SI24593A - The manufacturing process of the organic light emitting diode - Google Patents

Abstract

According to the invention, a process for the production of organic light-emitting diodes is envisaged, in which the transport layers and the emulsion layer are applied to the suitable substrate, especially the glass surface or film with the previously applied anode, and then the cathode space is formed and the cathode itself is inserted, from the eutectic mixture of gallium and indium. The application of the transport layer and emulsion layer is carried out according to the invention with a flexicotype.

Description

The process of making an organic LED

The invention relates to a process for the production of an organic light-emitting diode (OLED). Such inventions are classified in the field of electrical engineering as luminaries, and more specifically in the processes of producing electroluminescent light sources.

The invention is based on the problem of how to refine the process of making an organic LED so that it can run faster and thus, in large-scale production, the diode production time will be significantly shorter than previously known processes.

The Applicant is aware of a process for the production of organic light emitting diodes in which a suitable substrate, in particular a glass surface or foil, with a pre-applied anode consisting of a solid solution is typically 90% by weight of indium (III) oxide And ₂ O3 and 10 wt. % of tin (IV) oxide SnO ₂ (also known to those skilled in the art by the abbreviation ITO, which is derived from the English professional terminology Indium Tin Oxide), a poly (3,4-ethylenedioxythiophene) hardening transport layer is applied in hot air. poly (styrenesulfonate) (abbreviated as PEDOT: PSS), and an emissive layer consisting of a UV-curable ruthenium complex. In this case, the application of a layer of UV-curable ruthenium complex is done by spraying, either by spin coating or by droplet printing using a so-called ink jet printer. This is followed by the creation of a space for the cathode and the insertion of the cathode itself, using the so-called. self-adhesive masks for the cathode, the ITO layer being applied to the first ie lower mask, while the cathode itself consists of a eutectic mixture of gallium and indium. This process is characterized by the fact that the transport layer (PEDOT.PSS) and the emission layer from the UV-curable ruthenium complex are applied by spin coating or. Droplet printing with the help of the so-called ink jet printer is therefore relatively slow and therefore suitable especially for smaller areas, individually or. laboratory use, but not for large-scale production.

The invention relates to a method of manufacturing organic light-emitting diodes, in which a suitable substrate, in particular a glass plate or polymer substrate in the form of a plate or foil, with a pre-applied anode consisting of a solid solution of at least about 90% by weight of indium (III) oxide And ₂ O ₃ and ut. 10% of the tin (IV) oxide SnO ₂ (ITO) is applied in a hot air-hardened transport layer consisting of a mixture of sodium sulfate polystyrene and poly (3,4-ethylenedioxythiophene) poly (styrenesulfonate) (PEDOT: PSS), and the emission layer, consisting of a UV-curable ruthenium complex, followed by the formation of a cathode space and then the introduction of a cathode from a eutectic mixture of gallium and indium by the so-called. cathode self-adhesive masks, with an electrically conductive layer (ITO) also applied to the first, ie lower, mask.

However, the process according to the invention is characterized by the fact that it is applied in the hot air of the drying or drying process. The hardening transport layer (PEDOT; PSS) and the emissivity layer from the UV hardening ruthenium complex are executed by flexographic printing.

In one of the possible embodiments of the process of the invention, a mixture of tris (2,2′bipyridyl) dichloro-ruthenium (II) hexahydrate, ammonium hexafluorophosphate and acetonitrile is used as the UV-curable ruthenium complex in the step of applying the emissive layer to flexoprint.

In an alternative embodiment of the process of the invention, a mixture of tris (2,2'bipyridyl) dichloro-ruthenium (II) hexahydrate, ammonium hexafluorophosphate and dimethyl sulfoxide is used in the step of applying the emissive layer with flexoprint as a UV-curable ruthenium complex.

OLED Organic LED (abbreviated as Organic Light Emitting Diode, often also Light Emitting Polymer (LEP) or Organic Electro Luminescence (OEL), is any organic element based light-emitting diode (LED) that emits light in contact with electricity The classic LED is semiconductor rather than organic, and the layers of OLED technology are made up of organic matter.

The modern organic diode consists of a radiating semiconductor (n) layer and a semiconductor (p) layer between the anode and the cathode. For better efficiency, the diodes may also consist of several layers.

The voltage on the electrodes causes the charge to shift, the electrons collect in the radiating layer, and there is a surplus of positive charge behind them in the conducting layer. Despite the electrode voltage, the positive and negative charges are attracted. When a positive and negative charge is encountered (at the p-n junction), the excesses are eliminated and the energy generated is released in the form of light. The wavelength (or color) of light depends on the materials of the two semiconductor layers in the diode.

Example

In the manufacture of organic light emitting diode (OLED), tin-doped indium oxide (ITO) was used on a suitable substrate, namely glass or polymer film. ITO is a solid solution consisting of at least about 90% by weight of indium (III) oxide Ιη ₂ θ3 and 10 wt. % of tin (IV) oxide SnO ₂ and was used for good electrical conductivity and transparency. In thin layers, it was applied to substrates by physical processes from the vapor phase.

