JP2018046002A - Solution for organic el, method of producing organic el device, and organic el device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solution for organic EL, which does not deteriorate the properties of the solution itself even if brought into contact with a structural member of a printing apparatus.SOLUTION: In a solution for organic EL, an organic EL contributing material is dissolved into the mixed solvent of two or more kinds of organic solvents which contain at least a first organic solvent and a second organic solvent. The coordinates (HSP coordinates) specified by Hansen solubility parameters of the first organic solvent are Hd in a range of 17.5-19.5 (J/cm), Hp in a range of 3.5-5.5 (J/cm), and Hh in a range of 3.5-5.5 (J/cm). The HSP coordinates of the second organic solvent are Hd in a range of 17.5-19.5 (J/cm), Hp in a range of 0-2.0 (J/cm), and Hh in a range of 0.5-2.5 (J/cm).SELECTED DRAWING: None

Description

  The present invention relates to an organic EL solution, an organic EL device manufacturing method, and an organic EL device.

  In recent years, research and development of organic electroluminescence (EL) devices, which are light-emitting devices using the electroluminescence phenomenon of solid fluorescent materials, have been progressing. An organic EL device has features such as high visibility because it emits light, and excellent impact resistance because it is a complete solid element. An organic EL device is constructed by laminating an organic layer including a light emitting layer that performs electroluminescence phenomenon by recombination of carriers (holes and electrons) between a pair of electrodes of a pixel electrode (anode) and a common electrode (cathode). The The organic layer is formed of an organic material, and includes a carrier injection layer, a carrier transport layer, a carrier blocking layer, and the like in addition to the light emitting layer.

  There exist a vapor deposition system and a coating system (for example, refer patent document 1) as an example of the manufacturing method of the said organic layer. In the application method, an organic material is dissolved in a solvent to form an ink (organic EL solution), and the ink is applied onto a substrate by a printing method (droplet discharge method) or the like. After application, the solvent is evaporated from the ink and dried to form an organic layer. Therefore, in the coating method, it is not necessary to perform the process in a vacuum vessel, which is preferable in terms of mass production.

  In addition, the organic EL solution used for manufacturing the organic EL device is usually mixed with two or more kinds of organic solvents (for example, see Patent Document 2). It is preferable in terms of the flatness of the film shape.

JP 2009-267299 A JP 2013-143324 A

  By the way, in the step of applying the ink onto the substrate by a printing method or the like, the ink comes into contact with the constituent members of the printing apparatus. In addition, the ink applied on the substrate comes into contact with another organic layer already formed on the substrate, a partition layer (bank component) for avoiding mixing with inks of different colors, or the like.

  However, the organic solvent contained in the ink includes an organic solvent that elutes a small amount of a component of the printing apparatus and degrades the printing apparatus. There are also organic solvents that dissolve other organic layers and partition layers to degrade the performance of other organic layers and partition layers. In addition, there are organic solvents that elute a trace amount of components of the printing apparatus, the organic layer, and the partition layer, thereby degrading the performance of the ink itself. Therefore, the ink is required not to deteriorate by dissolving or deteriorating the performance of the ink itself even if it contacts with the components of the printing apparatus, other organic layers or partition layers on the substrate, etc. ing.

  The subject of this invention is providing the solution for organic EL which does not degrade the performance of the solution itself, even if it contacts the component of a printing apparatus.

  The other subject of this invention is a manufacturing method of an organic EL device provided with the structure which pinched | interposed the organic layer containing a light emitting layer between two electrodes, Comprising: By apply | coating and drying using the said organic EL solution, The manufacturing method of the organic EL device including the process of forming the said organic layer is provided.

  Another object of the present invention is to provide an organic EL device in which the organic layer is formed by the method for producing the organic EL device.

