SEE ADDENDUM

Abstract

The present invention relates to a compound having the formula (I), an organic semiconducting layer comprising the same, an organic electronic device comprising the same, a display device comprising the same and a lighting device comprising the same.

##STR00001##

Claims

1. Compound of Formula (I) ##STR00043## wherein one or two of R.sup.1 to R.sup.11 are independently a group G, wherein G is selected from the group consisting of substituted or unsubstituted C.sub.6 to C.sub.48 aryl, substituted or unsubstituted C.sub.2 to C.sub.42 heteroaryl, and substituted or unsubstituted alkenyl, substituted or unsubstituted C.sub.1 to C.sub.16 alkyl, substituted or unsubstituted C.sub.1 to C.sub.16 alkoxy, CN, F, deuterium, nitrile, amino, P(═Y)(R.sup.12).sub.2 with Y being O or S, wherein R.sup.12 are independently selected from the group consisting of C.sub.1 to C.sub.16 alkyl, C.sub.1 to C.sub.16 alkoxy, C.sub.6 to C.sub.18 aryl and C.sub.3 to C.sub.25 heteroaryl; the remaining R.sup.1 to R.sup.11 which are not G are H; the one or two G may be attached to the benzoacridine moiety in Formula (I) via a direct bond or via a spacer unit; the one or two spacer unit(s), if present, is/are independently selected from the group consisting of substituted or unsubstituted C.sub.6 to C.sub.18 arylene and substituted or unsubstituted C.sub.2 to C.sub.20 heteroarylene; the one or more substituent(s) of R.sup.1 to R.sup.11 and/or the spacer unit(s), if present, are independently selected from the group consisting of C.sub.6 to C.sub.18 aryl, wherein it may be provided that adjacent C.sub.6 to C.sub.18 aryl substituents are linked with each other via a direct bond, C.sub.3 to C.sub.20 heteroaryl, C.sub.1 to C.sub.16 alkyl, D, F, C.sub.1 to C.sub.16 alkoxy, CN, CN-substituted C.sub.6 to C.sub.18 aryl, and P(═Y)(R.sup.12).sub.2 with Y being O or S, wherein R.sup.12 is independently selected from the group consisting of C.sub.1 to C.sub.16 alkyl, C.sub.1 to C.sub.16 alkoxy, C.sub.6 to C.sub.18 aryl and C.sub.3 to C.sub.25 heteroaryl; and it is provided that if one of R.sup.9 and R.sup.11 is G, then the other one of R.sup.9 and R.sup.11 is H.

2. Compound according to claim 1, wherein in case that R.sup.11 is G one of R.sup.1 to R.sup.10 is also G, wherein the two G are selected independently from each other.

3. Compound according to claim 1, wherein in case that R.sup.11 is G substituents on this group G are independently selected form the group consisting of D, F, CN, nitrile, amino C.sub.6 to C.sub.18 aryl, CN-substituted C.sub.6 to C.sub.18 aryl, C.sub.3 to C.sub.20 heteroaryl, CN, C.sub.1 to C.sub.16 alkyl, substituted or unsubstituted alkenyl, and substituted or unsubstituted C.sub.1 to C.sub.16 alkoxy.

4. Compound according to claim 1, wherein one or two of R.sup.2, R.sup.4, R.sup.5, R.sup.7, R.sup.8, and R.sup.11 are G.

5. Compound according to claim 1, wherein in case that two of R.sup.1 to R.sup.11 are G and R.sup.5 is G, then one of R.sup.8, R.sup.9 or R.sup.11 is the other G.

6. Compound according to claim 1, wherein the spacer unit is independently a C.sub.6 to C.sub.12 aryl.

7. Compound according to claim 1, wherein G is independently selected from substituted or unsubstituted C.sub.6 to C.sub.18 aryl, substituted or unsubstituted C.sub.3 to C.sub.21 heteroaryl, or substituted alkenyl.

