Inkjet-printable composition, use of the inkjet-printable composition in an organic optoelectronic component and method for producing the optoelectronic component

Abstract

An inkjet printable composition comprising: • 4 wt% to 11 wt% polyimide precursor, • 52% to 96% by weight of a solvent mixture comprising: • at least 8% by weight ethyl lactate, • at least 14% by weight of γ-butyrolactone, and • Dimethylpropyleneurea where all percentages are given relative to the total weight of the inkjetable composition, wherein the composition has a viscosity, measured by means of a standard rheometer at a temperature in a range of 20°C to 30°C, in a range of 2 mPa·s to 25 mPa·s.

Description

[0001] The invention relates to an inkjet-printable composition, a use of the inkjet-printable composition in an organic optoelectronic component and a method for producing the optoelectronic component.

[0002] Optoelectronic components that use organic materials are desirable due to their excellent properties, such as cost-effectiveness and flexibility. Examples of optoelectronic components include organic light-emitting devices, organic phototransistors, organic photovoltaic cells, and organic photodetectors. Organic light-emitting devices, such as OLEDs or displays, comprise at least one substrate, a plurality of electrodes, and a plurality of organic light-emitting layer structures. The luminous surfaces of organic light-emitting devices are typically defined by a resist structure, for example, the formation of metal busbars on the OLED anode, which are also referred to as grids. However, the grid materials can damage the organic layer structures and lead to degradation of the organic layers near the grid materials.It is assumed that chemical components in the lattice material, such as solvents that have not completely evaporated, free radicals, and non-polymerized components, diffuse into the organic layers and damage them. This effect is known as pixel shrinkage, which is a reduction in the active luminous areas of a pixel from the location of the lattice materials toward the pixel center. Pixel shrinkage can progress in either the off or on state, depending on the damage mechanism.

[0003] Polyimide is traditionally used for resist structures such as grids in OLEDs. These resist structures are traditionally applied using screen printing. However, screen printing does not allow for precise layering of the grid materials on the surface of the other material and has the disadvantage of using a metal mask, which can change shape upon heating or cooling.

[0004] The inkjet printing process represents another option for applying resist structures to an OLED. However, there are currently no polyimide inkjet inks that can be used to create polyimide resist structures in such a way that the luminous surface of the OLED is free from pixel shrinkage.

[0005] EP 2 568 019 A1, US 2008 / 0085361 A1, and US 2009 / 0104414 A1 describe an inkjet ink. US 2007 / 0187672 A1 describes a charge transport varnish. US 2014 / 0155546 A1 describes a polyimide precursor, a polyimide, and a coating solution for undercoat films for image formation.

[0006] The object of the invention is to provide an optoelectronic component that is free of pixel shrinkage or exhibits a reduced pixel shrinkage effect. A further object is to provide a polyimide inkjet ink that can be applied homogeneously to a surface of a material by means of an inkjet process and that is designed such that the organic layer structure of the optoelectronic component is free of damage before, during, or after crosslinking of the polyimide inkjet ink. A further object is to provide a method for producing the optoelectronic component that enables more cost-effective, simplified handling and customized printing of the polyimide inkjet ink.

[0007] The inkjet-printable composition according to the invention comprises, with respect to the total inkjet-printable composition, 4 wt.% to 11 wt.% polyimide precursor, 52 wt.% to 96 wt.% of a solvent mixture comprising at least 8 wt.% ethyl lactate, at least 14 wt.% γ-butyrolactone based on the total weight of the inkjetable composition, and dimethylpropyleneurea, wherein the composition has a viscosity, measured by means of a commonly used rheometer (standard rheometer), in a range of approximately 2 mPa.s to approximately 25 mPa.s, for example approximately 2 mPa.s to approximately 20 mPa.s, for example approximately 4 mPa.s to approximately 20 mPa.s, for example approximately 5 mPa.s to approximately 15 mPa.s. The term "approximately" is used herein to mean that the stated values ​​are to be understood as ± 0.5 mPa.s. This includes the variation in viscosity measurement between different commonly used rheometers.

[0008] The term "inkjet-printable composition" is used herein to mean that the composition can be applied contactlessly or without contact to the material to be printed using a printing system, for example, an inkjet printer. Examples of suitable printing processes are continuous inkjet processes or drop-on-demand processes. For this purpose, the inkjet-printable composition has a viscosity suitable for use with an inkjet printer in the range of approximately 2 mPa.s to approximately 25 mPa.s, for example, approximately 2 mPa.s to approximately 20 mPa.s, for example, approximately 4 mPa.s to approximately 20 mPa.s, for example, approximately 5 mPa.s to approximately 15 mPa.s. The viscosity is measured using a standard rheometer.Furthermore, the inkjet-printable composition has a reciprocal Ohnesorge number (1 / Oh), which for use with an inkjet printer is in the range of 1 to 10, for example 2 to 8, for example 4 to 6. The Ohnesorge number (Oh) describes the ratio of the frictional force to the inertial force and surface force.

[0009] This enables precise, structured application of the inkjet printable composition to the material to be printed and a very high printing resolution.

[0010] The term polyimide precursor is used herein to mean that the composition comprises at least one type of molecule with functional groups that can chemically react, so that the molecules are converted into a product with polyimide functional groups. This results in the inkjet-printable composition comprising the polyimide precursor being more easily deformed in a solvent and applied to the material to be printed than the resist pattern material formed from already crosslinked polyimide. This enables better-structured, homogeneous printing of the inkjet-printable composition onto the material to be printed.

[0011] The term solvent mixture is used herein to mean that at room temperature, for example in a range from 20°C to 30°C, for example in a range from 25°C to 30°C, for example 30°C, it is a mixture of liquids that can dissolve, disperse or dilute a substance, liquids or solids without chemical reactions occurring between the dissolved substance and the solvent. The solvent mixture is selected such that the organic layer structure remains free from damage, so that a pixel shrinkage effect can be avoided or reduced. Furthermore, the proportion of solvent mixture in the composition is selected such that the composition has a viscosity, measured by means of a standard rheometer, in the range of approximately 2 mPa.s to approximately 25 mPa.s, for example approximately 2 mPa.s to approximately 20 mPa.s, for example approximately 4 mPa.s to approximately 20 mPa.s.s, for example, approximately 5 mPa.s to approximately 15 mPa.s and / or a reciprocal Ohnesorge number (1 / Oh) which, for use with an inkjet printer, is in the range of 1 to 10, for example, 2 to 8, for example, 4 to 6. This enables a homogeneous polyimide precursor coating, uniform drying, and homogeneous drying of the composition on the material to be printed.

[0012] In one embodiment, the solvent mixture further comprises at least one solvent. For example, one, two, or three solvents can be added to the solvent mixture. The solvent can comprise or be one of the following solvents: diethylene glycol, acetophenone, benzonitrile, dimethyl sulfoxide, cyclohexanone, and anisole. This allows for better adaptation of the solvent mixture to the desired properties of the inkjet-printable composition, such as viscosity, droplet liquid density, surface tension, Reynolds number, Weber number, and compatibility with the organically functional layer structure. This prevents or reduces the pixel shrinkage effect.

