An Organic Electronic Device Comprising a Substrate, an Anode Layer, a Cathode Layer, at Least One First Emission Layer, and a Hole Injection Layer, Wherein the Hole Injection Layer Comprises a Metal Complex of Formula (I) and a Compound of Formula (II), Wherein the Hole Injection Layer is Arranged Between the Anode Layer and the at Least One First Emission Layer
20240415007 ยท 2024-12-12
Inventors
Cpc classification
H10K85/6572
ELECTRICITY
C09K2211/187
CHEMISTRY; METALLURGY
H10K85/331
ELECTRICITY
C09K2211/1029
CHEMISTRY; METALLURGY
H10K85/371
ELECTRICITY
H10K85/633
ELECTRICITY
C09K2211/188
CHEMISTRY; METALLURGY
International classification
Abstract
The present invention relates to an organic electronic device comprising a substrate, an anode layer, a cathode layer, at least one first emission layer, and a hole injection layer, wherein the hole injection layer comprises a metal complex of formula (I) and a compound of formula (II), wherein the hole injection layer is arranged between the anode layer and the at least one first emission layer.
Claims
1. An organic electronic device comprising a substrate, an anode layer, a cathode layer, at least one first emission layer, and a hole injection layer, wherein the hole injection layer comprises a metal complex of formula (I): ##STR00036## wherein M is a metal; L is a charge-neutral ligand, which coordinates to the metal M; n is an integer selected from 1 to 4, which corresponds to the oxidation number of M; m is an integer selected from 0 to 2; R.sup.1 and R.sup.3 are independently selected from H, D, substituted or unsubstituted C.sub.1 to C.sub.12 alkyl, substituted or unsubstituted C.sub.1 to C.sub.12 alkoxy, substituted or unsubstituted C.sub.6 to C.sub.24 aryl, and substituted or unsubstituted C.sub.2 to C.sub.24 heteroaryl group, wherein at least one substituent is selected from halogen, F, C.sub.1, CN, substituted or unsubstituted C.sub.1 to C.sub.12 alkyl, partially or fully fluorinated C.sub.1 to C.sub.12 alkyl, substituted or unsubstituted C.sub.1 to C.sub.12 alkoxy, partially or fully fluorinated C.sub.1 to C.sub.12 alkoxy, 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 of the substituted or unsubstituted C.sub.1 to C.sub.12 alkyl, substituted or unsubstituted C.sub.1 to C.sub.12 alkoxy, substituted or unsubstituted C.sub.6 to C.sub.18 aryl, and substituted or unsubstituted C.sub.2 to C.sub.18 heteroaryl are selected from halogen, F, Cl, CN, C.sub.1 to C.sub.6 alkyl, CF.sub.3, OCH.sub.3, OCF.sub.3; R.sup.2 is selected from CN, C.sub.1 to C.sub.4 alkyl, partially or perfluorinated C.sub.1 to C.sub.4 alkyl, or F; wherein at least one R.sup.1 and/or R.sup.3 is selected from a substituted C.sub.6 to C.sub.24 aryl or substituted C.sub.2 to C.sub.24 heteroaryl group, wherein at least one substituent of the substituted C.sub.6 to C.sub.24 aryl or substituted C.sub.2 to C.sub.24 heteroaryl group is selected from CN or partially or fully fluorinated C.sub.1 to C.sub.12 alkyl; and a compound of formula (II) ##STR00037## T.sup.1, T.sup.2, T.sup.3 are independently selected from a single bond, phenylene, biphenylene, terphenylene or naphthenylene; Ar.sup.1, Ar.sup.2, Ar.sup.3 are independently selected from substituted or unsubstituted C.sub.6 to C.sub.20 aryl, or substituted or unsubstituted C.sub.3 to C.sub.20 heteroarylene, substituted or unsubstituted biphenylene, substituted or unsubstituted fluorene, substituted 9-fluorene, substituted 9,9-fluorene, substituted or unsubstituted naphthalene, substituted or unsubstituted anthracene, substituted or unsubstituted phenanthrene, substituted or unsubstituted pyrene, substituted or unsubstituted perylene, substituted or unsubstituted triphenylene, substituted or unsubstituted tetracene, substituted or unsubstituted tetraphene, substituted or unsubstituted