WO2006069724A1

WO2006069724A1 - Organic electroluminescent component with an increased service life

Info

Publication number: WO2006069724A1
Application number: PCT/EP2005/013834
Authority: WO
Inventors: Jörn POMMEREHNE; Klaus Bonrad; Clemens Ottermann; Marcus Bodesheim; Thomas Frank
Original assignee: Schott Ag
Priority date: 2004-12-22
Filing date: 2005-12-22
Publication date: 2006-07-06
Also published as: DE102004063134A1; DE102004063134B4

Abstract

The aim of the invention is to increase the service life of organic electroluminescent components. According to the invention, an organic electroluminescent component is provided with at least one organic electroluminescent layer, wherein the component contains an (ev) singlet oxygen quenching agent.

Description

Organic electroluminescent device with increased lifetime

Description The invention relates to organic electroluminescent

Components, so-called OLEDs (organic light-emitting diodes), in particular, the invention relates to measures to increase the life of such elements.

OLEDs are increasingly being used for a wide variety of optoelectronic applications. For example, unlike conventional inorganic semiconductor light-emitting diodes, OLEDs can be produced as large-area, thin light-emitting elements with a low operating voltage.

In comparison to the materials of inorganic light-emitting diodes, however, organic compounds are generally more unstable. A problem with OLEDs is therefore still their limited life. The organic substances that are used in an OLED primarily as an electroluminescent functional material, are often reactive and degrade, inter alia, under the influence of oxygen. For many applications where reliability is very important, failures due to aging are

OLEDs still a major impediment to the continued spread of these products.

One way to increase the lifetime of OLEDs is to gas-tightly encapsulate the one or more organic layers. However, oxygen may also penetrate over time. The oxygen can also be incorporated or enclosed in the component during component production. Thus, an inert gas used in the production may be contaminated or the materials used will release oxygen over time. Among other things that is for the

Electrode layers, commonly used indium tin oxide (ITO) have been known to slowly release oxygen, which can degrade the electroluminescent materials of the OLED.

Another possibility is therefore to prevent existing oxygen from reacting with the organic functional materials. For example, the oxygen can be chemically bound with suitable substances, getter materials, scavengers, reducing agents or drying agents, especially for water.

Another possibility is to reduce the reactivity of the oxygen. This can be achieved by quenching oxygen in the singlet state. A special feature of oxygen is that the first two electronically excited molecular states 02 (a ^ -Ag) and O2 (blΣ ⁺ g) are singlet states and the ground state is O2 (X ^ Σ ^~ g)

Triplet state is. The O2 (a ^ Δg) singlet state is metastable due to selection rules with a lifetime, typically from a few microseconds to a few hundred milliseconds, depending on the environment in which it is located. Since most organic functional molecules in the ground state have singlet multiplicity, a reaction of these molecules with ground state oxygen is kinetically inhibited. Owing to the singlet multiplicity and the 94.2 kJ / mol energy content of 02 (a ^ Δg) compared to the ground state, oxygen molecules are in however, this singlet state is a much stronger oxidant than triplet ground state oxygen.

It should be added that there is also another singlet state of the oxygen molecule, the

O2 (bl ⁺ g), which has an energy of 157 kJ / mole above the ground state. However, this state can pass into the 02 (a ^ Δg) in a spin-like manner, so that the

Lifespan of O2 (bLΣ ⁺ g) in solvents, or in the presence of collision partners at best barely more than 100 nanoseconds. Accordingly, this state plays only a minor role in the deactivation of singlet oxygen.

From JP 05-190282 A and JP 05-190283 it is known to use singlet quencher in OLEDs. For example, β-carotene or ethylene compounds, such as tetramethyl ethylene, are to serve as quenchers. The non-radiative deactivation channel of singlet oxygen, which occurs in the quencher molecules described there, in particular in β-carotene, is the spin-allowed energy transfer (ET) to triplet states of the quencher substances acting as acceptor molecules. The necessary condition for deactivation is that the energy of the acceptor triplet be below that of the singlet donor. This deletion or deactivation mechanism is also referred to as so-called "chemical deletion".

Tetramethyl ethylene is also known as a singlet oxygen chemical quencher. However, the singlet oxygen seizes the double bond of the Tetramethyl-ethylene and as a reaction product, a hydroperoxide is formed.

Although ß-carotene is known in biology and medicine as an excellent singlet oxygen quencher, when used in OLEDs, however, there are several disadvantages. For example, carotene is an intense dye, which accordingly affects the optical properties of OLEDs. Thus, β-carotene can undesirably alter the spectrum of the emitted light of an OLED. Also, β-carotene and the molecules known in the art which are used as singlet oxygen quencher typically have a large molecular weight. Such large molecules can, however, the electrical properties of the organic

Layers of the OLEDs or their polymerization and / or deposition in the component production adversely affect or even prevent.

