DE10317556B4 - Mixtures of organic semiconductors capable of emission and matrix materials, their use and electronic components containing them - Google Patents

Abstract

Mixtures containing at least one matrix material A according to formula (1), formula (2), formula (3), formula (10) or formula (11), which A has a glass transition temperature Tg (measured as pure substance) greater than 70 ° C, wherein the symbols and indices have the following meanings: X is O; Y is N; Z is identically or differently on each occurrence CR1 or N, R1, R2, R3 is identically or differently on each occurrence a straight-chain or branched or cyclic alkyl or alkoxy group with 1 up to 40 carbon atoms, where one or more non-adjacent CH2 groups can be replaced by -O-, -S-, -NR5- or -CONR6- and where one or more H atoms can be replaced by F, or one Aryl or heteroaryl group with 1 to 40 carbon atoms, where one or more H atoms can be replaced by F, Cl, Br, I and which can be substituted by one or more non-aromatic radicals R1; R5, R6 are identical or different on each occurrence, H or an aliphatic or aromatic hydrocarbon radical t with 1 to 20 carbon atoms; and at least one emission material B capable of emission, which is a compound which emits light when suitably excited and contains at least one atom from the group consisting of iridium or platinum.

Description

The present invention describes new material mixtures and organic electronic components such as electroluminescent elements containing these mixtures.

In a number of different applications that can be assigned to the electronics industry in the broadest sense, the use of organic semiconductors as active components (= functional materials) has been a reality for some time or is expected in the near future.

Light-sensitive organic materials (e.g. phthalocyanines) and organic charge transport materials (usually hole transporters based on triarylamines) have been used in copiers for a number of years.

1. 1. weiße oder farbige Hinterleuchtungen für monochrome oder mehrfarbige Anzeigeelemente (wie z.B. im Taschenrechner, Mobiltelefone und andere tragbare Anwendungen),
2. 2. großflächige Anzeigen (wie z.B. Verkehrsschilder, Plakate und andere Anwendungen),
3. 3. Beleuchtungselemente in allen Farben und Formen,
4. 4. monochrome oder vollfarbige Passiv-Matrix-Displays für tragbare Anwendungen (wie z.B. Mobiltelefone, PDAs, Camcorder und andere Anwendungen),
5. 5. vollfarbige großflächigen hochauflösenden Aktiv-Matrix-Displays für verschiedenste Anwendungen (wie z.B. Mobiltelefone, PDAs, Laptops, Fernseher und andere Anwendungen).

The use of special semiconducting organic compounds, some of which are also capable of emitting light in the visible spectral range, is just beginning to be introduced to the market, for example in organic electroluminescent devices. Their individual components, the organic light-emitting diodes (OLEDs), have a very wide range of applications as:

1. 1. white or colored backlighting for monochrome or multi-colored display elements (e.g. in pocket calculators, mobile phones and other portable applications),
2. 2. large-area advertisements (such as traffic signs, posters and other applications),
3. 3. lighting elements in all colors and shapes,
4. 4. monochrome or full-color passive matrix displays for portable applications (such as cell phones, PDAs, camcorders and other applications),
5. 5. Full-color, large-area, high-resolution active matrix displays for a wide variety of applications (such as cell phones, PDAs, laptops, televisions and other applications).

In some cases, the development of these applications is already very far advanced, but there is still a great need for technical improvements.

1. 1. So ist v. a. die OPERATIVE LEBENSDAUER von OLEDs immer noch gering, so daß bis dato nur einfache Anwendungen kommerziell realisiert werden können.
2. 2. Die Effizienzen von OLEDs sind zwar akzeptabel, aber auch hier sind - gerade für tragbare Anwendungen („portable applications“) - immer noch Verbesserungen erwünscht.
3. 3. Die Farbkoordinaten von OLEDs, speziell im Roten, sind nicht gut genug. Besonders die Kombination von guten Farbkoordinaten mit hoher Effizienz muß noch verbessert werden.
4. 4. Die Alterungsprozesse gehen i. d. R. mit einem Anstieg der Spannung einher. Dieser Effekt macht spannungsgetriebene organische Elektrolumineszenzvorrichtungen, z.B. Displays oder Anzeige-Elemente, schwierig bzw. unmöglich. Eine stromgetriebene Ansteuerung ist aber gerade in diesem Fall aufwendiger und teurer.
5. 5. Die benötigte Betriebsspannung ist gerade bei effizienten phosphoreszierenden OLEDs recht hoch und muß daher verringert werden, um die Leistungseffizienz zu verbessern. Das ist gerade für tragbare Anwendungen von großer Bedeutung.
6. 6. Der benötigte Betriebsstrom ist ebenfalls in den letzten Jahren verringert worden, muß aber noch weiter verringert werden, um die Leistungseffizienz zu verbessern. Das ist gerade für tragbare Anwendungen besonders wichtig.

The market introduction of simpler devices containing OLEDs has already taken place, as the car radios available on the market from Pioneer or a digital camera from Kodak with an “organic display” demonstrate. However, there are still significant issues that need urgent improvement:

1. 1. Above all, the OPERATING LIFE OF OLEDs is still short, so that up to now only simple applications can be realized commercially.
2. 2. The efficiencies of OLEDs are acceptable, but here too - especially for portable applications - improvements are still desired.
3. 3. The color coordinates of OLEDs, especially in red, are not good enough. In particular, the combination of good color coordinates with high efficiency still needs to be improved.
4. 4. The aging processes usually go hand in hand with an increase in tension. This effect makes voltage-driven organic electroluminescent devices, for example displays or display elements, difficult or impossible. In this case, however, a current-driven control is more complex and expensive.
5. 5. The required operating voltage is quite high, especially in the case of efficient phosphorescent OLEDs, and must therefore be reduced in order to improve the power efficiency. This is particularly important for portable applications.
6. 6. The required operating current has also been reduced in recent years, but it has to be further reduced in order to improve the power efficiency. This is particularly important for portable applications.

The reasons mentioned above under 1. to 6. make improvements in the production of OLEDs necessary.

One development in this regard that has emerged in recent years is the use of organometallic complexes that show phosphorescence instead of fluorescence [MA Baldo, S. Lamansky, PE Burrows, ME Thompson, SR Forrest, Applied Physics Letters, 1999, 75, 4 -6].

For quantum mechanical reasons, up to four times the quantum, energy and power efficiency is possible using organometallic compounds. Whether this new development will prevail depends on the one hand on whether corresponding device compositions can be found that can also implement these advantages (triplet emission = phosphorescence versus singlet emission = fluorescence) in OLEDs. The essential conditions for practical use here are, in particular, a long operating life, high stability against thermal stress and a low operating and operating voltage in order to enable mobile applications.

The general structure of organic electroluminescent devices is for example in U.S. 4,539,507 A and U.S. 5,151,629 A , as EP 1 202 358 A2 described.