dibenzofurane, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted xanthene, substituted or unsubstituted carbazole, substituted 9-phenylcarbazole, substituted or unsubstituted azepine, substituted or unsubstituted dibenzo[b,f]azepine, substituted or unsubstituted 9,9-spirobi[fluorene], substituted or unsubstituted spiro[fluorene-9,9-xanthene], or a substituted or unsubstituted aromatic fused ring system comprising at least three substituted or unsubstituted aromatic rings selected from the group comprising substituted or unsubstituted non-hetero, substituted or unsubstituted hetero 5-member rings, substituted or unsubstituted 6-member rings and/or substituted or unsubstituted 7-member rings, substituted or unsubstituted fluorene, or a fused ring system comprising 2 to 6 substituted or unsubstituted 5- to 7-member rings and the rings are selected from the group comprising (i) unsaturated 5- to 7-member ring of a heterocycle, (ii) 5- to 6-member of an aromatic heterocycle, (iii) unsaturated 5- to 7-member ring of a non-heterocycle, (iv) 6-member ring of an aromatic non-heterocycle; wherein the substituents of Ar.sup.1, Ar.sup.2, Ar.sup.3 are selected the same or different from the group comprising H, D, F, CN, Si(R.sup.2).sub.3, substituted or unsubstituted straight-chain alkyl having 1 to 20 carbon atoms, substituted or unsubstituted branched alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cyclic alkyl having 3 to 20 carbon atoms, substituted or unsubstituted alkenyl or alkynyl groups having 2 to 20 carbon atoms, substituted or unsubstituted aromatic ring systems having 6 to 40 aromatic ring atoms, and substituted or unsubstituted heteroaromatic ring systems having 5 to 40 aromatic ring atoms, unsubstituted C.sub.6 to C.sub.18 aryl, unsubstituted C.sub.3 to C.sub.18 heteroaryl, a fused ring system comprising 2 to 6 unsubstituted 5- to 7-member rings and the rings are selected from the group comprising unsaturated 5- to 7-member ring of a heterocycle, 5- to 6-member of an aromatic heterocycle, unsaturated 5- to 7-member ring of a non-heterocycle, and 6-member ring of an aromatic non-heterocycle, wherein R.sup.2 may be selected from H, D, straight-chain alkyl having 1 to 6 carbon atoms, branched alkyl having 1 to 6 carbon atoms, cyclic alkyl having 3 to 6 carbon atoms, alkenyl or alkynyl groups having 2 to 6 carbon atoms, Co to C.sub.18 aryl or C.sub.3 to C.sub.18 heteroaryl; wherein the hole injection layer is arranged between the anode layer and the at least one first emission layer.
2. The organic electronic device according to claim 1, wherein M is selected from Li(I), Na(I), K(I), Rb(I), Cs(I), Cu(II), Zn(II), Pd(II), Al(III), Sc(III), Mn(III), In(III), Y(III), Eu(III), Fe(III), Zr(IV), Hf(IV) or Ce(IV).
3. The compound according to claim 1, wherein L is selected from the group comprising H.sub.2O, C.sub.2 to C.sub.40 mono- or multi-dentate ethers and C.sub.2 to C.sub.40 thioethers, C.sub.2 to C.sub.40 amines, C.sub.2 to C.sub.40 phosphine, C.sub.2 to C.sub.20 alkyl nitrile or C.sub.2 to C.sub.40 aryl nitrile, or a compound according to Formula (II); ##STR00038## wherein R.sup.6 and R.sup.7 are independently selected from C.sub.1 to C.sub.20 alkyl, C.sub.1 to C.sub.20 heteroalkyl, Co to C.sub.20 aryl, heteroaryl with 5 to 20 ring-forming atoms, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.1 to C.sub.20 heteroalkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms, or at least one R.sup.6 and R.sup.7 are bridged and form a 5 to 20 member ring, or the two R.sup.6 and/or the two R.sup.7 are bridged and form a 5 to 40 member ring or form a 5 to 40 member ring comprising an unsubstituted or C.sub.1 to C.sub.12 substituted phenanthroline.
4. The compound according to claim 1, wherein n is an integer selected from 1, 2 and 3, which corresponds to the oxidation number of M.
