Organic light-emitting device and method for producing an organic light-emitting device

Abstract

Organic light-emitting component (100) comprising an organic layer stack (S) between two electrodes (2, 3), wherein the organic layer stack (S) comprises a light-emitting layer (4) and the light-emitting layer (4) comprises a polymer and an emitter material, wherein - the emitter material is designed to generate electromagnetic radiation during operation of the component, - the transition dipole moments (11) of the radiation-generating transition of the molecules of the emitter material (10) have an anisotropic alignment within the light-emitting layer and <cos 2 Θ> less than 1 / 3, where Θ is the angle between the respective transition dipole moment (11) of the radiation-generating transition of the molecules of the emitter material (10) and a layer normal (N) of the light-emitting layer (4), - the molecules of the emitter material (10) are bound to the polymer, - the polymer has linear polymer chains and the linear polymer chains are anisotropically aligned, and - the emitter material is a square planar transition metal complex and one or more molecules of the transition metal complex are bound to a linear polymer chain.

Description

An organic light-emitting component is specified. Furthermore, a method for producing an organic light-emitting component is specified.The following publications disclose organic light-emitting components: GB 2 535 698 A, US 2003 / 0 027 017 A1, EP 1 424 350 A1.In the case of organic light-emitting components, such as organic light-emitting diodes (OLEDs), only a portion of the electromagnetic radiation generated in the light-emitting layer is coupled out to the outside to the environment. The remaining part of the radiation distributes itself to different loss channels, for example to radiation which is guided in the substrate or in organic layers by waveguiding effects, and surface plasmons which can be generated in a metallic electrode. The waveguiding effects are produced in particular by refractive index differences at the boundary surfaces of the individual layers and to the ambient air of an OLED. Usually, the external quantum efficiency is approximately 22% with an assumed internal quantum efficiency of 100%, i.e. only approximately a quarter of the generated radiation is coupled out to the environment, while the remainder is lost due to waveguiding effects. The radiation guided in the loss channels cannot be coupled out from an organic light-emitting component, in particular without technical measures.An object to be achieved is to provide an organic light-emitting component which has increased efficiency and light decoupling and emits radiation with an increased degree of polarization. A further object is to specify a method for producing an organic light-emitting component.The objects are achieved by the organic light-emitting component and the method for producing an organic light-emitting component according to the independent claims.Advantageous embodiments and refinements of the present invention are specified in the respectively dependent claims.The organic light-emitting component has an organic layer stack between two electrodes. The organic layer stack comprises a light emitting layer. The light emitting layer comprises a polymer and an emitter material. The emitter material is configured to generate electromagnetic radiation during operation of the component.In one embodiment, the emitter material is configured to generate electromagnetic radiation in the visible range of the electromagnetic spectrum. In particular, the electromagnetic radiation generated is radiated to the outside to the environment.In one embodiment, the electromagnetic radiation is radiated to the outside via a radiation exit surface. The radiation exit surface is a main surface of the layer sequence. The radiation exit surface extends in particular parallel to a main extension plane of the layers of the layer sequence. With an assumed internal quantum efficiency of 100%, an external quantum efficiency of approximately 35% can be achieved according to the invention.In one embodiment, the emitter material comprises molecules of the emitter material.The molecules of the emitter material are bound to the polymer. In particular, the emitter material is covalently bonded to the polymer.In an embodiment, the emitter material is oriented or oriented in the light emitting layer. This means that the emitter material is arranged anisotropically, i.e. with a preferred direction in the light-emitting layer.According to an embodiment, the emitter material comprises molecules of the emitter material. The molecules of the emitter material each have a transition dipole moment of the radiation-generating transition.The transition dipole moment has a fixed direction in the coordinate system of the emitter material (molecular coordinate system). This means in particular that by aligning the emitter material in the light-emitting layer, i.e. in space, its transition dipole moment of the radiation-generating transition is also aligned.With regard to the term transition dipole moment, reference is made in particular to: "IUPAC. Compendium of Chemical Terminology, Second Edition (The "Gold Book"), 1997 or IUPAC. Compendium of Chemical Terminology, PAC, 2007, 79, 293 (Glossary of terms used in photochemistry, third edition (IUPAC Recommendations 2006))) on page 434, DOI: 10.1351 / goldbook.T06460. The disclosure content of the documents is incorporated by reference.In at least one embodiment, the transition dipole moments of the radiation-generating transition of the molecules of the emitter material have in total a preferred direction within the light-emitting layer and are thus aligned anisotropically in total.In at least one embodiment, the transition dipole moments of the radiation-generating transition of the molecules of the emitter material are arranged in total perpendicular to a layer normal of the light-emitting layer with a maximum deviation of + / -45° from this perpendicular orientation. The layer normal of the light-emitting layer here and below denotes a preferred direction which is arranged perpendicular to the light-emitting layer.The fact that the transition dipole moments of the molecules of the emitter material in total have anisotropic alignment within the light-emitting layer means here and below that the majority of the molecules of the emitter material have a preferred direction, i.e. in particular at least 50%, 60%, 70%, 80%, 90% or 95% and at most 100% of all molecules of the emitter material. Preferably, therefore, at least 50%, 60%, 70%, 80%, 90% or 95% and at most 100% of all molecules of the emitter material are arranged perpendicular to a layer normal of the light-emitting layer with a maximum deviation of + / -45° from this perpendicular orientation.In one embodiment, the emitter material or the molecules of the emitter material are oriented or aligned in the light-emitting layer. Oriented or oriented here and in the following means that the emitter material and / or the molecules of the emitter material and / or the transition dipole moment of the radiating transition of the molecules assume a preferred direction in the light-emitting layer. In particular, the transition dipole moments are arranged in total perpendicular to the layer normal of the light-emitting layer. The transition dipole moments of the molecules can alternatively or additionally be arranged in total with a deviation of up to + / -45°, for example + / -40°, + / -35°, + / -30°, + / -25°, + / -20°, + / -15°, + / -10° or + / -5° from this perpendicular orientation. In