1. 1. Eine Trägerplatte = Substrat (üblicherweise Glas oder Kunststofffolien).
2. 2. Eine Transparente Anode (üblicherweise Indium-Zinn-Oxid, ITO).
3. 3. Eine Lochinjektions-Schicht (Hole Injection Layer = HIL): z. B. auf der Basis von Kupfer-phthalocyanin (CuPc), leitfähigen Polymeren, wie Polyanilin (PANI) oder Polythiophen-Derivaten (wie PEDOT).
4. 4. Eine oder mehrere Lochtransport-Schichten (Hole Transport Layer = HTL):
   • üblicherweise auf der Basis von Triarylamin-Derivaten z.B. 4,4',4"-Tris(N-1-naphthyl)N-phenyl-amino)-triphenylamin (NaphDATA) als erste Schicht und N,N'-Di(naphthalin-1-yl)-N,N'-diphenyl-benzidin (NPB) als zweite Lochtransportschicht.
5. 5. Eine oder mehrere Emissions-Schichten (Emission Layer = EML): diese Schicht (bzw. Schichten) kann teilweise mit den Schichten 4 bis 8 zusammenfallen, besteht aber üblicherweise aus mit Fluoreszenzfarbstoffen, z.B. N,N'-Diphenylquinacridone (QA), oder Phosphoreszenzfarbstoffen, z.B. Tris-(2-phenyl-pyridyl)-iridium (Ir(PPy)₃) oder Tris-(2-benzothiophenyl-pyridyl)-iridium (Ir(BTP)₃), dotierten Matrixmaterialien, wie 4,4'-Bis(carbazol-9-yl)-biphenyl (CBP). Die Emissions-Schicht kann aber auch aus Polymeren, Mischungen von Polymeren, Mischungen von Polymeren und niedermolekularen Verbindungen oder Mischungen verschiedener niedermolekularer Verbindungen bestehen.
6. 6. Eine Loch-Blockier-Schicht (Hole-Blocking-Layer = HBL): diese Schicht kann teilweise mit den Schichten 7 und 8 zusammenfallen. Sie besteht üblicherweise aus BCP (2,9-Dimethyl-4,7-diphenyl-1,10-phenanthrolin = Bathocuproin) oder Bis-(2-methyl-8-quinolinolato)-4-(phenyl-phenolato)-aluminium-(III) (BAIq).
7. 7. Eine Elektronentransport-Schicht (Electron Transport Layer = ETL): größtenteils auf Basis von Aluminium-tris-8-hydroxy-chinoxalinat (AlQ₃).
8. 8. Eine Elektroneninjektions-Schicht (Electron Injection Layer = EIL): diese Schicht kann teilweise mit Schicht 4, 5, 6 und 7 zusammenfallen bzw. es wird ein kleiner Teil der Kathode speziell behandelt bzw. speziell abgeschieden.
9. 9. Eine weitere Elektroneninjektions-Schicht (Electron Injection Layer = EIL): ein dünne Schicht bestehend aus einem Material mit einer hohen Dielektrizitätskonstanten, wie z.B. LiF, Li₂O, BaF₂, MgO, NaF.
10. 10. Eine Kathode: hier werden in der Regel Metalle, Metallkombinationen oder Metalllegierungen mit niedriger Austrittsarbeit verwendet, so z. B. Ca, Ba, Cs, Mg, Al, In, Mg/Ag.

An organic electroluminescent device usually consists of several layers which are applied to one another by means of vacuum methods or different printing methods. These layers are in detail:

1. 1. A carrier plate = substrate (usually glass or plastic film).
2. 2. A transparent anode (usually indium tin oxide, ITO).
3. 3. A Hole Injection Layer (HIL): e.g. B. based on copper phthalocyanine (CuPc), conductive polymers such as polyaniline (PANI) or polythiophene derivatives (such as PEDOT).
4. 4. One or more hole transport layers (Hole Transport Layer = HTL):
   • usually based on triarylamine derivatives, for example 4,4 ', 4 "-Tris (N-1-naphthyl) N-phenyl-amino) -triphenylamine (NaphDATA) as the first layer and N, N'-di (naphthalene-1 -yl) -N, N'-diphenylbenzidine (NPB) as the second hole transport layer.
5. 5. One or more emission layers (Emission Layer = EML): this layer (or layers) can partially coincide with layers 4 to 8, but usually consists of fluorescent dyes, e.g. N, N'-diphenylquinacridones (QA), or phosphorescent dyes, e.g. tris- (2-phenyl-pyridyl) -iridium (Ir (PPy) ₃ ) or tris- (2-benzothiophenyl-pyridyl) -iridium (Ir (BTP) ₃ ), doped matrix materials, such as 4,4 ' -Bis (carbazol-9-yl) -biphenyl (CBP). The emission layer can, however, also consist of polymers, mixtures of polymers, mixtures of polymers and low molecular weight compounds or mixtures of different low molecular weight compounds.
6. 6. A hole blocking layer (HBL): this layer can partially coincide with layers 7 and 8. It usually consists of BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline = bathocuproin) or bis- (2-methyl-8-quinolinolato) -4- (phenyl-phenolato) -aluminium- ( III) (BAIq).
7. 7. An electron transport layer (Electron Transport Layer = ETL): largely based on aluminum tris-8-hydroxy-quinoxalinate (AlQ ₃ ).
8. 8. An electron injection layer (EIL): this layer can partially coincide with layers 4, 5, 6 and 7 or a small part of the cathode is specially treated or specially deposited.
9. 9. Another electron injection layer (Electron Injection Layer = EIL): a thin layer consisting of a material with a high dielectric constant, such as LiF, Li ₂ O, BaF ₂ , MgO, NaF.
10. 10. A cathode: metals, metal combinations or metal alloys with a low work function are usually used here, e.g. B. Ca, Ba, Cs, Mg, Al, In, Mg / Ag.

This entire device is structured, contacted and finally also hermetically sealed accordingly (depending on the application), since the service life of such devices is drastically shortened in the presence of water and / or air. The same also applies to so-called inverted structures in which the light is coupled out of the cathode. In these inverted OLEDs, the anode consists e.g. of Al / Ni / NiOx or Al / Pt / PtOx or other metal / metal oxide combinations that have a HOMO greater than 5 eV. The cathode consists of the same materials that are described in points 9 and 10, with the difference that the metal such as Ca, Ba, Mg, Al, In etc. is very thin and therefore transparent. The layer thickness is less than 50 nm, better under 30 nm, even better under 10 nm. Another transparent material can be applied to this transparent cathode, e.g. ITO (indium tin oxide), IZO (indium zinc oxide), etc. ..

Organic electroluminescent devices in which the emission layer (EML) consists of more than one substance have been known for a long time.

In the above-mentioned structure, the matrix material of the emission layer (EML) plays a special role. The matrix material must enable or improve the charge transport of holes and electrons and / or enable or improve the charge carrier recombination and, if necessary, transfer the energy resulting from the recombination to the emitter.

In the case of electroluminescent devices based on phosphorescent emitters, this task has so far been taken over by matrix materials which contain carbazole units.

Matrix materials containing carbazole units, such as the commonly used 4,4'-bis- (N-carbazol-yl) -biphenyl (CBP), however, have some disadvantages in practice. These can be seen, among other things, in the often short to very short service life of the devices manufactured with them and the frequently high operating voltages that lead to low power efficiencies. Furthermore, it has been shown that, for reasons of energy, CBP is unsuitable for blue-emitting electroluminescent devices, which results in poor efficiency.

Out WO 2004/013080 A1 Spirobifluorene derivatives with ketone substituents are known. Mixtures with iridium or platinum compounds are not disclosed.

US 2001/0 053 462 A1 discloses light-emitting devices containing iridium or platinum complexes, diphenylquinone derivatives being used as matrix material. Ketone matrix materials in which the carbonyl function is not bound in a cyclic structure are not disclosed.

It has now surprisingly been found that the use of certain matrix materials in combination with certain emitters lead to significant improvements over the prior art, in particular with regard to efficiency and in combination with a greatly increased service life.

The present invention relates to a mixture containing the matrix materials and phosphorescent emitters described below, as well as OLEDs containing this mixture.

The use of analogous materials in simple devices, as emission materials themselves or as materials in the emission layer in combination with fluorescent emitters has already been described in isolated cases in the literature (see, for example: JP H06 - 192 654 A ), but the characteristics achieved with it, especially the efficiencies and operating voltages, are unsatisfactory.

• - mindestens ein Matrixmaterial A gemäß Formel (1), Formel (2), Formel (3), Formel (10) oder Formel (11), welches eine Glastemperatur (gemessen als Reinsubstanz) größer 70 °C aufweist,

wobei die Symbole und Indizes folgende Bedeutung haben:

X

ist O;

Y

ist N;

Z

ist gleich oder verschieden bei jedem Auftreten CR¹ oder N,

R1, R2, R3

ist gleich oder verschieden bei jedem Auftreten eine geradkettige oder verzweigte oder cyclische Alkyl- oder Alkoxygruppe mit 1 bis 40 C-Atomen, wobei ein oder mehrere nicht benachbarte CH₂-Gruppen durch -O-, -S-, -NR⁵- oder -CONR⁶- ersetzt sein können und wobei ein oder mehrere H-Atome durch F ersetzt sein können, oder eine Aryl- oder Heteroarylgruppe mit 1 bis 40 C-Atomen, wobei ein oder mehrere H-Atome durch F, Cl, Br, I ersetzt sein können und die durch einen oder mehrere, nicht aromatische Reste R¹ substituiert sein kann;

R5, R6

sind gleich oder verschieden bei jedem Auftreten, H oder ein aliphatischer oder aromatischer Kohlenwasserstoffrest mit 1 bis 20 C-Atomen; und

• - mindestens ein zur Emission befähigtes Emissionsmaterial B welches eine Verbindung ist die bei geeigneter Anregung Licht emittiert und mindestens ein Element aus der Gruppe Iridium oder Platin enthält.

