JP2008130654A - Organic electroluminescent device, manufacturing method therefore, and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent device which lowers the viscosity of a solution to ensure a stable discharge performance and prevents a deterioration in light emission characteristics and a reduction in the device life when a hole injection layer is formed by a wet film formation method. <P>SOLUTION: The organic electroluminescent device includes a functional layer 7 composed of two or more layers including the hole injection layer 4 and a light emission layer 5, and a pair of electrodes 3 and 8 which hold the functional layer 7 between them. The hole injection layer 4 is formed by disposing a first precursor and a second precursor on a basic substance 2, on which the electrode 3 is formed, and polymerizing the first and second precursors. The first precursor (first liquid material 4a containing the first precursor) is a monomer or an oligomer having an epoxy group, and the second precursor (second liquid material 4b containing the second precursor) is a monomer or an oligomer having a thermal bridging functional group that polymerizes with the epoxy group. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to an organic electroluminescence device, a method for producing an organic electroluminescence device, and an electronic device, and more particularly to a compound for an organic electroluminescence device produced by a wet film forming method and a production technique thereof.

  In recent years, an organic electroluminescence device using an organic electroluminescence element as a pixel has been developed. Organic electroluminescence devices are capable of high-speed response with high brightness and low power consumption, and are expected to be applied to full-color displays and the like because of the variety of organic compounds that can be easily multicolored. . In the following description, “electroluminescence” is abbreviated as “EL”.

  An organic EL element has a structure in which at least one organic thin film including a light emitting layer is sandwiched between a pair of upper and lower electrodes. When a voltage is applied to the organic EL element, holes are injected from the anode side and electrons are injected from the cathode side into the light emitting layer, and the two recombine to cause a light emission phenomenon. Further, from the viewpoint of the element structure, a configuration in which a hole injection layer is disposed between the anode and the light emitting layer is widely adopted in order to improve the light emission efficiency and durability.

  Here, the organic molecules forming the organic thin film are roughly classified into low molecular weight systems and high molecular weight systems. When organic molecules are low molecular weight, the organic thin film is formed mainly by vacuum deposition. When high molecular weight, the organic thin film is mainly dissolved or dispersed in a solvent and then wet coating such as spin coating or ink jet. It is common to form an organic thin film.

For example, when the hole injection layer is formed of a polymer material, a polythiophene derivative or a polyaniline derivative is used as the hole injection material, which is diluted with a solvent and applied onto the substrate. On the other hand, when the hole injection layer is formed of a low molecular material, a triphenylamine derivative is used as the hole injection material, and this is formed on the substrate by vacuum deposition. In particular, a droplet discharge method such as an ink jet method is very effective as a method for manufacturing an organic EL device because organic thin film materials can be easily and finely patterned without being wasted. Refer to Patent Documents 1 and 2 for a method of forming a hole injection material by a droplet discharge method.
JP 2002-231447 A Japanese Patent Laid-Open No. 2005-100954

  In the case of forming a hole injection material by a droplet discharge method, the hole injection material is dissolved or dispersed in a solvent and then discharged. In this case, there is an optimum range for the viscosity of the solution, and stable and uniform film formation is possible by discharging within this range. For example, in Patent Document 1, the solution viscosity that can be stably discharged without causing clogging in the discharge nozzle of the droplet discharge head is preferably about 2 to 20 cps, particularly about 7 to 10 cps in a 1 to 3 wt% solution. It is listed as good.

  However, some of the hole injection materials used have high viscosity, and stable ejection may not be obtained. In addition, a method of diluting a high-viscosity hole injection material with a solvent and reducing the viscosity is also conceivable, but in this case, the concentration of the hole injection material is reduced, so that the desired film thickness is As a result, it becomes necessary to perform multiple coating, resulting in a problem that the production efficiency is lowered and the amount of the solvent to be used is increased.

  As means for solving this problem, Patent Document 2 discloses a method in which EDOT, which is a monomer of PEDOT, and a polymerization catalyst such as iron chloride III are discharged by a droplet discharge method and polymerized on a substrate. However, when the monomer is polymerized with the polymerization catalyst, the polymerization catalyst remains in the hole injection layer, which may cause problems such as adversely affecting the light emission characteristics and reducing the lifetime of the organic EL device.