particular, on average all transition dipole moments of the radiating transitions of the molecules have a perpendicular arrangement of + / -45° to the layer normal of the light-emitting layer.The orientation factor K e= < cos 2 θ> can be used as a measure of the orientation of molecules. With regard to the term orientation factor, reference is made in particular to: IUPAC. Compendium of Chemical Terminology, PAC, 2007, 79, 293 (Glossary of terms used in photochemistry, third edition (IUPAC Recommendations 2006)), on page 371, DOI: 10.1351 / goldbook.MT07422. The disclosure content of the document is incorporated by reference.The fact that the transition dipole moments of the molecules of the emitter material have an anisotropic alignment overall means, in particular, that the orientation factor K e is less than 1 / 3. The angle θ is the angle between the respective transition dipole moment of the molecules of the emitter material and a layer normal N, wherein the layer normal N is arranged perpendicular to the light-emitting layer. The orientation factor K e is averaged over all molecules of the emitter material. Specifically, <cos 2 Θ> is less than 0.2; 0.1; 0.015; 0.001 or 0. In particular, the transition dipole moments are arranged in total perpendicular to the layer normal with a maximum deviation of + / - 45° from this perpendicular orientation.Due to these anisotropic transition dipole moments, which are arranged in particular perpendicular to a layer normal of the light-emitting layer, the radiation generated by the dipole transition also has a preferred direction and thus an anisotropy. Furthermore, the radiation is polarized, i.e. it has a higher degree of polarization than unpolarized radiation. The radiation emitted by the emitter material is preferably emitted with a polarization direction parallel to the transition dipole moment. In particular, the generated radiation impinges on the radiation exit surface at an angle perpendicular or nearly perpendicular to the radiation exit surface. As a result, total reflection at the boundary surface with the ambient air as well as waveguiding effects can be significantly reduced. This provides an organic light-emitting component with increased coupling-out of light and thus increased efficiency. Polarization of the radiation may be important, for example, when using the organic light-emitting component in a display. If the generated radiation is already polarized, the use of polarization filters can be dispensed with and the entire generated radiation can thus be used without filtering.According to at least one embodiment, all molecules of the emitter material have a transition dipole moment which is arranged in a perpendicular orientation to the layer normal of the light-emitting layer with a maximum deviation of + / -45° from this perpendicular orientation, for example 30°.According to at least one embodiment, at least 50% or 60% or 70% or 80% or 90% or 95% of all molecules of the emitter material have a transition dipole moment of the radiation-generating transition which is arranged perpendicular to the layer normal of the light-emitting layer with a maximum deviation of + / -45° from this perpendicular orientation.According to at least one embodiment, the organic light-emitting component is an organic light-emitting diode (OLED).According to one embodiment, the organic functional layer stack comprises, in addition to the light-emitting layer, a plurality of organic functional layers selected from further light-emitting layers, hole-injecting layers, hole-transporting layers, electron-injecting layers, electron-transporting layers, hole-blocking layers and electron-blocking layers. Materials for these layers are known to the skilled person.According to at least one embodiment, the organic light-emitting component has at least two electrodes, between which the organic layer stack is arranged.According to at least one embodiment, at least one of the electrodes is transparent. Transparent here and in the following denotes a layer which is transparent to visible light. The transparent layer can be clear, translucent or at least partially light-scattering and / or partially light-absorbing, so that the transparent layer can also be diffuse or milky translucent, for example. Particularly preferably, a layer referred to here as transparent is as light-transmissive as possible, so that in particular the absorption of electromagnetic radiation generated in the first light-emitting layer during operation of the component is as low as possible.According to at least one embodiment, both electrodes are transparent. The light generated in the first light-emitting layer can thus be emitted in both directions, i.e. through both electrodes. In the case where the organic light-emitting component has a substrate, this means that the radiation can be emitted both through the substrate, which is then likewise transparent, and in the direction facing away from the substrate.Furthermore, in this case, all layers of the organic light-emitting component can be transparent, with the result that the organic light-emitting component forms a transparent OLED. In addition, it may also be possible for one of the two electrodes, between which the organic functional layer stack is arranged, to be selected such that it is not transparent and preferably reflective, such that light generated in the first light-emitting layer between the two electrodes can be emitted through the transparent electrode only in one direction. If the electrode arranged on the substrate is transparent and the substrate is also transparent, it is also referred to as a bottom emitter, while if the electrode arranged facing away from the substrate is transparent, it is referred to as a top emitter.As a material for a transparent electrode, for example, a transparent conductive oxide may be used. Transparent conductive oxides (TCO: "transparent conductive oxides") are transparent conductive materials, generally metal oxides such as, for example, zinc oxide, tin oxide, cadmium oxide, titanium oxide, indium oxide, indium tin oxide (ITO) or aluminum zinc oxide (AZO). Besides binary metal oxygen compounds such as ZnO, SnO 2 or In 2 O 3 ternary metal oxygen compounds such as Zn 2 SnO 4, CdSnO 3, ZnSnO 3, MgIn 2 O 4, GaInO 3, also belong, Zn 2 In 2 O 5 or In 4 Sn 3 O 12 or mixtures of different transparent conductive oxides to form the group of TCOs. Furthermore, the TCOs do not necessarily correspond to a stoichiometric composition and can also be p- or n-doped.According to one embodiment, the component has at least one metallic electrode. The metal may be selected from a group comprising aluminum, barium, indium, silver, gold, magnesium, calcium, and combinations thereof and alloys. In particular, the metallic electrode is formed from silver, gold, aluminum or alloys with these metals, for example Ag:Mg or Ag:Ca. Depending on the selected layer thickness, the metallic electrode can be reflective or transparent.By arranging the transition dipole moments of the radiation-generating transition of the molecules of the emitter material perpendicular to the layer normal of the light-emitting layer, the loss of the generated radiation due to plasmon excitation is prevented or at least largely prevented.A plasmon is understood to mean a charge carrier density oscillation at the interface of a metallic electrode and an adjoining dielectric, that is to say an organic layer. By means of the radiation generated, free charge carriers, in particular electrons in the metallic electrode, can be excited to charge carrier density oscillations. A portion of the generated radiation