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• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/06—Luminescent, e.g. electroluminescent, chemiluminescent materials containing organic luminescent materials
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C13/00—Cyclic hydrocarbons containing rings other than, or in addition to, six-membered aromatic rings
  • C07C13/28—Polycyclic hydrocarbons or acyclic hydrocarbon derivatives thereof
  • C07C13/32—Polycyclic hydrocarbons or acyclic hydrocarbon derivatives thereof with condensed rings
  • C07C13/54—Polycyclic hydrocarbons or acyclic hydrocarbon derivatives thereof with condensed rings with three condensed rings
  • C07C13/547—Polycyclic hydrocarbons or acyclic hydrocarbon derivatives thereof with condensed rings with three condensed rings at least one ring not being six-membered, the other rings being at the most six-membered
  • C07C13/567—Polycyclic hydrocarbons or acyclic hydrocarbon derivatives thereof with condensed rings with three condensed rings at least one ring not being six-membered, the other rings being at the most six-membered with a fluorene or hydrogenated fluorene ring system
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C25/00—Compounds containing at least one halogen atom bound to a six-membered aromatic ring
  • C07C25/18—Polycyclic aromatic halogenated hydrocarbons
  • C07C25/22—Polycyclic aromatic halogenated hydrocarbons with condensed rings
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B33/00—Electroluminescent light sources
  • H05B33/12—Light sources with substantially two-dimensional radiating surfaces
  • H05B33/14—Light sources with substantially two-dimensional radiating surfaces characterised by the chemical or physical composition or the arrangement of the electroluminescent material, or by the simultaneous addition of the electroluminescent material in or onto the light source
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
  • H10K85/60—Organic compounds having low molecular weight
  • H10K85/615—Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
  • H10K85/626—Polycyclic condensed aromatic hydrocarbons, e.g. anthracene containing more than one polycyclic condensed aromatic rings, e.g. bis-anthracene
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K2101/00—Properties of the organic materials covered by group H10K85/00
  • H10K2101/10—Triplet emission
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K50/00—Organic light-emitting devices
  • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
  • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K50/00—Organic light-emitting devices
  • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
  • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
  • H10K50/125—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers specially adapted for multicolour light emission, e.g. for emitting white light
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K50/00—Organic light-emitting devices
  • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
  • H10K50/18—Carrier blocking layers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy
  • Y02E10/549—Organic PV cells
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/917—Electroluminescent

Definitions

• Organic and organometallic compounds are used as functional materials in a number of applications that can be broadly attributed to the electronics industry.
• the market for organic electroluminescent devices (for a general description of the structure, see US Pat. No. 4,539,507 and US Pat. No. 5,151,629) and their individual components, organic light-emitting diodes (OLEDs), has already taken place, as have car radios with an "organic display” from Pioneer or use a digital camera from Kodak. Other such products are about to be launched. Nevertheless, significant improvements are still necessary to make these displays a real competitor to the currently dominant liquid crystal displays (LCD) or to surpass them.
• LCD liquid crystal displays
• organometallic complexes which show phosphorescence instead of fluorescence (M.A. Baldo et al., Appl. Phys. Lett. 1999, 75, 4-6).
• organometallic compounds For theoretical spin-statistical reasons, using organometallic compounds as
• Phosphorescence emitters allow up to four times the energy and power efficiency. In order to improve phosphorescent OLEDs, it is not only important to develop the organometallic compounds themselves, but above all to develop other components that are specifically required for this purpose, such as matrix or hole blocking materials.
• An organic electroluminescent device usually consists of several layers which are applied to one another by means of vacuum methods or different printing techniques.
• these layers are in detail:
• Carrier plate substrate (usually glass or plastic film);
• Transparent anode usually indium tin oxide, ITO
• a matrix material e.g. B. 4,4'-bis (carbazol-9-yl) - biphenyl (CBP) with a phosphorescent dye, e.g. B. tris (phenylpyridyl)
• HBL Hole blocking layer
• BAIq bis (2-methyl-8-hydroxyquinolinato) - (4- phenylphenolato) aluminum
• Electron Transport Layer mostly based on aluminum tris-8-hydroxyquinolinate (AIQ 3 );
• thin layer of a material with a high dielectric constant such as.
• Cathode usually metals, metal combinations or metal alloys with a low work function, e.g. B. Ca, Ba, Mg, Al, In, Mg / Ag, but also organic-inorganic hybrid cathodes. Depending on the device structure, several of these layers can coincide, or each of these layers need not necessarily be present. It is also possible to use thin insulator layers or dielectric layers between two of the active layers.