  The present invention has been made in view of such circumstances, and when forming a hole injection layer by a wet film formation method, the viscosity of the solution can be lowered to ensure stable ejection performance, and the light emission characteristics are deteriorated. Another object of the present invention is to provide an organic electroluminescence device and a method for manufacturing the same that can prevent a decrease in service life. It is another object of the present invention to provide an electronic device with high reliability and excellent light emission characteristics by including such an organic electroluminescence device.

  In order to solve the above problems, an organic electroluminescence device of the present invention includes a functional layer composed of two or more layers including a hole injection layer and a light emitting layer, and a pair of electrodes sandwiching the functional layer, The hole injection layer has a first precursor that is a monomer or oligomer having an epoxy group and a monomer having a thermally crosslinkable functional group that causes a polymerization reaction with the epoxy group on a substrate on which one of the electrodes is formed. It is formed by arranging a second precursor that is an oligomer and polymerizing the first precursor and the second precursor on the substrate. According to this configuration, in order to form the hole injection layer by the polymerization reaction of the low-viscosity monomer or oligomer, the first precursor and the second precursor containing each monomer or oligomer were discharged by the droplet discharge method. Even in this case, stable discharge performance can be secured. In addition, since the hole injection layer is cross-linked without a polymerization catalyst by an epoxy reaction, problems such as deterioration in light emission characteristics due to catalyst impurities and reduction in the lifetime of the organic EL element do not occur. Further, since the obtained hole injection layer is an epoxy resin having high solvent resistance, even when other layers such as a light emitting layer are formed on the hole injection layer by a wet film formation method, Re-dissolution does not occur. Thereby, an organic EL device having excellent reliability can be provided.

  In the present invention, it is desirable that the second precursor is a monomer or oligomer containing an amino group, a hydroxyl group, or both as the thermally crosslinkable functional group. According to this configuration, a hole injection layer having high solvent resistance can be formed.

  In the present invention, it is desirable that either the first precursor or the second precursor contains any of a triphenylamine derivative, a carbazole derivative, a pyrrole derivative, or a thiophene derivative. Specifically, it is desirable that either the first precursor or the second precursor includes any of the following formulas (1) to (11). According to this configuration, a hole injection layer with high hole injection efficiency can be formed.

  In the present invention, in the above formulas (2) to (11), the integer n representing the number of monomer or oligomer units is preferably 1 to 20, and particularly preferably 1 to 10. According to this configuration, since the viscosity of the solution becomes small, it is possible to provide a solution having high discharge performance when discharged by the droplet discharge method.

In the present invention, in the formulas (2) to (11), the functional group R, R ₁ , R ₂ , or R ₃ is preferably an alkyl group. According to this configuration, a monomer or oligomer having high solubility in a solvent can be provided.

In the present invention, the formula (4), (5), (8) - (11), the functional group _{Q 1} is N-T1, it is desirable that the T1 is an alkyl group. According to this configuration, a monomer or oligomer having high solubility in a solvent can be provided.

In the present invention, the formula (5), (9), (11), the functional group _{Q 2} are N-T2, it is desirable that the T2 is an alkyl group. According to this configuration, a monomer or oligomer having high solubility in a solvent can be provided.

  The method for producing an organic electroluminescent device of the present invention is a method for producing an organic electroluminescent device comprising a functional layer composed of two or more layers including a hole injection layer and a light emitting layer, and a pair of electrodes sandwiching the functional layer. In the method, the step of forming the hole injection layer includes: a first precursor that is a monomer or an oligomer having an epoxy group on a substrate on which one of the electrodes is formed; and a polymerization reaction with the epoxy group. A step of disposing a second precursor which is a monomer or oligomer having a thermally crosslinkable functional group to be formed by a droplet discharge method, and polymerizing the first precursor and the second precursor on the substrate. It is characterized by. According to this method, in order to form the hole injection layer by a polymerization reaction of monomers or oligomers having a low viscosity, the first precursor and the second precursor containing the respective monomers or oligomers were discharged by a droplet discharge method. Even in this case, stable discharge performance can be secured. In addition, since the hole injection layer is cross-linked without a polymerization catalyst by an epoxy reaction, problems such as deterioration in light emission characteristics due to catalyst impurities and reduction in the lifetime of the organic EL element do not occur. Further, since the obtained hole injection layer is an epoxy resin having high solvent resistance, even when other layers such as a light emitting layer are formed on the hole injection layer by a wet film formation method, Re-dissolution does not occur. Thereby, an organic EL device having excellent reliability can be provided.

