WO2017085068A1

WO2017085068A1 - Organic light-emitting diode and method for producing an organic light-emitting diode

Info

Publication number: WO2017085068A1
Application number: PCT/EP2016/077755
Authority: WO
Inventors: Tobias Hero; Richard Baisl
Original assignee: Osram Oled Gmbh
Priority date: 2015-11-16
Filing date: 2016-11-15
Publication date: 2017-05-26
Also published as: DE102015119772A1

Abstract

An organic light-emitting diode is specified. The organic light-emitting diode comprises - a first electrode, - an organic layer stack for generating light, said stack being arranged above the first electrode, - a second electrode, which is arranged above the organic layer stack. The first electrode and/or the second electrode comprise(s) a first metallic layer and a barrier layer. In this case, the barrier layer is arranged between the first metallic layer and the organic layer stack. The barrier layer comprises a material selected from a group comprising an inorganic metal oxide, nitride and/or carbide or an organic material.

Description

description

Organic light emitting diode and method for producing an organic light emitting diode

An organic light-emitting diode and a method for producing an organic light-emitting diode are specified.

In organic light emitting diodes (OLEDs) metallic electrodes are often used. In particular, in the case of so-called bottom emitters, that is to say organic light emitting diodes which emit light from only one surface, the use of a light source is possible

highly reflective electrode necessary to obtain light emitting diodes with high efficiency. In particular, electrodes made of silver or comprising silver have a high reflectivity for

Light in the visible range of the electromagnetic spectrum, but are also suitable with appropriate choice of

Layer thickness as transparent electrodes. However, the use of silver electrodes leads to a reduction of the silver due to the interaction of the silver or an undesired reaction of the silver with the underlying or above organic functional layer stack

Lifetime of the LEDs. At least one object of certain embodiments is to provide an organic light-emitting diode that is very efficient on the one hand and has a long service life on the other hand. Another object is to provide a method for producing an organic light emitting diode.

These objects are achieved by the subject matter and the method according to the independent patent claims. Advantageous embodiments and developments of the objects and the Methods are characterized in the dependent claims and will be further apparent from the following description and drawings. An organic light-emitting diode is specified. The organic light-emitting diode comprises a first electrode, an organic layer stack for generating light which is arranged above the first electrode and a second electrode which is arranged above the organic layer stack.

The fact that a layer or an element is arranged or applied "on" or "above" another layer or another element can mean here and below that the one layer or the one element directly in direct mechanical and / or electrical contact is arranged on the other layer or the other element.

Furthermore, it can also mean that the one layer or the one element is arranged indirectly on or above the other layer or the other element. In this case, further layers and / or elements can then be arranged between the one or the other layer or between the one or the other element.

By "light" is meant here and below electromagnetic radiation which is in an ultraviolet to infrared and especially in a visible

Spectral range is. Light can thus preferably have spectral components in a blue to red wavelength range.

In an embodiment, the first and / or the second electrode comprises a first metallic layer and a barrier layer. The barrier layer is between the first metallic layer and the organic layer stack arranged.

The fact that a layer or an element "is arranged between two other layers or elements" can mean here and in the following that the one layer or the one

Element directly in direct mechanical and / or

electrical contact or in indirect contact with one of the two other layers or elements and in direct

mechanical and / or electrical contact or electrical or in indirect contact with other layers or

Elements is arranged. It can with indirect

Contact then further layers and / or elements between the one and at least one of the two other layers

or between the one and at least one of the two other elements.

According to one embodiment, the barrier layer comprises a material selected from a group comprising an inorganic metal oxide, nitride and / or carbide or an organic material.

The barrier layer is configured to form a barrier between the first metallic layer and the organic layer stack. In particular, the

Barrier layer to a possible migration of the metal of the first metallic layer or a

Interaction or reaction of the metal of the first

prevent metallic layer with the organic layer stack. As a result, a degradation of the organic layer stack caused by the metal of the first metallic layer is prevented or largely prevented be prevented which leads to a prolonged life of the organic light emitting diode.

