Organic light-emitting component

Abstract

An organic light-emitting component (100) is specified, which comprises a carrier (1) and an organic layering sequence (2) arranged on the carrier (1). The organic layering sequence (2) comprises at least two organic layers, wherein at least one of the organic layers is designed as an emitting layer (23). The emitting layer (23) emits light (200) of a first wavelength range, which has an intensity maximum at a first wavelength. Further, the organic light-emitting component (100) comprises an anode (3) and a cathode (4) which provide the electrical contacting of the organic layering sequence (2). Further, the organic light-emitting component (100) has at least one nanoparticle layer (20), wherein one nanoparticle layer (20) is an organic layer of the organic layering sequence (2) provided with first nanoparticles (5). The first nanoparticles (5) have a refractive index (nN) that is smaller than at least one refractive index of an organic material of one of the organic layers. Further, at least one nanoparticle layer (20) is not in direct contact with the anode (3). In addition, the first nanoparticles (5) have a diameter that is smaller than one-fourth of the first wavelength at which the light (200) emitted by the emitting layer (23) has an intensity maximum.

Claims

1. A light-emitting component, comprising: a carrier; an organic layer sequence comprising at least two organic layers, the organic layer sequence being arranged on the carrier, wherein at least one of the organic layers is embodied as an emitter layer, which emits light in a first wavelength range having an intensity maximum at a first wavelength; a first electrode and a second electrode, wherein the first electrode is embodied as an anode and the second electrode is embodied as a cathode, wherein the anode and the cathode are provided for electrically contacting the organic layer sequence, and wherein the organic layer sequence is arranged between the anode and the cathode; and at least one nanoparticle layer, wherein a nanoparticle layer is an organic layer of the organic layer sequence that is provided with first nanoparticles, wherein the first nanoparticles have a refractive index (n.sub.N) that is less than at least one refractive index of an organic material of one of the organic layers, wherein at least one nanoparticle layer is not in direct contact with the anode, and wherein the first nanoparticles have a diameter that is less than one quarter of the first wavelength.

2. The component according to claim 1, wherein at least one organic layer that adjoins the anode is free of first nanoparticles, wherein the layer is embodied as a hole injection layer, and wherein the difference between the refractive index of the nanoparticle layer and the refractive index of the anode and/or of the cathode and/or the carrier is ≦0.1.

3. The component according to claim 1, wherein the first nanoparticles have a diameter of less than or equal to 10 nm, and wherein the first nanoparticles comprise SiO.sub.2 and/or MgF.sub.2 as material component.

4. The component according to claim 1, wherein at least one organic layer that adjoins the anode is free of first nanoparticles, and wherein the layer is embodied as a hole injection layer.

5. The component according to claim 1, wherein all the organic layers are embodied as nanoparticle layers.

6. The component according to claim 1, wherein a proportion by volume of the first nanoparticles in the at least one nanoparticle layer is at least 10% and a maximum of 70%.

7. The component according to claim 1, wherein the refractive index of the first nanoparticles (n.sub.N) for visible light is between 1.3 and 1.6.

8. The component according to claim 1, wherein the first nanoparticles comprise a light-converting material, which at least partly absorbs light in a first wavelength range emitted by the emitter layer and converts it into light in a second wavelength range.

9. The component according to claim 1, wherein, in addition to the first nanoparticles, second nanoparticles are introduced into the organic layer sequence, and wherein the second nanoparticles have diameters of ≧150 nm.

10. The component according to claim 1, wherein the at least one emitter layer has a thickness of between 100 nm and 400 nm inclusive, and wherein the organic layer sequence has a total thickness of between 200 nm and 1000 nm inclusive.

11. The component according to claim 1, wherein the layer sequence comprises a plurality of emitter layers provided for emitting electromagnetic radiation, and wherein at least one charge generating layer is situated between at least two of the emitter layers.

12. The component according to claim 1, wherein exclusively the emitter layer or the emitter layers comprise(s) first and/or second nanoparticles.

13. The component according to claim 1, wherein coupling-out structures are introduced between at least one of the two electrodes and the organic layer sequence.

14. The component according to claim 12, wherein the coupling-out structures comprise the second nanoparticles.

15. The component according to claim 1, wherein the anode and/or the cathode comprise(s) a transparent conductive oxide material and/or silver nanowires and/or a metal lattice that is integrated into an organic hole injection layer and/or into an organic electron injection layer.