The use of chemical quenchers, e.g. Tetramethyl ethylene can also be detrimental because the chemical quenchers can also trigger photochemical reactions and thus alter the organic layers. Moreover, in the chemical deactivation of singlet oxygen, reaction products or other secondary products can form, which in turn are reactive and can then attack the functional molecules of the organic functional layer or, by coloring or other physical properties, the function of the OLED device in a difficult to predict manner can affect negatively.

The invention is therefore based on the object, the life of organic layers of components while avoiding or at least reducing the abovementioned disadvantages of known quenchers for OLEDs.

This object is already achieved in a surprisingly simple manner by the subject matter of the independent claims. Advantageous embodiments and modifications of the invention are the subject of the dependent claims.

Accordingly, the invention provides an organic electroluminescent device having at least one organic electroluminescent layer containing a singlet oxygen (e-v) quenching substance.

Such a component can be produced in a simple manner according to the invention by applying a layer sequence with two electrode layers and at least one electroluminescent layer to a substrate, wherein an (e-v) quenching substance is introduced into the layer sequence or in contact therewith. In particular, an (e v) quenching substance can be introduced into the electroluminescent layer or in direct or indirect contact therewith.

In the simplest case, an OLED typically comprises a functional organic layer with organic electroluminescent molecules embedded between two electrode layers with different work functions. This functional organic layer with organic electroluminescent molecules is referred to in the context of this invention as an electroluminescent layer. In addition to this layer and the electrode layers acting as anode and cathode, it is also possible for further functional layers to be present. For the purposes of this invention, the (ev) quenching substance is understood as meaning a substance with molecules which, owing to their functional group (s), are capable of deactivating or quenching singlet oxygen as a result of resonant energy transfer to vibronic states of the molecules. The electronic excitation energy is converted in the collisions into vibrational energy of the collision partner, that is, the molecules of the (ev) quenching substance. At the same time chemical deactivation occurs if necessary at the same time. The excitation energy of the singlet oxygen is converted accordingly only into thermal energy. A reaction of the quenching substance, which can lead to aggressive reaction products, is inventively avoided. In addition, the (ev) quenching essentially depends on the functional groups of the molecules and hardly on their overall structure. This makes it possible that also easily mentioned molecules with a small molecular weight can be installed, which do not interfere with the electrical properties of the functional layer or at most negligible. The energy transfer can be particularly resonant, that is to take place particularly efficiently in terms of particularly high rate constants, when the energy gaps of the vibrational states of the (ev) - extinguishing substance molecules are adapted to the energy gap between singlet and ground state oxygen as well as possible. This means that it is advantageous if, during a resonant energy transfer, the electronic excitation energy of the singlet oxygen is converted as completely as possible into vibrational energy of the (ev) quenching substance molecules. Any surplus energy amounts are called missing energy. Thus, a particularly efficient, ie resonant erasure of Singlet oxygen instead, when in the energy transfer little lack of energy occurs.

The vibrational energy of the (e-v) quenching substance molecules is a molecular property. In the (e-v) deletion of

Singlet oxygen mainly occupy the terminal molecular groups of an (e-v) quenching substance molecule singlet oxygen electronic energy. These terminal molecule groups are called terminal oscillators for the purposes of the invention.

Thus, advantageously, an (e-v) quenching substance containing molecules having at least one functional group with a terminal oscillator can be used, wherein the terminal oscillator has vibrational energy of the fundamental vibration or an overtone of the stretching vibration equal to that

Energy difference between the O2 (a-1-Δg) and the 02 (X ^ Σ ^~ g) state of molecular oxygen or its vibrational energy from this energy difference by at most 37%, in particular with a

Oscillation quantum number n is less than or equal to 3, preferably deviates by more than 10%. In the range of these energetic deviations, the collision-induced energy transfer from singlet oxygen under excitation of a stretching vibration is particularly probable, so that high rate constants for the resonant (e-v) deactivation can be achieved.

When deactivating with an (e-v) quenching substance, the following reaction takes place:

XY (n = 0) -> XY (n = 1, 2, 3). Here, m denotes the oscillation quantum number of the stretching vibration of the oxygen molecule, n the oscillation quantum number of the stretching vibration of the (ev) quenching substance, and XY a terminal oscillator having atoms X, Y, for example, a hydroxyl group of a molecule. The most effective contribution to the deletion is provided by the transition of oxygen from m = 0 to m = 0. For the purposes of the invention, the (ev) quenching substance is therefore particularly preferably understood to be a quenching substance which contains at least one functional group with a terminal oscillator, wherein the terminal oscillator has a vibrational energy of the fundamental vibration or of an overtone of the stretching vibration which is equal to that of FIG

Energy difference between the 02 (a-LΔg) (m = 0) - and .dem

O2 (X ^ Σ-g) (m = 0) state of molecular oxygen or its vibrational energy of this energy difference by at most 37%, preferably at most 10% deviates.

