WO2005106987A1

WO2005106987A1 - Layer arrangement for an organic light-emitting diode

Info

Publication number: WO2005106987A1
Application number: PCT/DE2005/000820
Authority: WO
Inventors: Jan Blochwitz-Nimoth; Jan Birnstock
Original assignee: Novaled Ag
Priority date: 2004-05-03
Filing date: 2005-05-02
Publication date: 2005-11-10
Also published as: DE102004022004A1; CN1950960A; DE102004022004B4; KR20070009730A; JP2007536717A

Abstract

The invention relates to a layer arrangement for an organic light-emitting diode (OLED) of the top-emitting type and to a display device and a lighting device comprising said layer arrangement. The layer arrangement comprises a lower electrode (A), an upper, transparent electrode (K), and an organic layer area (O) which is disposed between the two electrodes (A; K) so as to contact the lower and the upper electrode (A; K). Light can be generated in said organic layer area by recombination of electrons and holes and emerges through the upper electrode (K). The lower electrode (A) has a layer structure wherein a lower electrode layer is a metal layer. The invention is characterized in that a protective and modifying layer is arranged in the layer structure of the lower electrode (A) on top of the metal layer and contacts the organic layer area (O).

Description

Layer arrangement for an organic light-emitting diode

The invention relates to an arrangement with an organic light-emitting diode (OLED) as well as a display element and a lighting device using the arrangement.

The graphic representation of information plays an increasingly important role in many areas of daily life. Technical devices are increasingly being equipped with display devices of various sizes, which serve to entertain or inform the user. The demands on the quality of the image output are steadily increasing.

The majority of display devices used today are based on the principle of the cathode ray tube or the liquid crystal display. In addition, there are other flat display technologies such as plasma, electroluminescence, vacuum fluorescence or field emission displays. With the displays based on organic light-emitting diodes, serious competition for the established technologies has grown in recent years. Brilliant colors, excellent contrast, self-emissivity, fast switching times even at low temperatures, wide viewing angles and a large fill factor are the advantages of this technology. In addition to displays, OLEDs are also used in lighting elements. The advantage of OLEDs is their high energy efficiencies, their low operating voltages and the possibility of producing flat-emitting components in any color.

In contrast to inorganic light-emitting diodes, organic light-emitting diodes are flat components. In OLEDs, an organic layer area with one or more layers of organic material is embedded between two electrodes, at least one of which must be transparent. Conductive oxides, so-called TCOs ("transparent conductive oxides"), are generally used for the transparent of the two electrodes. If the electrode between a substrate on which the electrodes and the organic layer area are arranged and the organic layer area (lower electrode) is transparent, one speaks of a “bottom emission OLED”, and the other electrode (upper electrode) is transparent it is a "top emission OLED". Components in which both electrodes are transparent can also be formed. With all different construction methods, the emitted light is generated in a so-called emission zone on the basis of radiative recombination of electrons and defect electrons (holes). The light leaves the component through the transparent electrode.

The lower electrode, which is on the substrate, has to fulfill a number of properties. For example, ITO has found a satisfactory solution for bottom-emitting components. For top-emitting components, however, the selection of a suitable electrode material is difficult. Top-emitting OLEDs are required in order to be able to integrate OLEDs in so-called backplanes (forms the substrate) of active matrix displays. For this purpose, the backplanes with their TFT electronics circuit (TFT - "thin film transistor") and a final contact are preferably manufactured in a factory for amorphous-Si (a-Si) or polycrystalline-Si (poly-Si) backplane production , Then they are transported to the location of the OLED production, preferably in air. The OLED is then applied to the final upper contact of the backplane, for example by vacuum evaporation. The top contact of the backplane forms the basic contact for the OLED. Areas between the display elements of a display device manufactured in this way are separated from one another with the aid of a structured insulation layer. The insulation layer is also manufactured in the a-Si or poly-Si factory.

