Compound and Organic Electronic Device Comprising the Same

Abstract

The present invention relates to an organic electronic device and a compound comprised therein wherein the compound is represented by the Formula (I): HAr-L-Ar.sub.1—(—R.sup.1).sub.m.

Claims

1. Organic electronic device comprising an anode, a cathode, a photoactive layer and an organic semiconductive layer, wherein the organic semiconductive layer is arranged between the photoactive layer and the cathode, wherein the organic semiconductive layer comprises a compound represented by the following formula (I):
HAr-L-Ar.sub.1—(—R.sup.1).sub.m  (I) wherein HAr is a group represented by one of the following formulas (II to IV) ##STR00052## wherein the asterisk symbol “*” represents the binding position of the group HAr to the moiety L and; wherein X may be the same or different from each other and are independently selected from O and S; L is selected from the group consisting of unsubstituted or substituted C.sub.6 to C.sub.24 arylene and unsubstituted or substituted C.sub.3 to C.sub.24 heteroarylene, wherein the one or more substituents, if present, are independently selected from the group consisting of hydrogen, C.sub.6 to C.sub.18 aryl, C.sub.3 to C.sub.25 heteroaryl, D, F, CN, C.sub.1 to C.sub.16 alkyl, C.sub.1 to C.sub.16 alkyl, C.sub.1 to C.sub.16 alkyl, C.sub.1 to C.sub.16 alkoxy, C.sub.1 to C.sub.17 alkoxy, C.sub.1 to C.sub.16 alkoxy, nitrile and —PO(R.sup.3).sub.2, wherein R.sup.3 are independently selected from C.sub.1 to C.sub.16 alkyl, C.sub.6 to C.sub.18 aryl or C.sub.3 to C.sub.25 heteroaryl; Ar.sub.1 is selected from the group consisting of C.sub.6 to C.sub.60 arylene, C.sub.3 to C.sub.50 heteroarylene containing at least one heteroatom selected from O, N, S, Si and P, and the following groups represented by the formulas V to VII; ##STR00053## and the one or more R.sup.1 and R.sup.2 are independently selected from the group consisting of hydrogen, C.sub.6 to C.sub.18 aryl, C.sub.3 to C.sub.25 heteroaryl, D, F, CN, C.sub.1 to C.sub.16 alkyl, C.sub.1 to C.sub.16 alkyl, C.sub.1 to C.sub.16 alkyl, C.sub.1 to C.sub.16 alkoxy, C.sub.1 to C.sub.16 alkoxy, C.sub.1 to C.sub.16 alkoxy, nitrile and —PO(R.sup.3).sub.2, wherein the group R.sup.3 is selected from C.sub.1 to C.sub.16 alkyl, C.sub.6 to C.sub.18 aryl and C.sub.3 to C.sub.25 heteroaryl; wherein m is an integer from 0 to 5; n is independently an integer from 0 to 4; and wherein if one or more of HAr, Ar.sup.1, L, R.sup.1, R.sup.2 and R.sup.3 and substituent on one or more of HAr, Ar.sup.1, and L is a carbon containing group comprising at least one carbon atom directly connected with at least one hydrogen atom, the hydrogen atoms comprised in the carbon-containing group may be partially or fully replaced by deuterium atoms and/or fluorine atoms.

2. Organic electronic device according to claim 1, wherein the organic semiconductive layer is an electron transport layer and/or an electron injection layer.

3. Organic electronic device according to claim 1, wherein the organic semiconductive layer further comprises a metal, a metal salt, an organic alkali metal complex or mixtures thereof.

4. Organic electronic device according to claim 1, wherein the organic semiconductive layer is non-emissive.

5. Organic electronic device according to claim 1, wherein the organic semiconductive layer is an auxiliary electron transport layer.

6. Organic electronic device according to claim 1, wherein L is selected from unsubstituted or substituted C.sub.6 to C.sub.24 arylene and unsubstituted or substituted C.sub.3 to C.sub.24 heteroarylene.

7. Organic electronic device according to claim 1, wherein Ar.sub.1 is independently selected from the group consisting of phenylene, napthylene, phenantrhylene, anthracenylene, fluoranthenylene, pyrenylene, fluoenylene, pyridinylene, bipyridinylene, terpyridinylene, phenanthrolinylene, pyrimidinylene, pyrazinylene, triazinylene, quinolinylene, benzoquinolinylene, quinoxalinylene, benzoquinoxalinylene, acridinylene, benzoacridinylene, dibenzoacridinylene, phenanthrolinylene, carbazolenylene, dibenzofuranenylene, dibenzothiophenylene, benzofuropyrimidinylene, benzothienopyrimidinylene.