[0013] In another embodiment, the solvent mixture, which comprises at least 8 wt.% ethyl lactate and at least 14 wt.% γ-butyrolactone based on the total weight of the inkjetable composition, further comprises dimethylpropylurea and diethylene glycol. Diethylene glycol is a high-boiling solvent that is particularly suitable as a humectant for ink. This makes it possible to avoid rapid drying of the inkjet-printable composition during printing and thus prevent clogging of the inkjet printer nozzles. This also enables a stable structure of the polyimide precursor coating during evaporation of the solvent mixture.

[0014] In one embodiment, the composition further comprises N-methyl-2-pyrrolidone, for example, at most 1 wt.% based on the total weight of the inkjetable composition. N-methyl-2-pyrrolidone is a dipolar aprotic solvent that acts as a catalyst in the polycondensation of the polyimide precursor into polyimide. This enables clean polycondensation of the polyimide precursor into polyimide with few reaction byproducts.

[0015] In another embodiment, the composition further comprises additives in the range of 1.8 wt% to 4 wt% based on the total weight of the inkjet-printable composition. The additives can also contribute to controlling the rheology of the inkjet-printable composition.

[0016] In another embodiment, the composition is an inkjet ink.

[0017] The term "inkjet ink" is used herein to mean that the inkjet-printable composition exhibits properties such as blot-free performance and, under certain temperature and pressure conditions, a good drying speed. The inkjet ink exhibits a homogeneous dry phase. In other words, a drop of inkjet ink on a substrate exhibits uniform drying. Upon evaporation, the inkjet ink is free of areas containing a higher amount of inkjet-printable composition.

[0018] In a further aspect, an inkjet-printable composition is used in an organic optoelectronic component. The organic optoelectronic component comprises a first electrode on or above a substrate, an organic functional layer structure, a second electrode, and a resist structure. The resist structure is formed from the described inkjet-printable composition. In addition, the organic optoelectronic component can comprise at least one electrical busbar that is electrically and physically connected to one of the electrodes.

[0019] The term "resist structure" can also be understood as a resist layer structure, insulation structure, or grid structure. The term "resist structure" is used here to mean that the structure is cross-linked and thus solid and no longer deformable by itself (e.g., without the addition of solvent).

[0020] The resist structure, due to its composition, prevents or reduces a pixel shrinkage effect in the luminous area of ​​the optoelectronic component.

[0021] In one embodiment, the resist structure can comprise polyimide, ethyl lactate, and γ-butyrolactone. These components ensure good stability of the resist structure and are selected such that the optoelectronic component or the organic functional layer structure remains free from damage. This enables good longevity of the optically active region, for example, the light-emitting region, of the organic optoelectronic component, which is free of pixel shrinkage or exhibits little pixel shrinkage.

[0022] In another embodiment, the resist structure physically isolates the first electrode and the second electrode from each other. For example, the electrodes are thereby free from physical contact. If an electrical busbar is present, the resist structure can electrically and physically isolate the busbar from the organic functional layer structure.

[0023] This makes it possible to prevent a current flow and thus a short circuit between two electrically conductive areas, for example between the first electrode and the second electrode or between the busbar and the organic functional layer structure.

[0024] In yet another aspect, a method for producing an optoelectronic component is provided. The method comprises applying an inkjet-printable composition to or over an electrode structure using an inkjet process and crosslinking the inkjet-printable composition to form a polyimide resist structure. The inkjet-printable composition corresponds to a described embodiment of an inkjet-printable composition.

[0025] The term electrode structure is used herein to mean that it can be, for example, an electrode or a busbar.

[0026] The term inkjet process is used herein to mean that the inkjet printable composition is applied to the material to be printed in a contactless or non-contact manner.

[0027] The term crosslinking is used herein to mean that the functional groups of the polyimide precursors react together to form polyimide functional groups.

[0028] This enables the simple and cost-effective application of a pre-patterned resist structure on or over the electrode structure of the optoelectronic component (e.g., without requiring further steps such as etching). The polyimide resist structure also prevents or reduces pixel shrinkage in the luminous area of ​​the optoelectronic component.

[0029] In one embodiment, the polyimide resist structure comprises polyimide, ethyl lactate, and γ-butyrolactone. These components ensure good stability of the resist structure and are selected such that the organic layer structure remains free from damage. This enables good longevity of the light-emitting region of the organic optoelectronic component, which is free of pixel shrinkage or exhibits little pixel shrinkage.

[0030] In another embodiment, the polyimide resist structure is formed such that it substantially covers the electrode structure. This makes it possible to prevent current flow and thus a short circuit between two electrically conductive regions.

[0031] In another embodiment, the method further comprises forming the electrode structure on or over a substrate.

[0032] In another embodiment, the method further comprises forming an organic functional layer structure on or above the electrode structure.

[0033] In another embodiment, the method further comprises forming the electrode structure on or above the organic functional layer structure.

[0034] In various further developments, the method for producing the optoelectronic component has the same features as the optoelectronic component and vice versa.

[0035] Embodiments of the invention are illustrated in the figures and are explained in more detail below.

[0036] They show: Fig. 1A, Fig. 1B shows schematic cross-sectional views of an optoelectronic component according to various embodiments; Fig. 2 shows a flowchart of a method for producing an optoelectronic component according to various embodiments; Fig. 3A, Fig. 3B schematic top views of the light-emitting longevity of conventional optoelectronic devices; Fig. 4A, Fig. 4B Single-drop solid profile of a conventional polyimide inkjet ink and top view of the light-emitting longevity of a conventional optoelectronic device using this conventional polyimide inkjet ink; Fig. 5A, Fig. 5B Single drop solid profiles of polyimide inkjet inks according to various embodiments; Fig. 6 Top view of the light-emitting longevity of a polyimide inkjet ink according to various embodiments; and Fig. 7 Top views of optoelectronic components according to various embodiments.

[0037] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. Since components of embodiments may be positioned in a number of different orientations, the directional terminology is for the purpose of illustration and is in no way limiting. It is understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. It is to be understood that the features of the various embodiments described herein may be combined with one another unless specifically stated otherwise.The following detailed description is therefore not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims. In the figures, identical or similar elements are designated by identical reference numerals where appropriate.

[0038] Throughout this description, the terms "connected," "attached," and "coupled" are used to describe both a direct and an indirect connection, a direct or indirect connection, and a direct or indirect coupling. In the figures, identical or similar elements are provided with identical reference numerals where appropriate.