According to one embodiment of the present invention, an organic EL solution in which an organic EL contributing material is dissolved in a mixed solvent of two or more organic solvents including at least a first organic solvent and a second organic solvent, The coordinates (HSP coordinates) defined by the Hansen solubility parameter of the first organic solvent are Hd in the range of 17.5 to 19.5 (J / cm ³ ) ^1/2 , 3.5 to 5.5 ( J ^/ cm ³⁾ Hp and 3.5 to 5.5 in ^1/2 of the range ^{(J /} cm ³⁾ is the Hh within ^1/2 of the range, HSP coordinates of the second organic solvent is 17. 5~19.5 ^{(J /} cm ³⁾ in the ^half of the range Hd, within the range of ^{0~2.0 (J / cm 3) 1/2} Hp and 0.5 to 2.5 (J / A solution for organic EL that is Hh in the range of cm ³ ) ^1/2 is provided.

FIG. 1 is a cross-sectional view of an organic EL display panel included in an organic EL device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a manufacturing process of the organic EL display panel shown in FIG. FIG. 3 is a top view at the time of manufacturing the organic EL display panel shown in FIG. FIG. 4 is a schematic block diagram showing a schematic configuration of an organic EL device including the organic EL display panel shown in FIG.

In the organic EL solution according to the embodiment of the present invention, the organic EL contributing material is dissolved in a mixed solvent of two or more organic solvents including at least the first organic solvent and the second organic solvent. The coordinates (HSP coordinates) defined by the Hansen solubility parameter of the first organic solvent are Hd in the range of 17.5 to 19.5 (J / cm ³ ) ^1/2 , 3.5 to 5.5 (J / ^{cm 3)} Hp and 3.5 to 5.5 in ^1/2 of the range ^{(J /} cm ³⁾ is the Hh within ^1/2 of the range. HSP coordinates of the second organic solvent is, 17.5~19.5 ^{(J /} cm ³⁾ in the ^half of the range Hd, Hp in the range of 0~2.0 ^{(J /} cm ^{3) 1/2} And Hh within a range of 0.5 to 2.5 (J / cm ³ ) ^1/2 .

The Hansen Solubility Parameter (HSP) is composed of three parameters: energy by London dispersion force (Hd), energy by dipole interaction (Hp), and energy by hydrogen bonding (Hh). The HSP is a vector quantity represented as (Hd, Hp, Hh), and is represented by plotting on a three-dimensional space (Hansen space) having the three parameters of the HSP as coordinate axes. The HSP can be expressed as HSP coordinates, for example. The unit of each parameter is (J / cm ³ ) ^1/2 . HSP is described, for example, in pages 1 to 26 of Hansen Solubility Parameters: A User's Handbook, Second Edition by Charles M. Hansen.

  Since the database of the HSPs of commonly used substances has been constructed, the HSP of the desired substance can be obtained by referring to the database. For a substance whose HSP is not registered in the database, the HSP can be calculated from the chemical structure of the substance by using computer software such as Hansen Solubility Parameters in Practice (HSPiP).

  The HSP of a mixture containing two or more substances is calculated as a vector sum of values obtained by multiplying the HSP of each substance by the volume ratio of each substance to the entire mixture.

The HSP coordinates of the first organic solvent according to the embodiment of the present invention are Hd in the range of 17.5 to 19.5 (J / cm ³ ) ^1/2 , 3.5 to 5.5 (J / cm ^3). ) Hp in the range of ^1/2 and Hh in the range of 3.5 to 5.5 (J / cm ³ ) ^1/2 .