8. Organic electronic device according to claim 1, wherein Ar.sub.1 is selected from the group of compounds represented by the formulas V to VII ##STR00054##

9. Organic electronic device according to claim 1, wherein R.sup.1 is independently selected from the group consisting of hydrogen, C.sub.6 to C.sub.18 aryl, C.sub.3 to C.sub.25 heteroaryl, F, CN and PO(R.sup.3).sub.2, wherein R.sup.3 is selected from C.sub.1 to C.sub.16 alkyl, C.sub.6 to C.sub.18 aryl and C.sub.3 to C.sub.25 heteroaryl.

10. Organic electronic device according to claim 1, wherein m is an integer from 1 to 4.

11. Compound represented by the following formula (I)
HAr-L-Ar.sup.1—(—R.sup.1).sub.m  (I) wherein HAr is a group represented by one of the following formulas (II to IV) ##STR00055## wherein the asterisk symbol “*” represents the binding position of the group HAr to the moiety L and; wherein X may be the same or different from each other and are independently selected from O and S; L is selected from the group consisting of unsubstituted or substituted C.sub.6 to C.sub.24 arylene and unsubstituted or substituted C.sub.3 to C.sub.24 heteroarylene, wherein the one or more substituents, if present, are independently selected from the group consisting of hydrogen, C.sub.6 to C.sub.18 aryl, C.sub.3 to C.sub.24 heteroaryl, D, F, CN, C.sub.1 to C.sub.16 alkyl, C.sub.1 to C.sub.16 alkyl, partially or fully deuterated C.sub.1 to C.sub.16 alkyl, C.sub.1 to C.sub.16 alkoxy, C.sub.1 to C.sub.17 alkoxy, C.sub.1 to C.sub.16 alkoxy, nitrile and —PO(R.sup.3).sub.2, wherein R.sup.3 are independently selected from C.sub.1 to C.sub.16 alkyl, C.sub.6 to C.sub.18 aryl or C.sub.3 to C.sub.25 heteroaryl; Ar.sub.1 is selected from the group consisting of C.sub.6 to C.sub.60 arylene, C.sub.3 to C.sub.50 heteroarylene containing at least one heteroatom selected from O, N, S, Si and P, and the following groups represented by the formulas V to VII; ##STR00056## and the one or more R.sup.1 and R.sup.2 are independently selected from the group consisting of hydrogen, C.sub.6 to C.sub.18 aryl, C.sub.3 to C.sub.25 heteroaryl, D, F, CN, C.sub.1 to C.sub.16 alkyl, C.sub.1 to C.sub.16 alkyl, C.sub.1 to C.sub.16 alkyl, C.sub.1 to C.sub.16 alkoxy, C.sub.1 to C.sub.16 alkoxy, partially or fully deuterated C.sub.1 to C.sub.16 alkoxy, nitrile and —PO(R.sup.3).sub.2, wherein the group R.sup.3 is selected from C.sub.1 to C.sub.16 alkyl, C.sub.6 to C.sub.18 aryl and C.sub.3 to C.sub.25 heteroaryl; m is an integer from 0 to 5; n is independently an integer from 0 to 4; and wherein if one or more of HAr, Ar.sup.1, L, R.sup.1, R.sup.2 and R.sup.3 and substituent on one or more of HAr, Ar.sup.1, and L is a carbon containing group comprising at least one carbon atom directly connected with at least one hydrogen atom, the hydrogen atoms comprised in the carbon-containing group may be partially or fully replaced by deuterium atoms and/or fluorine atoms. provided that if L is a trivalent group than the compound of formula (I) is not symmetrical; and provided that if Ar.sub.1 is a carbazolylene group than L is not phenylene.

12. Compound according to claim 11, wherein L is selected from unsubstituted or substituted C.sub.6 to C.sub.24 arylene and unsubstituted or substituted C.sub.3 to C.sub.24 heteroarylene.

13. Compound according to claim 11, wherein Ar.sub.1 is selected from the group of compounds represented by the formulas V to VII ##STR00057##

14. Compound according to claim 1, wherein R.sup.1 and R.sup.2 is independently selected from the group consisting of hydrogen, C.sub.6 to C.sub.18 aryl, C.sub.3 to C.sub.25 heteroaryl, F, CN and PO(R.sup.3).sub.2, wherein R.sup.3 is selected from C.sub.1 to C.sub.16 alkyl, C.sub.6 to C.sub.18 aryl and C.sub.3 to C.sub.25 heteroaryl.

15. Compound according to claim 11, wherein m is an integer from 1 to 4.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0179] These and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings, of which:

[0180] FIG. 1 is a schematic sectional view of an organic light-emitting diode (OLED), according to an exemplary embodiment of the present invention;

[0181] FIG. 2 is a schematic sectional view of an OLED, according to an exemplary embodiment of the present invention.

[0182] FIG. 3 is a schematic sectional view of a tandem OLED comprising a charge generation layer, according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION

[0183] Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The exemplary embodiments are described below, in order to explain the aspects of the present invention, by referring to the figures.

