Charge transport thin films

Abstract

To provide an ink composition that provides a charge transporting thin film of uniform thickness without excessively deteriorating the characteristics of an organic EL device.SOLUTION: An ink composition includes (a) a charge transporting substance, (b) one or more metal oxide nanoparticles, and (c) a liquid carrier including (c-1) a first hydrophilic glycol-based solvent having a boiling point bp1 (°C), (c-2) a second hydrophilic glycol-based solvent having a boiling point bp2 (°C), and (c-3) an organic solvent having a boiling point bp3 (°C), and in which bp1<bp3<bp2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an ink composition comprising a charge transport material, metal oxide nanoparticles, and a liquid carrier having a predetermined composition. [Background technology]

[0002] While there have been useful advances in energy-efficient devices, such as organic-based organic light-emitting diodes (OLEDs), polymer light-emitting diodes (PLEDs), phosphorescent organic light-emitting diodes (PHOLEDs), and organic photovoltaic devices (OPVs), further improvements are still needed to provide better material processing and / or device performance for commercialization. For example, one promising type of material used in organic electronics is conductive polymers, including polythiophenes. However, problems can arise due to the purity, processability, and instability of polymers in their neutral and / or conductive states. Furthermore, it is important to have excellent control over the solubility of polymers used in alternating layers of various device architectures (e.g., orthogonal or alternating solubility properties between adjacent layers in a particular device architecture). For example, these layers, also known as hole-injection layers (HILs) and hole-transport layers (HTLs), can pose challenging challenges given the competing requirements and the need for very thin, yet high-quality, films.

[0003] In a typical OLED device stack, the refractive index of most p-doped polymer HILs, such as HILs containing PEDOT:PSS, is around 1.5, while the emissive material generally has a much higher refractive index (1.7 or greater). As a result, additive total internal reflection occurs at the EML / HIL (or HTL / HIL) and HIL / ITO interfaces, resulting in reduced light extraction efficiency.

[0004] There is an unmet need for good platform systems to control the properties of hole injection and hole transport layers, such as solubility, thermal / chemical stability, and electronic energy levels (e.g., HOMO and LUMO), so that these compounds can be tailored for different applications and to function with different compounds, such as light-emitting layers, photoactive layers, and electrodes. Good solubility, solvent intractability, and thermal stability are important properties. Also important is the ability to tune the resistance of the HIL and the thickness of the HIL layer while maintaining high transparency, low absorption, low internal reflection, low operating voltage in OLED systems, and longer lifetime, among other properties. It is also important to be able to tailor a system for a specific application and provide the required balance of these properties.

[0005] One known method for forming charge-transporting thin films for organic EL devices, including HIL and HIL, using the above-mentioned conductive polymers is to apply an ink composition consisting mainly of a liquid carrier in which a conductive polymer is dispersed or dissolved onto a substrate (in many cases, more precisely, onto a thin-film electrode formed on the substrate) to form a coating film, and then dry the resulting coating film to remove the liquid carrier, thereby forming a charge-transporting thin film. Because organic EL devices deteriorate when exposed to moisture, this ink composition is preferably non-aqueous. Furthermore, non-aqueous ink compositions with various compositions have been proposed for the purpose of improving various properties of charge-transporting thin films and organic EL devices using them.

[0006] Patent Document 1 discloses an ink composition to which an amine compound is added. The presence of the amine compound in the ink composition not only provides the ink composition with good shelf life and stability, but also a thin film formed from the ink composition exhibits excellent uniformity, and an OLED device including an HIL formed from the ink composition exhibits good performance.

[0007] Patent Documents 2 and 3 disclose ink compositions containing metal and / or semimetal nanoparticles. These nanoparticles are useful for improving the properties of organic EL devices, such as brightness, thermal stability, and hole injection, and for reducing variations in properties between products.

[0008] Various methods for applying such ink compositions are known. One example of such a method is the inkjet method (droplet ejection method), in which the ink composition is ejected as minute droplets from a nozzle and deposited on a substrate. When a charge-transporting thin film is formed on a substrate using the inkjet method for the purpose of manufacturing an organic EL device, a method is often adopted in which a bank (partition wall) is formed on a thin-film electrode (in many cases, a patterned thin-film electrode) formed on the substrate, a required region on the thin-film electrode is made to be a film-forming region surrounded by the bank, and the ink composition is applied by the inkjet method only to the film-forming region to form the charge-transporting thin film.

[0009] The charge-transporting thin film formed as described above preferably has a uniform thickness throughout the entire thin film. However, in reality, particularly when formed by a method using a bank as described above, the charge-transporting thin film may have a non-uniform thickness. One example of such a state is a state in which the thickness of the peripheral portion of the formed charge-transporting thin film increases in a direction from the center to the edge of the thin film. This occurs because the ink composition applied within the film-forming region creeps up the side of the bank, causing the thickness of the periphery of the formed coating film to increase in a direction from the center to the edge of the coating film (in other words, the portion where the coating film contacts the side of the bank). As a result, the charge-transporting thin film formed from the coating film in this state has a non-uniform thickness, as described above. In this specification, the phenomenon in which the ink composition creeps up the side of the bank is referred to as the "pile-up phenomenon" or simply "pile-up."

[0010] To prevent the applied ink composition from adhering to the side surfaces of the banks and to form a coating of uniform thickness in the film formation region, the side surfaces of the banks that come into contact with the ink composition (coating) are often subjected to a treatment (e.g., a predetermined plasma treatment) to make them liquid-repellent to the ink composition, and the surface of the substrate (thin film electrode) that will become the film formation region is also often subjected to a treatment (e.g., another predetermined plasma treatment) to make it liquid-philic to the ink composition. In this specification, a substrate that has been subjected to such a treatment is referred to as a "substrate with liquid-repellent banks." However, even when a substrate with liquid-repellent banks is used, the pile-up phenomenon may not be sufficiently suppressed.

[0011] As described above, various additional components are often added to ink compositions for the purpose of improving various properties of charge-transporting thin films and organic EL devices using the same, but depending on the added components, pile-up may be induced. In fact, as will be described later, the present inventors have found that, under certain conditions, the addition of metal oxide nanoparticles to an ink composition significantly increases the occurrence of the pile-up phenomenon.

[0012] The uneven thickness of the charge-transporting thin film caused by the pile-up phenomenon may cause electrical defects (such as leakage current and short circuits) through the thickened portion of the thin film, which may shorten the life of the organic EL device. Furthermore, the uneven thickness of the charge-transporting thin film may also cause uneven thickness in the adjacent light-emitting layer, which, combined with the electrical defects, may cause uneven light emission from the organic EL device.

[0013] As a means for suppressing the pile-up phenomenon, for example, it has been proposed to appropriately adjust the composition of the liquid carrier of the ink composition (see Patent Documents 4 and 5). However, the ink composition in this case consists only of the liquid carrier and the conductive substance, and is not intended to suppress the pile-up phenomenon in an ink composition to which additional components have been added as described above.

[0014] That is, there has been no known means for suppressing the pile-up phenomenon in ink compositions containing additional components for the purpose of improving the characteristics of charge transport thin films or organic EL devices. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] International Publication No. 2016 / 171935 [Patent Document 2] International Publication No. 2017 / 014945 [Patent Document 3] International Publication No. 2017 / 014946 [Patent Document 4] International Publication No. 2016 / 140205 [Patent Document 5] Patent Publication No. 2015-185640 Summary of the Invention [Problem to be solved by the invention]

[0016] Under these circumstances, the present inventors have conducted extensive research to develop a means for suppressing the pile-up phenomenon in ink compositions containing the above-mentioned additional components. As a result, the present inventors have unexpectedly found that in ink compositions containing a combination of a charge transporting substance and a liquid carrier to which metal oxide nanoparticles are added, there is a correlation between the dispersion state of the metal oxide nanoparticles in the composition and the occurrence of the pile-up phenomenon, and that the more uniform the dispersion state, the more pronounced the occurrence of the pile-up phenomenon tends to be.

[0017] The inventors have also discovered that the dispersion state of metal oxide nanoparticles in the ink composition is affected by the solvent used, particularly the composition of the organic solvent, and that by specifying the composition of the organic solvent, this dispersion state can be appropriately controlled, particularly during the process of volatilizing the solvent, making it possible to suppress the pile-up phenomenon.

[0018] The present inventors further discovered that, when an organic solvent having the above-mentioned specific composition is not used as a liquid carrier, even if the pile-up phenomenon is suppressed, certain characteristics of the resulting organic EL device, such as current efficiency, tend to decrease, whereas when an organic solvent having the above-mentioned specific composition is used as a liquid carrier, the characteristics of the organic EL device are unexpectedly not excessively decreased. Based on the above new findings, the present invention has been completed.

[0019] Therefore, a main object of the present invention is to provide an ink composition that can provide a charge-transporting thin film of uniform thickness without excessively deteriorating the properties of an organic EL device. These and other objects, features, and advantages of the present invention will become apparent from the following detailed description and claims, taken in conjunction with the accompanying drawings.

[0020] That is, the present invention provides the following inventions.

[0021] 1. An ink composition comprising: (a) Charge transporting substance; (b) one or more metal oxide nanoparticles; and (c) a liquid carrier, (c-1) Boiling point bp 1 a first hydrophilic glycol-based solvent having a viscosity of (°C); (c-2) Boiling point bp 2 a second hydrophilic glycol-based solvent having a temperature of (°C), and (c-3) Boiling point bp 3 (°C) Including, bp 1 <bp 3 <bp 2 a liquid carrier An ink composition comprising:

[0022] 2. The ink composition according to item 1 above, wherein the solvent (c-3) is a hydrophobic glycol solvent, a nitrile, an alcohol, an aromatic ether, an aromatic ester, or an aromatic hydrocarbon.

[0023] 3. The ink composition according to item 1 or 2 above, wherein the solvent (c-3) is a hydrophobic glycol solvent.

[0024] 4. The ink composition according to any one of items 1 to 3 above, wherein the solvents (c-1) and (c-2) are both glycol solvents, and the solvent (c-3) is a glycol diether solvent.

[0025] 5.bp 1 is 180°C or higher, and bp 2 is 270°C or higher, and bp 3 5. The ink composition according to any one of items 1 to 4, wherein the temperature is 200°C or higher and lower than 270°C.

[0026] 6. The ink composition according to item 1 above, wherein the solvent (c-3) is a mixture of two or more organic solvents containing one or more glycol diether solvents.

[0027] 7. The ink composition according to any one of items 1 to 6 above, wherein the solvent (c-1) is ethylene glycol and the solvent (c-2) is triethylene glycol.

[0028] 8. The ink composition according to any one of items 1 to 7 above, wherein the weight ratio ((c-1):(c-2)) of the solvent (c-1) to the solvent (c-2) is 29:1 to 8:7.

[0029] 9. The ink composition according to any one of items 1 to 8, wherein the weight of the solvent (c-1) is 16 to 29% of the total weight of the liquid carrier (c), and the weight of the solvent (c-2) is 14 to 1% of the total weight of the liquid carrier (c).

[0030] 10. The ink composition according to any one of items 1 to 9 above, wherein the metal oxide nanoparticles (b) comprise B2O3, B2O, SiO2, SiO, GeO2, GeO, As2O4, As2O3, As2O5, Sb2O3, TeO2, SnO2, SnO, or a mixture thereof.

[0031] 11. The ink composition according to item 10 above, wherein the metal oxide nanoparticles (b) contain SiO2.

[0032] 12. The ink composition according to any one of items 1 to 11 above, wherein the charge transporting substance (a) is polythiophene.

[0033] 13. The polythiophene has the following formula (I): [ka] wherein R1 and R2 are each independently H, alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, aryloxy, -SO3M, or -O-[ZO] p -R e or R1 and R2 together form -OZO- (In the formula, M is H, an alkali metal, ammonium, monoalkylammonium, dialkylammonium, or trialkylammonium; Z is a hydrocarbylene group optionally substituted with halogen or Y (wherein Y is a linear or branched alkyl or alkoxyalkyl group having 1 to 10 carbon atoms, and the alkyl or alkoxyalkyl group may be substituted with a sulfonic acid group at any position); p is an integer greater than or equal to 1, and R e is H, alkyl, fluoroalkyl, or aryl)] 13. The ink composition according to item 12 above, wherein the polythiophene contains a repeating unit represented by the following formula:

[0034] 14. R1 and R2 are each independently H, fluoroalkyl, -SO3M, -O[C(R a R b )-C(R c R d )-O] p -R e , or -OR for R1 and R2 together represent -O-(CH2) q -O- (where (CH2) q optionally substituted with Y; where M is H, alkali metal, ammonium, monoalkylammonium, dialkylammonium, or trialkylammonium, and each R a , R b , R c , and R d are each independently H, halogen, alkyl, fluoroalkyl, or aryl; R e is H, alkyl, fluoroalkyl, or aryl; p is 1, 2, or 3; R f 14. The ink composition according to item 13 above, wherein q is alkyl, fluoroalkyl, or aryl; q is 1, 2, or 3; and Y is a linear or branched alkoxyalkyl group having 1 to 10 carbon atoms, which alkoxyalkyl group may be substituted with a sulfonic acid group at any position.

[0035] 15. The ink composition according to item 14 above, wherein R1 is H and R2 is other than H.

[0036] 16. The ink composition according to item 14 above, wherein R1 and R2 are both other than H.

[0037] 17. R1 and R2 are each independently -O[C(R a R b )-C(R c R d )-O] p -R e , or -OR f or R1 and R2 together represent -O-(CH2) q 17. The ink composition according to item 16 above, wherein —O— is formed.

[0038] 18. R1 and R2 are both -O[C(R a R b )-C(R c R d )-O] p -Re 18. The ink composition according to item 17 above, wherein

[0039] 19. Each R a , R b , R c and R d are each independently H, (C-C) alkyl, (C-C) fluoroalkyl, or phenyl; R e 15. The ink composition according to item 14 above, wherein is (C1-C8) alkyl, (C1-C8) fluoroalkyl, or phenyl.

[0040] 20. The polythiophene has the following formula: [ka] wherein M is H, an alkali metal, ammonium, monoalkylammonium, dialkylammonium, or trialkylammonium. 15. The ink composition according to any one of items 12 to 14 above, comprising a repeating unit selected from the group consisting of groups represented by the following formula: and combinations thereof.

[0041] 21. The ink composition according to any one of items 12 to 20 above, wherein the polythiophene is sulfonated.

[0042] 22. The ink composition according to any one of items 12 to 21 above, wherein the polythiophene is sulfonated poly(3-MEET).

[0043] 23. The ink composition according to any one of items 12 to 22, wherein the polythiophene contains repeating units represented by formula (I) in an amount greater than 50 wt %, typically greater than 80 wt %, more typically greater than 90 wt %, and even more typically greater than 95 wt %, based on the total weight of the repeating units.

[0044] 24. The ink composition according to any one of items 1 to 23 above, further comprising one or more synthetic polymers containing an acidic group.

[0045] 25. The ink composition according to paragraph 24, wherein the synthetic polymer is a polymeric acid containing one or more repeating units containing at least one alkyl or alkoxy group substituted with at least one fluorine atom and at least one sulfonic acid (—SO3H) residue, the alkyl or alkoxy group optionally being interrupted by at least one ether bond (—O—).

[0046] 26. The polymer acid comprises a repeating unit represented by the following formula (II) and a repeating unit represented by the following formula (III): [ka] [In the formula, Each of R5, R6, R7, R8, R9, R 10 and R 11 are independently H, halogen, fluoroalkyl, or perfluoroalkyl; X is -[OC(R h R i )-C(R j R k )] q -O-[CR l R m ] z -SO3H, where each R h , R i , R j , R k , R l and R m 26. The ink composition according to item 25 above, wherein: are independently H, halogen, fluoroalkyl, or perfluoroalkyl; q is 0 to 10; and z is 1 to 5.

[0047] 27. The ink composition according to item 24, wherein the synthetic polymer is a polyethersulfone containing one or more repeating units containing at least one sulfonic acid (—SO3H) residue.

[0048] 28. The ink composition according to any one of items 1 to 27 above, further comprising one or more amine compounds.

[0049] 29. The ink composition according to item 28, wherein the amine compound comprises a tertiary alkylamine compound and an amine compound other than a tertiary alkylamine compound.

[0050] 30. The ink composition according to item 29 above, wherein the amine compound other than a tertiary alkylamine compound is a primary alkylamine compound.

[0051] 31. The ink composition according to item 30, wherein the primary alkylamine compound is at least one selected from the group consisting of ethylamine, n-butylamine, t-butylamine, n-hexylamine, 2-ethylhexylamine, n-decylamine, and ethylenediamine.

[0052] 32. The ink composition according to item 30 above, wherein the primary alkylamine compound is 2-ethylhexylamine or n-butylamine. [Effects of the Invention]

[0053] The use of the ink composition of the present invention suppresses the pile-up phenomenon when the ink composition is applied to a liquid-repellent bank substrate and dried to form a charge-transporting thin film, making it easy to obtain a charge-transporting thin film with a uniform thickness. Furthermore, the ink composition of the present invention does not excessively deteriorate the properties of an organic EL device. [Brief explanation of the drawings]

[0054] [Figure 1] 1 is a graph comparing the cross-sectional shapes of the charge-transporting thin films obtained in Examples 1 to 5 and Comparative Example 1. The lower panel is an enlarged view of the portion of the upper panel with openings of 80 to 90 μm. [Figure 2] 1 is a graph comparing the cross-sectional shapes of the charge-transporting thin films obtained in Examples 6 and 7 and Comparative Example 1. The lower panel is an enlarged view of the portion of the upper panel with openings of 80 to 90 μm. DETAILED DESCRIPTION OF THE INVENTION

[0055] As used herein, the terms "a," "an," or "the" mean "one or more" or "at least one," unless otherwise specified.

[0056] As used herein, the term "comprises" encompasses "consisting essentially of" and "consisting of." The term "comprising" encompasses "consisting essentially of" and "consisting of."

[0057] The phrase "free of" means the absence of exogenous addition of the material modified by the phrase, and the absence of detectable amounts of this material observable by analytical techniques known to those skilled in the art (e.g., gas or liquid chromatography, spectrophotometry, light microscopy, etc.).

[0058] Throughout this invention, various publications are incorporated by reference. If the meaning of any language in the publications incorporated herein by reference conflicts with the meaning of the language of the present invention, the meaning of the language of the present invention shall control unless otherwise specified.

[0059] As used herein, in reference to an organic group, "(C x -C y The term "x" (where x and y are each integers) means that the group may contain from x to y carbon atoms in a group.

[0060] As used herein, the term "alkyl" refers to a monovalent linear or branched saturated hydrocarbon group, more typically a monovalent linear or branched saturated (C-C 40 ) refers to hydrocarbon groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, hexyl, 2-ethylhexyl, octyl, hexadecyl, octadecyl, eicosyl, behenyl, triacontyl, and tetracontyl.

[0061] As used herein, the term "fluoroalkyl" refers to an alkyl group as defined herein, more typically (C-C 40 ) alkyl groups. Examples of fluoroalkyl groups include, for example, difluoromethyl, trifluoromethyl, perfluoroalkyl, 1H,1H,2H,2H-perfluorooctyl, perfluoroethyl, and —CH2CF3.

[0062] As used herein, the term "hydrocarbylene" refers to a hydrocarbon, typically (C-C 40 ) refers to a divalent group formed by removing two hydrogen atoms from a hydrocarbon. Hydrocarbylene groups can be linear, branched, or cyclic, and can be saturated or unsaturated. Examples of hydrocarbylene groups include, but are not limited to, methylene, ethylene, 1-methylethylene, 1-phenylethylene, propylene, butylene, 1,2-benzene, 1,3-benzene, 1,4-benzene, and 2,6-naphthalene.