The invention therefore relates to mixtures containing them

• - at least one matrix material A according to formula (1), formula (2), formula (3), formula (10) or formula (11), which has a glass transition temperature (measured as pure substance) greater than 70 ° C,

where the symbols and indices have the following meanings:

X

is O;

Y

is N;

Z

is identically or differently on each occurrence CR ¹ or N,

R1, R2, R3

is, identically or differently on each occurrence, a straight-chain or branched or cyclic alkyl or alkoxy group with 1 to 40 carbon atoms, where one or more non-adjacent CH ₂ groups are replaced by -O-, -S-, -NR ⁵ - or - CONR ⁶ - can be replaced and where one or more H atoms can be replaced by F, or an aryl or heteroaryl group with 1 to 40 C atoms, one or more H atoms being replaced by F, Cl, Br, I can be and which can be substituted by one or more, non-aromatic radicals R ^1;

R5, R6

are, identically or differently on each occurrence, H or an aliphatic or aromatic hydrocarbon radical having 1 to 20 carbon atoms; and

• - At least one emission material B capable of emission, which is a compound that emits light when suitably excited and contains at least one element from the group of iridium or platinum.

wobei die Symbole X, Y, R¹, R², R³, R⁵ und R⁶ die unter den Formeln (1) bis (3) genannten Bedeutungen haben, und

Z

gleich oder verschieden bei jedem Auftreten CR¹ oder N ist, enthalten.

Also described, but not the subject of the invention, are mixtures which contain at least one compound of the formula (4) to (9) as matrix material A,

where the symbols X, Y, R ¹ , R ² , R ³ , R ⁵ and R ^{6 have} the meanings given under the formulas (1) to (3), and

Z

^{CR 1} or N is identical or different on each occurrence.

The preference of the materials of the formula (10) or (11) is based in particular on their high glass transition temperatures. Depending on the substitution pattern, these are typically above 70 ° C and mostly above 100 ° C.

bei denen

Ar

eine Aryl- oder Heteroarylgruppe mit 4 bis 40 C-Atomen, vorzugsweise mit 4 bis 20 C-Atomen, ist, wobei ein oder mehrere H-Atome durch F, Cl, Br, I ersetzt sein können und die durch einen oder mehrere, nicht aromatische Reste R¹ substituiert sein kann, wobei mehrere Substituenten R¹, sowohl am selben Ring als auch an den beiden unterschiedlichen Ringen zusammen wiederum ein weiteres mono- oder polycyclisches, aliphatisches oder aromatisches Ringsystem aufspannen können;

Z

gleich oder verschieden bei jedem Auftreten CR¹ oder N ist,

R1

gleich oder verschieden bei jedem Auftreten H, CN, eine geradkettige oder verzweigte oder cyclische Alkyl- oder Alkoxygruppe mit 1 bis 40 C-Atomen, wobei ein oder mehrere nicht benachbarte CH₂-Gruppen durch -HC=CH-, C=O, C=S, C=Se, C=NR⁴, -O-, -S-, -NR⁵-, oder -CONR⁶ - ersetzt sein können und wobei ein oder mehrere H-Atome durch F, Cl, Br, I ersetzt sein können, oder eine Aryl- oder Heteroarylgruppe mit 1 bis 40 C-Atomen, wobei ein oder mehrere H-Atome durch F, Cl, Br, I ersetzt sein können und die durch einen oder mehrere, nicht aromatische Reste R¹ substituiert sein kann, wobei mehrere Substituenten R¹, sowohl am selben Ring als auch an den beiden unterschiedlichen Ringen zusammen wiederum ein weiteres mono- oder polycyclisches, aliphatisches oder aromatisches Ringsystem aufspannen können;

R4, R5, R6

gleich oder verschieden bei jedem Auftreten, H oder ein aliphatischer oder aromatischer Kohlenwasserstoffrest mit 1 bis 20 C-Atomen,

R7

gleich oder verschieden bei jedem Auftreten einer Aryl- oder Heteroarylgruppe mit 1 bis 40 C-Atomen, wobei ein oder mehrere H-Atome durch F, Cl, Br, I ersetzt sein können und die durch einen oder mehrere, nicht aromatische Reste R¹ substituiert sein kann, wobei mehrere Substituenten R¹, sowohl am selben Ring als auch an den beiden unterschiedlichen Ringen zusammen wiederum ein weiteres mono- oder polycyclisches, aliphatisches oder aromatisches Ringsystem aufspannen können, ist.

The compounds according to formula (10), (11) and (12) are also disclosed,

at them

Ar

is an aryl or heteroaryl group with 4 to 40 C atoms, preferably with 4 to 20 C atoms, it being possible for one or more H atoms to be replaced by F, Cl, Br, I and which can be substituted by one or more, non-aromatic radicals R ¹ , where several substituents R ¹ , both on the same ring and on the two different rings together, can in turn form a further mono- or polycyclic, aliphatic or aromatic ring system;

Z

is identically or differently on each occurrence CR ¹ or N,

R1

identically or differently on each occurrence, H, CN, a straight-chain or branched or cyclic alkyl or alkoxy group with 1 to 40 carbon atoms, where one or more non-adjacent CH ₂ groups are represented by -HC = CH-, C = O, C = S, C = Se, C = NR ⁴ , -O-, -S-, -NR ⁵ -, or -CONR ⁶ - can be replaced and where one or more H atoms are replaced by F, Cl, Br, I can be, or an aryl or heteroaryl group having 1 to 40 carbon atoms, where one or more H atoms can be replaced by F, Cl, Br, I and which can be substituted ^{by one or more non-aromatic radicals R 1} , where several substituents R ¹ , both on the same ring and on the two different rings together, can in turn form a further mono- or polycyclic, aliphatic or aromatic ring system;

R4, R5, R6

identically or differently on each occurrence, H or an aliphatic or aromatic hydrocarbon radical with 1 to 20 carbon atoms,

R7

identically or differently on each occurrence of an aryl or heteroaryl group having 1 to 40 carbon atoms, where one or more H atoms can be replaced by F, Cl, Br, I and which are substituted ^{by one or more non-aromatic radicals R 1} can be, where several substituents R ¹ , both on the same ring and on the two different rings together, can in turn form a further mono- or polycyclic, aliphatic or aromatic ring system.

Beispiel 1 Beispiel 2 Beispiel 3

Beispiel 4 Beispiel 5 Beispiel 6

Beispiel 7 Beispiel 8 Beispiel 11

Beispiel 14 Beispiel 15

Beispiel 17 Beispiel 18 Beispiel 19

Beispiel 20 Beispiel 22

Beispiel 24 Beispiel 25 Beispiel 26

Beispiel 34 The present invention is illustrated in more detail by the following examples of matrix materials A, without wishing to restrict it thereto.

example 1 Example 2 Example 3

Example 4 Example 5 Example 6

Example 7 Example 8 Example 11

Example 14 Example 15

Example 17 Example 18 Example 19

Example 20 Example 22

Example 24 Example 25 Example 26

Example 34

The matrix materials A according to the invention described above - for example according to Example 26 - can be used, for example, as co-monomers for producing corresponding conjugated or partially conjugated polymers or also as the core of dendrimers. The corresponding copolymerization is preferably carried out via the halogen functionality. For example, they can be converted into soluble polyfluorenes (e.g. according to EP 0 842 208 A1 or WO 00/2226 A1 ), Poly-spirobifluorene (e.g. according to EP 0 707 020 A2 or EP 0 894 107 A1 ), Poly-para-phenylene (e.g. according to WO 92/18552 A1 ), Polycarbazoles or polythiophenes (e.g. according to EP 1 028 136 A2 ) are polymerized.

The conjugated or partially conjugated polymers or dendrimers described above which contain one or more structural units of the formula (1) to (3), (10) or (11) can be used as matrix material in organic electroluminescent devices.

Furthermore, the matrix materials A can also be produced by the, for example, o. Reaction types are further functionalized, and thus converted into expanded matrix materials A. Functionalization with aryl boronic acids according to SUZUKI or with amines according to HARTWIG-BUCHWALD should be mentioned here as an example.