is thus lost as a result of the excitation and can therefore no longer be coupled out to the outside of the organic light-emitting component. Plasmons in particular denote longitudinal charge carrier density oscillations which occur parallel to the plane of extent of a surface of a metallic electrode on this surface. Plasmons are excited by radiation that results from transitions with a transition dipole moment that is oriented parallel to the layer normal of the first light-emitting layer. As a result of the perpendicular alignment or the largely perpendicular alignment of the transition dipole moments of the molecules of the emitter material to the layer normal of the first light-emitting layer, the plasmon excitation can thus be suppressed or largely suppressed. As a result, the proportion of radiation decoupled from the outside to the environment can be increased.According to one embodiment, the organic light-emitting component comprises a substrate. In particular, one of the two electrodes is arranged on the substrate. The substrate can have, for example, one or more materials in the form of a layer, a plate, a film or a laminate selected from glass, quartz, plastic, metal, silicon wafer. In particular, the substrate comprises or consists of glass.In one embodiment, the organic light-emitting component has a second light-emitting layer. The light emitting layers may be vertically stacked. Thus, higher efficiency can be achieved by using a plurality of vertically stacked light emitting layers. The light-emitting layers stacked one above the other can be connected to one another by a charge generation layer sequence (CGL). As a result, it may be possible to generate a plurality of photons per charge carrier pair which is injected in such a stack, since the charge carrier generation layers of the charge carrier generation layer sequence act like internal anodes and cathodes. In particular, the charge carrier generation layer sequence comprises an electron transporting layer, an intermediate layer and a hole transporting layer.The structure and the materials of a charge carrier generation layer sequence which is arranged between two light-emitting layers are disclosed in the patent application DE 102015114084.5, which is hereby incorporated in its entirety by reference in this respect.All features mentioned for the light-emitting layer can also apply to the further light-emitting layers.In one embodiment, the emitter material is present at 1 to 20 mass percent, preferably at 1 to 10 mass percent, preferably at 1 to 5 mass percent, with respect to the total mass of polymer and emitter material in the light-emitting layer.In one embodiment, the molecules of the emitter material are bonded to the polymer via at least one functional group. In particular, the light-emitting layer is produced from a functionalized polymer and a functionalized emitter material. A reaction of the functionalized polymer and the functionalized emitter material produces a functional group via which the emitter material is bonded to the polymer in the light-emitting layer.According to one embodiment, the functional group via which the molecules of the emitter material are bonded to the polymer comprises an ester, ether, amide, hydroxy or ether group.In one embodiment, the polymer is a linear polymer. The polymer comprises linear polymer chains. In particular, the polymer comprises linear polymer chains formed by carbon-carbon bonds. In other words, the polymer has in particular a basic structure comprising carbon-carbon bonds. Linear polymer chains are understood here and below to mean that the polymer chains are not branched. In particular, the light-emitting layer is made of a linear functionalized polymer.In one embodiment, the polymer, in particular the linear polymer chains, is oriented or oriented in the light-emitting layer. This means that the polymer or the linear polymer chains are arranged anisotropically, i.e. with a preferred direction in the light-emitting layer.In one embodiment, the linear polymer chains in the light-emitting layer are arranged parallel or substantially parallel to one another. The fact that the linear polymer chains are arranged substantially parallel to one another means here and below a deviation of + / -45°, + / -35°, + / -30°, + / -25°, + / -20°, + / -15°, + / -10° or + / -5° from this parallel arrangement. In particular, the linear polymer chains are arranged parallel or substantially parallel to the radiation exit surface.In one embodiment, the light emitting layer is made of a functionalized polymer and a functionalized emitter material, wherein the functionalized polymer comprises linear polymer chains substituted with pendant groups. The fact that the polymer chains are substituted by pendant groups means that hydrogen atoms of the functionalized polymer are partially substituted by a pendant group. The pendant groups include epoxy, hydroxy, carbonyl, carboxyl, triflate, tosylate, iodide, bromide or chloride groups, preferably epoxy, hydroxy, carbonyl or chloride groups. The carbonyl groups are in particular aldehyde or keto groups. The functionalized emitter material is functionalized with a functional group comprising an amine group, an alcoholate or an acid chloride. By a reaction of the side groups of the linear polymer chains of the functionalized polymer with the functional groups of the functionalized emitter material, the emitter material is covalently bonded to the polymer or the linear polymer chains. In particular, the molecules of the emitter material are bonded to the polymer via at least one functional group comprising an ester, ether, amide, hydroxy or ether group.The functional groups can be bonded to the functionalized emitter material or the functionalized polymer via a spacer, preferably an aryl or alkyl group, such as a phenyl, methyl, ethyl or propyl group.In one embodiment, the light emitting layer is made of a functionalized polymer comprising linear polymer chains having pendant hydroxyl groups and a functionalized emitter material functionalized with at least one acid chloride group. The hydroxy side chain reacts with the acid chloride group of the functionalized emitter material to form an ester group. The emitter material is then bonded to the polymer in the light-emitting layer via an ester group.In one embodiment, the light emitting layer is made of a functionalized polymer comprising linear polymer chains with pendant epoxy groups and a functionalized emitter material functionalized with at least one amine or alcoholate group. Ring opening of the epoxide produces a hydroxyl group and an ether group via which the emitter material is bonded to the polymer, or a hydroxyl group and an amine group via which the emitter material is bonded to the polymer.In one embodiment, the light-emitting layer is produced from a functionalized polymer comprising linear polymer chains having carbonyl, in particular aldehyde or keto side groups and a functionalized emitter material functionalized with at least one amine or alcoholate group. The emitter material is bonded to the polymer by the nucleophilic addition and optionally subsequent condensation.In one embodiment, the light emitting layer is made of a functionalized polymer comprising linear polymer chains with chloride side groups and a functionalized emitter material functionalized with at least one amine or alcoholate group. A nucleophilic substitution forms an amine group or an ether group via which the emitter material is bonded to the polymer.In one embodiment, the light emitting layer is made of a functionalized polymer selected from