 mmol) of 1-phenyl-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-1H-benzo[d] imidazole, 100 mg (0.086 mmol) of Pd(PPh.sub.3).sub.4, 8.6 ml of 2M Na.sub.2CO.sub.3, 40 ml of EtOH and 120 ml toluene was degassed and placed under nitrogen, and then heated at 100° C. for 12 h. After finishing the reaction, the mixture was allowed to cool to room temperature. The organic layer was extracted with ethyl acetate and water, dried with anhydrous magnesium sulfate, the solvent was removed and the residue was purified by column chromatography on silica to give EX1 (4.8 g, 5.2 mmol, 60%) as a yellow solid. MS (m/z, FAB.sup.+): 929.9; .sup.1H NMR (CDCl.sub.3, 500 MHz): chemical shift (ppm) 8.66 (d, 2H), 8.46 (d, 2H), 8.23 (s, 1H), 8.1 (s, 1H), 7.9˜7.82 (m, 5H), 7.78˜7.68 (m, 6H), 7.66˜7.49 (m, 16H), 7.48˜7.42 (m, 2H), 7.42˜7.3 (m, 9H).

Example 2

Synthesis of EX3

Synthesis of 2-(4-(10-(naphthalen-1-yl)anthracen-9-yl)phenyl)-4,7-diphenyl-9-(4-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl)-1,10-phenanthroline (EX3)

(22) ##STR00015##

(23) 2-chloro-9-(4-(10-(naphthalen-1-yl)anthracen-9-yl)phenyl)-4,7-diphenyl-1,10-phenanthroline instead of 2-chloro-4,7-diphenyl-9-(4-(10-phenylanthracen-9-yl)phenyl)-1,10-phenanthroline, except for using the same method as in synthesis example 1, the desired compound of 2-(4-(10-(naphthalen-1-yl)anthracen-9-yl)phenyl)-4,7-diphenyl-9-(4-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl)-1,10-phenanthroline (5 g, yield=64%) was obtained. MS (m/z, FAB.sup.+): 979.8; .sup.1H NMR (CDCl.sub.3, 500 MHz): chemical shift (ppm) 8.68 (d, 2H), 8.45 (d, 2H), 8.25 (s, 1H), 8.12 (s, 1H), 7.94˜7.84 (m, 6H), 7.80˜7.69 (m, 7H), 7.66˜7.51 (m, 16H), 7.48˜7.44 (m, 2H), 7.42˜7.28 (m, 9H).

Example 3

Synthesis of EX8

Synthesis of 2-(4-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)-4,7-diphenyl-9-(4-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl)-1,10-phenanthroline

(24) ##STR00016##

(25) 2-chloro-9-(4-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)-4,7-diphenyl-1,10-phenanthroline instead of 2-chloro-4,7-diphenyl-9-(4-(10-phenylanthracen-9-yl)phenyl)-1,10-phenanthroline, except for using the same method as in synthesis example 1, the desired compound of 2-(4-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)-4,7-diphenyl-9-(4-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl)-1,10-phenanthroline (4.8 g, yield=61%) was obtained. MS (m/z, FAB.sup.+): 979.8; .sup.1H NMR (CDCl.sub.3, 500 MHz): chemical shift (ppm) 8.67 (d, 2H), 8.44 (d, 2H), 8.24 (s, 1H), 8.12 (s, 1H), 7.92˜7.82 (m, 6H), 7.80˜7.68 (m, 7H), 7.66˜7.50 (m, 16H), 7.48˜7.43 (m, 2H), 7.42˜7.32 (m, 9H).

General Method of Producing Organic EL Device

(26) ITO-coated glasses with 9˜12 ohm/square in resistance and 120˜160 nm in thickness are provided (hereinafter ITO substrate) and cleaned in a number of cleaning steps in an ultrasonic bath (e.g. detergent, deionized water). Before vapor deposition of the organic layers, cleaned ITO substrates are further treated by UV and ozone. All pre-treatment processes for ITO substrate are under clean room (class 100).

(27) These organic layers are applied onto the ITO substrate in order by vapor deposition in a high-vacuum unit (10.sup.−7 Torr), such as: resistively heated quartz boats. The thickness of the respective layer and the vapor deposition rate (0.1˜0.3 nm/sec) are precisely monitored or set with the aid of a quartz-crystal monitor. It is also possible, as described above, for individual layers to consist of more than one compound, i.e. in general a host material doped with a dopant material. This is achieved by co-vaporization from two or more sources.