A layer arrangement with an OLED in top-emitting design is known from document US 2002/0117962 AI. The top electrode of the OLED is a transparent cathode. The lower anode of the OLED, which is arranged on a substrate, is formed with the aid of several layers. A metal layer, which can also be a stack of several metal layers, is arranged on the substrate. Different metals or alloys are proposed for the metal layer, with which an anode suitable for the OLED can be formed. The metal layer has an excellent reflectivity for light of the visible spectrum. A barrier layer is applied to the metal layer, which can also be multi-layered. The material of the barrier layer can be conductive or insulating. With the help of the barrier layer, the metal layer is physically and chemically separated from an anode modification layer arranged on the barrier layer. The material for the anode modification layer can also be conductive or insulating. With the help of the anode modification layer, the work function for the holes from the anode is set and a stable interface to the organic layer area located above is made possible. In the document US 2002/0117962 AI different embodiments for materials and layer thicknesses for both Metal layer as well as the barrier layer and the anode modification layer described. The multilayer structure of the anode in the known OLED complicates the manufacturing process.

The object of the invention is therefore to provide an improved layer arrangement for an OLED and an improved display device / lighting device using the arrangement, which can be produced with reduced effort and inexpensively. _,

This object is achieved by a layer arrangement according to independent claim 1, a display device according to independent claim 19, a lighting device according to independent claim 20 and a method according to independent claim 21.

The invention encompasses the idea of providing a layer arrangement for an organic light-emitting diode (OLED) in a top-emitting embodiment, with a lower electrode, an upper electrode which is transparent, and an organic layer region which is in contact with the lower and the upper Electrode is arranged between the two electrodes and in which, by means of recombination of electrons and holes, light can be generated which exits through the upper electrode, the lower electrode having a layer structure in which a lower electrode layer is a metal layer, the lower structure in the layer structure A protective and modification layer is arranged on the metal layer and is in contact with the organic layer region.

A significant advantage, which is achieved with the aid of the invention compared to the prior art, is that the layer structure of the lower electrode is simpler with a top-emitting OLED and, moreover, the diverse requirements for such a contact layer described below are better met.

It has surprisingly been found that even with the layer structure of the lower electrode shown, the following advantageous properties can be achieved with the aid of a suitable choice of materials and thicknesses for the layers of the lower electrode: i. high reflectivity for light in the visible spectral range, ii. low electrical resistance, iii. low roughness, iv. Adaptability of the work function for the injected charge carriers with regard to the organic layer area, v. Avoiding the formation of surface layers under normal environmental influences (oxygen, moisture), which reduce the properties of the OLED on this layer system, for example due to barrier formation for charge carrier injection from the contact layers into the layers of the OLED, and vi. Structurability of the electrode.

All of these advantageous properties or any sub-combination of individual properties can be implemented in the layer arrangement according to the invention and the display device / lighting device according to the invention.

Advantageous embodiments of the invention are the subject of dependent subclaims.

The invention is explained in more detail below using exemplary embodiments with reference to a drawing. Here show:

1 shows a schematic cross-sectional representation of a layer structure for a lower electrode of a top-emitting OLED;

FIG. 2 shows a schematic cross-sectional illustration of a section of a display device with OLEDs using a lower electrode according to FIG. 1;

3 A and 3B are schematic cross-sectional representations of a layer structure with an OLED in normal construction and inverted construction, an organic layer region being constructed in one layer;

4A and 4B are schematic cross-sectional representations of a layer structure with an OLED in normal construction and inverted construction, an organic layer region being constructed in multiple layers;

5A and 5B are schematic cross-sectional representations of a layer structure with an OLED in normal construction and inverted construction, an organic layer region having a p-doped hole transport layer and an n-doped electron transport layer; and 6A and 6B are schematic cross-sectional representations of a layer structure with an OLED in normal construction and inverted construction, an organic layer region having a p-doped hole transport layer, an n-doped electron transport layer and intermediate layers.