In order to be used as functional material, the matrix materials A or their mixtures or the matrix materials A containing polymers or dendrimers, optionally together with the emitters B, by generally known methods familiar to the person skilled in the art, such as vacuum evaporation, evaporation in a carrier gas stream, or from solution by spin coating or with various printing processes (e.g. inkjet printing, off-set printing, LITI printing, etc.), applied to a substrate in the form of a film.

The use of printing processes can have advantages with regard to the scalability of production and also with regard to the setting of mixing ratios in the blend layers used.

The matrix materials described above are used in combination with phosphorescence emitters. The organic electroluminescent devices shown in this way are characterized in that they contain at least one compound as emitter B, which is characterized in that it emits light when suitably excited and also contains at least one atom selected from iridium or platinum.

worin

DCy

eine zyklische Gruppe ist, die mindestens ein Donoratom, bevorzugt Stickstoff oder Phosphor, enthält, über welches die zyklische Gruppe an das Metall gebunden ist, und die wiederum ein oder mehrere Substituenten R⁸ tragen kann. Die Gruppen DCy und CCy sind über eine kovalente Bindung mit einander verbunden;

CCy

eine zyklische Gruppe ist, die ein Kohlenstoffatom enthält, über welches die zyklischen Gruppe an das Metall gebunden ist und die wiederum ein oder mehrere Substituenten R⁸ tragen kann;

R8

gleich oder verschieden und bei jedem Auftreten H, F, Cl, Br, I, NO₂, CN, eine geradkettige oder verzweigte oder cyclische Alkyl- oder Alkoxygruppe mit 1 bis 40 C-Atomen, wobei ein oder mehrere nicht benachbarte CH₂-Gruppen durch C=O, C=S, C=Se, C=NR⁴, -O-, -S-, -NR⁵-, oder -CONR⁶ - ersetzt sein können und wobei ein oder mehrere H-Atome durch F ersetzt sein können, oder eine Aryl- oder Heteroarylgruppe mit 4 bis 14 C-Atomen, die durch einen oder mehrere, nicht aromatische Reste R⁸ substituiert sein kann; wobei mehrere Substituenten R⁸, sowohl am selben Ring als auch an den beiden unterschiedlichen Ringen zusammen wiederum ein weiteres mono- oder polycyclisches Ringsystem aufspannen können; ist,

L

ein zweizähnig, chelatisierender Ligand, bevorzugt ein Di-ketonatligand,

R4, R5, R6

gleich oder verschieden ist und bei jedem Auftreten, H oder ein aliphatischer oder aromatischer Kohlenwasserstoffrest mit 1 bis 20 C-Atomen ist.

Particularly preferred mixtures containing, as emitter B, at least one compound of the formulas (13) to (16),

wherein

DCy

is a cyclic group which contains at least one donor atom, preferably nitrogen or phosphorus, via which the cyclic group is bonded to the metal and which in turn can carry ^{one or more substituents R 8.} The groups DCy and CCy are linked to one another via a covalent bond;

CCy

is a cyclic group which contains a carbon atom via which the cyclic group is bonded to the metal and which in turn can carry ^{one or more substituents R 8;}

R8

identically or differently and on each occurrence H, F, Cl, Br, I, NO ₂ , CN, a straight-chain or branched or cyclic alkyl or alkoxy group having 1 to 40 carbon atoms, with one or more non-adjacent CH ₂ groups can be replaced by C CO, C =S, C ^{CSe, C NRNR 4} , -O-, -S-, -NR ⁵ -, or -CONR ⁶ - and one or more H atoms are replaced by F. can be, or an aryl or heteroaryl group with 4 to 14 carbon atoms, which can be substituted ^{by one or more non-aromatic radicals R 8;} where several substituents R ⁸ , both on the same ring and on the two different rings together, can in turn form a further mono- or polycyclic ring system; is

L.

a bidentate, chelating ligand, preferably a diketonate ligand,

R4, R5, R6

is identical or different and, on each occurrence, is H or an aliphatic or aromatic hydrocarbon radical having 1 to 20 carbon atoms.

Examples of the emitters described above can be found in the following applications ( WO 00/70 655 A2 , WO 01/41 512 A1 , WO 02/02 714 A2 , WO 02/15 645 A1 , EP 1 191 613 A2 , EP 1 191 612 A2 , EP 1 191 614 A2 ) can be removed.

The mixture according to the invention contains between 1 to 99% by weight, preferably 3 to 95% by weight, particularly preferably 5 to 50% by weight, in particular 7 to 20% by weight, of emitter B based on the total mixture of emitter B and matrix material A.

The present invention also relates to organic electroluminescent devices (O-LED) containing the mixture according to the invention of matrix material A and emission material B.

The preferred embodiments of the mixtures according to the invention of matrix material A and emission material B are also given for the organic electroluminescent devices (O-LED) according to the invention. To avoid unnecessary repetitions, we will not list them again at this point.

In the present application text and also in the examples below, only organic light-emitting diodes and the corresponding displays are aimed at.

• : Lebensdauerkurven zu Anwendungsbeispiel 1
• : Elektrolumineszenzspektren zu Anwendungsbeispiel 2
• : Effizienz als Funktion der Helligkeit zu Anwendungsbeispiel 2
• : Lebensdauerkurven zu Anwendungsbeispiel 2

Description of the images:

• : Lifetime curves for application example 1
• : Electroluminescence spectra for application example 2
• : Efficiency as a function of brightness for application example 2
• : Lifetime curves for application example 2

Examples

Synthesis of matrix materials A:

Unless otherwise stated, the following syntheses were carried out under a protective gas atmosphere in dried solvents. The starting materials were obtained from ALDRICH [copper (I) cyanide, acetyl chloride, N-methylpyrolidinone (NMP)]. 2-bromo-9,9'-spiro-bifluoren was according to literature methods Pei, Jian et al., J. Org. Chem., 2002, 67 (14) , 4924-4936.

Example 1: Di (9,9'-spiro-bifluoren-2-yl) ketone

A: 2-cyano-9,9'-spiro-bifluorene

A suspension of 158.1 g (0.4 mol) of 2-bromo-9,9'-spiro-bifluorene and 89.6 g (1 mol) of copper (I) cyanide in 1100 ml of NMP was heated to 160 ° C. for 16 h. After cooling to 30 ° C., 1000 ml of saturated ammonia solution were added and the mixture was stirred for a further 30 minutes. The precipitate was filtered off with suction, three times with 300 ml saturated ammonia solution and then washed three times with 300 ml of water and sucked dry. After the solid had been dissolved in 1000 ml of dichloromethane, the solution was dried over sodium sulfate, filtered off over silica gel and concentrated to dryness. The crude product thus obtained was recrystallized once from dioxane: ethanol (400 ml: 750 ml). After drying the crystals in vacuo at 80 ° C., 81.0 g (237 mmol) corresponding to 59.3% of theory were obtained. ¹ H-NMR (CDC13): δ [ppm] = 7.92 - 7.85 (m, 4 H), 7.66 - 7.65 (m, 1 H), 7.44 - 7.39 (m, 3 H), 7.22 - 7.19 (m, 1 H), 7.15 - 7.11 (m, 2 H), 6.99 - 6.98 (m, 1 H), 6.79 - 6.78 (m, 1 H), 6.69 - 6.67 (m, 2 H).

Di (9,9'-spiro-bifluoren-2-yl) ketone

From a solution of 98.8 g (250 mmol) of 2-bromo-9,9'-spiro-bifluorene and 6 ml of 1,2-dichloroethane in 1000 ml of THF and 7.1 g (290 mmol) of magnesium, the corresponding Grignard- Reagent produced. A solution of 85.4 g (250 mmol) of 2-cyano-9,9'-spirobifluorene in a mixture of 300 ml of THF and 1000 ml of toluene was added dropwise to this Grignad solution at 0-5 ° C. over the course of 15 minutes. The mixture was then refluxed for 6 hours. After cooling, a mixture of 35 ml of 10 N HCl in a mixture of 400 ml of water and 600 ml of ethanol was slowly added dropwise. After 16 hours of stirring at room temperature, the solid was filtered off with suction and washed three times with 200 ml of ethanol. The solid was recrystallized 4 times from NMP (5 ml / g) and then sublimed in a high vacuum (T = 385 ° C., p = 5 × 10 ^-5 mbar). The yield with a purity of> 99.9% according to HPLC was 52.1 g (79 mmol), corresponding to 31.6% of the theory obtained. ¹ H-NMR (CDCIs): δ [ppm] = 7.87-7.85 (m, 1H), 7.83-7.81 (m, 2H), 7.78-7.86 (m, 1H), 7.60-7.58 (m, 1st H), 7.39 - 7.34 (m, 3 H), 7.18 - 7.17 (m, 1 H), 7.16 - 7.13 (m, 1 H), 7.10 - 7.07 (m, 2 H), 6.34 - 6.32 (m, 1 H), 6.70-6.69 (m, 2 H).