5. The organic electronic device according to claim 1, wherein R.sup.2 is selected from CN, CH.sub.3, CF.sub.3, C.sub.2F.sub.5, C.sub.3F.sub.7 or F.
6. The organic electronic device according to claim 1, wherein the metal complex of formula (I) comprises at least one CF.sub.3 group.
7. The organic electronic device according to claim 1, wherein the R.sup.1 and/or R.sup.3 each are substituted by a maximum number of four substituents.
8. The organic electronic device according to claim 1, wherein at least one R.sup.1 and/or R.sup.3 is selected from a substituted C.sub.6 to C.sub.24 aryl or substituted C.sub.2 to C.sub.24 heteroaryl group, wherein at least one substituent of the substituted C.sub.6 to C.sub.24 aryl or substituted C.sub.2 to C.sub.24 heteroaryl group is selected from CN or partially or fully fluorinated C.sub.1 to C.sub.12 alkyl.
9. The organic electronic device according to claim 1, wherein at least one substituted or unsubstituted C.sub.6 to C.sub.24 aryl or substituted or unsubstituted C.sub.2 to C.sub.24 heteroaryl of R.sup.1 and/or R.sup.3 is selected from the following formulae D1 to D71: ##STR00039## ##STR00040## ##STR00041## ##STR00042## ##STR00043## ##STR00044## ##STR00045## ##STR00046## wherein the * denotes the binding position.
10. The organic electronic device according to claim 1, wherein the metal complex of formula (I) is selected from one of the following formulae: ##STR00047## ##STR00048## ##STR00049## ##STR00050## ##STR00051##
11. The organic electronic device according to claim 1, wherein the compound of formula (II) has a HOMO level smaller than the HOMO level of N2,N2,N2,N2,N7,N7,N7,N7-octakis (4-methoxyphenyl)-9,9-spirobi[fluorene]-2,2,7,7-tetraamine, when determined by the same method.
12. The organic electronic device according to claim 1, wherein the compound of formula (II) is selected from one of the following formulae K1 to K16: ##STR00052## ##STR00053## ##STR00054##
13. The organic electronic device according to claim 1, wherein the organic electronic device further comprises a hole transport layer, wherein the hole transport layer is arranged between the hole injection layer and the at least one emission layer.
14. The organic electronic device according to claim 13, wherein the hole transport layer comprises a matrix compound.
15. The organic electronic device according to claim 1, wherein the organic electronic device is a light emitting device or a display device.
Description
DESCRIPTION OF THE DRAWINGS
[0216] 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.
[0217] Additional details, characteristics and advantages of the object 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, however, and reference is made therefore to the claims and herein for interpreting the scope. 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.
FIGS. 1 to 8
[0218]
[0219]
[0220]
[0221]
[0222]
[0223]
[0224]
[0225]
[0226] Hereinafter, the
[0227] 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.
[0228]
[0229]
[0230]
[0231]
[0232]
[0233]
[0234]
[0235]
[0236] While not shown in
[0237] Hereinafter, the embodiments are illustrated in more detail with reference to examples. However, the present disclosure is not limited to the following examples.
DETAILED DESCRIPTION
[0238] The invention is furthermore illustrated by the following examples which are illustrative only and non-binding.
Metal Complexes of Formula (I)
[0239] Metal complexes of formula (I) may be prepared by known methods or as described below.
Synthesis of 2-(3,5-bis(trifluoromethyl)benzoyl)-3-(3,5-bis(trifluoromethyl)phenyl)-3-oxopropanenitrile
##STR00019##
[0240] To a solution of 17.37 g (35 mmol) of 1,3-bis(3,5-bis(trifluoromethyl)phenyl)propane-1,3-dione and K.sub.2CO.sub.3 (7.26 g, 52.5 mmol) in THF-water was added p-Tolylsulfonylcyanid (9.51 g, 52.5 mmol) in one portion and the resulting mixture was stirred at RT for 3 h. The reaction mixture was cooled to 0 C., acidified with aq. 2 M HCl, and extracted 2500 ml of ethyl acetate. The combined organic phases were dried over MgSO.sub.4 and concentrated. Crude product was triturated in mixture of 100 ml hexane and 10 ml ethyl acetate for 1 h. Solid precipitate was filtered and washed with hexane. Filtrate was purified by chromatography on silica gel (DCM/Ethyl acetate/Hexane). Fractions with product were concentrated followed by acidic extraction (aq. 2 M HCl/ethyl acetate). The combined organic phases were dried over MgSO.sub.4 and concentrated. Product was triturated in 20% Et.sub.2O in hexane for 2 h, solid was filtered, washed with hexane, and dried. Yield 9.52 g (52%).