Furthermore, it is possible through the barrier layer, the

Energy losses caused by the excitation of plasmons

arise, significantly reducing. As a result, the required power, which is necessary to achieve a specific luminance, can be reduced. Under a plasmon, a charge carrier density vibration at the interface of a metallic electrode or a metallic

Layer of an electrode and an adjacent dielectric, so an organic layer understood. The organic layer may be, for example, the organic light-emitting layer or a carrier injection layer of the

be organic layer stack. By the emitted

Radiation can be free charge carriers, in particular

Electrons, in a metallic electrode or in a metallic layer of an electrode

Charge carrier vibrations are excited. This part of the emitted radiation goes through the excitation

lost and therefore can no longer from the organic

LED are coupled outwards. In particular, plasmon (precise surface plasmon polaritons) designate longitudinal charge carrier density oscillations which occur parallel to the plane of extent of a surface of a metallic electrode or of a surface of a metallic layer of an electrode on this surface. Surface plasmons can in this case in particular at the surface of the organic light-emitting layer facing this

metallic electrode are generated. By the

Barrier layer is the distance of the first metallic layer to the organic layer stack, in particular to increases the organic light-emitting layer and thus reduces the energy transfer and thus the excitation of plasmons or suppressed. In one embodiment, the barrier layer is in direct mechanical contact with the organic layer stack.

According to one embodiment, the first and / or second electrode consists of the barrier layer and the first metallic layer. In this embodiment, there is thus direct mechanical contact between the barrier layer and the first metallic layer.

The first electrode as used herein may firstly be an anode. In this embodiment, the second electrode is formed as a cathode.

It is also possible that the second electrode is an anode and the first electrode is a cathode.

Cathode means the negatively charged electrode, the

is permanently connected to a first electrical connection at least during operation and receives electrons via this first electrical connection.

Anode means the positively charged electrode which, at least during operation, is permanently connected to a second electrical connection and receives positive charge carriers (holes) via this second electrical connection.

In the organic light emitting diode, for example, a

Electrode should be transparent and the other reflective. The organic light-emitting diode can thus be embodied either as a bottom emitter or as a top emitter. Alternatively, both electrodes can be made transparent. If both electrodes are transparent, the light-emitting diode can be referred to as a transparent OLED. By "transparent" is here and below referred to a layer that is transparent to visible light, especially for light that is in operation of the organic

Light emitting diode is generated in the organic layer stack. In this case, a transparent layer can be clear translucent. Particularly preferably, a layer designated here as transparent has the lowest possible absorption of light.

In one embodiment, the second electrode comprises or consists of a first metallic layer and a barrier layer. The barrier layer is over the organic layer stack and the first metallic layer is over the barrier layer. The second electrode may in this embodiment as a cathode

be educated.

In an embodiment, the first electrode comprises or consists of a first metallic layer and a barrier layer. The barrier layer is over the first metallic layer and the organic one

Layer stack is arranged above the barrier layer. The first electrode may be formed as an anode in this embodiment. In one embodiment, the first metallic contains

Layer of silver. In one embodiment, the first metallic layer is silver or silver and another metal. In one embodiment, the further metal is made

Magnesium, germanium, nickel, indium, gallium and / or

Aluminum selected. Preferably, the further metal is selected from magnesium and / or aluminum.

In one embodiment, the first metallic

Layer of silver, silver and magnesium, silver and

Germanium, silver and nickel, silver and indium, silver and gallium or silver and aluminum, preferably from silver, silver and magnesium or silver and aluminum.

In one embodiment, the first layer is at least 80% by weight of silver, for example, 88% by weight. For example, the first metallic layer consists of 88% by weight of silver and 12% by weight of magnesium or

Aluminum.

In one embodiment, the first metallic layer has a layer thickness between 7 nm and 1000 nm. If the first and / or second electrode is transparent, the first metallic layer has a layer thickness

between 7 and 50 nm, for example 16 nm. If the first or second electrode is designed to be reflective, then the first metallic layer has a layer thickness

between 50 and 1000 nm, preferably between 150 and 300 nm.

Is the first and / or second electrode reflective

formed, the first metallic layer is preferably made of silver, silver and magnesium or silver and aluminum, more preferably of silver. Silver has one

Reflectivity for light in the visible range of the electromagnetic spectrum, for example between 450 nm to 800 nm of about 95 percent. By this high

Reflectivity, the efficiency of the organic light emitting diode can be significantly increased because absorption losses are kept low. In addition, it is possible through the barrier layer, an interaction of the silver or an undesirable reaction of the layers of the organic

Layers stack with the silver of the first metallic

Layer to suppress or largely to

suppress, which contributes to an extension of the life of the light emitting diode. Thus, both a light emitting diode with high efficiency and high lifetime can be obtained.