[0039] In the context of this description, an optoelectronic component can be understood as a component that emits or absorbs electromagnetic radiation by means of a semiconductor component. An organic optoelectronic component can have one, two, or more optoelectronic components. In the context of this description, an optoelectronic component can be understood as an embodiment of an electronic component, wherein the optoelectronic component has an optically active region. Optionally, an optoelectronic assembly can also have one, two, or more electronic components. An electronic component can, for example, have an active and / or a passive component. An active electronic component can, for example, have a computing, control, and / or regulating unit and / or a transistor.A passive electronic component can, for example, include a capacitor, a resistor, a diode or an inductor.

[0040] An optoelectronic component can be an electromagnetic radiation-emitting component or an electromagnetic radiation-absorbing component. An electromagnetic radiation-absorbing component can be, for example, a solar cell or a photodetector. In various embodiments, an electromagnetic radiation-emitting component can be an electromagnetic radiation-emitting semiconductor component and / or can be embodied as an electromagnetic radiation-emitting diode, as an organic electromagnetic radiation-emitting diode, as an electromagnetic radiation-emitting transistor, or as an organic electromagnetic radiation-emitting transistor. The radiation can be, for example, light in the visible range, UV light, and / or infrared light.In this context, the electromagnetic radiation-emitting component can be embodied, for example, as a light-emitting diode (LED), an organic light-emitting diode (OLED), a light-emitting transistor, or an organic light-emitting transistor. In various embodiments, the light-emitting component can be part of an integrated circuit. Furthermore, a plurality of light-emitting components can be provided, for example, housed in a common housing.

[0041] An organic optoelectronic component has an organic functional layer system, which is also synonymously referred to as an organic functional layer structure. The organic functional layer structure has or is formed from an organic substance or an organic substance mixture, which is designed, for example, to provide electromagnetic radiation from a provided electrical current or to provide an electrical current from provided electromagnetic radiation. The radiation can, for example, be light in the visible range, UV light and / or infrared light. An organic light-emitting diode is designed as a so-called top emitter and / or a so-called bottom emitter. With a bottom emitter, electromagnetic radiation is emitted from the electrically active region through the substrate.In a top emitter, electromagnetic radiation is emitted from the top of the electrically active region and not through the substrate.

[0042] For the purposes of this description, the term "material" includes an organic material, an inorganic material, and / or an organic-inorganic (hybrid) material. Furthermore, for the purposes of this description, a material mixture can be understood as something that consists of components of two or more different materials, the components of which are, for example, very finely distributed. The term "substance" can be used synonymously with the term "material."

[0043] The term "translucent" or "translucent layer" is understood to mean that a layer is permeable to electromagnetic radiation, for example to the light absorbed or generated by the optoelectronic component, for example, in one or more wavelength ranges, for example to light in a wavelength range of visible light (for example, at least in a sub-range of the wavelength range from 380 nm to 780 nm). For example, the term "translucent layer" in various embodiments is understood to mean that essentially, for example, more than 60%, of the entire amount of light coupled into a structure (for example, a layer) is also coupled out of the structure (for example, layer), with a portion of the light being scattered in the process.

[0044] The term “transparent” or “transparent layer” is understood in various embodiments to mean that a layer is permeable to electromagnetic radiation (for example, at least in a partial range of the wavelength range from 380 nm to 780 nm), wherein light coupled into a structure (for example, a layer) is also coupled out of the structure (for example, layer) without scattering or light conversion.

[0045] Fig. 1A, Fig. 1B show, in a schematic cross-sectional view, an optoelectronic component 100 according to various embodiments.

[0046] The optoelectronic component 100 comprises a first electrode structure 104 on a substrate 102, a second electrode structure 108, an organic functional layer structure 106, and a resist structure 110, 114. Optionally, the optoelectronic component 100 further comprises at least one electrical busbar 112, which is electrically and physically connected to one of the electrode structures 104, 108 and serves to improve current distribution in the electrode structure.

[0047] The resist structure 110, 114 is configured to electrically and physically isolate the first electrode structure 104 from the second electrode structure 108, thus preventing physical and direct electrical contact. Furthermore, the resist structure 110, 114 can be configured to prevent physical and direct electrical contact between the electrical busbar 112 and the organically functional layer structure 106.

[0048] In various embodiments, the resist structure 110, 114 is formed using an inkjet-printable composition, as described in more detail below. The inkjet-printable composition prevents or reduces a pixel shrinkage effect. In other words, the resist structure 110, 114 formed from the inkjet-printable composition can prevent or reduce a reduction in the size of the optically active area of ​​the organic optoelectronic component. This reduction would occur in a conventional resist structure by increasing over time, for example, by a residual solvent diffusing out in the conventional resist structure, thereby interrupting a current flow or increasing an electrical resistance.

[0049] The optoelectronic component 100 has a substrate 102, also called a carrier. The substrate 102 can be translucent or transparent. The substrate 102 serves as a carrier element for electronic elements or layers, for example, light-emitting elements. The substrate 102 can, for example, comprise or be formed from plastic, metal, glass, quartz, and / or a semiconductor material. Furthermore, the substrate 102 can comprise or be formed from a plastic film or a laminate with one or more plastic films. The substrate 102 can be mechanically rigid or mechanically flexible.

[0050] An organically functional layer structure is formed on the substrate 102. The organically functional layer structure has a first electrode structure 104 (for example, in the form of a first electrode layer 104). A first barrier layer (not shown), for example, a first barrier thin film, can be formed between the substrate 102 and the first electrode structure 104.

[0051] The first electrode structure 104 (hereinafter also referred to as first electrode 104) is electrically insulated from the first contact section 116a by means of the resist structure 110, also referred to as electrical insulation barrier 110. The second contact section 116b is electrically coupled to the first electrode 104 of the organically functional layer structure. The first electrode 104 can be formed as an anode or as a cathode. The first electrode 104 can be translucent or transparent. The first electrode 104 comprises an electrically conductive material, for example, metal and / or a conductive transparent oxide (transparent conductive oxide, TCO) or a layer stack of several layers comprising metals or TCOs. The first electrode 104 can, for example, comprise a layer stack of a combination of a layer of a metal on a layer of a TCO, or vice versa.One example is a silver layer deposited on an indium tin oxide (ITO) layer (Ag on ITO) or ITO-Ag-ITO multilayers. The first electrode 104 may alternatively or additionally comprise: networks of metallic nanowires and particles, for example, made of Ag, networks of carbon nanotubes, graphene particles and layers, and / or networks of semiconducting nanowires.

[0052] An optically functional layer structure, for example an organic functional layer structure 106, of the organic functional layer structure is formed above the first electrode 104. The organic functional layer structure 106 can, for example, have one, two, or more sublayers. For example, the organic functional layer structure 106 can have a hole injection layer, a hole transport layer, an emitter layer, an electron transport layer, and / or an electron injection layer. The hole injection layer serves to reduce the band gap between the first electrode and the hole transport layer. In the hole transport layer, the hole conductivity is greater than the electron conductivity. The hole transport layer serves to transport the holes. In the electron transport layer, the electron conductivity is greater than the hole conductivity. The electron transport layer serves to transport the electrons.The electron injection layer serves to reduce the band gap between the second electrode and the electron transport layer. Furthermore, the organic functional layer structure 22 can comprise one, two, or more functional layer structure units, each of which has the aforementioned sublayers and / or further intermediate layers.