Particularly suitable for deactivating singlet oxygen are (e-v) quenching substances which contain molecules having at least one hydroxyl group. Particular preference is given to using organic molecules as extinguishing substance (e-v), water not being considered as an organic molecule in this sense. Water is particularly suitable for deactivating singlet oxygen since water molecules are composed solely of OH groups. However, the use of water is only possible where the layers of the organic

Component, including functional layers and electrode layers are not damaged by the water, so that water for organic electroluminescent devices is generally less suitable. The Hydroxyl group with an OH bond as a terminal oscillator is particularly well suited for resonant (ev) quenching, since the stretching vibration energy works well with the

Excitation energy of the O2 (a ^ Δg) state of the oxygen matches.

For example, however, the (e-v) quenching substance may also contain molecules having at least one NH or NH 2 group or a C-H bond. These are somewhat less effective than OH groups, but even with NH or NH 2 groups or C-H bonds in which one NH or CH bond forms one terminal oscillator each, a considerably accelerated quenching of the singlet oxygen can still be achieved become. In particular, it is also contemplated to use molecules containing both N-H and O-H bonds.

An (e-v) quenching substance can protect the organic electroluminescent layer particularly effectively if the (e-v) quenching substance is present in this layer itself. In many cases, it is sufficient if the (e-v) quenching substance is present in a concentration of at most 5 percent by weight of the active electroluminescent substance of the organic electroluminescent layer, preferably at most 1 percent by weight in the organic electroluminescent layer.

However, it may also be advantageous as an alternative or additional measure to accommodate the (ev) quenching substance in a separate constituent of the component, and thus to prevent singlet oxygen arising outside the organic functional layer from penetrating into the layer. This embodiment is possible because the rate constant of the diffusion of Oxygen in the subject components is so high that deactivation of singlet oxygen in these layers can provide efficient protection of the functional layers.

Advantageously, small molecular weight molecules can be used which are easily mobile in the organic electroluminescent layer and / or which do not or only slightly disturb the electronic properties of the layer. Their molecular weight is preferably less than 528 g / mol, preferably in particular less than 374 g / mol and particularly preferably less than 178 g / mol. This means that preference is given to using (e-v) quenching substances which have a limited size or a limited number of atoms in the molecule, so that the negative influences on the organic functional layers, in particular on the electroluminescent layer, can be minimized as far as possible.

But it is also possible to use substances with a large molecular weight as extinguishing substances. Thus, according to another embodiment of the invention, it is provided that the (e-v) quenching substance comprises a polymer having hydroxyl groups or NH or NH 2 groups. This may, for example, form a matrix for the electroluminescent molecules of the organic electroluminescent layer. Also, such a polymer may be used as a constituent of the device adjacent to the electroluminescent layer with a surface so that singlet oxygen can be neutralized at the interface formed thereby.

The selection of the (ev) quenching substance is advantageously also based on the layers of the device and their chemical and electrical properties. Examples of organic substances which may be contained as quencher in an (ev) quenching substance are:

a monohydric or polyhydric alcohol, cyclohexanol,, a carbohydrate, a cellulose derivative, a starch derivative, a glycerol monooleate, an aminoalcohol, a polyamine, a polyamide.

In the selection of the (ev) quenching substance, it may then be considered, for example, whether the substance is miscible with a solvent for producing the organic electroluminescent layer and / or any further functional layers and / or whether the substance contains one or more further substances Layer of the organic electroluminescent device can react undesirably.

As explained above, molecules with hydroxyl groups are particularly effective quenchers. The more hydroxyl groups are present, the better the corresponding.

Extinguishing effect of the molecules. According to one embodiment of the invention, therefore, an organic electroluminescent device is provided in which the (e-v) quenching substance contains organic molecules having at least one hydroxyl group, wherein the ratio of total molecular weight of these

Molecules to the molecular weight of the hydroxyl groups is at most 5 to 1, preferably at most 3.5 to 1. For example, the ratio of total molecular weight to molecular weight of one or more hydroxyl groups in the alcohol-methanol is only 1.88 (total molecular weight M _ges = 32 g / mol, molecular weight of the hydroxyl groups M _0H = 17g / mol), with ethanol 2.7 (MgSs = 46 g / mol, M ₀ H = 17 g / mol), with ethylene glycol only 1.82 (M _tot = 62 g / mol, M _0H = 34 g / mol). Even with carbohydrates, low values of this ratio of molecular weights can be achieved. For example, a result for cellulose Value of M _tot / M _0H = 3.17. Sorbitol as an (ev) quencher even has a value of only M _ges / M _0H = 1.78.

One way of applying the at least one organic electroluminescent layer to a substrate for making the organic device is a coating of the liquid or gel phase, such as, e.g. Spin coating, dip or groove coating or printing techniques, in particular ink-jet printing, screen printing or flexographic printing. In this case, a solution in which the organic electroluminescent molecules and / or their starting substances are dissolved, deposited on the substrate, or the substrate pulled out of the solution, so that a liquid film forms on the substrate surface. The organic electroluminescent layer is then produced from the liquid film by drying and / or a reaction of starting substances, such as a polymerization. The (e-v) quenching substance can be easily incorporated in this embodiment of the invention by dissolving the (e-v) quenching substance in a coating solution and applying it together with the active molecules or their precursors as a functional layer on the substrate.