  In the present invention, it is desirable to polymerize the first precursor and the second precursor disposed on the substrate by heating. According to this method, the polymerization reaction between the first precursor and the second precursor is promoted, and the production efficiency can be improved.

  The electronic apparatus of the present invention includes the organic electroluminescence device of the present invention described above or the organic electroluminescence device manufactured by the method of manufacturing the organic electroluminescence device of the present invention described above. According to this configuration, an electronic device with high reliability and excellent light emission characteristics can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. This embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, an actual structure and a scale, a number, and the like in each structure are different.

  FIG. 1 is a schematic configuration diagram of an organic EL device EL1 which is an embodiment of the organic EL device of the present invention. The organic EL device EL1 has a substrate body 2 made of glass, quartz, plastic, or the like as a base, and an anode 3 as a first electrode, a hole injection layer 4, a light emitting layer 5, and a second electrode on the base 2. A cathode 8 is provided. The hole injection layer 4 and the light emitting layer 5 are formed of an organic material, and the hole injection layer 4 and the light emitting layer 5 form a functional layer 7. The functional layer 7 is sandwiched between the first electrode 3 and the second electrode 8, and the organic EL element 9, which is a light emitting element, is formed by the first electrode 3, the functional layer 7, and the second electrode 8. ing.

  A wiring for applying a drive voltage is connected to the first electrode 3 and the second electrode 8. Holes from the first electrode 3 and electrons from the second electrode 8 are injected into the light emitting layer 5 through the wiring. The holes and electrons injected into the light emitting layer 5 move through the light emitting layer 5 and recombine. The energy released during the recombination generates excitons, and when the excitons return to the ground state, energy is emitted in the form of fluorescence or phosphorescence. The light emitted from the organic EL element 9 is emitted from the base 2 made of a glass substrate or the like and taken out to the outside (bottom emission method). When the second electrode 8 is formed of a transparent conductive film such as ITO, light emitted from the organic EL element 9 can be extracted from the second electrode 8 side (top emission method). In the following description, electrons and holes injected into the light emitting layer 4 may be referred to as carriers.

  Here, the hole injection layer 4 contains any of a triphenylamine derivative, a carbazole derivative, a pyrrole derivative, or a thiophene derivative. Specifically, what contains the structure in any one of following formula (1)-(11) is preferable.

  The hole injection layer 4 comprises a first precursor that is a monomer or oligomer having an epoxy group and a second precursor that is a monomer or oligomer having a thermally crosslinkable functional group that causes a polymerization reaction with the epoxy group. It is formed by arranging the first precursor and the second precursor on the top (more specifically, on the first electrode 3) and polymerizing the first precursor and the second precursor. As the second precursor, a monomer or oligomer containing an amino group, a hydroxyl group or both of them as the thermally crosslinkable functional group can be used. For example, the first precursor has a structure represented by the following formula (12), and the second precursor has a structure represented by any of the following formulas (13) to (15), for example. ing.

In the above formulas (2) to (11), the integer n representing the number of monomer or oligomer units is preferably 1 to 20, and particularly preferably 1 to 10. According to this configuration, since the viscosity of the solution becomes small, it is possible to provide a solution having high discharge performance when discharged by the droplet discharge method. In the above formulas (2) to (11), the functional group R, R ₁ , R ₂ , or R ₃ is preferably an alkyl group. According to this configuration, a monomer or oligomer having high solubility in a solvent can be provided. Furthermore, in the above formulas (4), (5), (8) to (11), the functional groups T1 and T2 are preferably alkyl groups. According to this configuration, a monomer or oligomer having high solubility in a solvent can be provided.

  The light emitting layer 5 includes a known light emitting material capable of emitting fluorescence or phosphorescence. Specifically, (poly) fluorene derivative (PF), (poly) paraphenylene vinylene derivative (PPV), polyphenylene derivative (PP), polyparaphenylene derivative (PPP), polyvinyl carbazole (PVK), polythiophene derivative, polymethyl Polysilanes such as phenylsilane (PMPS) are preferably used. In addition, these polymer materials include polymer materials such as perylene dyes, coumarin dyes, rhodamine dyes, rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, Nile red, coumarin 6, and quinacridone. It can also be used by doping a low molecular weight material such as. Alternatively, a low molecular material such as carbazole (CBP) can be doped with these low molecular dyes to form a light emitting layer. Tris-8-quinolinolato aluminum complex (Alq3) can also be added as an electron transporting layer as part of the light emitting layer.