Synthesis of bis(((Z)-1,3-bis(3,5-bis(trifluoromethyl)phenyl)-2-cyano-3-oxoprop-1-en-1-yl)oxy)copper (MC-1)
##STR00020##
[0241] 2.42 g (4.64 mmol) of 2-(3,5-bis(trifluoromethyl)benzoyl)-3-(3,5-bis(trifluoromethyl)phenyl)-3-oxopropanenitrile were dissolved in 40 ml methanol and solution of 0.46 g (2.32 mmol) copper (II) acetate monohydrate in 30 ml methanol and 20 ml water was added. The mixture was stirred at room temperature overnight. The precipitate was filtered off, washed with water and dried in high vacuum. 2.29 g (89%) product was obtained as a powder.
Synthesis of 2-(3,5-bis(trifluoromethyl)-[1,1-biphenyl]-4-carbonyl)-4,4,5,5,5-pentafluoro-3-oxopentanenitrile
##STR00021##
[0242] To a solution of 16.7 g (35 mmol) of 1-(3,5-bis(trifluoromethyl)-[1,1-biphenyl]-4-yl)-4,4,5,5,5-pentafluoropentane-1,3-dione and K.sub.2CO.sub.3 (7.26 g, 52.5 mmol) in THF-water was added p-Tolylsulfonylcyanid (9.51 g, 52.5 mmol) in one portion and the resulting mixture was stirred at RT for 20 h. THF was removed and 300 ml water and 300 ml DCM were added and stirred in ice/water bath for 30 min. White solid was filtered and washed with 2300 ml water and 2300 ml DCM and dried. Crude material was suspended in 100 ml DCM and 60 ml 1 M HCl for 30 min, Layers were separated. Organic phase was washed with 30 ml of 1 M HCl. Combined aq. phases were washed with 100 ml DCM. Combined organic phases were washed with 100 ml water, dried over MgSO.sub.4 and concentrated at 40 C. 100 ml hexane was added and stirred with 5 ml DCM in ice/water bath for 1 h. Solid was filtered, washed with cold hexane and dried. 14.27 g (yield 81%).
Synthesis of bis(((Z)-1-(3,5-bis(trifluoromethyl)-[1,1-biphenyl]-4-yl)-2-cyano-4,4,5,5,5-pentafluoro-3-oxopent-1-en-1-yl)oxy)copper (MC-2)
##STR00022##
[0243] 5.0 g (9.94 mmol) of 2-(3,5-bis(trifluoromethyl)-[1,1-biphenyl]-4-carbonyl)-4,4,5,5,5-pentafluoro-3-oxopentanenitrile were dissolved in 50 ml methanol and 0.99 g (4.97 mmol) copper (II) acetate monohydrate and 20 ml water were added. The mixture was stirred at room temperature overnight. The precipitate was filtered off, washed with water and dried in high vacuum. The crude product was crystallised from chloroform/ethyl acetate to obtain 3.60 g (68%) product as a solid.
Synthesis of N-methoxy-N-methyl-2-(trifluoromethyl)isonicotinamide
##STR00023##
[0244] Flask was charged with 2-(trifluoromethyl) isonicotinic acid (20.1 g, 100 mmol), dichloromethane (100 ml) and CDI (19.4 g, 120 mmol) was added within 10 min. RM (reaction mixture) was stirred at r.t. for 1.5 h. Then, N,O-dimethylhydroxylamine hydrochloride (14.6 g, 150 mmol) was added and reaction mixture was stirred at r.t. for 17 h (overnight). Reaction was quenched with 1 M sol. of NaOH (50 mL) and extracted with dichloromethane (2100 mL). Combined organic layers were washed with water, brine and solvent was evaporated in vacuo to give an oil (20.5 g, yield 87%).
