OLED and method for producing an OLED

Abstract

An OLED and a method for producing an OLED are disclosed. In an embodiment, the OLED includes a substrate and an organic layer stack with at least one active light-generating layer, which is suitable for generating electromagnetic radiation, wherein the organic layer stack is arranged between a first electrode and a second electrode. The OLED further includes a buffer layer arranged between the substrate and the first electrode, wherein the buffer layer includes an organic material, wherein a polymeric planarization layer is in direct contact with the substrate, wherein the buffer layer is in direct contact with the polymeric planarization layer, and wherein the first electrode is in direct contact with the buffer layer.

Claims

1-18. (canceled)

19. An OLED comprising: a substrate; an organic layer stack with at least one active light-generating layer, which is suitable for generating electromagnetic radiation, wherein the organic layer stack is arranged between a first electrode and a second electrode; and a buffer layer arranged between the substrate and the first electrode, wherein the buffer layer comprises an organic material, wherein a polymeric planarization layer is in direct contact with the substrate, wherein the buffer layer is in direct contact with the polymeric planarization layer, and wherein the first electrode is in direct contact with the buffer layer.

20. The OLED according to claim 1, wherein the buffer layer comprises an organic semiconductor material.

21. The OLED according to claim 1, wherein the buffer layer is formed from an organic material, which is also comprised by the organic layer stack.

22. The OLED according to claim 3, wherein the organic layer stack and the buffer layer comprise small molecules.

23. The OLED according to claim 1, wherein the buffer layer comprises the organic material that is depositable by vapor-deposition.

24. The OLED according to claim 1, wherein the buffer layer comprises the organic material that is applicable by wet deposition.

25. The OLED according to claim 1, wherein the buffer layer comprises a material that comprises metal complexes.

26. The OLED according to claim 1, wherein a lateral extent of the organic layer stack and a lateral extent of the buffer layer are equal.

27. The OLED according to claim 1, wherein the substrate is a flexible metal substrate or a flexible plastic film.

28. The OLED according to claim 1, wherein a material of the organic layer stack extends along a side surface of the first electrode all the way to the substrate and electrically insulates the first electrode from the second electrode.

29. The OLED according to claim 1, wherein the OLED is configured to emit radiation, which is generated during operation of the OLED, through the substrate, and wherein the buffer layer has a refractive index of at least 1.6.

30. An OLED comprising: a substrate; an organic layer stack with at least one active light-generating layer, which is suitable for generating electromagnetic radiation, wherein the organic layer stack is arranged between a first electrode and a second electrode; and a buffer layer arranged between the substrate and the first electrode, wherein the buffer layer comprises an organic material, wherein the buffer layer is located directly adjacent to the first electrode, and wherein a layer of the organic layer stack directly adjacent to the first electrode and the buffer layer comprise the same material.

31. A method for manufacturing an OLED, the method comprising: providing a substrate; depositing a buffer layer; and vapor-depositing an organic layer stack, which is arranged between a first electrode and a second electrode, wherein the buffer layer is formed from an organic material, wherein a polymeric planarization layer is directly applied to the substrate, wherein the buffer layer is directly applied to the polymeric planarization layer, and wherein the first electrode is directly applied to the buffer layer.

32. The method according to claim 13, wherein depositing the buffer layer comprises vapor-depositing the buffer layer.

33. The method according to claim 14, wherein the buffer layer and the organic layer stack are vapor-deposited through the same mask.

34. The method according to claim 13, wherein the buffer layer comprises small molecules.

35. The method according to claim 13, wherein the buffer layer is deposited by wet deposition.

36. A method for manufacturing an OLED, the comprising: providing a substrate; depositing a buffer layer; and vapor-depositing an organic layer stack, which is arranged between a first electrode and a second electrode, wherein the buffer layer is formed from an organic material, wherein the buffer layer is directly adjacent to the first electrode, and wherein a layer of the organic layer stack that is directly adjacent to the first electrode and the buffer layer are formed from the same material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Further advantageous embodiments and developments of the invention result from the exemplary embodiments described hereinafter in conjunction with the Figures.

