JP2010010333A - Organic el device and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL device suppressing reduction of luminance, and to provide a method of manufacturing the same. <P>SOLUTION: The organic EL device includes a first electrode layer 13, a charge injection metal layer 15 of an alkali metal compound or an alkali earth metal compound formed on the first electrode layer 13, a diffusion preventing layer 17 formed on the charge injection metal layer 15 and having a ligand combined with the alkali metal or the alkali earth metal into an organic metal complex, an organic light emitting layer 19 formed on the diffusion preventing layer 17, and a second electrode layer 22 formed on the organic light emitting layer 19. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic EL element and a method for manufacturing the same.

  The organic EL element includes a first electrode layer formed on the element substrate, an organic EL layer formed on the first electrode layer, and a second electrode layer formed on the organic EL layer. Yes. The organic EL layer is generally composed of a plurality of layers such as a charge injection layer or an organic light emitting layer made of an organic material.

  The organic light emitting layer applies voltage to the first electrode layer and the second electrode layer, injects holes and electrons from the first electrode layer and the second electrode layer into the organic light emitting layer, and in the organic light emitting layer, As electrons recombine, part of the released energy excites the light emitting molecules in the organic light emitting layer. As a result, the organic light emitting layer emits energy by emitting energy when the excited light emitting molecules return to the ground state.

  In addition, it is known that the concentration of the charge injecting material constituting the charge injection layer decreases as the light emission time increases. By reducing the concentration of the charge injecting material in the charge injection layer, the efficiency of charge injection into the organic light emitting layer is reduced, and the luminance of the organic light emitting layer is reduced.

Therefore, in order to suppress a decrease in charge injection efficiency with respect to the organic light emitting layer, a technique has been proposed in which a diffusion layer made of an electron injecting material is provided between the organic light emitting layer and the electron injection layer (see Patent Document 1 below). ). The diffusion layer is the same material as the electron injection layer.
JP 2003-272868 A

  However, in the technique described in Patent Document 1 described above, as the light emission time becomes longer, the electron injecting material constituting the electron injection layer and the diffusion layer diffuses into the organic light emitting layer, and the organic light emitting layer deteriorates. There is a risk of doing. There is a problem that the luminance is lowered due to the deterioration of the organic light emitting layer.

  This invention is made | formed in view of the subject mentioned above, Comprising: It aims at providing the organic EL element which can suppress the fall of a brightness | luminance, and its manufacturing method.

  In order to solve the above problems, an organic EL device of the present invention includes a first electrode layer, a charge injection metal layer made of an alkali metal compound or an alkaline earth metal compound formed on the first electrode layer, A diffusion preventing layer formed on the charge injecting metal layer and having a ligand which is combined with an alkali metal or an alkaline earth metal to form an organometallic complex; an organic light emitting layer formed on the diffusion preventing layer; And a second electrode layer formed on the organic light emitting layer.

  The method for producing an organic EL device of the present invention includes a step of forming a charge injection metal layer made of an alkali metal compound or an alkaline earth metal compound on the first electrode layer, and a charge injection material on the charge injection metal layer. Then, heat is applied to the charge injection material to form a charge injection layer, and an alkali metal or alkaline earth metal diffusing from the charge injection metal layer is captured on the charge injection layer. A step of forming a diffusion preventing layer, a step of forming an organic light emitting layer on the diffusion preventing layer, and a step of forming a second electrode layer on the organic light emitting layer.

  The method for producing an organic EL device of the present invention is characterized in that the charge injection material is heated and melted, and then fixed on the charge injection metal layer to form the charge injection layer.

  Further, in the method for manufacturing an organic EL element of the present invention, the diffusion preventing layer transfers heat from the charge injection material to the charge injection metal layer, and is removed from the charge injection metal layer due to the heat. It is characterized by capturing alkali metal or alkaline earth metal to be released.

  Further, in the method for producing an organic EL element of the present invention, a recess is formed in the charge injection metal layer, and the charge injection material is applied to the recess by applying heat to the charge injection material to melt it. The charge injection layer is formed by filling.

  The method for producing an organic EL device of the present invention is characterized in that the charge injection metal layer is made of lithium fluoride and the atoms detached from the charge injection metal layer are lithium.

  ADVANTAGE OF THE INVENTION According to this invention, the organic EL element which can suppress the fall of a brightness | luminance, and its manufacturing method can be provided.

  The present invention will be described below with reference to the drawings. FIG. 1 is a plan view of an organic EL display including an organic EL element according to an embodiment of the present invention. FIG. 2 is a plan view of pixels of the organic EL display. FIG. 3 is an enlarged cross-sectional view of the pixel.

  As shown in FIG. 1, the organic EL display 1 is used for home appliances such as a television, electronic equipment such as a mobile phone or a computer device, and includes an element substrate 2 and a plurality of pixels formed on the element substrate 2. 3 and a driving IC 4 that controls the light emission of the pixel 3.

  The element substrate 2 is made of, for example, glass or plastic, and a plurality of pixels 3 arranged in a matrix are formed in the display region D1 located in the center of the element substrate 2. A driving IC 4 is mounted on the non-display area D2 located at the end of the element substrate 2.

  As shown in FIG. 2, the light emitting region R is formed in the pixel 3, and the organic EL element 5 capable of emitting light is provided in the light emitting region R.

  Each pixel 3 is partitioned by a partition wall 6. The partition wall 6 is shaped so that the lower section is wider than the upper section, is formed on an insulator 7 to be described later, and is disposed so as to surround the pixel 3. The partition 6 is made of, for example, an inorganic insulating material such as silicon oxide, silicon nitride, or silicon oxynitride, or an organic insulating material such as phenol resin, novolac resin, acrylic resin, or polyimide resin.