[0053] A second electrode structure 108 of the organic functional layer structure (hereinafter also referred to as second electrode 108) is formed above the organic functional layer structure 106 and is electrically coupled to the first contact section 116a. The second electrode 108 can be formed according to one of the configurations of the first electrode 104, wherein the first electrode 104 and the second electrode 108 can be formed identically or differently. The first electrode 104 serves, for example, as the anode or cathode of the organic functional layer structure. The second electrode 108 serves, corresponding to the first electrode, as the cathode or anode of the organic functional layer structure.

[0054] The organically functional layer structure 106 is an electrically and / or optically active region. The organically functional layer structure 106 is electrically conductively connected to the first electrode structure 104 and the second electrode structure 108. In other words, the first electrode structure 104 is electrically conductively connected to the second electrode structure 108 by means of the organically functional layer structure 106. The active region is, for example, the region of the optoelectronic component 100 in which electrical current flows to operate the optoelectronic component 100 and / or in which electromagnetic radiation is generated or absorbed. In other words, an electrical current for operating the optoelectronic component 100 can flow from the first electrode structure 104 through the organically functional layer structure 106 to the second electrode structure 108, or alternatively in the opposite direction.A getter structure (not shown) can be arranged on or above the active region. The getter layer can be translucent, transparent, or opaque. The getter layer can comprise or be formed from a material that absorbs and binds substances that are harmful to the active region.

[0055] An encapsulation layer 118 of the organically functional layer structure is formed above the second electrode 108 and partially above the first contact section 116a and partially above the second contact section 116b, which encapsulates the organically functional layer structure. The encapsulation layer 118 can be formed as a second barrier layer, for example as a second barrier thin film. The encapsulation layer 118 can also be referred to as thin-film encapsulation. The encapsulation layer 118 forms a barrier against chemical contaminants or atmospheric substances, in particular against water (moisture) and oxygen. The encapsulation layer 118 can be formed as a single layer, a layer stack, or a layer structure.The encapsulation layer 118 may comprise or be formed from: aluminum oxide, zinc oxide, zirconium oxide, titanium oxide, hafnium oxide, tantalum oxide, lanthanum oxide, silicon oxide, silicon nitride, silicon oxynitride, indium tin oxide, indium zinc oxide, aluminum-doped zinc oxide, poly(p-phenylene terephthalamide), nylon 66, and mixtures and alloys thereof. Optionally, the first barrier layer on the substrate 102 may be formed corresponding to a configuration of the encapsulation layer 118.

[0056] In the encapsulation layer 118, a first recess of the encapsulation layer 118 is formed above the first contact section 116a, and a second recess of the encapsulation layer 118 is formed above the second contact section 116b. A first contact region is exposed in the first recess of the encapsulation layer 118, and a second contact region is exposed in the second recess of the encapsulation layer 118. The first contact region serves to electrically contact the first contact section 116a, and the second contact region serves to electrically contact the second contact section 116b.

[0057] An adhesive layer (not shown) is formed over the encapsulation layer 118. The adhesive layer comprises, for example, an adhesive, such as an adhesive, such as a laminating adhesive, a lacquer, and / or a resin. The adhesive layer 36 may, for example, comprise particles that scatter electromagnetic radiation, such as light-scattering particles.

[0058] A cover body (not shown) is formed over the adhesive layer. The adhesive layer serves to attach the cover body to the encapsulation layer 118. The cover body comprises, for example, plastic, glass, and / or metal. For example, the cover body can be formed substantially from glass and have a thin metal layer, for example a metal foil, and / or a graphite layer, for example a graphite laminate, on the glass body. The cover body serves to protect the conventional optoelectronic component, for example from external mechanical forces. Furthermore, the cover body can serve to distribute and / or dissipate heat generated in the conventional optoelectronic component 1.For example, the glass of the cover body can serve as protection against external influences and the metal layer of the cover body can serve to distribute and / or dissipate the heat generated during operation of the conventional optoelectronic component.

[0059] The second electrode 108 is physically insulated from the first electrode 104 by means of the resist structure 110. In other words, the first electrode structure 102 is free from direct, i.e., physical, contact with the second electrode structure 106. In other words, the resist structure 110 can be configured such that a direct current flow between two electrically conductive regions, for example, between the first electrode 104 or first electrode structure 104 and the second electrode 108 or second electrode structure 108, is prevented. Current thus flows from the first electrode 104 through the organically functional layer structure to the second electrode structure 108, or alternatively in the opposite direction.

[0060] In various embodiments, the first contact portion 112 is electrically insulated from the second electrode 108 by means of the resist structure 110. In other words, the resist structure 110 can be configured such that a direct current flow between two electrically conductive regions, for example, between the first contact portion 112 and the second electrode 108, is prevented.

[0061] In various embodiments, the optoelectronic component 100 may include at least one electrical busbar 112 on or above the first electrode 104 (shown) or organic functional layer structure 106 (not shown). In various embodiments, the electrical busbar 112 may be electrically insulated from further layers of the optoelectronic component 100 by means of a resist structure 114. In various embodiments, the electrical busbar 112 is formed such that the electrical busbar 112 is at least partially surrounded by the resist structure 114 and / or the organic functional layer structure 106. The resist structure 114 may be formed using the inkjet-printable composition.

[0062] The electrical busbar 112 can be configured to increase the lateral current distribution in the optoelectronic component 100, for example, if the first electrode 104 and / or the second electrode 108 has / have an electrical sheet resistance that would prevent a large-area formation of the optically active region. The electrical busbar 112 can, for example, be electrically connected to one of the electrodes 104, 108. In various embodiments, the optoelectronic component 100 can have two or more electrical busbars, wherein the plurality of electrical busbars can be electrically coupled to the same or, with regard to the electrical potential of the electrodes, to different electrodes.

[0063] In various embodiments, the resist structure 110, 114 comprises polyimide, ethyl lactate, and γ-butyrolactone (gamma-butyrolactone). Examples of polyimides are polysuccinimide, polybismaleimide, polybenzimidazole, polyoxadiazobenzimidazole, polyimidesulfone, and polymethacrylimide. The polyimide is selected such that the organic layer structure remains free of damage. This allows pixel shrinkage in the light-emitting region of the optoelectronic component to be avoided or reduced.

[0064] The resist structure 110, 114 is formed from an inkjet-printable composition comprising components. These components are 4 wt.% to 11 wt.% polyimide precursor, 52 wt.% to 96 wt.% of a solvent mixture containing at least 8 wt.% ethyl lactate, at least 14 wt.% γ-butyrolactone, and dimethylpropyleneurea. The percentages of the components are based on the total weight of the inkjetable composition. The components are selected such that the formation of chemical substances that have a damaging effect on the organically functional layer structure is reduced or avoided before, during, or after crosslinking the polyimide precursor in the polyimide.

