JP6411036B2 - Organic electronic devices - Google Patents

Description

  The present invention includes a metal anode and a hole injection layer, and further includes a self-assembled monolayer (SAM) between the metal anode and the hole injection layer, and is a wettable corrosion inhibitor. The present invention relates to an organic electronic device that fulfills the functions of and a method for manufacturing the device.

  Organic electronic devices provide many potential advantages, such as inexpensive, low temperature, large scale fabrication on a variety of substrates (such as glass and plastic). Examples of organic electronic devices include organic light emitting diodes, organic thin film transistors, organic photovoltaic devices, organic photosensors, and organic memory array devices.

  Organic light-emitting diode displays offer additional advantages compared to other display technologies, in particular bright, colorful and fast switching, resulting in a wide viewing angle. OLED devices, which include herein organometallic devices and devices that include one or more phosphors, depend on the materials used in a range of colors and in multicolor displays It can be made using either polymers or small molecules. For general background information see, for example, “Organic Light”, which describes WO 90/13148, WO 95/06400, WO 99/48160 and US 4,539,570, as well as several materials and devices (both small molecules and polymers). Reference may be made to Emitting Materials and Devices "by by Zhigang Li and Hong Meng, CRC Press (2007), ISBN 10: 1-57444-574X.

  In its most basic form, an organic light emitting diode (OLED) is configured with a light emitting layer disposed between an anode and a cathode. In many cases, a hole injection layer is incorporated between the anode and the light emitting layer. This reduces the energy difference between the work function of the anode [eg indium tin oxide (ITO) (which is commonly used because it is transparent)] and the highest occupied orbit (HOMO) of the emissive layer. , Thereby increasing the number of holes introduced into the light emitting layer. In operation, holes are injected into the light emitting layer from the anode and hole injection layer, if present, and electrons are injected from the cathode (cathode) into the light emitting layer. Holes and electrons combine in the light emitting layer to form excitons, which then undergo radiative decay, producing light.

  Some devices also incorporate a thin polymer interlayer between the hole injection layer and the light emitting layer. This plays an important role in improving device efficiency and lifetime of RGB light emitting polymer (LEP) OLEDs. For example, with an interlayer, a blue LEP OLED with an external quantum efficiency greater than 5% (which is 35% higher than without the interlayer) can be obtained. This is considered to be due to suppression of exciton annihilation at the hole injection layer / light emitting layer interface.

  A further important organic electronic device is an organic thin film transistor. Various arrangements of organic thin film transistors are known. An example of such a device is an insulated gate field effect transistor, which includes a source electrode and a drain electrode, a semiconductor material disposed in a channel region therebetween, a gate electrode disposed adjacent to the semiconductor material. And a layer of insulating material disposed between the gate electrode and the semiconductor material in the channel region.

  An example of such an organic thin film transistor is a top-gate thin film transistor, which includes a source electrode and a drain electrode, and both electrodes are separated by a channel region existing therebetween. An organic semiconductor can be deposited in the channel region and can extend to at least a portion of the source and drain electrodes. An insulating layer of dielectric material can be deposited on the organic semiconductor and can extend over at least a portion of the source and drain electrodes. Finally, a gate electrode is formed on the insulating layer. The gate electrode is on the channel region and may extend on at least a portion of the source and drain electrodes.

  The above structure is known as a top gate type organic thin film transistor because the gate exists on the upper surface side of the device. Alternatively, a so-called bottom-gate organic thin film transistor is formed, in which a gate is provided on the bottom side of the device, a gate electrode is formed on the substrate, and an insulating layer of a dielectric material is formed on the top surface. Is also known. The source and drain electrodes are deposited on an insulating layer of dielectric material. The source electrode and the drain electrode are separated by a channel region existing on the gate electrode between the two electrodes. The organic semiconductor may be deposited in the channel region and extend over at least a portion of the source and drain electrodes.

  The conductivity of the channel can be changed by applying a voltage to the gate. In this way, the transistor can be switched on and off using the applied gate voltage. The drain current that can be obtained at a given voltage is dependent on the mobility of charge carriers in the organic semiconductor in the active region of the device (the channel between the source and drain electrodes). Therefore, in order to obtain a high drain current at a low operating voltage, the organic thin film transistor must have an organic semiconductor having highly mobile charge carriers in the channel.

  As in the case of OLEDs, the hole injection layer can be incorporated between the source and drain electrodes and the organic semiconductor layer. This serves to reduce the energy difference between the work function of the electrode and the highest occupied orbit (HOMO) of the organic semiconductor layer, thereby increasing the number of holes introduced into the organic semiconductor layer.

  Another important application of this technology is in the development of white OLED materials and low cost anode structures to enable OLED illumination. This is a very large potential market (estimated to reach $ 6.3 billion by 2018). OLED lighting is an existing technology, especially fluorescent lighting (its lifetime can be shorter than what is advertised, it can contain toxic substances such as mercury, and is practical without an accessory. Becomes an inefficient) and inorganic LED (which is a good point light source but is not well suited for light emitting applications with uniform light scattering over large areas). OLED illumination is well-suited for applications that require light emission with uniform scattering over a large area.

  An important recent development is an OLED that replaces conventional anode materials (such as ITO or gold, both of which are difficult to process and expensive) with photo-patternable precursor metal deposition techniques. Development of lighting tiles (see, for example, WO-A-2004 / 068389). This method of forming a conductive metal region on a substrate includes forming a solution of a metal ion on the substrate, and forming a solution of a reducing agent on the substrate, wherein the metal ion and the reducing agent are in a reaction solution. Forming a film so that a conductive metal region is formed on the substrate by reacting together. By using this method, it is possible to form a metal fine mesh on a substrate in a simple, inexpensive and w liquid phase processable (liquid phase processable) manner.

  For low cost metals such as aluminum and especially copper, very fine mesh tracks on the order of less than 10 microns can be deposited on the substrate, resulting in very high transparency to the anode due to the fineness of the mesh. There is a path to the possibility of making very flexible devices (as opposed to ITO, which is brittle and can crack during processing). ITO also has a high resistivity, which causes problems in large area lighting panels due to, for example, the large voltage drop seen towards the center of the device, resulting in a large reduction in light intensity. Fine metal tracks deposited by the method of WO-A-2004 / 068389 provide a highly conductive surface without the voltage drop that occurs in ITO devices.

  The use of copper and other metals (such as aluminum) in the photo-patternable deposition technique of WO-A-2004 / 068389 has resulted in the replacement of expensive materials such as ITO (and gold if transparency is not important), As well as the disclosed electroless plating technique, both cost is reduced both because it is simpler, cheaper and more efficient than the sputtering technique typically used for ITO. This is particularly important in the development of low cost structures for OLED lighting and organic thin film transistor displays. In either case, metal tracking (eg, copper) is deposited on a transparent substrate (glass) by a liquid phase processable electroless plating technique, and then the remaining layers are further known in the art. The film is formed using a technique capable of liquid phase processing.

  In addition, for maximum efficiency in lighting devices, an outcoupling film to improve emission into the glass compared to conventional ITO devices as a result of reduced guided modes by the glass index matching hole injection layer Is disposed on the bottom surface of the glass substrate. In addition, the use of an outcoupling film to extract light from the glass allows the use of a thicker hole injection layer and improves manufacturing efficiency.

  Other suitable techniques for the deposition of copper and other metals (such as aluminum) include vacuum evaporation, printing, and photolithography.