8. Compound according to claim 1, wherein in case that G is heteroaryl, the heteroaryl is a N-containing heteroaryl.

9. Compound according to claim 1, wherein the one or two groups G is/are independently selected from the group consisting of phenyl, naphthyl, anthracenyl, phenanthryl, fluorenyl, spirobi[fluorenyl], fluoranthenyl, pyridinyl, bi-pyridinyl, pyrimidinyl, diazinyl, triazinyl, quinolinyl, quinazolinyl, benzimidazolyl, benzoacridinyl, dibenzoacridinyl, benzo [h] quinazolinyl, carbazolyl, carbolinyl, 4,5-diazacabazolyl, phenanthrolinyl, dibenzofuranyl, dimethylphosphineoxide, diphenylphosphineoxide, triphenylalkenyl, [1]benzotieno[3,2-d]pyrimidinyl, ##STR00044## wherein the respective groups may be substituted or unsubstituted.

10. Compound according to claim 1, wherein the one or more substituent(s), if present on one or more or the groups R.sup.1 to R.sup.11 and/or the spacer unit(s), are independently selected from the group consisting of C.sub.6 to C.sub.12 aryl, C.sub.5 to C.sub.12 heteroaryl, CN-substituted C.sub.6 to C.sub.12 aryl, C.sub.6 to C.sub.12 aryl substituted with P(═O)(R.sup.12).sub.2 with R.sup.12 being C.sub.1 to C.sub.12 alkyl or phenyl, C.sub.1 to C.sub.5 alkyl, CN, P(═O)(R.sup.12).sub.2 with R.sup.12 being C.sub.1 to C.sub.5 alkyl or phenyl.

11. Compound according to claim 1, wherein the number of aromatic rings in the compound of Formula (I) is from 5 to 15.

12. Organic semiconducting layer comprising the compound of Formula (I) according to claim 1.

13. Organic electronic device comprising the organic semiconducting layer according to claim 12.

14. Display device comprising the organic electronic device according to claim 13.

15. Lighting device comprising the organic electronic device according to claim claim 13.

16. Compound according to claim 10, wherein the one or more substituent(s), if present on one or more or the groups R.sup.1 to R.sup.11 and/or the spacer unit(s), are independently selected from the group consisting of phenyl, naphthyl, biphenyl, CN-substituted phenyl, pyridyl, CN, dibenzofuranyl, dimethylphosphineoxide-substituted phenyl, ethyl, methyl, dimethylphosphine oxide or diphenylphosphine oxide.

17. Compound according to claim 11, wherein the number of aromatic rings in the compound of Formula (I) is from 6 to 10.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0190] 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:

[0191] FIG. 1 is a schematic sectional view of an organic light-emitting diode (OLED), according to an exemplary embodiment of the present invention;

[0192] FIG. 2 is a schematic sectional view of an OLED, according to an exemplary embodiment of the present invention.

[0193] 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

[0194] 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.

[0195] 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.

[0196] 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.

[0197] Instead of a single electron transport layer 160, optionally an election transport layer stack (ETL) can be used.

[0198] 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) 145 and a hole blocking layer (HBL) 155.

[0199] 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.

[0200] Preferably, the organic semiconducting layer comprising a compound of Formula (I) may be an HBL.

[0201] 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).

[0202] Referring to FIG. 3, the OLED 200 includes a substrate 110, 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.

[0203] Preferably, the organic semiconducting layer comprising a compound of Formula (I) may be the first ETL, n-type CGL and/or second ETL.

[0204] 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.

[0205] 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.

[0206] Experimental Data

[0207] Melting Point

[0208] 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).

[0209] Glass Transition Temperature

[0210] 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 11357, published in March 2010.

[0211] Rate Onset Temperature

[0212] The rate onset temperature (T.sub.RO) is determined by loading 100 mg compound into a VTE source. As VTE source a point source for organic materials may be used as supplied by Kurt J. Lesker Company (www.lesker.com) or CreaPhys GmbH (http://www.creaphys.com). The VTE source is heated at a constant rate of 15 K/min at a pressure of less than 10.sup.−5 mbar and the temperature inside the source measured with a thermocouple. Evaporation of the compound is detected with a QCM detector which detects deposition of the compound on the quartz crystal of the detector. The deposition rate on the quartz crystal is measured in Angstrom per second. To determine the rate onset temperature, the deposition rate is plotted against the VTE source temperature. The rate onset is the temperature at which noticeable deposition on the QCM detector occurs. For accurate results, the VTE source is heated and cooled three time and only results from the second and third run are used to determine the rate onset temperature.