[0184] Herein, when a first element is referred to as being formed or disposed “on” or “onto” a second element, the first element can be disposed directly on the second element, or one or more other elements may be disposed there between. When a first element is referred to as being formed or disposed “directly on” or “directly onto” a second element, no other elements are disposed there between.

[0185] FIG. 1 is a schematic sectional view of an organic light-emitting diode (OLED) 100, according to an exemplary embodiment of the present invention. The OLED 100 includes a substrate 110, an anode 120, a hole injection layer (HIL) 130, a hole transport layer (HTL) 140, an emission layer (EML) 150, an electron transport layer (ETL) 160. The electron transport layer (ETL) 160 is formed on the EML 150. Onto the electron transport layer (ETL) 160, an electron injection layer (EIL) 180 is disposed. The cathode 190 is disposed directly onto the electron injection layer (EIL) 180.

[0186] Instead of a single electron transport layer 160, optionally an electron transport layer stack (EL) can be used.

[0187] FIG. 2 is a schematic sectional view of an OLED 100, according to another exemplary embodiment of the present invention. FIG. 2 differs from FIG. 1 in that the OLED 100 of FIG. 2 comprises an electron blocking layer (EBL) 14 and a hole blocking layer (HBL) 155.

[0188] Referring to FIG. 2, the OLED 100 includes a substrate 110, an anode 120, a hole injection layer (HIL) 130, a hole transport layer (HTL) 140, an electron blocking layer (EBL) 145, an emission layer (EML) 150, a hole blocking layer (HBL) 155, an electron transport layer (ETL) 160, an electron injection layer (EIL) 180 and a cathode electrode 190.

[0189] Preferably, the organic semiconducting layer comprising a compound of Formula (I) or consisting of a compound of Formula (I) may be an HBL or an ETL.

[0190] FIG. 3 is a schematic sectional view of a tandem OLED 200, according to another exemplary embodiment of the present invention. FIG. 3 differs from FIG. 2 in that the OLED 100 of FIG. 3 further comprises a charge generation layer (CGL) and a second emission layer (151).

[0191] Referring to FIG. 3, the OLED 200 includes a substrate no, an anode 120, a first hole injection layer (HIL) 130, a first hole transport layer (HTL) 140, a first electron blocking layer (EBL) 145, a first emission layer (EML) 150, a first hole blocking layer (HBL) 155, a first electron transport layer (ETL) 160, an n-type charge generation layer (n-type CGL) 185, a hole generating layer (p-type charge generation layer; p-type GCL) 135, a second hole transport layer (HTL) 141, a second electron blocking layer (EBL) 146, a second emission layer (EML) 151, a second hole blocking layer (EBL) 156, a second electron transport layer (ETL) 161, a second electron injection layer (EIL) 181 and a cathode 190.

[0192] Preferably, the organic semiconducting layer comprising a compound of Formula (I) or consisting of a compound of Formula (I) may be the first HBL, first ETL, n-type CGL and/or second HBL, second ETL.

[0193] While not shown in FIG. 1, FIG. 2 and FIG. 3, a sealing layer may further be formed on the cathode electrodes 190, in order to seal the OLEDs 100 and 200. In addition, various other modifications may be applied thereto.

[0194] Hereinafter, one or more exemplary embodiments of the present invention will be described in detail with, reference to the following examples. However, these examples are not intended to limit the purpose and scope of the one or more exemplary embodiments of the present invention.

Experimental Data

Preparation of compounds of formula D

Synthesis of 6-(4-bromophenyl)bis(benzofuro)[3,2-b:2′,3′-e]pyridine (3)

[0195] ##STR00034##

[0196] A flask was flushed with nitrogen and charged with (Z)-2-(4-bromobenzylidene)benzofuran-3(2H)-one (1) (13 g, 43.2 mmol), benzofuran-3(2H)-one (2) (5.8 g, 43.2 mmol), ammonium acetate (30 g, 389 mmol) and glacial acetic acid (195 mL). The mixture was heated to 120° C. under a nitrogen atmosphere for 17 h. After cooling down to 5° C. using an ice bath, the formed precipitate was collected by suction filtration and washed with acetic acid, water (until pH neutral) and methanol. The obtained solid was further purified by recrystallization from DMF. After drying, 9 g of 6-(4-bromophenyl)bis(benzofuro)[3,2-b:2′,3′-e]pyridine (3) were obtained.