polyethylene, polycarbonate, polymethylmethacrylate, polystyrene, and silicone. The functionalized polymers are substituted with pendant groups comprising epoxy, hydroxy, carbonyl, carboxyl, triflate, tosylate, iodide, bromide or chloride groups, preferably epoxy, hydroxy, carbonyl or chloride groups. The fact that the functionalized polymers are substituted with pendant groups means in particular that hydrogen atoms of the polymer chain are partially substituted by pendant groups comprising epoxy, hydroxy, carbonyl, carboxyl, triflate, tosylate, iodide, bromide or chloride groups, preferably epoxy, hydroxy, carbonyl or chloride groups. More particularly, it is a polyethylene substituted with pendant groups comprising epoxy, hydroxy, carbonyl, carboxyl, triflate, tosylate, iodide, bromide or chloride groups, preferably epoxy, hydroxy, carbonyl or chloride groups. It is preferably a polyethylene having pendant groups comprising or consisting of hydroxyl groups.According to one embodiment, the molecules of the emitter material are each bonded to the linear polymer chains via two functional groups. In this case, one or more molecules of the emitter material can each be bonded via two functional groups to a linear polymer chain, or one or more molecules of the emitter material can be bonded via two functional groups to a linear polymer chain and to a further polymer chain.In one embodiment, one or more molecules of the emitter material are each bonded to a linear polymer chain via two functional groups. Preferably, in each case one molecule of the emitter material is bonded via two functional groups to in each case one linear polymer chain.According to one embodiment, one or more molecules of the emitter material are each bonded to a linear polymer chain via two functional groups. In particular, the linear polymer chains are stretched. Stretching here and in the following means that a material is deformed in order to produce anisotropic alignment. The stretching causes the linear polymer chains to be aligned anisotropically, in particular parallel to one another. As a result of the bonding of the emitter material to the polymer, an anisotropic alignment of the molecules of the emitter material thus also takes place. The alignment of the emitter material has the result that the transition dipole moments of the radiation-generating transition of the molecules of the emitter material have an anisotropic alignment overall in the light-emitting layer. In particular, the orientation factor K e is less than 1 / 3. The transition dipole moments of the radiation-generating transition of the radiation-generating transition of the molecules of the emitter material are preferably arranged in total perpendicular to a layer normal of the light-emitting layer with a maximum deviation of + / -45° from this perpendicular orientation.According to one embodiment, the light-emitting layer is produced from a functionalized polymer having a structural unit of one of the following formulae: Here and in the following, the symbol "*" stands for a binding site of the repeating structural unit which is connected to a next structural unit. In addition, at the end of the polymer chain, end groups may terminate the polymer, comprising, for example, epoxy, hydroxy, carbonyl, or chloride groups. However, other common end groups are also conceivable. In particular, the functionalized polymer having one of these structural units is selected for the production of the light-emitting layer if one or more molecules of the emitter material are each bonded to a linear polymer chain via two functional groups.In one embodiment, the light emitting layer comprises a structural unit formed from the polymer and the emitter material of the following general formula: FG represents a functional group via which the emitter material E is bonded to the polymer. In this embodiment, at least one molecule of the emitter material is bonded to a linear polymer chain via two functional groups. In particular, the linear polymer chain is stretched. The functional group may comprise an ester, ether, amide, hydroxy and / or ether group. At the end of the polymer chain, end groups may terminate the polymer, including, for example, epoxy, hydroxy, carbonyl or chloride groups. However, other common end groups are also conceivable.For example, the light-emitting layer comprises a structural unit formed from the polymer and the emitter material of one of the following formulae: Here, at least one molecule of the emitter material is bonded to the linear polymer chains via two ester groups. This material can be prepared from a perylene functionalized twice with an acid chloride group and a polyethylene having hydroxyl side groups.According to one embodiment, one or more molecules of the emitter material are bonded via two functional groups to a linear polymer chain and to a further linear polymer chain. The linear polymer chains are then connected to one another via the molecules of the emitter material. In other words, the linear polymer chains are then crosslinked via the molecules of the emitter material. Due to the anisotropic alignment of the linear polymer chains before the bonding of the emitter material, for example by stretching, the emitter material is also aligned after the bonding thereof to the linear polymer chains. This has the result that the transition dipole moments of the radiation-generating transition of the molecules of the emitter material have an anisotropic alignment overall in the light-emitting layer. In particular, the orientation factor K e is less than 1 / 3. Preferably, the transition dipole moments of the radiation-generating transition of the radiation-generating transition of the molecules of the emitter material are arranged in total perpendicular to a layer normal of the light-emitting layer with a maximum deviation of + / -45° from this perpendicular orientation. The associated reduced total reflection and reduced excitation of waveguiding effects make it possible to provide an organic light-emitting component which has a high light decoupling and thus high efficiency.According to one embodiment, the light-emitting layer is produced from a functionalized polymer having a structural unit of one of the following formulae: In particular, the functionalized polymer having one of these structural units is selected for the production of the light-emitting layer if the molecules of the emitter material are each bonded via a functional group to one and another linear polymer chain.In one embodiment, the light emitting layer comprises a structural unit formed from the polymer and the emitter material of the following general formula: FG represents a functional group via which the emitter material E is bonded to the polymer. In this embodiment, the molecules of the emitter material are bonded via two functional groups to a linear polymer chain and a further linear polymer chain. The linear polymer chains are crosslinked via the molecules of the emitter material. "------" indicates the bond to a further molecule of the emitter material, which is then bonded via a further functional group to a further linear polymer chain. The functional group may comprise an ester, ether, amide, hydroxy and / or ether group. At the end of the polymer chain, end groups may terminate the polymer, comprising, for example, epoxy, hydroxy, carbonyl or chloride groups. However, other common end groups are also conceivable.For example, the light-emitting layer comprises a structural unit formed from the polymer and the emitter material of the following formula: Here, the molecules of the emitter material are bonded via two ester groups to one linear polymer