A further possibility of applying organic functional layers, in particular also the electroluminescent layer, to a substrate is to deposit these by vapor deposition. This method is particularly suitable for those functional molecules of the functional layer which have low molecular weights. In this case, according to a development of this embodiment of the invention, the (ev) quenching substance by co-evaporation together with the active molecules of the electroluminescent layer are deposited to introduce the quenching substance in the electroluminescent layer.

In order to introduce the (e-v) quenching substance into the organic electroluminescent layer, the (e-v) quenching substance may also be present outside the electroluminescent layer and then diffuse into it.

For this purpose, the (e-v) quenching substance can advantageously also be applied in a separate layer before or after the application of the electroluminescent layer, ie as a base or covering of the electroluminescent layer. The quenching substance may then at least partially diffuse from the separate layer into the functional electroluminescent layer. In this case, the separate layer can also dissolve, for example. Options include:

^• applying a preferably thin layer with the (ev) -with or without matrix, to

Example in the wells of a display that are filled with inkjet technology. Overlaying this layer with a layer of a solution containing the electroluminescent material, dissolution of the (ev) quenching layer by the solvent of the electroluminescent layer, mixing by diffusion of the materials in the liquid phase and subsequent formation of the electroluminescent layer with the (ev ) Quenching substance by removal of the solvent and / or crosslinking. The reverse order of ^'layer application is also possible.

^• application of a preferably thin layer of the (e- v) quenching with or without a matrix. Overlay this layer with a layer of a solution, the contains the electroluminescent material, but with solvents in which the (ev) quenching substance is not soluble, ie formation of a separate film. Subsequently, diffusion of the (ev) quenching substance into the electroluminescent layer, also for example supported by suitable measures, such as optical or thermal excitation or activation. The reverse order of the layer application is also possible.

Transfer of the (ev) quenching substance into the electroluminescent layer by applying the (e- v) quenching substance as a layer to a support, "face-to-face" covering of the electroluminescent layer with the support, ie opposing placement of support and electroluminescent layer with contact of carrier and layer or non-contact. The release of the (ev) quenching substance on the carrier can be effected by thermal and / or optical action, for example also locally, for example by irradiation with a laser. Subsequently, diffusion of the (ev) quenching substance into the electroluminescent layer takes place. As a result, the quenching substance can also be deposited in a structured manner in a simple manner. ^"According to yet another embodiment of the invention is provided to encapsulate the electroluminescent layer in a cover, wherein the (ev) is included in the cover and then is present inside the cover. The cover can thereby ^• in particular also form a cavity, in The (e v) quenching substance enclosed in the cavity can then partially diffuse into the organic functional layer as well. It is also possible that the singlet oxygen formed in the organic electroluminescent layer is diffused into the cavity and thus to the (ev) quenching substance and deactivated there, so that an equilibrium of ground state and singlet oxygen is established throughout the component which is harmless to the component or at least reduces the amount of singlet oxygen present in the component.

Other possibilities directly or via diffusion (e-v) - to introduce Löschsubstanzen in the component are:

Embedded in a patterned insulating or resistive layer between the two electrode layers, which serves to locally interrupt or attenuate the flow of current to provide patterned luminous surfaces;

Provide a so-called "black-matrix" masking with the (e-v) quenching substance to cover the cathode reflections between the pixels of a. OLED displays within component layers,

• storage of the (ev) quenching in tear-off webs, ^• for example in the form of structures with mushroom-shaped cross-section, typically made of photoresist, such as those used for cathode patterning in the manufacture of OLED displays.

Also, according to yet another embodiment of the invention, a barrier layer with a (ev) quenching substance can be applied, which protects the organic electroluminescent layer. In addition, it can also act as a barrier to prevent, for example, the penetration of further oxygen or even moisture at least slow it down. Further embodiments of the invention in which a (ev) outside the organic electroluminescent Schicht.in the component ^'is introduced see before, to use a substrate having a

(ev) quenching substance or in which a film with an (ev) quenching substance is applied. Again, the film or substrate can neutralize singlet oxygen that diffuses into or out of the substrate or film. ^{In this case,} for effective protection of the organic functional layer, the film or the substrate may be in contact with the at least one organic electroluminescent layer in order to reduce diffusion paths up to a neutralization of the singlet oxygen.

Organic components often also have adhesions, for example in order to connect an encapsulation to a substrate of the component. A further development of the invention provides that an adhesive which contains an (e-v) quenching substance is used for bonding at least one part to the substrate. One such refinement offers, inter alia, the advantage that it is also possible to use (e-v) extinguishing substances which, if they were arranged inside the functional layer, would be the

Properties of the organic functional layer would adversely affect.