We further used the hot air to dry or dry. hardener PEDOT from manufacturers Clevious and Sigma-Aldrich, which was previously diluted with iso-2-propanol for better adhesion. PEDOT Mixture Used: PSS, namely poly (3,4 ethylenedioxythiophene) poly (styrenesulfonate), is a polymeric mixture of two ionic monomers. One part of this mixture consists of sodium sulfate polystyrene, which is sulfonated polystyrene. The other part of poly (3,4-ethylenediooxythiophene) or PEDOT is a bound polymer and carries positive charges based on polythiophene. Together, the charged macromolecules form a macromolecular salt.

UV-curable ruthenium complex was used for printing the emission layer, which is also used in the spin coating technique, which is a mixture of tris (2,2'-bipyridyl) dichloro-ruthenium (II) hexahydrate , ammonium hexafluorophosphate and acetonitrile. An alternative is the UV-curable ruthenium ink jet complex, a mixture of tris (2,2′-bipyridyl) dichloro-ruthenium (II) hexahydrate, ammonium hexafluorophosphate and dimethyl sulfoxide.

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The eutectic mixture of gallium and indium was used for the cathode, in direct contact with the emissive layer of said ruthenium complex and the ITO anode layer on the lower self-adhesive polymer mask to form the cathode space.

The OLED thus produced consisted of an anode (ITO) on a suitable substrate, a transport layer (PEDOT: PSS), an emissive layer from a ruthenium complex that emits light, and a cathode from a eutectic mixture of gallium and indium. These layers were sandwiched between the polymer substrate, and also between the glass and the polymer substrate, optionally further coated with an encapsulation protective layer, so that oxygen and moisture were prevented, while at the same time ensuring the protection of said layers against external physical effects and injuries. The assembly thus obtained was able to be connected to a DC source.

The components that make up the functioning OLED, namely in the hot air, dry out. the hardened transport layer (PEDOT: PSS) and the emissive layer of the UV hardened ruthenium complex were flexibly applied to the substrate in the form of a polymeric film with a pre-applied anode layer (ITO). In the first case, the PEDOT: PSS and UV-curable ruthenium complex were applied to the previously applied ITO layer in hot air, and in the second case, the emission layer from the UV-curable ruthenium complex was applied to the previously applied ITO layer and PEDOT: PSS.

This resulted in a working OLED in which the transport layer (PEDOT: PSS) and the emissive layer of the UV-curable ruthenium complex were applied flexibly in hot air. The quality of the OLED fabrication itself, as well as its efficiency in terms of luminosity, was comparable to OLEDs, which were performed using known methods of depositing the transport layer and the emission layer by the technique of spin coating or droplet printing.

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Polymer film provides OLED with more flexibility, more flexibly without stopping. In addition, we did not need a clean room to make one, and the cleanliness of the surroundings greatly contributes to the longer life of the manufactured diode. The application of said transport layer and the emission layer in the flexography technique is sufficiently uniform and of a suitable thickness for producing a working OLED, in addition, the method according to the invention enables the application of said transport layer and the emission layer to a larger surface, which enables significantly higher production productivity compared to the previously known ones. procedures.

Claims (3)

A method of manufacturing organic light-emitting diodes in which a suitable substrate, in particular a glass plate or polymer substrate in the form of a plate or foil, is pre-applied with an anode consisting of a solid solution of at least about 90% by weight of indium (III) oxide And ₂ O3 and 10 wt. % of tin (IV) oxide SnO ₂ (ITO) is applied in hot air to dry or dry. curable transport layer consisting of a mixture of sodium sulphate of polystyrene and poly (3,4-ethylenedioxythiophene) poly (styrenesulfonate) (PEDOT: PSS), and an emissive layer consisting of a UV-curable ruthenium complex, followed by the formation of a cathode space and thereafter cathodes from the eutectic mixture of gallium and indium by the so-called. cathode self-adhesive masks, wherein an electrically conductive layer (ITO) is also applied on the first ie lower mask, characterized in that the step of applying the hot air-drying transport layer (PEDOT: PSS) and the emissivity layer from the UV-curable ruthenium complex execute with flexography. Method according to claim 1, characterized in that in the step of applying the emissive layer with flexoprint, a mixture of tris (2,2′-bipyridyl) dichloro-ruthenium (II) hexahydrate, ammonium hexafluorophosphate and acetonitrile is used as the UV-curable ruthenium complex. Method according to claim 1, characterized in that in the step of applying the emissive layer with flexoprint, a mixture of tris (2,2'-bipyridyl) dichloro-ruthenium (II) hexahydrate, ammonium hexafluorophosphate and dimethyl sulfoxide is used as a UV-curable ruthenium complex .