chain and another linear polymer chain. The linear polymer chains are crosslinked via the molecules of the emitter material. "------" indicates the bond to a further molecule of the emitter material, i.e. perylene, which is then bonded to a further linear polymer chain via a further ester group. At the end of the polymer chain, end groups may terminate the polymer, including, for example, epoxy, hydroxy, carbonyl or chloride groups. However, other common end groups are also conceivable.This material can be prepared from a perylene functionalized twice with an acid chloride group and a polyethylene having hydroxyl side groups.Conventional organic emitter materials can be used as materials for the emitter material. As functionalized emitter material, it is possible in particular to use customary organic emitter materials which are functionalized or substituted with at least one functional group which comprises an amine group, an alcoholate or an acid chloride group. The molecules of the emitter material are bound to the polymer via the at least one functional group.In one embodiment, the emitter material is a fluorescent or phosphorescent material. These materials are known to those skilled in the art. In particular, the functionalized emitter material is a fluorescent or phosphorescent material substituted with at least one functional group comprising an amine group, an alcoholate or an acid chloride group. The molecules of the emitter material are bound to the polymer via the at least one functional group. For example, iridium complexes substituted with at least one functional group, such as green-phosphorescent Ir(ppy) 3( tris(2-phenylpyridine)iridium III) and / or red-phosphorescent Ru(dtb-bpy) 3*2( PF 6) ( tris[4,4'-di-tert-butyl-(2,2')-bipyridine]ruthenium (III) complex), and blue-fluorescent DPAVBi(4,4-bis[4-(di-p-tolylamino)styryl]biphenyl), may be used, Green fluorescent TTPA (9,10-bis[N,N-di-(p-tolyl)-amino]anthracene) and / or red fluorescent DCM2(4-dicyanomethylene)-2-methyl-6-julolideyl-9-enyl-4H-pyran) can be used as emitter material.As fluorescent emitter material, it is also possible, for example, to use 1,4-bis[2-(3-N-ethylcarbazoryl)vinyl]benzene or perylene. The functionalized emitter material is substituted in this embodiment with at least one functional group. For example, the fluorescent functionalized emitter material has one of the following structures: The compounds can be prepared, for example, from appropriately substituted naphthalenes, for example by reaction with aluminum chloride.Phosphorescent materials which can be used are, for example, metal-organic compounds, such as iridium complexes, for example bis(3,5-difluoro-2-(2-pyridyl)phenyl(2-carboxypyridyl)iridium(III). The functionalized emitter material is in this embodiment the corresponding compound substituted with at least one functional group comprising an amine group, an alcoholate or an acid chloride group. The molecules of the emitter material are bound to the polymer via the at least one functional group.The emitter materials used can also be TADF (thermally activated delayed fluorescence) emitters. The functionalized emitter material is in this embodiment the corresponding compound substituted with at least one functional group comprising an amine group, an alcoholate or an acid chloride group. The molecules of the emitter material are bound to the polymer via the at least one functional group. The TADF emitters can be organic or organometallic compounds. For example, 9,9'-(4,4'-sulfonylbis(4,1-phenylene))bis(3,6-di-tert-butyl-9H-carbazoles, 9,10-bis[N,N -di-(p-tolyl)amino]anthracene or 2,8-di-tert-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyltetracene substituted by at least one functional group comprising an amine group, an alcoholate or an acid chloride group can be used as functionalized emitter material.The emitter material is a square planar transition metal complex, in particular Pt(II) or Pd(II) is selected as the transition metal central atom. In this embodiment, the functionalized emitter material is the square planar transition metal complex substituted with at least one functional group comprising an amine group, an alcoholate or an acid chloride group. For example, it is tetracyanoplatinate wherein a CN group is substituted by a functional group.The emitter material is a square-planar transition metal complex, wherein the square-planar transition metal complex is bonded via a functional group to the polymer, in particular to the linear polymer chains. As a result of the interaction of the dz 2- orbitals of the molecules of the square-planar transition metal complex, the molecules of the transition metal complex organize themselves in the light-emitting layer and form stacks in particular. This alignment of the molecules of the emitter material, i.e. of the transition metal complex, also aligns the polymer, in particular the linear polymer chains. This self-organization of the emitter material results in the transition dipole moments of the radiation-generating transition of the molecules of the emitter material having, in total, an anisotropic alignment within the light-emitting layer, and <cos 2 θ> is less than 1 / 3, where θ is the angle between the respective transition dipole moment of the radiation-generating transition of the molecules of the emitter material and a layer normal of the light-emitting layer.According to one embodiment, the light-emitting layer comprises different emitter materials. For example, the light-emitting layer may comprise emitter materials which generate radiation having a different peak wavelength. For example, the light-emitting layer may comprise an emitter material having a peak wavelength in the blue region of the electromagnetic spectrum and an emitter material having a peak wavelength in the red region of the electromagnetic spectrum.By aligning or orienting the emitter material in a light-emitting layer, the light yield, i.e. the radiation decoupled from the outside to the environment, is increased and the efficiency of the component is thus increased. In addition, the degree of polarization of the generated radiation is increased. At the same time, this light-emitting layer has high stability due to the uniform alignment of the emitter material and the polymer.According to one embodiment, the light-emitting layer consists of the emitter material and the polymer.A method for producing an organic light-emitting component is furthermore specified. In particular, the method produces the organic light-emitting component according to the above-mentioned embodiments. In this case, the definitions and explanations described hitherto for the organic light-emitting component also apply to the method for producing the organic light-emitting component and vice versa.According to at least one embodiment, the method for producing an organic light-emitting component has the following method steps: A) providing an electrode, B) producing a light-emitting layer on the electrode provided in method step A). The light-emitting layer comprises a polymer and an emitter material, wherein the emitter material is configured to generate electromagnetic radiation during operation of the component. The emitter material is bonded to the polymer in the light-emitting layer. The transition dipole moments of the radiation-generating transition of the molecules of the emitter material have, in total, anisotropic alignment within the first light-emitting layer, and <cos 2 θ> is less than 1 / 3, where θ is the angle between the respective transition dipole moment of the radiation-generating transition of the molecules of the emitter material