1 shows a schematic cross-sectional representation of a layer structure for a lower electrode 10 in a top-emitting OLED. The layers of the layer structure shown in FIG. 1 are explained in more detail below. The layer structure for the lower electrode 10 according to FIG. 1 comprises the following layers:

(a) A layer of metal A layer 11a of metal is provided as the bottom layer with a thickness between 10 nm and 500 nm, preferably between 40 nm and 150 nm, which has the following properties: The conductivity is so great that a given current can be reached without high voltage drop can be transported. The voltage drop is less than about 0.2V. - Typically, the sheet resistance of the metal layer 11a is less than 10 Ω / sq. , preferably less than 1Ω / sq. - The roughness is low. Typically less than 2 nm RMS, preferably less than 1 nm RMS. These properties are achieved using metals such as Cr, Ti, Mo, Ta or the like, or mixtures thereof, for example CrMo. AI can also be used as a material if the layer thickness is less than 75nm. The metal materials are processed by means of sputtering, thermal evaporation or electron beam evaporation.

The layer 11a is preferably made of the same material that is used when using an OLED with a lower electrode, which is designed according to the invention, in a display device or a lighting device in a backplane for contact connections that conduct the current to the display elements with the OLED. These contact connections typically have a thickness of approximately 150 nm.

(b) Another layer of metal According to FIG. 1, a further layer 1 lb of metal is provided with a thickness between approximately 5 nm and 80 nm, preferably between approximately 15 nm and 40 nm. The further layer 11b forms in a stack together with layer 1 1a a metal layer 12 for the lower electrode 10. The metal layer 12 has the following properties: The reflectivity is greater than approximately 50%, preferably greater than approximately 80%. - The conductivity is so high that a given current can be transported without an excessive voltage drop. The voltage drop is less than about 0.2V. Typically, the sheet resistance of metal layer 12 formed from layers 11a and 1 lb is less than about 10Ω / sq. ₃ preferably less than about 1Ω / sq. The roughness is low, typically less than about 2 nm RMS, preferably less than about 1 nm RMS.

The further layer 11b made of metal has a high reflectivity. Suitable metals are, for example, Al, Ag or alloys with a high proportion (> 50%) of the reflective materials, for example AlTi alloys. The material for the further layer 11b is processed by means of sputtering, thermal evaporation or electron beam evaporation. With the help of a small layer thickness of the further layer 11b it is ensured that the total roughness of the stack for the metal layer 12 is still below approximately 2 nm RMS, preferably below approximately 1 nm RMS.

(c) Protection and modification layer According to FIG. 1, a protection and modification layer 13 made of a metal, an oxide or a nitride with a thickness between approximately 2 nm and approximately 50 nm, preferably between approximately 5 nm and 30 nm, is also provided. The stack with the metal layer 12 and the protection and modification layer 13 has the following properties: The layer structure with the metal layer 12 and the protection and modification layer 13 can be structured, for example by means of etching. - By means of a suitable choice of the material for the protective and modification layer 13, the work function of the stack is adapted to a subsequent organic layer area. - The protection and modification layer 13 protects the layers 11a, 11b below by preventing oxidation. - The reflectivity is greater than about 50%, preferably greater than about 80%. - The conductivity of the layer is so high that it can transport a given current without too high a voltage drop. The voltage drop is less than about 0.2V. The surface resistance of the stack is typically less than about 10Ω / sq., Preferably less than about 1Ω / sq. The roughness is low, typically less than about 2 nm RMS, preferably less than about 1 nm RMS.

The protection and modification layer 13 thus protects the layers 11a, 11b underneath from oxidation during transport of the backplane and from degradation during further processing. These properties can be achieved by using, for example, the following materials for the protection and modification layer 13: Ti _y N _x , ITO, Cr, Mo, Ta, Ti, Ni, Ni _y O _x , Ti _y O _x , Ni _y N _x , Pd _y O _x , Pt _y O _x , Pd _y N _x , Pt _y N _x and others, where x and y may be in the range of 1..4. The materials are processed by means of sputtering, thermal evaporation or electron beam evaporation.

In preferred embodiments, the layer 11a is made of Mo or Cr, the further layer 11b is made of Al or Ag and the protection and modification layer 13 is made of TiN or TiO _x .