• the short lifespan poses a problem: Especially for full color applications, it is particularly bad if the individual colors age at different speeds, as is currently the case. This means that there is a significant shift in the white point before the end of the service life (which is usually defined by a drop to 50% of the initial brightness). H. the color fidelity of the display is worse.
• the operating voltage required is quite high, especially in the case of efficient phosphorescent OLEDs, and must therefore be reduced in order to improve the power efficiency. 5.
• the efficiency, in particular the power efficiency (measured in Im / W), of phosphorescent OLEDs is acceptable, but improvements are still desired here as well.
• the structure of the OLEDs is complex and technologically complex due to the large number of organic layers; a reduction in the number of layers is desirable for production in order to reduce the number of production steps, thereby simplifying the technology and increasing production reliability. The reasons mentioned above make improvements in the production of OLEDs necessary.
• HBL hole blocking layer
• BCP bathoproin
• Another hole blocking material is bis (2-methyl-8-hydroxyquinolinato) - (4-phenylphenolato) aluminum (III) (BAIq). This significantly improved the stability and lifespan of the devices, but with the disadvantage that the quantum efficiency of the devices with BAIq is significantly (approx. 40%) lower than with BCP (T. Watanabe et al., Proc. SPIE 2001, 4105, 175). Kwong et al. (Appl. Phys. Lett.
• hole blocking materials used to date lead to unsatisfactory results. There is therefore still a need for hole blocking materials which lead to good efficiencies in OLEDs, but at the same time also have a long service life. It has now surprisingly been found that OLEDs, the specific - listed below - Contain spirobifluorene derivatives as hole blocking materials, have significant improvements over the prior art. With these hole blocking materials, it is possible to obtain high efficiencies and good lifetimes at the same time, which is not possible with materials according to the prior art. It was also found that an electron transport layer does not necessarily have to be used with the new hole blocking materials, which is also a technological advantage.
• EP 00676461 describes the use of spirobifluorene oligophenylene derivatives and other spirobifluorene derivatives in the emitting layer or in a charge transport or injection layer in a fluorescent OLED. However, this document does not show how these compounds could be used to advantage in phosphorescent OLEDs.
• the invention relates to organic electroluminescent devices containing an anode, a cathode and at least one emission layer containing at least one matrix material which is doped with at least one phosphorescent emitter, characterized in that at least one hole-blocking layer is introduced between the emission layer and the cathode, the at least one contains a compound of the formula (1),
• Aryl is the same or different in each occurrence, an aromatic or heteroaromatic ring system with 1 to 40 aromatic C atoms, which can be substituted by one or more radicals R;
• the aryl substituent can be used at any point with the spirobifluorene
• An aromatic or heteroaromatic ring system in the sense of this invention is to be understood as a system which does not necessarily only contain simple aromatic or heteroaromatic groups, but which can also contain oligo- and polycyclic systems and condensed aromatic units and in which also several aromatic or heteroaromatic groups can be interrupted by a short non-aromatic unit, such as sp 3 -hybridized C, O, N, etc.
• a short non-aromatic unit such as sp 3 -hybridized C, O, N, etc.
• systems such as 9,9'-spirobifluorene, 9,9-diarylfluorene, triarylamine, diphenyl ether, etc. should also be understood as aromatic systems.
• the OLED can also contain further layers, such as, for example, hole injection layer, hole transport layer, electron injection layer and / or electron transport layer.
• An insulator layer between two of the active layers can also be useful. However, it should be pointed out that all of these layers do not necessarily have to be present. So good results are still obtained if, for. B. no hole injection layer and / or no hole transport layer and / or no electron transport layer and / or no electron injection layer can be used. It has thus been found that OLEDs according to the invention which contain a hole blocking layer of the formula (1) continue to provide comparably good efficiencies and lifetimes with reduced operating voltage if no electron injection and electron transport layers are used.
• the hole blocking layer according to the invention preferably contains at least 50% of compounds of the formula (1), particularly preferably at least 80%, very particularly preferably consists only of compounds of the formula (1).
• aryl is the same or different in each occurrence, an aromatic or heteroaromatic ring system with 1 to 20 aromatic carbon atoms, which can be substituted by one or more radicals R;
• R 1 is as defined above; n is the same or different at each occurrence 1 or 2; m is the same or different at each occurrence 0, 1 or 2; o is the same or different at each occurrence 2 or 3; p is the same or different at each occurrence 2, 3 or 4; the aryl substituent is preferably linked via the positions
• Organic electroluminescent devices are particularly preferred in which the following applies to compounds of the formula (1):
• Aryl is the same or different in each occurrence, is composed of phenyl and / or pyridine groups, contains a total of 5 to 18 aromatic C atoms and can be substituted by one or more radicals R;
• R 1 is as defined above; n is 1 on each occurrence; m is the same or different at each occurrence 0 or; o is 3 for each occurrence; p is the same or different at each occurrence 3 or 4; the aryl substituent and the substituents R which are not equal to H are preferably linked via position 2 or also via positions 7, 2 'and / or T.
