Organic Electronic Device and Display Device Comprising the Organic Electronic Device as Well as a Composition for Use in Organic Electronic Devices

Abstract

The present invention relates to an organic electronic device comprising a semiconductor layer which comprises a mixture of isomeric compounds.

Claims

1. An organic electronic device comprising an anode layer, a cathode layer and at least one organic semiconductor layer, wherein the at least one organic semiconductor layer is arranged between the anode layer and the cathode layer; and wherein the at least one organic semiconductor layer comprises a composition comprising a compound of formula (I) ##STR00079## and at least one compound of formula (II) ##STR00080## Wherein B.sup.1 is selected of formula (IIIa) ##STR00081## B.sup.2 is selected of formula (IIIb) ##STR00082## B.sup.3 is selected of formula (IIIc) ##STR00083## wherein A.sup.1, A.sup.3 and A.sup.5 are independently selected from CN, partially or fully fluorinated C.sub.1 to C.sub.6 alkyl, partially or fully fluorinated C.sub.1 to C.sub.6 alkoxy, substituted or unsubstituted C.sub.6 to C.sub.18 aryl or C.sub.2 to C.sub.18 heteroaryl, wherein the substituents are selected from halogen, F, Cl, CN, partially or fully fluorinated C.sub.1 to C.sub.6 alkyl, partially or fully fluorinated C.sub.1 to C.sub.6 alkoxy; and A.sup.2, A.sup.4 and A.sup.6 are independently selected from substituted or unsubstituted C.sub.6 to C.sub.18 aryl or substituted or unsubstituted C.sub.2 to C.sub.18 heteroaryl, wherein the substituents are selected from halogen, F, Cl, CN, partially or fully fluorinated C.sub.1 to C.sub.6 alkyl, partially or fully fluorinated C.sub.1 to C.sub.6 alkoxy; and whereby the compound of formula (I) is different from the compound of formula (II) and the ratio of the compound of formula (I) and the compound of formula (II)—or the compounds of formula (II) if more than one is present—is ≥90:10.

2. The organic electronic device of claim 1, whereby the composition comprises more than one compound of formula (II), which are all different from each other as well as from the compound of formula (I).

3. The organic electronic device of claim 1, whereby the composition comprises a compound of formula (I) and at least one compound of formulae (IIa) to (IId) ##STR00084##

4. The organic electronic device of claim 1, whereby at least one A.sup.2, A.sup.4 and A.sup.6 is selected from C.sub.6 to C.sub.12 aryl or substituted or unsubstituted C.sub.3 to C.sub.12 heteroaryl, wherein the substituents are selected from halogen, F, Cl, CN, partially or fully fluorinated C.sub.1 to C.sub.4 alkyl, partially or fully fluorinated C.sub.1 to C.sub.4 alkoxy.

5. The organic electronic device of claim 1, whereby at least one from A.sup.2, A.sup.4 and A.sup.6 is selected from substituted or unsubstituted phenyl, pyridinyl or pyrimidyl, wherein the substituents are selected from halogen, F, Cl, CN, partially or fully fluorinated C.sub.1 to C.sub.4 alkyl, partially or fully fluorinated C.sub.1 to C.sub.4 alkoxy.

6. The organic electronic device of claim 1, whereby A.sup.1, A.sup.3 and A.sup.5 are independently selected from CN, partially or fully fluorinated C.sub.1 to C.sub.4 alkyl, partially or fully fluorinated C.sub.1 to C.sub.4 alkoxy, substituted or unsubstituted C.sub.6 to C.sub.12 aryl or C.sub.3 to C.sub.12 heteroaryl, wherein the substituents are selected from halogen, F, Cl, CN, partially or fully fluorinated C.sub.1 to C.sub.4 alkyl, partially or fully fluorinated C.sub.1 to C.sub.4 alkoxy

7. The organic electronic device of claim 1, whereby at least one from A.sup.2, A.sup.4 and A.sup.6 is substituted with at least one CF.sub.3, OCF.sub.3 or CN group or at least two F atoms.

8. The organic electronic device of claim 1, whereby at least one from A.sup.2, A.sup.4 and A.sup.6 is fully substituted.

9. The organic device of claim 1, whereby at least one from A.sup.1, A.sup.3 and A.sup.5 is CN.

10. The organic electronic device of claim 1, whereby the organic electronic device comprises at least one photoactive layer and the at least one of the at least one organic semiconductor layers is arranged between the anode and the at least one photoactive layer.