In the embodiment according to FIG. 1, the metal layer 12 comprises the layer 11a and the further layer 11b, which are each described in detail above. An alternative embodiment (not shown) of the lower electrode 10 differs from this in that the metal layer 12 has a single layer. The single-layer metal layer is then carried out by means of a suitable choice of the material and layer thickness used so that it has the features described above for the metal layer 12 as a single layer, for example with regard to the reflectivity, the conductivity and the roughness.

In one embodiment, when used in a display device or a lighting device, the stack is structured with the layers 11a, 11lb before the protective and modification layer 13 is applied. The protection and modification layer 13 is then applied unstructured.

The functionality of the lower electrode 10 can also be retained if the protective and modification layer 13 is not structured. The transverse conductivity of the protection and modification layer 13 must then be so low that when using the lower electrode 10 for OLEDs in a display or lighting device, no short circuit between two adjacent display / lighting elements (pixels) is caused (cross-talk low) ). In a backplane manufacturing process for producing a display or lighting device, the stack with the layer 11a, the further layer 11b and the protection and modification layer 13 is applied over a large area, then structured laterally, for example by means of an etching process. The protection and modification layer 13 protects the layers 11a, 11b from damage during further processing. If no etching process is available with which the stack with the layer 11a, the further layer 11b and the protection and modification layer 13 can be structured together, the following process variants can alternatively be provided:

(1) Apply and structure layer 11a. Then the further layer 11b and the protection and modification layer 13 are applied and structured together.

(2) The layer 11a and the further layer 11b are applied and structured together. The protective and modification layer 13 is then applied without structuring. Then, however, the transverse conductivity of the protective and modification layer 13 must be small.

(3) The layer 11a and the further layer 11b are applied and structured together. The protective and modification layer 13 is then applied and structured.

It is advantageous to also use parts of a lower OLED contact, namely the lower electrode 10, to form the connection points (contact pads) for the external electronics. To achieve this, the following options exist: a) The layer 11a is structured in such a way that it also forms lateral display connections for connecting the display to external control electronics. These connections are usually made by bonding flat cables. b) The type of structuring explained under a) can also be carried out after the layer 11a and the further layer 11b, that is to say the metal layer 12, have been applied. c) Alternatively, the metal layer 12 and the protection and modification layer 13 are applied and structured individually or together in such a way that the layer combination also forms the connections for the external electronics.

A procedure according to process variants (2) and (3) presupposes that damage to the further layer 11b, which occurs when the layer 11a and the further layer 11b are structured, is so small that charge carriers are still effectively removed from the further layer 11b can be injected into the protection and modification layer 13. Furthermore The further layer 1 lb must not be damaged if the protection and modification layer 13 is structured (process variant 3).

A layer structure for the lower electrode 10, as described with reference to FIG. 1, can be used both in connection with an OLED in normal construction, in which the lower electrode is formed as an anode and light is emitted through an overhead transparent cathode. as well as in an OLED with an inverted structure, in which the cathode is formed with the aid of the lower electrode and light is emitted through a transparent anode located on top. An OLED with such a lower electrode can be used in particular for a display device 20 with display elements 20a, 20b, as shown in FIG. 2.

FIG. 2 shows a schematic cross-sectional representation of the display element 20, in which a back layer 22 is arranged on a substrate 21, which serves as a passivation layer on the one hand and in which electronic components are formed on the other hand, which serve to control OLEDs 23, 24. The back layer 22 is, for example, based on the known Si electronics, that is to say with structured or unstructured layers made of doped or undoped Si and structured or unstructured passivation layers made of oxides or nitrides of Si. Lower electrodes 23 a, 24 a for the OLEDS 23, 24 are applied to the back layer 22. The lower electrodes 23a, 24a are designed in accordance with one of the embodiments as explained in detail above in connection with FIG. 1. The lower electrodes 23a, 24a are connected to a respective organic region 23b, 24b in which light 25 is emitted. An upper electrode 26 extends above the organic regions 23b, 24b. Furthermore, a structured insulation layer 27 is provided according to FIG.

