Organic Electronic Device Comprising a Compound of Formula (1), Display Device Comprising the Organic Electronic Device as Well as Compounds of Formula (1) for Use in Organic Electronic Devices

Abstract

The present invention relates to an organic electronic device comprising a semiconductor layer which comprises a compound of formula (I).

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 compound of formula (I) ##STR00069## whereby A.sup.1 is selected from formula (II) ##STR00070## whereby R.sup.1 is selected from partially or perfluorinated C.sub.1 to C.sub.6 alkyl or CN, R.sup.2 is selected partially or perfluorinated C.sub.1 to C.sub.6 alkyl, X.sup.1 is selected from CH or N; X.sup.2 and X.sup.3 are independently selected from CH, CF or N; and A.sup.1 is linked to the cyclopropene core via the atom marked as “*”; R.sup.3 is 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 and A.sup.3 are independently selected from formula (III), ##STR00071## wherein Ar is independently selected from substituted or unsubstituted C.sub.6 to C.sub.18 aryl and substituted or unsubstituted C.sub.2 to C.sub.18 heteroaryl, wherein the substituents on Ar are independently selected from CN, partially or perfluorinated C.sub.1 to C.sub.6 alkyl, halogen, F.

2. The organic electronic device of claim 1, whereby the compound is selected of the formula (IV) ##STR00072## whereby B.sub.1 is selected from formula (V) ##STR00073## B.sub.3 and B.sub.5 are Ar and B.sub.2, B.sub.4 and B.sub.6 are R.sup.3.

3. The organic electronic device of claim 1, whereby R.sup.1 is selected from perfluorinated C.sub.1 to C.sub.6 alkyl or CN.

4. The organic electronic device of claim 1, whereby R.sup.2 is selected from perfluorinated C.sub.1 to C.sub.6 alkyl.

5. The organic electronic device of claim 1, whereby R.sup.3 is 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.

6. The organic electronic device of claim 1, whereby at least one from A.sup.2 and A.sup.3 is identical to A.sup.1.

7. The organic electronic device of claim 1, whereby in formula (II) at least one of X.sup.1, X.sup.2 and X.sup.3 is selected from CH.

8. The organic device of claim 1, whereby in formula (II) X.sup.1 and X.sup.2 are independently selected from CH or N and X.sup.3 is selected from CH.

9. The organic device of claim 1, whereby R.sup.1 is selected from perfluorinated C.sub.1 to C.sub.4 alkyl or CN.

10. The organic electronic device of claim 1, whereby the organic semiconductor layer comprises a composition comprising a compound of formula (IV) and at least one compound of formula (IVa) to (IVd) ##STR00074##

11. 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.

12. 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.

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 compound of formula (I) ##STR00075## whereby A.sup.1 is selected from formula (II) ##STR00076## whereby R.sup.1 is selected from partially or perfluorinated C.sub.1 to C.sub.6 alkyl or CN, R.sup.2 is selected partially or perfluorinated C.sub.1 to C.sub.6 alkyl, X.sup.1 is selected from CH or N; X.sup.2 and X.sup.3 are independently selected from CH, CF or N; and A.sup.1 is linked to the cyclopropene core via the atom marked as “*”; R.sup.3 is 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 and A.sup.3 are independently selected from formula (III), ##STR00077## Wherein Ar is independently selected from substituted or unsubstituted C.sub.6 to C.sub.18 aryl and substituted or unsubstituted C.sub.2 to C.sub.18 heteroaryl, wherein the substituents on Ar are independently selected from CN, partially or perfluorinated C.sub.1 to C.sub.6 alkyl, halogen, F.

Description

DESCRIPTION OF THE DRAWINGS

[0229] 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.

[0230] 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.

[0231] FIG. 1 is a schematic sectional view of an organic electronic device, according to an exemplary embodiment of the present invention;

[0232] FIG. 2 is a schematic sectional view of an organic light-emitting diode (OLED), according to an exemplary embodiment of the present invention;

[0233] FIG. 3 is a schematic sectional view of an OLED, according to an exemplary embodiment of the present invention.

[0234] Hereinafter, the figures are illustrated in more detail with reference to examples. However, the present disclosure is not limited to the following figures.

[0235] 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.

[0236] 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.

[0237] 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.

[0238] FIG. 3 is a schematic sectional view of an OLED 100, according to another exemplary embodiment of the present invention. FIG. 3 differs from FIG. 2 in that the OLED 100 of FIG. 3 comprises an electron blocking layer (EBL) 145 and a hole blocking layer (HBL) 155.

[0239] 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.

[0240] While not shown in FIG. 1, FIG. 2 and FIG. 3, a sealing and/or capping 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.

[0241] 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

[0242] The invention is furthermore illustrated by the following examples which are illustrative only and non-binding.

[0243] Compounds of formula (I) may be prepared as described in EP2180029A1 and WO2016097017A1.

Calculated HOMO and LUMO

[0244] 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.

Rate Onset Temperature

[0245] 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 Com-pany (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.

[0246] 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.

[0247] 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.

[0248] According to one embodiment, the rate onset temperature of compound of formula (I) is selected in the range of ≥120° C. and ≤300° C.; preferably of ≥125° C. and ≤280° C.

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.

[0250] Then, Biphenyl-4-yl(9,9-diphenyl-9H-fluoren-2-O-[4-(9-phenyl-9H-carbazol yl)phenyl]-amine (CAS 1242056-42-3) and compound of formula (I) according to Table 2 were vacuum deposited on the anode, to form a HIL having a thickness of 10 nm. The amount of compound of formula (I) 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.