Synthesis of 6-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)bis(benzofuro)[3,2-b:2′,3′-e]pyridine (4)

[0197] ##STR00035##

[0198] A flask was flushed with nitrogen and charged with 6-(4-bromophenyl)bis(benzofuro)[3,2-b:2′,3′-e]pyridine (6.9 g, 16.7 mmol), 4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bi(1,3,2-dioxaborolane) (3) (4.65 g, 18.3 mmol), Pd(dppf)Cl.sub.2 (0.37 g. 0.5 mmol), and potassium acetate (4.9 g, 50 mmol). Dry and deaerated DMF (60 mL) was added and the reaction mixture was heated to go ° C. under a nitrogen atmosphere for 21 h. After cooling down to 5° C. using an ice bath, the formed precipitate was collected by suction filtration and washed with DMF. The solid was dissolved in dichloromethane and the organic phase was washed with water three times. After drying over MgSO.sub.4, the organic phase was filtered through a pad of Florisil After rinsing with additional dichloromethane, the filtrate was concentrated to a minimal amount and n-hexane was added. The formed precipitate was isolated by suction filtration and washed with n-hexane. Further purification was achieved by recrystallization from DMF. After drying, 6 g of 6-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)bis(benzofuro)[3,2-b:2′,3′-e]pyridine (4) were obtained.

Synthesis of 6-(3-bromophenyl)bis(benzofuro)[3,2-b:2′,3′-e]pyridine (6)

[0199] ##STR00036##

[0200] 6-(3-bromophenyl)bis(benzofuro)[,2-b:2′,3′-e]pyridine (6) was synthesized using (Z)-2-(3-bromobenzylidene)benzofuran-3(2H)-one (20 g, 66.4 mmol) and by following the procedure described for the synthesis of 6-(4-bromophenyl)bis(benzo-furo)[3,2-b:2′,3′-e]pyridine (3)

[0201] Compounds of formula 1 may be prepared as described below.

General Procedure 1 for the Synthesis of the Compound of Formula (I)

[0202] ##STR00037##

[0203] A flask was flushed with nitrogen and charged with compound A (10.9 mmol), 4,4,5-tetramethyl-2-(3′,4′, 5′-triphenyl-[1,1′: 2′,1″-terphenyl]-3-yl)-1,3,2-dioxaborolane (7)(7.6 g, 13 mmol), Pd(PPh.sub.3).sub.4 (0.25 g, 0.22 mmol), and K.sub.2CO.sub.3 (3 g, 21.7 mmol). A mixture of deaerated THF/water (4:1, 75 mL) was added and the reaction mixture was heated to reflux under a nitrogen atmosphere for 24 h. Subsequently, additional 4,4,5,5-tetramethyl-2-(3′,4′,5′-triphenyl-[1,1′:2′,1″-terphenyl]-3-yl)-1,3,2-dioxaborolane (1.3 g, 2.2 mmol) and Pd(dppf)Cl.sub.2 (0.04 g, 0.05 mmol) were added and the mixture was refluxed for additional 8 h. After cooling down to room temperature, the reaction mixture was concentrated under reduced pressure and the formed precipitate was collected by suction filtration and washed with n-hexane. The obtained solid was dissolved in dichloromethane and the organic phase was washed with water three times. After drying over MgSO.sub.4, the organic phase was filtered through a pad of silica gel. After rinsing with additional dichloromethane, the filtrate was concentrated to a minimal amount and n-hexane was added. The formed precipitate was isolated by suction filtration and washed with n-hexane. Further purification was achieved by precipitation of the product from a concentrated dichloromethane solution by addition of cyclohexane. After stirring for 2 h, the resulting precipitate was isolated by suction filtration and washed with cyclohexane. After drying compound of formula (I) was obtained. Final purification was achieved by sublimation.

Synthesis of 6-(4′,5′, 6′-triphenyl-[1,1′: 2′,1″: 3″,1′″-quaterphenyl]-3′″-yl)bis(benzofuro)[3,2-b:2′,3′-e]pyridine (C1)

[0204] ##STR00038##

[0205] Compound C-1 was synthesized by following procedure 1. A flask was flushed with nitrogen and charged with 6-(3-bromophenyl)bis(benzo-furo)[3,2-b:2′,3′-e]pyridine (6) (4.5 g, 10.9 mmol), 4,4,5,5-tetramethyl-2-(3′,4′,5′-triphenyl-[1,1′:2′,1″-terphenyl]-3-yl)-1,3,2-dioxaborolane (7) (7.6 g, 13 mmol), Pd(PPh.sub.3).sub.4 (0.25 g, 0.22 mmol), and K.sub.2CO.sub.3 (3 g, 21.7 mmol). A mixture of deaerated THF/water (4:1, 75 mL) was added and the reaction mixture was heated to reflux under a nitrogen atmosphere for 24 h. Subsequently, additional 4,4,5,5-tetramethyl-2-(3′,4′,5′-triphenyl-[1,1′:2′,1″-terphenyl]-3-yl)-1,3,2-dioxaborolane (1.3 g, 2.2 mmol) and Pd(dppf)Cl2 (0.04 g, 0.05 mmol) were added and the mixture was refluxed for additional 8 h. After cooling down to room temperature, the reaction mixture was concentrated under reduced pressure and the formed precipitate was collected by suction filtration and washed with n-hexane. The obtained solid was dissolved in dichloromethane and the organic phase was washed with water three times. After drying over MgSO.sub.4, the organic phase was filtered through a pad of silica gel. After rinsing with additional dichloromethane, the filtrate was concentrated to a minimal amount and n-hexane was added. The formed precipitate was isolated by suction filtration and washed with n-hexane. Further purification was achieved by precipitation of the product from a concentrated dichloromethane solution by addition of cyclohexane. After stirring for 2 h, the resulting precipitate was isolated by suction filtration and washed with cyclohexane. After drying, 6.3 g of 6-(4′,5′,6′-triphenyl-[1,1′:2′,1″:3″,1′″-quaterphenyl]-3′″-yl)bis(benzofuro)[3,2-b:2′,3′-e]pyridine (C1) were obtained. Final purification was achieved by sublimation. HPLC/ESI-MS: m/z=792 ([M+H]+).