  Next, a manufacturing method of the organic EL device EL1 will be described with reference to FIG. First, as shown in FIG. 2A, a first liquid material 4a containing a first precursor and a second liquid material 4b containing a second precursor are formed on a base 2 on which a first electrode 3 is formed. Are sequentially arranged by a droplet discharge method. Then, the hole injection layer 4 shown in FIG. 2B is formed by polymerizing the first precursor and the second precursor on the substrate 2.

  The first precursor and the second precursor have the structures shown in the above formulas (12) to (15). In the present embodiment, a first precursor having a structure represented by the following formula (16) is used, and a second precursor having a structure represented by the following formula (17) is used. And hole injection layer 4 is formed by polymerizing these. The chemical structure obtained by polymerization of the formula (16) and the formula (17) cannot be clearly grasped even with the current analytical technique, but as an example, it is presumed to have the structure represented by the following formula (18) Is done. The polymerization reaction is performed by heating the substrate 2 as necessary. Thereby, the polymerization reaction of the first precursor and the second precursor can be promoted.

  Here, the first precursor represented by the above formula (16) is a known material. The method for synthesizing the second precursor represented by the above formula (17) is as follows. First, under a nitrogen atmosphere, a material (10 mmol) represented by the following formula (19) and tetrahydrofuran (30 ml) were placed in a Schlenk tube, stirred at −78 ° C. for 30 minutes, and then NBS (10 mmol) was added dropwise.

  After dropping, the mixture was gradually returned to room temperature and stirred overnight. The solution was concentrated and the residue was washed with water and cold methanol. Recrystallization from chloroform gave a white solid represented by the following formula (20) in a yield of 64%.

A material represented by the following formula (21) in which the material (6 mmol) of the above formula (20) is dissolved in 30 ml of acetonitrile and 5 ml of dimethylaminopyridine, and (Boc) ₂ O (7.2 mmol) is added to protect the amino group. Was obtained in 90%.

  The material (5 mmol) represented by the above formula (21) was dissolved in 30 ml of tetrahydrofuran and stirred at −78 ° C. Then, a 2.6 Mn-butyllithium hexane solution (10 mmol) was added dropwise at −78 ° C. Stir at temperature. Then, 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (10 mmol) was added at −78 ° C., and after slowly returning to room temperature, the mixture was stirred overnight. After stopping the reaction with water and extracting three times with diethyl ether, the organic layer was dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain a crude product. The crude product was purified by silica column chromatography (developing solvent: ethyl acetate) and recrystallized from methanol to obtain 80% of a white solid represented by the following formula (22).

In a Schlenk tube under a nitrogen atmosphere, a material (4 mmol) represented by the above formula (22), a material (4 mmol) represented by the following formula (23), Pd (PPh ₃ ) ₄ (0.04 mmol), 10 ml of toluene, a phase transfer catalyst. Aliquat 336 was added and stirred for 30 min.

Then degassed 2MK ₂ CO ₃ (1 ml) was added and reacted at 80 ° C. for 24 hours. After the reaction solution was extracted three times with diethyl ether, the organic layer was dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain a crude product. Recrystallization from chloroform yielded a white solid represented by the following formula (24) in a yield of 82%.

  The material of the above formula (24) was dissolved in THF, an appropriate amount of trifluoroacetic acid was added to remove the Boc group, and a material (second precursor) represented by the above formula (17) was obtained in a yield of 90%. Identification was performed by 1H-NMR, FAB-Mass, and FT-IR.

  When the second precursor is manufactured as described above, the droplet discharge head of the droplet discharge apparatus is filled with a solution (first liquid material 4a) in which the first precursor is dissolved in DMF, and the nozzle of the droplet discharge head is filled. The first liquid material 4a, whose liquid amount per droplet is controlled, is discharged onto the first electrode 3 from the droplet discharge head while the droplet discharge head and the substrate 2 are moved relative to each other. . Here, since the first precursor is a monomer or oligomer having a low molecular weight, the first liquid material 4a in which the first precursor is dissolved or dispersed is a liquid material having a low viscosity. Therefore, when discharging onto the substrate 2 by the droplet discharge head, the liquid material has good discharge performance.