Experiments show that the life with the

According to the invention, the first and / or second electrode can be increased by up to 20% while maintaining or improving the optoelectronic characteristics such as optical efficiency, current efficiency, external quantum efficiency and the threshold voltage. Furthermore, no shift of the color locus of the radiation emitted by the organic light emitting diode is observed.

In one embodiment, the first and / or the second electrode is arranged on a substrate. Is the first and / or second electrode transparent

formed, the substrate may be a steel foil.

According to one embodiment, the barrier layer has a layer thickness between 1 atomic layer or molecular layer and 20 nm. The barrier layer preferably has a layer thickness between 3 nm and 7 nm, for example 3 nm. With these layer thicknesses of the barrier layer, it is possible to use a

Interaction of the metal of the first metallic layer to prevent with the organic layer stack or to prevent a reaction between the metal of the first metallic layer and the organic layer stack and to suppress a Plasmonenanregung

or reduce. Thus, the life of the organic light emitting diode compared to light emitting diodes in which the metallic electrode is in direct mechanical contact with the organic layer stack can be significantly increased. In addition, the optoelectronic data of the organic light-emitting diode are not or only slightly influenced by these thin layer thicknesses.

In one embodiment, the barrier layer is formed of an insulating material and is in particular made of an insulating material. Due to the small layer thickness of the barrier layer, it is possible that a tunnel contact between the first metallic layer and the organic layer stack, in particular with a

Charge carrier injection layer of organic

Layer stack is formed. As a result, charge carriers, ie holes or electrons, the barrier layer

Tunnel through, so wander through.

In one embodiment, the barrier layer is formed of or consists of a conductive material

conductive material, such as aluminum zinc oxide. In this embodiment, at the side surfaces of the organic layer stack prior to application of the

Barrier layer be masked around a

Applying the barrier layer on the side surfaces of the organic layer stack to prevent. This can cause short circuits between the first and second electrodes be prevented. For masking, for example, a shadow mask made of stainless steel can be used.

By applying a shadow mask, short circuits between the first and the second electrode can be prevented, in particular in the case of a barrier layer composed of a conductive material, which is applied, for example, via an ALD method, at the edge regions of the organic light-emitting diode.

According to one embodiment, the first or the second electrode comprises a second metallic layer.

In one embodiment, the second electrode comprises or consists of a second metallic layer, a first metallic layer and a barrier layer.

The second metallic layer is above the organic one

Layer stack arranged, the barrier layer is above the second metallic layer and the first metallic

Layer is disposed over the barrier layer. The second

Electrode may be preferred in this embodiment as

Cathode be formed.

In one embodiment, the first electrode comprises or consists of a second metallic layer, a first metallic layer and a barrier layer.

The barrier layer is arranged above the first metallic layer, the second metallic layer is above the first metallic layer

Barrier layer arranged and the organic layer stack is disposed over the second metallic layer. The first electrode may be preferred in this embodiment as

Anode be formed. According to one embodiment, the first and / or the second electrode consists of the first metallic layer, the barrier layer and the second metallic layer. In an embodiment, the second metallic layer has direct contact with the organic layer stack.

In one embodiment, the barrier layer is disposed between the first and second metallic layers.

The second metallic layer is next to the

Barrier layer as a barrier between the first metallic layer and the organic layer stack. In particular, an interaction of the metal of the first metallic layer or a reaction of the metal of the first metallic layer with the organic layer stack is prevented. The second metallic layer can serve as well as protective layer. For example, it may be the organic

Layer stacks protect against damaging influences of subsequent application processes. For example, the organic layer stack can be protected from water pulses of an ALD method ("atomic layer deposition") for depositing the barrier layer.

In one embodiment, the second metallic layer is transparent. Due to the transparent formation of the second metallic layer, the second metallic layer absorbs

Layer hardly light, so that this layer does not adversely affect the luminance of the organic light emitting diode. According to one embodiment, the second metallic layer consists of silver and magnesium, aluminum, magnesium,

Germanium, nickel or copper. The second metallic layer preferably consists of aluminum.

In one embodiment, the second metallic layer has a layer thickness between an atomic layer and 20 nm,

preferably between 1 to 7 nm. With these layer thicknesses it can be guaranteed that the second metallic layer is transparent. Through the transparent

Forming the second metallic layer, the second metallic layer hardly absorbs light. As a result, the optoelectronic data of the organic light-emitting diode are not or only slightly influenced.