[0259] In top emission devices, the emission is forward directed, non-Lambertian and also highly dependent on the mirco-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/cm.sup.2.

[0260] 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.

[0261] 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

[0262] In Table 1 are shown LUMO levels and rate onset temperatures T.sub.RO (when available) for Examples 1 to 11 (=E1 to Ell) and comparative example 1 and 2 (═C.sub.1 and C.sub.2). In all examples and comparative examples, the compounds were essentially isomer free and resembled the structure of formula (IV) as described above.

[0263] LUMO levels were calculated with the program package TURBOMOLE V6.5 (TURBOMOLE GmbH, Litzenhardtstrasse 19, 76135 Karlsruhe, Germany) by applying the hybrid functional B3LYP with a 6-31G* basis set in the gas phase.

[0264] In comparative example 1, the calculated LUMO level is −4.40 eV. R.sup.1 and R.sup.2 are selected from OCF.sub.3. A.sup.2 is selected from formula (Ma), wherein Wand R.sup.2 are selected from OCF.sub.3. Ar in A.sup.3 is selected from 2,4-bis(trifluoromethoxy)phenyl.

[0265] In comparative example 2, the calculated LUMO level is −4.34 eV. R.sup.1 and R.sup.2 are selected from F. A.sup.2 and A.sup.3 are selected from formula (Ma), wherein R.sup.1 and R.sup.2 are selected from F.

[0266] In Example 1, the LUMO level is shown. Example 1 differs from comparative example 1 in the selection of R.sup.1 and R.sup.2 in formula (II) and formula (Ma). In the example, R.sup.1 and R.sup.2 in formula (II) and formula (Ma) are selected from CF.sub.3. The LUMO level is improved to −4.92 eV. Without being bound by theory, a LUMO level further away from vacuum level may improve doping strength of matrix compounds.

[0267] In Example 2, the LUMO level and T.sub.RO are is shown. Example 2 differs from Example 1 in the selection of A.sup.2 and A.sup.3. A.sup.2 and A.sup.3 comprise phenyl groups substituted with four F atoms and one CF.sub.3 group. The LUMO level is improved over comparative examples 1 and 2. Additionally, the rate onset temperature is in a range which is suitable for mass production of organic electronic devices.

[0268] In Examples 3 to 11, the LUMO level is improved over comparative examples 1 and 2, see Table 1.

[0269] In summary, improved LUMO levels have been obtained. Additionally, the rate onset temperature is in a range suitable for mass production of organic electronic devices.

TABLE-US-00001 TABLE 1 Properties of compounds of formula (1) and comparative examples 1 and 2 Calculated LUMO T.sub.RO A.sup.1 A.sup.2 A.sup.3 [eV] [° C.] C1 [00030] [00031] [00032] −4.40 — C2 [00033] [00034] [00035] −4.34 — E1 [00036] [00037] [00038] −4.92 — E2 [00039] [00040] [00041] −4.82 136 E3 [00042] [00043] [00044] −5.07 156 E4 [00045] [00046] [00047] −4.93 153 E5 [00048] [00049] [00050] −5.33 — E6 [00051] [00052] [00053] −5.50 — E7 [00054] [00055] [00056] −4.96 — E8 [00057] [00058] [00059] −5.61 — E9 [00060] [00061] [00062] −4.95 — E10 [00063] [00064] [00065] −5.58 — E11 [00066] [00067] [00068] −5.36 —

[0270] In Table 2 are shown operating voltage, cd/A efficiency, EQE and LT97 of organic electronic devices comprising an organic semiconductor layer comprising compound of formula (I).

TABLE-US-00002 TABLE 2 Organic electronic devices comprising an organic semiconductor layer comprising compound of formula (I) Cd/A Vol.-% efficiency EQE LT97 Compound compound U at 10 at 10 at 10 at 30 Device of formula of formula mA/cm.sup.2 mA/cm.sup.2 mA/cm.sup.2 mA/cm.sup.2 No. (I) (I) [V] [cd/A] [%] [h] 1 Example 2 7.9 4.4 8.7 9.4 135 2 Example 2 16 3.9 8.6 9.3 122 3 Example 3 8 3.8 9 9.6 103 4 Example 4 8 3.9 9.1 9.8 103

[0271] In device No. 1, the organic semiconductor layer comprises 7.9 vol.-% Example 2. The operating voltage is 4.4 V, the cd/A efficiency is 8.7 cd/A, the external quantum efficiency EQE is 9.4% and the LT97 is 135 hours.

[0272] In device No. 2, the organic semiconductor layer comprises 16 vol.-% Example 2. The operating voltage is reduced to 3.9 V, the cd/A efficiency is 8.6 cd/A, the external quantum efficiency EQE is 9.3% and the LT97 is 122 hours.

[0273] In device No. 3, the organic semiconductor layer comprises 8 vol.-% Example 3. The operating voltage is further reduced to 3.8 V, the cd/A efficiency is improved to 9 cd/A, the external quantum efficiency EQE is improved to 9.6% and the LT97 is 103 hours.

[0274] In device No. 4, the organic semiconductor layer comprises 8 vol.-% Example 4. The operating voltage is 3.9 V, the cd/A efficiency is improved to 9.1 cd/A, the external quantum efficiency EQE is further improved to 9.8% and the LT97 is 103 hours.

[0275] A low operating voltage may be beneficial for reduced power consumption and improved battery life, in particular in mobile devices.

[0276] A high cd/A efficiency and/or EQE may be beneficial for reduced power consumption and improved battery life, in particular in mobile devices.

[0277] An improved LT97 may be beneficial for long lifetime of organic electronic devices.

[0278] 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.