(28) Dipyrazino[2,3-f:2,3-]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN) is used as hole injection layer in this organic EL device, N,N-Bis(naphthalene-1-yl)-N,N-bis(phenyl)-benzidine (NPB) is most widely used as the hole transporting layer, 10,10-Dimethyl-12-(4-(pyren-1-yl)phenyl)-10H-indeno[1,2-b]triphenylene(PT-312, US20140175384) is used as blue emitting host in organic EL device and N1,N1,N6,N6-tetram-tolylpyrene-1,6-diamine (D1) is used as blue guest; 2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-13-yl)-4,6-diphenyl-1,3,5-triazine (HB1), 2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-12-yl)-4,6-diphenyl-1,3,5-triazine (HB2) and HB3 (see the following chemical structure) are used as hole blocking material (HBM); 4,7-diphenyl-2-(4-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl)-1,10-phenanthroline (ET1) and 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (ET2) are used as electron transporting material (ET1) to co-deposit with 5% Li, or co-deposit with 8-hydroxyquinolato-lithium (LiQ) in organic EL device for comparison. The prior art of OLED materials for producing standard organic EL device control and comparable material in this invention shown its chemical structure as follows:

(29) ##STR00017## ##STR00018## ##STR00019## ##STR00020##

(30) A typical organic EL device consists of low work function metals, such as Al, Mg, Ca, Li and K, as the cathode by thermal evaporation, and the low work function metals can help electrons injecting the electron transporting layer from cathode. In addition, for reducing the electron injection barrier and improving the organic EL device performance, a thin-film electron injecting layer is introduced between the cathode and the electron transporting layer. Conventional materials of electron injecting layer are metal halide or metal oxide with low work function, such as: LiF, LiQ, MgO, or Li.sub.2O. On the other hand, after the organic EL device fabrication, EL spectra and CIE coordination are measured by using a PR650 spectra scan spectrometer. Furthermore, the current/voltage, luminescence/voltage and yield/voltage characteristics are taken with a Keithley 2400 programmable voltage-current source. The above-mentioned apparatuses are operated at room temperature (about 25° C.) and under atmospheric pressure.

Example 4

(31) Using a procedure analogous to the above mentioned general method, fluorescent blue-emitting organic EL device having the following device structure I and II was produced (See FIGURE). Device I: ITO/HAT-CN (20 nm)/NPB (110 nm)/PT-312 doped 5% D1 (30 nm)/HBM/ETM doped 5% Li (35 nm)/Al (160 nm). Device II: ITO/HAT-CN (20 nm)/NPB (110 nm)/PT-312 doped 5% D1 (30 nm)/HBM/ETM co-deposit 50% LiQ (40 nm)/LiQ (1 nm)/Al (160 nm). The I-V-B (at 1000 nits) and half-life time of fluorescent blue-emitting organic EL device testing report as Table1 and Table2. The half-life time is defined that the initial luminance of 1000 cd/m.sup.2 has dropped to half.

(32) TABLE-US-00001 TABLE 1 ETM doped Voltage Efficiency Half-life time HBM 5% Li (V) (cd/A) CIE (y) (hour) HB1 ET1 6.5 3.5 0.188 130 HB1 ET2 6.3 3.7 0.189 130 HB1 EX1 4.5 5.2 0.181 250 HB1 EX3 4.0 6.2 0.183 360 HB1 EX8 4.0 6.0 0.182 350 — EX3 4.1 5.8 0.182 280 HB2 EX8 3.8 6.5 0.180 410

(33) TABLE-US-00002 TABLE 2 ETM co-deposit Voltage Efficiency Half-life HBM 50% LiQ (V) (cd/A) CIE (y) time(hour) HB3 ET1 6.9 3.8 0.187 160 HB3 ET2 6.8 4.1 0.186 180 HB3 EX1 5.2 5.8 0.183 280 HB3 EX3 4.5 6.1 0.182 350 HB3 EX8 4.4 6.2 0.183 380 — EX3 4.5 5.7 0.183 420 HB2 EX8 4.6 6.7 0.184 410

(34) In the above preferred embodiments for organic EL device test report (see Table 1 to Table 2), we show that the phenanthroline derivative with a general formula(I) used as hole blocking electron transport material or electron transport material for organic EL in the present invention display good performance than the prior art of organic EL materials such as U.S. Pat. No. 7,119,204, U.S. Pat. No. 7,282,586, U.S. Pat. No. 7,754,348, U.S. Pat. No. 7,982,213 and U.S. Pat. No. 8,114,529. More specifically, the organic EL device in the present invention use the phenanthroline derivative with a general formula(I) as electron transport material to collocate with hole blocking material such as HB1, HB2 and HB3 shown lower power consumption, higher efficiency and longer half-life time. Besides the organic EL device in the present invention use the phenanthroline derivative with a general formula(I) also can use as hole blocking electron transport material without collocate with hole blocking material and shown good performance than prior art of organic EL materials

(35) To sum up, the present invention discloses a phenanthroline derivative with a general formula(I) used as hole blocking electron transport material or electron transport material for organic EL device. The mentioned phenanthroline derivative are represented by the following formula(I)

(36) ##STR00021##
wherein L represent a single bond, or a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, m represent an integer of 0 to 6, n represent an integer of 0 to 4, p represent an integer of 0 to 4 and X independently represent a atom or group consisting from O, S, N(R.sub.4); Ar is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, provided that Ar represent a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted phenanthrenyl group, a substituted or unsubstituted pyrenyl group, and a substituted or unsubstituted chrysenyl group; R.sub.1 to R.sub.4 independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 30 carbon atoms.

(37) Obvious many modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the present invention can be practiced otherwise than as specifically described herein. Although specific embodiments have been illustrated and described herein, it is obvious to those skilled in the art that many modifications of the present invention may be made without departing from what is intended to be limited solely by the appended claims.