In an embodiment, the barrier layer comprises or consists of an inorganic metal oxide, nitride, and / or carbide. According to one embodiment, the inorganic metal oxide, nitride and / or carbide is selected from the group consisting of alumina, silica, silicon carbide, silicon nitride, silicon oxynitride, titanium oxide, zinc oxide, zirconium oxide,

Hafnium oxide, aluminum zinc oxide and combinations thereof. Alumina, silica, silicon carbide,

Silicon nitride, silicon oxynitride, titanium oxide, zinc oxide,

Zirconium oxide and hafnium oxide are insulating. Preferably, the inorganic metal oxide, nitride and / or carbide is selected from the group consisting of alumina, silica, silicon carbide, silicon nitride, silicon oxynitride, titania, zinc oxide, zirconia, hafnia, and combinations thereof. For example, the barrier layer is made

A1 ₂ 0 ₃ . In one embodiment, the barrier layer comprises an organic material or consists of an organic material

Material. The organic material may be selected from electron or hole transporting organic materials.

According to one embodiment, this is

Electron-transporting material of the barrier layer selected from a group comprising NET-18, 2, 2 ', 2 "- (1,3,5-benzene triyl) tris (1-phenyl-1H-benzimidazole), 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1, 3, 4-oxadiazole, 2, 9-dimethyl-4,7-diphenyl-l, 10-phenanthroline (BCP), 8-hydroxyquinolinolato-lithium, 4- (naphthalene -l-yl) -3,5-diphenyl-4H-1,2,2,4-triazole, 1,3-bis [2- (2,2'-bipyridine-6-yl) -1,3,4-oxadiazo -5-yl] benzene, 4,7-diphenyl-l, 10-phenanthroline (BPhen), 3- (4-biphenylyl) -4-phenyl-5-tert-butylphenyl-1,2,2,4-triazole, bis ( 2-methyl-8-quinolinolates) -4-

(phenylphenolato) aluminum, 6, 6 'bis [5- (biphenyl-4-yl) -1,3,4-oxadiazo-2-yl] -2,2' -bipyridyl, 2-phenyl-9, 10 di (naphthalen-2-yl) -anthracene, 2,7-bis [2- (2,2'-bipyridine-6-yl) -1,3,3-oxadiazo-5-yl] -9,9-dimethylfluorene , 1, 3-bis [2- (4-tert-butylphenyl) -1,3,4-oxadiazo-5-yl] benzene, 2- (naphthalen-2-yl) -4,7-diphenyl-l, 10 phenanthroline, 2,9-bis (naphthalen-2-yl) -4,7-diphenyl-l, 10-phenanthroline, tris (2,4,6-trimethyl-3- (pyridin-3-yl) phenyl) borane , 1-methyl-2- (4- (naphthalen-2-yl) phenyl) -1H-imidazo [4,5-f] [1,10] phenanthroline, phenyldipyrenylphosphine oxides, naphthalenetetracarboxylic dianhydride and its imides, perylenetetracarboxylic dianhydride and its imides , Materials based on silanols with a Silacyclopentadieneinheit and mixtures of the aforementioned substances. In one embodiment, the hole-transporting material of the barrier layer is selected from a group comprising HAT-CN, F16CuPc, LG-101, α-NPD, NPB (N, N'-bis (naphthalen-1-yl) -N, -bis (phenyl) benzidine), beta-NPB N, N'-bis (naphthalen-2-yl) -Ν, Ν'-bis (phenyl) benzidine), TPD (N, N'-bis (3-methylphenyl) -N, '-bis (phenyl) -benzidine), spiro TPD (Ν, Ν'-bis (3-methylphenyl) -N,' -bis (phenyl) -benzidine), spiro-NPB (N, '-Bis ( naphthalene-1-yl) -N, '-bis (phenyl) -spiro), DMFL-TPD N,' -Bis (3-methylphenyl) -N, '-bis (phenyl) -9, 9-dimethyl-fluorene) , DMFL-NPB (N, N'-bis (naphthalen-1-yl) -N, N'-bis (phenyl) -9, 9-dimethyl-fluorene), DPFL-TPD (N, N'-bis (3 - methylphenyl) -N, '-bis (phenyl) -9, 9-diphenyl-fluorene), DPFL-NPB (Ν, Ν'-bis (naphthalen-1-yl) -Ν, Ν'-bis (phenyl) - 9, 9-diphenyl-fluorene), spiro-TAD (2, 2 ', 7, 7'-tetrakis (N, N-diphenylamino) -9,9'-spirobifluorene), 9, 9-bis [4- (N , N-bis-biphenyl-4-yl-amino) -phenyl] -9H-f 9,9-bis [4- (N, N-bis-naphthalen-2-yl-amino) -phenyl] -9H-fluorene, 9,9-bis [4- (N, N'-bis-naphthalene) 2-yl-N, '-bis-phenyl-amino) -phenyl] -9H-fluoro, N, N'-bis (phenanthrene-9-yl) -N,' -bis (phenyl) -benzidine, 2, 7 -Bis [N, N-bis (9,9-spiro-bifluoren-2-yl) -amino] -9,9-spiro-bifluorene, 2,2'-bis [N, N-bis (biphenyl-4-) yl) amino] 9,9-spiro-bifluorene, 2,2'-bis (N, -di-phenyl-amino) 9,9-spirobifluorene, di- [4- (N, N-ditolyl-amino) -phenyl] cyclohexane, 2, 2 ', 7, 7' -tetra (N, N-di-tolyl) amino-spiro-bifluorene, N,, ',' -tetra-naphthalen-2-yl-benzidine and mixtures of these Compounds includes.