[0065] The polyimide precursor, also referred to as polyimide precursor, comprises or consists of chemical molecule(s). These molecules have chemical functional groups that react with each other through polycondensation and directly form a chemical bond, representing an imide functional group. The chemical functional groups that react with each other are, for example, dianhydride groups with diamine groups, dianhydride groups with diisocyanate groups, or acid groups, such as tetrahydrocarboxylic acid with diamine groups. The reaction can occur via an intermediate such as poly(amic acid). The polyimide precursor can be aliphatic or aromatic, linear or branched. The polyimide precursor is, for example, a positively or negatively photosensitive polyimide precursor. For example, the polyimide precursor is an aromatic, positively photosensitive polyimide precursor.The polyimide precursor is, for example, the polyimide precursor contained in DL-1000 from Toray. The polyimide precursor is selected to be compatible with the organic functional layer structure. In other words, the polyimide precursor in contact with the organic functional layer structure is selected to ensure that the organic layer structure remains free of damage. Furthermore, the polyimide precursor is selected to ensure that the organic layer structure remains free of damage during or after crosslinking of the polyimide precursor in the polyimide. This ensures that the polyimide resist structure retains the organic layer structure free of damage. This allows pixel shrinkage in the luminous area of ​​the optoelectronic component to be avoided or reduced.

[0066] In various embodiments, the inkjet-printable composition comprises polyimide precursor in a range from 4 wt.% to 11 wt.% based on the total weight of the inkjet-printable composition, for example at least 5 wt.%, at least 6 wt.%, at least 7 wt.%, at least 8 wt.%, at least 9 wt.%, for example at most 10 wt.%, at most 9 wt.%, at most 8 wt.%, at most 7 wt.%. For example, the inkjet-printable composition comprises polyimide precursor in amounts of 4.45 wt.%, 5.56 wt.%, 7.43 wt.%, 9.94 wt.%.

[0067] The wt% refers to the weight fraction of the polyimide precursor in the total inkjet-printable composition. The sum of all components of the inkjet-printable composition cannot exceed 100 wt%.

[0068] The inkjet-printable composition also comprises 52 wt.% to 96 wt.% of a solvent mixture based on the total weight of the inkjet-printable composition, for example, at least 66 wt.%, at least 75 wt.%, for example, at most 89 wt.%, at most 82 wt.%. For example, the inkjet-printable composition comprises the solvent mixture in amounts of 85.42 wt.%, 89.10 wt.%, 91.84 wt.%, 93.47 wt.%.

[0069] The solvent mixture comprises at least 8 wt% ethyl lactate based on the total weight of the inkjetable composition, for example at least 9 wt%, at least 10 wt%, at least 11 wt%, at least 14 wt%. For example, the inkjet-printable composition comprises ethyl lactate in amounts of 8.59 wt%, 10.76 wt%, 14.37 wt%, or 19.22 wt%.

[0070] The solvent mixture comprises at least 14 wt% γ-butyrolactone based on the total weight of the inkjetable composition, for example at least 20 wt%, at least 30 wt%, at least 50 wt%, at least 60 wt%, and for example at most 88 wt%, at most 80 wt%, at most 70 wt%. For example, the inkjet-printable composition comprises γ-butyrolactone in amounts of 14.53 wt%, 18.18 wt%, 24.28 wt%, 32.47 wt%, 44.71 wt%, 55.95 wt%, 66.20 wt%, 74.73 wt%.

[0071] In a non-claimed embodiment, the solvent mixture consists of ethyl lactate and γ-butyrolactone, for example, 14.37 wt.% ethyl lactate and 74.73 wt.% γ-butyrolactone based on the total weight of the inkjetable composition, for example, 19.22 wt.% ethyl lactate and 66.20 wt.% γ-butyrolactone based on the total weight of the inkjetable composition. Depending on the commercial origin of the ethyl lactate and γ-butyrolactone, for example, the degree of purity, the solvent mixture may contain varying proportions of impurities that are neglected in this analysis. Ethyl lactate and γ-butyrolactone are high-boiling solvents. This allows for low levels of outgassing from the solvent mixture before, during, or after crosslinking the polyimide precursor into polyimide.This ensures that the organic functional layer structure remains free from damage and that a pixel shrinkage effect in the luminous area of ​​the optoelectronic component is avoided or reduced.

[0072] In various embodiments, the solvent mixture is free of water or contains at most 1.00 wt.% water, for example 0.90 wt.% or 0.70 wt.% based on the total weight of the inkjetable composition.

[0073] In various embodiments, the inkjet-printable composition has a viscosity, measured using a standard rheometer, in the range of approximately 2 mPa.s to approximately 25 mPa.s, for example, at least approximately 4 mPa.s, at least approximately 5 mPa.s, at least approximately 6 mPa.s, and for example, at most approximately 25 mPa.s, at most approximately 20 mPa.s, or at most approximately 15 mPa.s. This enables high fluidity of the inkjet-printable composition. This causes the inkjet-printable composition to be homogeneously printed on a material to be printed using an inkjet process.

[0074] In various embodiments, the solvent mixture further comprises at least one solvent, for example one, two, three, four different solvents, etc. The at least one solvent can be selected from the group comprising or consisting of diethylene glycol, acetophenone, benzonitrile, dimethyl sulfoxide, cyclohexanone, and anisole. The at least one solvent is, for example, diethylene glycol. Depending on the commercial origin of the solvents, the solvent mixture can contain different proportions of impurities that are neglected in the analysis. This enables better adaptation of the solvent mixture to the desired properties of the inkjet-printable composition, such as viscosity, density of the liquid droplet, surface tension, Reynolds number, Weber number, and compatibility with the organically functional layer structure.This avoids or reduces the pixel shrinkage effect in the light-emitting area of ​​the optoelectronic component.

[0075] Different solvents can also be considered to be chemically identical solvents but with different degrees of purity, for example Chromasolv, Anhydrous, Technical, etc.

[0076] The solvent mixture is selected to ensure good, homogeneous printing. In other words, the solvent mixture is selected to ensure sufficient fluidity, making it compatible with an inkjet printing process.

[0077] The solvent mixture is also selected such that the particle flow in the inkjet printable composition is such that a homogeneous polyimide precursor coating is present on the printed material.

[0078] The solvent mixture is also selected to exhibit low initial evaporation. This ensures that the inkjet-printable composition is free from drying out before or during printing. This allows the printable properties of the inkjet-printable composition to be ensured.

[0079] The solvent mixture is also selected to ensure good and homogeneous drying of the inkjet-printable composition. In other words, the composition of the inkjet-printable composition is selected to result in a sufficiently solid state of the composition, so that it is free from sagging or deformation on the printed material.

[0080] The solvent mixture is also selected such that it has a damaging effect on the organically functional layer structure before, during, or after its partial or complete evaporation. This prevents or reduces pixel shrinkage in the luminous area of ​​the optoelectronic component.