Synthesis of 1-(2-(trifluoromethyl)pyridin-4-yl)propan-1-one
##STR00024##
[0245] Flask was charged with N-methoxy-N-methyl-2-(trifluoromethyl)isonicotinamide (20.3 g, 87 mmol), evacuated and filled with Ar. THF was added and RM (reaction mixture) was cooled to 79 C. Then, EtMgBr (3 M in THF, 130 mmol)) was added dropwise within 15 min. The reaction mixture was stirred at 79 C. for 1 h and then 0 C. for 2 h. Upon completion, the reaction mixture was poured into sol. of NH.sub.4Cl and extracted with Et.sub.2O. Obtained red oil was purified by column chromatography (hexane-ethyl acetate) to give product as a liquid (13.2, yield 74%).
Synthesis of 2-methyl-1,3-bis(2-(trifluoromethyl)pyridin-4-yl)propane-1,3-dione
##STR00025##
[0246] Flask was charged with 1-(2-(trifluoromethyl)pyridin-4-yl)propan-1-one (10.2 g, 50 mmol), evacuated and filled with Ar. THF was added, reaction mixture was cooled to 0 C. and NaH (2.4 g, 100 mmol) was added. Reaction mixture was stirred for 30 min. and 2,2,2-trifluoroethyl trifluoroacetate (5.9 g, 30 mmol) was added dropwise within 20 min and mixture was stirred at 0 C. for 30 min. Upon completion reaction was quenched at 0 C. by diluted HCl and extracted with Et.sub.2O, combined organic layers were washed with water, brine, dried over Na.sub.2SO.sub.4 and solvent was evaporated in vacuo. The residue was purified by column chromatography (Hexane, ethyl acetate). Obtained yellow solid was triturated with 20 mL of Et.sub.2O, filtrated off and washed with cold Et.sub.2O. Colourless product was obtained 4.42 g (47%).
Synthesis of bis(((Z)-2-methyl-3-oxo-1,3-bis(2-(trifluoromethyl)pyridin-4-yl)prop-1-en-1-yl)oxy)copper (MC-3)
##STR00026##
[0247] 2.50 g (6.64 mmol) of 2-methyl-1,3-bis(2-(trifluoromethyl)pyridin-4-yl)propane-1,3-dione were dissolved in 25 ml methanol and 0.66 g (3.32 mmol) copper (II) acetate monohydrate and 10 ml water were added. The mixture was stirred at room temperature overnight. The precipitate was filtered off, washed with water and dried in high vacuum. The crude product was stirred in 200 mL hot ethyl acetate, filtered off and dried in high vacuum to obtain 1.97 g (73%) product as a solid.
Synthesis of bis(((Z)-2-methyl-3-oxo-1,3-bis(2-(trifluoromethyl)pyridin-4-yl)prop-1-en-1-yl)oxy)copper (MC-4)
##STR00027##
[0248] 2.98 g (7.70 mmol) of 2-methyl-1,3-bis(2-(trifluoromethyl)pyridin-4-yl)propane-1,3-dione were dissolved in 60 ml methanol and 0.65 g (7.70 mmol) sodium bicarbonate was added. 0.41 g (2.57 mmol) iron trichloride were dissolved in 2 ml water and added dropwise to the reaction. The mixture was stirred at room temperature overnight. The precipitate was filtered off, washed with water and dried in high vacuum. 0.73 g (24%) product were obtained as a solid.
Synthesis of tris(((Z)-1,3-bis(3,5-bis(trifluoromethyl)phenyl)-2-cyano-3-oxoprop-1-en-1-yl)oxy) iron (MC-5/G8)
##STR00028##
[0249] 1.63 g (3.12 mmol) of 2-(3,5-bis(trifluoromethyl)benzoyl)-3-(3,5-bis(trifluoromethyl)phenyl)-3-oxopropanenitrile were dissolved in methanol and 0.26 g (3.12 mmol) sodium bicarbonate was added. 0.17 g (1.04 mmol) iron trichloride were dissolved in water and added to the mixture under cooling. The mixture was stirred at room temperature overnight. The precipitate was filtered off, washed with water and dried in high vacuum. 1.08 g (64%) Product was obtained as a powder.
[0250] Further compounds according to invention may be prepared by the methods described above or by methods known in the art.
TABLE-US-00001 TABLE 1 Formulae of comparative compounds CC-1 and CC-2 and metal complex of Formula (I) MC-1 to MC-5 Name Formula CC-1
Compounds of Formula (II)
[0251] Compounds of formula (II) may be prepared by methods known in the art.