Manufacture and characterization of organic electroluminescent devices.

OLEDs were produced according to the general method outlined below. Of course, this had to be adapted in each individual case to the respective circumstances (e.g. layer thickness variation in order to achieve optimum efficiency or color).

1. 1. ITO beschichtetes Substrat: Als Substrat wird bevorzugt mit ITO beschichtetes Glas verwendet, das einen möglichst niedrigen Gehalt bzw. keine ionischen Verunreinigungen enthält, wie z. B. Flachglas von den Firmen Merck-Balzers oder Akaii. Es können aber auch andere mit ITO beschichtete transparente Substrate, wie z.B. flexible Kunststofffolien oder Laminate verwendet werden. Das ITO muß eine möglichst hohe Leitfähigkeit mit einer hoher Transparenz verbinden. ITO-Schichtdicken zwischen 50 und 200 nm haben sich als besonders geeignet herausgestellt. Die ITO Beschichtung muß möglichst flach, bevorzugt mit einer Rauigkeit unter 2 nm, sein. Die Substrate werden zunächst mit einer 4%igen Dekonex-Lösung in entionisierten Wasser vorgereinigt. Danach wird das ITO beschichtete Substrat entweder mindestens 10 Minuten mit Ozon oder einige Minuten mit Sauerstoffplasma behandelt oder kurze Zeit mit einer Exzimer-Lampe bestrahlt.
2. 2. Lochinjektions-Schicht (Hole Injection Layer = HIL): Als HIL wird entweder ein Polymer oder eine niedermolekulare Substanz verwendet. Besonders geeignet sind die Polymere Polyanilin (PANI) oder Polythiophen (PEDOT) und deren Derivate. Es handelt sich meist um 1 bis 5%ige wässrige Dispersionen, welche in dünnen Schichten zwischen 20 und 200 nm, bevorzugt zwischen 40 und 150 nm Schichtdicke auf das ITO-Substrat durch Spincoaten, Inkjet-Drucken oder andere Beschichtungsverfahren aufgebracht werden. Danach werden die mit PEDOT oder PANI beschichteten ITO- Substrate getrocknet. Für die Trocknung bieten sich mehrere Verfahren an. Herkömmlich werden die Filme im Trockenofen 1 bis 10 Minuten zwischen 110 und 200°C bevorzugt zwischen 150 und 180°C getrocknet. Aber auch neuere Trocknungsverfahren wie z.B. Bestrahlung mit IR-(Infrarot)-Licht führen zu sehr guten Resultaten, wobei die Bestrahlungsdauer im allgemeinen weniger als einige Sekunden dauert. Als niedermolekulares Material werden bevorzugt dünne Schichten, zwischen 5 und 30 nm, Kupfer-phthalocyanin (CuPc) verwendet. Herkömmlich wird CuPc in Vakuum-Sublimationsanlagen aufgedampft. Alle HIL müssen nicht nur sehr gut Löcher injizieren, sondern auch sehr gut auf ITO und Glas haften; dies ist sowohl für CuPc als auch für PEDOT und PANI der Fall. Eine besonders niedrige Absorption im sichtbaren Bereich und damit eine hohe Transparenz zeigen PEDOT und PANI, welches eine weitere notwendige Eigenschaft für die HIL ist.
3. 3. Eine oder mehrere Lochtransport-Schichten (Hole Transport Layer = HTL): Bei den meisten OLEDs sind eine oder mehrere HTLs Voraussetzung für eine gute Effizienz und hohe Stabilität. Dabei erreicht man mit einer Kombination von zwei Schichten beispielsweise bestehend aus Triarylaminen wie MTDATA (4,4',4"-Tris(N-3-methyl-phenyl)-N-phenyl-amino)-triphenylamine) oder NaphDATA (4,4',4"-Tris(N-1-naphthyl)-N-phenyl-amino)-triphenylamine) als erste HTL und NPB (N,N'-Di(naphthalin-1-yl)-N,N'-diphenyl-benzidin) oder Spiro-TAD (Tetrakis-2,2',7,7'-diphenylamino-spiro-9'9'-bifluoren) als zweite HTL sehr gute Ergebnisse. MTDATA oder NaphDATA bewirken eine Erhöhung der Effizienz in den meisten OLEDs um ca. 20 - 40%; wegen der höheren Glastemperatur T_g wird NaphData (T_g = 130°C) gegenüber MTDATA (T_g = 100°C) bevorzugt. Als zweite Schicht wird Spiro-TAD (T_g = 130°C) wegen der höheren T_g gegenüber NPB (T_g = 95°C) bevorzugt. MTDATA bzw. NaphDATA haben eine Schichtdicke zwischen 5 und 100 nm, bevorzugt 10 und 60 nm, besonders bevorzugt zwischen 15 und 40 nm. Für dickere Schichten benötigt man etwas höhere Spannungen, um die gleiche Helligkeit zu erreichen; gleichzeitig verringert sich die Anzahl der Defekte. Spiro-TAD bzw. NPB haben eine Schichtdicke zwischen 5 und 150 nm, bevorzugt 10 und 100 nm, besonders bevorzugt zwischen 20 und 60 nm. Mit zunehmender Schichtdicke von NPB und den meisten anderen Triarylaminen benötigt man höhere Spannungen für gleiche Helligkeiten. Die Schichtdicke von Spiro-TAD hat jedoch nur einen geringfügigen Einfluß auf die Strom-Spannung-Elektrolumineszenz-Kennlinien, d.h. die benötigte Spannung, um ein bestimmte Helligkeit zu erreichen, hängt nur geringfügig von der Spiro-TAD Schichtdicke ab. Anstelle von niedermolekularen Triarylaminen können auch hochmolekulare Triarylaminen verwendet werden. Es handelt sich meist um 0.1 bis 30%ige Lösungen, welche in dünnen Schichten zwischen 20 und 500 nm, bevorzugt zwischen 40 und 150 nm Schichtdicke auf das ITO-Substrat oder die HIL (z.B. PEDOT- oder PANI-Schicht) durch Spincoaten, Inkjet-Drucken oder andere Beschichtungsverfahren aufgebracht werden.