  Next, the droplet discharge head of the droplet discharge device is filled with a solution (second liquid material 4b) in which the second precursor is dissolved in DMF, and the nozzle of the droplet discharge head is made to face the substrate 2 so that the liquid is discharged. While the droplet discharge head and the substrate 2 are relatively moved, the second liquid material 4b in which the amount of liquid per droplet is controlled from the droplet discharge head is changed to the first liquid material 4a discharged onto the first electrode 3. Dispense over the top. Here, since the second precursor is a monomer or oligomer having a low molecular weight, the second liquid material 4b in which the second precursor is dissolved or dispersed is a liquid material having a low viscosity. Therefore, when discharging onto the substrate 2 by the droplet discharge head, the liquid material has good discharge performance.

  When the second precursor is placed on the first precursor as described above, the epoxide of the first precursor and the amino group of the second precursor react with each other at room temperature / normal pressure or under heating / normal pressure, and polymerization occurs. Progresses. Then, when left for a certain period of time, an epoxy resin having the hole injection / transport unit shown in the above formula (18) is formed.

  As the monomer or oligomer of the hole injection / transport layer material used here, not only an amine skeleton derivative such as triphenylamine but also a thiophene derivative, a pyrrole derivative, and a phenyl derivative can be used. The intended polymer here is an inductive polymer. These solvents include N-methylpyrrolidone (NMP), dimethylformamide (DMF), hexamethylphossolamide (HMPA), dimethyl sulfoxide (DMSO), 1,3-dimethyl-2-imidazolidinone (DMI). ) And derivatives thereof, aliphatic and aromatic ether derivatives, and the like.

  Subsequently, the hole injection layer 4 is formed by drying the polymerized epoxy resin film and evaporating the polar solvent contained in the epoxy resin film. This drying process is performed, for example, in a nitrogen atmosphere at a room temperature and a pressure of about 133.3 Pa (1 Torr). After the drying treatment, it is preferable to remove the polar solvent and water remaining in the hole injection layer 4 by performing a heat treatment in nitrogen, preferably in vacuum, at 200 ° C. for about 10 minutes.

  When the hole injection layer 4 is formed as described above, the light emitting layer 5 is formed on the hole injection layer 4 as shown in FIG. As a method for forming the light emitting layer 5, a known wet film forming method represented by a spin coating method, a droplet discharge method, or the like can be used. Specifically, the polymer light-emitting material is dissolved or dispersed in an organic solvent, and disposed on the substrate 2 (more specifically, on the hole injection layer 4) by a spin coating method or a droplet discharge method. It can be formed by drying. The epoxy resin film (hole injection layer 4) represented by the above formula (18) is presumed to have a three-dimensional network structure, and is generally insoluble in an organic solvent. Even when the solution is discharged, the hole injection layer 4 is not redissolved by the solvent of the polymer light emitting material.

  Then, when the hole injection layer 4 and the light emitting layer 5 are formed by the above-described steps, a second electrode 8 is formed on the light emitting layer 5 as shown in FIG. A sealing member is disposed on the surfaces of the light emitting layer 4 and the light emitting layer 4 to perform a sealing process. Thus, the organic EL element 9 is completed.

  As described above, in this embodiment, the hole injection layer is formed by a polymerization reaction of a monomer or oligomer having a low viscosity. Therefore, stable discharge performance can be ensured even when the first precursor and the second precursor containing each monomer or oligomer are discharged by the droplet discharge method. For example, in the case of this embodiment, it is easy to suppress the viscosity of the first liquid material 4a and the second liquid material 4b within the range of 2 to 20 Ps, and stable discharge from the droplet discharge head is possible. Further, since the hole injection layer 4 is cross-linked without an polymerization catalyst by an epoxy reaction, problems such as deterioration of light emission characteristics due to catalyst impurities and reduction of the lifetime of the organic EL element 9 do not occur. In addition, since the obtained hole injection layer 4 is an epoxy resin having high solvent resistance, even when other layers such as the light emitting layer 5 are formed on the hole injection layer 4 by a wet film formation method, Re-dissolution of the injection layer 4 does not occur. Thereby, the organic EL device EL1 having excellent reliability can be provided.

[Example]
Next, an example of this embodiment will be described. First, a first precursor having a structure represented by formula (16) and a second precursor having a structure represented by formula (17) are formed on a substrate with a layer thickness of 50 nm to 60 nm by a droplet discharge method, followed by drying. By processing and evaporating the polar solvent contained in the epoxy resin film, a hole injection layer was formed. This drying process was performed in a nitrogen atmosphere at room temperature and a pressure of about 133.3 Pa (1 Torr). Moreover, after the drying process, it heated at 200 degreeC for about 10 minutes in the vacuum.