  Examples of the first organic solvent are ethylphenyl acetate, m-tolyl acetate, o-tolyl acetate, o-methylbenzyl acetate, propylphenyl acetate, 2-phenylpropyl acetate, styryl acetate, methylphenyl acetate, methylphenylcarbyl Acetate, methyl benzyl acetate, 3-phenylpropyl acetate, allyl phenyl acetate, benzyl butyrate, o-cresyl isobutyrate, cresyl butyrate, p-cresyl isobutyrate, p-anisyl isobutyrate, methyl 4-phenylbutyrate, benzylpropionate, phenethylpropionate, styrylylpropionate, cinnamylpropionate, p-cresylpropionate, p-methylanisole, m-methyla Sole, o-methylanisole, 2,4-dimethylanisole, o-vinylanisole, 4-ethylanisole, phenylacetaldehyde ethylene acetal, benzaldehyde propylene acetal, 2- (α-methylbenzyl) -1,3-dioxolane, cinnamaldehyde Dimethyl acetal, o-diethoxybenzene, p-methoxystyrene, 2-ethoxynaphthalene, 4-allylanisole, 3,4-dimethoxystyrene, 1-ethoxynaphthalene, octylmethoxycinnam, 2,5-dimethoxystyrene, 2, 6-dimethoxystyrene, 1-methoxy-4-propoxybenzene, benzyl methyl ether, butyl phenyl ether, ethyl phenyl ether, benzyl ethyl ether, phenyl isopropyl ether, phenol Nylpropyl ether, allyl phenyl ether, phenyl vinyl ether, anethole, dihydroanethole, benzalacetone, phenylethylideneacetone, 2- (4-isopropylphenyl) propanal, 3- (4-isopropylphenyl) propanal and the like. The first organic solvent may be a mixed solvent of two or more types as long as it is an HSP within the above-described range. The present invention is not limited to such examples.

  The first organic solvent according to the embodiment of the present invention is preferably dimethylanisole.

The HSP coordinates of the second organic solvent according to the embodiment of the present invention are Hd in the range of 17.5 to 19.5 (J / cm ³ ) ^1/2 , 0 to 2.0 (J / cm ³ ) ^1. Hp in the range of ^{/ 2} and Hh in the range of 0.5 to 2.5 (J / cm ³ ) ^1/2 .

  Examples of the second organic solvent are mesitylene, cyclohexylbenzene, toluene, benzene, p-diethylbenzene, ethylbenzene, on-butyltoluene, 1,2-diethylbenzene, 1,2,3,4-tetramethylbenzene, 1, 2,3,5-tetramethylbenzene, 1,1-diphenylpentane, 1,1-diphenylhexane, 3- (1-methylethenyl) toluene, 1-methyl-3-propylbenzene, 1-methyl-4- (1 -Methylethyl) -2- (1-propenyl) benzene, pentamethylbenzene, isopropylbenzene, 1,2,4-trimethylbenzene, 2,2-diphenylpropane, 2-ethyldiphenylmethane, 1,4-dimethyltetralin, caramenene 1-butyl-1,2,3,4-tetrahydronaphthalene, 3-e Rudiphenylmethane, 1,1-diphenylpropane, 3-ethylbiphenyl, 3-methyldiphenylmethane, 1,1-diphenylbutane, 3,3′-dimethylbiphenyl, 3,3 ′, 4,4′-tetramethylbiphenyl, 3 , 3 ′, 5,5′-tetramethylbiphenyl, diethylbiphenyl, (S) -1,2-dihydro-4,7-dimethyl-1-isopropylnaphthalene, (S) -1,2-dihydro-1,6 -Dimethyl-4-isopropyl naphthalene etc. are mentioned. The second organic solvent may be a mixed solvent of two or more types as long as it is an HSP within the above-described range. The present invention is not limited to such examples.

  The second organic solvent according to the embodiment of the present invention is preferably diphenylpropane.

  In the organic EL solution according to the embodiment of the present invention, in addition to the first organic solvent and the second organic solvent, other solvents may be added as necessary within the range in which the object of the present invention is not hindered.

  The organic EL contributing material is an organic material that contributes to the organic EL, and is an organic EL material (light emitting material of R, G, and B), a carrier transport material (electron transport material, hole transport material), carrier injection property. Materials (electron-injecting materials, hole-injecting materials) and carrier-blocking materials (electron-blocking materials, hole-blocking materials).

  The organic EL contributing material according to the embodiment of the present invention is, for example, a light emitting material, a carrier transporting material, a carrier injecting material, or a carrier blocking material.