[0074] One exemplary embodiment of a method for producing an OLED is described in more detail by means of the schematic sectional views of FIGS. 1 to 6.

[0075] FIG. 7 shows a schematic sectional view of an OLED according to one exemplary embodiment.

[0076] FIG. 8 shows a schematic plan view of the OLED according to the exemplary embodiment of FIG. 7.

[0077] FIG. 9 shows a schematic sectional view of an OLED according to another exemplary embodiment.

[0078] FIG. 10 shows a schematic plan view of the OLED according to the exemplary embodiment of FIG. 9.

[0079] Like, similar or equivalent elements are indicated with like reference numerals throughout the Figures. The Figures and the size ratios of the elements illustrated in the Figures are not to be considered as being made to scale. Individual elements, in particular layer thicknesses, may rather be illustrated in an exaggerated size for a better illustration and/or better understanding.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0080] In the exemplary embodiment according to FIGS. 1 to 6, a flexible metal substrate 1, e.g., of steel, is provided in a first step (FIG. 1).

[0081] In a next step, which is schematically shown in FIG. 2, a polymeric planarization layer 2 is applied to the substrate 1. The planarization layer 2 is formed from a polymer. For example, the polymeric planarization layer 2 is deposited on the substrate 1 with one of the following methods: printing, e.g., screen-printing or intaglio-printing, inkjet printing, spin-coating, rotation coating, slot die coating, dispensing.

[0082] For example, the polymeric planarization layer 2 can be applied to the substrate 1 in a structured manner, wherein each structural element will later be part of a finished OLED. To that end, the polymeric planarization layer 2 is first applied over the entire surface of substrate 1, e.g., by spin coating or rotation coating and then patterned by exposure and development. As an alternative, it is also possible to leave the polymeric planarization layer 2 on the entire surface of the substrate 1.

[0083] In a next step, which is schematically shown in FIG. 3, a buffer layer 3 is deposited on the polymeric planarization layer 2 in direct contact. To that end, a mask 4 is used, which covers places of the substrate 1 that are not to be provided with the buffer layer 3. Here, the buffer layer 3 is preferably formed from small molecules.

[0084] Then, a first electrode 5 is applied to the buffer layer 3 in direct contact (not shown). An organic layer 6 is vapor-deposited on the first electrode 5, again by means of that mask 4 which had already been used in the deposition process of the buffer layer 3, the organic layer stack comprising an active light-generating layer, which is suitable to emit electromagnetic radiation. In the present case, the organic layer stack 6, just like the buffer layer 3, is preferably formed from small molecules. Preferably, the organic layer stack 6 comprises an organic material, which is also comprised by the buffer layer 3 or from which the buffer layer 3 is formed.

[0085] Finally, a second electrode 7 is deposited on the organic layer stack 6 (FIG. 5).

[0086] In a next step, which is schematically shown in FIG. 6, the substrate 1 is severed along separation lines 8, so that a plurality of OLEDS is produced. Basically, it is also conceivable that a single OLED is produced on a substrate. In this case, this step is omitted.

[0087] In FIGS. 1 to 6, the individual layers of the OLED are shown to have the same lateral extent. However, it is to be noted at this point that this is a purely schematic simplification and does not necessarily have to be embodied in the described method. The lateral extents of the individual layers may rather be different, as described with respect to FIGS. 7 to 10 in an exemplary manner.

[0088] The OLED according to the exemplary embodiment of FIG. 7 comprises a substrate 1, on which a polymeric planarization layer 2, which preferably consists of a polymer, is applied in direct contact. The substrate 1 preferably is a flexible metal substrate, e.g., of steel. A buffer layer 3 is applied to the polymeric planarization layer 2. The buffer layer 3 is formed from an organic material. Preferably, the buffer layer 3 is formed from small molecules.