^• In order to keep the influence of the (ev) on the organic functional layer as low as possible, it is furthermore advantageous if the HOMO and LUMO states of the molecules of the (ev) quenching a higher energy gap than the HOMO and LUMO states of the active molecules of the organic electroluminescent layer. It is also possible to introduce an (ev) quenching substance in the form of particles. The particles can be very small and therefore also include in particular nanoparticles. Within the meaning of the invention, particles are understood as meaning not only solid particles but also liquid or gel-like droplets which are, for example, dispersed or emulsified. The particles may consist of the (ev) quenching substance itself, or contain these, for example on the surface or have OH groups on the surface.

Advantageously, further measures for protecting the organic electroluminescent component against the action of oxygen and other reactive substances can also be provided. Another effective protection is a getter material for water and / or oxygen.

In the following the invention will be with reference to embodiments and with reference to the drawings ^■ explained in more detail, wherein identical and similar

Elements are provided with the same reference numerals and the features of various embodiments can be combined.

Show it:

1 shows a first exemplary embodiment of an organic electroluminescent component according to the invention designed as an OLED,

Fig. 2 shows another embodiment of an OLED configured ^as' organic electroluminescent device according to the invention, Fig. 3 shows an embodiment with structured

Resistive layer which the (e-v) -

Contains extinguishing substance, 4 shows a schematic state diagram with HOMO and LUMO states of the active molecules of the organic layer and the (ev) quenching substance, FIG. 5 shows a variant of the embodiment shown in FIG. 1 with an (ev) -

Extinguishing substance-containing film, and

6 shows a particle embedded in the organic functional layer with an (e-v) quenching substance.

1 shows a first exemplary embodiment of an organic electroluminescent component designated as a whole by the reference numeral 1, or an OLED.

The layer structure of an OLED, like her. is shown schematically in Fig. 1, and the suitable materials are known in the art. In general, an OLED typically comprises a layer sequence with an organic electroluminescent layer having an organic electroluminescent material, which is arranged between two electrode layers of the layer sequence.

In addition, further functional layers can be provided between the electrode layers in order, among other things, to increase the quantum efficiency of the OLED. For example, a so-called hole transport layer is often used to compensate for the different mobilities of injected holes and electrons.

The component 1 comprises a substrate 3 with sides 31, 32, on which a transparent electrode layer 7 is deposited. As a transparent electrode layer 7, for example, the conductive transparent indium tin oxide in question. On with the electrode layer. 7 coated side 31 of the substrate, an organic electroluminescent layer 5 having an organic electroluminescent substance is deposited. The layer 5 can be, for example, a polymer layer which is applied by means of liquid coating. Likewise, however, the organic electroluminescent layer 5 can also be vapor-deposited. As mentioned above, further functional layers may be present in the layer sequence between the electrode layers 7, 9. These are known in the art and not shown for the sake of clarity in Fig. 1.

On the first electrode layer 7 and the organic electroluminescent layer 5 provided side 31 of the substrate, a further electrode layer 9 is applied. The electrode layer 9 is preferably a metal layer having an electronic work function different from the first electrode layer 7. It is favorable to choose for the electrode layer 9 a material with a work function which is lower than the work function of the first electrode layer 7. Suitable materials include aluminum, barium or calcium. Other materials are known in the art. However, the layer sequence can also be designed inversely, wherein a transparent cover is provided on the substrate, through which the generated, light can escape.

Due to the different work functions are starting from the one electrode layer holes in occupied

States of the organic electroluminescent substance of the layer 5 and starting from the other electrode layer, electrons in unoccupied states, which then recombine in the electroluminescent molecules under electroluminescence. The suitable electroluminescent Materials are typically oxygen sensitive. Likewise, the electrode layer 9 can also oxidize. In order to protect the sensitive layers 5, 9, in the embodiment shown in Fig. 1, a cover 11 with the substrate 3 to form splices or

Glued bonds 13 glued. The cover 11 includes a cavity 12 a. As a further protective measure for the layers 5, 9, a getter material 15 for water and / or oxygen is also present within the cavity 12 on the cover 11. As getter 15 is suitable among other calcium oxide. Other coverage methods and designs are known to those skilled in the art.

According to the invention, in the organic component 1 formed as an OLED, there is also an (e-v)

Extinguishing substance 4 for singlet oxygen present. The extinguishing substance 4 may in particular be present in the functional layer 5, as shown in FIG. 1. One possibility for introduction into the layer 5 is, in the case of a liquid coating of the side 31 of the substrate 1, simply to dissolve the (e-v) -exiting substance 4 in the polymeric or dendrimeric solution to be applied and to apply it together with the other component or components of the layer. Another possibility is, in the case of a vapor-deposited layer 5, to deposit the (e-v) quenching substance 4 by co-evaporation together with the active molecules-in the case of an OLED, in particular, the electroluminescent molecules-of the functional layer 5.

Another possibility for introducing the (ev) - extinguishing substance 4 into the functional layer 5, which can be provided alternatively or additionally, is to introduce the (ev) quenching substance 4 within the cover 11, which encapsulates the functional organic layer 5. The quenching substance 4 is then in by the Cover formed cavity 12 available. If the molecules of the quenching substance 4 have a sufficiently low molar mass, then the molecules can also diffuse into the functional layer 5 in sufficient quantity while establishing an equilibrium vapor pressure.