[0081] In various embodiments, the inkjet-printable composition further comprises N-methyl-2-pyrrolidone based on the total weight of the inkjet-printable composition, for example, at most 1.00 wt. %, at most 0.90 wt. %, at most 0.80 wt. %. For example, the inkjet-printable composition comprises N-methyl-2-pyrrolidone in amounts of 0.66 wt. %, 0.50 wt. %, 0.37 wt. %, 0.3 wt. %. This catalyzes the polycondensation of the polyimide precursor into polyimide and / or produces fewer by-products. This enables a homogeneous, better-structured polyimide resist structure.

[0082] In various embodiments, the inkjet-printable composition further comprises additives in the range from 1.80 wt.% to 4.00 wt.% based on the total weight of the inkjet-printable composition, for example at least 2.00 wt.%, at least 2.30 wt.%, at least 2.50 wt.%, and for example at most 3.80 wt.%, at most 3.60 wt.%, at most 3.40 wt.%. For example, the inkjet-printable composition comprises additives in amounts of 2.25 wt.%, 3.00 wt.%. The additives are, for example, ionic dispersants that increase the stability of the dispersion in the inkjet-printable composition. Alternatively or additionally, the additives can, for example, have dewetting properties. This prevents the wetting of the printhead nozzle plates in the inkjet printing core. Alternatively or additionally, the additives can, for example, be surfactants.This has the effect of extending the decap time without affecting the drying time on the printed material. The term decap time is used herein to mean the period of time during which an inkjet nozzle can be left idle before the inkjet nozzle begins to fire an ink drop improperly, for example when no drop is fired, firing occurs with misdirection, with ink loss, or an unacceptable reduction in velocity occurs. Alternatively or additionally, the additives may be, for example, conductive aids. This enables good conductivity of the droplets of inkjet printable composition and the droplets to be deflected. Alternatively or additionally, the composition may comprise further additives, for example antifoams, wetting agents, light stabilizers or additives to adjust the desired viscosity.

[0083] In various embodiments, the single-drop solid profile of the inkjet-printable composition on a material has a thickness in a range of 300 µm to 700 µm and a height in a range of 400 µm to 600 µm. The material may be substantially the same as one of the embodiments described above.

[0084] Examples of inkjet printable compositions are presented below.

[0085] For example, an inkjet printable composition A not according to the invention consists of the following components: - 5.56 wt.% polyimide precursor, - 55.95% by weight γ-butyrolactone, - 10.76 wt% ethyl lactate, - 25.13 wt% diethylene glycol, - 0.37% by weight of N-methyl-2-pyrrolidone, - 2.23 wt% additives.

[0086] For example, an inkjet printable composition B not according to the invention consists of the following components: - 7.43 wt.% polyimide precursor, - 74.73% by weight γ-butyrolactone, - 14.37% w / w ethyl lactate, - 0.50% by weight of N-methyl-2-pyrrolidone, - 2.97 wt% additives.

[0087] For example, an inkjet printable composition C not according to the invention consists of the following components: - 9.94 wt.% polyimide precursor, - 66.20% by weight γ-butyrolactone, - 19.22% w / w ethyl lactate, - 0.66% by weight of N-methyl-2-pyrrolidone, - 3.98 wt% additives.

[0088] For example, an inkjet printable composition D not according to the invention consists of the following components: - 4.45 wt.% polyimide precursor, - 44.71% by weight of γ-butyrolactone, - 8.59% w / w ethyl lactate, - 40.17 wt% diethylene glycol, - 0.30% by weight of N-methyl-2-pyrrolidone, - 1.78 wt% additives.

[0089] For example, the inkjet-printable composition is a mixture of DL-1000 from Toray and a solvent. DL-1000 from Toray is a commercial polyimide precursor solution for screen printing. DL-1000 comprises about 15 wt.% polyimide precursor, about 29 wt.% ethyl lactate, about 49 wt.% γ-butyrolactone, about 1 wt.% N-methyl-2-pyrrolidone, and about 6 wt.% additives.

[0090] Examples of inkjet printable compositions prepared from DL-1000 are presented below.

[0091] For example, an inkjet printable composition E not according to the invention consists of the following components: - 37.10 wt% DL-1000, - 37.77 wt% γ-butyrolactone and - 25.13 wt% diethylene glycol, resulting in the following composition: - 5.562 wt.% polyimide precursor, - 18.18 wt% γ-butyrolactone from DL-1000, - 37.77% by weight γ-butyrolactone, - 10.76 wt% ethyl lactate, - 25.13 wt% diethylene glycol, - 0.37% by weight of N-methyl-2-pyrrolidone, - 2.23 wt% additives.

[0092] For example, an inkjet printable composition F not according to the invention consists of the following components: - 49.55 wt% DL-1000 and - 50.45 wt% γ-butyrolactone, resulting in the following composition: - 7.43 wt.% polyimide precursor, - 24.28 wt% γ-butyrolactone from DL-1000, - 50.45% by weight γ-butyrolactone, - 14.37% w / w ethyl lactate, - 0.50% by weight of N-methyl-2-pyrrolidone, - 2.97 wt% additives.

[0093] For example, an inkjet printable composition G not according to the invention consists of the following components: - 66.27 wt% DL-1000 and - 33.73 wt% γ-butyrolactone, resulting in the following composition: - 9.94 wt.% polyimide precursor, - 32.47 wt% γ-butyrolactone from DL-1000, - 33.73% by weight γ-butyrolactone, - 19.22% w / w ethyl lactate, - 0.66% by weight of N-methyl-2-pyrrolidone, - 3.98 wt% additives.

[0094] For example, an inkjet printable composition H not according to the invention consists of the following components: - 29.64 wt% DL-1000, - 30.18 wt% γ-butyrolactone and - 40.17 wt% diethylene glycol, resulting in the following composition: - 4, 450 wt.% polyimide precursor, - 14.53 wt% γ-butyrolactone from DL-1000, - 30.18% by weight γ-butyrolactone, - 8.59% w / w ethyl lactate, - 40.17 wt% diethylene glycol, - 0.30% by weight of N-methyl-2-pyrrolidone, - 1.78 wt% additives.

[0095] In various embodiments, on or above the electrically functional structure 120 (illustrated in Fig. 1B) an encapsulation structure 118 may be formed.

[0096] The encapsulation structure 118 may be or include a cover, which may be, for example, a glass cover, a metal foil cover, or a sealed plastic film cover.

[0097] The encapsulation structure 118 may be hermetically sealed with respect to water and / or oxygen.

[0098] Fig. 2 shows a flowchart of a method 200 for producing an optoelectronic component 100 according to various embodiments. The method 200 can be carried out according to the embodiments of the inkjet-printable composition or the optoelectronic component described herein.