and a layer normal of the first light-emitting layer, C) applying a further electrode to the light-emitting layer.The fact that a layer is arranged, produced or applied "on" or "over" another layer can mean here and below that the one layer is arranged, produced or applied directly on the other layer in direct mechanical and / or electrical contact. Furthermore, it can also mean that one layer is arranged, produced or applied indirectly on or above the other layer. In this case, further layers can then be arranged between one and the other layer.In one embodiment, method step B) comprises the following method steps:B1) Providing a functionalized polymer comprising linear polymer chains substituted with pendant groups. The pendant groups include epoxy, hydroxy, carbonyl, carboxyl, triflate, tosylate, iodide, bromide or chloride groups, preferably epoxy, hydroxy, carbonyl or chloride groups,B2) providing a functionalized emitter material functionalized with at least one functional group comprising an amine group, an alcoholate or an acid chloride group,B3) Reaction of the side groups of the linear polymer chains of the functionalized polymer with the functional groups of the functionalized emitter material, whereby the emitter material is covalently bonded to the polymer or the linear polymer chains. It is possible here that not all side groups of the functionalized polymer are subject to such a reaction and thus remain in the polymer of the light-emitting layer,B4) Alignment of linear polymer chains.Process step B3) can be carried out before or after process step B4).In one embodiment, the linear polymer chains are aligned anisotropically by stretching in process step B4).In one embodiment, process step B4) takes place after process step B3). According to this embodiment, in the reaction in process step B3), one or more molecules of the emitter material are each bonded to a linear polymer chain via two functional groups. In process step B4), the linear polymer chains formed in process step B3), to which one or more molecules of the emitter material are each bonded via two functional groups, are aligned, in particular stretched. In particular, in process step B1) according to this embodiment, a functionalized polymer is provided which has a structural unit of one of the following formulae: The stretching causes the linear polymer chains to be aligned anisotropically. As a result of the previous connection of the emitter material to the polymer, an anisotropic alignment of the molecules of the emitter material thus also takes place. The alignment of the emitter material results in the transition dipole moments of the radiation-generating transition of the molecules of the emitter material having, in total, an anisotropic alignment within the light-emitting layer, and <cos 2 θ> is less than 1 / 3, where θ is the angle between the respective transition dipole moment of the radiation-generating transition of the molecules of the emitter material and a layer normal of the light-emitting layer.In one embodiment, process step B3) takes place after process step B4). According to this embodiment, in process step B4), the functionalized linear polymer chains provided in process step B1) are aligned, in particular stretched. In the reaction in process step B3), the molecules of the emitter material are each bonded via two functional groups to a linear polymer chain and a further linear polymer chain. In particular, in process step B1) according to this embodiment, a functionalized polymer is provided which has a structural unit of one of the following formulae: Due to the anisotropic alignment of the linear polymer chains before the bonding of the emitter material, for example by stretching, the emitter material is also aligned after the bonding thereof to the linear polymer chains. This leads to the transition dipole moments of the radiation-generating transition of the molecules of the emitter material having, in sum, an anisotropic orientation within the light-emitting layer, and <cos 2 θ> of less than 1 / 3, where θ is the angle between the respective transition dipole moment of the radiation-generating transition of the molecules of the emitter material and a layer normal of the light-emitting layer.In one embodiment, in process step B2), a square planar transition metal complex is selected with Pt(II) or Pd(II) as functionalized emitter material substituted with a functional group comprising an amine group, an alcoholate or an acid chloride group. According to this embodiment, process step B4) takes place after process step B3). In the reaction in process step B3), the molecules of the emitter material are each bonded to the linear polymer chains via a functional group. In process step B4), the linear polymer chains formed in process step B3) are aligned. The alignment is effected by a self-organization of the molecules of the transition metal complex. This alignment of the molecules of the emitter material, i.e. of the transition metal complex, also aligns the linear polymer chains to which the emitter material is bonded. Self-assembly is effected by the interaction of the dz 2- orbitals of the molecules of the square-planar transition metal complex. This self-organization of the emitter material results in the transition dipole moments of the radiation-generating transition of the molecules of the emitter material having, in total, an anisotropic alignment within the light-emitting layer, and <cos 2 θ> is less than 1 / 3, where θ is the angle between the respective transition dipole moment of the radiation-generating transition of the molecules of the emitter material and a layer normal of the light-emitting layer.In one embodiment, method step B) comprises the following method step: B5) applying the material formed in method step B4) or B3) to the electrode provided in method step A).According to at least one embodiment, the light-emitting layer is produced from the liquid phase in process step B). In process step B5), spin coating, screen printing, inkjet, gravure printing or flexographic printing can be used as the process. During production, an aligned or oriented light-emitting layer can be produced without additional method steps being necessary. This leads to time and cost savings.According to at least one embodiment, the alignment in method step B 4) is carried out at temperatures between 20° C. and 120° C. Such temperatures are customary in the production of organic electronics. At such high temperatures, alignment of molecules of emitter materials with external fields cannot be achieved. Therefore, according to the invention, recourse is made here to the alignment of the emitter material as a result of the alignment of the linear polymer chains or to the self-organization of the molecules of the emitter material, in particular of square-planar transition metal complexes.Furthermore, a higher efficiency is ensured with a constantly high component stability. Furthermore, the morphology can be influenced in order to improve the performance of the component. The influence on the morphology can be effected by the alignment of the emitter material and the polymer chains.Furthermore, a component may be provided which may produce potentially increased stability by uniform alignment of the molecules of the emitter material in the light-emitting layer.Further advantages, advantageous embodiments and refinements emerge from the exemplary embodiments described below in conjunction with the figures. FIG. 1 shows various possible arrangements of molecules in space, FIG. 2 shows a schematic side view of an exemplary embodiment of an organic light-emitting