[0063] As used herein, the term "alkoxy" refers to a monovalent group designated as -O-alkyl, where alkyl is defined as herein. Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, and tert-butoxy.

[0064] As used herein, the term "aryl" refers to a monovalent unsaturated hydrocarbon group containing one or more six-membered carbon rings, where the unsaturation can be represented by three conjugated double bonds. Aryl groups include monocyclic aryls and polycyclic aryls. Polycyclic aryls refer to a monovalent unsaturated hydrocarbon group containing two or more six-membered carbon rings, where the unsaturation can be represented by three conjugated double bonds, where adjacent rings are bonded to each other or fused together by one or more bonds or divalent bridging groups. Examples of aryl groups include, but are not limited to, phenyl, anthracenyl, naphthyl, phenanthrenyl, fluorenyl, and pyrenyl.

[0065] As used herein, the term "aryloxy" refers to a monovalent group designated as -O-aryl, where aryl is defined herein. Examples of aryloxy groups include, but are not limited to, phenoxy, anthracenoxy, naphthoxy, phenanthrenoxy, and fluorenoxy.

[0066] Any substituent or group described herein may be optionally substituted at one or more carbon atoms with one or more of the same or different substituents described herein. For example, a hydrocarbylene group may be further substituted with an aryl or alkyl group. Any substituent or group described herein may also be optionally substituted at one or more carbon atoms with one or more substituents selected from the group consisting of, for example, halogens such as F, Cl, Br, and I; nitro (NO), cyano (CN), and hydroxy (OH).

[0067] As used herein, "hole carrier compound" refers to any compound that can facilitate the movement of holes (i.e., positive charge carriers) and / or block the movement of electrons, for example, in an electronic device. Hole carrier compounds include compounds useful in layers (HTL), hole injection layers (HIL), and electron blocking layers (EBL) of electronic devices, typically organic electronic devices (e.g., organic light emitting devices, etc.).

[0068] As used herein, the term "doped" with respect to a hole carrier compound, e.g., polythiophene, means that the hole carrier compound has undergone a chemical transformation, typically an oxidation or reduction reaction, more typically an oxidation reaction, facilitated by a dopant. As used herein, the term "dopant" refers to a substance that oxidizes or reduces, typically oxidizes, the hole carrier compound, e.g., polythiophene. Herein, the process by which the hole carrier compound undergoes a chemical transformation, typically an oxidation or reduction reaction, more typically an oxidation reaction, facilitated by a dopant is referred to as a "doping reaction" or simply "doping." Doping alters the properties of the polythiophene, which may include, but are not limited to, electrical properties (such as resistivity and work function), mechanical properties, and optical properties. During the doping reaction, the hole carrier compound becomes charged, and the dopant becomes an oppositely charged counterion to the doped hole carrier compound as a result of the doping reaction. As used herein, a substance must chemically react with, oxidize, or reduce, typically oxidize, a hole carrier compound to be called a dopant. Substances that do not react with a hole carrier compound but can act as counterions are not considered dopants in the present invention. Thus, the term "undoped" with respect to a hole carrier compound, e.g., polythiophene, means that the hole carrier compound has not undergone a doping reaction as described herein.

[0069] The present invention provides an ink composition comprising: (a) Charge transporting substance; (b) one or more metal oxide nanoparticles; and (c) a liquid carrier, (c-1) Boiling point bp 1 a first hydrophilic glycol-based solvent having a viscosity of (°C); (c-2) Boiling point bp 2 a second hydrophilic glycol-based solvent having a temperature of (°C), and (c-3) Boiling point bp 3 (°C) Including, bp 1 <bp 3 <bp 2 a liquid carrier The present invention relates to an ink composition comprising:

[0070] The ink composition of the present disclosure may be non-aqueous or may contain water. However, from the viewpoints of process compatibility in inkjet coating, storage stability of the ink, and reducing the voltage or extending the life of an OLED using a charge-transporting thin film obtained from the composition, a non-aqueous system is preferred. As used herein, "non-aqueous" means that the total amount of water in the ink composition of the present disclosure is 0 to 2 wt % based on the total amount of the ink composition. Typically, the total amount of water in the ink composition is 0 to 1 wt %, more typically 0 to 0.5 wt %, based on the total amount of the ink composition. In some embodiments, the ink composition of the present disclosure is substantially free of water.

[0071] The ink composition of the present invention contains a charge transporting substance (a). Although various substances that can be used as the charge transporting substance (a) are known, in the present invention, it is preferable to use polythiophene as the charge transporting substance (a). The polythiophene that can be used as the charge transport material (a) in the present invention is a compound having an average molecular weight of 1,000 to 1,000,000 and composed of multiple structural units (which may be the same or different) derived from a thiophene derivative. In the polythiophene, two adjacent structural units are bonded to each other. When the polythiophene contains two or more different types of structural units, the structural units may be arranged in any order. In a preferred embodiment, from the viewpoint of reproducibly obtaining a charge-transporting thin film that has excellent flatness and provides excellent life characteristics when applied to an organic EL device, the polythiophene compound contained in the composition of the present invention does not include poly(3,4-ethylenedioxythiophene) (PEDOT). In one embodiment of the present invention, the polythiophene compound contained in the composition of the present invention does not contain a fluorine atom, from the viewpoint of obtaining a composition that provides a charge-transporting thin film that can suppress repellency of a coating film when a functional film is formed thereon by coating and can reproducibly realize a film with excellent flatness.

[0072] Polythiophenes suitable for use in the present disclosure have the following formula (I): [ka] wherein R1 and R2 are each independently H, alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, aryloxy, -SO3M, or -O-[ZO] p -R e or R1 and R2 together form -OZO-, where M is H, an alkali metal, ammonium, monoalkylammonium, dialkylammonium, or trialkylammonium, Z is a hydrocarbylene group optionally substituted with halogen or Y (wherein Y is a linear or branched alkyl or alkoxyalkyl group having 1 to 10 carbon atoms, and the alkyl or alkoxyalkyl group may be substituted at any position with a sulfonic acid group), p is an integer of 1 or greater, and R eis H, alkyl, fluoroalkyl, or aryl] The polythiophene may be used alone or in combination of two or more kinds.

[0073] In one embodiment, R and R are each independently H, fluoroalkyl, —SOM, —O[C(R a R b )-C(R c R d )-O] p -R e , or -OR f or R1 and R2 together represent -O-(CH2) q -O- (where (CH2) q optionally substituted with Y; where M is H, alkali metal, ammonium, monoalkylammonium, dialkylammonium, or trialkylammonium, and each R a , R b , R c , and R d are each independently H, halogen, alkyl, fluoroalkyl, or aryl; R e is H, alkyl, fluoroalkyl, or aryl; p is 1, 2, or 3; R f is alkyl, fluoroalkyl, or aryl; q is 1, 2, or 3, and Y is a linear or branched alkoxyalkyl group having 1 to 10 carbon atoms, which may be substituted with a sulfonic acid group at any position.

[0074] In one embodiment, R1 is H and R2 is other than H. In such an embodiment, the repeat unit is derived from a 3-substituted thiophene.

[0075] Polythiophenes can be regiorandom or regioregular compounds. Due to their asymmetric structure, polymerization of 3-substituted thiophenes produces a mixture of polythiophene structures containing three possible positional chemical bonds between the repeating units. The three available orientations when two thiophene rings are joined are 2,2', 2,5', and 5,5' couplings. 2,2' (i.e., head-to-head) coupling and 5,5' (i.e., tail-to-tail) coupling are referred to as regiorandom couplings. In contrast, 2,5' (i.e., head-to-tail) coupling is referred to as regioregular coupling. The degree of regioregularity can be, for example, about 0-100%, or about 25-99.9%, or about 50-98%. Regioregularity can be determined by standard methods known to those skilled in the art, such as using NMR spectroscopy.

[0076] In some embodiments, the polythiophene is regioregular. In some embodiments, the regioregularity of the polythiophene may be at least about 85%, typically at least about 95%, and more typically at least about 98%. In some embodiments, the degree of regioregularity may be at least about 70%, typically at least about 80%. In yet other embodiments, the regioregular polythiophene has a degree of regioregularity of at least about 90%, typically at least about 98%.

[0077] 3-Substituted thiophene monomers, including polymers derived therefrom, are commercially available or can be prepared by methods known to those skilled in the art. Methods of synthesis, doping, and polymer characterization, including regioregular polythiophenes with pendant groups, are provided, for example, in U.S. Patent No. 6,602,974 to McCullough et al. and U.S. Patent No. 6,166,172 to McCullough et al.

[0078] In another embodiment, R1 and R2 are both other than H. In such an embodiment, the repeat unit is derived from a 3,4-disubstituted thiophene.

[0079] In one embodiment, R1 and R2 are each independently —O[C(R a R b )-C(R c R d )-O] p -R e , or -OR f or R1 and R2 together represent -O-(CH2) q In one embodiment, R1 and R2 both form -O[C(R a R b )-C(R c R d )-O] p -R e R1 and R2 may be the same or different.

[0080] In one embodiment, each R a , R b , R c , and R d are each independently H, (C-C) alkyl, (C-C) fluoroalkyl, or phenyl; and R e is (C1-C8) alkyl, (C1-C8) fluoroalkyl, or phenyl.

[0081] In one embodiment, R1 and R2 are each -O[CH2-CH2-O] p -R e In one embodiment, R1 and R2 are each -O[CH(CH3)-CH2-O] p -R e is.

[0082] In one embodiment, R e is methyl, propyl, or butyl.

[0083] In one embodiment, q is 2.

[0084] In one embodiment, —O—(CH) q-O- is substituted at one or more positions with Y. In one embodiment, -O-(CH) q -O- is substituted with Y at one position.

[0085] In one embodiment, q is 2 and Y is a 3-sulfobutoxymethyl group, in which case the -O-(CH)-O- group is preferably substituted at one position with a 3-sulfobutoxymethyl group.

[0086] In one embodiment, the polythiophene has the formula: [ka] wherein M is H, an alkali metal, ammonium, monoalkylammonium, dialkylammonium, or trialkylammonium, and combinations thereof.

[0087] As will be apparent to those skilled in the art, the following formula: [ka] The repeating unit represented by the following formula: [ka] 3-(2-(2-methoxyethoxy)ethoxy)thiophene (referred to herein as 3-MEET) and is derived from a monomer represented by the structure: [ka] The repeating unit represented by the following formula: [ka] wherein M is H, an alkali metal, ammonium, monoalkylammonium, dialkylammonium, or trialkylammonium. Sulfonated 3-(2-(2-methoxyethoxy)ethoxy)thiophene (referred to herein as sulfonated 3-MEET) and is derived from a monomer represented by the structure: [ka] The repeating unit represented by the following formula: [ka] 3,4-bis(2-(2-butoxyethoxy)ethoxy)thiophene (referred to herein as 3,4-diBEET) and is derived from a monomer represented by the structure: [ka] The repeating unit represented by the following formula: [ka] 3,4-bis((1-propoxypropan-2-yl)oxy)thiophene (referred to herein as 3,4-diPPT) and is derived from a monomer represented by the structure shown in the formula: [ka] The repeating unit represented by the following formula: [ka] 3,4-ethylenedioxythiophene It is derived from a monomer represented by the structure shown below.

[0088] 3,4-Disubstituted thiophene monomers, including polymers derived therefrom, are commercially available or can be prepared by methods known to those skilled in the art. For example, 3,4-disubstituted thiophene monomers can be prepared by reacting 3,4-dibromothiophene with a compound of the formula: HO-[ZO] p -R e or HOR f [where Z, R e , R f and p is as defined herein] with a metal salt, typically the sodium salt.

[0089] Polymerization of 3,4-disubstituted thiophene monomers is carried out by first brominating the 2- and 5-positions of the 3,4-disubstituted thiophene monomer to form the corresponding 2,5-dibromo derivative of the 3,4-disubstituted thiophene monomer. The polymer can then be obtained by GRIM (Grignard metathesis) polymerization of the 2,5-dibromo derivative of the 3,4-disubstituted thiophene in the presence of a nickel catalyst. Such a method is described, for example, in U.S. Pat. No. 8,865,025, which is incorporated herein by reference in its entirety. Another known method for polymerizing thiophene monomers is by oxidative polymerization using metal-free organic oxidants such as 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or transition metal halides such as iron(III) chloride, molybdenum(V) chloride, and ruthenium(III) chloride.

[0090] which can be converted to a metal salt, typically the sodium salt, and used to generate 3,4-disubstituted thiophene monomers, of the formula: HO-[ZO] p -R e or HOR fExamples of compounds having the formula (I) are trifluoroethanol, ethylene glycol monohexyl ether (hexyl cellosolve), propylene glycol monobutyl ether (Dowanol™ PnB), diethylene glycol monoethyl ether (ethyl carbitol), dipropylene glycol n-butyl ether (Dowanol™ DPnB), diethylene glycol monophenyl ether (phenyl carbitol), ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monobutyl ether (butyl carbitol), dipropylene glycol monomethyl ether (Dowanol™ DPM), diisobutyl carbinol, 2-ethylhexyl alcohol, methyl isobutyl carbinol, ethylene glycol monophenyl ether (Dowanol™ Eph), propylene glycol monopropyl ether (Dowanol™ PnP), propylene glycol monophenyl ether (Dowanol™ PPh), diethylene glycol monopropyl ether (propyl carbitol), diethylene glycol monohexyl ether (hexyl carbitol), 2-ethylhexyl carbitol, dipropylene glycol monopropyl ether (Dowanol™ DPnP), tripropylene glycol monomethyl ether (Dowanol™ TPM), diethylene glycol monomethyl ether (methyl carbitol), and tripropylene glycol monobutyl ether (Dowanol™ TPnB).

[0091] Polythiophenes having repeating units of formula (I) of the present disclosure can be further modified following their formation by polymerization. For example, polythiophenes having one or more repeating units derived from 3-substituted thiophene monomers may have one or more sites where hydrogen can be replaced with a substituent, such as a sulfonic acid group (—SO3H), by sulfonation.

[0092] As used herein, the term "sulfonated" in reference to a polythiophene means that the polythiophene contains one or more sulfonic acid groups (-SO3H). (Such polythiophenes are also referred to as "sulfonated polythiophenes.") Typically, the sulfur atom of the —SO3H group is directly attached to the polythiophene backbone, not to a side group. For purposes of this disclosure, a side group is a monovalent group whose theoretical or actual elimination from the polymer does not shorten the length of the polymer chain. Sulfonated polythiophene polymers and / or copolymers can be prepared using any method known to those skilled in the art. For example, polythiophenes can be sulfonated by reacting them with sulfonating reagents, such as oleum, acetyl sulfate, pyridine SO3, and the like. In another example, monomers can be sulfonated using sulfonating reagents and then polymerized by known methods and / or the methods described herein. As will be apparent to those skilled in the art, sulfonic acid groups can result in the formation of corresponding salts or adducts in the presence of basic compounds, such as alkali metal hydroxides, ammonia, and alkylamines (e.g., mono-, di-, and trialkylamines, e.g., triethylamine, etc.). Thus, the term "sulfonated" in reference to a polythiophene means that the polythiophene has one or more -SO3M groups, where M is an alkali metal ion (e.g., Na + , Li + , K. + , Rb + , Cs + etc.), ammonium (NH4 + ), mono-, di-, and trialkylammonium (such as triethylammonium).

[0093] Sulfonation of conjugated polymers and sulfonated conjugated polymers (including sulfonated polythiophenes) are described in US Pat. No. 8,017,241 to Seshadri et al., which is incorporated herein by reference in its entirety. Sulfonated polythiophenes are also described in WO 2008 / 073149 and WO 2016 / 171935, which are incorporated herein by reference in their entireties.

[0094] In one embodiment, the polythiophene is sulfonated.

[0095] In one embodiment, the sulfonated polythiophene has the following formula (I): [ka] wherein R1 and R2 are each independently H, alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, aryloxy, or -O-[ZO] p -R e wherein Z is an optionally halogenated hydrocarbylene group, p is an integer equal to or greater than 1, and R e is H, alkyl, fluoroalkyl, or aryl). However, either R1 or R2 is -SO3M (M is H, an alkali metal, ammonium, monoalkylammonium, dialkylammonium, or trialkylammonium). It contains a repeating unit represented by the formula:

[0096] In some embodiments, the sulfonated polythiophene has the formula (I): a R b )-C(R c R d )-O] p -R e , or -OR f where each R a , R b , R c , and R d are each independently H, halogen, alkyl, fluoroalkyl, or aryl; R eis H, alkyl, fluoroalkyl, or aryl; p is 1, 2, or 3; and R f is alkyl, fluoroalkyl, or aryl. However, either R1 or R2 is -SO3M (M is H, an alkali metal, ammonium, monoalkylammonium, dialkylammonium, or trialkylammonium). It contains a repeating unit represented by the formula:

[0097] In certain embodiments, R1 is -SO3M (M is H, an alkali metal, ammonium, monoalkylammonium, dialkylammonium, or trialkylammonium), and R2 is other than -SO3M. M is preferably monoalkylammonium, dialkylammonium, or trialkylammonium, more preferably trialkylammonium.

[0098] In certain embodiments, R1 is -SO3M and R2 is -O[C(R a R b )-C(R c R d )-O] p -R e , or -OR f is.

[0099] In certain embodiments, R1 is -SO3M and R2 is -O[C(R a R b )-C(R c R d )-O] p -R e is.

[0100] In certain embodiments, R1 is -SO3M and R2 is -O-CH2CH2-O-CH2CH2-O-CH3.

[0101] In some embodiments, the sulfonated polythiophene has the following formula (I): [ka] wherein R1 and R2 are each independently H, alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, aryloxy, or -O-[ZO] p -R e wherein Z is an optionally halogenated hydrocarbylene group, p is an integer equal to or greater than 1, and R e is H, alkyl, fluoroalkyl, or aryl). The polythiophene is obtained by sulfonating a polythiophene containing a repeating unit represented by the formula:

[0102] In some embodiments, the sulfonated polythiophene has the formula (I): a R b )-C(R c R d )-O] p -R e , or -OR f where each R a , R b , R c , and R d are each independently H, halogen, alkyl, fluoroalkyl, or aryl; R e is H, alkyl, fluoroalkyl, or aryl; p is 1, 2, or 3; and R f is alkyl, fluoroalkyl, or aryl.

[0103] In certain embodiments, R1 is H and R2 is other than H. In such embodiments, the repeat unit is derived from a 3-substituted thiophene.

[0104] Sulfonated polythiophenes are derived from polythiophenes, which can be regiorandom or regioregular compounds. Due to their asymmetric structure, polymerization of 3-substituted thiophenes produces a mixture of polythiophene structures containing three possible positional chemical bonds between the repeating units. The three available orientations when two thiophene rings are joined are 2,2', 2,5', and 5,5' couplings. 2,2' (i.e., head-to-head) coupling and 5,5' (i.e., tail-to-tail) coupling are referred to as regiorandom couplings. In contrast, 2,5' (i.e., head-to-tail) coupling is referred to as regioregular coupling. The degree of regioregularity can be, for example, about 0-100%, about 25-99.9%, or about 50-98%. Regioregularity can be determined by standard methods known to those skilled in the art, such as using NMR spectroscopy.