General Procedure 2 for the Synthesis of the Compound of Formula (I)

[0206] ##STR00039##

[0207] A flask was flushed with nitrogen and charged with compound B (12.8 mmol), 2-([1,1′-biphenyl]-2-yl)-4-chloro-6-phenyl-1,3,5-triazine (8) (4.6 g, 13.4 mmol), Pd(PPh.sub.3).sub.4 (0.3 g, 0.26 mmol), and K.sub.2CO.sub.2 (3.5 g, 25.6 mmol). A mixture of deaerated THF/water (4:1, 50 mL) was added and the reaction mixture was heated to reflux under a nitrogen atmosphere for 21 h. After cooling down to 5° C. using an ice bath, the formed precipitate was collected by suction filtration and washed with THF, water (until pH neutral) and methanol. The obtained solid was dissolved in hot chlorobenzene and filtered through a pad of silica gel. After rinsing with additional hot chlorobenzene, the filtrate was concentrated under reduced pressure and the resulting precipitate was collected by suction filtration and washed with a minimal amount of chlorobenzene. After drying, compound of formula (I) was obtained. Purification was achieved by sublimation.

Synthesis of 6-(4-(4-([1,1′-biphenyl]-2-yl)-6-phenyl-1,3,5-triazin-2-yl)phenyl)bis(benzofuro)[3,2-b:2′,3′-e]pyrldine (C-2)

[0208] ##STR00040##

[0209] Compound C.sub.2 was synthesized by following general procedure 2. A flask was flushed with nitrogen and charged with 6-(4-(4,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phen)i)bis(benzofuro)[3,2-b:2′,3′-e]pyridine (4) (5.9 g, 12.8 mmol), 2-([1,1′-biphenyl]-2-yl)-4-chloro-6-phenyl-1,3,5-triazine (8) (4.6 g, 13.4 mmol), Pd(PPh.sub.3).sub.4 (0.3 g, 0.26 mmol), and K.sub.2CO.sub.3 (3.5 g, 25.6 mmol). A mixture of deaerated THF/water (4:1, 50 mL) was added and the reaction mixture was heated to reflux under a nitrogen atmosphere for 21 h. After cooling down to 5° C. using an ice bath, the formed precipitate was collected by suction filtration and washed with THF, water (until pH neutral) and methanol. The obtained solid was dissolved in hot chlorobenzene and filtered through a pad of silica gel. After rinsing with additional hot chlorobenzene, the filtrate was concentrated under reduced pressure and the resulting precipitate was collected by suction filtration and washed with a minimal amount of chlorobenzene. After drying, 8 g of a 6-(4-(4-([1,1′-biphenyl]-2-yl)-6-phenyl-1,3,5-triazin-2-yl)phenyl)bis(benzofuro)[3,2-b:2′,3′-e]pyridine (C-2) were obtained. Purification was achieved by sublimation. m/z=643 ([M+H].sup.+).

Synthesis of 6-(3-(4-([1,1′-biphenyl]-2-yl)-6-phenyl-1,3,5-triazin-2-yl)phenyl)bis(benzofuro)[3,2-b:2′,3′-e]pyridine (C-3)

[0210] ##STR00041##

[0211] The general procedure 2 was followed to yield 4.8 g (93% yield) of 6-(3-(4-([1,1′-biphenyl]-2-yl)-6-phenyl-1,3,5-triazin-2-yl)phenyl)bis(benzofuro)[3,2-b:2′,3′-e]pyridine (C-3). Purification was achieved by sublimation. m/z=643 ([M+H].sup.+).

Synthesis of 3′-(bis(benzofuro)[3,2-b:2′,3′-e]pyridin-6-yl)-[1,1′-biphenyl]-4-carbonitrile (C-15)

[0212] ##STR00042##

[0213] The general procedure 2 was followed to yield 5.5 g (64% yield) of a 3′-(bis(benzofuro)[3,2-b:2′,3′-e]pyridin-6-yl)-[1,1′-biphenyl]-4-carbonitrile (C-15). Purification was achieved by sublimation. m/z=437 ([M+H].sup.+).