11. The organic electronic device of claim 1, whereby the organic electronic device comprises at least two photoactive layers, wherein at least one of the at least one organic semiconductor layers is arranged between the first and the second photoactive layer.

12. The organic electronic device of claim 1, whereby the at least one organic semiconductor layer further comprises a substantially covalent matrix compound.

13. The organic electronic device of claim 1, whereby the electronic organic device is an electroluminescent device.

14. A display device comprising an organic electronic device according to claim 1.

15. A composition comprising a compound of formula (I) ##STR00085## and at least one compound of formula (II) ##STR00086## wherein B.sup.1 is selected of formula (IIIa) ##STR00087## B.sup.2 is selected of formula (IIIb) ##STR00088## B.sup.3 is selected of formula (IIIc) ##STR00089## wherein A.sup.1, A.sup.3 and A.sup.5 are independently selected from CN, partially or fully fluorinated C.sub.1 to C.sub.6 alkyl, partially or fully fluorinated C.sub.1 to C.sub.6 alkoxy, substituted or unsubstituted C.sub.6 to C.sub.18 aryl or C.sub.2 to C.sub.18 heteroaryl, wherein the substituents are selected from halogen, F, Cl, CN, partially or fully fluorinated C.sub.1 to C.sub.6 alkyl, partially or fully fluorinated C.sub.1 to C.sub.6 alkoxy; and A.sup.2, A.sup.4 and A.sup.6 are independently selected from substituted or unsubstituted C.sub.6 to C.sub.18 aryl or substituted or unsubstituted C.sub.2 to C.sub.18 heteroaryl, wherein the substituents are selected from halogen, F, Cl, CN, partially or fully fluorinated C.sub.1 to C.sub.6 alkyl, partially or fully fluorinated C.sub.1 to C.sub.6 alkoxy; and whereby the compound of formula (I) is different from the compound of formula (II) and the ratio of the compound of formula (I) and the compound of formula (II)—or the compounds of formula (II) if more than one is present—is ≥90:10.

Description

DESCRIPTION OF THE DRAWINGS

[0228] The aforementioned components, as well as the claimed components and the components to be used in accordance with the invention in the described embodiments, are not subject to any special exceptions with respect to their size, shape, material selection and technical concept such that the selection criteria known in the pertinent field can be applied without limitations.

[0229] Additional details, characteristics and advantages of the object of the invention are disclosed in the dependent claims and the following description of the respective figures which in an exemplary fashion show preferred embodiments according to the invention. Any embodiment does not necessarily represent the full scope of the invention, however, and reference is made therefore to the claims and herein for interpreting the scope of the invention. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the present invention as claimed.

[0230] FIG. 1 is a schematic sectional view of an organic electronic device, according to an exemplary embodiment of the present invention;

[0231] FIG. 2 is a schematic sectional view of an organic light-emitting diode (OLED), according to an exemplary embodiment of the present invention;

[0232] FIG. 3 is a schematic sectional view of an OLED, according to an exemplary embodiment of the present invention.

[0233] Hereinafter, the figures are illustrated in more detail with reference to examples. However, the present disclosure is not limited to the following figures.

[0234] 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.

[0235] FIG. 1 is a schematic sectional view of an organic electronic device 100, according to an exemplary embodiment of the present invention. The organic electronic device 100 includes a substrate 110, an anode layer 120 and a hole injection layer (HIL) (130). The HIL 130 is disposed on the anode layer 120. Onto the HIL 130, a photoactive layer (PAL) 170 and a cathode layer 190 are disposed.

[0236] FIG. 2 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 layer 120 and a hole injection layer (HIL) 130, The HIL 130 is disposed on the anode layer 120. Onto the HIL 130, a hole transport layer (HTL) 140, an emission layer (EML) 150, an electron transport layer (ETL) 160, an electron injection layer (EIL) 180 and a cathode layer 190 are disposed. Instead of a single electron transport layer 160, optionally an electron transport layer stack (ETL) can be used.

[0237] FIG. 3 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.

[0238] Referring to FIG. 3, the OLED 100 includes a substrate 110, an anode layer 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 layer 190.

[0239] While not shown in FIG. 1, FIG. 2 and FIG. 3, a capping and/or sealing layer may further be formed on the cathode layer 190, in order to seal the organic electronic device 100. In addition, various other modifications may be applied thereto.