4. 4. Emissions-Schicht (Emission Layer = EML): Diese Schicht kann teilweise mit den Schichten 3 und/oder 5 zusammenfallen. Sie besteht z.B. aus einem niedermolekularen Wirtsmaterial und einem niedermolekularen Gastmaterial, dem phosphoreszierenden Dotanden, wie beispielsweise CBP oder eines der oben beschriebenen Matrixmaterialien A als Wirtsmaterial und Ir(PP_Y)₃ als Dotand. Gute Resultate erreicht man bei einer Konzentration von 5 - 30% Ir(PP_Y)₃ in CBP oder eines der oben beschriebenen Matrixmaterialien A bei einer EML- Schichtdicke von 10 - 100 nm bevorzugt 10-50 nm. Anstelle von niedermolekularen Licht emittierenden Verbindungen können auch hochmolekulare Licht emittierenden Verbindungen (Polymere) verwendet werden, wobei eine oder auch beide Komponenten des Wirts-Gast-Systems hochmolekular sein können.
5. 5. Eine Elektronentransport- und Lochblockier-Schicht (Hole Blocking Layer = HBL):
   • Als HBL-Material hat sich besonders BCP (2,9-Dimethyl-4,7-diphenyl-1,10-phenanthrolin = Bathocuproin) oder BAIq als sehr wirkungsvoll gezeigt. Eine dünne Schicht von 3 - 30 nm, bevorzugt 5 - 20 nm erhöht die Effizienz sehr effektiv. Anstelle von niedemolekularen HBLs können auch hochmolekulare HBLs verwendet werden.
6. 6. Elektronentransport-Schicht (Electron Transport Layer = ETL): Als ETL-Materialien sind Metall-hydroxy-chinolate gut geeignet; besonders Aluminium-tris-8-hydroxy-chinolat (Alq₃) hat sich als einer der stabilsten Elektronenleiter herausgestellt. Anstelle von niedemolekularen ETLs können auch hochmolekulare ETLs verwendet werden.
7. 7. Elektroneninjektions-Schicht (Electron Injection Layer = EIL): Eine dünne Schicht mit einer Schichtdicke zwischen 0.2 und 8 nm bevorzugt 0.5 - 5 nm bestehend aus einem Material mit einer hohen Dielektrizitätskonstanten, insbesondere anorganische Fluoride und Oxide wie z.B. LiF, Li₂O, BaF₂, MgO, NaF und weiteren Materialien hat sich als EIL als besonders gut herausgestellt. Speziell in Kombination mit Al führt diese zusätzliche Schicht zu einer deutlichen Verbesserung der Elektroneninjektion, und damit zu verbesserten Resultaten bezüglich Lebensdauer, Quanten- und Leistungseffizienz.
8. 8. Kathode: Hier werden in der Regel Metalle, Metallkombinationen oder Metalllegierungen mit niedriger Austrittsarbeit verwendet so z. B. Ca, Ba, Cs, K, Na, Mg, Al, In, Mg/Ag.
9. 9. a) Herstellung dünner Schichten (2.-8.) niedermolekularer Verbindungen: Alle niedermolekularen Materialien der HIL, HTL, EML, HBL, ETL, EIL und Kathode werden in Vakuum-Sublimationsanlagen bei einem Druck kleiner 10^-5 mbar, bevorzugt kleiner 10^-6 mbar, besonders bevorzugt kleiner 10^-7 mbar aufgedampft. Die Aufdampfraten können zwischen 0.01 und 10nm/s bevorzugt 0.1 und 1nm/s betragen. Neuere Verfahren wie die OPVD (Organic Physical Vapour Deposition) oder LITI (Light Induced Thermal Imaging) sind für die Beschichtung niedermolekularer Materialien ebenso geeignet, so wie weitere Drucktechniken. Für dotierte Schichten hat die OPVP ein großes Potential, weil das Einstellen von beliebigen Mischungsverhältnissen besonders gut gelingt. Ebenfalls lassen sich die Konzentrationen der Dotanden kontinuierlich verändern. Somit sind bei der OPVD die Voraussetzung für die Verbesserung der ElektrolumineszenzVorrichtung optimal. Wie oben beschrieben kann die Herstellung der Vorrichtungen auch durch spezielle Druckverfahren (wie das genannte LITI) durchgeführt werden. Dies hat sowohl Vorteile hinsichtlich der Skalierbarkeit der Fertigung, als auch bezüglich der Einstellung von Mischungsverhältnissen in verwendeten Blend-Schichten. Hierfür ist es aber in aller Regel nötig, entsprechende Schichten (für LITI: Transfer-Schichten) zu präparieren, welche dann erst auf das eigentliche Substrat übertragen werden. b) Herstellung dünner Schichten (2.-6.) hochmolekularer Verbindungen (Polymere): Es handelt sich meist um 0.1 bis 30%ige Lösungen, welche in dünnen Schichten zwischen 10 und 500 nm, bevorzugt zwischen 10 und 80 nm Schichtdicke auf das ITO-Substrat oder darunterliegende Schichten durch Spincoaten, Inkjet-Drucken, LITI oder andere Beschichtungsverfahren und Drucktechniken aufgebracht werden.
10. 10. Verkapselung: Eine effektive Einkapselung der organischen Schichten inklusive der EIL und der Kathode ist für organische Elektrolumineszenzvorrichtungen unerläßlich. Wenn das organische Display auf einem Glassubstrat aufgebaut ist, gibt es mehrere Möglichkeiten. Eine Möglichkeit ist das Verkleben des gesamten Aufbaus mit einer zweiten Glas- oder Metallplatte. Dabei haben sich ZweiKomponenten- oder UV-härtende-Epoxykleber als besonders geeignet erwiesen. Dabei kann die Elektrolumineszenzvorrichtung vollständig oder aber auch nur am Rand verklebt werden. Wird das organische Display nur am Rand verklebt, kann man die Haltbarkeit zusätzlich verbessern, indem man einen sogenannten Getter hinzufügt. Dieser Getter besteht aus einem sehr hygroskopischen Material, insbesondere Metalloxide wie z.B. BaO, CaO usw., welches eindringendes Wasser und Wasserdämpfe bindet. Eine zusätzliche Bindung von Sauerstoff erreicht man mit Gettermaterialien wie z.B. Ca, Ba usw.. Bei flexiblen Substraten ist besonders auf eine hohe Diffusionsbarriere gegenüber Wasser und Sauerstoff zu achten. Hier haben sich insbesondere Laminate aus alternierenden dünnen Kunststoff- und anorganischen Schichten (z.B. SiOx oder SiNx) bewährt.