  However, metal tracking deposited using techniques such as electroless plating techniques, vacuum deposition or photolithography, particularly preferred metals such as copper (which is inexpensive and has good conductivity) and aluminum There are problems with use. First, they are easily oxidized. When an oxide layer is formed on the metal surface, this increases the contact resistance between the metal and the hole injection layer deposited on top of it. This results in a reduction in hole supply from the metal / hole injection layer interface, thus reducing device efficiency. Second, the hole injection layer contains a hydrophilic compound such as PEDT, which is formed from an aqueous solution. As a result, it is not easy to form an aqueous solution of the hole injection compound on the metal surface. Ideally, what is needed is to improve the bonding of the hole injection layer by making the surface hydrophilic. There is a clear need in the art to address such issues.

  A wide variety of corrosion inhibitors are known in the art. Taking copper as an example, copper oxide can be removed from the copper surface by immersion in aqueous acetic acid for 2-3 minutes. However, the oxide immediately begins to reform in the atmosphere. In the case of copper, an example of a widely used copper corrosion inhibitor is cuprotec 3, which contains benzotriazole. Also the use of benzotriazole, and indazole, in some cases to prevent copper corrosion is well known in the art, for example, the use of benzotriazole and indazole is described in J. Am. B. Cotton, I.D. R. Scholes, Br. Corros. J. et al. 2 (1967) 1 is disclosed and tested. Ngoc Huu Huynh (PhD thesis 2004, Queensland University of Technology) discloses the use of some heterocyclic compounds as copper corrosion inhibitors in acidic aqueous environments. In one example, the use of 4-carboxybenzotriazole and 5-carboxybenzotriazole to prevent copper corrosion in corrosive environments is disclosed. The carboxy group was selected under the assumption that it could increase corrosion protection in the target aqueous corrosive environment. There is no disclosure or suggestion that they can be used to control copper corrosion caused by atmospheric corrosion or electromigration effects.

  J. et al. M.M. Park and J.M. P. Bell, Epoxy Adhesion to Copper; Adhesive Aspects of Polymer Coatings. Symposium on Adhesion Aspects of Polymeric Coatings (1981: Minneapolis, 1983, 205-224) improves the water resistance of copper-epoxy bonds by including benzotriazole derivatives, such as 5-hydroxytriazole, between the copper and epoxy layers. Is disclosed. The focus of this disclosure is, for example, improving the resistance of joints formed by copper plates using epoxy resin to water, especially boiling water. The use of additional benzotriazoles and other aromatic derivatives as copper corrosion inhibitors in various devices (such as electronic devices) is described in, for example, US-A-2004 / 0217006, Vishnev'ski, R., et al. Fizika i Kimimiya Tverdogo Tila (2006), 7 (4), 748-750 and US-A-2009 / 0239380. In these and many of the prior art, it is concluded that increased copper corrosion can occur due to the benzotriazole derivatives becoming more hydrophobic. For example, X. R. Ye et al. , Applied Surface Science 135 (1998) 307.

  However, in the prior art, organic electronic devices use compounds that can passivate the metal surface to suppress oxidation of the metal anode and increase the water contact angle so as to increase wettability and are therefore hydrophilic. There is no disclosure or suggestion that allows the compound to be deposited from an aqueous solution onto the top surface (eg, hole injection layer).

International Publication No. 90/13148 Pamphlet International Publication No. 95/06400 Pamphlet WO99 / 48160 pamphlet US Pat. No. 4,539,570 International Publication No. 2004/068389 Pamphlet US Patent Application Publication No. 2004/0217006 US Patent Application Publication No. 2009/0239380

“Organic Light Emitting Materials and Devices”, edited by Zhigang Li and Hong Meng, CRC Press (2007), ISBN 10: 1-57444-574X. J. et al. B. Cotton, I.D. R. Scholes, Br. Corros. J. et al. 2 (1967) 1 Ngoc Huu Huynh (PhD thesis 2004, Queensland University of Technology) J. et al. M.M. Park and J.M. P. Bell, Epoxy Adhesion to Copper; Adhesive Aspects of Polymer Coatings. Symposium on Adhesion Aspects of Polymeric Coatings (1981: Minneapolis, 1983, 205-224) Vishnevs'kii, R .; Fizika i Kimimiya Tverdogo Tila (2006), 7 (4), 748-750 X. R. Ye et al. , Applied Surface Science 135 (1998) 307

  The inventors have described the dual problem of metal tracking as the anode (ie, first, it easily oxidizes and reduces efficiency due to increased contact resistance) with respect to organic electronic devices and methods of making them; In addition, the hole injection layer formed on the anode includes a compound that is a hydrophilic compound such as PEDT-an aqueous solution of a hole injection compound is formed on a metal surface or a conventional corrosion inhibitor. Made a big leap to make it possible to deal with. By using a self-assembled monolayer of molecules having specific characteristics between the metal surface and the hole injection layer, the present invention suppresses oxidation of the metal surface and prevents molecules in the hole injection layer. It has been found that it is possible to obtain the desired hydrophilic surface which ensures that an ideal environment is provided for coating with an aqueous solution.

  Therefore, in the first embodiment of the present invention, an organic electronic device including a metal anode and a hole injection layer, and further a self-assembled monolayer (SAM) between the metal anode and the hole injection layer. And the SAM includes a compound having a portion that can be adsorbed on the surface of the metal anode and a hydrophilic portion.

  As discussed further below, there are many examples of suitable compounds having various moieties that can be absorbed on the surface of the metal anode, and many examples of suitable parts that are hydrophilic. Exists. A key feature of the organic electronic device of the present invention is that it incorporates a SAM having such two parts with essentially two separate functions.

  The portion of the SAM that can be adsorbed on the surface of the metal anode inhibits the oxidation of the metal surface and thus hinders the hole supply through the metal anode / hole injection layer interface in the device of the present invention without the portion. A passivating element that minimizes the contact resistance that would be caused by the presence of a thin film of metal oxide (eg, copper oxide) on the surface.

  The hydrophilic portion is a portion that improves the wettability of the surface and is responsible for changing the contact angle with water compared to the corresponding compound without the hydrophilic group. This improvement in hydrophilicity / wetting results in a hydrophilic surface on the metal, providing an ideal environment for the metal to be coated with an aqueous solution of molecules in the hole injection layer, and optimal A hole injection layer is obtained.

In the second aspect of the present invention, the following steps:
(I) forming a metal anode on the substrate;
(Ii) forming a compound capable of forming SAM on the surface of the metal anode, the compound having a portion capable of being adsorbed on the surface of the metal anode and a hydrophilic portion; And (iii) A method for producing an organic electronic device, comprising a step of forming a hole injection layer on the SAM.

  In a third aspect of the present invention, there is provided a compound capable of forming a SAM for use in passivation of a metal anode of an organic electronic device for inhibiting oxidation of the metal anode, wherein the wettability of the surface of the anode Provided is a compound having a hydrophilic group that improves properties.

  According to a fourth aspect of the present invention, there is provided a compound capable of forming a SAM for use in an organic electronic device comprising a metal anode and a hole injection layer, the SAM comprising the metal anode and the hole injection layer. The SAM having a hydrophilic portion is further reduced in contact resistance between the metal anode and the hole injection layer compared to the same device except that the SAM is not present by including the SAM. Provides compounds that can be formed.