[0105] 3-Substituted thiophene monomers, including polymers derived therefrom, are commercially available or can be prepared by methods known to those skilled in the art. Synthetic methods, doping methods, and polymer characterization, including regioregular polythiophenes with pendant groups, are provided, for example, in U.S. Patent No. 6,602,974 to McCullough et al. and U.S. Patent No. 6,166,172 to McCullough et al. Sulfonation of conjugated polymers and sulfonated conjugated polymers, including sulfonated polythiophenes, is described in U.S. Patent No. 8,017,241 to Seshadri et al.

[0106] In some embodiments, R1 is H and R2 is —O[C(R a R b )-C(R c R d )-O] p -R e , or -OR f In some embodiments, R1 is H and R2 is —O[C(R a R b )-C(R c R d )-O] p-R e is.

[0107] In certain embodiments, each R a , R b , R c , and R d are each independently H, (C-C) alkyl, (C-C) fluoroalkyl, or phenyl; R e and R f are each independently H, (C1-C8) alkyl, (C1-C8) fluoroalkyl, or phenyl.

[0108] In certain embodiments, R2 is -O[CH2-CH2-O] p -R e In some embodiments, R2 is -OR f is.

[0109] It can be converted to a metal salt, typically the sodium salt, and attached to a thiophene monomer to form a 3-substituted thiophene, which can then be used to generate the polythiophene to be sulfonated, of the formula: HO[C(R a R b )-C(R c R d )-O] p -R e or HOR fExamples of compounds having the formula (I) are trifluoroethanol, ethylene glycol monohexyl ether (hexyl cellosolve), propylene glycol monobutyl ether (Dowanol™ PnB), diethylene glycol monoethyl ether (ethyl carbitol), dipropylene glycol n-butyl ether (Dowanol™ DPnB), diethylene glycol monophenyl ether (phenyl carbitol), ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monobutyl ether (butyl carbitol), dipropylene glycol monomethyl ether (Dowanol™ DPM), diisobutyl carbinol, 2-ethylhexyl alcohol, methyl isobutyl carbinol, ethylene glycol monophenyl ether (Dowanol™ Eph), propylene glycol monopropyl ether (Dowanol™ PnP), propylene glycol monophenyl ether (Dowanol™ PPh), diethylene glycol monopropyl ether (propyl carbitol), diethylene glycol monohexyl ether (hexyl carbitol), 2-ethylhexyl carbitol, dipropylene glycol monopropyl ether (Dowanol™ DPnP), tripropylene glycol monomethyl ether (Dowanol™ TPM), diethylene glycol monomethyl ether (methyl carbitol), and tripropylene glycol monobutyl ether (Dowanol™ TPnB).

[0110] In some embodiments, R e is H, methyl, propyl, or butyl. In certain embodiments, R f is CH2CF3.

[0111] In some embodiments, the sulfonated polythiophene has the formula: [ka] It can be obtained by sulfonating a polythiophene containing a repeating unit represented by the formula:

[0112] As will be apparent to those skilled in the art, the following formula: [ka] The repeating unit represented by the following formula: [ka] 3-(2-(2-methoxyethoxy)ethoxy)thiophene (referred to herein as 3-MEET) It is derived from a monomer represented by the structure shown below.

[0113] Therefore, the following formula: [ka] Sulfonation of polythiophenes containing the repeating unit: gives sulfonated poly(3-MEET).

[0114] In some embodiments, the polythiophene is sulfonated poly(3-MEET).

[0115] The polythiophenes used in the present disclosure can be homopolymers or copolymers (including statistical, random, gradient, and block copolymers). For polymers containing monomers A and B, block copolymers include, for example, AB diblock copolymers, ABA triblock copolymers, and -(AB) k -including multi-block copolymers. Polythiophenes may also contain repeat units derived from other types of monomers, such as thienothiophenes, selenophenes, pyrroles, furans, tellurophenes, anilines, arylamines, and arylenes (such as phenylene, phenylenevinylene, and fluorene).

[0116] In some embodiments, the polythiophene comprises repeat units represented by Formula (I) in an amount greater than 50 wt%, typically greater than 80 wt%, more typically greater than 90 wt%, and even more typically greater than 95 wt%, based on the total weight of the repeat units.

[0117] As will be apparent to those skilled in the art, depending on the purity of the starting monomer compounds used in polymerization, the polymer formed may contain repeat units derived from impurities.As used herein, the term "homopolymer" refers to a polymer that contains repeat units derived from one type of monomer, but may contain repeat units derived from impurities.In some embodiments, the polythiophene is a homopolymer in which essentially all repeat units are repeat units represented by formula (I).

[0118] Polythiophenes typically have a number average molecular weight of about 1,000 to 1,000,000 g / mol. More typically, the conjugated polymers have a number average molecular weight of about 5,000 to 100,000 g / mol, and even more typically, about 10,000 to about 50,000 g / mol. Number average molecular weights can be determined by methods known to those skilled in the art, such as, for example, gel permeation chromatography.

[0119] In one embodiment, the polythiophene is used after treatment with a reducing agent. In conjugated polymers such as polythiophenes, some of the repeating units constituting them may have an oxidized chemical structure called a "quinoid structure." The term "quinoid structure" is used in contrast to the term "benzenoid structure." The latter is a structure containing an aromatic ring, while the former refers to a structure in which a double bond within the aromatic ring moves out of the ring (resulting in the disappearance of the aromatic ring), resulting in the formation of two exocyclic double bonds conjugated with other double bonds remaining in the ring. Those skilled in the art can easily understand the relationship between these two structures from the relationship between the structures of benzoquinone and hydroquinone. Quinoid structures for the repeating units of various conjugated polymers are well known to those skilled in the art. The quinoid structure corresponding to the repeating unit of polythiophene represented by the above formula (I) is shown in the following formula (I'). [ka] wherein R1 and R2 are as defined in formula (I).

[0120] This quinoid structure is formed by the doping reaction and forms part of structures known as "polaron structures" and "bipolaron structures," which impart charge transport properties to conjugated polymers such as polythiophene. These structures are publicly known. The introduction of a "polaron structure" and / or a "bipolaron structure" is essential in the fabrication of organic EL devices. In fact, this is achieved by intentionally inducing the doping reaction when baking a charge-transporting thin film formed from a charge-transporting varnish during the fabrication of organic EL devices. The quinoid structure is contained in the conjugated polymer prior to the doping reaction, presumably because the conjugated polymer underwent an unintended oxidation reaction equivalent to the doping reaction during its production process (particularly, the sulfonation step when sulfonating the conjugated polymer).

[0121] There is a correlation between the amount of quinoid structures contained in polythiophene and the dispersibility of polythiophene in organic solvents; as the amount of quinoid structures increases, the dispersibility decreases. Therefore, the introduction of quinoid structures after the formation of a charge-transporting thin film from an ink composition does not cause any problems. However, if an excessive amount of quinoid structures is introduced into polythiophene due to the unintended oxidation reaction, it will cause problems during the production of the ink composition. It is known that the dispersibility of polythiophene in organic solvents can vary from product to product. One of the reasons for this is thought to be that the amount of quinoid structures introduced into polythiophene due to the unintended oxidation reaction varies depending on the production conditions of each polythiophene. Therefore, when polythiophene is subjected to a reduction treatment using a reducing agent, even if an excessive amount of quinoid structures has been introduced into the polythiophene, the quinoid structures are reduced by the reduction, improving the dispersibility of the polythiophene in organic solvents, and making it possible to stably produce an excellent ink composition that gives a charge-transporting thin film with excellent homogeneity.

[0122] The reducing agent used in this reduction treatment is not particularly limited as long as it can reduce the quinoid structure of polythiophene represented by the formula (I') and convert it to a non-oxidized structure, i.e., the benzenoid structure of polythiophene represented by the formula (I), and it is preferable to use, for example, aqueous ammonia, hydrazine, etc. The amount of the reducing agent is usually 0.1 to 10 parts by weight, preferably 0.5 to 2 parts by weight, per 100 parts by weight of polythiophene to be treated.

[0123] The method and conditions for the reduction treatment are not particularly limited. For example, this treatment can be carried out by simply contacting the polythiophene with a reducing agent in the presence or absence of a suitable solvent. Usually, reduction treatment under relatively mild conditions, such as stirring the polythiophene in 28% aqueous ammonia (e.g., overnight at room temperature), sufficiently improves the dispersibility of the polythiophene in organic solvents. When the polythiophene is sulfonated, the sulfonated polythiophene may be converted into the corresponding ammonium salt, such as a trialkylammonium salt (sulfonated polythiophene amine adduct), if necessary, and then subjected to the reduction treatment.

[0124] The reduction treatment changes the dispersibility of the polythiophene in the solvent, and as a result, polythiophene that was not dissolved in the reaction system at the start of the treatment may dissolve by the end of the treatment. In such cases, the polythiophene can be recovered by adding an organic solvent that is incompatible with polythiophene (e.g., acetone or isopropyl alcohol) to the reaction system to precipitate the polythiophene, followed by filtration.

[0125] The ink compositions of the present disclosure may optionally further comprise other hole carrier compounds.

[0126] Optional hole carrier compounds include, for example, low molecular weight compounds or high molecular weight compounds. Optional hole carrier compounds may be non-polymeric or polymeric. Non-polymeric hole carrier compounds include, but are not limited to, crosslinkable and non-crosslinkable small molecules. Examples of non-polymeric hole carrier compounds are N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine (CAS # 65181-78-4); N,N'-bis(4-methylphenyl)-N,N'-bis(phenyl)benzidine; N,N'-bis(2-naphthalenyl)-N,N'-bis(phenylbenzidine) (CAS # 139255-17-1); 1,3,5-tris(3-methyldiphenylamino)benzene (also known as m-MTDAB); N,N'-bis(1-naphthalenyl)-N,N'-bis(phenyl)benzidine (CAS # 123847-85-8, NPB); 4,4',4"-tris(N,N-phenyl-3-methylphenylamino)triphenylamine (also known as m-MTDATA, CAS # 124729-98-2;4,4'N,N'-Diphenylcarbazole (also known as CBP, CAS # 58328-31-7);1,3,5-Tris(diphenylamino)benzene;1,3,5-Tris(2-(9-ethylcarbazyl-3)ethylene)benzene;1,3,5-Tris[(3-methylphenyl)phenylamino]benzene;1,3-Bis(N-carbazolyl)benzene;1,4-Bis(diphenylamino)benzene;4,4'-Bis(N-carbazolyl)-1,1'-biphenyl;4,4'-Bis(N-carbazolyl)-1,1'-biphenyl;4-(Dibenzylamino)benzaldehyde-N,N-diphenylhydrazone;4-(Diethylamino)benzaldehyde diphenylhydrazone;4-(Dimethylamino)benzaldehyde Diphenylhydrazone;4-(Diphenylamino)benzaldehyde diphenylhydrazone;9-Ethyl-3-carbazolecarboxaldehyde diphenylhydrazone;Copper(II) phthalocyanine;N,N'-Bis(3-methylphenyl)-N,N'-diphenylbenzidine;N,N'-Di[(1-naphthyl)-N,N'-diphenyl]-1,1'-biphenyl)-4,4'-diamine;Examples of suitable amines include, but are not limited to, N,N'-diphenyl-N,N'-di-p-tolylbenzene-1,4-diamine; tetra-N-phenylbenzidine; titanyl phthalocyanine; tri-p-tolylamine; tris(4-carbazol-9-ylphenyl)amine; and tris[4-(diethylamino)phenyl]amine.

[0127] Optional polymeric hole carrier compounds include, but are not limited to, poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)]; poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N'-bis{p-butylphenyl}-1,1'-biphenylene-4,4'-diamine)]; poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine) (also known as TFB), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] (commonly referred to as poly-TPD).

[0128] Other optional hole carrier compounds are described, for example, in U.S. Patent Publication Nos. 2010 / 0292399, published November 18, 2010; 2010 / 010900, published May 6, 2010; and 2010 / 0108954, published May 6, 2010. The optional hole carrier compounds described herein are known in the art and commercially available.

[0129] Polythiophenes comprising repeat units according to formula (I) may be doped or undoped.

[0130] In some embodiments, the polythiophene comprising a repeating unit according to formula (I) is doped with a dopant. Dopants are known in the art. For example, see U.S. Patent No. 7,070,867; U.S. Publication No. 2005 / 0123793; and U.S. Publication No. 2004 / 0113127. The dopant may be an ionic compound. The dopant may include cations and anions. One or more dopants may be used to dope the polythiophene comprising a repeating unit according to formula (I).

[0131] The cation of the ionic compound can be, for example, V, Cr, Mn, Fe, Co, Ni, Cu, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Ta, W, Re, Os, Ir, Pt, or Au.

[0132] The cations of the ionic compounds can be, for example, gold, molybdenum, rhenium, iron, and silver cations.

[0133] In some embodiments, the dopant may comprise a sulfonate or carboxylate, including alkyl, aryl, and heteroaryl sulfonates or carboxylates. As used herein, "sulfonate" refers to a -SO3M group (where M is H). + or alkali metal ions (e.g., Na + , Li + , K. + , Rb + , Cs + etc.); or ammonium (NH4 + As used herein, "carboxylate" refers to a -COM group, where M is H + or alkali metal ions (e.g., Na + , Li + , K. + , Rb + , Cs + etc.); or ammonium (NH4 +Examples of sulfonate and carboxylate dopants include, but are not limited to, benzoate compounds, heptafluorobutyrate, methanesulfonate, trifluoromethanesulfonate, p-toluenesulfonate, pentafluoropropionate, and polymeric sulfonates, perfluorosulfonate-containing ionomers, and the like.

[0134] In some embodiments, the dopant does not include a sulfonate or a carboxylate.

[0135] In some embodiments, the dopant may include sulfonylimides (e.g., bis(trifluoromethanesulfonyl)imides, etc.); antimonates (e.g., hexafluoroantimonates, etc.); arsenates (e.g., hexafluoroarsenates, etc.); phosphorus compounds (e.g., hexafluorophosphates, etc.); and borates (e.g., tetrafluoroborate, tetraarylborates, and trifluoroborates, etc.). Examples of tetraarylborates include, but are not limited to, halogenated tetraarylborates such as tetrakispentafluorophenylborate (TPFB). Examples of trifluoroborates include, but are not limited to, (2-nitrophenyl)trifluoroborate, benzofurazan-5-trifluoroborate, pyrimidine-5-trifluoroborate, pyridine-3-trifluoroborate, and 2,5-dimethylthiophene-3-trifluoroborate.

[0136] As disclosed herein, polythiophenes can be doped with dopants. The dopant can be, for example, a material that undergoes one or more electron transfer reactions with the polythiophene to produce a doped polythiophene. The dopant can be selected to provide appropriate charge-balancing counteranions. The reaction can occur by mixing the polythiophene with the dopant, as is known in the art. For example, the dopant can undergo spontaneous electron transfer from the polymer to a cation-anion dopant (e.g., a metal salt), leaving the conjugated polymer in its oxidized form with an associated anion and free metal. See, for example, Lebedev et al., Chem. Mater., 1998, 10, 156-163. As disclosed herein, polythiophenes and dopants can refer to components that react to form a doped polymer. The doping reaction can be a charge transfer reaction in which charge carriers are generated, and the reaction can be reversible or irreversible. In some embodiments, silver ions can undergo electron transfer to or from silver metal and the doped polymer.

[0137] In the final formulation, the composition may be distinct from the original combination of components (i.e., the polythiophene and / or dopant may or may not be present in the final composition in the same form as before mixing).

[0138] In some embodiments, reaction by-products from the doping process may be removed, for example, metals such as silver may be removed by filtration.

[0139] For example, materials can be purified to remove halogens and metals. Halogens include, for example, chlorides, bromides, and iodides. Metals include, for example, dopant cations (including reduced forms of dopant cations) or metals left over from catalyst or initiator residues. Metals include, for example, silver, nickel, and magnesium. The amount can be, for example, less than 100 ppm, or less than 10 ppm, or less than 1 ppm.

[0140] Metal content, including silver content, can be measured by ICP-MS, especially at concentrations above 50 ppm.

[0141] In some embodiments, when the polythiophene is doped with a dopant, the polythiophene and the dopant are mixed to form a doped polymer composition. Mixing can be accomplished using any method known to those skilled in the art. For example, a solution containing the polythiophene can be mixed with another solution containing the dopant. The solvent used to dissolve the polythiophene and the dopant can be one or more of the solvents described herein. The reaction can occur by mixing the polythiophene and the dopant, as known in the art. The resulting doped polythiophene composition comprises, based on the composition, about 40% to 75% by weight of the polymer and about 25% to 55% by weight of the dopant. In another embodiment, the doped polythiophene composition comprises, based on the composition, about 50% to 65% by weight of the polythiophene and about 35% to 50% by weight of the dopant. Typically, the weight of the polythiophene is greater than the weight of the dopant. Typically, the dopant may be a silver salt such as silver tetrakis(pentafluorophenyl)borate in an amount of about 0.25 to 0.5 m / ru (where m is the molar amount of silver salt and ru is the molar amount of polymer repeat units).

[0142] The doped polythiophene is isolated by methods known to those skilled in the art (e.g., by rotary evaporation of the solvent) to obtain a dry or substantially dry material (e.g., a powder). The amount of residual solvent can be, for example, 10% by weight or less, or 5% by weight or less, or 1% by weight or less, based on the dry or substantially dry material. The dry or substantially dry powder can be redispersed or redissolved in one or more fresh solvents.

[0143] The ink composition of the present invention contains one or more metal oxide nanoparticles (b). Nanoparticles refer to fine particles whose primary particles have an average particle size on the order of nanometers (typically 500 nm or less). Metal oxide nanoparticles refer to metal oxides formed into nanoparticles.

[0144] The metal in the metal oxide nanoparticles (b) includes not only metals in the usual sense but also semimetals. The metals in the usual sense may be used alone or in combination of two or more, and are preferably one or more selected from the group consisting of tin (Sn), titanium (Ti), aluminum (Al), zirconium (Zr), zinc (Zn), niobium (Nb), tantalum (Ta), and W (tungsten). However, they are not limited thereto. On the other hand, a metalloid refers to an element whose chemical and / or physical properties are intermediate between those of a metal and a nonmetal. Although a universal definition of a metalloid has not been established, in the present invention, a total of six elements, namely, boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te), are defined as metalloids. These metalloids may be used alone or in combination with two or more of them, or may be used in combination with metals in the usual sense.

[0145] The metal oxide nanoparticles (b) preferably contain an oxide of one or more metals selected from the group consisting of boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), tin (Sn), titanium (Ti), aluminum (Al), zirconium (Zr), zinc (Zn), niobium (Nb), tantalum (Ta), and tungsten (W). When the metal is a combination of two or more metals, the metal oxide may be a mixture of oxides of individual metals or a composite oxide containing multiple metals. Specific examples of metal oxides include, but are not limited to, BO, BO, SiO, SiO, GeO, GeO, AsO, AsO, AsO, AsO, SbO, SbO, TeO, SnO, ZrO, AlO, and ZnO.

[0146] In one embodiment, the metal oxide nanoparticles (b) comprise B2O3, B2O, SiO2, SiO2, GeO2, GeO, As2O4, As2O3, As2O5, SnO2, SnO, Sb2O3, TeO2, or mixtures thereof. In another embodiment, the metal oxide nanoparticles (b) comprise SiO2.