In an embodiment, the second electrode comprises a first metallic layer and a barrier layer. The second electrode may preferably be formed as a cathode. The first electrode may be used according to this embodiment as

Anode may be formed and may consist of a Locherinjizierenden material. As a hole-injecting material, any hole-injecting one known in the art may be used Material used. If the radiation-emitting device is designed, for example, as a "bottom emitter" or as a transparent OLED, then the anode is formed

for example, made of a transparent material.

For example, it may consist of transparent conductive oxides, or comprise a layer thereof. These transparent conductive oxides ("TCO") include metal oxides such as zinc oxide, tin oxide, cadmium oxide, titanium oxide, indium oxide or

Indium tin oxide, Zn2SnOzi, CdSnO3, ZnSnO3, Mgln20zi, GalnO3, ηηΐη2θ5 or In4Sn30) _2, or mixtures of different transparent conductive oxides, are, however, not limited thereto. The TCOs are not necessarily subject to a stoichiometric composition and may also be p- or n-doped.

In an embodiment, the first electrode comprises a first metallic layer and a barrier layer. The first electrode may preferably be formed as an anode. The second electrode may be used according to this embodiment as

Cathode can be molded and can be made from one

consist of electron-injecting material. When

Cathode materials may also contain one or more of the TCOs mentioned in the anode materials, or the cathode may also consist entirely of one of these materials. The cathode can also

be transparent.

According to one embodiment, the organic

Layer stack at least one organic light-emitting layer in the form of an organic electroluminescent layer, which is adapted to be in a Operating state of the organic light to light

produce .

Suitable materials for the organic light-emitting layer are materials which have a radiation emission due to fluorescence or phosphorescence, for example polyfluorene, polythiophene or polyphenylene or derivatives, compounds, mixtures or copolymers thereof. Of the

organic functional layer stack can also be one

Have a plurality of organic light-emitting layers, which are arranged between the first and the second electrode. For example, the organic light emitting diode emits white light. The organic layer stack may comprise layers with organic polymers, organic oligomers, organic monomers, organic small, non-polymeric molecules ("small molecules") or combinations thereof

For example, organic functional layer stacks may be in addition to the organic light emitting layer

Charge carrier injection layers,

Charge carrier transport layers and / or

Have charge carrier blocking layers. Materials for charge carrier injection layers,

Charge carrier transport layers and / or

Charge carrier blocking layers are known to the person skilled in the art.

According to a further embodiment, the organic light-emitting diode has a substrate on which the electrodes and the organic layer stack are applied. The substrate may for example comprise one or more materials in the form of a layer, a plate, a foil or a laminate, which are selected from steel, glass, quartz, Plastic, metal, silicon wafers. Particularly preferably, the substrate glass or / and plastic, for example in the form of a glass layer, glass sheet, glass plate, plastic layer, plastic film, plastic plate or a glass-plastic laminate, on or is therefrom. In addition, the substrate, for example, in the case of plastic as the substrate material, one or more barrier layers have, with which the plastic material is sealed. In one embodiment, the first electrode is disposed above the substrate and is preferably in contact therewith

direct mechanical contact. In this embodiment, the second electrode is disposed over the first electrode. Over the electrodes and the organic layer stack, preferably over the second electrode, a

Encapsulation arrangement, for example a

Thin-film encapsulation, be arranged, which protects the electrodes and the organic layer stack from harmful external

Influences such as moisture, oxygen,

Hydrogen sulfide or other substances can protect.