[0099] The method 200 for producing an optoelectronic component 100 comprises applying 202 an inkjet-printable composition onto or over an electrode structure by means of an inkjet process, and crosslinking 204 the inkjet-printable composition such that a polyimide resist structure is formed.

[0100] The inkjet-printable composition can essentially correspond to one of the described embodiments. This results in the method using an inkjet-printable composition selected such that its viscosity is suitable for an inkjet process that results in a homogeneous polyimide precursor coating, that it exhibits homogeneous drying, and that it is compatible with the organically functional layer structure. In other words, the inkjet-printable composition used in the method for producing an optoelectronic component is selected such that it enables very good and homogeneous printing on the printing material, that it exhibits good durability, and that it leaves the organically functional layer structure free from damage.

[0101] The electrode structure may substantially correspond to an embodiment of electrodes and / or busbar described above.

[0102] In various embodiments, the inkjet process is a contactless or non-contact method for applying a composition to a material to be printed. For example, the inkjet process can be spraying, dripping, or inkjet printing. This makes it possible to provide a very cost-effective printing process, since the grid material can be applied in a pre-structured manner to the surface of the other material, rather than depositing grid material as in lithography. This results in low material consumption, which increases environmental and occupational safety.

[0103] In various embodiments, crosslinking the inkjet-printable composition involves converting the polyimide precursor into polyimide. Alternatively or additionally, crosslinking involves a polycondensation reaction of the molecules comprised in the polyimide precursor. Alternatively or additionally, crosslinking involves a polymerization reaction of the polyimide precursor with other components of the inkjet-printable composition, for example, with additives and / or N-methyl-2-pyrrolidone. This enables the polyimide coating to form a polyimide resist structure on the printed material. This results in the polyimide resist structure having properties such as chemical resistance, heat resistance, radiation resistance, good electrical insulation, and, at the same time, low outgassing. This avoids or reduces damage to the organically functional layer structure.This allows the luminous surface of the optoelectronic component to exhibit a pixel shrinkage effect.

[0104] In various embodiments, crosslinking is carried out by heating, UV radiation, or microwave radiation. For example, crosslinking is carried out by heating, for example in a convection oven, for example at a temperature in the range of 200°C to 250°C at atmospheric pressure for a period of time in the range of 60 minutes to 120 minutes, for example 90 minutes.

[0105] In various embodiments, the polyimide resist structure comprises polyimide, ethyl lactate, and γ-butyrolactone. Ethyl lactate and γ-butyrolactone are high-boiling solvents. This enables a stable structure of the polyimide precursor coating during evaporation of the solvent mixture. This also allows for low levels of outgassing from the solvent mixture before, during, or after crosslinking of the polyimide precursor in the polyimide. This ensures that the organically functional layer structure remains free of damage and that a pixel shrinkage effect in the luminous area of ​​the optoelectronic component is avoided or reduced.

[0106] In various embodiments, the polyimide resist structure is formed such that it substantially covers the electrode structure. In other words, the polyimide resist structure can partially or completely bypass the electrodes and / or busbar.

[0107] In various embodiments, method 200 further includes forming 206 the electrode structure on or over a substrate. The substrate may substantially correspond to one of the embodiments described above.

[0108] In various embodiments, method 200 further comprises forming 208 an organic functional layer structure on or above the electrode structure. The organic functional layer may substantially correspond to one of the embodiments described above.

[0109] In various embodiments, the formation 208 of the organically functional layer structure on or above the electrode structure is carried out before or after the application 202 of the inkjet-printable composition on or above the electrode structure and the crosslinking 204 of the inkjet-printable composition.

[0110] In various embodiments, the method 200 further comprises forming 210 the electrode structure on or above the organic functional layer structure.

[0111] In various embodiments, the formation 210 of the electrode structure on or over the organically functional layer structure is carried out before or after the application 202 of the inkjet-printable composition on or over the electrode structure and the crosslinking 204 of the inkjet-printable composition.

[0112] In various embodiments, the formation 208 of the organic functional layer structure on or above the electrode structure and the formation 210 of the electrode structure on or above the organic functional layer structure are carried out before or after the application 202 of the inkjet printable composition on or above the electrode structure and the crosslinking 204 of the inkjet printable composition.

[0113] Fig. 3A, Fig. 3B show schematic top views of the light-emitting longevity of conventional optoelectronic devices.

[0114] An optoelectronic component typically has a resist frame, also called a grid, that defines the pixel structure. In conventional optoelectronic components, such as OLEDs, the resist frame is formed from materials selected from silicon oxide, silicon nitride, polyimide layers, acrylic resins, novolak photoresists (cresol resists), and polybenzoxazole.

[0115] Fig. 3A shows the active light-emitting area of ​​OLEDs 300a, on which a grid of polyimide 302a, novolak photoresist 304a and acrylic resin 306a is deposited on a substrate of the OLEDs by photolithography.

[0116] Fig. Figure 3B shows the active luminous area of ​​OLEDs 300b after 72 hours at 80 °C under dry conditions.

[0117] The OLED with a polyimide 302b resist structure was found to retain the entire active luminous area, indicating an OLED that is free from damage caused by the resist structure.

[0118] The OLED with a resist structure made of alkyl resin 304b was found to have a reduction of the light-emitting area of ​​the entire active luminous surface by 47%.

[0119] The OLED with a resist structure made of alkyl resin 306b was found to have a reduction of the light-emitting area of ​​the entire active luminous surface by 64%.

[0120] Fig. Figures 4A, B show the single-drop solid profile of a conventional polyimide inkjet ink and a top view of the light-emitting longevity of a conventional optoelectronic device formed from this conventional polyimide inkjet ink.

[0121] Fig. Figure 4A shows the single-drop solid profile of the commercial polyimide inkjet ink PI-6302 from JNC Corp. 400a. The x-axis 402 represents the measured width (in micrometers) and the y-axis 404 represents the measured height of the droplet (in micrometers). The single droplet of the polyimide inkjet ink PI-6302 has a width of 65 µm and a height of 0.5 µm.

[0122] The polyimide inkjet ink PI-6302 was applied to a luminous surface 400b.

[0123] Fig. 4B shows a top view of the luminous surface during the application of a drop 406 thereto. After two weeks in the oven at a temperature of 105°C, the area of ​​the drop shows an increase of 50%, so that the luminous surface has a reduction in its light-emitting area 408.

[0124] Fig. 5A, Fig. 5B show the single-drop solid profile of two polyimide inkjet inks according to various embodiments. The polyimide inkjet inks essentially correspond to an inkjet-printable composition described above. In these embodiments, the layer thickness ranges from 500 nm to 800 nm with a 10 pL printhead, a substrate temperature of 40°C, and a metal substrate.

[0125] Fig. Figure 5A shows the single-drop solid profile of a polyimide inkjet ink 500a formed by mixing a 1:1 solution of DL-1000:γ-butyrolactone to which 5 wt% diethylene glycol was added. The x-axis 502 represents the measured width (in micrometers) and the y-axis 504 represents the measured height of the drop (in micrometers). The single drop of the inventive polyimide inkjet ink 500a has a width of approximately 45 µm and a height of approximately 0.4 µm.