• Compounds according to formula (1) very particularly preferably contain a total of two aryl substituents which are linked to the spirobifluorene unit either via positions 2 and 7 or via positions 2 and 2 ', or they contain a total of four aryl substituents which via the Positions 2, 2 ', 7 and 7' are linked to the spirobifluorene unit.
• the glass transition temperature of the compounds of the formula (1) is preferably> 100 ° C, particularly preferably> 120 ° C, very particularly preferably> 140 ° C. It has been shown that the glass transition temperature of oligoarylene compounds which contain at least one spirobifluorene unit are usually in this range, while the glass transition temperature of simple oligophenylenes is often significantly lower. Without wishing to be bound by any particular theory, this may be caused by the sterically demanding molecular structure. This justifies the preference of these materials over simple oligophenylenes according to the prior art. It has been shown that the best results (in terms of efficiency and service life) are achieved if the layer thickness of the hole blocking layer is 1 to 50 nm, preferably 5 to 30 nm.
• Electroluminescent device which does not contain an electron transport layer and in which the hole blocking layer is directly adjacent to the electron injection layer or the cathode. This is a surprising result, since the same device structure with BCP as hole blocking material without ETL delivers significantly shorter lifetimes.
• the present invention is illustrated by the following examples of hole blocking materials according to formula (1), without wishing to restrict them thereto.
• the person skilled in the art can produce further electroluminescent devices according to the invention with similar hole blocking materials from the description and the examples given without inventive step.
• the matrix for the phosphorescent emitter is preferably selected from the classes of carbazoles, e.g. B. according to WO 00/057676, EP 01/202358 and WO 02/074015, the ketones and imines, e.g. B. according to the unpublished application DE 10317556.3, the phosphine oxides, the phosphine sulfides, the phosphine selenides, the phosphazenes, the sulfones, the sulfoxides, for. B. according to the unpublished application DE 10330761.3, the silanes, the polypodal metal complexes, for. B.
• the phosphorescent emitter is preferably a compound which has at least one element with an atomic number greater than 36 and less than 84.
• the phosphorescent emitter particularly preferably contains at least one element with an atomic number greater than 56 and less than 80, very particularly preferably molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold and / or europium, e.g. B.
• One or more layers are preferably coated in the organic electroluminescent device using a sublimation process.
• the low molecular weight materials are evaporated in vacuum sublimation systems at a pressure ⁇ 10 "5 mbar, preferably ⁇ 10 " 6 mbar, particularly preferably ⁇ 10 "7 mbar.
• One or more layers are likewise preferably coated in the organic electroluminescent device using the OVPD process (Organic Vapor Phase Deposition) or with the aid of carrier gas sublimation.
• OVPD process Organic Vapor Phase Deposition
• the low molecular weight materials are applied at a pressure between 10 "5 mbar and 1 bar.
• one or more layers in the organic electroluminescent device with a printing process, such as.
• a printing process such as.
• LITI Light Induced Thermal Imaging, thermal transfer printing
• InkJet printing inkjet printing
• the operating voltages are lower in devices according to the invention than in devices according to the prior art.
• the layer structure can be simplified because a separate electron transport layer does not necessarily have to be used. This is a surprising result, since the same device structure with BCP instead of compounds according to formula (1) without a separate electron transport layer delivers significantly poorer lifetimes and efficiencies. 5. If no separate electron transport layer is used, there is a further advantage: the operating voltages are much lower here; this increases the performance efficiency considerably. This is a surprising result, since the same device structure with BAIq instead of compounds according to formula (1) results in a hardly reduced operating voltage.
• organic light-emitting diodes and the corresponding displays are aimed at.
• O-SCs organic solar cells
• O-lasers organic laser diodes
• Example 1 Synthesis of 2,7-bis (4-biphenyl-1-yl) -2 ', 7'-di-tert-butyl-spiro-9,9' - bifluorene (HB 1) A degassed suspension of 73.3 g (125 mmol) 2,7-dibromo-2 ', 7'-di-te / t-butyl-9,9'-spirobifluorene, 69.3 g (350 mmol) 4-biphenylboronic acid and 111.5 g (525 mmol) tripotassium phosphate in one Mixture of 700 mL toluene, 100 mL dioxane and 500 mL water was mixed with 2.28 g (7.5 mmol) tris-o-tolylphosphine and then 281 mg (1.25 mmol) of palladium (II) acetate were added.