[0240] 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.

DETAILED DESCRIPTION

[0241] The invention is furthermore illustrated by the following examples which are illustrative only and non-binding.

General Procedures for Synthesis of the Compositions.

[0242] In the following a general procedure is given for the synthesis of the inventive compositions and for the comparative composition:

[0243] A flame dried Schlenk flask was charged with anhydrous cesium carbonate (6 equivalents) under inert gas. The flask was cooled on ice and dry DMF (8 mL) was added. The mixture was stirred on ice for 10 minutes before a solution of Reagent 2 (1.05 equivalents) in DMF (2 mL) was added dropwise. Subsequently, 1 g of Reagent 1 was added. After 20 minutes stirring on ice, the cooling bath was removed and the mixture allowed to warm to room temperature. The reaction was monitored via TLC (DCM/MeOH v:v 4:1). The base was filtered off and washed with t-Butylacetate (40 mL). The combined organic phases were washed with half-concentrated calcium chloride solution (3×30 mL) dried over sodium sulfate and the solvent was removed. The product is dissolved in glacial acetic acid (10 mL) and added dropwise to aqueous nitric acid (65% w/w, 13 ml plus 3 mL acetic acid) at 0° C. under stirring. The solution turned from black/green to red/orange. After stirring for 30 minutes at 0° C., the solution was allowed to warm to room temperature and was stirred for additional 1-4 h water. The crude product was precipitated by adding 10 mL water dropwise. The mixture was stirred for 15 min. Filtration gave an orange solid, which was washed with cold water until the filtrate was pH neutral. The crude product was dissolved in DCM and washed with water two times to remove remaining acid. The product was dried in vacuo.

[0244] A composition according to invention may be obtained by the following methods: [0245] One or more recrystallization steps from halogenated solvents, for example acetonitrile or DCM; and/or [0246] One or more precipitation steps from alkanes, for example hexane, heptane and/or cyclohexane.

[0247] The composition according to invention may be dried in vacuo, optionally followed by distillation or sublimation in vacuo.

Determination of the Ratio of Compounds:

[0248] The ratio of compound of formula (I) to compound of formula (II) may be determined for example by normal phase HPLC. For this purpose, a commercially available silica column and a UV-Vis diode array detector may be used. The composition according to invention may be dissolved in dichloromethane and injected. Suitable mobile phases may comprise cyclohexane, dichloromethane, or similar. A small amount trifluoroacetic acid may be added to the mobile phase to improve separation.

General Procedure for Fabrication of OLEDs

[0249] For bottom emission devices, see Table 2, a 15 Ω/cm.sup.2 glass substrate with 90 nm ITO (available from Corning Co.) was cut to a size of 50 mm×50 mm×0.7 mm, ultrasonically washed with isopropyl alcohol for 5 minutes and then with pure water for 5 minutes, and washed again with UV ozone for 30 minutes, to prepare the anode layer.

[0250] Then, Biphenyl-4-yl(9,9-diphenyl-9H-fluoren-2-yl)-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-amine (CAS 1242056-42-3) and composition according to Table 2 were vacuum deposited on the anode layer, to form a HIL having a thickness of 10 nm. The concentration of the composition in the HIL can be seen in Table 2.

[0251] 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 first HTL having a thickness of 118 nm.

[0252] 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.

[0253] Then 97 vol.-% H09 (Sun Fine Chemicals, Korea) as EML host and 3 vol.-% BD200 (Sun Fine Chemicals, Korea) as fluorescent blue dopant were deposited on the EBL, to form a first blue-emitting EML with a thickness of 20 nm.

[0254] Then the hole blocking layer is formed with a thickness of 5 nm by depositing 2-(3′-(9,9-dimethyl-9H-fluoren-2-yl)-[1,1′-biphenyl]-3-yl)-4,6-diphenyl-1,3,5-triazine on the emission layer.

[0255] Then, the electron transporting layer (ETL) having a thickness of 25 nm is formed on the hole blocking layer by depositing 50 wt.-% 4′-(4-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)naphthalen-1-yl)-[1,1′-biphenyl]-4-carbonitrile and 50 wt.-% LiQ.

[0256] Al is evaporated at a rate of 0.01 to 1 Å/s at 10.sup.−7 mbar to form a cathode with a thickness of 100 nm.