  Examples of the light emitting material are F8-co-F6 (copolymer of F8 (polydioctylfluorene) and F6 (polydihexylfluorene)), oxinoid compound, perylene compound, pyrrolopyrrole compound, naphthalene compound, anthracene compound, fluorene compound , Fluoranthene compound, tetracene compound, pyrene compound, coronene compound, quinolone compound and azaquinolone compound, pyrazoline derivative, pyrazolone derivative, rhodamine compound, chrysene compound, phenanthrene compound, cyclopentadiene compound, stilbene compound, diphenylquinone compound, styryl compound, butadiene compound , Dicyanomethylenepyran compound, dicyanomethylenethiopyran compound, fluorescein compound, pyrylium compound, thiapyrylium compound, serena Lilium compound, telluropyrylium compound, aromatic ardadiene compound, oligophenylene compound, thioxanthene compound, cyanine compound, acridine compound, metal complex of 8-hydroxyquinoline compound, metal complex of 2-bipyridine compound, Schiff base and group III metal Examples include fluorescent substances such as chain bodies, oxine metal complexes, and rare earth complexes. These compounds and complexes may be used alone or in combination. The present invention is not limited to such examples.

  Examples of hole transporting materials are triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives Fluorenone derivatives, hydrazone derivatives, stilbene derivatives, porphyrin compounds, aromatic tertiary amine compounds, styrylamine compounds, butadiene compounds, polystyrene derivatives, hydrazone derivatives, triphenylmethane derivatives, tetraphenylbenzine derivatives, and the like. These compounds and complexes may be used alone or in combination. Further, the hole transporting material may be used as an electron blocking material. The present invention is not limited to such examples.

Examples of the electron transporting material include compounds having a heterocycle such as a phenanthroline derivative, a pyridine derivative, a tetrazine derivative, and an oxadiazole derivative, or a metal complex such as a tris (8-hydroxyquinolinato) aluminum complex (Alq ₃ ). Is mentioned. Further, the electron transporting material may be used as a hole blocking material. These compounds and complexes may be used alone or in combination. Further, the hole transporting material may be used as an electron blocking material. The present invention is not limited to such examples.

  Examples of hole injecting materials include metal oxides such as MoOx (molybdenum oxide), WOx (tungsten oxide) or MoxWyOz (molybdenum-tungsten oxide) (x, y and z are positive numbers), metal nitriding Or metal oxynitride.

  Examples of the electron injecting material include alkali metals such as lithium and sodium, alkaline earth metals such as magnesium and calcium, alkali metals such as lithium fluoride and lithium oxide, or inorganic compounds of alkaline earth metals, 8-quinolinol lithium and the like And organometallic complexes having an alkali metal or alkaline earth metal as a central metal. The present invention is not limited to such examples.

  The organic EL solution according to the embodiment of the present invention does not deteriorate the performance of the solution itself even when it comes into contact with a constituent member of the printing apparatus. Specifically, the performance of the organic EL contributing material contained in the organic EL solution does not deteriorate even when the organic EL solution is in contact with the constituent member of the printing apparatus. In addition, even when the organic EL solution is in contact with another organic layer or the like already formed on the substrate, it does not dissolve and deteriorate, and the performance of the solution itself does not deteriorate. Therefore, the organic layer can be formed without degrading the performance by applying the organic EL solution according to the embodiment onto the substrate by a droplet discharge method or the like and drying the solution.

  An organic EL device manufacturing method according to an embodiment of the present invention is a method for manufacturing an organic EL device having a structure in which an organic layer including a light emitting layer is sandwiched between two electrodes, and the organic EL solution of the embodiment A step of forming the organic layer by applying and drying the film.

  Hereinafter, the manufacturing method of the organic EL device according to the embodiment will be described. First, the configuration of the organic EL display panel 1 formed by the manufacturing method will be described with reference to FIG. The organic EL display panel 1 is incorporated in the organic EL device according to the embodiment.