• HB 1 2,7-bis (4-biphenyl-1-yl
• Example 2 Synthesis of 2-2S7,7'-tetrakis (2-biphenyl-1-yl) spiro-9.9 ' bifluorene (HBM2) A degassed suspension from 158.0 g (80 mmol) 2,2', 7, 7'-tetrabromo-9.9 ' ⁇ spirobifluorene, 75.1 g (379 mmol) 2-biphenylboronic acid and 142.7 g (672 mmol) tripotassium phosphate in a mixture of 400 mL toluene, 50 mL dioxane and 300 mL water was mixed with 2.19 g (7.2 mmol) of tris-o-tolylphosphine and then mixed with 270 mg (1.2 mmol) of palladium (II) acetate. This suspension was heated under reflux for 16 h. The one that failed after cooling to room temperature
• the OLEDs were produced using a general process which was adapted to the particular circumstances in each individual case (e.g. layer thickness variation to optimize efficiency or color).
• a compound of the formula (1) was used as the hole blocking layer and the electron transport layer was optionally omitted.
• Electroluminescent devices according to the invention can be represented as described for example in DE10330761.3. The following examples show the results of various OLEDs, both with hole blocking materials according to formula (1) and with BCP and BAIq as comparison materials.
• the basic structure, the materials used and layer thicknesses (except for the HBLs) were identical for better comparability.
• Phosphorescent OLEDs with the following structure were produced in accordance with the above-mentioned general procedure: PEDOT (HIL) 60 nm (spun on from water; obtained as Baytron P from HC Starck; poly (3,4-ethylenedioxy-2,5-thiophene)) NaphDATA ( HTL) 20 nm (evaporated; obtained from SynTec; 4,4 ', 4 "tris (N-1-naphthyl-N-phenylamino) -triphenylamine)
• HTL S-TAD
• EML tetrakis (diphenylamino) -spirobifluorene)
• HBL matrix material
• AIQ 3 (ETL) not available in all devices (see Table 1); if available: evaporated (obtained from SynTec; Tris (8-hydroxyquinolinato) aluminum (III)) Ba-Al (cathode) 3 nm Ba, then 150 nm AI.
• OLEDs which have not yet been optimized, have been characterized as standard; the electroluminescence spectra, the efficiency (measured in cd / A), the power efficiency (measured in Im / W) depending on the brightness and the service life were determined.
• the lifetime is defined as the time after which the initial brightness of the OLED has dropped by half at a constant current density of 10 mA / cm 2 .
• Table 1 summarizes the results of the OLEDs according to the invention and of some comparative examples (with BCP and BAIq) (Examples 4 and 5). Only the hole blocking layer and the electron conductor layer (composition and layer thickness) are listed in the table. The other layers correspond to the structure mentioned above.
• the OLEDs all show green emission with the CIE color coordinates (0.39; 0.57) resulting from the dopant Ir (PPy) 3 (Table 1, Examples 4 and 5).
• BAIq (example 4c) only achieved 27.3 cd / A or 18.8 Im / W and BCP (example 4d) reached 32.6 cd / A, but only a power efficiency of 18.2 Im / W.
• a similarly good behavior is obtained for OLEDs without AIQ 3 as ETL and with HBM2 as a hole blocking layer, as can be seen from Table 1, Example 5.
• HBM2 you get an efficiency of 31.0 cd / A, with BAIq only 24.8 cd / A and with BCP even only 16.7 cd / A.
• the power efficiency with HBM2 is 18.1 Im / W, in contrast with BAIq only 14.7 Im / W and with BCP only 8.7 Im / W.
• Table 1 shows that HBM1 (Example 4a) with 910 h at 10 mA / cm 2 has the best lifetime, followed by HBM2 with 650 h. OLEDs without AIQ 3 as ETL all have a shorter lifespan, with HBM2 (example 5a) performing best at 580 h. The lifespan is usually the time after which only 50% of the initial luminance is reached. From the measured lifetimes, lifetimes can now be calculated for an initial brightness of 400 cd / m 2 . In the case of HBM1 (example 4a), a service life of over 60,000 h is obtained and with HBM2 (example 5a) over 40,000 h, which is significantly higher than the 10,000 h required for display applications.
• phosphorescent OLEDs which contain hole blocking materials according to formula (1) have high efficiencies with long lifetimes and low operating voltages, as can easily be seen from the examples in Table 1.

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