[0147] Regarding the metal oxide nanoparticles (c), the average particle size of the primary particles is usually in the range of 1 nm to 500 nm, preferably 1 nm to 250 nm, more preferably about 1 nm to about 100 nm, even more preferably 1 nm to 50 nm, particularly preferably about 2 nm to about 30 nm, and most preferably 3 nm to 25 nm. Examples of methods for measuring the average particle size of the primary particles include a method using a transmission electron microscope (TEM) and a method calculating the average particle size from the specific surface area determined by the BET method.

[0148] Various methods for measuring average particle size using TEM are known, and one example is a method based on the equivalent circle diameter. This method involves processing projected images of particles obtained using a TEM (e.g., a transmission electron microscope HT7700 (manufactured by Hitachi High-Technologies Corporation)) with image processing software to determine the equivalent circle diameter of each particle, and then calculating the number average of these equivalent circle diameters to determine the average particle size. The equivalent circle diameter, also known as the Heywood diameter, is the diameter of a circle with the same area as the projected image of the particle. In this method, the projected images are typically processed using image processing software provided with the TEM and created by the TEM manufacturer.

[0149] The metal oxide nanoparticles (b) may comprise one or more organic capping groups. The organic capping groups may be reactive or non-reactive. Examples of reactive organic capping groups include organic capping groups that can be crosslinked by ultraviolet light or a radical initiator. In one embodiment, the metal oxide nanoparticles (b) comprise one or more organic capping groups.

[0150] The metal oxide nanoparticles (b) may contain one or more organic capping groups, but from the viewpoint of compatibility with the organic solvent of the present invention, metal oxide nanoparticles that are not organically capped, i.e., not surface-treated, are preferred.

[0151] Metal oxide nanoparticles (b) can be produced by known methods, but are also commercially available. Commercially available metal oxide nanoparticles are usually in the form of a dispersion. Preferably, a commercially available non-aqueous dispersion of metal oxide nanoparticles is used. Examples of suitable commercially available metal oxide nanoparticles include ORGANOSILICASOL™ (manufactured by Nissan Chemical Industries, Ltd.), which is a non-aqueous dispersion of SiO nanoparticles in various solvents (e.g., methanol, methyl ethyl ketone, methyl isobutyl ketone, N,N-dimethylacetamide, ethylene glycol, isopropanol, methanol, ethylene glycol monopropyl ether, cyclohexanone, ethyl acetate, toluene, and propylene glycol monomethyl ether acetate).

[0152] The content of metal oxide nanoparticles (b) in the ink composition of the present invention is expressed as a weight percentage relative to the total weight of the metal oxide nanoparticles (b) and the charge-transporting material (a) (including doped and undoped nanoparticles). The content of metal oxide nanoparticles (b) is typically about 1 wt% to about 98 wt%, preferably about 2 wt% to about 95 wt%, more preferably about 5 wt% to about 90 wt%, and even more preferably about 10 wt% to about 90 wt%, relative to the total weight of the metal oxide nanoparticles (b) and the charge-transporting material (a). In one embodiment, the content of metal oxide nanoparticles (b) is about 20 wt% to about 98 wt%, preferably about 25 wt% to about 95 wt%, relative to the total weight of the metal oxide nanoparticles (c) and the charge-transporting material (a).

[0153] The ink composition of the present invention contains a liquid carrier (c) having a predetermined composition. The composition of the liquid carrier (c) is important in the present invention. This composition will be described in more detail below.

[0154] As mentioned above, when forming a charge-transporting thin film by applying an ink composition to a substrate by inkjet printing, even if a substrate with a liquid-repellent bank is used as the substrate, the resulting charge-transporting thin film may have an uneven thickness due to the pile-up phenomenon. The present inventors have confirmed that this pile-up phenomenon is particularly likely to occur in ink compositions containing metal oxide nanoparticles. Although the cause is not clear, it is thought that the pile-up phenomenon occurs because metal oxide nanoparticles dispersed in the ink composition migrate to the side of the bank during the drying process and then creep up along the bank as a result of some kind of interaction with other components in the composition, the surface of the substrate, or the side of the bank.

[0155] Therefore, the present inventors have investigated the relationship between the behavior of metal oxide nanoparticles in an ink composition and the pile-up phenomenon, and as a result, have found that the more uniform the dispersion state of metal oxide nanoparticles in an ink composition, the more pronounced the pile-up phenomenon tends to occur, i.e., there is a correlation between the dispersion state of metal oxide nanoparticles in an ink composition and the occurrence of the pile-up phenomenon. This suggests that the pile-up phenomenon can be suppressed by appropriately controlling this dispersion state.

[0156] The dispersion state of metal oxide nanoparticles in the ink composition is affected by the composition of the liquid carrier used. Therefore, it was presumed that by specifying the composition of the liquid carrier, this dispersion state can be appropriately controlled, particularly during the process of volatilizing the liquid carrier, and the pile-up phenomenon can be suppressed.

[0157] Organic solvents can be classified into solvents with high compatibility (hereinafter referred to as "high compatibility solvents") and solvents with low compatibility (hereinafter referred to as "low compatibility solvents") based on the relative degree of compatibility with metal oxide nanoparticles. In a high compatibility solvent, metal oxide nanoparticles are uniformly dispersed throughout the solvent, whereas in a low compatibility solvent, they are in a heterogeneous dispersion state with a degree of aggregation depending on the compatibility with the metal oxide nanoparticles. In a mixture of a high compatibility solvent and a low compatibility solvent, the dispersion state is intermediate and varies depending on the ratio of the high compatibility solvent to the low compatibility solvent in the solvent.

[0158] On the other hand, when an ink composition containing a liquid carrier consisting of a mixture of multiple solvents is applied to a substrate and the liquid carrier evaporates, the solvent with a lower boiling point naturally evaporates first. Therefore, as the evaporation progresses, the composition of the liquid carrier remaining in the liquid state changes. If the liquid carrier contains a highly compatible solvent and a poorly compatible solvent, the ratio of these solvents in the remaining liquid carrier changes during the evaporation process, and the dispersion state of the metal oxide nanoparticles also changes accordingly. Therefore, by selecting a combination of solvents with appropriate boiling points and compatibility with the metal oxide nanoparticles and appropriately controlling the composition of the remaining liquid carrier, the dispersion state of the metal oxide nanoparticles in the liquid carrier can be controlled and the pile-up phenomenon can be suppressed.

[0159] If the low-compatibility solvent evaporates completely during the evaporation process and only the high-compatibility solvent remains until the end, the metal oxide nanoparticles will not aggregate until the final stage of the evaporation process and will be uniformly dispersed throughout the ink composition, making it easy to obtain a homogeneous charge-transporting thin film. However, if the above-mentioned film-forming method using a bank is adopted, the amount of metal oxide nanoparticles that migrate to the vicinity of the bank will be relatively large, making it more likely that a pile-up phenomenon will occur, making it difficult to obtain a flat charge-transporting thin film. On the other hand, if the highly compatible solvent evaporates first and only the poorly compatible solvent remains until the end, the dispersion state of the metal oxide nanoparticles becomes non-uniform in the final stage of the evaporation process, and the amount of metal oxide nanoparticles that migrate to the vicinity of the bank becomes relatively small, so the pile-up phenomenon is suppressed and it becomes easy to obtain a flat charge-transporting thin film. However, the metal oxide nanoparticles aggregate excessively, making it difficult to obtain a uniform charge-transporting thin film. Therefore, in order to properly form a charge-transporting thin film, it is preferable that the metal oxide nanoparticles are in an intermediate dispersion state, i.e., a dispersion state that is not completely uniform but involves a certain degree of aggregation, at the final stage of the liquid carrier evaporation process.

[0160] As a result of various investigations, the inventors have found that in order to suppress the pile-up phenomenon and enable film formation while ensuring flatness, it is effective to use a liquid carrier formed by combining a low-compatibility solvent with a first highly compatible solvent having a lower boiling point and a small amount of a second highly compatible solvent having a higher boiling point. As described above, it is preferable that the metal oxide nanoparticles are in a dispersed state with moderate aggregation, not completely uniform, at the final stage of the evaporation process of the liquid carrier. Such a dispersed state is achieved when the metal oxide nanoparticles are dispersed in a liquid carrier consisting of a poorly compatible solvent containing a small amount of a highly compatible solvent. When a liquid carrier with such a composition is used, most of the first highly compatible solvent evaporates first during the evaporation process of the liquid carrier, resulting in the remaining liquid carrier having a composition in which a small amount of the first highly compatible solvent is contained in a poorly compatible solvent together with a small amount of the second highly compatible solvent. This composition results in a preferable dispersed state of the metal oxide nanoparticles with moderate aggregation. As the evaporation progresses and all of the first highly compatible solvent evaporates, the second highly compatible solvent, which has a boiling point higher than that of the poorly compatible solvent, remains until the final stage of the evaporation process, maintaining a composition in which a small amount of the second highly compatible solvent is contained in a poorly compatible solvent until most of the poorly compatible solvent evaporates. As a result, the evaporation proceeds further, and the preferable dispersion state is maintained until the amount of the remaining liquid carrier becomes small enough to not cause the problem of pile-up.

[0161] Furthermore, as mentioned above, when an attempt is made to suppress the pile-up phenomenon without using a liquid carrier having the above-mentioned specific composition, certain characteristics of the organic EL device may tend to deteriorate. However, the present inventors have unexpectedly confirmed that when a charge-transporting thin film is formed using the ink composition of the present invention containing the above-mentioned liquid carrier and then used to produce an organic EL device, the deterioration in the characteristics of the resulting organic EL device is not so significant compared to when a conventional liquid carrier is used, and in particular, the deterioration in current efficiency is suppressed.

[0162] In this way, by using metal oxide nanoparticles in combination with a liquid carrier having a specific composition, it is possible to suppress the pile-up phenomenon while avoiding excessive deterioration of the characteristics of the organic EL device. As mentioned above, if the thickness of the charge transporting thin film becomes non-uniform due to the pile-up phenomenon, the life of the organic EL device may be shortened. However, by suppressing this pile-up phenomenon, the life of the organic EL device can be extended.

[0163] The liquid carrier used in the ink composition of the present invention is (c-1) Boiling point bp 1 a first hydrophilic glycol-based solvent having a viscosity of (°C); (c-2) Boiling point bp 2 a second hydrophilic glycol-based solvent having a temperature of (°C), and (c-3) Boiling point bp 3 (°C) The solvent (c-3) corresponds to the low compatibility solvent, the solvent (c-1) has a boiling point lower than that of the solvent (c-3) and corresponds to the first high compatibility solvent, and the solvent (c-2) has a boiling point higher than that of the solvent (c-3) and corresponds to the second high compatibility solvent. Therefore, the boiling point bp 1 , bp 2 and bp 3 is bp 1 <bp 3 <bp 2 From the viewpoint of process compatibility and film formation, 1 , bp 2 and bp 3are more preferably 180°C or higher, 270°C or higher, and 200°C or higher but lower than 270°C, respectively. In addition, within the range that satisfies the above conditions, bp 1 and bp 3 It is preferable that the difference between the temperature is 20°C or more, and the temperature 2 and bp 3 It is preferable that the difference between the temperature is 10℃ or more. 1 and bp 2 It is preferable that the difference between the temperatures is 70°C or more. 3 It is more preferable to use a combination of two types of the solvents (c-3) having a difference in temperature of 20° C. or more. In one embodiment, bp 1 is above 180°C, and bp 2 is above 270°C, and bp 3 is above 200°C and below 270°C.

[0164] As the solvents (c-1) and (c-2), hydrophilic glycol-based solvents are used. First, glycol-based solvents including these hydrophilic glycol-based solvents will be described. The term "glycol" is a general term for organic compounds having two alcoholic hydroxyl groups in a broad sense, but in the present invention, the term "glycol-based solvent" refers to a glycol-based solvent represented by the following formula (y): R 1 -O-(RO) n -R 2 (y) (In the formula, Each R is independently a linear, branched, or cyclic unsubstituted alkylene group having two or more carbon atoms; R 1 and R 2 each independently represents a hydrogen atom, a linear, branched, or cyclic unsubstituted alkyl group having one or more carbon atoms, or a linear or branched unsubstituted aliphatic acyl group having two or more carbon atoms; n is an integer equal to or greater than 1) The organic solvent has a chemical structure represented by the formula:

[0165] In the formula (y), each R is not particularly limited as long as it is a glycol-based solvent that is liquid under the conditions of use and can be finally evaporated. However, each R is preferably a linear C2-C4 unsubstituted alkylene group; 1 and R 2 is not particularly limited as long as it is a liquid under the conditions of use and provides a glycol-based solvent that can ultimately be evaporated, but each independently represents a hydrogen atom, a linear, branched, or cyclic C1-C8 unsubstituted alkyl group, or a linear or branched C1-C8 unsubstituted aliphatic acyl group; and n is preferably an integer of 1 to 6. R is particularly preferably a C2 or C3 unsubstituted alkylene group. Furthermore, n is particularly preferably an integer of 1 to 4. The alkyl group is preferably a linear, branched or cyclic C1-C6 unsubstituted alkyl group, more preferably a linear C1-C4 unsubstituted alkyl group, and particularly preferably a methyl group or an n-butyl group. The acyl group is preferably a linear or branched C2-C6 unsubstituted aliphatic acyl group, more preferably a linear C2-C4 unsubstituted acyl group, and particularly preferably an acetyl group or a propionyl group. An ink composition using a liquid carrier containing such a glycol-based solvent is particularly suitable for application by inkjet printing.

[0166] Among the glycol-based solvents, R 1 and R 2 In the present invention, an organic solvent having a chemical structure in which all of the groups are hydrogen atoms is referred to as a "glycol solvent." Examples of glycol solvents include, but are not limited to, ethylene glycol, propylene glycol, and oligomers thereof (dimers to tetramers, for example, diethylene glycol).

[0167] Among the glycol-based solvents, R 1 and R 2In the present invention, an organic solvent having a chemical structure in which one of the alkyl groups is a hydrogen atom and the other is an unsubstituted alkyl group is referred to as a "glycol monoether solvent." The glycol monoether solvent corresponds to the monoalkyl ether of the glycol solvent. Examples of glycol monoether solvents include ethylene glycol monopropyl ether, ethylene glycol monohexyl ether (hexyl cellosolve), propylene glycol monobutyl ether (Dowanol PnB), diethylene glycol monoethyl ether (ethyl carbitol), dipropylene glycol n-butyl ether (Dowanol DPnB), ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monobutyl ether (butyl carbitol), diethylene glycol monoisobutyl ether, dipropylene glycol monomethyl ether (Dowanol DPM), propylene glycol monopropyl ether (Dowanol PnP), diethylene glycol monopropyl ether (propyl carbitol), diethylene glycol monohexyl ether (hexyl carbitol), 2-ethylhexyl carbitol, dipropylene glycol monopropyl ether (Dowanol DPnP), tripropylene glycol monomethyl ether (Dowanol TPM), diethylene glycol monomethyl ether (methyl carbitol), and tripropylene glycol monobutyl ether (Dowanol TPnB), but are not limited to these.

[0168] Among the glycol-based solvents, R 1 and R 2 are unsubstituted alkyl groups is referred to in the present invention as a "glycol diether solvent." A glycol diether solvent corresponds to the dialkyl ether of the glycol solvent. Examples of glycol diether solvents include, but are not limited to, ethylene glycol diethers (such as 1,2-dimethoxyethane, 1,2-diethoxyethane, and 1,2-dibutoxyethane); diethylene glycol diethers (such as diethylene glycol dimethyl ether and diethylene glycol diethyl ether); propylene glycol diethers (such as propylene glycol dimethyl ether, propylene glycol diethyl ether, and propylene glycol dibutyl ether); dipropylene glycol diethers (such as dipropylene glycol methyl-n-propyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, and dipropylene glycol dibutyl ether); and the higher order analogs of the ethylene glycol and propylene glycol ethers mentioned herein (i.e., tri- and tetra analogs, e.g., triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether, and tetraethylene glycol dimethyl ether).

[0169] Among the glycol-based solvents, R 1 and R 2 In the present invention, an organic solvent having a chemical structure in which one of the groups is a hydrogen atom and the other is an unsubstituted aliphatic acyl group is referred to as a "glycol monoester solvent." The glycol monoester solvent corresponds to an aliphatic carboxylic acid monoester of the glycol solvent. Examples of glycol monoester solvents include, but are not limited to, ethylene glycol monoacetate, propylene glycol monoacetate, 1,4-butanediol monoacetate, 1,3-butylene glycol monoacetate, and higher glycol ether analogs (such as di-, tri-, and tetra-analogs, e.g., triethylene glycol monoacetate).

[0170] Among the glycol-based solvents, R 1 and R 2In the present invention, an organic solvent having a chemical structure in which all of the groups are unsubstituted aliphatic acyl groups is referred to as a “glycol diester solvent.” The glycol diester solvent corresponds to the aliphatic carboxylic acid diester of the glycol solvent. Examples of glycol diester solvents include, but are not limited to, ethylene glycol diacetate, propylene glycol diacetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, and higher glycol ether analogs (such as di-, tri-, and tetra analogs, e.g., triethylene glycol diacetate).

[0171] Among the glycol-based solvents, R 1 and R 2 In the present invention, an organic solvent having a chemical structure in which one of the alkyl groups is an unsubstituted alkyl group and the other is an unsubstituted aliphatic acyl group is referred to as a "glycol ester ether solvent." The glycol ester ether solvent corresponds to the aliphatic carboxylic acid monoester of the glycol monoether solvent. Examples of glycol ester ether solvents include, but are not limited to, ethylene glycol monoether acetates (e.g., ethylene glycol monomethyl ether acetate, 2-ethoxyethyl acetate, and 2-butoxyethyl acetate), propylene glycol monoether acetates (e.g., propylene glycol monomethyl ether acetate), and higher glycol ether analogs (such as di-, tri-, and tetra-analogs, e.g., diethylene glycol monomethyl ether acetate and dipropylene glycol monomethyl ether acetate).

[0172] The glycol-based solvents are classified into "hydrophilic glycol-based solvents" and "hydrophobic glycol-based solvents" based on their chemical structures. In the present invention, "hydrophilic glycol-based solvents" refers to the glycol solvents among the glycol-based solvents, and "hydrophobic glycol-based solvents" is a general term for the glycol monoether solvents, glycol diether solvents, glycol monoester solvents, glycol diester solvents, and glycol ester ether solvents.

[0173] Preferred examples of the hydrophilic glycol solvent (c-1) include, but are not limited to, glycol solvents having a low molecular weight and a low boiling point, such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol. From the viewpoints of process compatibility and film-forming properties, ethylene glycol is particularly preferred.

[0174] Preferred examples of the solvent (c-2), which is also a hydrophilic glycol solvent, include glycol solvents having a higher molecular weight and boiling point than the solvent (c-1), such as triethylene glycol, tripropylene glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol, etc., but are not limited to these. From the viewpoints of process compatibility and film-forming properties, triethylene glycol is particularly preferred. In one embodiment, the solvent (c-1) is ethylene glycol and the solvent (c-2) is triethylene glycol.

[0175] On the other hand, the organic solvent used as the solvent (c-3) is bp 1 <bp 3 <bp 2 The solvent (c-3) may be a mixed solvent containing two or more organic solvents. In this case, the two or more organic solvents may all be bp 1 <bp 3 <bp 2 Satisfy the relationship.