HOMO and LUMO Levels
[0252] The HOMO and LUMO levels 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.
General Procedure for Fabrication of Organic Electronic Devices Comprising a Hole Injection Layer Comprising a Metal Complex and a Compound of Formula (II) Wherein the Hole Injection Layer is Deposited in Vacuum
[0253] For inventive examples 1-1 to 1-25 and comparative examples 1-1 to 1-4 in Table 2 a glass substrate with an anode layer comprising a first anode sub-layer of 120 nm Ag, a second anode sub-layer of 8 nm ITO and a third anode sub-layer of 10 nm ITO was cut to a size of 50 mm50 mm0.7 mm, ultrasonically washed with water for 60 minutes and then with isopropanol for 20 minutes. The liquid film was removed in a nitrogen stream, followed by plasma treatment to prepare the anode layer. The plasma treatment was performed in an atmosphere comprising 97.6 vol.-% nitrogen and 2.4 vol.-% oxygen.
[0254] Then, the compound of formula (II) and the metal complex were co-deposited in vacuum on the anode layer, to form a hole injection layer (HIL) having a thickness of 10 nm. The composition of the hole injection layer can be seen in Table 2. The formulae of the metal complexes can be seen in Table 1.
[0255] Then, the compound of formula (II) was vacuum deposited on the HIL, to form a HTL having a thickness of 123 nm. The compound of formula (II) in the HTL is selected the same as the compound of formula (II) in the HIL. The compound of formula (II) can be seen in Table 2.
[0256] Then N-(4-(dibenzo[b,d]furan-4-yl)phenyl)-N-(4-(9-phenyl-9H-fluoren-9-yl)phenyl)-[1,1-biphenyl]-4-amine (CAS 1824678-59-2) was vacuum deposited on the HTL, to form an electron blocking layer (EBL) having a thickness of 5 nm.
[0257] Then 97 vol.-% H09 as EML host and 3 vol.-% BD200 (Sun Fine Chemicals, Korea) as fluorescent blue emitter dopant were deposited on the EBL, to form a blue-emitting first emission layer (EML) with a thickness of 20 nm.
[0258] Then a hole blocking layer was 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 EML.
[0259] Then the electron transporting layer having a thickness of 31 nm was 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.-% of LiQ.
[0260] Then Ag:Mg (90:10 vol.-%) was evaporated at a rate of 0.01 to 1 /s at 10-7 mbar to form a cathode layer with a thickness of 13 nm on the electron transporting layer.
[0261] Then, K1 was deposited on the cathode layer to form a capping layer with a thickness of 75 nm.
[0262] 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.
General Method for Preparation of the Ink Formulation
[0263] To prepare the ink formulation, under inert atmosphere the compounds were weighed into vials. Then, the solvent was added. The mixture was stirred at 60 C. for 10 min. After cooling to room temperature, an aliquot of benzonitrile solutions was added to the anisole solution to obtain a solution with a ratio of 5:1 of anisole to benzonitrile solution. The resulting solution was stirred again for at least 10 min at room temperature. The resulting ink formulation had a solid content of 3 wt.-%.
Ink Formulation for Inventive Example 2-1
[0264] The ink formulation for example 2-1 has the following composition: 10 wt.-%_MC-2:K1 in anisole:benzonitrile (5:1).
[0265] To prepare the ink, solutions of 15 mg MC-2 in 0.8 ml benzonitrile and 139 mg K1 in 4.2 ml anisole were prepared as described above. 0.8 ml benzonitrile solution was added to the anisole solution and stirred as described above.
Ink Formulation for Inventive Example 2-2
[0266] The ink formulation for example 2-2 has the following composition: 10 wt.-%_MC-3:K1 in anisole:benzonitrile (5:1).
[0267] To prepare the ink, solutions of 15 mg MC-3 in 0.8 ml benzonitrile and 139 mg K1 in 4.2 ml anisole were prepared as described above. 0.8 ml benzonitrile solution was added to the anisole solution and stirred as described above.