[0089] A first electrode 5, in this case the anode, is applied to the buffer layer 3. The first electrode 5 extends along a side surface of the buffer layer 3 all the way to the polymeric planarization layer 2.

[0090] An organic layer stack 6, which comprises an active light-generating layer, which is suitable to emit visible light, is applied to the first electrode 5 in direct contact. A material of the organic layer stack 6 extends over a side surface of the first electrode 5 all the way to the buffer layer 3, and further over a side surface of the polymeric planarization layer 2 all the way to the substrate 1. The first electrode 5 is thereby electrically insulated from a second electrode 7, which is located on the organic layer stack 6 in direct contact.

[0091] The second electrode 7, which is the cathode in the present case, also extends over the entire side surface of the underlying layer stack all the way to the substrate 1. In this way, in the case of a conductive substrate 1, as in the present steel substrate, an external electric contacting can be advantageously effected via the substrate 1.

[0092] FIG. 8 shows a schematic plan view of the OLED according to the exemplary embodiment of FIG. 7, and in particular a limitation of the lateral extent and the basic shapes of the individual layers of the OLED.

[0093] As shown in FIG. 8, the substrate 1, the polymeric planarization layer 2, the buffer layer 3, the first electrode 5, the organic layer stack 6 and the second electrode 7 have a rectangular basic shape in the present exemplary embodiment.

[0094] In the OLED according to the exemplary embodiment of FIGS. 7 and 8, the polymeric planarization layer 2 covers a central region of the substrate 1 over the entire surface, while a narrow circumferential peripheral region of the substrate 1 is free from the polymeric planarization layer 2.

[0095] The buffer layer 3 and the organic layer stack 6 have the same lateral extent and are arranged one above the other to be congruent. Thus, FIG. 8 shows a common limitation, which completely runs within the limitation of the polymeric planarization layer 2. The buffer layer 3 and the organic layer stack 6 are arranged within the polymeric planarization layer 2.

[0096] In contrast, the first electrode 5 and the second electrode 7 are arranged offset to one another. The first electrode 5 protrudes from the limitation of the second electrode 7 and the planarization layer 2 on two opposite sides, while the second electrode 7 protrudes from the limitation of the first electrode 5 on the other two sides.

[0097] Furthermore, the first electrode 5 and the second electrode 7 are each arranged offset to the organic layer stack 6. The first electrode 5 and the second electrode 7 protrude from the organic layer stack 6 on two different sides. The first electrode 5 and the second electrode 7 can each be externally electrically contacted on the regions that laterally protrude from the organic layer stack 6.

[0098] The OLED according to the exemplary embodiment of FIGS. 9 and 10 comprises a first electrode 5, which ends on a main surface of the polymeric planarization layer 2.

[0099] Just like the schematic plan view of FIG. 10 of the OLED according to FIG. 9, the substrate 1, the polymeric planarization layer 2, the organic layer stack 6 and the buffer layer 3 have a rectangular basic shape. The arrangement of the substrate 1, the polymeric planarization layer 2, the organic layer stack 6 and the buffer layer 3 in relation to one another is also configured as in the exemplary embodiment according to FIGS. 7 and 8, wherein the planarization layer 2 has a smaller lateral extent.

[0100] However, in contrast to the exemplary embodiment of FIGS. 7 and 8, the shape of the first electrode 5 and of the second electrode 7 each have a bulge on in each case one side of the rectangular basic shape. The first electrode 5 and the second electrode 7 are arranged in such a way that the respective bulge protrudes from the organic material of the buffer layer 3 and the layer stack 6, so that each electrode 5, 7 can be externally electrically contacted via the bulge thereof.

[0101] The invention is not limited to these exemplary embodiments by the description by means of the exemplary embodiments. The invention rather comprises each new feature as well as each combination of features, particularly including each combination of features in the patent claims, even though this features or this combination is not per se explicitly indicated in the patent claims or exemplary embodiments.