[0176] In one embodiment, the solvent (c-3) is a hydrophobic glycol-based solvent, a nitrile, an alcohol, an aromatic ether, an aromatic ester, or an aromatic hydrocarbon. From the viewpoints of process compatibility and film-forming properties, it is preferable to use the hydrophobic glycol-based solvent, i.e., a glycol monoether solvent, a glycol diether solvent, a glycol monoester solvent, a glycol diester solvent, and / or a glycol ester ether solvent, as the solvent (c-3). In one embodiment, the solvents (c-1) and (c-2) are both glycol solvents, and the solvent (c-3) is a glycol diether solvent.

[0177] From the viewpoint of film-forming properties, the solvent (c-3) is more preferably a mixed solvent. This mixed solvent preferably contains two or more glycol monoether solvents or glycol diether solvents, and particularly preferably contains at least one glycol monoether to improve solution uniformity. Among them, a combination of diethylene glycol butyl methyl ether and diethylene glycol monobutyl ether or diethylene glycol butyl methyl ether and diethylene glycol monoisobutyl ether is preferred, and a combination of diethylene glycol butyl methyl ether and diethylene glycol monobutyl ether is most preferred. In one embodiment, the solvent (c-3) is a mixture of two or more organic solvents containing one or more glycol diether solvents.

[0178] The liquid carrier (c) may contain a non-glycol-based solvent, that is, an organic solvent other than the glycol-based solvent. Examples of non-glycol solvents include, but are not limited to, aromatic esters, aliphatic and aromatic ketones, organic sulfur solvents (such as dimethyl sulfoxide (DMSO) and 2,3,4,5-tetrahydrothiophene-1,1-dioxide (tetramethylene sulfone; sulfolane)), tetrahydrofuran (THF), tetrahydropyran (THP), tetramethylurea (TMU), N,N'-dimethylpropylene urea, alkylated benzenes (such as xylene and its isomers), halogenated benzenes, N-methylpyrrolidinone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dichloromethane, acetonitrile, dioxanes, ethyl acetate, ethyl benzoate, methyl benzoate, dimethyl carbonate, ethylene carbonate, propylene carbonate, 3-methoxypropionitrile, 3-ethoxypropionitrile, diethyl fumarate, butyl benzoate, propylene carbonate, or combinations thereof. Of these, diethyl fumarate, butyl benzoate and propylene carbonate are preferred from the viewpoint of film-forming properties.

[0179] Aliphatic and aromatic ketones include, but are not limited to, acetone, acetonylacetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, methyl isobutenyl ketone, 2-hexanone, 2-pentanone, acetophenone, ethyl phenyl ketone, cyclohexanone, and cyclopentanone. In some embodiments, ketones with a proton on the carbon alpha to the ketone, such as cyclohexanone, methyl ethyl ketone, and acetone, are avoided.

[0180] Other organic solvents that fully or partially solubilize or swell the charge transport material are also contemplated, and may be included in the liquid carrier in varying amounts to adjust ink properties such as wetting, viscosity, and morphology control.

[0181] Still other organic solvents suitable for use in accordance with the present invention include ethers such as anisole, ethoxybenzene, dimethoxybenzene.

[0182] Furthermore, as alcohols, aliphatic alcohols such as methanol, ethanol, trifluoroethanol, n-propanol, isopropanol, n-butanol, and t-butanol, benzyl alcohol, and 2-(benzyloxy)ethanol, as aromatic ethers, methyl anisole, dimethyl anisole, ethyl anisole, butylphenyl ether, butyl anisole, pentyl anisole, hexyl anisole, heptyl anisole, octyl anisole, and phenoxytoluene, as aromatic hydrocarbons, pentylbenzene, hexylbenzene, heptylbenzene, octylbenzene, nonylbenzene, cyclohexylbenzene, and tetralin, etc., can also be used.

[0183] As disclosed herein, the organic solvents disclosed herein can be used in various proportions in the liquid carrier to improve ink properties such as substrate wetting, ease of solvent removal, viscosity, surface tension, and jettability.

[0184] In some embodiments, the use of aprotic non-polar solvents can provide the added benefit of extending the lifetime of devices with emitter technology that is sensitive to protons (eg, PHOLEDs, etc.).

[0185] In some embodiments, the liquid carrier comprises dimethyl sulfoxide, tetramethylurea, or a mixture thereof.

[0186] As mentioned above, in order to form a flat thin film while suppressing the pile-up phenomenon, it is important that the solvent (c-2) contains small amounts of the solvents (c-1) and (c-3) after most of the solvent (c-1) has evaporated during the evaporation process of the liquid carrier. To achieve this, it is preferable that the ratio of the amounts of the solvents (c-1), (c-2), and (c-3) is appropriate. From this perspective, the weight ratio of the solvent (c-1) to the solvent (c-2) ((c-1):(c-2)) is preferably 29:1 to 8:7, more preferably 9:1 to 3:7, and most preferably 5:1 to 23:7. The weight ratio of the solvent (c-1) to the total weight of the liquid carrier (c) is preferably 16 to 29%, more preferably 16 to 27%, even more preferably 20 to 25%, and most preferably 23 to 25%. The weight ratio of the solvent (c-2) to the total weight of the liquid carrier (c) is preferably 14 to 1%, more preferably 14 to 3%, even more preferably 10 to 5%, and most preferably 7 to 5%. The weight ratios of the solvents (c-1), (c-2), and (c-3) to the total weight of the liquid carrier (c) are most preferably 23 to 25%, 7 to 5%, and 70%, respectively.

[0187] The amount of the liquid carrier in the ink composition of the present invention is about 50% by weight to about 99% by weight, typically about 75% by weight to about 98% by weight, and more typically about 90% by weight to about 95% by weight, based on the total amount of the ink composition.

[0188] As will be described later, the ink composition of the present invention can be prepared by mixing the components, such as the charge transport material, in the form of a solution or dispersion (stock solution) in an organic solvent. The organic solvent added to the ink composition as a result of this operation is considered to be part of the liquid carrier.

[0189] The liquid carrier may also be adapted for use and processing with other layers in the device, such as the anode or light-emitting layer.

[0190] In one embodiment, the ink composition of the present invention further comprises one or more amine compounds. Amine compounds suitable for use in the ink compositions of the present invention include, but are not limited to, ethanolamines and alkylamines.

[0191] Examples of suitable ethanolamines include dimethylethanolamine [(CH3)2NCH2CH2OH], triethanolamine [N(CH2CH2OH)3], and N-tert-butyldiethanolamine [t-C4H9N(CH2CH2OH)2].

[0192] Alkylamines include primary, secondary, and tertiary alkylamines. Examples of primary alkylamines include, for example, ethylamine [C2H5NH2], n-butylamine [C4H9NH2], t-butylamine [C4H9NH2], n-hexylamine [C6H 13 NH2], 2-ethylhexylamine [C8H 17 NH2], n-decylamine [C 10 H 21 NH], and ethylenediamine [HNCHCHNH]. Secondary alkylamines include, for example, diethylamine [(C2H5)2NH], di(n-propylamine) [(n-C3H9)2NH], di(isopropylamine) [(i-C3H9)2NH], and dimethylethylenediamine [CH3NHCH2CH2NHCH3]. Tertiary alkylamines include, for example, trimethylamine [(CH3)3N], triethylamine [(C2H5)3N], tri(n-butyl)amine [(C4H9)3N], and tetramethylethylenediamine [(CH3)2NCH2CH2N(CH3)2].

[0193] In some embodiments, the amine compound is a tertiary alkylamine. In some embodiments, the amine compound is triethylamine.

[0194] In some embodiments, the amine compound is a mixture of a tertiary alkylamine compound and an amine compound other than a tertiary alkylamine compound.In some embodiments, the amine compound other than a tertiary alkylamine compound is a primary alkylamine compound.In some embodiments, the primary alkylamine compound is at least one selected from the group consisting of ethylamine, n-butylamine, t-butylamine, n-hexylamine, 2-ethylhexylamine, n-decylamine and ethylenediamine, and among these, 2-ethylhexylamine or n-butylamine is preferred.

[0195] The amount of the amine compound can be adjusted and measured as a weight percentage relative to the total amount of the ink composition. In some embodiments, the amount of the amine compound is at least 0.01 wt %, at least 0.10 wt %, at least 1.00 wt %, at least 1.50 wt %, or at least 2.00 wt %, relative to the total amount of the ink composition. In some embodiments, the amount of the amine compound is from about 0.01 to about 2.00 wt %, typically from about 0.05 wt % to about 1.50 wt %, and more typically from about 0.1 wt % to about 1.0 wt %, relative to the total amount of the ink composition. At least a portion of the amine compound may be present in the form of an ammonium salt with the sulfonated conjugated polymer, such as a trialkylammonium salt (sulfonated polythiophene amine adduct).

[0196] Although this amine compound is usually added when preparing the final ink composition, it may also be added in advance at an earlier stage. For example, as described above, an amine compound may be added to a sulfonated conjugated polymer to convert it into a corresponding ammonium salt, such as a trialkylammonium salt (sulfonated polythiophene amine adduct), and then the resulting polymer may be subjected to a reduction treatment. Alternatively, an amine compound (e.g., triethylamine) may be added to a solution of the reduced sulfonated conjugated polymer to precipitate the sulfonated conjugated polymer as an ammonium salt (e.g., triethylammonium salt) in the form of a powder, which may then be recovered. There are no particular limitations on the method of such treatment, but for example, a method can be employed in which water and triethylamine are added to the reduced sulfonated polythiophene to dissolve it, the solution is stirred under heating (e.g., 60°C), isopropyl alcohol and acetone are added to the resulting solution to cause a precipitate of the triethylammonium salt of the sulfonated conjugated polymer, and the precipitate is collected by filtration.

[0197] The ink compositions of the present invention may optionally further comprise one or more matrix compounds known to be useful in hole injection layers (HILs) or hole transport layers (HTLs).

[0198] The optional matrix compound may be a low-molecular-weight or high-molecular-weight compound and may be different from the polythiophenes described herein. The matrix compound may be, for example, a synthetic polymer different from polythiophenes. See, for example, U.S. Patent Publication No. 2006 / 0175582, published August 10, 2006. The synthetic polymer may, for example, comprise a carbon backbone. In some embodiments, the synthetic polymer has at least one polymeric side group comprising an oxygen atom or a nitrogen atom. The synthetic polymer may be a Lewis base. Typically, the synthetic polymer comprises a carbon backbone and has a glass transition temperature greater than 25°C. The synthetic polymer may also be a semi-crystalline or crystalline polymer having a glass transition temperature of 25°C or less and / or a melting point greater than 25°C. The synthetic polymer may also comprise one or more acidic groups, such as sulfonic acid groups. In some embodiments, the ink composition of the present invention further comprises a synthetic polymer containing one or more acidic groups.

[0199] In some embodiments, the synthetic polymer is a polymeric acid comprising one or more repeating units containing at least one alkyl or alkoxy group substituted with at least one fluorine atom and at least one sulfonic acid (—SOH) residue, optionally interrupted by at least one ether linkage (—O—) group.

[0200] In some embodiments, the polymeric acid comprises a repeat unit according to formula (II) and a repeat unit according to formula (III):

[0201] [ka] [Wherein, each of R5, R6, R7, R8, R9, R 10 , and R 11 are independently H, halogen, fluoroalkyl, or perfluoroalkyl; and X is —[OC(R h R i )-C(R j R k )] q -O-[CR l R m ] z -SO3H, where each R h , R i , R j , R k , R l and R m are independently H, halogen, fluoroalkyl, or perfluoroalkyl; q is 0-10; and z is 1-5.

[0202] In some embodiments, each of R5, R6, R7, and R8 is independently Cl or F. In some embodiments, each of R5, R7, and R8 is F and R6 is Cl. In some embodiments, each of R5, R6, R7, and R8 is F.

[0203] In some embodiments, each of R, R 10 and R 11 is F.

[0204] In certain embodiments, each R h , R i , R j , R k , R l and R mis independently F, (C1-C8)fluoroalkyl, or (C1-C8)perfluoroalkyl.

[0205] In certain embodiments, each R l and R m is F; q is 0; and z is 2.

[0206] In certain embodiments, each of R5, R7, and R8 is F, R6 is Cl; and each R l and R m is F; q is 0; and z is 2.

[0207] In certain embodiments, each of R, R, R, and R is F; l and R m is F; q is 0; and z is 2.

[0208] The ratio of the number of repeating units according to Formula (II) ("n") to the number of repeating units according to Formula (III) ("m") is not particularly limited. The n:m ratio is typically 9:1 to 1:9, more typically 8:2 to 2:8. In some embodiments, the n:m ratio is 9:1. In some embodiments, the n:m ratio is 8:2.

[0209] Polymeric acids suitable for use in the present invention can be synthesized using methods known to those skilled in the art or obtained from commercial sources. For example, a polymer comprising a repeating unit according to formula (II) and a repeating unit according to formula (III) can be prepared by converting a monomer represented by formula (IIa) to a monomer represented by formula (IIIa):

[0210] [ka] [Wherein Z1 is —[OC(R h R i )-C(R j R k )] q -O-[CR l R m ]z -SO2F, where R h , R i , R j , R k , R l and R m , q, and z have the same meanings as in the present specification] by a known polymerization method, followed by conversion of the sulfonyl fluoride group to a sulfonic acid group by hydrolysis.

[0211] For example, tetrafluoroethylene (TFE) or chlorotrifluoroethylene (CTFE) may be prepared by reacting one or more fluorinated monomers containing precursor groups of sulfonic acid (e.g., F2C=CF-O-CF2-CF2-SO2F; F2C=CF-[O-CF2-CR 12 FO] q -CF2-CF2-SO2F (where R 12 is F or CF3, and q is 1 to 10); F2C=CF-O-CF2-CF2-CF2-SO2F; and F2C=CF-OCF2-CF2-CF2-CF2-SO2F, etc.

[0212] The equivalent weight of a polymeric acid is defined as the mass (grams) of polymeric acid per mole of acid groups present in the polymeric acid. The equivalent weight of a polymeric acid is from about 400 to about 15,000 g polymer / mol acid, typically from about 500 to about 10,000 g polymer / mol acid, more typically from about 500 to 8,000 g polymer / mol acid, even more typically from about 500 to 2,000 g polymer / mol acid, and even more typically from about 600 to about 1,700 g polymer / mol acid.

[0213] Such polymeric acids are, for example, those sold under the trade name NAFION® by EI DuPont, those sold under the trade name AQUIVION® by Solvay Specialty Polymers, or those sold under the trade name FLEMION® by Asahi Glass Co.

[0214] In some embodiments, the synthetic polymer is a polyethersulfone that includes one or more repeat units that contain at least one sulfonic acid (—SO 3 H) residue.

[0215] In some embodiments, the polyethersulfone has formula (IV):

[0216] [ka] as well as repeating units according to formula (V) and repeating units according to formula (VI):

[0217] [ka] [In the formula, R 12 ~R 20 are each independently H, halogen, alkyl, or SO3H, with the proviso that R 12 ~R 20 at least one of is SO3H; and R 21 ~R 28 are each independently H, halogen, alkyl, or SO3H, with the proviso that R 21 ~R 28 At least one of is SO3H, and R 29 and R 30 are each H or alkyl.

[0218] In some embodiments, R 29 and R 30 and R are each alkyl. 29 and R 30 are methyl, respectively.

[0219] In some embodiments, R 12 ~R 17 , R 19 , and R 20 are H and R, respectively. 18 is SO3H.

[0220] In some embodiments, R 21 ~R 25 , R 27 , and R 28 are H and R, respectively. 26 is SO3H.

[0221] In some embodiments, the polyethersulfone has formula (VII):

[0222] [ka] [wherein a is 0.7 to 0.9, and b is 0.1 to 0.3].

[0223] The polyethersulfone may further comprise other repeating units, which may or may not be sulfonated.

[0224] For example, polyethersulfone may be represented by the formula (VIII):

[0225] [ka] [In the formula, R 31 and R 32 are each independently H or alkyl.

[0226] Any two or more repeat units described herein can be combined to form a repeat unit, and polyethersulfones may include such repeat units. For example, a repeat unit according to formula (IV) can be combined with a repeat unit according to formula (VI) to form a repeat unit according to formula (IX):

[0227] [ka] It is possible to provide a repeating unit according to the following formula:

[0228] Similarly, for example, a repeat unit according to formula (IV) can be combined with a repeat unit according to formula (VIII) to form a repeat unit according to formula (X):

[0229] [ka] It is possible to provide a repeating unit according to the following formula:

[0230] In some embodiments, the polyethersulfone has formula (XI):

[0231] [ka] [wherein a is 0.7 to 0.9, and b is 0.1 to 0.3].

[0232] Polyethersulfones containing one or more repeat units containing at least one sulfonic acid (—SO3H) residue are commercially available; for example, sulfonated polyethersulfone is sold as S-PES by Konishi Chemical Ind. Co., Ltd.

[0233] The optional matrix compound may be a planarizing agent. The matrix compound or planarizing agent may be, for example, a polymer or oligomer such as an organic polymer (e.g., poly(styrene) or a poly(styrene) derivative; poly(vinyl acetate) or a derivative thereof; poly(ethylene glycol) or a derivative thereof; poly(ethylene-co-vinyl acetate); poly(pyrrolidone) or a derivative thereof (e.g., poly(1-vinylpyrrolidone-co-vinyl acetate)); poly(vinylpyridine) or a derivative thereof; poly(methyl methacrylate) or a derivative thereof; poly(butyl acrylate); poly(aryl ether ketone); poly(arylsulfone); poly(ester) or a derivative thereof; or a combination thereof).

[0234] In certain embodiments, the matrix compound is poly(styrene) or a poly(styrene) derivative.

[0235] In one embodiment, the matrix compound is poly(4-hydroxystyrene).

[0236] The optional matrix compound or planarizing agent may, for example, comprise at least one semiconducting matrix component. This semiconducting matrix component is different from the polythiophenes described herein. The semiconducting matrix component may be a semiconducting small molecule or semiconducting polymer, typically consisting of repeating units containing hole-transporting units in the main chain and / or side chains. The semiconducting matrix component may be neutral or doped and is typically soluble and / or dispersible in organic solvents (e.g., toluene, chloroform, acetonitrile, cyclohexanone, anisole, chlorobenzene, o-dichlorobenzene, ethyl benzoate, and mixtures thereof).

[0237] The amount of optional matrix compound can be adjusted and measured as a weight percentage relative to the amount of doped or undoped polythiophene. In some embodiments, the amount of optional matrix compound is 0 to about 99.5 wt %, typically about 10 wt % to about 98 wt %, more typically about 20 wt % to about 95 wt %, and even more typically about 25 wt % to about 45 wt %, relative to the amount of doped or undoped polythiophene. In 0 wt % embodiments, the ink composition is free of matrix compound.

[0238] In some embodiments, the polythiophene comprising a repeating unit according to formula (I) is doped with a dopant. Dopants are known in the art. For example, see U.S. Patent No. 7,070,867; U.S. Publication No. 2005 / 0123793; and U.S. Publication No. 2004 / 0113127. The dopant may be an ionic compound. The dopant may include cations and anions. One or more dopants may be used to dope the polythiophene comprising a repeating unit according to formula (I).

[0239] The cation of the ionic compound can be, for example, V, Cr, Mn, Fe, Co, Ni, Cu, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Ta, W, Re, Os, Ir, Pt, or Au.

[0240] The cations of the ionic compounds can be, for example, gold, molybdenum, rhenium, iron, and silver cations.