The use of the lower electrode 10 has been described in FIG. 2 for a display device 20. The explanations apply accordingly to a lighting device using several OLEDs with the lower electrode according to FIG. 1.

3 to 6, the following describes embodiments for an arrangement with an OLED, in which the lower electrode 10 is formed according to one of the embodiments explained with reference to FIG. 1, namely as a layer structure with the metal layer 12 can be made in one or more layers, and the protective and modification layer 13. The layer structure is shown in FIGS. Chen schematically indicated in the longitudinal direction of the respective lower electrode. The arrangements described in FIGS. 3 to 6 can be used in connection with display devices or lighting devices, as have been explained by way of example with reference to FIG. 2. The various embodiments in FIGS. 3 to 6 are described for OLEDs in normal construction and inverted construction. It has been found that it is possible with the aid of the layer structure for the lower electrode 10, a top-emitting OLED both in normal construction, in which the anode is arranged below the organic layer area and the cathode above the organic layer area, and also in inverted form To produce construction in which the cathode is arranged below the organic layer area and the anode above the organic layer area.

The inverted design has the advantage over the normal design that simple integration of the OLED with associated driver electronics is made possible, for example by means of CMOS technology or with amorphous n-channel Si TFTs. In addition, the arrangement of the cathode below the organic layer area has the advantage that the cathode is better protected against environmental influences such as oxygen or water. Environmental influences on the cathode materials on top can have an adverse effect on the long-term stability of the component, for example due to signs of detachment of the upper electrode. This can lead to problems with long-term stability due to partial vias (pin holes).

FIGS. 3A and 3B show a schematic cross-sectional representation of a layer structure with an OLED in normal construction (see FIG. 3A) and in inverted construction (see FIG. 3B). 3A and 3B, an organic area O, in which light is emitted by means of recombination of electrons and holes, has a single layer and, corresponding to the simplest structure of an OLED, is arranged between an anode A and a cathode K. The stack with anode A, cathode K and organic layer region O is arranged on a substrate S.

4A and 4B show schematic cross-sectional representations of a layer structure with an OLED in normal construction (cf. FIG. 4A) and in inverted construction (cf. FIG. 4B). In the embodiments in FIGS. 4A and 4B, the organic layer region O is embodied in multiple layers. An electron transport layer 40 takes over the transport function for the electrons. A hole transport layer 41 takes over the transport function for the solder rather. Light is emitted due to the recombination of electrons and holes in a boundary area 42 between the electron transport layer 40 and the hole transport layer 41, both of which are formed from an organic material. The boundary region can also be formed as an extra layer with the aid of another organic material.

5A and 5B show schematic cross-sectional representations of a layer structure with an OLED in normal construction (cf. FIG. 5A) and in inverted construction (cf. FIG. 5B). The organic layer region O is of multilayer design. A p-doped hole transport layer 50, an n-doped electron transport layer 51 and a light-emitting layer 52 are provided in the organic layer region O. Here, as is customary for inorganic semiconductors, doping is understood to be the targeted influencing of the conductivity of a semiconductor layer by adding foreign atoms / molecules. Doped charge carrier transport layers are described as such in various embodiments, for example in document DE 102 15 210 AI.

The layer sequence of an OLED can be reversed (cf. FIG. 5B), so that the hole-injecting contact (anode A) is implemented as a cover electrode. Usually this leads to the fact that the operating voltages are much higher with inverted organic light-emitting diodes than with comparable non-inverted structures. The reason for this is the poorer injection from the contacts into the organic layer area O, because the work function of the contacts can no longer be specifically optimized. When using an n-doped hole transport layer and / or a p-doped electron transport layer, this disadvantage can be overcome, since due to the doping, the injection of charge carriers from the electrodes A, K into the organic layer region O, regardless of whether the hole and / or in the electron transport layer 50, 51, no longer depends so much on the work function of the electrodes A, K itself. Due to the doping, the charge carrier transport layers 50, 51 can be made thicker without the operating voltage being increased.