[0213] To achieve good control over the evaporation rate of an organic compound, the rate onset temperature may be in the range of 200 to 255° C. If the rate onset temperature is below 200° C. the evaporation may be too rapid and therefore difficult to control. If the rate onset temperature is above 255° C. the evaporation rate may be too low which may result in low tact time and decomposition of the organic compound in VTE source may occur due to prolonged exposure to elevated temperatures.

[0214] The rate onset temperature is an indirect measure of the volatility of a compound. The higher the rate onset temperature the lower is the volatility of a compound.

[0215] Reduction Potential

[0216] The reduction potential is determined by cyclic voltammetry with potenioststic 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 Fc.sup.+/Fc redox couple, afforded finally the values reported above. All studied compounds as well as the reported comparative compounds showed well-defined reversible electrochemical behaviour.

[0217] Dipole Moment

[0218] 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}}_{\mathrm{.Math.}}$$.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.l are the partial charge and position of atom i in the molecule.

[0219] The dipole moment is determined by a semi-empirical molecular orbital method.

[0220] 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 (TURBOMOLE GmbH, Litzenhardtstrasse 19, 76135 Karlsruhe, Germany). If more than one conformation is viable, the conformation with the lowest total energy is selected to determine the bond lengths of the molecules.

[0221] Calculated HOMO and LUMO

[0222] The HOMO and LUMO are calculated with the program package TURBOMOLE V6.5 (TURBOMOLE GmbH, Litzenhardtstrasse 19, 76135 Karlsruhe, Germany). 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.

[0223] Synthesis Procedures

[0224] Molecules Synthesized

##STR00026## ##STR00027## ##STR00028##

6-chlorobenzo[a]acridine

[0225] ##STR00029##

[0226] 5,6-dihydrobenzo[a]acridine (10.4 g, 45.0 mmol) and 1-chloropyrrolidine-2,5-dione (11.6 g, 90.0 mmol) were placed in a flask under nitrogen atmosphere and dissolved in acetonitrile (230 mL) at room temperature. The solution was heated to 80° C. and stirred for 5 h. After cooling down to room temperature, the resulting precipitate was isolated by suction filtration and washed with acetonitrile. The solid was dissolved in chloroform (250 mL) and washed first with Na.sub.2CO.sub.3 (aq.) (50 mL) and then with water. Organic phase was dried over Na.sub.2SO.sub.4, drying agent was filtered off and solvents were completely removed under pressure. Product was recrystallized in cyclohexane and dried under vacuum to afford 4.7 g (40%) of a solid. GC-MS>99%.

6-(3-(9-phenyl-9H-fluoren-9-yl)phenyl)benzo[a]acridine (Compound A-1)

[0227] ##STR00030##

[0228] A flask was flushed with nitrogen and charged with 6-chlorobenzo[a]acridine (2.1 g, 8.0 mmol), 4,4,5,5-tetramethyl-2-(3-(9-phenyl-9H-fluoren-9-yl)phenyl)-1,3,2-dioxaborolane (4.3 g, 9.6 mmol), chloro(crotyl)(2-dicydohexylphosphino-2′,6′-dimethoxybiphenyl)palladium(II) (97 mg, 0.16 mmol), potassium phosphate (3.4 g, 16.0 mmol). A mixture of deaerated tetrahydrofurane/water (4:1, 80 mL) was added and the reaction mixture was heated to 50° C. under a nitrogen atmosphere overnight. After cooling down to room temperature, the resulting precipitate was isolated by suction filtration and washed with water. The crude product was then dissolved in hot chloroform (300 mL) and filtered through a silicagel pad. After rinsing with additional hot chloroform (600 mL) and hot chlorobenzene (600 mL), the filtrate was concentrated under reduced pressure to a minimal volume and n-hexane (200 mL) was added. The resulting suspension was stirred at room temperature and the precipitate was collected by suction filtration. The compound was finally recrystallized in acetonitrile/tetrahydrofurane (40/60 mL) to yield 3.0 g (70%) of a solid after drying. Final purification was achieved by sublimation. m/z=546 ([M+H].sup.+), 568 ([M+Na].sup.+).