component, FIGS. 3, 4, 5 schematically show the production of aligned linear polymer chains and emitter materials for light-emitting layers, FIGS. 6, 7 and 8 show schematic representations of a section of an organic light-emitting component according to various embodiments.In the exemplary embodiments and figures, identical, identical or identically acting elements can each be provided with the same reference numerals. The elements shown and their size relationships to one another are not to be regarded as being to scale, rather individual elements, such as layers, components, components and regions, for example, may be shown with exaggerated size for better clarity and / or for better understanding.FIG. 1 shows various possible arrangements of molecules in space. In the upper illustration, the molecules are isotropically distributed, i.e. have no preferred direction. In the middle and bottom figures, the molecules are aligned along the z-axis. In addition, the molecules in the bottom image are oriented along the z-axis.FIG. 2 shows a schematic side view of an organic light-emitting component 100 according to an embodiment, which comprises a substrate 1, for example made of glass. Above the substrate 1, an organic layer stack S is arranged between an anode 2 and a cathode 3. The organic layer stack S has a hole transporting layer 5 arranged over the anode 2 and an electron transporting layer 6 arranged over the light emitting layer 4.The anode 2 can be formed from indium tin oxide and the cathode 3 from aluminum or silver. For example, hole transporting layer 5 may comprise NPB (N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine) and electron transporting layer 6 may comprise 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole.The light emitting layer 4 comprises a polymer and an emitter material. The polymer comprises linear polymer chains to which the emitter material is bonded via at least one functional group. The linear polymer chains and the molecules of the emitter material are aligned anisotropically in the light-emitting layer. As a result, the transition dipole moments of the radiation-generating transition of the molecules of the emitter material are aligned anisotropically in total within the light-emitting layer, and <cos 2 θ> is less than 1 / 3, where θ is the angle between the respective transition dipole moment of the radiation-generating transition of the molecules of the emitter material and a layer normal of the light-emitting layer.Furthermore, an encapsulation arrangement, preferably in the form of a thin-film encapsulation, can be applied (not shown) over the electrodes 2, 3 and the organic functional layer stack S in the light-emitting components of FIG. 2 in order to protect the organic light-emitting component 100 and in particular the layers of the organic functional layer stack S and the electrodes 2, 3 from damaging materials from the environment, such as moisture and / or oxygen and / or other corrosive substances, such as hydrogen sulfide.In the component 100 shown in FIG. 2, the position of the anode 2 and the cathode 3, and of the hole-transporting layer 5 and of the electron-transporting layer 6 can be interchanged.Figure 3 illustrates a reaction of a functionalized polymer comprising linear polymer chains with a functionalized emitter material E disubstituted with an acid chloride group. The linear polymer chains of the polyethylene having hydroxyl side groups are aligned anisotropically, in particular parallel to one another, for example by stretching, which is indicated by the parallel arrangement of the two polymer chains. Under alkaline conditions, the hydroxy pendant groups of the functionalized polymer partially react with the acid chloride groups of the functionalized emitter material to form an ester group. The emitter material is connected to the polymer via an ester group each having a linear polymer chain and a further polymer chain. In other words, the linear polymer chains are crosslinked via the molecules of the emitter material. The alignment of the linear polymer chains also aligns the emitter material, so that the transition dipole moments of the radiation-generating transition of the molecules of the emitter material overall have anisotropic alignment within the light-emitting layer, and <cos 2 θ> is less than 1 / 3, where θ is the angle between the respective transition dipole moment of the radiation-generating transition of the molecules of the emitter material and a layer normal of the light-emitting layerIt is possible that instead of the OH groups in the product, further molecules of the emitter material are bonded to further polymer chains via ester groups.The reaction product shown may be introduced into the light-emitting layer 4 of the component 100 from FIG. 2.FIG. 4 shows that molecules of an emitter material E are bonded via in each case two functional groups FG to in each case one linear polymer chain of a polymer. First, the linear polymer chains are present anisotropically. After stretching, the linear polymer chains are aligned, as represented by their parallel arrangement. The alignment of the linear polymer chains also aligns the emitter material, so that the transition dipole moments of the radiation-generating transition of the molecules of the emitter material overall have anisotropic alignment within the light-emitting layer, and <cos 2 θ> is less than 1 / 3, where θ is the angle between the respective transition dipole moment of the radiation-generating transition of the molecules of the emitter material and a layer normal of the light-emitting layerThe reaction product shown may be introduced into the light-emitting layer 4 of the component 100 from FIG. 2.Figure 5 shows that molecules of an emitter material E are each bonded via a functional group FG to a linear polymer chain of a polymer. The emitter material is a square-planar transition metal complex having Pt(II) as the transition metal central atom and three ligands R and one ligand R'. Via R' and a functional group FG, the emitter material is bonded to the linear polymer chains. First, the linear polymer chains are present anisotropically. By interaction of the dz 2 orbitals of the molecules of the transition metal complex, these organize themselves and align themselves. This also aligns the linear polymer chains, which is represented by their parallel arrangement. As a result of this alignment, the transition dipole moments of the radiation-generating transition of the molecules of the emitter material have, in total, an anisotropic alignment within the light-emitting layer, and <cos 2 θ> is less than 1 / 3, where θ is the angle between the respective transition dipole moment of the radiation-generating transition of the molecules of the emitter material and a layer normal of the light-emitting layer.FIGS. 6, 7 and 8 each show a section of an organic light-emitting component 100 according to one embodiment. The figures each show a light-emitting layer 4 comprising an emitter material and a polymer. The molecules of the emitter material 10 each have a transition dipole moment 11 for the radiation-generating transition, which generates electromagnetic radiation during operation of the component. FIGS. 6 and 7 show that the transition dipole moments 11 are arranged perpendicular to the layer normal N of the light-emitting layer. FIG. 8 shows that the transition dipole moments 11 have a deviation of approximately 10° from the perpendicular arrangement to the layer normal N. By orienting the transition dipole moments of the radiation-generating transition, the radiation generated is emitted anisotropically and thus