A thin space charge zone is created in the doped charge carrier transport layers 50, 51 on the electrodes A, K, through which the charge carriers (electrons / holes) can be injected efficiently. Due to the tunnel injection, the injection is no longer hindered even with an energetically high barrier due to the very thin space charge zone. The respective charge carrier transport layers 50, 51 are advantageously doped by admixing an organic or inorganic substance (dopant). These big moles coolers are stably built into the matrix molecular structure of the charge carrier transport layers 50, 51. This ensures high stability when operating the OLED (no diffusion) and under thermal stress. For the hole transport layer, acceptor-like molecules are used as dopants, and donor-like molecules are used for the electron transport layer.

The reason for the increase in conductivity is an increased density of equilibrium charge carriers in the doped layers. The electron transport layer 51 can have thicker layers than is possible with undoped layers (with undoped layers typically a thickness between approximately 20 nm and approximately 40 mm) without drastically increasing the operating voltage. The hole transport layer 50 can also be made thicker than would be possible with undoped layers, without this leading to an increase in the operating voltage. So both layers are thick enough to protect the layers underneath from damage during the manufacturing process.

6A and 6B show a schematic cross-sectional representation of a layer structure with an OLED in normal construction (cf. FIG. 6A) and in inverted construction (cf. FIG. 6B), the OLEDs compared to the embodiments according to FIG. 5A and 5B additionally have intermediate layers in the organic layer region O.

Document DE 100 58 578.7 AI (see also X. Zhou et al., Appl. Phys. Lett. 78, 410 (2001)) describes that organic light-emitting diodes with doped charge carrier transport layers, as described above with reference to 5A and 5B have been shown to show optimal light emission when the doped charge carrier transport layers are suitably combined with intermediate layers. In the embodiments according to FIGS. 6A and 6B, charge carrier transport layers 60, 61 doped in the organic layer region O are therefore combined with intermediate layers 62, 63. The intermediate layers are each located between the charge carrier transport layer 60, 61 and a light-emitting layer 64, in which the conversion of the electrical energy of the charge carriers injected by current flow through the component into light takes place.

The substances of the intermediate layers 62, 63 are selected so that when the voltage is applied in the direction of the operating voltage, the majority charge carriers (holes or electrons) at the boundary layer doped charge carrier transport layer / intermediate layer are not excessively hindered due to their energy levels (low barrier), but the minority carriers efficiently at the interface between light emitting layer 64 and intermediate layer 62, 63 are held open (high barrier). Furthermore, the barrier height for the injection of charge carriers from the intermediate layer 62, 63 into the emitting layer 64 should be so small that the conversion of a pair of charge carriers at the interface into an exciton in the emitting layer 64 is energetically advantageous. This prevents exclex formation at the interfaces of the light-emitting layer 64, which reduces the efficiency of the light emission. Since the charge carrier transport layers 60, 61 preferably have a high band gap, the intermediate layers 62, 63 can be chosen to be very thin, since it is nevertheless not possible for the charge carriers to tunnel out of the light-emitting layer 64 into the energy states of the charge carrier transport layers 60, 61. This allows a low operating voltage to be achieved despite intermediate layers 62, 63. Under certain circumstances, the intermediate layers 62, 63 can also consist of the same material as the matrix material of the charge carrier transport layers 60, 61.

One embodiment (see FIG. 6A) comprises the following layer arrangement with a normal construction:

1. carrier substrate S,

2nd lower electrode (anode A),

3. p-doped, hole-injecting and transporting layer 60,

4. thin hole-side intermediate layer 62 made of a material whose band layers match the band layers of the layers surrounding them,

5. light-emitting layer 64 (possibly doped with emitter dye),

6. thin electron-side intermediate layer 63 made of a material, the band layers of which match the band layers of the layers surrounding them,

7. n-doped electron injecting and transporting layer 61,

8. upper electrode (cathode K), and

9. Encapsulation to exclude environmental influences.

Another embodiment (see FIG. 6B) comprises the following layer arrangement in the case of an inverted construction:

1. carrier substrate S,

2nd lower electrode (cathode K),

3. n-doped electron injecting and transporting layer 61

4. thin electron-side intermediate layer 63 made of a material, the band layers of which match the band layers of the layers surrounding them,

5. light-emitting layer 64 (possibly doped with emitter dye), 6. thin hole-side intermediate layer 62 made of a material whose band layers match the band layers of the layers surrounding them,

7. p-doped, hole-injecting and transporting layer 60,

8. upper electrode (anode A), and

9. Encapsulation to exclude environmental influences.

It can also be provided that only one of the intermediate layers 62, 63 is used, because the band layers of the charge carrier transport layer 60, 61 and the light-emitting layer 64 already match one another on one side. Furthermore, the functions of charge carrier injection and charge carrier transport in the charge carrier transport layers 60, 61 can be divided into several layers, at least one of which is doped to the respective electrode A, K. If the doped layer is not located directly at the respective electrode A, K, then all layers between the doped layer and the respective electrode A, K must be so thin that charge carriers can tunnel through them efficiently (approximately <10 nm). These layers can be thicker if they have a very high conductivity, the sheet resistance of these layers must be lower than that of the neighboring doped layer. Then the intermediate layers are to be regarded as part of the electrode A, K. The molar doping concentrations are typically in the range from 1:10 to 1: 10000. The dopants are organic molecules with molecular weights above about 200 g / mol.

The features of the invention disclosed in the above description, the claims and the drawing can be of significance both individually and in any combination for the implementation of the invention in its various embodiments.

Claims

Expectations

1. Layer arrangement for an organic light-emitting diode (OLED) in a top-emitting design, with a lower electrode (A; K), an upper electrode (K; A) that is transparent, and an organic layer area (O), which is arranged in contact with the lower and the upper electrode (A; K) between the two electrodes (A; K) and in which light can be generated by recombination of electrons and holes, which light can pass through the upper electrode (K; A) emerges, the lower electrode (A; K) having a layer structure in which a lower electrode layer is a metal layer (12), characterized in that in the layer structure of the lower electrode (A; K) on the metal layer (12) a protective and modification layer (13) is arranged, which is in contact with the organic layer region (O).

2. Layer arrangement according to claim 1, characterized in that the protective and modification layer (13) is made of a metal, an oxide or a nitride material.

3. Layer arrangement according to claim 1 or 2, characterized in that the protective and modification layer (13) has a layer thickness of about 2nm to about 50nm, preferably from about 5nm to about 30nm.

4. Layer arrangement according to one of the preceding claims, characterized in that the protective and modification layer (13) from one of the following materials or from a combination of two or more of the following materials: Ti _y N _x , ITO, Cr, Mo, Ta, Ti, Ni, Ni _y O _x , Ti _y O _x , Ni _y N _x , Pd _y O _x , Pt _y O _x , Pd _y N _x ,

Pt _y N _x .

5. Layer arrangement according to one of the preceding claims, characterized in that a stack with the metal layer (12) and the protective and modification layer (13) has a layer thickness of approximately 10 nm to approximately 500 nm.

6. Layer arrangement according to one of the. Preceding claims, characterized in that the stack with the metal layer (12) and the protective and modification layer (13) is highly reflective.

7. Layer arrangement according to one of the preceding claims, characterized in that the stack with the metal layer (12) and the protection and modification layer (13) has a roughness of less than about 2nm RMS, preferably less than about lnm RMS.

8. Layer arrangement according to one of the preceding claims, characterized in that the metal layer (12) is constructed in several layers from a plurality of individual metal layers (1 la, 1 lb).

9. Layer arrangement according to claim 8, characterized in that the metal layer (12) has a lower individual metal layer (11a) with a layer thickness of approximately 10 nm to approximately 500 nm, preferably with a layer thickness of approximately 40 nm to approximately 150 nm, and a further individual metal layer (11b) , which is arranged on the lower metal individual layer (11a) and is highly reflective, with a layer thickness of approximately 5 nm to approximately 80 nm, preferably with a layer thickness of approximately 15 nm to approximately 40 nm.