##STR00031##

Benzo[a]acridin-5-yl trifluoromethanesulfonate

[0229] ##STR00032##

[0230] Benzo[a]acridin-5-ol (6.5 g, 26.5 mmol) was suspended in anhydrous dichloromethane (240 mL) in a flask equipped with a drying tube filled with calcium chloride. Pyridine (4.2 mL, 53.0 mmol) was added and the mixture was cooled down to 0° C. Trifluoromethanesulfonic anhydride (5.3 mL, 31.8 mmol) was added dropwise and the solution was stirred overnight. Solution was again cooled down to 0° C. Pyridine (1.0 mL, 13.3 mmol) and trifluoromethanesulfonic anhydride (1.3 mL, 8.0 mmol) were added and the solution was stirred overnight. Crude reaction was washed with water, dried over Na.sub.2SO.sub.4, and purified by column chromatography using dichloromethane as eluent. Organic solvents from the column were partially removed under reduced pressure and n-hexane was added to induce precipitation. The precipitate was collected by suction filtration to yield 4.0 g (40%) of a solid after drying.

5-(3-(9-Phenyl-9H-fluoren-9-yl)phenyl)benzo[a]acridine (Compound A-2)

[0231] ##STR00033##

[0232] A flask was flushed with nitrogen and charged with benzo[a]acridin-5-yl trifluoromethanesulfonate (3.9 g, 10.3 mmol), 4,4,5,5-tetramethyl-2-(3-(9-phenyl-9H-fluoren-9-yl)phenyl)-1,3,2-dioxaborolane (5.1 g, 11.4 mmol), tetrakis(triphenylphosphin)palladium(o) (239 mg, 0.21 mmol), potassium carbonate (2.9 g, 20.7 mmol). A mixture of deaerated tetrahydrofurane/water (4:1, 50 mL) was added and the reaction mixture was heated to reflux under a nitrogen atmosphere overnight. After cooling down to room temperature, the solvents were partially removed under reduced pressure and dichloromethane first and then hexane were added. The resulting precipitate was isolated by suction filtration and washed with water. The crude product was then dissolved in hot chlorobenzene (200 mL) and filtered through a silicagel pad. After rinsing with additional hot chlorobenzene (450 mL) and tetrahydrofurane (50 mL), the solvents were completely removed under reduced pressure. The crude product was dissolved in hot tetrahydrofurane and acetonitrile (50 mL) was added to induce the precipitation. The precipitate was collected by suction filtration. The recrystallization step was repeated one more time to yield 4.4 g (79%) of a solid after drying. Final purification was achieved by sublimation. m/z=546 ([M+H].sup.+).

5-(4-(4,6-Diphenyl-1,3,5-triazin-2-yl)phenyl)benzo[a]acridine (Compound A-3)

[0233] ##STR00034##

[0234] A flask was flushed with nitrogen and charged with benzo[a]acridin-5-yl trifluoromethanesulfonate (10.0 g, 26.5 mmol), 2,4-diphenyl-6-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-1,3,5-triazine (12.7 g, 29.2 mmol), tetrakis(triphenylphosphin)palladium(o) (612 mg, 0.53 mmol), and potassium carbonate (7.32 g, 53 mmol). A mixture of deaerated tetrahydrofurane/water (5:1, 150 mL) was added and the reaction mixture was heated to 75° C. under a nitrogen atmosphere overnight. After cooling down to 5° C., the resulting precipitate was isolated by suction filtration and washed with tetrahydrofurane (3×10 mL), n-hexane (3×20 mL), water (1.3 L) and methanol (2×30 mL). The crude product was further purified by column chromatography (silicagel, chlorobenzene to chlorobenzene/ethanol 96/4). The filtrate was concentrated under reduced pressure to a volume of 200 mL and stirred at room temperature over 2 hours. The resulting precipitate was collected by suction filtration and washed with chlorobenzene to yield 10.8 g (76%) of a bright yellow solid after drying. Final purification was achieved by sublimation. m/z=537.1 ([M+H].sup.+).