For example, electroluminescent devices can be represented as follows:

1. 1. ITO-coated substrate: The substrate used is preferably glass coated with ITO, which contains the lowest possible content or no ionic impurities, such as. B. Flat glass from Merck-Balzers or Akaii. However, other transparent substrates coated with ITO, such as flexible plastic films or laminates, can also be used. The ITO must combine the highest possible conductivity with a high level of transparency. ITO layer thicknesses between 50 and 200 nm have proven to be particularly suitable. The ITO coating must be as flat as possible, preferably with a roughness below 2 nm. The substrates are first pre-cleaned with a 4% Dekonex solution in deionized water. The ITO-coated substrate is then either treated with ozone for at least 10 minutes or with oxygen plasma for a few minutes or irradiated for a short time with an excimer lamp.
2. 2. Hole Injection Layer (HIL): Either a polymer or a low molecular weight substance is used as the HIL. The polymers polyaniline (PANI) or polythiophene (PEDOT) and their derivatives are particularly suitable. These are mostly 1 to 5% aqueous dispersions which are applied in thin layers between 20 and 200 nm, preferably between 40 and 150 nm layer thickness on the ITO substrate by spin coating, inkjet printing or other coating processes. The ITO substrates coated with PEDOT or PANI are then dried. Several methods are available for drying. The films are conventionally dried in a drying oven between 110 and 200 ° C., preferably between 150 and 180 ° C., for 1 to 10 minutes. However, more recent drying processes such as irradiation with IR (infrared) light also lead to very good results, the irradiation time generally lasting less than a few seconds. Thin layers, between 5 and 30 nm, copper phthalocyanine (CuPc) are preferably used as the low molecular weight material. Conventionally, CuPc is vapor-deposited in vacuum sublimation systems. All HIL not only have to inject holes very well, they also have to adhere very well to ITO and glass; this is the case for CuPc as well as for PEDOT and PANI. PEDOT and PANI show particularly low absorption in the visible range and thus high transparency, which is another necessary property for HIL.
3. 3. One or more hole transport layers (Hole Transport Layer = HTL): With most OLEDs, one or more HTLs are a prerequisite for good efficiency and high stability. A combination of two layers, for example, consisting of triarylamines such as MTDATA (4,4 ', 4 "-Tris (N-3-methyl-phenyl) -N-phenyl-amino) -triphenylamine) or NaphDATA (4,4', 4" -Tris (N-3-methyl-phenyl) -N-phenyl-amino) -triphenylamine) ', 4 "-Tris (N-1-naphthyl) -N- phenyl-amino) -triphenylamine) as the first HTL and NPB (N, N'-Di (naphthalen-1-yl) -N, N'-diphenyl-benzidine) or Spiro-TAD (Tetrakis-2,2 ', 7, 7'-diphenylamino-spiro-9'9'-bifluoren) as a second HTL very good results. MTDATA or NaphDATA increase the efficiency in most OLEDs by approx. 20 - 40%; Because of the higher glass transition temperature T _g , NaphData (T _g = 130 ° C.) is preferred over MTDATA (T _g = 100 ° C.). As the second layer, Spiro-TAD (T _g = 130 ° C) is preferred because of the higher T _g compared to NPB (T _g = 95 ° C). MTDATA and NaphDATA have a layer thickness between 5 and 100 nm, preferably 10 and 60 nm, particularly preferably between 15 and 40 nm. For thicker layers, somewhat higher voltages are required in order to achieve the same brightness; at the same time, the number of defects is reduced. Spiro-TAD or NPB have a layer thickness between 5 and 150 nm, preferably 10 and 100 nm, particularly preferably between 20 and 60 nm. As the layer thickness of NPB and most other triarylamines increases, higher voltages are required for the same brightness. The layer thickness of Spiro-TAD has only a slight influence on the current-voltage-electroluminescence characteristics, ie the voltage required to achieve a certain brightness depends only slightly on the Spiro-TAD layer thickness. Instead of low molecular weight triarylamines, high molecular weight triarylamines can also be used. These are mostly 0.1 to 30% solutions, which are applied in thin layers between 20 and 500 nm, preferably between 40 and 150 nm layer thickness on the ITO substrate or the HIL (e.g. PEDOT or PANI layer) by spin coating, inkjet -Printing or other coating processes can be applied.
4. 4. Emission Layer (EML): This layer can partially coincide with layers 3 and / or 5. It consists, for example, of a low molecular weight host material and a low molecular weight guest material, the phosphorescent dopant, such as CBP or one of the matrix materials A described above as the host material and Ir (PP _Y ) ₃ as the dopant. Good results are achieved at a concentration of _{5-30% Ir (PP Y} ) ₃ in CBP or one of the matrix materials A described above with an EML layer thickness of 10-100 nm, preferably 10-50 nm High molecular weight light-emitting compounds (polymers) can also be used, it being possible for one or both components of the host-guest system to be of high molecular weight.
5. 5. An electron transport and hole blocking layer (HBL):
   • BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline = bathocuproine) or BAIq have proven to be particularly effective as HBL material. A thin layer of 3 to 30 nm, preferably 5 to 20 nm, increases the efficiency very effectively. Instead of low molecular weight HBLs, high molecular weight HBLs can also be used.
6. 6. Electron Transport Layer (ETL): Metal hydroxyquinolates are well suited as ETL materials; aluminum tris-8-hydroxy-quinolate (Alq ₃ ) in particular has proven to be one of the most stable electron conductors. Instead of low molecular weight ETLs, high molecular weight ETLs can also be used.
7. 7. Electron Injection Layer (EIL): A thin layer with a layer thickness between 0.2 and 8 nm, preferably 0.5-5 nm, consisting of a material with a high dielectric constant, in particular inorganic fluorides and oxides such as LiF, Li ₂ O , BaF ₂ , MgO, NaF and other materials have proven to be particularly good as EIL. Especially in combination with Al, this additional layer leads to a significant improvement in electron injection and thus to improved results in terms of service life, quantum and power efficiency.
8. 8. Cathode: As a rule, metals, metal combinations or metal alloys with a low work function are used here. B. Ca, Ba, Cs, K, Na, Mg, Al, In, Mg / Ag.
9. 9. a) Production of thin layers (2.-8.) Of low molecular weight compounds: All low molecular weight materials of the HIL, HTL, EML, HBL, ETL, EIL and cathode are in vacuum sublimation systems at a pressure of less than 10 ^-5 mbar, preferably smaller 10 ^-6 mbar, particularly preferably less than 10 ^-7 mbar. The vapor deposition rates can be between 0.01 and 10 nm / s, preferably 0.1 and 1 nm / s. Newer processes such as OPVD (Organic Physical Vapor Deposition) or LITI (Light Induced Thermal Imaging) are just as suitable for coating low-molecular materials, as are other printing techniques. The OPVP has great potential for doped layers because any mixing ratio can be set particularly well. The concentrations of the dopants can also be changed continuously. Thus, in the case of the OPVD, the prerequisites for improving the electroluminescent device are optimal. As described above, the devices can also be produced by special printing processes (such as the LITI mentioned). This has advantages both in terms of the scalability of production and in terms of setting mixing ratios in the blend layers used. For this, however, it is usually necessary to have appropriate layers (for LITI: Transfer layers), which are only then transferred to the actual substrate. b) Production of thin layers (2.-6.) of high molecular weight compounds (polymers): These are mostly 0.1 to 30% solutions, which are applied in thin layers between 10 and 500 nm, preferably between 10 and 80 nm, on the ITO -Substrate or underlying layers can be applied by spin coating, inkjet printing, LITI or other coating processes and printing techniques.
10. 10. Encapsulation: An effective encapsulation of the organic layers including the EIL and the cathode is essential for organic electroluminescent devices. If the organic display is built on a glass substrate, there are several options. One possibility is to glue the entire structure to a second glass or metal plate. Two-component or UV-curing epoxy adhesives have proven to be particularly suitable. The electroluminescent device can be glued completely or only at the edge. If the organic display is only glued at the edge, the durability can be further improved by adding a so-called getter. This getter consists of a very hygroscopic material, in particular metal oxides such as BaO, CaO, etc., which binds penetrating water and water vapors. An additional binding of oxygen can be achieved with getter materials such as Ca, Ba, etc. In the case of flexible substrates, particular attention must be paid to a high diffusion barrier to water and oxygen. Laminates made of alternating thin plastic and inorganic layers (eg SiOx or SiNx) have proven particularly useful here.

OLED examples:

In this example, the results of two different OLEDs are compared. The basic structure, such as the materials used, the degree of doping and their layer thicknesses, was identical for the two example experiments for better comparability. Only the host material in the emitter layer was exchanged.

The first example describes a comparison standard according to the prior art, in which the emitter layer consists of the host material CBP and the guest material Ir (PP _Y ) ₃ . Furthermore, an OLED with an emitter layer consisting of the host material di (9,9'-spiro-bifluoren-2-yl) ketone and the guest material Ir (PP _Y ) ₃ (synthesized according to WO 02/60 910 A1 ) described. The second example describes a further comparison between CBP and di (9,9'-spirobifluoren-2-yl) ketone (see Example 1) with the red emitter Ir (BTP) ₃ (synthesized according to WO 02/60 910 A1 ).

Analogous to the above-mentioned general procedure, green and red emitting OLEDs with the following structure were produced: PEDOT 60 nm (centrifuged from water; PEDOT obtained from HC Starck; poly- [3,4-ethylenedioxy-2,5-thiophene] NaphDATA 20 nm (vapor-deposited; NaphDATA obtained from SynTec; 4,4 ', 4 "-Tris (N-1-naphthyl) N-phenyl-amino) -triphenylamine S-TAD 20 nm (vapor-deposited; S-TAD manufactured according to WO 99/12 888 A1 ; 2,2 ', 7,7'-tetrakis (diphenylamino) spirobifluorene)

Emitter layer: CBP 20 nm (vapor-deposited; CBP obtained from ALDRICH and further purified, finally sublimed twice; 4,4'-bis- (N-carbazolyl) biphenyl) (comparison standard)

OR: Di (9,9'-spiro-bi-fluorene-2-yl) ketone 20 nm (vapor-deposited, synthesized and purified according to Example 1) each doped with 10% triplet emitter Ir (PPy) ₃ (vaporized)

OR: Ir (BTP) ₃ (vaporized) Bathocuproine (BCP) 10 nm (evaporated; BCP purchased from ABCR, used as received; 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) AlQ ₃ 10 nm (vapor-deposited: AlQ ₃ obtained from SynTec; Tris (quinoxalinato) aluminim (III)) Baal 3 nm Ba on top of 150 nm Al as cathode

These non-optimized OLEDs were characterized in a standard manner; For this purpose, the electroluminescence spectra, the efficiency (measured in cd / A) as a function of the brightness, calculated from current-voltage-brightness characteristics (IUL characteristics), and the service life were determined.

Application example 1: Ir (PPy) ₃

• Die OLEDs, sowohl der Vergleichsstandard, OLED mit CBP, als auch die OLED mit Di(9,9'-spiro-bifluoren-2-yl)keton als Wirtsmaterial zeigen eine grüne Emission, resultierend aus dem Dotanden Ir(PP_Y)₃.

Electroluminescence spectra:

• The OLEDs, both the comparison standard, OLED with CBP, and the OLED with di (9,9'-spiro-bifluoren-2-yl) ketone as host material show a green emission, resulting from the dopant Ir (PP _Y ) ₃ .

• Für OLEDs hergestellt mit dem Wirtsmaterial CBP erhält man typischerweise eine maximale Effizienz von etwa 25 cd/A und für die Referenzleuchtdichte von 100 cd/m² werden 4.8 V benötigt. Im Gegensatz dazu zeigen OLEDs hergestellt mit dem Wirtsmaterial Di(9,9'-spiro-bifluoren-2-yl)keton eine maximale Effizienz von über 30 cd/A, wobei die benötigte Spannung für die Referenzleuchtdichte von 100 cd/m² sogar auf 4.6 V gesenkt wird.