1a and 1b are schematic diagrams of typical OLEDs. FIG. 2 is a schematic diagram of a typical bottom emission OLED according to the present invention. FIG. 3 is a plot of square root (yield) against energy (eV) of a device according to the invention compared to a control device, showing the relative work function. Figures 4a, 4b, 4c, 4d, 4e, 4f and 4g are plots of the square root quantity against the energy (eV) of the device according to the present invention compared to the control device measured at various time points and show the stability. Figures 4a, 4b, 4c, 4d, 4e, 4f and 4g are plots of the square root quantity against the energy (eV) of the device according to the present invention compared to the control device measured at various time points and show the stability. Figures 4a, 4b, 4c, 4d, 4e, 4f and 4g are plots of the square root quantity against the energy (eV) of the device according to the present invention compared to the control device measured at various time points and show the stability. Figures 4a, 4b, 4c, 4d, 4e, 4f and 4g are plots of the square root quantity against the energy (eV) of the device according to the present invention compared to the control device measured at various time points and show the stability. Figures 4a, 4b, 4c, 4d, 4e, 4f and 4g are plots of the square root quantity against the energy (eV) of the device according to the present invention compared to the control device measured at various time points and show the stability. Figures 4a, 4b, 4c, 4d, 4e, 4f and 4g are plots of the square root quantity against the energy (eV) of the device according to the present invention compared to the control device measured at various time points and show the stability. Figures 4a, 4b, 4c, 4d, 4e, 4f and 4g are plots of the square root quantity against the energy (eV) of the device according to the present invention compared to the control device measured at various time points and show the stability. FIGS. 5a and 5b are plots of current density (mA / cm ² ) versus voltage (V) of a device according to the present invention compared to a control device and an enlarged view of a portion thereof. FIGS. 6a and 6b are plots of efficiency (EQE) versus voltage (V) of a device according to the invention compared to a control device and an enlarged view of a portion thereof. FIG. 7 is a plot of current density (mA / cm ² ) versus voltage (V) for the best device. FIG. 8 is a plot of efficiency (EQE) versus voltage (V) for the best device. FIG. 9 is a plot of efficiency (Lm / W) against luminance (Cd / m ² ).

  By incorporating a SAM having the above properties according to the present invention into the organic electronic device of the present invention, a metal anode that is easily oxidized (eg, a metal fine mesh device such as copper or aluminum tracking), ie, positive by oxidation of the metal surface. The hole injection layer results in increased contact resistance (thus hindering the hole supply from the metal / hole injection layer interface) and is coated with an aqueous solution of molecules of the hole injection layer to provide hydrophilic holes It addresses two of the important issues that have limited the efficiency of the device, such as the lack of a hydrophilic surface that ensures that an ideal environment is provided for obtaining a good coating of the injection layer.

  With the device and manufacturing method of the present invention, potentially all (or nearly all) steps in the fabrication of organic electronic devices can be achieved using, for example, liquids, depending on what is used as the cathode material of the OLED device. It is possible to enable phase processing and to easily extend to manufacturing levels (since no vacuum is required for the solution-based deposition technique). The resulting device is relatively inexpensive and has improved efficiency, for example, low contact resistance due to the superior corrosion protection provided by the SAM used in the device of the present invention. Furthermore, the efficiency is also improved by the result of the presence of hydrophilic moieties, such as hydroxy or carboxy groups, on the moieties that can be adsorbed on the surface of the metal anode. When the SAM is adsorbed on the surface of the metal anode, the wettability of the metal surface is greatly improved by the formation of a hole injection layer on the hydrophilic surface from the aqueous solution presented by such groups. It is ensured that an excellent uniform hole injection layer is deposited on the metal surface. This further improves the injection of holes from the hole injection layer by providing an optimal metal-hole injection layer interface.

  Without wishing to be bound by theory, we have changed the contact angle with water by changing the position of the hydrophilic group on the portion that can be adsorbed on the surface of the metal anode. We believe this will result in a change in the surface energy of the bond. This results in a change in the wettability of the SAM molecule when adsorbed on the surface of the metal. This is because when a moiety that can be adsorbed on the surface of the metal anode is adsorbed on the surface of the metal anode, the binding of hydrophilic moieties on the moiety that can be adsorbed on the surface of the metal anode in the SAM compound When the point is present such that the distance of the hydrophilic group from the surface of the metal anode is maximized, an optimal change in surface energy and thus an improvement in the wettability of the surface of the metal anode is obtained. Conceivable.

  In a preferred embodiment of the present invention, the SAM consists of an aromatic compound having a hydrophilic substituent. Preferably, the aromatic compound having a hydrophilic substituent is a benzotriazole derivative, an indazole derivative, a benzimidazole derivative, a benzothiazole derivative or a benzoxazole derivative, more preferably a benzotriazole derivative or an indazole derivative, most preferably a benzotriazole derivative. It is. The aromatic moiety serves as a moiety that can be adsorbed on the surface of the metal anode. In particular, it is considered that nitrogen atoms of the aromatic ring are responsible for adsorption.

  In the SAM compounds present in the devices of the present invention, the hydrophilic substituent is preferably selected from the group consisting of hydroxy, carboxy, carbonyl and thio substituents, which are preferably hydroxyl or carboxy substituents. When SAM is an aromatic compound such as a benzotriazole derivative, the hydrophilic substituent is preferably present at the 4-position or 5-position, more preferably 5-position of the aromatic ring group. The most preferred compounds for use as SAMs in the devices of the present invention are 4-carboxybenzotriazole, 5-carboxybenzotriazole, 5-hydroxybenzotriazole and 4-hydroxybenzotriazole (trizole), most preferably 5-hydroxy Benzotriazole or 5-carboxybenzotriazole.

  In another preferred embodiment of the invention, the SAM consists of a thio compound with a hydrophilic tail. Preferred examples include thioalkane and thioalkene derivatives having 6 to 24 carbon atoms and thioaromatic derivatives having 5 to 14 carbon atoms in one or more aromatic rings. In each case, the derivative is substituted with a hydrophilic group selected from the group consisting of hydroxyl, carboxy and carbonyl. Most preferably, the thio compound having a hydrophilic tail is 11-thio-1-undecanol or 4-thiophenol.

  The organic electronic device of the present invention comprising the SAM discussed above comprises a metal anode. The metal anode of the device of the present invention is typically a metal that is oxidized in the atmosphere at room temperature (typically 25-37 ° C.). This includes most metals to some extent except for the inert metals gold, platinum and palladium. Gold is routinely used in prior art devices to make device anodes where transparency is not important. However, this has various problems. First, clearly this is very expensive. Second, it is difficult to process because it can only be deposited by thermal evaporation techniques. Accordingly, in the devices of the present invention incorporating the SAM discussed above, the metal anode is preferably oxidizing at room temperature (typically 25-37 ° C.) in the atmosphere. More preferably it is a metal selected from the group consisting of copper, aluminum, nickel and silver, more preferably copper. Preferably, the anode is in the form of patterned metal tracking. As discussed further below, this can be deposited by electroless plating techniques (such as those disclosed in WO-A-2004 / 068389). Alternatively, it can also be deposited by vacuum evaporation or photolithography. With these techniques, metal tracking can be deposited, and strict patterning tracking (for example, a very fine mesh) can be produced with tracks on the order of less than 10 microns.

  The hole injection layer preferably contains a conductive material. This assists hole injection from the anode into the light emitting layer. Preferred examples of materials that can be used to form the hole injection layer are those that are highly conductive, particularly those that have a high lateral conductivity so that the current from the anode of the device spreads (this means that the anode Patterned metal tracking, particularly important when in the form of patterned copper metal tracking). Representative examples of materials that can be used to form the hole injection layer include poly (3,4-ethylenedioxythiophene) (PEDT), as well as poly (3,4-ethylenedioxythiophene) -poly. (Styrene sulfonate) (PEDT: PSS) (disclosed in EP 0901176 and EP 0947123 with other doped PEDT); polyaniline (disclosed in US5723873 and US5798170); polypyrrole; polyacrylic acid; and fluorinated sulfonic acids such as Nafion (Registered trademark); optionally substituted polythiophene or poly (thienothiophene), for example, PH510 which is a PEDT: PSS ratio of 1: 2.5 PEDT: PSS commercially available from HeraeusWhen added to 5% DMSO (weight basis) PH510, the conductivity increases to> 300 Scm-1. Preferably, the hole injection layer comprises poly (3,4-ethylenedioxythiophene) (PEDT), poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonate) (PEDT: PSS), polyaniline or polypyrrole. And most preferably comprises PEDT or PEDT: PSS.