Synthesis of (4′-(bis(benzofuro)[3,2-b:2′,3′-e]pyridin-6-yl)-[1,1′-biphenyl]-3-yl)dimethylphosphine oxide (C-21)

[0214] ##STR00043##

[0215] The general procedure 2 was followed to yield 5.5 g (82% yield) of a (4′-(bis(benzofuro)[3,2-b:2′,3′-e]pyridin-6-yl)-[1,1′-biphenyl]-3-yl)dimethylphosphine oxide (C-21) were obtained. Purification was achieved by sublimation. m/z=488 ([M+H].sup.+).

Synthesis of (3′-(bis(benzofuro)[3,2-b:2′,3′-e]pyridin-6-yl)-[1,1′-biphenyl]-4-yl)dimethylphosphine oxide (C-24)

[0216] ##STR00044##

[0217] The general procedure 2 was followed to yield 4.1 g (77% yield) of a (4′-(bis(benzofuro)[3,2-b:2′,3′-e]pyridin-6-yl)-[1,1′-biphenyl]-3-yl)dimethylphosphine oxide (C-24) were obtained. Purification was achieved by sublimation. m/z=488 ([M+H].sup.+).

[0218] Melting Point

[0219] The melting point (mp) is determined as peak temperatures from the DSC curves of the above TGA-DSC measurement or from separate DSC measurements (Mettler Toledo DSC822e, heating of samples from room temperature to completeness of melting with heating rate 10 K/min under a stream of pure nitrogen. Sample amounts of 4 to 6 mg are placed in a 40 μL Mettler Toledo aluminum pan with lid, a <1 mm hole is pierced into the lid).

[0220] Glass Transition Temperature

[0221] The glass transition temperature (Tg) is measured under nitrogen and using a heating rate of 10 K per min in a Mettler Toledo DSC 822e differential scanning calorimeter as described in DIN EN ISO 31357, published in March 2010.

[0222] Reduction Potential

[0223] The reduction potential is determined by cyclic voltammetry with poteniostatic device Metrohm PGSTAT30 and software Metrohm Autolab GPES at room temperature. The redox potentials given at particular compounds were measured in an argon de-aerated, dry 0.1M THF solution of the tested substance, under argon atmosphere, with 0.1M tetrabutylammonium hexafluorophosphate supporting electrolyte, between platinum working electrodes and with an Ag/AgCl pseudo-standard electrode (Metrohm Silver rod electrode), consisting of a silver wire covered by silver chloride and immersed directly in the measured solution, with the scan rate 100 mV/s. The first run was done in the broadest range of the potential set on the working electrodes, and the range was then adjusted within subsequent runs appropriately. The final three runs were done with the addition of ferrocene (in 0.1M concentration) as the standard. The average of potentials corresponding to cathodic and anodic peak of the studied compound, after subtraction of the average of cathodic and anodic potentials observed for the standard Fe/Fe redox couple, afforded finally the values reported above. All studied compounds as well as the reported comparative compounds showed well-defined reversible electrochemical behaviour.

[0224] Dipole Moment

[0225] The dipole moment |{right arrow over (μ)}| of a molecule containing N atoms is given by:

[00001]$\stackrel{.fwdarw.}{\mu }=\underset{i}{\overset{N}{.Math.}}{q}_i\stackrel{.fwdarw.}{r_i}$$.Math.\stackrel{.fwdarw.}{\mu }.Math.=\sqrt{{\mu }_x^2+{\mu }_y^2+{\mu }_z^2}$

where q.sub.i and {right arrow over (r)}.sub..Math. are the partial charge and position of atom i in the molecule.

[0226] The dipole moment is determined by a semi-empirical molecular orbital method.

[0227] The geometries of the molecular structures are optimized using the hybrid functional B3LYP with the 6-31G* basis set in the gas phase as implemented in the program package TURBOMOLE V6.5. If more than one conformation is viable, the conformation with the lowest total energy is selected to determine the bond lengths of the molecules.

[0228] Calculated HOMO and LUMO

[0229] The HOMO and LUMO are calculated with the program package TURBOMOLE V6.5. The optimized geometries and the HOMO and LUMO energy levels of the molecular structures are determined by applying the hybrid functional B3LYP with a 6-31G* basis set in the gas phase. If more than one conformation is viable, the conformation with the lowest total energy is selected.

[0230] General Procedure 1 for Fabrication of OLEDs

[0231] For top emission devices, for Example 1 and comparative example in table 2, a glass substrate was cut to a size of 50 mm×50 mm×0.7 mm, ultrasonically cleaned with isopropyl alcohol for 5 minutes and then with pure water for 5 minutes, and cleaned again with UV ozone for 30 minutes. 100 nm Ag were deposited on the glass substrate at a pressure of 10-5 to 10-7 mbar to form the anode.