[0257] 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.

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 (calibrated by Deutsche Akkreditierungsstelle (DAkkS)) 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.

[0258] In bottom emission devices, the emission is predominately Lambertian and quantified in percent external quantum efficiency (EQE). To determine the efficiency EQE in % the light output of the device is measured using a calibrated photodiode at 10 mA/cm2.

In top emission devices, the emission is forward directed, non-Lambertian and also highly dependent on the micro-cavity. Therefore, the efficiency EQE will be higher compared to bottom emission devices. To determine the efficiency EQE in % the light output of the device is measured using a calibrated photodiode at 10 mA/cm2.

[0259] Lifetime LT of the device is measured at ambient conditions (20° C.) and 30 mA/cm.sup.2, using a Keithley 2400 sourcemeter, and recorded in hours.

[0260] 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.

Technical Effect of the Invention

[0261] In order to investigate the usefulness of the inventive compound preferred materials were tested in view of yield, and efficiency.
In the following Table 1a the structure of 7 inventive compositions (abbreviated as E1 to E7) are listed

TABLE-US-00001 Ratio Ratio of of formula formula A.sup.1 A.sup.2 A.sup.3 (I) [%] (II) [%] E1 [00054] [00055] [00056] 99.8 0.2 E2 [00057] [00058] [00059] 98 2 E3 [00060] [00061] [00062] 95 5 E4 [00063] [00064] [00065] 91 9 E5 [00066] [00067] [00068] 99.4 0.6 E6 [00069] [00070] [00071] 97 3 E7 [00072] [00073] [00074] 92 8
The comparative examples 1 to 2 were identical to inventive examples 1 to 4, only that the ratio of the compound of formula (I) was as 8500 and 75%, respectively.
The comparative example 3 was identical to inventive examples 5 to 7, only that the ratio of the compound of formula (I) was 8500.
In the following Table 1b the reagents out of which the examples were synthesized are listed:

TABLE-US-00002 Composition Reagent 1 Reagent 2 Inventive Examples 1 to 4 [00075] [00076] Inventive Examples 5 to 7 [00077] [00078]
In Table 2 are shown OLED data for compositions according to invention and comparative examples 1 to 3

TABLE-US-00003 Cd/A U efficiency EQE Concentration at 15 at 15 at 15 LT97 Composition composition mA/cm.sup.2 mA/cm.sup.2 mA/cm.sup.2 at 30 used [vol.-%] [V] [cd/A] [%] mA/cm.sup.2 Inventive 3.1 4.2 8.05 8.8 75 h example 1 Inventive 3.1 4.19 8.0 8.78 74 h example 2 Inventive 3.1 4.21 8.03 8.82 71 h example 3 Inventive 3.1 4.2 8.04 8.76 73 h example 4 Comparative 3.1 4.4 7.84 8.6 65 h example 1 Comparative 3.1 4.54 7.78 8.63 60 h example 2 Inventive 3.1 3.85 8.2 8.9 73 h example 5 Inventive 3.1 3.82 8.25 8.97 72 h example 6 Inventive 3.1 3.85 8.18 8.88 68 example 7 Comparative 3.1 4.1 8.2 8.9 63 example 3

[0262] Surprisingly, it was found that operating voltage, cd/A efficiency, EQE and/or lifetime are essentially unchanged when the composition according to invention is used, see inventive examples 1 to 7.

[0263] When the ratio of the compound(s) of formula (II) in the composition exceeds 10%, the operating voltage may be increased and/or the cd/A efficiency, EQE and/or lifetime may be reduced.

[0264] A low operating voltage and/or an high cd/A efficiency and EQE may lead to a reduction in power consumption, in particular in mobile devices.

[0265] A long lifetime may lead to improved long-term stability of organic electronic devices.

[0266] The particular combinations of elements and features in the above detailed embodiments are exemplary only; the interchanging and substitution of these teachings with other teachings in this and the patents/applications incorporated by reference are also expressly contemplated. As those skilled in the art will recognize, variations, modifications, and other implementations of what is described herein can occur to those of ordinary skill in the art without departing from the spirit and the scope of the invention as claimed. Accordingly, the foregoing description is by way of example only and is not intended as limiting. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. The invention's scope is defined in the following claims and the equivalents thereto. Furthermore, reference signs used in the description and claims do not limit the scope of the invention as claimed.