General Procedure for Fabrication of Electronic Devices Comprising a Hole Injection Layer Comprising a Metal Complex and a Matrix Compound Wherein the Hole Injection Layer is Deposited from Solution
[0268] For bottom emission OLEDs, see Examples 2-1 and 2-2 in Table 3, a 15 /cm.sup.2 glass substrate with 90 nm ITO (available from Corning Co.) with the dimensions 150 mm150 mm0.7 mm was ultrasonically washed with isopropyl alcohol for 5 minutes and then with pure water for 5 minutes and dried at elevated temperature.
[0269] To form the hole injection layer having a thickness of 45 nm on the anode layer, the substrate is placed on a spin-coater with ITO side facing upwards and fixed with vacuum. 5 ml of ink formulation is applied with a syringe with filter (PTFE-0.45 m) on the substrate. Spin-coating parameter are 850 rpm (3 sec ramp-up from zero to maximum speed) for 30 sec. The resulting film is dried at 60 C. for 1 minute on a hotplate. Next step is the cleaning of the substrate around the active area (to ensure a good encapsulation process after evaporation). An additional bake-out at 100 C. for 10 minutes on a hotplate is done. The composition of the hole injection layer can be seen in Table 3. The formulae of the metal complexes can be seen in Table 1.
[0270] Then, the substrate is transferred to a vacuum chamber.
[0271] 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 89 nm.
[0272] Then N,N-di([1,1-biphenyl]-4-yl)-3-(9H-carbazol-9-yl)-[1,1-biphenyl]-4-amine (CAS 1464822-27-2) was vacuum deposited on the HTL, to form an electron blocking layer (EBL) having a thickness of 5 nm.
[0273] 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 emission layer (EML) with a thickness of 20 nm.
[0274] Then a 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.
[0275] Then, the electron transporting layer having a thickness of 31 nm is formed on the hole blocking layer by depositing 4-(4-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl) naphthalen-1-yl)-[1,1-biphenyl]-4-carbonitrile and LiQ in a ratio of 50:50 vol.-%.
[0276] Then, an electron injection layer is formed having a thickness of 2 nm by depositing Yb onto the electron transport layer.
[0277] Then, Al is evaporated at a rate of 0.01 to 1 /s at 10-7 mbar to form a cathode layer with a thickness of 100 nm onto the electron injection layer.
[0278] 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.
[0279] 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/m2 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/cm.sup.2 is determined by interpolating the luminance-voltage and current-voltage characteristics, respectively.
[0280] In bottom emission devices, the emission is predominately Lambertian and quantified in percent external quantum efficiency (EQE). The light is emitted through the anode layer. To determine the efficiency EQE in % the light output of the device is measured using a calibrated photodiode at 10 mA/cm.sup.2.
[0281] In top emission devices, the emission is forward directed through the cathode layer, 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/cm.sup.2.
[0282] 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.
[0283] 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.
[0284] To determine the voltage stability over time U(100 h)(1 h), a current density of at 30 mA/cm.sup.2 was applied to the device. The operating voltage was measured after 1 hour and after 100 hours, followed by calculation of the voltage stability for the time period of 1 hour to 100 hours. A low value for U(100 h)(1 h) denotes a low increase in operating voltage over time and thereby improved voltage stability.
Technical Effect of the Invention
[0285] In Table 2 are shown data for top emission organic electronic devices fabricated by co-deposition from vacuum of metal complex and compound of formula (II).
[0286] In comparative examples 1-1 to 1-4, two metal complexes known in the art are tested at two different doping concentrations.
[0287] As can be seen in Table 2, in comparative examples 1-1 to 1-4 the operating voltage is between 3.67 and 3.78 V, the external quantum efficiency EQE is between 12.9 and 13.91% and the voltage stability over time is between 0.85 and 1.28 V.
[0288] In inventive example 1-1, the semiconductor layer comprises metal complex of formula (I) MC-1. MC-1 comprises a group R.sup.2 selected from CN. As can be seen in Table 2, the EQE is improved to 14.32% and operating voltage stability over time is improved to 0.46 V.
[0289] In inventive examples 1-2, the semiconductor layer comprises 15 vol.-% MC-1. As can be seen in Table 2, EQE and operating voltage stability over time remain improved over comparative examples 1-1 to 1-4.
[0290] In inventive examples 1-3 to 1-25, the semiconductor layer comprises metal complex of formula (1) at a range of doping concentrations and compounds of formula (II) with a range of HOMO levels. As can be seen in Table 2, EQE and operating voltage stability over time are improved over comparative examples 1-1 to 1-4.