Preferably, the encapsulation arrangement is in direct

mechanical contact with the second electrode. With regard to the basic structure of an organic light-emitting component, in this case for example with regard to the structure, the layer composition and the materials of the substrate, the organic functional layer stack and the encapsulation arrangement, reference is made to the document WO 2010/066245 Al, which in particular Regarding the structure, the layer composition and the materials of the substrate, the organic layer stack and the encapsulation arrangement is hereby expressly incorporated by reference.

It is a process for producing an organic

LED indicated. All features specified under the organic light emitting diode may also be features of the method for producing the organic light emitting diode and vice versa.

According to one embodiment, the method comprises

Production of an organic light-emitting diode following

Process steps preferably in the order given:

A) providing a substrate,

B) applying a first electrode to the substrate,

C) Applying an organic layer stack to

Generation of light on the first electrode,

D) applying a second electrode on the organic layer stack.

According to one embodiment, method step D) comprises the following method steps:

D2) applying a barrier layer to the organic layer stack, wherein the barrier layer comprises a material or consists of a material selected from a group comprising an inorganic metal oxide, nitride and / or carbide or an organic material, D3) application a first metallic layer on the barrier layer.

According to one embodiment, method step B) comprises the following method steps:

Bl) applying a first metallic layer to the substrate, B2) Applying a barrier layer on the first

metallic layer, wherein the barrier layer comprises a material or consists of a material selected from a group comprising an inorganic metal oxide, nitride and / or carbide or an organic material.

According to one embodiment, method step D) comprises a method step D1):

D1) applying a second metallic layer on the organic layer stack.

According to one embodiment, method step B) comprises a method step D3):

B3) applying a second metallic layer on the barrier layer. Preferably, the second metallic layer is deposited directly on the barrier layer.

In one embodiment, the second metallic layer in process step Dl) directly on the organic

Layer stack applied.

In one embodiment, process step D2) follows after process step D1) and process step D3)

Process step D2). In particular, the

Process steps directly one after the other.

In one embodiment, the method comprises a further method step: E) applying a shadow mask to the side surfaces of the organic layer stack. This

Process step takes place in particular before process step D) and particularly preferably before process step D2). By applying a shadow mask before applying the barrier layer in step D2) can be prevented be that the barrier layer is deposited on the side surfaces of the organic layer stack.

In particular, when the barrier layer is formed of a conductive material, so in the organic

Light-emitting diode short circuits between the first and the second electrode can be prevented. Process step E) preferably takes place when the barrier layer in

Process step D2) is applied by means of ALD. According to one embodiment, the first metallic

Layer in process step D3) or Bl) means

physical vapor deposition (PVD, physical vapor deposition), knife coating, screen printing or inkjet, preferably applied by physical vapor deposition.

According to one embodiment, the barrier layer is in

Process step B2) or D2) by means of chemical

Chemical vapor deposition (CVD), molecular vapor deposition (MVD), molecule vapor

deposition "), atomic layer deposition (ALD," atomic layer deposition "), molecular layer deposition (MLD) or sputtering.

According to one embodiment, the second metallic

Layer in process step Dl) or B3) by means of

physical vapor deposition or sputtering

applied.

In one embodiment, method step D1) takes place when the barrier layer is applied in method step D2) by means of ALD. For example, the organic layer stack can be protected from water pulses of this method. In one embodiment, in step D3) or Bl) silver is deposited or silver and magnesium, silver and aluminum, silver and germanium, silver and nickel, silver and indium or silver and gallium are deposited simultaneously.

Further advantages, advantageous embodiments and

Further developments emerge from the following in

Compound described with the figures

Embodiments.

Figures 1 and 2 show schematic side views of

Embodiments of organic light emitting diodes described herein;

FIG. 3 shows life curves of an exemplary embodiment of an organic light-emitting diode described here in comparison with a reference. In the embodiments and figures, the same, similar or equivalent elements each with

be provided with the same reference numerals. The illustrated elements and their proportions with each other are not to be regarded as true to scale, but individual elements, such as layers, components, components and areas, for better presentation and / or better understanding may be exaggerated.