  The organic electronic device according to the present invention is an arbitrary one in which a metal anode and a hole injection layer are incorporated, and the inclusion of the SAM according to the present invention increases the corrosion resistance of the metal anode and decreases the contact resistance. As a result of improved wettability of the metal surface and increased device efficiency, deposition of the hole injection layer is improved. Typical examples include organic light emitting diodes (eg, OLED lighting devices), organic thin film transistors, organic photovoltaic devices, organic photosensors, and organic memory array devices.

Preferably, the device, such as an OLED, is:
(I) a metal anode;
(Ii) a SAM comprising a compound having a moiety capable of being adsorbed on the surface of the metal anode and a hydrophilic moiety;
(Iii) a hole injection layer;
(Iv) an organic light emitting layer; and (v) a cathode.

Even more preferably, the device, such as an OLED, is:
(I) substrate;
(Ii) a metal anode on the substrate;
(Iii) a SAM comprising a compound having a portion capable of being adsorbed on the surface of the metal anode and a hydrophilic portion;
(Iv) a hole injection layer on the metal anode;
(V) an organic light emitting layer; and (vi) a cathode is provided on the organic light emitting layer.

  Particularly preferred devices, such as OLEDs, further comprise an intermediate layer and an electron injection layer. Preferably, the intermediate layer is present between the hole injection layer and the light emitting layer and / or between the anode and the hole injection layer. When present, the electron injection layer is present between the cathode and the organic light emitting layer. The preferred OLED of the present invention comprises an intermediate layer between the hole injection layer and the light emitting layer.

  Also, preferred devices of the present invention are encapsulated to avoid moisture and oxygen ingress. Conventional encapsulation techniques can be used.

  The substrate can be any material conventionally used in the art, such as glass or plastic. Preferably, the substrate is transparent. Also preferably, the substrate has good barrier properties to prevent moisture or oxygen from entering the device.

  The metal anode can include any metal having a work function suitable for injecting holes into the emissive layer. If the anode is not required to be transparent (eg, if the cathode is transparent), an opaque conductive material such as opaque metal may be used as the anode. Preferably, the metal is suitable for obtaining low-cost fine mesh tracking (for example, copper or aluminum) by film formation by an electroless plating technique.

  Preferably, the anode is deposited by an electroless plating technique (such as that disclosed in WO-A-2004 / 068389). This technique can enable metal tracking deposition by spin coating or inkjet printers, and can produce precise patterning tracking (eg, very fine meshes) on a 10 micron order track. is there. Alternatively, the anode may be formed by blanket ion sputtering (see, for example, US-A-5,556,520).

  Once the anode is deposited, it is treated to remove all oxides and other materials from the surface of the metal. First, it is washed for about 2 minutes by UV-ozone treatment to remove organic contaminants (if any). The substrate is then immediately immersed in aqueous acetic acid (typically 1-5 M, preferably 2 M acetic acid at a temperature of 50-70 ° C. (preferably 60 ° C.)) or in glacial acetic acid for 1 minute at room temperature. And the oxide is removed from the surface of the anode. This is immediately removed from the acetic acid solution and quickly dried with a nitrogen gun. The dry oxide-free anode deposited on the substrate is then immediately transferred to coating with the next layer of the process (we have a time of up to 2 minutes before the passivation process begins) Found that).

  Preferably, the SAM (examples are shown above) is deposited by liquid phase processing. Any conventional liquid phase processing method can be used. Representative examples of liquid phase processing methods include spin coating, gravure printing, flexographic printing, dip coating, slot die coating, doctor blade coating and ink jet printing. In one example of a preferred method, film formation is by spin coating. From a solution that contacts the metal during the immersion time, a SAM, a self-assembled monolayer, is formed on the metal. The use of a spin coater allows the excess SAM solution to be removed and an effective rinsing mode. Conditions (such as RPM) do not affect the thickness of the SAM. Thus, the substrate can be immersed in an isopropyl alcohol solution of the target SAM after transfer to the spin coater, for example. This is then typically left for 30 seconds to 5 minutes, preferably 1 minute to 3 minutes, most preferably 2 minutes. After the excess SAM solution is removed by rinsing, the substrate is immersed in a solvent and the spinning process is started (typically 500-2000 rpm, preferably 1000 rpm, typically 200-400 rpm / second acceleration). , Preferably 300 rpm / second). Spinning is typically performed for a period of 15 seconds to 1 minute, preferably 30 seconds. At the end of this period, the obtained substrate on which the SAM layer is formed is subjected to dehydration baking (for example, at 70 ° C. for 15 minutes) in a nitrogen glove box.

  Preferably, the hole injection layer (examples are shown above) is deposited on the SAM layer by liquid phase processing. Any conventional liquid phase processing method can be used. Representative examples of liquid phase processing methods include spin coating, gravure printing, flexographic printing, dip coating, slot die coating, doctor blade coating and ink jet printing. In one example of a preferred method, film formation is by spin coating. The parameters used for spin coating of the hole injection layer, such as spin coating speed, acceleration and time, are selected based on the desired layer thickness. After the film formation, the hole injection layer is preferably annealed by heating at 150 to 200 ° C. for 5 to 30 minutes in the air.

  Any compound or combination of compounds suitable for use as a hole injection layer can be used in the devices of the present invention. For example, the PH 510 can be used. Although other representative examples of well-known intermediate layer compounds are discussed above, any compound having properties suitable for use as a hole injection layer may be used.

  The thickness of the hole injection layer is preferably 15 to 200 nm, more preferably 150 nm.

  Intermediate layers that may be present in the devices of the present invention can include any intermediate layer conventionally used for this purpose. Typical examples of the intermediate layer compound include poly (2,7- (9,9-di-n-octylfluorene) -alt- (1,4-phenylene-((4-sec-butylphenyl) imino). ) -1,4-phenylene)) (TFB).

別の例はコポリマー１である。これは、５０％のモノマー１、４２．５％のＦＤＡおよび７．５％の架橋剤ＴＦＢＢＣＢ：

Another example is Copolymer 1. This is 50% monomer 1, 42.5% FDA and 7.5% crosslinker TFBCBB:

を含むコポリマーである。

Is a copolymer comprising

  Preferably, the intermediate layer is formed by a liquid phase treatment method. Any conventional liquid phase processing method can be used. Representative examples of liquid phase processing methods include spin coating, gravure printing, flexographic printing, dip coating, slot die coating, doctor blade coating and ink jet printing such as spin coating. The parameters used for spin coating of the intermediate layer, such as spin coating speed, acceleration and time, are selected based on the desired layer thickness. After film formation, the intermediate layer is preferably crosslinked, for example, by heating at 150 to 200 ° C. for 30 to 120 minutes in a nitrogen glove box.

  The thickness of the intermediate layer is preferably 5 to 50 nm, more preferably 10 to 40 nm, and most preferably 20 to 30 nm.

The organic light emitting layer present in the device of the present invention may comprise any conventional organic light emitting compound and / or organic light emitting polymer. Preferably, the organic light emitting layer includes a light emitting polymer. An example of such an organic light emitting material is Blend 1, which is a blend of Copolymer 2 and Monomer 2. Monomer 2 is a phosphorescent green dopant and is known as fac tris (2-phenylpyridine) iridium or Ir (ppy) ₃ . Similar phosphorescent homoleptic or heteroleptic iridium complexes can be used. The host material for Ir (ppy) 3 can be a phenanthrene or propeller polymer or non-polymer host, or polyfluorene. Suitable organic phosphorescent compounds are described in the book "Organic Light Emitting Materials and Devices" by Zhigan Li and Hong Meng (CRC Press (2007) ISBN 1-57444-574-X 369-375). Chapter 2 of the book describes various light-emitting polymers that may be suitable for use (eg, polyfluorene, PPV, and polythiophene). Copolymer 2 is a copolymer consisting of 25% monomer 1 / monomer 3 (1: 1) and 75% monomer 1 / monomer 4.