  FIG. 1 is a cross-sectional view of the organic EL display panel 1. FIG. 1 shows two pixels (six sub-pixels) of the organic EL display panel 1.

  The organic EL display panel 1 includes a TFT substrate 11 including a glass substrate, a TFT (thin film transistor) layer, a planarizing film layer, and the like, and a partition wall layer 12 formed on the TFT substrate 11. Note that thin film transistors and planarization films are not shown here because well-known structures are used. The film thickness of the partition wall layer 12 is about 1 μm, and the cross-sectional shape thereof is a forward tapered shape.

  In the sub-pixel region between the adjacent partition layers 12, an anode (first electrode) 13 made of a metal such as Al, a hole injection layer 14, and light emitting layers 15R, 15G, 15B made of a light emitting material ( Hereinafter, when there is no need for distinction, “light emitting layer 15” is collectively referred to. Further, an electron injection layer 16 that covers the partition wall layer 12 and the light emitting layer 15, a cathode (second electrode) 17 made of a transparent material such as ITO (Indium Tin Oxide), and a light transmission property such as SiN and SiON. A sealing layer 18 made of a material is sequentially laminated. In the organic EL display panel 1, a combination of three sub-pixels R, G, and B is one pixel. The emission color of the sub-pixel region is different from R, G, and B due to the difference in the light emitting material of the light emitting layer 15.

Next, a method for manufacturing the organic EL display panel 1 will be described with reference to FIGS.
2A to 2D are cross-sectional views showing the manufacturing process of the organic EL display panel 1, and FIG. 3 is a top view of FIG. In addition, the AA 'cross section in FIG. 3 is (b) of FIG.

  As shown in FIG. 2A, first, a substrate 10 including a TFT substrate 11, a partition wall layer 12, an anode 13, and a hole injection layer 14 is prepared.

  As shown in FIG. 2B, in all the sub-pixel regions on the substrate 10, the concave portions surrounded by the partition wall layer 12 are used for organic EL, which is a material of the light emitting layer 15 by a printing method using an ink jet method. The light emitting layer 15 is formed by applying and drying the solution. As shown in FIG. 3, the partition wall layer 12 surrounds the light emitting layer 15. Further, the region where the light emitting layer 15 is visible corresponds to each sub-pixel region. In a general 20-inch organic EL display panel, when 1280 × 768 pixels are arranged at an equal distance, the size of the sub-pixel region is about (64 μm × 234 μm).

  As shown in FIG. 2C, an electron injection layer 16 and a cathode 17 are formed so as to cover the partition layer 12 and the light emitting layer 15.

  As shown in FIG. 2D, when the sealing layer 18 is formed on the cathode 17, the organic EL display panel 1 is completed.

  In addition, about the cathode 17 and the sealing layer 18, the general member and formation technique in a well-known organic light-emitting device technique are used.

Next, the configuration of the organic EL device 40 according to the embodiment will be described with reference to FIG.
FIG. 4 is a schematic block diagram illustrating a schematic configuration of the organic EL device 40 including the organic EL display panel 1.

  As shown in FIG. 4, the organic EL display panel 1 is electrically connected to a drive circuit 31, and the drive circuit 31 is controlled by a control circuit 32. The electrical connection of the organic EL display panel 1 is as known. Thus, the organic EL device 40 provided with the organic EL display panel 1 can be manufactured. In other words, the organic layer of the organic EL device is formed by the manufacturing method described above.

  Hereinafter, the present invention will be described with reference to examples.

[Preparation of organic solvent]
Organic solvents A to F shown in Table 1 were prepared. The HSP coordinates of each organic solvent are also shown.

[Preparation of organic EL contributing material (solute)]
An anthracene-based luminescent material was prepared as a solute.

[Preparation of solution for organic EL]
Each solvent mixture of the combinations shown in Table 2 and the solute are stirred in an atmosphere at a temperature of 60 ° C. and a shaker at 100 rpm for 24 hours to dissolve the solute, and 2.0 wt% for organic EL Solutions (No. 1 to No. 13) were prepared. The mixing ratio of the two organic solvents was 50:50 (weight% ratio).