1,4-Bis(benzo[a]acridin-5-yl)benzene (Compound A-5)

[0235] ##STR00035##

[0236] A solution of benzo[a]acridin-5-yl trifluoromethanesulfonate (12 g, 31.8 mmol), 1,4-phenylenediboronic acid (2.64 g, 15.9 mmol) and potassium carbonate (8.79 g, 63.6 mmol) in THF/water (5:1, 225 mL) was degassed with nitrogen over 45 minutes. Tetrakis(triphenylphosphin)palladium(o) (730 mg, 0.64 mmol) was added and the reaction mixture was heated to 75° C. under nitrogen atmosphere overnight. After cooling down, the resulting precipitate was isolated by suction filtration and washed with water and methanol. The crude product was further purified by soxhlet extraction in chlorobenzene to yield 4.9 g (58%) of a grey greenish solid after drying. Final purification was achieved by sublimation. m/z=533.1 ([M+H].sup.+).

4-(benzo[a]acridin-5-yl-[1,1′:4′,1″-terphenyl]-4-carbonitrile (Compound A-4)

[0237] ##STR00036##

[0238] A solution of potassium carbonate (5.8 g, 42.0 mmol) in water (30 mL) and a solution of 4″-(44,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-[1,1′:4′,1″-terphenyl]-4-carbonitrile (8.0 g, 21 mmol) and benzo[a]acridin-5-yl trifluoromethanesulfonate (7.92 g, 21 mmol) in tetrahydrofurane (120 mL) were degassed with nitrogen over 30 minutes. After the two solutions were combined, tetrakis(triphenylphosphin)palladium(o) (485 mg, 0.42 mmol) was added and the reaction mixture was heated to 70° C. under a nitrogen atmosphere overnight. After cooling down to 5° C., the resulting precipitate was isolated by suction filtration and washed with tetrahydrofurane, water and methanol. The crude product was then dissolved in chloroform and filtered through a pad of silica gel. After rinsing with additional hot chloroform (1 L) and (chloroform/ethyl acetate—10/1) (600 mL), the filtrate was concentrated under reduced pressure to a volume of 50 mL and n-hexane was added. The resulting precipitate was collected by suction filtration and washed with n-hexane. The crude product was further purified by recrystallization from chlorobenzene to yield 8.3 g (82%) of a bright yellow solid after drying. Final purification was achieved by sublimation. m/z=483.1 ([M+H].sup.+).

[0239] General Procedure for Fabrication of OLEDs

[0240] For the top emission OLED devices of example-1 and of the comparative example a substrate with dimensions of 150 mm×150 mm×0.7 mm was ultrasonically cleaned with a 2% aquatic solution of Deconex FPD 211 for 7 minutes and then with pure water for 5 minutes, and dried for 15 minutes in a spin rinse dryer. Subsequently, Ag was deposited as anode at a pressure of 10-5 to 10-7 mbar.

[0241] Then, HT-1 and D-1 were vacuum co-deposited on the anode to form a HIL. Then, HT-1 was vacuum deposited on the HIL, to form an HTL. Then, HT-2 was vacuum deposited on the HTL to form an electron blocking layer (EBL).

[0242] Afterwards the emission layer was formed on the EBL by co-deposition of HOST-1 and EMITTER-1.

[0243] Then, the ET-1 was vacuum deposited onto the emission layer to form the hole blocking layer (HBL). Then, the electron transport layer was formed on the hole blocking layer by co-depositing a compound of formula (I) and LiQ for example-1. For the comparative example the electron transport layer was formed on the hole blocking layer by co-depositing the compound comparative-1 and LiQ.

[0244] Then, the electron injection layer is formed on the electron transporting layer by depositing Yb.

[0245] Ag:Mg is then evaporated at a rate of 0.01 to 1 Å/s at 10-7 mbar to form a cathode.