FIG. 1 shows an exemplary embodiment of an organic light-emitting diode 1. The light-emitting diode 1 comprises a substrate 5, for example a glass substrate. On the substrate 5, a first electrode 2 is arranged. The first electrode 2 is formed as an anode and consists for example of ITO. On The first electrode 2 is arranged an organic layer stack 3 for generating light. The organic one

Layer stack 3 has a planar configuration and has an organic light-emitting layer (not shown here) for generating light. The organic layer stack 3 may also include a plurality of organic light-emitting layer for generating light of different or the same

Have wavelengths. Next, the organic

Layer stack 3 electron transporting,

electron injecting, hole transporting and

include hole injecting layers. Materials for these layers are known in the art. It is also possible that a charge carrier generating layer is arranged between two organic light-emitting layers. Above the organic layer stack 3, a second electrode 4 is arranged. The second electrode 4 is a cathode

educated. The second electrode comprises a

Barrier layer 42 of an insulating material such as

Silicon nitride. The barrier layer 42 is in direct contact with the organic layer stack 3 and completely covers the surface of the organic layer stack 3 facing away from the substrate 5. The barrier layer 42 has a layer thickness of 5 nm. Furthermore, the second electrode 4 comprises a first metallic layer 43 consisting of silver. Due to the small layer thickness of the barrier layer 42 is a tunnel junction between the first metallic

Layer 43 and the organic layer stack 3 formed. This allows electrons the barrier layer 42

Tunnel through, so wander through. The first metallic

Layer 43 is arranged over the entire surface over the entire surface of the barrier layer 42 facing away from the substrate 5 and has a thickness of 200 nm. This is the second one

4 electrode reflective for that in the organic light formed emitting layer of the organic layer stack 3 generated light. Thus, the light on the first electrode 2 and the substrate 5 to the environment

emitted and it is in this embodiment, the organic light emitting diode 1 is a bottom emitter. A first metallic layer 43 of silver has a reflectivity of 95% for visible light, which is much higher than, for example, a layer of aluminum. Thus, the effectiveness and the light output of the light emitting diode 1 are particularly high. The barrier layer 42 forms a barrier to an interaction or reaction of the silver of the first metallic layer 43 with the organic layer stack 3. Thus, little or no silver can penetrate into or onto the organic layer stack 3 during the lifetime of the organic light-emitting diode 1, and in particular there is no direct

mechanical contact between the silver of the first

metallic layer 43 and the organic layer stack 3. Thus, the silver can not damage the organic layer stack. In addition, a reaction of the silver at the interface of the organic layer stack can be prevented. This can be compared to LEDs without

Barrier layer 42 life can be increased. In addition, the excitation of plasmons on the surface of the first metallic layer 43 is largely suppressed by the barrier layer 42, so that to achieve a certain

Luminance a lower power is needed. With the organic light-emitting diode 1 of the present invention, it is thus advantageously possible to extend the service life and to achieve an improved yield of the emitted radiation and thus improved functionality and efficiency. In comparison to the light-emitting diode 1 according to FIG. 1, the light-emitting diode 1 according to FIG. 2 has a second metallic layer 41. The second metallic layer 41 is made

for example, made of aluminum and has a layer thickness of 4 nm. The second metallic layer 41 is disposed between the first metallic layer 43 and the barrier layer 42. The second metallic layer 41 covers the entire surface of the organic layer stack 3 facing away from the substrate 5. The second metallic layer 41 is transparent and serves as a protective layer of the organic layer stack 3, for example when the

Barrier layer 42 is deposited by means of an ALD method. FIG. 3 shows the life curves of an organic light-emitting diode according to the invention (curve with the reference symbol I) and that of a conventional organic light-emitting diode as a reference (curve with the reference symbol II). The time in h is plotted on the x-axis and the relative luminance on the y-axis. The LEDs are up to the second

Electrode identically constructed. The second electrode is each formed as a cathode and consists in the known, conventional light-emitting diode of the reference of a layer consisting of silver and magnesium, in direct

mechanical contact with the organic layer stack stands. In the organic light-emitting diode according to the invention, the cathode consists of a first metallic layer, a barrier layer and a second metallic layer. In this case, the second metallic layer is in direct mechanical contact with the organic layer stack and the barrier layer. The barrier layer is in direct mechanical contact with the first and second

metallic layer. Over the first metallic layer a thin-film encapsulation is arranged. The first

Metallic layer is made of silver and has a

Layer thickness of 200 nm. The barrier layer consists of Al ₂ O ₃ and has a layer thickness of 3 nm. The second metallic layer consists of aluminum and has a layer thickness of 3 nm. The organic layer stack consists in two light emitting diodes of a substrate, an anode of ITO, a hole transport layer, a