[0291] In Table 3 are shown data for bottom emission organic electronic devices fabricated by co-deposition from solution of metal complex of formula (I) and compound of formula (II).
[0292] As can be seen in Table 3, good performance of organic electronic devices is obtained.
[0293] A high efficiency and/or improved operating voltage stability over time are important for the performance and long-term stability of organic electronic devices.
TABLE-US-00002 TABLE 2 Performance of an organic electronic device comprising a metal complex prepared via vacuum thermal evaporation Percentage metal HOMO level Percentage compound U(100 h) complex in of compound of formula (II) in U at 10 EQE at 10 U(1 h) Metal semiconductor Compound of of formula (II) semiconductor layer mA/cm.sup.2 mA/cm.sup.2 (30 mA/cm.sup.2) complex layer [vol.-%] formula (II) [eV] [vol.-%] [V] [%] [V] Comparative CC-1 5 K1 4.68 95 3.67 12.99 0.85 example 1-1 Comparative CC-2 6 K1 4.68 94 3.8 13.91 1.24 example 1-2 Comparative CC-1 9 K1 4.68 91 3.65 12.90 0.89 example 1-3 Comparative CC-2 10 K1 4.68 90 3.78 13.81 1.28 example 1-4 Inventive MC-1 10 K1 4.68 90 3.75 14.32 0.46 example 1-1 Inventive MC-1 15 K1 4.68 85 3.73 14.36 0.47 example 1-2 Inventive MC-1 18 K16 4.73 82 3.81 15.42 0.07 example 1-3 Inventive MC-1 22 K16 4.73 78 3.8 15.44 0.06 example 1-4 Inventive MC-1 15 K2 4.85 85 3.75 14.73 0.06 example 1-5 Inventive MC-1 21 K2 4.85 79 3.74 14.72 0.03 example 1-6 Inventive MC-1 25 K2 4.85 75 3.73 14.71 0.02 example 1-7 Inventive MC-5 1 K16 4.73 99 3.90 15.35 0.18 example 1-8 Inventive MC-5 2 K16 4.73 98 3.84 15.47 0.10 example 1-9 Inventive MC-5 4 K16 4.73 96 3.82 15.41 0.06 example 1-10 Inventive MC-5 6 K16 4.73 94 3.80 15.41 0.05 example 1-11 Inventive MC-5 9 K16 4.73 91 3.78 15.57 0.06 example 1-12 Inventive MC-5 10 K16 4.73 90 3.78 15.57 0.08 example 1-13 Inventive MC-5 11 K16 4.73 89 3.79 15.59 0.05 example 1-14 Inventive MC-5 14 K16 4.73 86 3.78 15.51 0.05 example 1-15 Inventive MC-5 16 K16 4.73 84 3.78 15.66 0.07 example 1-16 Inventive MC-5 20 K16 4.73 80 3.78 15.54 0.07 example 1-17 Inventive MC-5 12 K7 4.84 88 3.81 14.01 0.15 example 1-18 Inventive MC-5 14 K7 4.84 86 3.80 14.03 0.11 example 1-19 Inventive MC-5 16 K7 4.84 84 3.79 14.04 0.08 example 1-20 Inventive MC-5 8 K2 4.85 82 3.74 14.80 0.09 example 1-21 Inventive MC-5 10 K2 4.85 90 3.73 14.85 0.16 example 1-22 Inventive MC-5 12 K2 4.85 88 3.72 14.80 0.05 example 1-23 Inventive MC-5 15 K2 4.85 85 3.71 14.89 0.04 example 1-24 Inventive MC-5 19 K2 4.85 81 3.71 14.86 0.03 example 1-25
TABLE-US-00003 TABLE 3 Performance of an organic electronic device comprising a metal complex prepared via deposition from solution Percentage metal Percentage compound complex in of formula (II) in U at 10 EQE at 10 Metal semiconductor layer Compound of semiconductor layer mA/cm.sup.2 mA/cm.sup.2 complex [vol.-%] formula (II) [vol.-%] [V] [%] Inventive MC-2 10 K1 90 3.83 13.06 example 2-1 Inventive MC-3 10 K1 90 3.85 13.41 example 2-2
[0294] 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.