[0232] Then, 92 vol.-% Biphenyl-4-yl(9,9-diphenyl-9H-fluoren-2-yl)-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-amine (CAS 1242056-42-3) with 8 vol.-% 2,2′,2″-(cyclopropane-1,2,3-triylidene)tris(2-(p-cyanotetrafluorophenyl)acetonitrile) was vacuum deposited on the anode, to form a HIL having a thickness of 0 nm. Then, Biphenyl-4-yl(9,9-diphenyl-9H-fluoren-2-yl)-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-amine was vacuum deposited on the HIL, to form a HTL having a thickness of 118 nm.

[0233] Then, N,N-bis(4-(dibenzo[b,d]furan-4-yl)phenyl)-[1,1′:4′,1″-terphenyl]-4-amine (CAS 1198399-61-9) was vacuum deposited on the HTL, to form an electron blocking layer (EBL) having a thickness of 5 nm.

[0234] Then, 97 vol-% Hog (Sun Fine Chemicals) as EML host and 3 vol-% BD200 (Sun Fine Chemicals) as fluorescent blue dopant were deposited on the EBL, to form a blue-emitting EML with a thickness of 20 nm.

[0235] Then the auxiliary ETL was formed with a thickness of 5 nm by depositing compound C-2 according to the inventive example 1 and by depositing compound 1 according to the comparative example 1 on the emission layer (EML).

[0236] Then, the electron transporting layer was formed on the auxiliary electron transport layer by depositing 2-([1,1′-biphenyl]-4-yl)-4-(9,9-diphenyl-9H-fluoren-4-yl)-6-phenyl-1,3,5-triazine (ETM-1) with a thickness of 31 nm. The electron transport layer comprises 50 wt.-% matrix compound and 50 wt.-% of LiQ, see Table 2.

[0237] Then, the electron injection layer was formed on the electron transporting layer by deposing Yb with a thickness of 2 nm.

[0238] Ag was evaporated at a rate of 0.01 to 1 Å/s at 10-7 mbar to form a cathode with a thickness of 11 nm.

[0239] A cap layer of Biphenyl-4-yl(9,9-diphenyl-9H-fluoren-2-yl)-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-amine was formed on the cathode with a thickness of 75 nm.

[0240] The OLED stack is protected from ambient conditions by encapsulation of the device with a glass slide. Thereby, a cavity is formed, which includes a getter material for further protection.

[0241] General Procedure 2 for Fabrication of OLEDs

[0242] For top emission devices, for Example 2 table 3, a glass substrate was cut to a size of 50 mm×50 mm×0.7 mm, ultrasonically cleaned with isopropyl alcohol for 5 minutes and then with pure water for 5 minutes, and cleaned again with UV ozone for 30 minutes. 100 nm Ag were deposited on the glass substrate at a pressure of 10-5 to 10-7 mbar to form the anode.

[0243] Then, 92 vol.-% Biphenyl-4-yl(9,9-diphenyl-9H-fluoren-2-yl)-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-amine (CAS 1242056-42-3) with 8 vol.-% 2,2′,2″-(cyclopropane-1,2,3-triylidene)tris(2-(p-cyanotetrafluorophenyl)acetonitrile) was vacuum deposited on the anode, to form a HIL having a thickness of 10 nm. Then, Biphenyl-4-yl(9,9-diphenyl-9H-Bren-2-yl)-[4-(9-phenyl-H-carbazol-3-yl)phenyl]-amine was vacuum deposited on the HIL, to form a HTL having a thickness of 118 nm.

[0244] Then, N,N-bis(4-(dibenzo[b,d]furan-4-yl)phenyl)[1,1′:4′,1″-terphenyl]-4-amine (CAS 1198399-61-9) was vacuum deposited on the HTL, to form an electron blocking layer (EBL) having a thickness of 5 nm.

[0245] Then, 97 vol.-% Hog (Sun Fine Chemicals) as EML host and 3 vol.-% BD200 (Sun Fine Chemicals) as fluorescent blue dopant were deposited on the EBL, to form a blue-emitting EML with a thickness of 20 nm.

[0246] Then the auxiliary ETL was formed with a thickness of 5 nm by depositing compound 1 on the emission layer (EML).

[0247] Then, the electron transporting layer was formed on the auxiliary electron transport layer by depositing compound C-2 with a thickness of 31 nm. The electron transport layer comprises 50 wt.-% matrix compound and 50 wt.-% of LiQ, see Table 3.

[0248] Then, the electron injection layer was formed on the electron transporting layer by deposing Yb with a thickness of 2 nm.

[0249] Ag was evaporated at a rate of 0.01 to 1 Å/s at 10-7 mbar to form a cathode with a thickness of 11 nm.

[0250] A cap layer of Biphenyl-4-yl(9,9-diphenyl-9H-fluoren-2-yl)-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-amine was formed on the cathode with a thickness of 75 nm.

[0251] The OLED stack is protected from ambient conditions by encapsulation of the device with a glass slide. Thereby, a cavity is formed, which includes a getter material for further protection.