[0126] Fig. Figure 5B shows the single-drop solid profile of a polyimide inkjet ink 500b obtained by mixing a 1:1 solution of DL-1000:γ-butyrolactone with 10 wt% diethylene glycol added. The x-axis 502 represents the measured width (in micrometers) and the y-axis 504 represents the measured height of the drop (in micrometers). The single drop of the inventive polyimide inkjet ink 500b has a width of approximately 50 µm and a height of approximately 0.3 µm.

[0127] Fig. Figure 6 illustrates the top view of the light-emitting longevity of a polyimide inkjet ink according to various embodiments. The polyimide inkjet inks substantially correspond to an inkjet-printable composition described above.

[0128] The polyimide inkjet ink 500b was applied to a luminous surface 600. The Fig. Figure 6 shows a top view of the luminous surface during the deposition of a droplet 602. After four weeks in the oven at a temperature of 105°C, the droplet surface is free of growth. The luminous surface is free of reductions in its light-emitting area 604 and thus free of the pixel shrinkage effect.

[0129] Fig. 7 illustrates top views of optoelectronic components according to various embodiments. The optoelectronic components can substantially correspond to one of the above embodiments. Fig. Figure 7 shows that the polyimide inkjet inks 700 according to the invention are well printable on a substrate and that they enable very good and homogeneous printing.

[0130] Inkjet printable compositions according to the invention comprise: • 4 wt% to 11 wt% polyimide precursor, • 52% to 96% by weight of a solvent mixture comprising: • at least 8% w / w ethyl lactate, and • at least 14% by weight of γ-butyrolactone, • Dimethylpropyleneurea where all percentages are given relative to the total weight of the inkjetable composition, wherein the composition has a viscosity, measured by a standard rheometer at a temperature in a range of 20°C to 30°C, in a range of about 2 mPa.s to about 25 mPa.s.

[0131] According to a second embodiment, the inkjet-printable composition according to the first embodiment can be designed such that the solvent mixture further comprises at least one solvent from the group of solvents: • Diethylene glycol, • Acetophenone, • Benzonitrile, • Dimethyl sulfoxide, • Cyclohexanone, • Anisole, • preferably diethylene glycol.

[0132] According to a third embodiment, the inkjet-printable composition according to the first or second embodiment can be designed such that the composition further comprises N-methyl-2-pyrrolidone, preferably at most 1 wt.% based on the total weight of the inkjetable composition.

[0133] According to a fourth embodiment, the inkjet-printable composition according to the first to third embodiments can be designed such that the composition further comprises additives in the range of 1.8 wt% to 4 wt% based on the total weight of the inkjetable composition.

[0134] According to a fifth embodiment, the composition according to the first to fourth embodiments can be designed such that the composition is an inkjet ink.

[0135] According to a sixth embodiment, the inkjet printable composition can be used in an organic optoelectronic component comprising: • a first electrode on or above a substrate, • an organically functional layered structure, • a second electrode, and • a resist structure formed from the inkjet printable composition according to the first to fifth embodiments.

[0136] According to a seventh embodiment, the component according to the sixth embodiment can be designed such that the resist structure comprises polyimide, ethyl lactate and γ-butyrolactone.

[0137] According to an eighth embodiment, the device according to the sixth embodiment or the seventh embodiment may be configured such that the resist structure physically isolates the electrodes from each other.

[0138] According to a ninth embodiment, a method for producing an optoelectronic component may comprise: - applying an inkjet-printable composition on or over an electrode structure by means of an inkjet process, wherein the inkjet-printable composition is configured according to the first to fifth embodiments; and - Crosslinking the inkjet printable composition to form a polyimide resist structure.

[0139] According to a tenth embodiment, the method according to the sixth embodiment may be configured such that the polyimide resist structure comprises polyimide, ethyl lactate and γ-butyrolactone.

[0140] According to an eleventh embodiment, the method according to the ninth embodiment or the tenth embodiment may be configured such that the polyimide resist pattern is formed to substantially cover the electrode pattern.

[0141] According to a twelfth embodiment, the method according to the ninth to eleventh embodiments can be designed such that it further comprises forming the electrode structure on or above a substrate.

[0142] According to a thirteenth embodiment, the method according to the ninth to twelfth embodiments can be designed such that it further comprises forming an organically functional layer structure on or above the electrode structure.

[0143] According to a fourteenth embodiment, the method according to the ninth to thirteenth embodiments can be designed such that it further comprises forming the electrode structure on or above the organically functional layer structure.

Claims

[1] An inkjet printable composition comprising: • 4 wt% to 11 wt% polyimide precursor, • 52% to 96% by weight of a solvent mixture comprising: • at least 8% by weight ethyl lactate, • at least 14% by weight of γ-butyrolactone, and • Dimethylpropyleneurea where all percentages are given relative to the total weight of the inkjetable composition, wherein the composition has a viscosity, measured by means of a standard rheometer at a temperature in a range of 20°C to 30°C, in a range of 2 mPa·s to 25 mPa·s. [2] The inkjet printable composition of claim 1, wherein the solvent mixture further comprises at least one solvent selected from the group consisting of: • Diethylene glycol, • Acetophenone, • Benzonitrile, • Dimethyl sulfoxide, • Cyclohexanone, • Anisole, • preferably diethylene glycol. [3] Inkjet printable composition according to any one of claims 1 to 2, wherein the composition further comprises N-methyl-2-pyrrolidone, preferably at most 1 wt.% based on the total weight of the inkjet printable composition. [4] The inkjet printable composition according to any one of claims 1 to 3, wherein the composition further comprises additives in the range of 1.8 wt% to 4 wt% based on the total weight of the inkjet printable composition. [5] Use of an inkjet-printable composition according to one of claims 1 to 4 in an organic optoelectronic component (100) comprising: • a first electrode (104) on or above a substrate (102), • an organically functional layered structure (106), • a second electrode (108), and • a resist structure (110, 114) formed from the inkjet printable composition. [6] Use according to claim 5, wherein the resist structure (110, 114) physically isolates the electrodes (104, 108) from each other. [7] Method for producing (200) an optoelectronic component, the method (200) comprising: - applying an inkjet-printable composition on or over an electrode structure by means of an inkjet process (202), wherein the inkjet-printable composition is configured according to one of claims 1 to 4; and - crosslinking the inkjet printable composition to form a polyimide resist structure (204). [8] The method according to claim 7, wherein the polyimide resist pattern is formed to cover the electrode pattern. [9] The method of any of claims 7 and 8, further comprising forming the electrode structure on or over a substrate (206). [10] A method according to any one of claims 7 to 9, the method further comprising: Forming an organic functional layer structure on or above the electrode structure (208). [11] A method according to any one of claims 7 to 10, the method further comprising: Forming the electrode structure on or above the organic functional layer structure (210).

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