〔Evaluation method〕
No. prepared in this way. 1-No. 13 organic EL solutions were set in a printing apparatus, ejected from the printing apparatus, and contacted with components of the printing apparatus, and those not contacted with liquid were prepared. Subsequently, after deaeration treatment, the fluorescence quantum yield (PLQE) of each organic EL solution was measured using a fluorescence quantum yield measuring apparatus.

Next, no. 1-No. The PLQE change rate (%) of the organic EL solution of No. 13 is expressed by the following formula: [PLQE change rate] = ([PLQE of the organic EL solution in contact with the components of the printing apparatus] / [not in contact with liquid] PLQE of organic EL solution]) x 100%
Calculated by

No. 1-No. The PLQE change rate of 13 organic EL solutions was evaluated in three stages. As a result of the evaluation, a>b> c, and a has a PLQE change rate of 90% or more, and the performance of the organic EL solution is not deteriorated or the degree of deterioration is small even if it is deteriorated. b has a PLQE change rate of 60% or more and less than 90%. c has a PLQE change rate of less than 60%, and the degree of deterioration of the organic EL solution is large. The results are shown in Table 2.

〔result〕
No. in Table 2 As shown in 1, 2, 5, and 6, all the solutions for organic EL containing the mixed solvent of the first organic solvent and the second organic solvent have a PLQE change rate exceeding 100%. In other words, it can be seen that the performance of the organic EL solution according to the embodiment does not deteriorate even when the organic EL solution is in contact with the constituent member of the printing apparatus.

  In addition, the organic EL solution that does not include either the first organic solvent or the second organic solvent, or the first organic solvent and the second organic solvent, has a PLQE change rate of less than 100%. As a comparative example, it was found that when the E and F solvents that do not satisfy the HSP of the first organic solvent and the second organic solvent were used, the PLQE change rate decreased.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and does not limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

1 Organic EL Display Panel 11 TFT Substrate 12 Partition Layer 13 Anode (First Electrode)
14 Hole injection layer 15 Light emitting layer 16 Electron injection layer 17 Cathode (second electrode)
18 Sealing layer 40 Organic EL device

Claims (6)

An organic EL solution in which an organic EL contributing material is dissolved in a mixed solvent of two or more organic solvents including at least a first organic solvent and a second organic solvent,
The coordinates (HSP coordinates) defined by the Hansen solubility parameter of the first organic solvent are Hd in the range of 17.5 to 19.5 (J / cm ³ ) ^1/2 , 3.5 to 5.5 ( J / cm ³ ) Hp in the range of ^1/2 and Hh in the range of 3.5 to 5.5 (J / cm ³ ) ^1/2 ,
The HSP coordinates of the second organic solvent is, 17.5~19.5 ^{(J /} cm ³⁾ in the ^half of the range ^{Hd, 0~2.0 (J / cm 3} ) in the ^half of the range Solution for organic EL which is Hh in the range of Hp and 0.5-2.5 (J / cm < ³ >) < ^1/2 >.   The organic EL solution according to claim 1, wherein the first organic solvent is dimethylanisole.   The organic EL solution according to claim 1, wherein the second organic solvent is diphenylpropane.   The organic EL solution according to any one of claims 1 to 3, wherein the organic EL contributing material is a light emitting material, a carrier transporting material, a carrier injecting material, or a carrier blocking material.   It is a manufacturing method of an organic EL device provided with the structure which pinched | interposed the organic layer containing a light emitting layer between two electrodes, Comprising: It apply | coats using the solution for organic EL of any one of Claims 1-4, The manufacturing method of the organic EL device including the process of forming the said organic layer by drying.   It is an organic EL device provided with the structure which pinched | interposed the organic layer containing a light emitting layer between two electrodes, Comprising: The said organic layer is apply | coated using the solution for organic EL of any one of Claims 1-4. An organic EL device formed by drying.

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