[0252] To assess the performance of the inventive examples compared to the prior art, the current efficiency is measured at 20° C. The current-voltage characteristic is determined using a Keithley 2635 source measure unit, by sourcing a voltage in V and measuring the current in mA flowing through the device under test. The voltage applied to the device is varied in steps of 0.1V in the range between 0V and 10V. Likewise, the luminance-voltage characteristics and CIE coordinates are determined by measuring the luminance in cd/m.sup.2 using an Instrument Systems CAS-140CT array spectrometer for each of the voltage values. The cd/A efficiency at 10 mA/cm2 is determined by interpolating the luminance-voltage and current-voltage characteristics, respectively.

[0253] Lifetime LT of the device is measured at ambient conditions (20° C.) and 30 mA/cm.sup.2, using a Keithley 2400 source meter, and recorded in hours.

[0254] The brightness of the device is measured using a calibrated photo diode. The lifetime LT is defined as the time till the brightness of the device is reduced to 97% of its initial value.

[0255] The light output in external efficiency EQE and power efficiency (lm/W efficiency) are determined at 10 mA/cm2 for top emission devices.

[0256] To determine the efficiency EQE in % the light output of the device is measured using a calibrated photodiode.

[0257] To determine the power efficiency in lm/W, in a first step the luminance in candela per square meter (cd/m2) is measured with an array spectrometer CAS140 Cr from Instrument Systems which has been calibrated by Deutsche Akkreditierungs¬stelle (DAkkS). In a second step, the luminance is then multiplied by a and divided by the voltage and current density.

Technical Effect of the Invention

[0258] The compounds according to formula (I) and the organic electronic devices comprising an organic semiconducting layer comprising or made of a compound of formula (I) solve the problem underlying the present invention by being superior over the organic electroluminescent devices and compounds known in the art, in particular to improve the lifetime (LT97, 30 mA/cm.sup.2) of the respective device.

[0259] The beneficial effect of the invention on the performance of organic electronic devices can be seen in Table 2 and Table 3. As can be seen in Table 2, the performance of the organic electronic devices of the inventive examples 1 with respect to lifetime (LT97, 30 mA/cm.sup.2) is improved as compare to the comparative example 1.

TABLE-US-00001 TABLE 1 Properties of comparative example 1 and compound of formula (I) Diplole mp Tg T.sub.RO HOMO LUMO moment Referred to as: Structure (° C.) (° C.) (° C.) (eV) (eV) (Debye) Comparative example 1 Compound 1 [00045] — 141 267 −5.72 −1.82 0.30 Example 1 C1 [00046] 289 159 256 −5.82 −1.63 1.61 Example 2 C2 [00047] 331 129 266 −6.01 −2.08 0.73 C-3 [00048] 322 117 259 −5.87 −1.87 0.93 C-15 [00049] 305 94 208 −6.01 −1.89 5.04 C-21 [00050] 294 115 226 −5.84 −2.76 4.42 C-24 [00051] 302 118 234 −5.95 −1.78 3.68

TABLE-US-00002 TABLE 2 Performance of an organic electroluminescent device comprising an electron transport layer 1 comprising a compound of formula (I) Compound Concentration Concentration Thickness Operating cd/A in of matrix of alkali electron voltage efficiency LT97 at electron Thickness compound in Alkali organic transport at 10 at 10 30 transport ETL-1 Matrix ETL-2 organic complex layer 2 mA/cm.sup.2 mA/cm.sup.2 mA/cm.sup.2 layer 1 (nm) compound (vol.-%) complex (vol.-%) (nm) (V) (cd/A) (h) Comparative Compound 5 ETM-1 50 LiQ 50 31 3.5 8.4 42 example 1 1- Example 1 C-1 5 ETM-1 50 LiQ 50 31 3.7 7.6 61 The features disclosed in the foregoing description and in the dependent claims may, both separately and in any combination thereof, be material for realizing the aspects of the disclosure made in the independent claims, in diverse forms thereof.

TABLE-US-00003 TABLE 3 Performance of an organic electroluminescent device comprising an electron transport layer-2 comprising a compound of formula 1 Concentration Concentration Operating cd/A of matrix of alkali voltage efficiency LT97 at compound in Alkali organic Thickness at 10 at 10 30 Matrix ETL 2 organic complex ETL-2 mA/cm.sup.2 mA/cm.sup.2 mA/cm.sup.2 compound (vol.-%) complex (vol.-%) (nm) (V) (cd/A) (h) Example 2 C-2  50 LiQ 50 31 3.7 6.05  96 Example 3 C-3  50 LiQ 50 31 3.6 7.6  100 Example 4 C-15 50 LiQ 50 31 3.6 7.2   65 The features disclosed in the foregoing description and in the dependent claims may, both separately and in any combination thereof, be material for realizing the aspects of the disclosure made in the independent claims, in diverse forms thereof.

[0260] The features disclosed in the foregoing description and in the dependent claims may, both separately and in any combination thereof, be material for realizing the aspects of the disclosure made in the independent claims, in diverse forms thereof.