[0241] In some embodiments, the dopant may comprise a sulfonate or carboxylate, including alkyl, aryl, and heteroaryl sulfonates or carboxylates. As used herein, "sulfonate" refers to a -SO3M group (where M is H). + or alkali metal ions (e.g., Na + , Li + , K. + , Rb + , Cs + etc.); or ammonium (NH4 + As used herein, "carboxylate" refers to a -COM group, where M is H + or alkali metal ions (e.g., Na + , Li + , K. + , Rb + , Cs + etc.); or ammonium (NH4 +Examples of sulfonate and carboxylate dopants include, but are not limited to, benzoate compounds, heptafluorobutyrate, methanesulfonate, trifluoromethanesulfonate, p-toluenesulfonate, pentafluoropropionate, and polymeric sulfonates, perfluorosulfonate-containing ionomers, and the like.

[0242] In some embodiments, the dopant does not include a sulfonate or a carboxylate.

[0243] In some embodiments, the dopant may include sulfonylimides (e.g., bis(trifluoromethanesulfonyl)imides, etc.); antimonates (e.g., hexafluoroantimonates, etc.); arsenates (e.g., hexafluoroarsenates, etc.); phosphorus compounds (e.g., hexafluorophosphates, etc.); and borates (e.g., tetrafluoroborate, tetraarylborates, and trifluoroborates, etc.). Examples of tetraarylborates include, but are not limited to, halogenated tetraarylborates such as tetrakispentafluorophenylborate (TPFB). Examples of trifluoroborates include, but are not limited to, (2-nitrophenyl)trifluoroborate, benzofurazan-5-trifluoroborate, pyrimidine-5-trifluoroborate, pyridine-3-trifluoroborate, and 2,5-dimethylthiophene-3-trifluoroborate.

[0244] The dopant can be, for example, a material that undergoes one or more electron transfer reactions with the conjugated polymer to form a doped polythiophene. The dopant can be selected to provide an appropriate charge-balancing counteranion. The reaction can occur by mixing the polythiophene with the dopant, as is known in the art. For example, the dopant can undergo spontaneous electron transfer from the polymer to a cation-anion dopant (e.g., a metal salt), leaving the conjugated polymer in its oxidized form with an associated anion and free metal. See, for example, Lebedev et al., Chem. Mater., 1998, 10, 156-163. As disclosed herein, polythiophene and dopant can refer to components that react to form a doped polymer. The doping reaction can be a charge transfer reaction in which charge carriers are generated, and the reaction can be reversible or irreversible. In some embodiments, silver ions can undergo electron transfer to or from silver metal and the doped polymer.

[0245] In the final formulation, the composition may be distinct from the original combination of components (i.e., the polythiophene and / or dopant may or may not be present in the final composition in the same form as before mixing). As the dopant, an inorganic acid, an organic acid, an organic or inorganic oxidizing agent, or the like is used. As the organic acid, a polymer organic acid and / or a low molecular weight organic acid (non-polymer organic acid) is used. In one embodiment, the organic acid is a sulfonic acid and its salt (-SOM, where M is an alkali metal ion (e.g., Na + , Li + , K. + , Rb + , Cs + etc.), ammonium (NH4 + ), mono-, di-, and trialkylammonium (such as triethylammonium). Among the sulfonic acids, arylsulfonic acids are preferred.

[0246] In some embodiments, specific examples of dopants include strong inorganic acids such as hydrogen chloride, sulfuric acid, nitric acid, and phosphoric acid; Lewis acids such as aluminum(III) chloride (AlCl), titanium(IV) tetrachloride (TiCl), boron tribromide (BBr), boron trifluoride etherate (BF·OEt), iron(III) chloride (FeCl), copper(II) chloride (CuCl), antimony(V) pentachloride (SbCl), arsenic(V) pentafluoride (AsF), phosphorus pentafluoride (PF), and tris(4-bromophenyl)aluminum hexachloroantimonate (TBPAH); polymeric organic acids such as polystyrene sulfonic acid; benzenesulfonic acid, tosylic acid, camphorsulfonic acid, and arsenic trichloride (BF·OEt). Examples of oxidizing agents include, but are not limited to, low-molecular-weight organic acids (non-polymer organic acids) such as hydroxybenzenesulfonic acid, 5-sulfosalicylic acid, dodecylbenzenesulfonic acid, 1,4-benzodioxanedisulfonic acid derivatives described in WO 2005 / 000832, arylsulfonic acid derivatives described in WO 2006 / 025342, and dinonylnaphthalenesulfonic acid derivatives described in JP 2005-108828 A; and organic or inorganic oxidizing agents such as 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), iodine, and heteropolyacid compounds. In a preferred embodiment, from the viewpoint of reproducibly obtaining a charge-transporting thin film that has excellent flatness and provides excellent life characteristics when applied to an OLED, the aryl sulfonic acid contained in the polymer composition of the present invention does not include polystyrene sulfonic acid (PSS).

[0247] In some embodiments, the dopant comprises at least one selected from the group consisting of an arylsulfonic acid compound, a heteropolyacid compound, and an ionic compound containing an element belonging to Group 13 or 15 of the long form periodic table. Particularly preferred dopants include polymeric organic acids such as polystyrene sulfonic acid, 5-sulfosalicylic acid, dodecylbenzenesulfonic acid, 1,4-benzodioxanedisulfonic acid derivatives described in WO 2005 / 000832, and low-molecular-weight organic acids (non-polymeric organic acids) such as dinonylnaphthalenesulfonic acid derivatives described in JP 2005-108828 A. In addition, sulfonic acid derivatives represented by the following formula (2) can also be suitably used.

[0248] [ka] [In the formula, X represents O, S, or NH; A represents a naphthalene ring or an anthracene ring which may have substituents other than X and n (SOH) groups; B represents an unsubstituted or substituted hydrocarbon group, a 1,3,5-triazine group, or an unsubstituted or substituted group represented by the following formula (3) or (4): [ka] (wherein W 1 and W 2 each independently represents O, S, an S(O) group, an S(O2) group, or an unsubstituted or substituted N, Si, P, or P(O) group. 1 R may be a single bond. 46 ~R 59 each independently represents a hydrogen atom or a halogen atom; n represents the number of sulfonic acid groups bonded to A and is an integer satisfying 1≦n≦4; and q represents the number of bonds between B and X and is an integer satisfying 1≦q.

[0249] R in equation (3) or (4) 46 ~R 59 is preferably a fluorine atom, and more preferably all of them are fluorine atoms. 1 is preferably a single bond. Most preferably, W in formula (3) is 1 is a single bond, and R 46 ~R 53are all fluorine atoms.

[0250] The arylsulfonic acid compound according to the present invention may further be one represented by the following formula (6). [ka] (wherein X represents O, S or NH; Ar 5 represents an aryl group, and n represents the number of sulfone groups and is an integer of 1 to 4.

[0251] In the formula (6), X represents O, S or NH, with O being particularly preferred due to ease of synthesis. n represents the number of sulfone groups bonded to the naphthalene ring and is an integer between 1 and 4, but considering that the compound has high electron accepting ability and high solubility, n is preferably 1 or 2. Among these, a compound represented by the following formula (7) is suitable. [ka] (In the formula, Ar 5 represents an aryl group.

[0252] Examples of the aryl group in formula (6) and formula (7) include aryl groups such as a phenyl group, a xylyl group, a tolyl group, a biphenyl group, and a naphthyl group, and these aryl groups may have a substituent. Examples of the substituent include, but are not limited to, a hydroxyl group, an amino group, a silanol group, a thiol group, a carboxyl group, a phosphoric acid group, a phosphoric acid ester group, an ester group, a thioester group, an amide group, a nitro group, a cyano group, a monovalent hydrocarbon group, an organooxy group, an organoamino group, an organosilyl group, an organothio group, an acyl group, a sulfone group, and a halogen atom. Among these aryl groups, the aryl group represented by the following formula (8) is particularly preferably used. [ka] (In the formula, R 60 ~R 64 are each independently a hydrogen atom, a halogen atom, a nitro group, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or a halogenated alkenyl group having 2 to 10 carbon atoms.

[0253] In formula (8), the halogen atom may be any of chlorine, bromine, fluorine and iodine atoms, but in the present invention, a fluorine atom is particularly preferred. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, a 2-ethylhexyl group, an n-decyl group, a cyclopentyl group, and a cyclohexyl group. Examples of halogenated alkyl groups having 1 to 10 carbon atoms include a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2,2-pentafluoroethyl group, a 3,3,3-trifluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a 1,1,2,2,3,3,3-heptafluoropropyl group, a 4,4,4-trifluorobutyl group, a 3,3,4,4,4-pentafluorobutyl group, a 2,2,3,3,4,4,4-heptafluorobutyl group, and a 1,1,2,2,3,3,4,4,4-nonafluorobutyl group. Examples of the halogenated alkenyl group having 2 to 10 carbon atoms include a perfluorovinyl group, a perfluoropropenyl group (allyl group), and a perfluorobutenyl group. Among these, in consideration of further increasing the solubility in organic solvents, it is particularly preferable to use an aryl group represented by the following formula (9). [ka] (In the formula, R 62 represents a hydrogen atom, a halogen atom, a nitro group, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or a halogenated alkenyl group having 2 to 10 carbon atoms.

[0254] In formula (9), R 62 In particular, a halogenated alkyl group, a halogenated alkynyl group, and a nitro group are preferred, and a trifluoromethyl group, a perfluoropropenyl group, and a nitro group are more preferred.

[0255] Furthermore, the following formula (5a) or Z 1 Ionic compounds comprising an anion represented by the following formula and its counter cation can also be suitably used as dopants. [ka] (wherein E represents an element belonging to Group 13 or 15 of the long period periodic table, and Ar 1 ~Ar 4 each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent.

[0256] In formula (5a), E is preferably boron, gallium, phosphorus, or antimony among elements belonging to Group 13 or 15 of the long-form periodic table, and more preferably boron.

[0257] In formula (5a), examples of the aromatic hydrocarbon group and aromatic heterocyclic group include monovalent groups derived from a 5- or 6-membered monocycle or 2- to 4-condensed ring. Among these, from the viewpoints of the stability and heat resistance of the compound, monovalent groups derived from a benzene ring, naphthalene ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, and isoquinoline ring are preferred. Furthermore, Ar 1 ~Ar 4 It is more preferable that at least one of the groups has one or more fluorine atoms or chlorine atoms as a substituent. 1 ~Ar 4 It is most preferably a perfluoroaryl group in which all of the hydrogen atoms in the above group are substituted with fluorine atoms. Specific examples of the perfluoroaryl group include a pentafluorophenyl group, a heptafluoro-2-naphthyl group, and a tetrafluoro-4-pyridyl group.

[0258] Z 1 Examples of the cation ion include an ion represented by the following formula (5b), hydroxide ion, fluoride ion, chloride ion, bromide ion, iodide ion, cyanide ion, nitrate ion, nitrite ion, sulfate ion, sulfite ion, perchlorate ion, perbromate ion, periodate ion, chlorate ion, chlorite ion, hypochlorite ion, phosphate ion, phosphite ion, hypophosphite ion, borate ion, isocyanate ion, hydrosulfide ion, tetrafluoroborate ion, hexafluorophosphate ion, and hexachloroantimonate ion; carboxylate ions such as acetate ion, trifluoroacetate ion, and benzoate ion; sulfonate ions such as methanesulfonate and trifluoromethanesulfonate ion; and alkoxy ions such as methoxy ion and t-butoxy ion. [ka] (In the formula, E 2 represents an element belonging to Group 15 of the long-form periodic table, and X represents a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom.

[0259] In formula (5b), E2 is preferably a phosphorus atom, an arsenic atom, or an antimony atom, and is preferably a phosphorus atom in terms of the stability of the compound, ease of synthesis and purification, and toxicity. From the viewpoint of the stability of the compound and ease of synthesis and purification, X is preferably a fluorine atom or a chlorine atom, and most preferably a fluorine atom.

[0260] Among the above, the following formulas (10), (11), (12), and (13): [ka] An ionic compound having a combination of an anion and a cation represented by the following formula (see Japanese Patent No. 5381931 (Patent Document 5)) can be suitably used.

[0261] Heteropolyacid compounds are also particularly preferred as dopants. Heteropolyacid compounds have a structure in which a heteroatom is located at the center of the molecule, typically represented by a Keggin-type chemical structure shown in formula (A) or a Dawson-type chemical structure shown in formula (B), and are polyacids formed by condensing an isopolyacid, which is an oxyacid of vanadium (V), molybdenum (Mo), tungsten (W), or the like, with an oxyacid of a different element. Examples of such oxyacids of different elements include oxyacids of silicon (Si), phosphorus (P), and arsenic (As). [ka]

[0262] Specific examples of heteropolyacid compounds include phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, phosphotungstomolybdic acid, and silicotungstic acid. In consideration of the properties of an organic EL device having the resulting thin film, phosphomolybdic acid, phosphotungstic acid, and silicotungstic acid are preferred, with phosphotungstic acid being more preferred. These heteropolyacid compounds may be synthesized by known synthesis methods, but are also commercially available. For example, phosphotungstic acid hydrate (or 12-tungstophosphoric acid n-hydrate, chemical formula: H3(PW 12 O 40 )·nH2O) and phosphomolybdic acid hydrate (also known as 12-Molybdo(VI)phosphoric acid n-hydrate, chemical formula: H3(PMo 12 O 40 )·nH2O (n≒30)) is available from manufacturers such as Kanto Chemical Co., Ltd., Wako Pure Chemical Industries, Ltd., Sigma-Aldrich Japan, Ltd., Nippon Inorganic Chemical Industry Co., Ltd., and Nippon New Metals Co., Ltd.

[0263] In one embodiment, a sulfonate ester compound represented by the following formula (1), which is a precursor of the dopant, can also be used as the dopant. [ka]

[0264] In formula (1), R 1 ~R 4 each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms; R 5 represents an optionally substituted monovalent hydrocarbon group having 2 to 20 carbon atoms.

[0265] The linear or branched alkyl group is not particularly limited, but examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, etc. Among these, an alkyl group having 1 to 3 carbon atoms is preferred.

[0266] Examples of the monovalent hydrocarbon group having 2 to 20 carbon atoms include alkyl groups such as ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl groups, and aryl groups such as phenyl, naphthyl, and phenanthryl groups.

[0267] R 1 ~R 4 Among them, R 1 or R 3 is preferably a linear alkyl group having 1 to 3 carbon atoms, and the remainder is preferably a hydrogen atom. 1 is a linear alkyl group having 1 to 3 carbon atoms, and R 2 ~R 4 is preferably a hydrogen atom. The linear alkyl group having 1 to 3 carbon atoms is preferably a methyl group. 5と As the alkyl group, a linear alkyl group having 2 to 4 carbon atoms or a phenyl group is preferred.

[0268] In formula (1), A 1 represents -O- or -S-, with -O- being preferred. 2 represents an (n+1)-valent group derived from naphthalene or anthracene, with a group derived from naphthalene being preferred.3 represents an m-valent group derived from perfluorobiphenyl.

[0269] In formula (1), m represents an integer satisfying 2≦m≦4, preferably 2. n represents an integer satisfying 1≦n≦4, preferably 2.

[0270] In some embodiments, reaction by-products from the doping process may be removed, for example, metals such as silver may be removed by filtration.

[0271] For example, materials can be purified to remove halogens and metals. Halogens include, for example, chlorides, bromides, and iodides. Metals include, for example, dopant cations (including reduced forms of dopant cations) or metals left over from catalyst or initiator residues. Metals include, for example, silver, nickel, and magnesium. The amount can be, for example, less than 100 ppm, or less than 10 ppm, or less than 1 ppm.

[0272] Metal content, including silver content, can be measured by ICP-MS, especially at concentrations above 50 ppm.

[0273] In some embodiments, when the polythiophene is doped with a dopant, the polythiophene and the dopant are mixed to form a doped polymer composition. Mixing can be accomplished using any method known to those skilled in the art. For example, a solution containing the polythiophene can be mixed with another solution containing the dopant. The solvent used to dissolve the polythiophene and the dopant can be one or more of the solvents described herein. The reaction can occur by mixing the polythiophene and the dopant, as known in the art. The resulting doped polythiophene composition comprises, based on the composition, about 40% to 75% by weight of the polymer and about 25% to 55% by weight of the dopant. In another embodiment, the doped polythiophene composition comprises, based on the composition, about 50% to 65% by weight of the polythiophene and about 35% to 50% by weight of the dopant. Typically, the weight of the polythiophene is greater than the weight of the dopant. Typically, the dopant may be a silver salt such as silver tetrakis(pentafluorophenyl)borate in an amount of about 0.25 to 0.5 m / ru (where m is the molar amount of silver salt and ru is the molar amount of polymer repeat units).

[0274] The total solids content (% TS) in the ink composition of the present invention is about 0.1 wt % to about 50 wt %, typically about 0.3 wt % to about 40 wt %, more typically about 0.5 wt % to about 15 wt %, and even more typically about 1 wt % to about 5 wt %, based on the total amount of the ink composition.

[0275] The ink compositions described herein can be prepared by any suitable method known to those skilled in the art. For example, in one method, an initial aqueous mixture is prepared by mixing an aqueous dispersion of a polythiophene described herein with an optional aqueous dispersion of a polymeric acid, an optional additional matrix compound, and an optional additional solvent. The solvent, including water, in the mixture is then removed, typically by evaporation. The resulting dried product is dissolved or dispersed in one or more organic solvents, such as dimethyl sulfoxide, and filtered under pressure to produce a mixture. An amine compound may optionally be added to such a mixture. This mixture is then mixed with a dispersion of metal oxide nanoparticles to produce the final ink composition.

[0276] Alternatively, the ink compositions described herein can be prepared from stock solutions. For example, a stock solution of the polythiophene described herein can be prepared by isolating the polythiophene from an aqueous dispersion in a dry state, typically by evaporation. The dried polythiophene is then combined with one or more organic solvents and, optionally, an amine compound. Optionally, a stock solution of the polymeric acid described herein can be prepared by isolating the polymeric acid from an aqueous dispersion in a dry state, typically by evaporation. The dried polymeric acid is then combined with one or more organic solvents. Stock solutions of other optional matrix materials can be prepared similarly. A stock solution of metal oxide nanoparticles can be prepared, for example, by diluting a commercially available dispersion with one or more organic solvents, which may be the same or different from the solvent(s) contained in the commercially available dispersion. The desired amounts of each stock solution are then combined to form the ink composition of the present invention.

[0277] In yet another alternative, the ink compositions described herein can be prepared by isolating the individual components in a dry state as described herein, but instead of preparing a stock solution, combining the components in a dry state and then dissolving them in one or more organic solvents to provide the ink composition.

[0278] The ink compositions of the present invention can be cast and annealed as thin films on a substrate.

[0279] Thus, the present invention also provides a method for forming a hole-transporting thin film, comprising the steps of: 1) coating a substrate with the ink composition disclosed herein; and 2) Annealing the coating on the substrate to form a hole-transporting thin film. The present invention relates to a method comprising:

[0280] Coating the ink composition on the substrate can be carried out by methods known in the art, including, for example, spin casting, spin coating, dip casting, dip coating, slot die coating, inkjet printing, gravure coating, doctor blading, and any other method known in the art for, for example, fabrication of organic electronic devices. Preferably, the substrate is coated with the ink composition by inkjet printing.

[0281] The substrate may be flexible or rigid, organic or inorganic. Suitable substrate compounds include, for example, glass (including, for example, display glass), ceramic, metal, and plastic thin films.