The (e-v) quenching substance can also be applied in a separate layer before or after the application of the electroluminescent layer 5. From this separate layer, the quenching substance 4 can then at least partially diffuse into the organic electroluminescent layer 5. The separate layer can also dissolve completely.

Also, as shown in FIG. 1, the (e-v) quenching substance 4 alternatively or additionally in the

Gluing 13 may be present, for example, by a glue containing the quenching substance 4 is used when gluing the cover 11 adhesive.

FIG. 2 shows a further exemplary embodiment of an organic electroluminescent component 1 according to the invention. The component 1, like the component shown in FIG. 1, may have a cover 11. However, the cover or other encapsulations are omitted for the sake of clarity in Fig. 2.

In this embodiment, a conductive barrier layer 17 for the functional organic layer 5 is additionally provided on the conductive transparent electrode layer 7. Between the electrode layers 7 and 9 there is also a hole transport layer 19 as another functional layer, as is often used in OLEDs, in order to increase the quantum efficiency. Indium tin oxide as a transparent conductive electrode layer 7 releases oxygen over time. The barrier layer serves as an oxygen barrier to prevent or slow down the penetration of oxygen into the functional layers 5 and 19. In order to improve the protection of the organic functional layer 5 and / or the hole transport layer 19, it is further provided in this embodiment that the barrier layer 17 contains an (ev) quenching substance.

In addition, here too, as shown in FIG. 2, an (e v) quenching substance may also be incorporated in the organic electroluminescent layer 5.

The illustrated in Fig. 3 embodiment of an organic device 1 according to the invention additionally comprises a laterally structured insulation or resistive layer 35 between the electrode layers 7 and 9. The layer 35 is so laterally, so structured along the substrate surface, that they the underlying surface in areas 37 covered and released in areas 39. In the example shown in FIG. 3, the layer 35 covers the surface of the electrode layer 7. By means of the insulating or resistive layer 35, the current flow between the electrode layers 7, 9 in the covered regions 37 is interrupted or at least attenuated. Accordingly, in these areas, the electroluminescent layer 5 is not excited or weaker, so that these areas 37 remain dark or darker during operation. This will create a structured illuminated area. In this way, for example, information such as logos, symbols and logos can be displayed. In this embodiment, in particular, the (ev) quenching substance 4 is incorporated in the insulating or resistive layer 35. This can according to According to a development of the invention, after the organic electroluminescent layer 5 has been applied, it is also at least partially diffused into the layer 5 so as to be effective also in the region (s) 39 and the organic substances of the layer 5 in these regions are not degraded by singulation. To protect oxygen.

The selection of suitable (ev) quenching substances advantageously also takes place on the basis of the distances between the electronic states of the active molecules and the molecules of the (ev) quenching substance. Fig. 4 shows for clarity a schematic state diagram. The solid lines represent the highest occupied molecular orbital ("HOMO") and the lowest unoccupied molecular orbital ("LUMO") of the active molecules. The dashed lines indicate the HOMO and LUMO states of the molecules of the (ev) quenching substance. In order to keep the influence on the electrical and / or electro-optical properties of the active layer as small as possible, the (ev) is selected so that ^'as shown in the diagram, the HOMO and LUMO states of the molecules of the (ev) Quenching substance have a higher energy gap than the HOMO and LUMO states of the active molecules of the organic functional layer.

If the LUMO states of the molecules of the (ev) quenching substance are too low, they can act as trap states for electrons flowing through the layer. Likewise, energetically high HOMO states of the molecules of the (ev) quenching substance can act as traps for holes. In both cases, for example, the flow of current through the layer can be adversely affected. Also, in an electroluminescent organic layer 5, as used in the embodiments of FIGS. 1 and 2 is present, by this fall action to a damping of Electroluminescence and thus come to a reduction in quantum efficiency.

In order to achieve efficient quenching of singlet oxygen, the (ev) quenching substance is further preferably selected to contain molecules having at least one functional group having a terminal oscillator whose vibrational energy equals the fundamental vibration or an overtone of the stretching vibration equal to the energy difference between the

02 (alΔg) - and the 02 (X ^ Σ ^~ g) state of molecular oxygen or whose vibrational energy of this energy difference by more than 37%, preferably at most 10% deviates.

This condition is particularly fulfilled by molecules containing at least one hydroxyl group. Also suitable in this regard are still molecules with at least one NH or NÜ ₂ group, or C-H bonds, but an NH bond or C-H bond exhibit a lower deactivation efficiency compared to an OH bond as a terminal oscillator. The energies of the stretching vibration are at E = 2960 cm ^"1 for a CH, E = 3355 cm ^{" 1} for a NH and 3755 cm ^"1 for a 0-H bond.

Suitable substances with such terminal 0-H, C-H or N-H oscillators include: mono- or polyhydric alcohols, for example, ethanol, ethylene glycol, glycerol, cyclohexanol;

Carbohydrates, for example mono-, di- and trisaccharides; Cellulose derivatives and / or starch derivatives, for example cellophane; Glycerol monooleate, for example glycerol monooleate, glycerol monooricinoleate, glycerol monostearate; amino alcohols; polyamines; Polyamides.