有機発光層は、好ましくは、有機発光ポリマーの溶液を正孔注入層上または中間層上に成膜させることにより作製される。任意の慣用的な液相処理法が使用され得る。液相処理法の代表的な例としては、スピンコーティング、グラビア印刷、フレキシ印刷、ディップコーティング、スロットダイコーティング、ドクターブレードコーティングおよびインクジェット印刷が挙げられる。好ましい方法の一例では、成膜はスピンコーティングによるものである。発光層のスピンコーティングに使用されるパラメータ、例えば、スピンコーティング速度、加速および時間は、目的の発光層厚に基づいて選択される。成膜後、有機発光層は、好ましくは窒素グローブボックス内で例えば１００〜１５０℃にて乾燥させる。

The organic light emitting layer is preferably produced by depositing a solution of an organic light emitting polymer on the hole injection layer or the intermediate layer. Any conventional liquid phase processing method can be used. Representative examples of liquid phase processing methods include spin coating, gravure printing, flexographic printing, dip coating, slot die coating, doctor blade coating and ink jet printing. In one example of a preferred method, film formation is by spin coating. The parameters used for the spin coating of the light emitting layer, such as spin coating speed, acceleration and time, are selected based on the desired light emitting layer thickness. After the film formation, the organic light emitting layer is preferably dried at, for example, 100 to 150 ° C. in a nitrogen glove box.

  The thickness of the light emitting layer is preferably 50 to 350 nm, more preferably 75 to 150 nm.

  The electron injection layer that may be present is preferably produced by depositing a solution on the light emitting layer. The method is similar to that of the intermediate layer. The electron injection layer that may be present in the device of the present invention may include any conventional electron injection layer, typically a metal halide (such as LiF or NaF) or preferably an organic compound There may be mentioned a thin layer of an organic compound doped with a salt or a metal ion, which may be deposited from an organic solution (such as lithium phenolate and 4,7-diphenyl-1,10-phenanthroline).

  The cathode is selected from a material having a work function that allows injection of electrons into the light-emitting layer (s). Other factors such as the possibility of deleterious interactions between the cathode and the luminescent material also affect the choice of cathode. The cathode may be made of one type of material such as an aluminum layer. Alternatively, two layers of a plurality of metals, for example, a low work function material and a high work function material (eg, calcium and aluminum (disclosed in WO 98/10621)) may be provided. The cathode may comprise a layer containing barium element (e.g. disclosed in WO 98/57381, Appl. Phys. Lett. 2002, 81 (4), 634 and WO 02/84759). The cathode is a thin (e.g., 1-5 nm thick) layer of a metal compound between the light emitting layer (s) of the OLED and one or more conductive layers (such as one or more metal layers) of the cathode. May be provided. Exemplary metal compounds include oxides or fluorides of alkali or alkaline earth metals (to aid electron injection), such as lithium fluoride (disclosed in WO 00/48258); barium fluoride (Appl. Phys. Lett 2001, 79 (5), 2001); and barium oxide. The cathode preferably has a work function of less than 3.5 eV, more preferably less than 3.2 eV, and most preferably less than 3 eV so as to provide efficient injection of electrons into the device. Metal work functions are described, for example, in Michaelson, J. et al. Appl. Phys. 48 (11), 4729, 1977.

  The cathode may be opaque or transparent. Transparent cathodes are advantageous, especially in active matrix devices, because radiation from the transparent anode of such devices is blocked at least in part by a drive circuit that is present at the bottom of the emitting pixel. A transparent cathode comprises a layer of an electron injecting material that is thin enough to be transparent. Typically, the lateral conductivity of this layer is low as a result of its thinness. In this case, the layer of electron injecting material is used in combination with a thicker layer of transparent conductive material (such as indium tin oxide).

  Transparent cathode devices do not need to have a transparent anode (unless of course a sufficiently transparent device is desired), so that transparent anodes used in bottom emission devices are made of a layer of reflective material. It will be appreciated that (such as an aluminum layer) may be substituted and supplemented. An example of a transparent cathode device is disclosed, for example, in GB 2348316.

  Preferably, there is no electron injection layer and the cathode is a standard sodium fluoride stack (eg, NaF (2 nm) / Al (100 nm) / Ag (100 nm)).

  Suitable encapsulants include glass sheets, films with appropriate barrier properties, such as silicon dioxide, silicon monoxide, silicon nitride or alternating polymer and dielectric laminates (eg disclosed in WO 01/81649) or hermetic containers (For example, disclosed in WO01 / 19142). For transparent cathode devices, a transparent encapsulating layer (such as silicon monoxide or silicon dioxide) can be deposited to a micron level thickness, but in a preferred embodiment the thickness of such layer is in the range of 20-300 nm. .

  In the method according to the second aspect of the invention, the metal anode is preferably pretreated with an agent that removes all metal oxides and organic materials from the surface of the metal anode. First, it is washed for about 2 minutes by UV-ozone treatment to remove organic contaminants (if any). The substrate is then immediately placed in acetic anhydride or an aqueous acetic acid solution (either at a temperature of 30-90 ° C, preferably 1-5M aqueous acetic acid at 60 ° C, preferably 2M aqueous acetic acid or room temperature glacial acetic acid). Immerse for a minute to remove the oxide from the surface of the anode. This is immediately removed from the acetic acid solution and quickly dried with a nitrogen gun. The dry oxide free anode present on the substrate is then immediately transferred to coating with the next layer of the process.

  In a preferred embodiment of the second aspect of the present invention, treatment with an agent that removes all metal oxide from the surface of the metal surface and deposition of a compound capable of forming a SAM on the surface of the metal anode. Are combined into a single liquid phase processing step.

  The inventors believe that in the method of the second aspect of the present invention, the hydrophilic portion of the SAM compound improves the wettability of the SAM compared to the equivalent compound without the hydrophilic group. Further, by including the SAM, the contact resistance between the metal anode and the hole injection layer is reduced compared to the same device except that the SAM is not present.

  In a preferred embodiment of the second aspect of the second invention, the metal anode is deposited, sputtered (eg, Leybold® blanket sputtering (eg, described in US-A-5,556,520)) and no A method is provided that is in the form of a patterned metal tracking that is deposited on a substrate by a process selected from the group consisting of electroplating, preferably electroless plating. The electroless plating technique is particularly preferably an electroless plating technique such as that disclosed in WO-A-2004 / 068389. In its most basic form, it forms a solution of the metal ion solution on the substrate, and the metal ion and the reducing agent react together in the reaction solution to form a conductive metal region on the substrate. Forming a solution of the reducing agent on the substrate such that a conductive metal region is formed on the substrate. The reaction between the metal ion and the reducing agent is typically activated by an activator (such as a second conductive metal different from the first). When used, the activator is typically first deposited on a substrate to obtain a patterned structure. Next, a first metal ion and a reducing agent are further formed on the substrate to obtain a desired anode as a metal tracking having a desired pattern.