advantageously impinges at an angle through the further layers such that no or almost no total reflection of the radiation occurs at the boundary surfaces of the layers with one another or with respect to the ambient air and thus more radiation is coupled out to the outside. This increases the efficiency of the component and the degree of polarization of the generated radiation.The cutouts shown in FIGS. 6, 7 and 8 can be introduced into an organic light-emitting component 100, as described, for example, in FIG. 2.The exemplary embodiments described in connection with the figures and the features thereof can also be combined with one another according to further exemplary embodiments, even if such combinations are not explicitly shown in the figures. Furthermore, the exemplary embodiments described in connection with the figures can have additional or alternative features according to the description in the general part.List of reference characters1 Substrate 2 Anode 3 Cathode 4 Light-emitting layer 5 Hole-transporting layer 6 Electron-transporting layer 10 Molecule of the emitter material 11 Transition dipole moment 100 Organic light-emitting component N Layer normal of the light-emitting layer S of organic layer stacks

Claims

Organic light-emitting component (100) comprising an organic layer stack (S) between two electrodes (2, 3), wherein the organic layer stack (S) comprises a light-emitting layer (4) and the light-emitting layer (4) comprises a polymer and an emitter material, wherein - the emitter material is configured to generate electromagnetic radiation during operation of the component, - the transition dipole moments (11) of the radiation-generating transition of the molecules of the emitter material (10) have, in total, an anisotropic orientation within the light-emitting layer and <cos 2 Θ> smaller than 1 / 3, wherein Θ is the angle between the respective transition dipole moment (11) of the radiation-generating transition of the molecules of the emitter material (10) and a layer normal (N) of the light-emitting layer (4), the molecules of the emitter material (10) are bonded to the polymer, the polymer has linear polymer chains and the linear polymer chains are aligned anisotropically, and the emitter material is a square planar transition metal complex and one or more molecules of the transition metal complex are bonded to a linear polymer chain.Organic light-emitting component (100) according to Claim 1, wherein more than 80% of all transition dipole moments (11) of the molecules of the emitter material (10) are arranged perpendicular to the layer normal (N) of the light-emitting layer (4) with a deviation of at most ± 45° from this perpendicular orientation.Organic light-emitting component (100) according to one of the preceding claims, wherein the molecules of the emitter material (10) are bonded to the polymer via at least one functional group and the functional group comprises an ester, amide, hydroxy and / or ether group.Organic light emitting device (100) according to any of the preceding claims, wherein the light emitting layer (4) is made of a functionalized polymer and a functionalized emitter material, wherein the functionalized polymer comprises linear polymer chains substituted with pendant groups comprising epoxy, hydroxy, carbonyl, carboxyl, triflate, tosylate, iodide, bromide or chloride groups and wherein the functionalized emitter material is functionalized with a functional group comprising an amine group, an alcoholate or an acid chloride group.Method for producing an organic light-emitting component (100), having the method steps: A) providing an electrode (2, 3), B) producing a light-emitting layer (4) comprising a polymer and an emitter material on the electrode (2, 3) provided in method step A), wherein - the emitter material is configured to generate electromagnetic radiation during operation of the component, and - the transition dipole moments (11) of the radiation-generating transition of the molecules of the emitter material (10) have, in total, an anisotropic orientation within the light-emitting layer, and <cos 2 θ > smaller than 1 / 3, wherein θ is the angle between the respective transition dipole moment (11) of the radiation-generating transition of the molecules of the emitter material (10) and a layer normal (N) of the light-emitting layer (4), and - the molecules of the emitter material (10) are bonded to the polymer; C) applying a further electrode (2, 3) to the light-emitting layer (4), wherein method step B) comprises the following method steps: B1) providing a functionalized polymer comprising linear polymer chains which are substituted with pendant groups and the pendant groups comprise epoxy, hydroxyl, carbonyl, carboxyl, triflate, tosylate, iodide, bromide or chloride groups; B2) providing a functionalized emitter material which is functionalized with at least one functional group which comprises an amine group, an alcoholate or an acid chloride group; B3) Reaction of the side groups of the linear polymer chains of the functionalized polymer with the functional groups of the functionalized emitter material, thereby bonding the emitter material to the linear polymer chains; B4) aligning the linear polymer chains - wherein the polymer has linear polymer chains and the linear polymer chains are anisotropically aligned, and the emitter material is a square planar transition metal complex and one or more molecules of the transition metal complex are bonded to a linear polymer chain.The method of claim 5, wherein the linear polymer chains are anisotropically oriented by stretching in step B4).Method according to either of Claims 5 and 6, wherein - method step B4) takes place after method step B3), and - in the reaction in method step B3), one or more molecules of the emitter material (10) are each bonded to a linear polymer chain via two functional groups, and wherein - in method step B4), the linear polymer chains formed in method step B3), to which one or more molecules of the emitter material (10) are each bonded via two functional groups, are aligned.The process according to claim 7, wherein in process step B1) a functionalized polymer is provided which has a structural unit of one of the following formulae: Method according to either of Claims 5 and 6, wherein - process step B3) takes place after process step B4) and - in process step B4) the linear polymer chains of the functionalized polymer provided in process step B1) are aligned and - in the reaction in process step B3) the molecules of the emitter material (10) are in each case bonded via two functional groups to a linear polymer chain and a further linear polymer chain.The process according to claim 9, wherein in process step B1) a functionalized polymer is provided which has a structural unit of one of the following formulae: The method according to claim 5, wherein - method step B4) takes place after method step B3) and - in method step B2), a square-planar transition metal complex is selected with Pt (II) or Pd (II) as transition metal central atom as functionalized emitter material and the transition metal complex is substituted with a functional group comprising an amine group, an alcoholate or an acid chloride group, - in the reaction in method step B3), the molecules of the transition metal complex are each bound via a functional group to the linear polymer chains, and - in method step B4), the linear polymer chains formed in method step B3) are aligned.The method of claim 11, wherein the alignment of the linear polymer chains is by a self-organization of the transition metal complex.

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