16. A light-emitting component, comprising: a carrier; an organic layer sequence comprising at least two organic layers, the organic layer sequence being arranged on the carrier, wherein at least one of the organic layers is embodied as an emitter layer, which emits light in a first wavelength range having an intensity maximum at a first wavelength; and a first electrode and a second electrode, wherein the first electrode is embodied as an anode and the second electrode is embodied as a cathode, wherein the anode and the cathode are provided for electrically contacting the organic layer sequence, wherein all the organic layers are embodied as nanoparticle layers, except one organic layer that directly adjoins the anode, wherein a nanoparticle layer is an organic layer of the organic layer sequence that is provided with first nanoparticles, wherein the first nanoparticles have a refractive index (n.sub.N) that is less than at least one refractive index of an organic material of one of the organic layers, wherein the first nanoparticles have a diameter that is less than one quarter of the first wavelength, wherein the first nanoparticles have a diameter of less than or equal to 10 nm, wherein the difference between the refractive index of the nanoparticle layer and the refractive index of the anode and/or of the cathode and/or the carrier is ≦0.1, wherein a proportion by volume of the first nanoparticles in the at least one nanoparticle layer is at least 10% and a maximum of 70%, and wherein the organic layer that adjoins the anode is free of first nanoparticles.

17. A light-emitting component, comprising a carrier; an organic layer sequence comprising at least two organic layers, the organic layer sequence being arranged on the carrier, wherein at least one of the organic layers is embodied as an emitter layer, which emits light in a first wavelength range having an intensity maximum at a first wavelength; a first electrode and a second electrode, wherein the first electrode is embodied as an anode and the second electrode is embodied as a cathode, wherein the anode and the cathode are provided for electrically contacting the organic layer sequence, wherein all the organic layers are embodied as nanoparticle layers, wherein a nanoparticle layer is an organic layer of the organic layer sequence that is provided with first nanoparticles, wherein the first nanoparticles have a refractive index (n.sub.N) that is less than at least one refractive index of an organic material of one of the organic layers, wherein the first nanoparticles have a diameter that is less than one quarter of the first wavelength, wherein the first nanoparticles have a diameter of less than or equal to 10 nm, wherein the difference between the refractive index of the nanoparticle layer and the refractive index of the anode and/or of the cathode and/or the carrier is ≦0.1, and wherein a proportion by volume of the first nanoparticles in the at least one nanoparticle layer is at least 10% and a maximum of 70%.

Description

(1) In the figures:

(2) FIGS. 1 to 5 show schematic illustrations of exemplary embodiments of organic light-emitting components described here.

(3) FIG. 1 depicts a sectional illustration of a first exemplary embodiment of an organic light-emitting component 100. The component 100 comprises a carrier 1, on which an anode 3 is arranged. An organic layer sequence 2 is arranged on that side of the anode 3 which faces away from the carrier 1. Furthermore, a cathode 4 is disposed downstream of the organic layer sequence 2 in a direction away from the carrier.

(4) The carrier 1 preferably comprises a material that is transparent to a light generated by the organic layer sequence 2, for example glass.

(5) The anode 3 preferably comprises a transparent conductive material. By way of example, the anode 3 is produced from indium tin oxide, ITO for short. Alternatively or additionally, the anode 3 can comprise silver nanowires that result in a better conductivity of the anode 3. Moreover, or in addition, the anode 3 can be produced from an organic material and comprise a metal lattice. The anode 3 has a thickness of approximately 100 nm, for example.

(6) The organic layer sequence 2 arranged on the anode 3 comprises three organic layers in the exemplary embodiment given. The layer adjoining the anode 3 is embodied as a hole injection layer 21, HIL for short. The hole injection layer 21 can comprise or consist of a material component composed of PEDOT:PSS, for example. The HOMO, Highest Occupied Molecular Orbital, of the hole injection layer preferably lies energetically between the conduction band level of the anode 3 and the HOMO of the organic layer adjoining the hole injection layer 21. The hole injection layer 21 can thus reduce the energy barrier for hole injection from the anode 3. The hole injection layer 21 has a thickness of approximately 50 nm, for example.

(7) A hole transport layer 22 is arranged in the layer sequence 2 on that side of the hole injection layer 21 which faces away from the carrier 1. The hole transport layer 22 is provided for effectively transferring holes from the anode 3 into further organic layers of the layer sequence 2. The hole transport layer 22 has a thickness of approximately 100 nm, for example.

(8) An emitter layer 23 is disposed downstream on that side of the hole transport layer 22 which faces away from the carrier. The emitter layer 23 can comprise fluorescent or phosphorescent emitter materials, for example. The emitter layer can for example comprise organic polymers, organic oligomers, organic monomers or organic small non-polymeric molecules or contain a combination of these materials. The emitter materials introduced into the emitter layer 23 can be provided for generating light 200 having different wavelengths, for example for generating blue light or green light or red light. The emitter layer 23 can for example also comprise a mixture of different emitters, such that the emitter layer 23 emits mixed light 200, for example white light. Furthermore, the emitter layer 23 can comprise a plurality of individual emitter layers which for example each emit light of different colors. By way of example, a first emitter layer can emit red light, a second emitter layer can emit green light and a third emitter layer can emit blue light. The emitter layer 23 has a thickness of approximately 200 nm, for example.