[0282] As used herein, the term "annealing" refers to any general process for forming a cured layer, typically a thin film, on a substrate coated with the ink composition of the present invention. General annealing processes are known to those skilled in the art. Typically, the solvent is removed from the substrate coated with the ink composition. Solvent removal can be achieved, for example, by subjecting the coated substrate to a pressure less than atmospheric pressure and / or by heating the coating deposited on the substrate to a certain temperature (annealing temperature), maintaining this temperature for a certain period of time (annealing time), and then allowing the resulting layer, typically a thin film, to slowly cool to room temperature.

[0283] The annealing step can be carried out by heating the substrate coated with the ink composition using any method known to those skilled in the art, for example, by heating in an oven or on a hot plate. Annealing can be carried out in an inert environment, for example, in a nitrogen atmosphere or a noble gas atmosphere (e.g., argon gas). Annealing can also be carried out in an air atmosphere.

[0284] In certain embodiments, the annealing temperature is from about 25°C to about 350°C, typically from 150°C to about 325°C, more typically from about 200°C to about 300°C, and even more typically from about 230°C to about 300°C.

[0285] The annealing time is the time during which the annealing temperature is maintained, and is about 3 to about 40 minutes, typically about 15 to about 30 minutes.

[0286] In one embodiment, the annealing temperature is about 25°C to about 350°C, typically 150°C to about 325°C, more typically about 200°C to about 300°C, and even more typically about 250°C to about 300°C, and the annealing time is about 3 to about 40 minutes, typically about 15 to about 30 minutes.

[0287] The present invention relates to hole transporting thin films formed by the methods described herein.

[0288] Visible light transmission is important, and good transmission (low absorption) is especially important at thicker films. For example, films produced by the methods of the present invention can exhibit a transmittance (typically with the substrate) of at least about 85%, typically at least 90%, of light having a wavelength of about 380-800 nm. In some embodiments, the transmittance is at least about 90%.

[0289] In one embodiment, the thin film produced by the method of the present invention has a thickness of about 5 nm to about 500 nm, typically about 5 nm to about 150 nm, and more typically about 50 nm to 120 nm.

[0290] In some embodiments, thin films produced by the methods of the present invention exhibit a transmittance of at least about 90% and have a thickness of about 5 nm to about 500 nm, typically about 5 nm to about 150 nm, and more typically about 50 nm to 120 nm. In some embodiments, thin films produced by the methods of the present invention exhibit a transmittance (%T) of at least about 90% and have a thickness of about 50 nm to 120 nm.

[0291] Thin films produced by the methods of the present invention can be fabricated on substrates that optionally contain electrodes or additional layers used to enhance the electronic properties of the final device. The resulting thin films can be resistant to one or more organic solvents, which can be solvents used as liquid carriers in inks for subsequent layers coated or deposited during device fabrication. For example, thin films can be resistant to toluene, which can be a solvent in inks for subsequent layers coated or deposited during device fabrication.

[0292] The present invention also relates to devices comprising thin films prepared by the methods described herein. The devices described herein can be fabricated by methods known in the art, including, for example, solution methods. The ink can be applied and the solvent removed by standard methods. The thin films prepared by the methods described herein can be HIL and / or HTL layers in the device.

[0293] Methods are known in the art and can be used to fabricate organic electronic devices, including, for example, OLED and OPV devices. Methods known in the art can be used to measure luminance, efficiency, and lifetime. Organic light-emitting diodes (OLEDs) are described, for example, in U.S. Pat. Nos. 4,356,429 and 4,539,507 (Kodak). Light-emitting conductive polymers are described, for example, in U.S. Pat. Nos. 5,247,190 and 5,401,827 (Cambridge Display Technologies). Device architectures, physical principles, solution methods, layering, blending, and compound synthesis and formulation are described in Kraft et al., "Electroluminescent Conjugated Polymers—Seeing Polymers in a New Light," Angew. Chem. Int. Ed., 1998, 37, 402-428, which is incorporated herein by reference in its entirety.

[0294] Known in the art and commercially available light emitters can be used, including various conductive polymers and organic molecules, such as compounds available from Sumation, Merck Yellow, Merck Blue, American Dye Sources (ADS), Kodak (e.g., A1Q3), and even Aldrich (e.g., BEHP-PPV). Examples of such organic electroluminescent compounds include: (i) poly(p-phenylene vinylene) and its derivatives substituted at various positions on the phenylene residue; (ii) poly(p-phenylene vinylene) and its derivatives substituted at various positions on the vinylene residue; (iii) poly(p-phenylene vinylene) and its derivatives substituted at various positions on the phenylene residue and also substituted at various positions on the vinylene residue; (iv) poly(arylenevinylenes), where the arylene can be a residue such as naphthalene, anthracene, furylene, thienylene, oxadiazole, and the like; (v) Derivatives of poly(arylene vinylene), in which the arylene may be as in (iv) above and further has substituents at various positions on the arylene; (vi) Derivatives of poly(arylene vinylene), in which the arylene may be as in (iv) above and further has substituents at various positions on the vinylene; (vii) Derivatives of poly(arylene vinylene), in which the arylene may be as in (iv) above, and further having substituents at various positions on the arylene and substituents at various positions on the vinylene; (viii) copolymers of arylene vinylene oligomers and non-conjugated oligomers, such as the compounds in (iv), (v), (vi), and (vii); and (ix) poly(p-phenylene) and its derivatives substituted at various positions on the phenylene residue (including ladder polymer derivatives such as poly(9,9-dialkylfluorene)); (x) Poly(arylenes), where the arylene may be a residue such as naphthalene, anthracene, furylene, thienylene, oxadiazole, etc.; and derivatives thereof substituted at various positions on the arylene residue; (xi) Copolymers of oligoarylenes such as the compounds in (x) with non-conjugated oligomers; (xii) Polyquinoline and its derivatives; (xiii) copolymers of polyquinoline and p-phenylene substituted on the phenylene by, for example, alkyl or alkoxy groups to provide solubility; (xiv) Rigid rod polymers and derivatives thereof, such as poly(p-phenylene-2,6-benzobisthiazole), poly(p-phenylene-2,6-benzobisoxazole), poly(p-phenylene-2,6-benzimidazole), and derivatives thereof; (xv) Polyfluorene polymers and copolymers having polyfluorene units.

[0295] Preferred organic light-emitting polymers include SUMATION's Light Emitting Polymers ("LEPs") or families, copolymers, derivatives, or mixtures thereof that emit green, red, blue, or white light; SUMATION's LEPs are available from Sumation KK. Other polymers include polyspirofluorene-like polymers available from Covion Organic Semiconductors GmbH, Frankfurt, Germany (now owned by Merck®).

[0296] Alternatively, instead of polymers, fluorescent or phosphorescent organic small molecules can be used as the organic electroluminescent layer. Examples of small molecule organic electroluminescent compounds include (i) tris(8-hydroxyquinolinato)aluminum (Alq); (ii) 1,3-bis(N,N-dimethylaminophenyl)-1,3,4-oxadiazole (OXD-8); (iii) oxo-bis(2-methyl-8-quinolinato)aluminum; (iv) bis(2-methyl-8-hydroxyquinolinato)aluminum; (v) bis(hydroxybenzoquinolinato)beryllium (BeQ2); (vi) bis(diphenylvinyl)biphenylene (DPVBI); and arylamine-substituted distyrylarylene (DSA amine).

[0297] Such polymers and small molecule compounds are well known in the art and are described, for example, in US Pat. No. 5,047,687.

[0298] Devices can often be fabricated using multilayer structures that can be prepared, for example, by solution or vacuum processes, as well as by printing and patterning techniques. In particular, the use of the embodiments described herein for hole injection layers (HILs), in which the compositions are formulated for use as hole injection layers, can be effectively implemented.

[0299] Examples of HIL in devices include: 1) Hole injection in OLEDs, including PLEDs and SMOLEDs; for example, the HIL in a PLED can be any class of conjugated polymer emitter, where the conjugation involves carbon or silicon atoms. Examples of HILs in SMOLEDs include: SMOLEDs containing fluorescent emitters; SMOLEDs containing phosphorescent emitters; SMOLEDs containing one or more organic layers in addition to the HIL layer; and SMOLEDs in which small molecule layers are processed from solutions or aerosol sprays, or by any other processing method. Further examples include: HILs in OLEDs based on dendrimer or oligomer organic semiconductors; HILs in ambipolar light-emitting FETs, where the HIL is used to regulate charge injection or as an electrode; 2) hole extraction layer in OPV; 3) channel material in transistors; 4) Channel materials in circuits containing combinations of transistors, such as logic gates; 5) electrode materials in transistors; 6) Gate layer in the capacitor; 7) Chemical sensors in which the adjustment of the doping level is achieved by the relationship between the species to be sensed and the conducting polymer; 8) Electrode or electrolyte materials in batteries.

[0300] A variety of photoactive layers can be used in OPV devices. Photovoltaic devices can be prepared with a photoactive layer comprising, for example, a fullerene derivative mixed with a conductive polymer, as described, for example, in U.S. Patent Nos. 5,454,880; 6,812,399; and 6,933,436. Photoactive layers can include blends of conductive polymers, blends of conductive polymers and semiconductor nanoparticles, and bilayers of small molecules such as phthalocyanines, fullerenes, and porphyrins.

[0301] Common electrode compounds and substrates as well as encapsulation compounds can be used.

[0302] In one embodiment, the cathode comprises Au, Ca, Al, Ag, or a combination thereof. In one embodiment, the anode comprises indium tin oxide. In one embodiment, the light-emitting layer comprises at least one organic compound.

[0303] For example, interface modification layers such as interlayers and optical spacer layers can be used.

[0304] An electron transport layer may be used.

[0305] The present invention also relates to methods of manufacturing the devices described herein.

[0306] In one embodiment, a method for making a device includes: providing a substrate; depositing a transparent conductor, such as indium tin oxide, on the substrate; providing an ink composition described herein; depositing the ink composition on the transparent conductor to form a hole injection layer or hole transport layer; depositing an active layer on the hole injection layer or hole transport layer (HTL); and depositing a cathode on the active layer.

[0307] As described herein, the substrate may be flexible or rigid, organic or inorganic. Suitable substrate compounds include, for example, glass, ceramic, metal, and plastic thin films.

[0308] In another embodiment, a method of manufacturing a device comprises applying an ink composition described herein as part of a HIL or HTL layer in an OLED, a photovoltaic device, an ESD, a SMOLED, a PLED, a sensor, a supercapacitor, a cation converter, a drug release device, an electrochromic device, a transistor, a field effect transistor, an electrode modifier, an electrode modifier for an organic field effect transistor, an actuator, or a transparent electrode.

[0309] Deposition of the ink composition to form the HIL or HTL layer can be carried out by methods known in the art, including, for example, spin casting, spin coating, dip casting, dip coating, slot die coating, inkjet printing, gravure coating, doctor blading, and any other method known in the art, for example, for fabricating organic electronic devices. Deposition of the ink composition by inkjet printing is preferred.

[0310] In one embodiment, the HIL layer is thermally annealed. In one embodiment, the HIL layer is thermally annealed at a temperature of about 25° C. to about 350° C., typically 150° C. to about 325° C. In one embodiment, the HIL layer is thermally annealed at a temperature of about 25° C. to about 350° C., typically 150° C. to about 325° C., for about 3 to about 40 minutes, typically about 15 to about 30 minutes.

[0311] In one embodiment, the HIL layer has a thickness of about 5 nm to about 500 nm, typically about 5 nm to about 150 nm, and more typically about 50 nm to 120 nm.

[0312] In some embodiments, the HIL layer exhibits a transmittance of at least about 90% and has a thickness of about 5 nm to about 500 nm, typically about 5 nm to about 150 nm, and more typically about 50 nm to 120 nm. In some embodiments, the HIL layer exhibits a transmittance (%T) of at least about 90% and has a thickness of about 50 nm to 120 nm.

[0313] The ink composition and organic EL device of the present invention are further illustrated by the following non-limiting examples. [Example]

[0314] The abbreviations used in the following examples have the following meanings. MMA: Methyl methacrylate HEMA: 2-hydroxyethyl methacrylate HPMA: 4-hydroxyphenyl methacrylate HPMA-QD: A compound synthesized by the condensation reaction of 1 mol of 4-hydroxyphenyl methacrylate and 1.1 mol of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride. CHMI: N-cyclohexylmaleimide PFHMA: 2-(perfluorohexyl)ethyl methacrylate MAA: methacrylic acid AIBN: α,α'-azobisisobutyronitrile QD1: A compound synthesized by the condensation reaction of 1 mol of α,α,α'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene with 1.5 mol of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride. GT-401: butanetetracarboxylic acid tetra(3,4-epoxycyclohexylmethyl) modified ε-caprolactone (product name: Epolead GT-401 (manufactured by Daicel Corporation)) PGME: Propylene glycol monomethyl ether PGMEA: Propylene glycol monomethyl ether acetate CHN: Cyclohexanone

[0315] The ingredients used in the following examples are summarized in Tables 1 and 2 below. [Table 1] [Table 2]

[0316] In the following examples, arylsulfonic acids represented by the following formula may be used. [ka]

[0317] [1] Preparation of charge-transporting materials [Manufacturing Example 1] Preparation of S-poly(3-MEET) amine adducts 500 g of an aqueous dispersion of S-poly(3-MEET) (0.598% solids in water) was mixed with 0.858 g of triethylamine, and the resulting mixture was evaporated to dryness by rotary evaporation. The resulting residue was then further dried overnight at 50 °C in a vacuum oven to yield 3.8 g of S-poly(3-MEET) amine adduct as a black powder.

[0318] [Manufacturing Example 2] 2.00 g of the S-poly(3-MEET) amine adduct obtained in Production Example 1 was dissolved in 100 mL of 28% aqueous ammonia (Junsei Chemical Co., Ltd.), and the resulting solution was stirred overnight at room temperature. The resulting reaction mixture was subjected to reprecipitation with 1500 mL of acetone, and the precipitate was collected by filtration. The resulting precipitate was redissolved in 20 mL of water and 7.59 g of triethylamine (Tokyo Chemical Industry Co., Ltd.) and stirred at 60°C for 1 hour. The resulting reaction mixture was cooled and then subjected to reprecipitation with a mixed solvent of 1000 mL of isopropyl alcohol and 500 mL of acetone, and the precipitate was collected by filtration. The resulting precipitate was vacuum-dried at 0 mmHg and 50°C for 1 hour to obtain 1.30 g of S-poly(3-MEET)-A, a charge-transporting material treated with aqueous ammonia.

[0319] [2] Preparation of charge-transporting varnish [Example 1] First, the solvent in the D66-20BS aqueous solution was removed using an evaporator, and the resulting residue was dried under reduced pressure at 80°C for 1 hour in a vacuum dryer to obtain D66-20BS powder. A 5 wt% ethylene glycol solution of D66-20BS was prepared using the resulting powder. The solution was prepared by stirring at 400 rpm and 80°C for 1 hour using a hot stirrer. Next, in a separate container, 0.020 g of S-poly(3-MEET)-A obtained in Production Example 2 was dissolved in 1.59 g of ethylene glycol (Kanto Chemical Co., Ltd.), 0.49 g of triethylene glycol (Kanto Chemical Co., Ltd.), 1.95 g of triethylene glycol butyl methyl ether (Tokyo Chemical Industry Co., Ltd.), 4.88 g of diethylene glycol monobutyl ether (Kanto Chemical Co., Ltd.), and 0.032 g of 2-ethylhexylamine (Tokyo Chemical Industry Co., Ltd.). The solution was prepared by stirring at 80°C for 1 hour using a hot stirrer. Next, 0.20 g of a 5 wt% ethylene glycol solution of D66-20BS was added to the resulting solution, and the resulting mixture was stirred at 400 rpm at room temperature for 10 minutes. Finally, 0.83 g of EG-ST was added, and the resulting mixture was stirred using a stirrer at 400 rpm at room temperature for 10 minutes. The resulting dispersion was filtered through a PP syringe filter with a pore size of 0.2 μm to obtain a 2 wt % charge-transporting varnish.

[0320] [Example 2] Charge-transporting varnish B was obtained in the same manner as in Example 1, except that the solvent was changed to 1.59 g of ethylene glycol (manufactured by Kanto Chemical Co., Ltd.), 0.49 g of triethylene glycol (manufactured by Kanto Chemical Co., Ltd.), 2.93 g of triethylene glycol butyl methyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.), and 3.91 g of diethylene glycol monoisobutyl ether (manufactured by Kanto Chemical Co., Ltd.).

[0321] [Example 3] Charge-transporting varnish C was obtained in the same manner as in Example 1, except that the solvent was changed to 1.33 g of ethylene glycol (manufactured by Kanto Chemical Co., Ltd.), 0.68 g of triethylene glycol (manufactured by Kanto Chemical Co., Ltd.), 2.93 g of triethylene glycol butyl methyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.), and 3.91 g of diethylene glycol monobutyl ether (manufactured by Kanto Chemical Co., Ltd.), and that 0.83 g of EG-ST was changed to 0.75 g of EG-ST and 0.15 g of EG silica sol (2).

[0322] [Example 4] Charge-transporting varnish D was obtained in the same manner as in Example 1, except that the solvent was changed to 1.52 g of ethylene glycol (manufactured by Kanto Chemical Co., Ltd.), 0.49 g of triethylene glycol (manufactured by Kanto Chemical Co., Ltd.), 2.93 g of triethylene glycol butyl methyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.), and 3.91 g of diethylene glycol monobutyl ether (manufactured by Kanto Chemical Co., Ltd.), and that 0.83 g of EG-ST was changed to 0.75 g of EG-ST and 0.15 g of EG silica sol (2).

[0323] [Example 5] Charge-transporting varnish G was obtained in the same manner as in Example 1, except that the solvent was changed to 1.03 g of ethylene glycol (manufactured by Kanto Chemical Co., Ltd.), 0.98 g of triethylene glycol (manufactured by Kanto Chemical Co., Ltd.), 2.93 g of triethylene glycol butyl methyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.), and 3.91 g of diethylene glycol monobutyl ether (manufactured by Kanto Chemical Co., Ltd.), and that 0.83 g of EG-ST was changed to 0.75 g of EG-ST and 0.15 g of EG silica sol (2).

[0324] [Comparative Example 1] Charge-transporting varnish F was obtained in the same manner as in Example 1, except that the solvent was changed to 0.62 g of ethylene glycol (manufactured by Kanto Chemical Co., Ltd.), 1.47 g of diethylene glycol (manufactured by Kanto Chemical Co., Ltd.), 1.95 g of diethylene glycol dibutyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.), and 4.88 g of diethylene glycol monobutyl ether (manufactured by Kanto Chemical Co., Ltd.).

[0325] The solvent compositions used in Examples 1 to 5 and Comparative Example 1 are shown in Table 3 below. [Table 3]

[0326] [Example 6] First, the methanol contained in MT-ST was replaced with TPG using an evaporator to obtain a 20.6 wt% silica dispersion, TPG-ST. A propylene glycol solution containing 10% by mass of arylsulfonic acid (arylsulfonic acid B) represented by the above formula (b-1) was prepared. The solution was prepared by stirring at 400 rpm and 50°C for 1 hour using a hot stirrer. Next, in a separate container, 0.020 g of S-poly(3-MEET)-A obtained in Production Example 2 was dissolved in 0.71 g of propylene glycol (Junsei Chemical Co., Ltd.), 2.391 g of tripropylene glycol (Kanto Chemical Co., Ltd.), 2.930 g of propylene carbonate (Tokyo Chemical Industry Co., Ltd.), 0.977 g of dipropylene glycol monobutyl ether (Fujifilm Wako Pure Chemical Industries Co., Ltd.), 1.954 g of diisopropyl malonate (Tokyo Chemical Industry Co., Ltd.), and 0.032 g of 2-ethylhexylamine (Tokyo Chemical Industry Co., Ltd.). The solution was prepared by stirring at 80°C for 1 hour using a hot stirrer. Next, 0.30 g of a 10 wt% propylene glycol solution of the above formula (b-1) was added to the resulting solution, and the resulting mixture was stirred at 400 rpm at room temperature for 10 minutes using a stirrer. Next, 0.68 g of TPG-ST was added, and the resulting mixture was stirred at 400 rpm at room temperature for 10 minutes using a stirrer. Finally, 0.01 g of KBM-7103 (manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and the resulting mixture was stirred at 400 rpm at room temperature for 10 minutes using a stirrer. The resulting dispersion was filtered through a PP syringe filter with a pore size of 0.2 μm to obtain 2 wt % of charge-transporting varnish H.