A preferred method according to the invention comprises the following steps:
(I) Preferably a step of forming a copper patterned metal tracking on a glass substrate by electroless plating, preferably forming a solution of the metal ions on the glass substrate, The pattern forming metal tracking is formed by forming a solution of a reducing agent on the substrate so that the metal ions and the reducing agent react together in the reaction solution to form a conductive metal region on the substrate. Forming a step;
(Ii) treating the patterned metal tracking with 1-5 M acetic acid solution to remove all oxides from the surface of the metal and immediately drying;
(Iii) A step of forming a compound capable of forming SAM from a solution on the surface of the patterned metal tracking prepared in step (ii), wherein the compound capable of forming SAM is the patterned metal tracking. Having a portion that can be adsorbed on the surface of the substrate and further having a hydrophilic portion, and the film formation is preferably selected from the group consisting of spin coating, dip coating, slot die coating, doctor blade coating, and inkjet printing. Performed by the process
(Iv) A hole injection layer from solution is applied onto the SAM made in step (iii), preferably by a process selected from the group consisting of spin coating, dip coating, slot die coating, doctor blade coating and ink jet printing. Forming a film;
(V) forming an intermediate layer from the solution on the hole injection layer prepared in step (iv) by a process selected from the group consisting of spin coating, dip coating, slot die coating, doctor blade coating, and inkjet printing; An optional step;
(Vi) Spin coating, dip coating, slot die coating, doctor blade coating and ink jet printing on the organic light emitting layer from the solution on the hole injection layer prepared in step (iii) or the intermediate layer prepared in step (v) Forming a film by a process selected from the group consisting of: and (vii) thermal evaporation of a metal, metal oxide or metal halide on the organic light emitting layer produced in step (vi), preferably NaF / Al / Ag cathode is formed on the organic light emitting layer.

  A cross section of the basic structure of a typical OLED 1 is shown in FIG. A glass or plastic substrate 2 supports, for example, a transparent anode layer 4 with a metal (eg copper or aluminum) anode in the form of a patterned metal tracking having a mesh on the order of less than 10 microns, on which The hole injection layer 6, the intermediate layer 8, the organic light emitting layer 10 and the cathode 12 are formed. The hole injection layer 6 assists in matching the hole energy levels of the anode layer 4 and the light emitting layer 10 and includes a conductive transparent polymer. The cathode 12 includes, for example, three layers of sodium fluoride, aluminum, and silver. Contact wires 14 and 16 to the anode and cathode each provide a connection to a power source 18.

  In so-called “bottom emission” devices, a multilayer sandwich is deposited on the front side of a flat glass substrate, and the reflective electrode layer (usually the cathode) is furthest from the substrate, so that the light generated inside the light-emitting layer is Bond out of the device, out of the device. An example of the bottom emission type 1a is shown in FIG. 1a. In the figure, light 20 is emitted from the transparent anode 4 and the substrate 2, and the cathode 12 is reflective.

  In contrast, in the so-called “top emission type”, the multilayer sandwich is disposed on the back surface of the substrate 2, and the light generated inside the light emitting layer 10 is coupled outside from the transparent electrode layer 12 without passing through the substrate 2. . An example of the top emission type 1b is shown in FIG. 1b. Usually, the transparent electrode layer 12 is a cathode, but devices emanating from the anode can also be constructed. The cathode layer 12 can be made substantially transparent, for example, by maintaining the thickness of the cathode layer below approximately 50-100 nm.

  A cross section of a bottom emission device according to the present invention is shown in FIG. A glass or plastic substrate 2 supports a transparent anode layer 4 with a metal (eg, copper) anode in the form of a patterned metal tracking with a thickness on the order of 100 nm. This can be deposited, for example, by electroless plating techniques (such as those disclosed in WO-A-2004 / 068389) or blanket ion sputtering (eg, Leybold® blanket sputtering). On the metal tracking 4, a compound having a portion that can be adsorbed on the surface of the metal anode and a hydrophilic portion, for example, a hydrophilic benzotriazole derivative (such as 5-hydroxybenzotriazole or 5-carboxybenzotriazole) is formed. A SAM 22 is formed. A hole injection layer 6 is formed on the SAM. Next, the intermediate layer 8, the organic light emitting layer 10 and the cathode 12 are continuously formed. The hole injection layer 6 assists in matching the hole energy levels of the anode layer 4 and the light emitting layer 10 and includes a conductive transparent polymer. The cathode 12 comprises, for example, a trilayer of silver, aluminum and sodium fluoride. Contact wires 14 and 16 to the anode and cathode each provide a connection to a power source 18.

  The present invention may be further understood by considering the following examples.

Preparation of various SAM treated substrates and measurement of water contact angle of the resulting treated substrate (a) A 2 inch (5.08 cm) 100 nm copper substrate was prepared by Leybold® blanket sputtering. . The resulting substrate having a copper anode deposited on top was then prepared for deposition from a molecular solution selected for use as a SAM. The method is as follows.

  (B) A SAM ink preparation was prepared. To do this, a 10 ml vial was washed with tetrahydrofuran and dried by blowing with a nitrogen gun. In the 10 ml vial, a desired amount of SAM substance to be tested was weighed in a glove box with an inert nitrogen atmosphere. An appropriate amount of the desired solvent (isopropyl alcohol in this test) was added to the same 10 ml vial in this glove box under the same conditions. The mixture was then vortexed for 1-2 minutes and then placed in a heating block for 1 hour or completely until dissolved.

  (C) An acetic acid solution bath was also prepared. This used a 0.45 μm PVDF (polyvinylidene fluoride) filter, with filtration of up to 200 ml of 2M acetic acid into a beaker. The beaker was then heated to 60 ° C. Prior to use, the temperature of the solution was allowed to stabilize for at least 20-30 minutes.

(D) Pretreatment of 2 inch panel The 2 inch (5.08 cm) substrate prepared in the above step (a) was washed with UV treatment for 120 seconds to remove organic contaminants (if any). The substrate was then placed in a 2M acetic acid beaker prepared in step (c) above for 1 to 3 minutes to remove any oxide from the metal surface. The substrate was then extracted and immediately dried with a nitrogen blow gun (no water rinse).

(E) SAM Treatment of 2 Inch Pretreatment Panel A 2 inch (5.08 cm) pretreated substrate was immediately transferred to a Karl-Suss spin coater for SAM treatment. This pretreated substrate was immersed in the SAM prepared in step (b) above, which had been filtered using a 0.45 μm PTFE (polytetrafluoroethylene) filter, and then left for 2 minutes. did. The substrate was then rinsed with 10 ml isopropyl alcohol (which had been filtered using 0.45 μm PTFE). For this purpose, the substrate was first immersed in 2 ml of isopropyl alcohol. The substrate was then spun at 1000 rpm / 300 rpms / 60 seconds and an additional 8 ml of solvent was added during spinning. At the end of this time, the obtained substrate with the SAM film formed on the upper surface was subjected to dehydration baking in a nitrogen gun at 70 ° C. for 15 minutes.

  A series of experiments were performed to measure the water contact angle of untreated copper (with or without ozone treatment) and compared to the water contact angle when the copper surface was treated with various compounds such as: did.

結果を表１にまとめる。

The results are summarized in Table 1.