(9) In the exemplary embodiment in FIG. 1, the emitter layer 23 is embodied as a nanoparticle layer 20 comprising first nanoparticles 5. In this case, the first nanoparticles 5 are preferably chosen such that their diameter is less than one quarter of a wavelength λmax at which the light 200 emitted by the emitter layer 23 has an intensity maximum. By way of example, the diameter of the first nanoparticles 5 is less than one tenth of the wavelength λmax.

(10) The first nanoparticles 5 preferably have a refractive index n.sub.N that is less than the refractive index of the organic material of the organic layer into which the first nanoparticles 5 are introduced, which is the emitter layer 23 in FIG. 1. By way of example, the refractive index of the first nanoparticles is 1.5, and the refractive index of the organic material of the emitter layer is 1.8, for example.

(11) A cathode 4 is arranged on that side of the layer stack 2 which faces away from the carrier 2. The cathode 4, like the anode 3, can be produced from a transparent conductive material or comprise such a material. In the exemplary embodiment in FIG. 1, the cathode is produced from a reflective material, for example from aluminum or from silver. The cathode 4 has a thickness of 50 nm, for example.

(12) In the exemplary embodiment in FIG. 1, the light 200 emitted by the emitter layer 23 is coupled out from the component 100 via the anode 3 and the carrier 1.

(13) Furthermore, in FIG. 1, the organic layers indicated are preferably arranged one directly above another. Alternatively or additionally, further organic layers, such as electron injection layers or coupling-out layers, can be integrated into the organic layer sequence. These additional layers can be fitted for example as intermediate layers between the organic layers shown in FIG. 1. The same correspondingly applies to all the other exemplary embodiments.

(14) The component 100 indicated in FIG. 1 can be produced by the following process steps, for example:

(15) In a first step, the anode 3 is applied to a carrier 1. In a second step, the organic layers of the layer sequence 2 are applied successively above the anode 3 by means of solvent-based processes, for example by means of a spin-coating method. During the application of the emitter layer 23, the organic materials of the emitter layer 23 and the first nanoparticles 5 can be dissolved in a common solvent and thus mixed. In this case, the first nanoparticles 5 can be provided with a surface functionalization, for example, in order to ensure the solubility thereof in the chosen solvent. In a third process step, the metal cathode 4 is applied to the organic layer sequence 2 by means of a vapor deposition process, for example.

(16) Alternatively or additionally, the organic layers and the first nanoparticles 5 can also be applied in a common evaporation process. By way of example, an organic material and the material forming the first nanoparticles 5 can be co-evaporated by thermal vapor deposition, wherein the material forming the first nanoparticles 5 agglomerates to form first nanoparticles 5 in the vapor-deposited layer.

(17) FIG. 2 illustrates a further exemplary embodiment of the light-emitting organic component 100. In this case, the component 100 comprises the same layer sequence as, or a similar layer sequence to, the component 100 illustrated in FIG. 1. In contrast to the exemplary embodiment illustrated in FIG. 1, the anode 3 is not transparent to the light 200 emitted by the emitter layer 23. The anode 3 is produced for example from a metal such as silver or aluminum and can be reflective to the light 200 emitted by the emitter layer 23. Conversely, the cathode 4 comprises or consists of a transparent conductive material.

(18) Furthermore, in FIG. 2 all the organic layers of the organic layer sequence 2 comprise first nanoparticles 5. Preferably, in this case the refractive index of the first nanoparticles 5 in each organic layer is less than the refractive index of the organic materials of the respective organic layer.

(19) In the case of the exemplary embodiment in accordance with FIG. 3, the component 100 comprises further organic layers. By way of example, an electron transport layer 24 and an electron injection layer 25 are arranged between an emitter layer 23 and the cathode 4. In this case, the electron injection layer 25 directly adjoins the cathode 4 and provides for effective coupling of electrons from the cathode 4 into the organic layer sequence 2; for example, the electron injection layer 25 reduces the energy barrier for the injection of electrons. The electron injection layer 25 has a thickness of 50 nm, for example.

(20) In FIG. 3, the electron transport layer 24 is arranged between the electron injection layer 25 and the emitter layer 23. The electron transport layer 24 provides for effectively transferring the electrons injected from the cathode 4 into the emitter layer 23. The electron transport layer 24 has a thickness of 100 nm, for example.

(21) In FIG. 3, as in FIG. 1, the light 200 is emitted from the component 100 via the anode 3 and the carrier 1. In this case, the anode 3 is transparent to the light 200 emitted by the emitter layer 23, and the cathode 4 can be reflective to the light 200 emitted by the emitter layer 23; by way of example, it can consist of silver, aluminum or gold or comprise silver, aluminum or gold.