Next, poly [(9,9-dioctylfluorenyl-2,7-diyl) -co- (1,4-benzo- {2,1 ′, 3} -thiadiazole) is formed on the hole injection layer. ] (ADS133YE manufactured by ADS) as a 1.8 wt% trimethylbenzene solution, a layer having a layer thickness of 60 nm to 80 nm was formed by a droplet discharge method, and then subjected to a baking treatment at 130 ° C. for 30 minutes in a nitrogen atmosphere. A light emitting layer was formed. At this time, the hole injection layer was not dissolved in the organic solvent in which the light emitting material was dissolved. Then, under a vacuum of 10 ⁻⁶ Torr (1.33 × 10 ⁻⁴ Pa), a 4 nm thick LiF layer, a 10 nm thick Ca layer and a 200 nm thick Al layer are stacked by vacuum deposition. Thus, a cathode layer was formed.

[Comparative example]
Poly [(9,9-dioctylfluorenyl-2,7-diyl) -co- (1,4-benzo- {2,1 ′, 3} -thiadiazole without forming a hole injection layer on the substrate )] (ADS133YE manufactured by ADS) was formed into a 1.8 wt% trimethylbenzene solution by a droplet discharge method to form a layer having a thickness of 60 nm to 80 nm, and then subjected to a baking treatment at 130 ° C. for 30 minutes in a nitrogen atmosphere. A light emitting layer was formed. Then, under a vacuum of 10 ⁻⁶ Torr (1.33 × 10 ⁻⁴ Pa), a 4 nm thick LiF layer, a 10 nm thick Ca layer and a 200 nm thick Al layer are stacked by vacuum deposition. Thus, a cathode layer was formed.

Next, the emission spectrum was measured about the organic EL element of the Example and comparative example which were manufactured in this way. As a result, an emission spectrum of about 560 nm was obtained in the organic EL element of the example, and an emission spectrum of about 540 nm was obtained in the organic EL element of the comparative example. Next, the organic EL elements of Examples and Comparative Examples were driven at a constant current with an initial luminance of 100 cd / cm ² , and current efficiency and half-life of luminance were measured. As a result, the results shown in Table 1 were obtained. From Table 1, it was found that the results superior to the comparative examples were obtained in the examples.

[Image forming apparatus]
Next, an image forming apparatus which is a first embodiment of an electronic apparatus including the organic EL device of the present invention will be described. FIG. 3 is a schematic configuration diagram illustrating an image forming apparatus 100 including an organic EL device as a line head.

  The image forming apparatus 100 includes a photosensitive drum 16 as an image carrier in the vicinity of the travel path of the transfer medium 22. Around the photosensitive drum 16, an exposure device 15, a developing device 18, and a transfer roller 21 are sequentially arranged along the rotation direction of the photosensitive drum 16 (indicated by an arrow in the drawing). The photosensitive drum 16 is rotatably provided around the rotation shaft 17, and a photosensitive surface 16 </ b> A is formed on the outer peripheral surface of the photosensitive drum 16 at the central portion in the rotation axis direction. The exposure device 15 and the developing device 18 are arranged in a long axis shape along the rotation shaft 17 of the photosensitive drum 16, and the width in the long axis direction substantially coincides with the width of the photosensitive surface 16A.

  In this image forming apparatus 100, first, in the process of rotating the photosensitive drum 16, the surface of the photosensitive drum 16 (photosensitive surface 16 </ b> A) is positive (for example, positive) by a charging device (not shown) provided on the upstream side of the exposure device 15. Then, the exposure device 15 exposes the surface of the photosensitive drum 16 to form an electrostatic latent image LA on the surface. Further, the toner (developer) 20 is applied to the surface of the photosensitive drum 16 by the developing roller 19 of the developing device 18, and the toner image corresponding to the electrostatic latent image LA is formed by the electric attractive force of the electrostatic latent image LA. It is formed. The toner particles are positively (+) charged.

  After the toner image is formed by the developing device 18, the toner image comes into contact with the transfer medium 22 by further rotation of the photosensitive drum 16, and the transfer roller 21 has a polarity opposite to that of the toner particles of the toner image from the back surface of the transfer medium 22. Charge (here, negative (−) charge) is applied, and accordingly, toner particles forming a toner image are attracted from the surface of the photosensitive drum 16 to the transfer medium 22, and the toner image is transferred to the surface of the transfer medium 22. Is transcribed.