Electron blocking layer, an organic light

emitting layer, a hole blocking layer and an electron injection layer. Above the

Electron injection layer, the cathode is arranged and is in direct mechanical and electrical contact with this. The thin-film encapsulation covers the side surfaces of the organic layer stack. As can be seen, the organic light-emitting diode according to the invention shows a markedly less marked drop in relative luminance over time (curve I). For example, the light-emitting diode according to the invention still has a relative luminance of about 80% after 300 h (curve I), while the conventional organic light-emitting diode after 300 h hours only a relative luminance

Luminance of about 20%. The organic light-emitting diode according to the invention has a luminance (l _eff ) of 11.5 cd / A, while the reference has a luminance of 10.5 cd / A. The external quantum efficiency is 7.19% for the inventive light-emitting diode and 6.04% for the reference.

The invention is not limited by the description based on the embodiments of these. Rather, the invention encompasses any novel feature as well as any combination of features, including in particular any combination of features in the claims, even if this feature or that combination itself is not explicit in the

Claims or embodiments is given.

This patent application claims the priority of German Patent Application 10 2015 119 772.3, the disclosure of which is hereby incorporated by reference.

Reference sign

1 organic light emitting diode

2 first electrode

3 organic layer stacks

4 second electrode

5 substrate

41 second metallic layer

42 barrier layer

43 second metallic layer t time

h hour

I life curve

II life curve

L relative luminance

Claims

Organic light-emitting diode (1) comprising

a first electrode (2),

an organic layer stack (3) for generating light, which is arranged above the first electrode (2),

- A second electrode (4) which is disposed over the organic layer stack (3), wherein

- The first electrode (2) is formed as an anode and transparent and the second electrode (4) is designed to be reflective as a cathode and consists of a first metallic layer (43), a barrier layer (42) and a second metallic layer (41) .

- The second metallic layer (41) above the

organic layer stack (3), the barrier layer

(42) over the second metallic layer (41) and the first metallic layer (43) over the barrier layer

(42) is arranged

the first metallic layer contains silver and has a layer thickness between 50 and 1000 nm,

- The second metallic layer has a layer thickness between an atomic layer and 20 nm and

- The barrier layer (42) comprises a material which is selected from a group which is an inorganic

Metal oxide, nitride and / or carbide or a

includes organic material.

2. Light-emitting diode according to claim 1, wherein the second metallic layer (41) of silver and magnesium, magnesium,

Germanium, nickel, copper or aluminum. Light-emitting diode according to one of the preceding claims, wherein the first metallic layer (43) made of silver or silver and another metal.

A light-emitting diode according to the preceding claim, wherein the further metal is selected from magnesium, germanium, nickel, indium, gallium and / or aluminum.

Light-emitting diode according to one of the preceding claims, wherein the barrier layer (42) has a layer thickness

between an atomic layer or molecule layer and 20 nm.

A light emitting diode according to any one of the preceding claims, wherein the barrier layer (42) is an inorganic one

Metal oxide, nitride and / or carbide selected from the group consisting of alumina,

Silicon oxide, silicon carbide, silicon nitride,

Silicon oxynitride, titanium oxide, zinc oxide, zirconium oxide, hafnium oxide, aluminum zinc oxide, and combinations thereof.

A light emitting diode according to any one of claims 1 to 5, wherein the barrier layer (42) comprises an organic material.

Method for producing an organic light-emitting diode (1) comprising the method steps:

A) providing a substrate (5),

B) applying a first electrode (2) on the

Substrate (5), wherein the first electrode (2) is formed as an anode and transparent, C) applying an organic layer stack (3) to generate light on the first electrode (2),

D) applying a second electrode (4) on the organic layer stack (3), wherein the second

Electrode (4) is designed as a cathode and reflective, and of a first metallic layer (43), a barrier layer (42) and a second

metallic layer (41),

wherein method step D) comprises the following method steps:

D1) application of a second metallic layer (41) with a layer thickness between an atomic layer and 20 nm on the organic layer stack (3),

D2) applying a barrier layer (42) on the second metallic layer (41), wherein the

Barrier layer (42) comprises a material selected from a group comprising an inorganic metal oxide, nitride and / or carbide or an organic material,

D3) applying a first metallic layer (43) with a layer thickness between 50 and 1000 nm on the barrier layer (42).

The method of claim 8, wherein the first metallic layer (43) is applied by PVD.

Method according to one of claims 8 to 9, wherein the barrier layer (42) by means of CVD, ALD, MVD, MLD or sputtering is applied.