Cellulose derivatives, starch derivatives, polyamines and polyamides are also examples of an (e-v) quenching substance comprising a polymer having hydroxyl groups or NH or NH 2 groups. Such (e-v) quenching substances may be used, for example, in the form of a film or substrate for the organic functional layer in the organic device. For example, the substrate 3 of the embodiments shown in FIGS. 1 or 2 may comprise such a polymer.

An embodiment with a foil with a polymeric (ev) quenching substance is shown in FIG. 5. This embodiment is a variant of the OLED shown in FIG. The layers 5, 7, 9 of this organic component are covered with a film 29 of polymeric (ev) quenching substance arranged inside the cover 11. The film 29 can be fixed, for example, as shown in Fig. 5, with the bonds 13. As (ev) quenching substance 4 for the film, inter alia _. Polyimide, polyamide or a starch or cellulose derivative, such as cellophane can be used. In addition, (ev) quenching substance in the bond 13 and / or the cavity may also be present.

Other than shown in FIG. 5, the organic device may be constructed such that the film 29 or the substrate having the (ev) quenching substance is in contact with the organic electroluminescent layer 5. It is also possible to use an (ev) quenching substance in the form of particles. Fig. 6 shows an example of such a (ev) quenching substance in particulate form. The (ev) quenching substance 4 of this embodiment comprises

Nanoparticles 41, which are embedded in the organic functional layer 5. The nanoparticles 41 comprise molecules 42 having a non-polar end 43 symbolized by a dash and one or more circle-symbolized hydroxyl groups at the other end of the molecule 42. Examples of such molecules include monohydric alcohols, such as ethanol, propanol or hexanol.

Hydroxyl groups increase the polarity of the molecule 42, which generally degrades solubility in an organic, non-polar environment. On the other hand, hydroxyl groups are outstandingly suitable as terminal oscillators to deactivate singlet oxygen, or to convert it into the triplet ground state.

In the form of particles, as shown by way of example in FIG. 6, molecules with poor solubility can now also be embedded in an organic functional layer. In this case, the nonpolar radicals 43 of the molecules 42 in the particle to the outside, so that the polar OH groups are in the interior of the particles 41. In this way, even further molecules 45 of the (ev) quenching substance can be embedded in the interior of the particles 41, which are only poorly soluble or not at all soluble in the active organic layer 5 owing to the ^" high number of polar OH groups.

The singlet oxygen is in this embodiment, especially during the Diffusion by the nanoparticles 41 impact-induced deactivated.

It will be apparent to those skilled in the art that the invention is not limited to the exemplary embodiments described above, but rather may be varied in many ways. In particular, the features of the individual embodiments can also be combined with each other.

Reference sign list:

I Organic component

3 substrate

4 (e-v) quenching substance

5 organic functional layer

7 conductive transparent electrode layer

9 electrode layer

II cover

12 cavity

13 bonding

15 getter material

17 barrier layer

19 hole transport layer

21 Siθ ₂ insulation layer 3, 25 electrodes 7 insulation layer

29 Polymer film 1.32 Page of 3 5 laterally structured insulation layer 7 of 35 covered area 9 of 35 uncovered area 1 nanoparticles 2, 45 molecules of 4, 41 3 nonpolar end of 42, 4 hydroxy group

Claims

claims

1. An organic electroluminescent device having at least one organic functional layer, characterized by an (e-v) quenching substance for singlet oxygen

2. An organic electroluminescent device according to claim 1, characterized in that the

Molecular weight of the (e-v) quenching substance is less than 528 g / mol, preferably less than 374 g / mol, particularly preferably less than 178 g / mol.

3. An organic electroluminescent device according to claim 1 or claim 2, characterized in that the (e-v) quenching substance contains molecules having at least one functional group with a terminal oscillator having a vibrational energy of the fundamental vibration or an overtone of the stretching vibration equal to that

Energy difference between the 02 ^ ¹ Ag) - and the

02 (χ3Σ ^~ g) state of molecular oxygen or whose vibrational energy from said energy difference by at most 37%, in particular with n <= 2 preferably differs by at most 10%.

4. An organic electroluminescent device according to any one of the preceding claims, characterized in that the (ev) quenching substance contains molecules having at least one functional group with a terminal oscillator having a vibrational energy of an overtone of the stretching vibration with n <= 3 equal to the energy difference between the 02 (a ^ Δg) - and the O2 (X ^ Σ ^~ g) state of molecular

Oxygen is or whose vibration energy of this energy difference by more than 37%, preferably at most 10% deviates.

5. An organic electroluminescent device according to at least one of the preceding claims, characterized in that the (e-v) quenching substance contains organic molecules having at least one hydroxyl group.

6. Organic component electroluminescent according to at least one of the preceding claims, characterized in that the (e-v) quenching substance contains molecules with at least one NH or NH 2 group.