Efficiency as a function of brightness:

• For OLEDs manufactured with the host material CBP, a maximum efficiency of about 25 cd / A is typically obtained, and 4.8 V are required ^{for the reference luminance of 100 cd / m 2.} In contrast, OLEDs produced with the host material di (9,9'-spiro-bifluoren-2-yl) ketone show a maximum efficiency of over 30 cd / A, the voltage required for the reference luminance of 100 cd / m ² even being shown 4.6 V is lowered.

• zeigt die Lebensdauerkurven. Die beiden Lebensdauerkurven wurden zur besseren Vergleichbarkeit in derselben Abbildung dargestellt. Die Abbildung zeigt den Verlauf der Leuchtdichte, gemessen in cd/m², mit der Zeit. Als Lebensdauer bezeichnet man üblicherweise die Zeit, nach der nur noch 50% der Anfangsleuchtdichte erreicht werden.

Service life comparison:

• shows the service life curves. The two service life curves were shown in the same figure for better comparability. The figure shows the course of the luminance, measured in cd / m ² , over time. The service life is usually the time after which only 50% of the initial luminance is reached.

For CBP as the host material, a service life of approx. 150 hours is obtained with an initial ^{brightness of 1400 cd / m 2} , which corresponds to an accelerated measurement, since the initial brightness is well above the brightness required for typical active-matrix-controlled display applications ( 250 cd / m ² ). For di (9,9'-spiro-bifluoren-2-yl) ketone, with the same initial brightness, a service life of approx. 2000 hours is obtained, which corresponds to an increase in service life of approx. 1300%.

The lifetimes for an initial brightness of 250 cd / m ² can now be calculated from these two measured lifetimes. In the case of the host material CBP, a service life of only 4700 hours is obtained, which is well below the required 10,000 hours for display applications. In contrast, the di (9,9'-spiro-bifluoren-2-yl) ketone has a service life of over 60,000 hours, which clearly exceeds the minimum requirements.

Application example 2: Ir (BTP) ₃

Similar experiments could be carried out with a red triplet emitter Ir (BTP) ₃ .

• Die OLEDs, sowohl der Vergleichsstandard, OLED mit CBP, als auch die OLED mit Di(9,9'-spiro-bifluoren-2-yl)keton als Wirtsmaterial, zeigen eine rote Emission, resultierend aus dem Dotanden Ir(BTP)₃. Die beiden Spektren sind in dargestellt.

Electroluminescence spectra:

• The OLEDs, both the comparison standard, OLED with CBP, and the OLED with di (9,9'-spiro-bifluoren-2-yl) ketone as host material, show a red emission resulting from the dopant Ir (BTP) ₃ . The two spectra are in shown.

• Für OLEDs hergestellt mit dem Wirtsmaterial CBP erhält man typischerweise eine maximale Effizienz von etwa 8 cd/A und für die Referenzleuchtdichte von 100 cd/m² werden 6.2 V benötigt. Im Gegensatz dazu zeigen OLEDs hergestellt mit dem Wirtsmaterial Di(9,9'-spiro-bifluoren-2-yl)keton eine maximale Effizienz von über 11 cd/A, wobei die benötigte Spannung für die Referenzleuchtdichte von 100 cd/m² sogar auf 5.2 V gesenkt wird. Dies ist in dargestellt.

Efficiency as a function of brightness:

• For OLEDs manufactured with the host material CBP, a maximum efficiency of about 8 cd / A is typically obtained, and 6.2 V are required ^{for the reference luminance of 100 cd / m 2.} In contrast to this, OLEDs produced with the host material di (9,9'-spiro-bifluoren-2-yl) ketone show a maximum efficiency of over 11 cd / A, the voltage required for the reference luminance of 100 cd / m ² even being shown 5.2 V is lowered. This is in shown.

• zeigt die Lebensdauerkurven. Die beiden Lebensdauerkurven wurden zur besseren Vergleichbarkeit in derselben Abbildung dargestellt. Die Abbildung zeigt den Verlauf der Leuchtdichte, gemessen in cd/m², mit der Zeit.

Service life comparison:

• shows the service life curves. The two service life curves were shown in the same figure for better comparability. The figure shows the course of the luminance, measured in cd / m ² , over time.

For CBP as the host material, a service life of approx. 53 hours is obtained with an initial brightness of almost 1300 cd / m ² , which in this example also corresponds to an accelerated measurement. For di (9,9'-spiro-bifluoren-2-yl) ketone, with the same initial brightness, a service life of approx. 275 hours is obtained, which corresponds to an increase in service life of around 500%.

The lifetimes for an initial brightness of 250 cd / m ² can now be calculated from these two measured lifetimes. In the case of the host material CBP, a service life of only 1600 hours is obtained, which is well below the required 10000 hours for a display application. In contrast, the di (9,9'-spiro-bifluoren-2-yl) ketone has a service life of over 8200 hours, which is close to the minimum requirement.

Claims (7)

Mixtures containing - at least one matrix material A according to formula (1), formula (2), formula (3), formula (10) or formula (11), which A has a glass transition temperature T _g (measured as pure substance) greater than 70 ° C,

where the symbols and indices have the following meanings: X is O; Y is N; Z is identically or differently on each occurrence CR ¹ or N, R ¹ , R ² , R ³ is identically or differently on each occurrence a straight-chain or branched or cyclic alkyl or alkoxy group with 1 to 40 carbon atoms, where one or more non-adjacent CH ₂ groups can be replaced by -O-, -S-, -NR ⁵ - or -CONR ⁶ - and one or more H atoms can be replaced by F, or an aryl or heteroaryl group with 1 to 40 carbon atoms, with one or more H atoms can be replaced by F, Cl, Br, I and which can be substituted ^{by one or more non-aromatic radicals R 1;} R ⁵ , R ⁶ are, identically or differently on each occurrence, H or an aliphatic or aromatic hydrocarbon radical having 1 to 20 carbon atoms; and - at least one emission material B capable of emission, which is a compound which, when suitably excited, emits light and contains at least one atom from the group consisting of iridium or platinum. Mix according to Claim 1 , characterized in that as emitter B, at least one compound of the formula (13) to (16),

where DCy is a cyclic group which contains at least one donor atom, preferably nitrogen or phosphorus, via which the cyclic group is bonded to the metal and which in turn can carry ^{one or more substituents R 8.} The groups DCy and CCy are linked to one another via a covalent bond; CCy is a cyclic group which contains a carbon atom via which the cyclic group is bonded to the metal and which in turn can carry ^{one or more substituents R 8;} R ^{8 are} identical or different and each occurrence is H, F, Cl, Br, I, NO ₂ , CN, a straight-chain or branched or cyclic alkyl or alkoxy group with 1 to 40 carbon atoms, where one or more non-adjacent CH ₂ -Groups can be replaced by C =O, C =S, C =Se, C =NR ⁴ , -O-, -S-, -NR ⁵ -, or -CONR ⁶ - and where one or L is several H atoms can be replaced by F, or an aryl or heteroaryl group having 4 to 14 carbon atoms, which can be substituted ^{by one or more non-aromatic radicals R 8;} where several substituents R ⁸ , both on the same ring and on the two different rings together, can in turn form a further mono- or polycyclic ring system; is, a bidentate, chelating ligand, preferably a diketonate ligand, R ⁴ , R ⁵ , R ^{6 are} identical or different and each occurrence is H or an aliphatic or aromatic hydrocarbon radical with 1 to 20 carbon atoms is used . Mix according to Claim 1 or 2 , characterized in that the matrix material contains one or more polymers or dendrimers. Mix according to Claim 3 , characterized in that the polymer is conjugated or partially conjugated. Mix according to Claim 3 or 4th , characterized in that the polymer is selected from the group of polyfluorenes, poly-spirobifluorenes, poly-para-phenylenes, polycarbazoles, poly-vinylcarbazoles, polythiophenes or from copolymers which have several of the units mentioned here. Mixture according to one or more of the Claims 1 to 5 , characterized in that the mixture contains between 1 to 99% by weight of emitter B based on the total mixture of emitter B and matrix material A. Electronic component, characterized in that it is an organic light-emitting diode (OLED), containing at least one mixture according to one or more of the Claims 1 to 6th .

Images