このように、銅表面を処理するために使用した化合物の性質、特に、芳香族基上の置換基の親水性に応じて水接触角の変化がみられることがわかる。水接触角の改変により金属の表面エネルギーが改変される。これにより、金属表面上に吸着され得る部分の結合の改善がもたらされ、親水性の改善ならびにぬれ性の増大がもたらされる。ＣＢＴＡ（３０°）、ＨＢＴ（３１°）およびＨＵＴ（３２°）では、ＵＶオゾン対照（３１°）と比較した場合、許容範囲の水接触角が得られる。このようなＳＡＭは親水性の尾を有する。非ＳＡＭ処理銅（ここでは対照）の良好なぬれ性は、酸化銅層（これは電子的性能に有害である）を有するためであるが、非酸化銅では不充分なぬれ性しか得られない。未処理銅のぬれは充分であるが、上面に酸化物層を有し、これは不充分なデバイス性能をもたらす。銅は、その酸化物を除去すると該酸化物が再形成されるまで良好なぬれを示さず、したがって、銅を、水に対して良好な接触角をもたらすＳＡＭで保護する必要がある。

Thus, it can be seen that the water contact angle changes depending on the properties of the compound used to treat the copper surface, particularly the hydrophilicity of the substituent on the aromatic group. Modification of the water contact angle modifies the surface energy of the metal. This results in improved binding of the moieties that can be adsorbed on the metal surface, resulting in improved hydrophilicity as well as increased wettability. CBTA (30 °), HBT (31 °) and HUT (32 °) give acceptable water contact angles when compared to the UV ozone control (31 °). Such SAMs have a hydrophilic tail. The good wettability of the non-SAM treated copper (in this case the control) is due to having a copper oxide layer (which is detrimental to electronic performance), but the non-copper oxide provides poor wettability. . The wetness of the untreated copper is sufficient, but has an oxide layer on the top surface, which results in poor device performance. Copper does not show good wetting until the oxide is re-formed when the oxide is removed, and therefore the copper needs to be protected with a SAM that provides a good contact angle to water.

  Further, it is considered that the surface energy changes due to the change of the position of the hydrophilic group. This causes the wettability of the compound when bonded to a copper patterned substrate, thus providing the potential for maximum wettability. According to the calculations of the present inventors, the maximization of the wettability is determined by the fact that the hydrophilic group is on the SAM molecule and the adsorption part of the SAM molecule on the surface is actually adsorbed on the surface of the metal. It has been shown that it can be achieved by coupling to exist at a maximum distance from the surface. 5-hydroxybenzotriazole and 5-carboxytriazole are two examples. This concept applies to any type of group that can provide hydrophilicity when attached to any position on the benzene ring, where the compound can also be adsorbed to the surface of the metal anode to form a SAM. obtain.

  In the next second experiment, the contact angle with SCA126-2 (PEDT) was measured. The results are as shown in Table 2.

この場合も、ＣＢＴＡ（３８°）、ＨＢＴ（３５°）およびＨＵＴ（３２°）では、ＵＶオゾンなし対照（４０°）と比較した場合、許容範囲の接触角が得られる。

Again, CBTA (38 °), HBT (35 °) and HUT (32 °) give acceptable contact angles when compared to the UV ozone-free control (40 °).

Comparison of Work Function and Stability of SAM Treated Substrates (a) To measure the photoelectron spectrum at AC-2 of the substrate prepared in Example 1, ie, the square root of the photoelectron amount relative to the incident photon energy (eV) ( This was tested to examine the plot (which is directly proportional to the number of photoelectrons counted). This provides a measure of the work function of SAM-treated copper relative to that of untreated copper. The measurement was performed for 1 minute after completion of the SAM treatment. As can be seen from FIG. 3, the AC-2 response on copper substrates treated with F4TCNQ, HOTBA, CBTA, HBT and HUT shows a higher work function compared to untreated copper. In contrast, both AC-2 responses with MBI and MBT show a lower work function compared to untreated copper.

  (B) The same procedure as in (a) above was followed, but this time measurements were taken at several times after the preparation of the SAM-treated copper to examine the stability of the substrate. Specifically, the measurement was performed after 1 minute, 10 minutes, and 3 hours. Figures 4a, 4b, 4c, 4d, 4e, 4f and 4g show excellent stability over a 3 hour test period for copper substrates treated with HOTBA, CBTA, HBT and HUT, but F4TCNQ, MBI and All MBTs show inadequate stability and it can be seen that their work function is moving towards that of untreated copper over a period of 3 hours. For example, when the copper surface is treated with CBTA, the plot of the square root amount versus energy shows a shift away in the direction of higher energy (above about 5.2 eV) compared to untreated copper. This confirms that there is a clear difference on the copper surface as a result of CBTA binding, i.e. stable CBTA binding.

Fabrication of OLEDs containing CBTA SAMs OLED devices with the following were fabricated:
The substrate is glass obtained from Corning.

  The anode is a 100 nm thick copper anode formed on a substrate by the blanket sputtering method described in Example 1. Copper was patterned in a metal grid by photo-patterning techniques.

  The prepared substrate was washed for 120 seconds using UV treatment to remove organic contaminants (if any). The substrate was then placed in a prepared 60 ° C. 2M acetic acid beaker for 1 minute to remove any oxide from the metal surface. The substrate was then extracted and immediately dried with a nitrogen blow gun (no water rinse).

  The SAM, when present, is 5-carboxybenzotriazole (also known as benzotriazole-5-carboxylic acid) and is deposited on a copper anode by spin coating to form the SAM layer described in Example 1. obtain. In a “short time SAM” device, the substrate is subjected to a 1 minute SAM process, whereas in a “long time SAM” device, the substrate is subjected to a 3 minute SAM process. As a control, isopropyl alcohol alone was included in the spinner to make a further device without 5-carboxybenzotriazole ("IPA rinse" device). This control is whether the observed benefit (if any) is due to SAM alone Or if the benefit (if any) is due to rinsing with a solvent (in the case of an “IPA rinsing” device, rinsing with solvent but no SAM molecules present).

  The hole injection material is PH510, a PEDT: PSS ratio of 1: 2.5 PEDT: PSS commercially available from Heraeus. 5% DMSO (by weight) is added to PH510 to increase the conductivity to> 300 Scm-1.

  The interlayer material is Copolymer 1 (compolymer comprising 50% monomer 1, 42.5% FDA monomer and 7.5% crosslinker TFBBCB-see above). The electroluminescent layer is a blend, ie a blend of copolymer 2 and monomer 2 (see above). The cathode is NaF (2 nm) / Al (100 nm) / Ag (100 nm).

  The hole injection layer was formed by spin coating from a solution using a Karl-Suss spin coater (spin speed of 1500 rpm for 60 seconds in the atmosphere). This was then dried in air at 130 ° C. for 15 minutes. The resulting hole injection layer was 150 nm thick.

A copolymer 1 intermediate layer (see above) was then deposited on the hole injection layer deposited on each test device in the previous step using a Karl-Suss spin coater from a xylene solution (within the glove box). Spin rate 150 rpm for 6 seconds; then X-bond in an N ₂ glove box at 180 ° C. for 60 minutes and dry the interlayer). The resulting Copolymer 1 interlayer was 22 nm thick.

  After each interlayer was deposited on each test device, the electroluminescent layer, which was a blend of copolymer 2 and monomer 2 (see above), was then transferred from the xylene solution using a Karl-Suss spin coater. A film was formed on the intermediate layer formed on each test device in the process (7 seconds at a spin speed of 1500 rpm in the glove box, and then baked at 130 ° C. for 10 minutes in the glove box). The resulting copolymer 2: monomer 2 blend electroluminescent layer was 100 nm thick.

  Finally, after depositing an electroluminescent layer on each intermediate layer of each test device, each test device was subjected to sodium fluoride (2 nm), aluminum (100 nm) and silver (100 nm) by continuous thermal evaporation in vacuum. ) Was formed into a blanket film to obtain a three-layer NaF / Al / Ag cathode.

  Details of the test devices made according to the above procedure are as shown in Table 3 below:

上記で作製したデバイスの電圧（Ｖ）に対する電流密度（ｍＡ／ｃｍ^２）のプロットおよびその一部分の拡大図を示す図５ａおよび５ｂにより以下のことが示された：
・イソプロピルアルコールすすぎ洗浄により対照デバイスと同一の電流密度が得られた−イソプロピルアルコール処理はデバイス性能に影響しなかった、したがって、イソプロピルアルコールすすぎ洗浄は漏洩電流の低減を担わないことを示す。

Figures 5a and 5b showing a plot of current density (mA / cm ² ) versus voltage (V) of the device fabricated above and an enlarged view of a portion thereof show the following:
• Isopropyl alcohol rinse gave the same current density as the control device—Isopropyl alcohol treatment did not affect device performance, thus indicating that isopropyl alcohol rinse does not contribute to reducing leakage current.