  The exposure apparatus 15 includes a line head 1 having a plurality of organic EL elements 9 and an imaging optical element 12 having a plurality of lens elements 13 for imaging the light L emitted from the line head 1 at an erecting equal magnification. I have. The line head 1 and the imaging optical element 12 are held by a head case (not shown) while being aligned with each other, and are fixed on the photosensitive drum 16.

  The line head 1 includes a light emitting element array 10 in which a plurality of organic EL elements 9 are arranged along the rotation axis 17 of the photosensitive drum 16, and a drive element group including a drive element (not shown) that drives the organic EL elements 9. And a control circuit group 11 for controlling driving of these drive elements (drive element group). The organic EL element 9, the drive element group, and the control circuit group 11 are integrally formed on a long and thin element substrate (base) 2.

  The imaging optical element 12 is arranged (arranged) in a zigzag pattern in which the lens elements 13 having the same configuration as the SELFOC (registered trademark) lens element manufactured by Nippon Sheet Glass Co., Ltd. are arranged along the rotation axis 17 of the photosensitive drum 16. A lens element array 14 is provided.

  In this image forming apparatus 100, the organic EL element 9 formed on the line head 1 has the structure of the light emitting element of the present invention described above. Therefore, the image forming apparatus has high emission luminance and no exposure failure occurs.

[Organic EL display device]
Next, an organic EL display device that is a second embodiment of an electronic apparatus including the organic EL device of the present invention will be described. FIG. 4 is a schematic configuration diagram of an organic EL display device 200 including organic EL elements as pixels in a matrix.

  The organic EL display device 200 includes a circuit element unit 30 including a thin film transistor as a circuit element, a pixel electrode (first electrode) 3 serving as an anode, an organic functional layer 7 including a light emitting layer, and a counter electrode serving as a cathode. (Second electrode) 8, a sealing portion 32, and the like are provided.

  For example, a glass substrate is used as the substrate 2. As a substrate in the present invention, in addition to a glass substrate, various known substrates used for electro-optical devices and circuit substrates such as a silicon substrate, a quartz substrate, a ceramic substrate, a metal substrate, a plastic substrate, and a plastic film substrate are applied. The

  On the base 2, a plurality of pixel areas A as light emitting areas are arranged in a matrix, and when performing color display, for example, corresponding to each color of red (Red), green (Green), and blue (Blue). The pixel area A to be formed is formed in a predetermined arrangement. In each pixel region A, a pixel electrode 3 is arranged, and in the vicinity thereof, a signal line 42, a common power supply line 43, a scanning line 41, a scanning line for other pixel electrodes (not shown), and the like are arranged. As the planar shape of the pixel region A, an arbitrary shape such as a circle or an oval can be applied in addition to the rectangle shown in the figure.

  The sealing portion 32 prevents water and oxygen from entering and prevents the counter electrode 8 or the organic functional layer 7 from being oxidized, and includes a sealing substrate (or sealing can) 34 bonded to the base 2. The sealing substrate 34 is made of glass, metal, or the like, and the base 2 and the sealing substrate 34 are bonded together with a sealing agent. A desiccant is disposed inside the substrate 2, and an inert gas filling layer 33 filled with an inert gas is formed in a space formed between the substrates.

  In the pixel region A, a first thin film transistor 44 for switching in which a scanning signal is supplied to the gate electrode through the scanning line 41 and a holding for holding an image signal supplied from the signal line 42 through the thin film transistor 44. The capacitor cap, the driving second thin film transistor 45 to which the image signal held by the holding capacitor cap is supplied to the gate electrode, and the common supply line when electrically connected to the common power supply line 43 through the thin film transistor 45 A pixel electrode 3 into which a drive current flows from the electric wire 43 and an organic functional layer 7 sandwiched between the pixel electrode 3 and the counter electrode 8 are provided. The organic functional layer 7 includes a light emitting layer, and the organic EL element 9 which is a light emitting element includes the pixel electrode 3, the counter electrode 8, the organic functional layer 7, and the like.

  In the pixel area A, when the scanning line 41 is driven and the first thin film transistor 44 is turned on, the potential of the signal line 42 at that time is held in the holding capacitor cap, and the second capacitance is changed according to the state of the holding capacitor cap. The conductive state of the thin film transistor 45 is determined. In addition, a current flows from the common power supply line 43 to the pixel electrode 3 through the channel of the second thin film transistor 45, and further a current flows to the counter electrode 8 through the organic functional layer 7. And according to the electric current amount at this time, the organic functional layer 7 light-emits.