7. Organic electroluminescent device according to at least one of the preceding claims, characterized in that the (e-v) quenching substance comprises a polymer having hydroxyl groups or NH or NH 2 groups.

8. An organic electroluminescent device according to at least one of the preceding claims, characterized in that the (e-v) quenching substance contains at least one of a monohydric or polyhydric alcohol, a carbohydrate.

9. An organic electroluminescent device according to at least one of the preceding claims, characterized in that the (ev) quenching substance is present in the functional layer.

10. An organic electroluminescent device according to at least one of the preceding claims, characterized in that the (e-v) quenching substance is present within a cover which encapsulates the at least one functional organic layer.

11. Organic electroluminescent device according to at least one of the preceding claims, characterized by a barrier layer with an (e- v) quenching substance.

12. Organic electroluminescent component according to at least one of the preceding claims, characterized by a bond with a

Substance consisting of or containing an (e-v) quenching substance.

13. Organic electroluminescent component according to one of the preceding claims, characterized by particles, in particular nanoparticles, which contains an (e-v) -solvent substance at least on the surface.

14. An organic electroluminescent component, characterized by a laterally structured insulation or resistive layer between the electrode layers of the device, wherein the insulating or resistive layer contains the (e-v) - quenching substance.

15. Organic component according to one of the preceding

Claims, characterized in that the HOMO and LMEO states of the molecules of the (ev) quenching substance have a higher energy gap than the HOMO and LUMO states of the active molecules of the organic functional layer.

16. An organic electroluminescent device according to at least one of the preceding claims, characterized in that the (e-v) quenching substance is a film or a substrate for the. organic functional layer.

17. An organic electroluminescent device according to claim 16, characterized in that the film or the substrate is in contact with the at least one functional organic layer.

18. Organic electroluminescent device according to at least one of the preceding claims, characterized in that the (e-v) quenching substance in a concentration of at most 5 percent by weight of the active substance of the organic functional

Layer, preferably at most 1 weight percent is present in the organic functional layer.

19. An organic electroluminescent device according to at least one of the preceding claims, characterized by an (e-v) quenching substance in the form of particles.

20. Organic component according to one of the preceding claims, characterized by a getter material for water or oxygen.

21. Organic electroluminescent device according to one of the preceding claims, characterized in that the (ev) quenching substance organic Contains molecules having at least one hydroxyl group, wherein the ratio of total molecular weight of these molecules to the molecular weight of the hydroxy groups is at most 5 to 1, preferably at most 3.5 to 1.

22. A process for producing an organic electroluminescent component, in particular an organic electroluminescent component according to one of the preceding claims, in which a layer sequence with two electrode layers and at least one electroluminescent layer is applied to a substrate, characterized in that in the layer sequence or in contact with this (ev) quenching substance is introduced.

23. The method according to claim 22, characterized in that the electroluminescent layer on the substrate by means of coating from the liquid or gel phase, in particular spin coating, dip or

Channel coating, or a printing technique, in particular ink-jet printing, screen printing or flexographic printing is applied.

24. The method according to claim 23, characterized in that the (e-v) quenching substance dissolved in a coating solution and applied together with the active electroluminescent molecules or their starting materials as an electroluminescent layer on the substrate.

25. The method according to any one of the preceding claims, characterized in that at least one organic electroluminescent layer is deposited by vapor deposition.

26. The method according to claim 25, characterized in that the (e-v) quenching substance is deposited by co-evaporation together with the active molecules of the electroluminescent layer.

27. A method according to any one of the preceding claims, wherein the electroluminescent layer is encapsulated in a cover, characterized in that the (e-v) quenching substance is trapped in the cover.

28. The method according to any one of the preceding claims, characterized in that a barrier layer is applied, which contains an (e-v) quenching substance.

29. A method according to any one of the preceding claims, wherein a substrate is used which contains a (e- v) quenching substance or in which a film with an (e-v) quenching substance is applied.

A method according to any one of the preceding claims, wherein at least a portion is adhered to the substrate, characterized in that an adhesive having an (e-v) quenching substance is used.

31. Method according to one of the preceding claims, characterized in that the (e-v) quenching substance diffuses into the at least one electroluminescent layer.

32. The method according to claim 31, characterized in that the (ev) quenching substance in a separate layer is applied before or after the application of the electroluminescent layer.

33. The method according to any one of the preceding claims, characterized in that an (e-v) quenching substance is introduced which contains molecules having at least one hydroxyl group or at least one NH or NH2 group.

34. The method according to any one of the preceding claims, characterized in that an (e-v) quenching substance is introduced, which contains an alcohol.

35. The method according to any one of the preceding claims, characterized in that an (e-v) quenching substance is introduced which comprises a polymer having hydroxyl groups or NH or NH2 groups.

36. The method according to any one of the preceding claims, characterized in that the (e-v) quenching substance is introduced in the form of particles.

37. Use of (e-v) quenching substances, in particular having a molecular weight of less than 528 g / mol in organic electroluminescent components.