[0327] [Example 7] A dipropylene glycol solution containing 10% by mass of arylsulfonic acid (arylsulfonic acid B) represented by the above formula (b-1) was prepared. The solution was prepared by stirring at 400 rpm and 50°C for 1 hour using a hot stirrer. Next, in a separate container, 0.020 g of S-poly(3-MEET)-A obtained in Production Example 2 was dissolved in 0.71 g of dipropylene glycol (Junsei Chemical Co., Ltd.), 1.414 g of tripropylene glycol (Kanto Chemical Co., Ltd.), 1.954 g of propylene carbonate (Tokyo Chemical Industry Co., Ltd.), 1.954 g of triethylene glycol monobutyl ether (Tokyo Chemical Industry Co., Ltd.), 2.930 g of diisopropyl malonate (Tokyo Chemical Industry Co., Ltd.), and 0.032 g of 2-ethylhexylamine (Tokyo Chemical Industry Co., Ltd.). The solution was prepared by stirring at 80°C for 1 hour using a hot stirrer. Next, 0.30 g of a 10 wt% propylene glycol solution of the above formula (b-1) was added to the resulting solution, and the resulting mixture was stirred at 400 rpm at room temperature for 10 minutes using a stirrer. Next, 0.68 g of TPG-ST prepared in Example 6 was added, and the resulting mixture was stirred at 400 rpm at room temperature for 10 minutes using a stirrer. Finally, 0.01 g of KBM-7103 (manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and the resulting mixture was stirred at 400 rpm at room temperature for 10 minutes using a stirrer. The resulting dispersion was filtered through a PP syringe filter with a pore size of 0.2 μm to obtain 2 wt % charge-transporting varnish I.

[0328] The compositions (wt%) of the solvents used in Examples 6 and 7 are shown in Table 4 below. [Table 4]

[0329] [3] Preparation of positive photosensitive resin composition [Measurement of number average molecular weight and weight average molecular weight] The number average molecular weight and weight average molecular weight of the copolymers obtained according to the following synthesis examples were measured by gel permeation chromatography under the following conditions. Chromatograph: Shimadzu GPC equipment Detector (RID10A) Liquid delivery unit (LC-20AD) Column oven (CTO20A) Column: Shodex KF-804L and 803L (Showa Denko) connected in series Eluent: tetrahydrofuran ·Flow rate: 1ml / min Column temperature: 40℃ The number average molecular weight (hereinafter referred to as Mn) and weight average molecular weight (hereinafter referred to as Mw) below are expressed in polystyrene equivalent values.

[0330] <Synthesis Example 1> 10.0 g of MMA, 12.5 g of HEMA, 20.0 g of CHMI, 2.50 g of HPMA, 5.00 g of MAA, and 3.20 g of AIBN were dissolved in 79.8 g of PGME and reacted at 60 to 100° C. for 20 hours to obtain an acrylic polymer solution (solid concentration 40% by mass) (P1). The resulting acrylic polymer P1 had an Mn of 3,700 and an Mw of 6,100. <Synthesis Example 2> 2.50 g of HPMA-QD, 7.84 g of PFHMA, 0.70 g of MAA, 1.46 g of CHMI, and 0.33 g of AIBN were dissolved in 51.3 g of CHN and reacted with stirring at 110°C for 20 hours to obtain an acrylic polymer solution (solids concentration: 20% by mass) (P2). The resulting acrylic polymer P2 had an Mn of 4,300 and an Mw of 6,300.

[0331] A positive photosensitive resin composition was prepared by mixing 5.04 g of P1 obtained in Synthesis Example 1, 0.05 g of P2 obtained in Synthesis Example 2, 0.40 g of QD1, 0.09 g of GT-401, and 6.42 g of PGMEA and stirring at room temperature for 3 hours to obtain a homogeneous solution.

[0332] [4] Preparation of substrate with bank The positive photosensitive resin composition obtained in the above step [3] was applied using a spin coater onto an ITO-glass substrate that had been ozone-cleaned for 10 minutes using UV-312 manufactured by Technovision Co., Ltd., and the substrate was then pre-baked on a hot plate (heated at a temperature of 100°C for 120 seconds) to form a thin film with a thickness of 1.2 μm. This thin film was then irradiated with ultraviolet light (light intensity at 365 nm: 5.5 mW / cm ) using an ultraviolet irradiation device PLA-600FA manufactured by Canon Inc., through a mask with a pattern of many rectangles with long sides of 200 μm and short sides of 100 μm. 2 ) for a certain period of time. The thin film was then immersed in a 1.0% TMAH aqueous solution for 120 seconds for development, and then washed with running ultrapure water for 20 seconds. The thin film with the rectangular pattern formed was then post-baked (heated at 230°C for 30 minutes) to harden it, producing a substrate with banks.

[0333] [5] Film formation evaluation The charge-transporting varnishes obtained in Examples 1 to 7 and Comparative Example 1 were ejected into the rectangular openings (film formation areas) on the substrate with banks obtained in step [4] using an Inkjet Designer manufactured by Cluster Technology Co., Ltd. The resulting coating films were dried under reduced pressure (vacuum) of 10 Pa or less for 15 minutes, and then dried on a hot plate at 230°C for 30 minutes to form charge-transporting thin films. The cross-sectional shapes of the charge transporting thin films obtained in Examples 1 to 7 and Comparative Example 1 were measured using a micro-profile measuring instrument ET4000A (manufactured by Kosaka Laboratory Co., Ltd.) The results are shown in Fig. 1 (Examples 1 to 5 and Comparative Example 1) and Fig. 2 (Examples 6 to 7 and Comparative Example 1) for the openings, respectively.

[0334] Comparing Examples 1 to 5 with Comparative Example 1 (FIG. 1), the cross-sectional shapes of the charge-transporting thin films obtained in the Examples clearly show less film creeping (increase in film thickness) near the bank compared to the cross-sectional shapes of the thin films obtained in the Comparative Example. That is, pile-up is suppressed in the Examples compared to the Comparative Example. From the above results, it was confirmed that use of the non-aqueous ink composition of the present invention makes it possible to suppress pile-up during the formation of a charge-transporting thin film. As a result, it is expected that in organic EL devices obtained using the non-aqueous ink composition of the present invention, shortened lifespan due to electrical defects and uneven emission due to non-uniform thickness of the light-emitting layer will be significantly improved without excessively degrading other properties.

[0335] Comparing Examples 6 and 7 with Comparative Example 1 (FIG. 2), the cross-sectional shape of the charge-transporting thin film obtained in the Examples clearly shows less film creeping up (increase in film thickness) near the bank compared to the cross-sectional shape of the thin film obtained in the Comparative Example. In other words, pile-up is suppressed in the Examples compared to the Comparative Example.

[0336] [6] Fabrication and characterization of organic EL devices The varnishes obtained in Examples 1, 6, and 7 and Comparative Example 1 were each applied to a banked ITO substrate using a spin coater and then dried under reduced pressure (vacuum) of 10 Pa or less in air for 15 minutes. The dried substrate was then placed in a glove box and baked at 230°C for 30 minutes to form a 50 nm thin film on the substrate. The banked ITO substrate was prepared by forming a 1.1 μm thick polyimide resin film on the electrode surface of a 25 mm × 25 mm × 0.7 mm glass substrate with a patterned indium tin oxide (ITO) thin film electrode with a thickness of 150 nm. This film was then patterned (with numerous 2 × 2 mm squares) to form banks. Prior to use, surface impurities were removed using an O2 plasma cleaning device (150 W, 30 seconds). Next, the ITO substrate on which the thin film was formed was subjected to a deposition apparatus (vacuum degree 1.0 × 10 -5A 30-nm film of α-NPD (N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine) was deposited at 0.2 nm / sec using a fluorine-containing fluoride (PA). Next, a 10-nm film of the electron blocking material HTEB-01 (Kanto Chemical Co., Ltd.) was deposited. Next, the emitting layer host material NS60 (Nippon Steel & Sumikin Chemical Co., Ltd.) and the emitting layer dopant material Ir(PPy)3 were co-deposited. The deposition rate was controlled so that the Ir(PPy)3 concentration was 6%, resulting in a 40-nm layer. Next, thin films of Alq3, lithium fluoride, and aluminum were sequentially deposited to obtain an organic EL device. The deposition rates were 0.2 nm / sec for Alq3 and aluminum, and 0.02 nm / sec for lithium fluoride, resulting in film thicknesses of 20 nm, 0.5 nm, and 80 nm, respectively. To prevent deterioration of characteristics due to the influence of oxygen, water, etc. in the air, the organic EL elements were sealed with sealing substrates before their characteristics were evaluated. Sealing was performed as follows: In a nitrogen atmosphere with an oxygen concentration of 2 ppm or less and a dew point of -76°C or less, the organic EL elements were placed between sealing substrates, and the sealing substrates were bonded together with an adhesive (MORESCO Moisture Cut WB90US(P), manufactured by MORESCO Corporation). At this time, a moisture scavenger (HD-071010W-40, manufactured by DYNIC Corporation) was placed inside the sealing substrates together with the organic EL elements. The bonded sealing substrates were irradiated with UV light (wavelength: 365 nm, irradiation dose: 6,000 mJ / cm). 2 ), and then annealed at 80°C for 1 hour to cure the adhesive.

[0337] [ka]

[0338] Of the organic EL devices obtained above, those produced using the varnishes obtained in Example 1 and Comparative Example 1 had a luminance of 10,000 cd / m 2 The driving voltage, current density, luminous efficiency, and luminance life LT70 (initial luminance 10000 cd / m 2 The time it took for the electrical conductivity to decrease by 30% was measured. The results are shown in Table 5.

[0339] [Table 5]

[0340] In addition, among the organic EL devices obtained above, those produced using the varnishes obtained in Examples 6 to 7 and Comparative Example 1 had a luminance of 10,000 cd / m 2 The driving voltage, current density, luminous efficiency, and luminance life LT70 (initial luminance 10000 cd / m 2 The time it took for the electrical conductivity to decrease by 30% was measured. The results are shown in Table 6.

[0341] [Table 6]

[0342] As shown in Tables 5 and 6, the organic EL device prepared using the non-aqueous ink composition of the present invention had improved current efficiency and extended luminance life, reflecting the suppression of pile-up.

Claims

1. A charge transport thin film, (a) Charge transporting substance; (b) one or more metal oxide nanoparticles; and (c) a liquid carrier, (c-1) Boiling point bp １ a first hydrophilic glycol-based solvent having a viscosity of (°C); (c-2) Boiling point bp ２ a second hydrophilic glycol-based solvent having a temperature (°C), and (c-3) Boiling point bp ３ (°C) Including, bp １ <bp ３ <bp ２ and bp １ is 180°C or more, and bp ２ is 270°C or higher, and bp ３ the liquid carrier is 200°C or higher and lower than 270°C A charge transporting thin film obtained from an ink composition comprising:

2. 2. The charge transporting thin film according to claim 1, wherein the solvent (c-3) is a hydrophobic glycol solvent, a nitrile, an alcohol, an aromatic ether, an aromatic ester, or an aromatic hydrocarbon.

3. 3. The charge transporting thin film according to claim 1, wherein the solvent (c-3) is a hydrophobic glycol solvent.

4. 4. The charge transporting thin film according to claim 1, wherein the solvents (c-1) and (c-2) are both glycol solvents, and the solvent (c-3) is a glycol diether solvent.

5. 2. The charge transporting thin film according to claim 1, wherein the solvent (c-3) is a mixture of two or more organic solvents containing one or more glycol diether solvents.

6. 6. The charge transporting thin film according to claim 1, wherein the solvent (c-1) is ethylene glycol.

7. 7. The charge transporting thin film according to claim 1, wherein the solvent (c-2) is triethylene glycol.

8. 8. The charge transporting thin film according to claim 1, wherein the weight ratio ((c-1):(c-2)) of the solvent (c-1) to the solvent (c-2) is 29:1 to 8:

7.

9. 9. The charge transporting thin film according to claim 1, wherein the weight of the solvent (c-1) is 16 to 29% of the total weight of the liquid carrier (c), and the weight of the solvent (c-2) is 14 to 1% of the total weight of the liquid carrier (c).

10. The metal oxide nanoparticles (b) are B ２ O ３ , B ２ O, SiO ２ , SiO, GeO ２ , GeO, As ２ O ４ , As ２ O ３ , As ２ O ５ , Sb ２ O ３ , TeO ２ , SnO ２ 10. The charge transporting thin film according to claim 1, comprising SnO, SnO or a mixture thereof.

11. The metal oxide nanoparticles (b) are SiO ２ The charge transporting thin film according to claim 10, comprising:

12. 12. The charge transporting thin film according to claim 1, wherein the charge transporting substance (a) is a polythiophene.

13. The polythiophene is represented by the following formula (I): 【Chemistry 45】 [In the formula, R １ and R ２ are each independently H, alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, aryloxy, —SO ３ M, or —O—[Z—O] ｐ -R ｅ or R １ and R ２ come together to form -O-Z-O- (In the formula, M is H, an alkali metal, ammonium, monoalkylammonium, dialkylammonium, or trialkylammonium; Z is a hydrocarbylene group optionally substituted with halogen or Y, wherein Y is a linear or branched alkyl or alkoxyalkyl group having 1 to 10 carbon atoms, and the alkyl or alkoxyalkyl group may be substituted with a sulfonic acid group at any position; p is an integer greater than or equal to 1, and R ｅ is H, alkyl, fluoroalkyl, or aryl).

13. The charge transporting thin film according to claim 12, which is a polythiophene containing a repeating unit represented by the following formula:

14. R １ and R ２ are each independently H, fluoroalkyl, or —SO ３ M, -O[C(R ａ R ｂ )-C(R ｃ R ｄ ) -O] ｐ -R ｅ , or -OR ｆ or R １ and R ２ are joined together to form -O-(CH ２ ) ｑ -O- (wherein, (CH ２ ) ｑ optionally substituted with Y; where M is H, alkali metal, ammonium, monoalkylammonium, dialkylammonium, or trialkylammonium, and each R ａ , R ｂ , R ｃ , and R ｄ are each independently H, halogen, alkyl, fluoroalkyl, or aryl; R ｅ is H, alkyl, fluoroalkyl, or aryl; p is 1, 2, or 3; R ｆ is alkyl, fluoroalkyl, or aryl; q is 1, 2, or 3; and Y is a linear or branched alkoxyalkyl group having 1 to 10 carbon atoms, which may be substituted with a sulfonic acid group at any position.

15. R １ is H and R ２ The charge transporting thin film according to claim 14, wherein is other than H.

16. R １ and R ２ and both are other than H.

17. R １ and R ２ are each independently —O[C(R ａ R ｂ )-C(R ｃ R ｄ ) -O] ｐ -R ｅ , or -OR ｆ or R １ and R ２ are joined together to form -O-(CH ２ ) ｑ The charge transporting thin film according to claim 16, which forms —O—.

18. R １ and R ２ However, both are -O[C(R ａ R ｂ )-C(R ｃ R ｄ ) -O] ｐ -R ｅ 18. The charge transporting thin film according to claim 17, wherein

19. Each R ａ , R ｂ , R ｃ and R ｄ are each independently H, (C １ -C ８ ) alkyl, (C １ -C ８ ) fluoroalkyl or phenyl; R ｅ However, (C １ -C ８ ) alkyl, (C １ -C ８ 15. The charge transporting thin film according to claim 14, wherein the aryl group is fluoroalkyl or phenyl.

20. The polythiophene has the following formula: 【Chemistry 46】 wherein M is H, an alkali metal, ammonium, monoalkylammonium, dialkylammonium, or trialkylammonium.

15. The charge transporting thin film according to claim 12, comprising a repeating unit selected from the group consisting of groups represented by the following formula: and combinations thereof.

21. The charge transporting thin film according to any one of claims 12 to 20, wherein the polythiophene is sulfonated.

22. 22. The charge transporting thin film according to claim 12, wherein the polythiophene is sulfonated poly(3-MET).

23. 23. The charge transporting thin film according to any one of claims 12 to 22, wherein the polythiophene comprises repeat units represented by formula (I) in an amount greater than 50 wt%, typically greater than 80 wt%, more typically greater than 90 wt%, and even more typically greater than 95 wt%, based on the total weight of the repeat units.

24. 24. The charge transporting thin film according to claim 1, further comprising a synthetic polymer containing one or more acidic groups.

25. The synthetic polymer contains at least one fluorine atom and at least one sulfonic acid (—SO ３ 25. The charge transporting thin film of claim 24, which is a polymeric acid comprising one or more repeating units containing at least one alkyl or alkoxy group substituted with a (H) residue, optionally interrupted by at least one ether bond (-O-).

26. The polymer acid comprises a repeating unit represented by the following formula (II) and a repeating unit represented by the following formula (III): 【Chemistry 47】 [In the formula, Each R ５ , R ６ , R ７ , R ８ , R ９ , R １０ and R １１ is independently H, halogen, fluoroalkyl, or perfluoroalkyl; X is -[OC(R ｈ R ｉ )-C(R ｊ R ｋ )] ｑ -O-[CR ｌ R ｍ ] ｚ -SO ３ H, and each R ｈ , R ｉ , R ｊ , R ｋ , R ｌ and R ｍ is independently H, halogen, fluoroalkyl, or perfluoroalkyl; q is 0 to 10; and z is 1 to 5.

27. The synthetic polymer has at least one sulfonic acid (—SO ３ 25. The charge transporting thin film of claim 24, which is a polyethersulfone containing one or more repeating units containing the moiety H).

28. The charge transporting thin film according to any one of claims 1 to 27, further comprising one or more amine compounds.

29. 29. The charge transporting thin film according to claim 28, wherein the amine compound comprises a tertiary alkylamine compound and an amine compound other than a tertiary alkylamine compound.

30. 30. The charge transporting thin film according to claim 29, wherein the amine compound other than a tertiary alkylamine compound is a primary alkylamine compound.

31. 31. The charge transporting thin film according to claim 30, wherein the primary alkylamine compound is at least one selected from the group consisting of ethylamine, n-butylamine, t-butylamine, n-hexylamine, 2-ethylhexylamine, n-decylamine, and ethylenediamine.

32. 31. The charge transporting thin film according to claim 30, wherein the primary alkylamine compound is 2-ethylhexylamine or n-butylamine.

33. A device comprising the charge transporting thin film according to any one of claims 1 to 32.

34. 34. The device of claim 33, wherein the charge transporting thin film is a hole injection layer or a hole transport layer.

35. 35. The device of claim 34 which is an organic electronic device.

36. 36. The device of claim 35, which is an organic light emitting diode (OLED).

Images