(22) The component 100 in FIG. 3 comprises two emitter layers 23. Alternatively, however, a plurality of emitter layers, for example three or four emitter layers, can also be integrated into the layer sequence 2 (not shown in FIG. 3). The two emitter layers 23 are connected to one another via a charge generating layer 26, CGL for short, for example.

(23) In FIG. 3, exclusively the emitter layers 23 comprise first nanoparticles 5. In addition to the first nanoparticles 5, the emitter layers 23 comprise second nanoparticles 51. In this case, the second nanoparticles 51 can have a greater diameter than the first nanoparticles 5. By way of example, the diameter of the second nanoparticles 51 is ≧100 nm, such that the second nanoparticles 51 preferably act as scattering centers for the light 200 emitted by the emitter layers 23 and thus reduce the proportion of light subjected to total internal reflection. The diameter of the first and/or second nanoparticles is preferably at most 50% of the diameter of the respective organic layers which comprise the first and/or second nanoparticles.

(24) The second nanoparticles 51 can be arranged in the same organic layer or in the same organic layers as the first nanoparticles 5, as shown in FIG. 3. Alternatively, however, the second nanoparticles 51 can also be arranged in other or additional organic layers.

(25) In FIG. 3, coupling-out structures 6 are arranged on that side of the carrier 1 which faces away from the layer sequence 2. The coupling-out structures 6 can be applied to the carrier 1 in the form of a coupling-out film, for example. Alternatively or additionally, structurings of the carrier 1 can serve as coupling-out structures 6. Preferably, by means of the first nanoparticles 5 and possibly by means of the second nanoparticles 51, the refractive index of the organic layer sequence 2 is reduced to an extent such that the refractive index of the organic layer sequence 2 is less than or equal to the refractive index of the carrier 1. In this case, light can be coupled out from the organic layer sequence 2 into the carrier 1 without losses. The coupling-out structures 6 on the carrier 1 then serve only for coupling out the light from the carrier 1 effectively into the surroundings, for example into the air.

(26) Furthermore, the coupling-out structures 6 can also be arranged in the component 100. By way of example, as shown in FIG. 3, the coupling-out structures 6 can additionally or alternatively be arranged between the cathode 4 and the organic layer sequence 2. The efficiency of coupling out light from the organic layer sequence 2 can further be increased by means of such coupling-out structures 6.

(27) In particular, the coupling-out structures 6 can comprise the second nanoparticles 51 or consist of the latter (not shown in FIG. 3). In this case, the nanoparticles 51 act for example as scattering centers for the light 200 emitted by the organic layer sequence 2.

(28) FIG. 4 shows a further exemplary embodiment of the organic light-emitting component 100, wherein the light generated in the organic layer sequence 2 is emitted from the component 100 via the anode 3 and the cathode 4. In this case, the anode 3, the cathode 4 and the carrier 1 are at least partly transparent to the light emitted by the emitter layer 23. Furthermore, the component 100 in the exemplary embodiment indicated here comprises three organic layers, of which one organic layer directly adjoining the anode 3, for example the hole injection layer 21, is free of first nanoparticles 5 and second nanoparticles 51. Advantageously, the contact area between the anode 3 and the hole injection layer 21 is thus not disturbed or reduced by first nanoparticles 5 and/or second nanoparticles 51. This can in turn have an advantageous effect on the efficiency for the injection of holes into the organic layer sequence 2 and thus have an advantageous effect for the efficiency of the entire organic component 100.

(29) The exemplary embodiment in accordance with FIG. 5 shows the same component as in FIG. 4. In addition, the first nanoparticles 5 illustrated in FIG. 5 optionally comprise a conversion material suitable for at least partly converting the light 200 in a first wavelength range emitted by the emitter layer 23 into light 300 in a second wavelength range. The first nanoparticles 5 can thus serve for an improved or facilitated setting of the color locus of the light emitted by the component 100.

(30) Additionally or alternatively, the nanoparticles 5 can comprise a dye that absorbs part of the light 200 in the first wavelength range and thus generates light 300 in a second wavelength range. Furthermore, second nanoparticles 51 comprising light-converting or light-absorbing material can also be introduced into the organic layer sequence 2.

(31) The invention described here is not restricted by the description on the basis of the exemplary embodiments. Rather, the invention encompasses any novel feature and also any combination of features, which in particular includes any combination of features in the patent claims, even if this feature or this combination itself is not explicitly specified in the patent claims or exemplary embodiments.

(32) This patent application claims the priority of German patent application 10 2013 113 486.6, the disclosure content of which is hereby incorporated by reference.