[0246] A cap layer of HT-1 is formed on the cathode.

[0247] The details of the layer stack in the top emission OLED devices are given below. A slash “/” separates individual layers. Layer thicknesses are given in squared brackets [. . . ], mixing ratios in wt % given in round brackets ( . . . ):

[0248] Layer Stack Details:

[0249] Ag [100 nm]/HT-1:D-1 (92:8) [10 nm]/HT-1 [118 nm]/HT-2 [5 nm]/H09:BD200 (97:3) [20 nm]/ET-1 [5 nm]/Compound of formula (I): LiQ (1:1) [31 nm]/Yb [2 nm]/Ag:Mg (90:10) [13 nm]/HT-1 [70 nm]

Technical Effect of the Invention

[0250] The OLED devices according to the invention show improved efficiency and lifetime at comparable voltage when using the compounds of formula (I) in an electron transport layer instead of the comparative compound.

List of Compounds Used

[0251]

TABLE-US-00001 IUPAC name Reference HT -1 N-([1,1'-biphenyl]-4yl)-9,9-e l-N-(4-(9-phenyl-9 US2016322581 carbazol-3-yl)pheny1)-9H-fluoren-2-amine [CAS 1242056-42-3] HT-2 N,N-bis(4-(dibenzo[b,d]furan-4-yl)pheny1)-[1,1′:4′,1″- JP2014096418 terphenyl]-4-amine [CAS 1198399-61-9] D-1 4,4′,4″-((1E,1′E,1″)-cyclopropane-1,2,3- US2008265216 triylidenetris(cyanomethanylylidene))tris(2,3,5,6- tetrafluorobenzonitrile) HOST-1 Ho9 (Fluorecent-blue host material) Commerically available from Sun Fine Chemicals, Inc., S. Korea EMITTER-1 BD2000 (Fluorecent-blue emitter material) Commerically available from Sun Fine Chemicals, Inc., S. Korea ET-1 2,4-diphenyl-6-(4′,5′,6′-triphenyl-[1,1′:2′,1″:3″,1′′′:3′′′,1′′′′- WO2016171358 quinquephenyl]-3′′′′-yl)-1,3,5-triazine [CAS 2032364-64-8] Comparative-1 7(4-(4-([1,1′-biphenyl]-3-yl)-6-phenyl-1,3,5-triazin-2- − yl)phenyl)dibenzo[c,h]acridine LiQ 8-Hydroxyquinolinolato-lithium WO2013079217 [CAS 850918-68-2]

TABLE-US-00002 TABLE 1 Properties of compounds A-1 to A-5 of formula (I) and of comparative compound Comparative-1. mp Tg T.sub.RO [° C.] [° C.] [° C.] Compara- tive-1 [00037] 317 148 286 A-1 [00038] 290 128 219 A-2 [00039] 261 126 202 A-3 [00040] 319 124 248 A-4 [00041] 288 104 237 A-5 [00042] 468 — 315

TABLE-US-00003 TABLE 2 Dipole moment, HOMO and LUMO levels of comparative-1 and compounds A1 to A5, simulated by DFT (B3LYP_Gaussian/6-31G*, gas phase) Dipole Moment HOMO LUMO [Debye] [eV] [eV] Comparative-1 1.77 −5.66 −2.00 A-1 1.86 −5.54 −1.85 A-2 1.67 −5.62 −1.87 A-3 1,88 −5.71 −2.06 A-4 6.69 −5.73 −2.02 A-5 1.79 −5.62 −1.96

TABLE-US-00004 TABLE 3 Performance of organic electrolumineseent device comprising the compounds of formula (1) as a matrix compound in the electron transport layer. CIE 1931 y = 0.045 Operating voltage at 10 CEff at LT97 at OLED device Matrix mA/cm.sup.2 10 mA/cm.sup.2 30 mA/cm.sup.2 examples compound n-additive (V) (cd/A) (hours) Comparative Comparative-1 LiQ 3.58 7.18 68 example Example-1 A-1 LiQ 3.54 7.33 83

[0252] 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.