10. Layer arrangement according to claim 8 or 9, characterized in that one or all individual metal layers (11a, 1 lb) made of Al, Ag, an alloy of Al or Ag, Cr, Ti, Mo, Ta or a mixture of Cr, Ti, Are Mo and / or Ta.

11. Layer arrangement according to one of claims 8 to 10, characterized in that the lower individual metal layer (11a) and / or the further individual metal layer (11b) have a roughness of less than about 2 nm RMS, preferably less than about 1 nm RMS.

12. Layer arrangement according to one of the preceding claims, characterized in that the lower electrode (10) is applied to a substrate (S).

13. Layer arrangement according to claim 12, characterized in that in the substrate (S) a circuit for driving the lower and the upper electrode (A; K) are formed and the circuit via connection contacts with the lower and the upper electrode (A; K ) connected is.

14. Layer arrangement according to claim 13 and one of claims 8 to 11, characterized in that the lower metal single layer (11a) is made of a material from which a connection contact with the lower electrode (10) is formed.

15. Layer arrangement according to one of the preceding claims, characterized in that the layer structure of the lower electrode (10) has a sheet resistance of less than approximately 10 Ω / sq. , preferably less than about 1 Ω / sq.

16. Layer arrangement according to one of the preceding claims, characterized in that the lower electrode (10) is an anode (A) and the upper electrode is a transparent cathode (K).

17. Layer arrangement according to one of claims 1 to 15, characterized in that the lower electrode (10) is a cathode (K) and the upper electrode is a transparent anode (A).

18. Layer arrangement according to one of the preceding claims, characterized in that the organic layer region (O) comprises a p-doped hole transport layer (50; 60).

19. Layer arrangement according to one of the preceding claims, characterized in that the organic layer region (O) comprises an n-doped electron transport layer (51; 61).

20. Layer arrangement according to claim 20 or 21, characterized in that the organic layer region (O) comprises a hole-side (62) and / or an electron-side (63) intermediate layer.

21. Display device on a substrate (S) with one or more display elements, each of which has at least one organic light-emitting diode (OLED) in a top-emitting design with a layer arrangement according to one of claims 1 to 20.

22. Illumination device on a substrate (S) with one or more illumination elements, each having at least one organic light-emitting diode (OLED) in a top-emitting design with a layer arrangement according to one of claims 1 to 20.

23. A method for producing a display device or a lighting device, in which one or more display elements / lighting elements, each having at least one organic light-emitting diode (OLED) in top-emitting design with a layer arrangement according to one of claims 1 to 20, on a substrate (S), the method comprising the following steps: a) forming a lower electrode (A; K) on the substrate (S) by: a1) forming a metal layer (12) on the substrate (S); a2) a protective and modification layer (13) is formed on the metal layer (12); b) forming an organic layer region (O) on the lower electrode (A; K) so that the organic layer region (O) is in contact with the lower electrode (A; K); and c) forming an upper, transparent electrode (K; A) on the organic layer region (O) so that the organic layer region (O) is in contact with the upper electrode (K; A).

24. The method according to claim 23, characterized in that a plurality of individual metal layers (11a, 1 lb) are applied to form the metal layer (12).

25. The method according to claim 23 or 24, characterized in that the metal layer (12) is structured before the formation of the protective and modification layer (13).

26. The method according to claim 24 and claim 25, characterized in that a lower individual metal layer (11a) is applied and structured and then a further individual metal layer (1 lb) is applied and structured.

27. The method according to claim 25 or 26, characterized g ek ennz eic hnet that the protective and modification layer (13) is then applied and structured.

28. The method according to claim 25 or 26, characterized in that the protective and modification layer (13) is then formed unstructured.

29. The method according to claim 24, characterized in that after the application and the structuring of the lower individual metal layer (11a), the further individual metal layer (11b) and the protective and modification layer (13) are formed and structured together.

30. The method according to claim 23, characterized in that the metal layer (12) and the protective and modification layer (13) are applied over a large area to the substrate (S) and then structured.