  In the organic EL display device 200, light emitted from the organic functional layer 7 to the base 2 side is transmitted through the circuit element unit 30 and the base 2 and emitted to the lower side (observer side) of the base 2. Light emitted from the functional layer 7 to the opposite side of the substrate 2 is reflected by the counter electrode 8, and the light passes through the circuit element unit 30 and the substrate 2 and is emitted to the lower side (observer side) of the substrate 2. (Bottom emission type). Note that light emitted from the counter electrode can be emitted by using a transparent material as the counter electrode 8 (top emission type). In this case, ITO, Pt, Ir, Ni, or Pd can be used as the transparent material for the counter electrode.

  In this organic EL display device 200, the organic EL element 9 formed in the pixel region A has the structure of the light emitting element of the present invention described above. Therefore, an organic EL display device with high emission luminance and capable of bright display is obtained.

It is a schematic structure figure showing one embodiment of an organic EL device. It is explanatory drawing of the manufacturing method of the same organic EL device. 1 is a schematic configuration diagram of an image forming apparatus that is a first embodiment of an electronic apparatus. It is a schematic block diagram of the organic electroluminescence display which is 2nd Embodiment of an electronic device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Base | substrate, 3 ... 1st electrode, 4 ... Hole injection layer, 4a ... 1st liquid material, 4b ... 2nd liquid material, 5 ... Light emitting layer, 7 ... Functional layer, 8 ... 2nd electrode, 100 ... Image Forming device (electronic device), 200 ... organic EL display device (electronic device), EL1 ... organic EL device

Claims (11)

A functional layer comprising two or more layers including a hole injection layer and a light emitting layer;
A pair of electrodes sandwiching the functional layer,
The hole injection layer comprises a monomer having an epoxy group-containing monomer or oligomer and a thermally crosslinkable functional group that causes a polymerization reaction with the epoxy group on a substrate on which one of the electrodes is formed. Alternatively, an organic electroluminescence device is formed by arranging a second precursor that is an oligomer and polymerizing the first precursor and the second precursor on the substrate.   2. The organic electroluminescence device according to claim 1, wherein the second precursor is a monomer or an oligomer including an amino group, a hydroxyl group, or both as the thermally crosslinkable functional group.   3. The organic electroluminescence according to claim 1, wherein either the first precursor or the second precursor includes any of a triphenylamine derivative, a carbazole derivative, a pyrrole derivative, or a thiophene derivative. apparatus. Either the said 1st precursor or the said 2nd precursor contains either of following formula (1)-(11), The organic electroluminescent apparatus of Claim 3 characterized by the above-mentioned.

  In the said Formula (2)-(11), the integer n showing the number of the unit of a monomer or an oligomer is 1-20, The organic electroluminescent apparatus of Claim 4 characterized by the above-mentioned. In the formula (2) to (11), the functional group _R, R 1, _{R 2,} or _{R 3} is an organic electroluminescent device according to claim 4 or 5, characterized in that an alkyl group. Formula (4), (5), (8) - (11), the functional group _{Q 1} is N-T1, claim 4, wherein said T1 is an alkyl group The organic electroluminescence device according to the item. Formula (5), (9), (11), the functional group _{Q 2} are N-T2, the T2 is defined in any one of claims 4-6, characterized in that the alkyl group Organic electroluminescence device. A method for producing an organic electroluminescent device comprising a functional layer comprising two or more layers including a hole injection layer and a light emitting layer, and a pair of electrodes sandwiching the functional layer,
The step of forming the hole injection layer includes a first precursor that is a monomer or oligomer having an epoxy group on a substrate on which one of the electrodes is formed, and a thermally crosslinkable functional group that causes a polymerization reaction with the epoxy group. A step of disposing a second precursor which is a monomer or oligomer having a group by a droplet discharge method, and polymerizing the first precursor and the second precursor on the substrate. A method for manufacturing an electroluminescence device.   The method for producing an organic electroluminescence device according to claim 9, wherein the first precursor and the second precursor disposed on the substrate are polymerized by heating.   An electron comprising the organic electroluminescence device according to any one of claims 1 to 8 or the organic electroluminescence device produced by the method for producing an organic electroluminescence device according to claim 9 or 10. machine.

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