  -Inclusion of the SAM layer increased the current density of the device with the copper anode to near the current density level obtained with the gold anode.

  -There seemed to be almost no difference between short-time SAM processing and long-time SAM processing.

The best device measurements (see FIGS. 7-9) show that:
SAM split confirms that the current density of the copper anode is increased to a level close to that obtained with the control gold anode anode.

  Furthermore, it is confirmed that there is almost no difference between the short-time SAM process and the long-time SAM process.

  The isopropyl alcohol rinse wash split gave the same current density as the copper control split. Thus, it is confirmed that the increase in current density seen with SAM-treated copper is not simply due to further processing of the substrate, but is actually due to SAM.

Device data at 1000 Cd / m ² for the devices produced in these experiments is as shown in Table 4 below:

・ＳＡＭスプリットにより、銅アノードの効率が金アノードで得られるレベル近くまで高まる。

• The SAM split increases the efficiency of the copper anode to a level close to that obtained with a gold anode.

  There seems to be little difference between short-time SAM processing and long-time SAM processing.

  The isopropyl alcohol rinse wash split provides similar efficiency to the copper control split—ie, the increased efficiency seen with SAM-treated copper is not simply due to further processing of the substrate, but is actually due to the SAM.

  Thus, from the above table, the performance of the device according to the invention including 5-carboxytriazole (whether short or long treatment) is significantly better than the copper control device (and isopropyl alcohol control device). I understand that. Furthermore, it can be seen that the performance (especially for short time processing) is quite close to that of the gold control device. This shows strong evidence that including a SAM layer actually has the desired dual effect of reducing contact resistance and increasing wettability.

Claims (20)

An organic electronic device comprising a metal anode and a hole injection layer, further comprising a self-assembled monolayer (SAM) between the metal anode and the hole injection layer, wherein the SAM comprises the metal look containing a compound having an anode portion may be adsorbed on the surface and a hydrophilic portion, said hydrophilic portion of the compound of the SAM is improved compared with the same compound without the hydrophilic group wettability of SAM, Organic electronic devices.   The point of attachment of the hydrophilic moiety on the portion that can be adsorbed on the surface of the metal anode in the SAM compound is the distance of the hydrophilic group from the surface of the metal anode is on the surface of the metal anode. The organic electronic device of claim 1, wherein the portion that can be adsorbed is maximized when adsorbed on the surface of the metal anode. The inclusion of the SAM, the contact resistance of the metal and the hole injection layers, except that the SAM is not present is reduced as compared with the same device, an organic electronic device according to claim 1 or 2. The organic electronic device according to any one of claims 1 to 3 , wherein the SAM is made of an aromatic compound having a hydrophilic substituent. The organic electronic device according to claim 4 , wherein the aromatic compound having a hydrophilic substituent is a benzotriazole derivative or an indazole derivative. Wherein the hydrophilic substituent is hydroxy, carboxy, selected from the group consisting of carbonyl and thio substituents, organic electronic device according to any one of claims 1-5. The organic electronic device according to claim 5 or 6 , wherein the hydrophilic substituent is present at the 4-position or 5-position of the aromatic ring group of the benzotriazole derivative or indazole derivative . The SAM is from a benzotriazole derivative selected from the group consisting of 4-hydroxy-1-benzotriazole, 5-hydroxy-1-benzotriazole, 4-carboxy-1-benzotriazole and 5-carboxy-1-benzotriazole; The organic electronic device according to any one of claims 4 to 7 . The SAM comprises a thioalkane or thioalkene derivative having 6 to 24 carbon atoms or a thioaromatic derivative having 5 to 14 carbon atoms in one or more aromatic rings, wherein the thioalkane, thioalkene and thioaromatic The organic electronic device according to any one of claims 1 to 3 , wherein the derivative is substituted with a hydrophilic group selected from the group consisting of hydroxyl, carboxy and carbonyl. It said metal anode metal is copper, aluminum, nickel or silver, an organic electronic device according to any one of claims 1-9. Metal anode is in the form of a patterned metal layer, an organic electronic device according to any one of claims 1-10. The hole injection layer is made of poly (3,4-ethylenedioxythiophene) (PEDT), poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonate) (PEDT: PSS), polyaniline, PEDT: PSS. ratio 1: 2.5 PEDT: PSS or Poripiro comprising at least one compound le or we selected, the organic electronic device according to any one of claims 1 to 11. The following steps:
(I) forming a metal anode on the substrate;
A step of forming a compound capable of forming a SAM on (ii) the metal anode surface, the compound possess a portion and a hydrophilic moiety which can be adsorbed on the metal anode surface, the A method in which the SAM comprises a benzotriazole derivative or an indazole derivative ; and (iii) forming a hole injection layer on the SAM. 14. The method of claim 13 , wherein the metal anode is pretreated with an agent that removes all metal oxide from the surface of the metal anode. The method of claim 14 , wherein the metal anode is pretreated with acetic anhydride or an aqueous acetic acid solution. 14. The method of claim 13 , wherein the inclusion of the SAM reduces the contact resistance between the metal anode and the hole injection layer compared to the same device except that the SAM is not present. 14. The method of claim 13 , wherein the SAM has a hydrophilic substituent selected from the group consisting of hydroxy, carboxy, carbonyl and thio substituents. The method according to claim 17 , wherein the substituent is present at the 4-position or 5-position of the aromatic ring group of the benzotriazole derivative or indazole derivative . The hole injection layer comprises poly (3,4-ethylenedioxythiophene) (PEDT), poly (3,4-ethylenedioxythiophene) - poly (styrene sulfonate) (PEDT: PSS), polyaniline or Poripiro Le The method according to any one of claims 13 to 18 , comprising. The following steps:
(I) patterning a metal layer comprising the steps of forming a film by electroless plating on a glass substrate, a solution of a reducing agent prior Symbol glass substrate, the metal ions and the reducing agent together in the reaction solution Forming the patterned metal layer by forming a film so that a conductive metal region is formed on the substrate by reaction;
(Ii) treating the patterned metal layer with 1-5M acetic acid solution to remove all oxides from the surface of the metal and immediately drying;
(Iii) forming a SAM-forming compound from a solution on the surface of the pattern-forming metal layer prepared in step (ii), wherein the SAM-forming compound is the pattern-forming metal layer Having a portion that can be adsorbed on the surface of the substrate and further having a hydrophilic portion, wherein the film formation is performed by a process selected from the group consisting of spin coating, dip coating, slot die coating, doctor blade coating, and inkjet printing. Performed, steps;
(Iv) forming a hole injection layer from the solution on the SAM prepared in step (iii) by a process selected from the group consisting of spin coating, dip coating, slot die coating, doctor blade coating, and inkjet printing; ;
(V) forming an intermediate layer from the solution on the hole injection layer prepared in step (iv) by a process selected from the group consisting of spin coating, dip coating, slot die coating, doctor blade coating, and inkjet printing; An optional step;
(Vi) Spin coating, dip coating, slot die coating, doctor blade coating and ink jet printing on the organic light emitting layer from the solution on the hole injection layer prepared in step (iii) or the intermediate layer prepared in step (v) step deposited by a process selected from the group consisting of; and (vii) a cathode in the organic light-emitting layer prepared in the step (vi) comprises a film to process claims for the production of organic light emitting diodes The method according to any one of 13 to 19 .

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