  The pixel 3 can emit any one of red, green, and blue colors. This can determine the color of light emission by selecting the material which comprises the organic EL element 5 so that it may mention later. In the present embodiment, the pixel emits one of red, green, and blue. However, for example, the pixel may emit white or orange.

  In addition, a sealing substrate 8 is formed on the element substrate 2 so as to face the element substrate 2. The sealing substrate 8 is made of a transparent substrate, and for example, glass or plastic can be used. In this embodiment, since the top emission type organic EL display emits light from the element substrate 2 side toward the sealing substrate 8 side, a transparent member is used for the sealing substrate 8.

  In the display region D1 of the element substrate 2, a sealing material 9 is formed so as to cover the display region D1, and each pixel 3 is sealed by the element substrate 2, the sealing substrate 8, and the sealing material 9. By sealing each pixel 3, it is possible to reduce the ingress of oxygen or moisture into each pixel 3 and to suppress the deterioration of each pixel 3. Moreover, the sealing material 9 has a function as an adhesive and can fix the element substrate 2 and the sealing substrate 8 by being cured. As the sealing material 9, for example, a photocurable resin such as an acrylic resin, an epoxy resin, a urethane resin, or a silicon resin, or a thermosetting resin can be used. In this embodiment, a photocurable epoxy resin that is cured by irradiation with ultraviolet rays is used.

  Next, as shown in FIG. 3, various layers formed between the element substrate 2 and the sealing substrate 8 will be described. On the element substrate 2, a circuit layer 10 made of TFT, electric wiring or the like is formed. Further, an insulating layer 11 made of, for example, silicon nitride, silicon oxide, silicon oxynitride, or the like is formed on the circuit layer 10 so as not to cause an electrical short except for a predetermined region of the circuit layer 10.

  Further, a planarizing film 12 is formed on the insulating layer 11 in order to reduce surface irregularities caused by the circuit layer 10 and the insulating layer 11. Since the circuit layer 10 has a plurality of patterned electric wirings, irregularities are formed on the surface thereof. When the organic EL element 5 is formed on an uneven surface, the electrode layers constituting the organic EL element 5 may be short-circuited and the organic EL element 5 may not emit light. Therefore, the planarizing film 12 is formed on the circuit layer 10 and the insulating layer 11.

  For example, the planarizing film 12 may be made of an insulating organic material such as a novolac resin, an acrylic resin, an epoxy resin, or a silicon resin. The thickness of the planarizing film 12 is set to 2 μm or more and 5 μm or less, for example.

  Further, a contact hole S penetrating the planarizing film 12 is formed in the planarizing film 12. The contact hole S is formed so that the lower part is narrower than the upper part. The contact hole S is formed in each pixel 3, and a part of the circuit layer 10 is exposed at the bottom of the contact hole S.

  In addition, an insulator 7 is formed on the first electrode layer 13 so as to surround the light emitting region R. And the insulator 7 has prevented that the 1st electrode layer 13 and the 2nd electrode layer 22 mentioned later short-circuit. The insulator 7 is made of, for example, an organic insulating material such as phenol resin, acrylic resin, or polyimide resin, or an inorganic insulating material such as silicon nitride, silicon oxide, or silicon oxynitride.

  Further, between the first electrode layer 13 and the second electrode layer 22, an organic EL layer 14 in which a plurality of layers are stacked is provided. That is, as will be described later, the organic EL layer 14 includes an electron injection metal layer 15, an electron injection layer 16, a diffusion prevention layer 17, an electron transport layer 18, an organic light emitting layer 19, and a hole transport layer 20. And a hole injection layer 21.

  FIG. 4 is a cross-sectional view for explaining the configuration of the organic EL element 5. On the planarizing film 12 located in the light emitting region R, the organic EL element 5 is formed.

  As shown in FIG. 4, the organic EL element 5 includes a first electrode layer 13, an electron injection metal layer 15 made of an alkali metal compound or an alkaline earth metal compound formed on the first electrode layer 13, and an electron injection. An electron injection layer 16 as a charge injection layer formed on the metal layer 15, a diffusion prevention layer 17 formed on the electron injection layer 16, an electron transport layer 18 formed on the diffusion prevention layer 17, and an electron Organic light emitting layer 19 formed on transport layer 18, hole transport layer 20 formed on organic light emitting layer 19, hole injection layer 21 and hole injection layer formed on hole transport layer 20 And a second electrode layer 22 formed on the substrate 21.

  The first electrode layer 13 is formed from the inner peripheral surface of the contact hole S to the upper surface of the planarization film 12 and is connected to a part of the circuit layer 10 located in the contact hole S. The first electrode layer 13 is formed for each pixel 3 and is provided apart from the first electrode layer in the adjacent pixel. The 1st electrode layer 13 consists of materials, such as metals, such as aluminum, silver, copper, or gold, or these alloys, for example. The thickness of the first electrode layer 13 is set to, for example, 50 nm or more and 500 nm or less.

  The electron injection metal layer 15 is formed so as to cover the first electrode layer 13 in the light emitting region R. The electron injection metal layer 15 is made of an electron injection material that facilitates injection of electrons from the first electrode layer 13 toward the organic light emitting layer 19. For example, an alkali metal compound such as lithium fluoride or cesium fluoride, or magnesium fluoride is used. Alternatively, it consists of an alkaline earth metal compound such as calcium fluoride. The thickness of the electron injection metal layer 15 is set to, for example, not less than 0.1 nm and not more than 10 nm. In addition, since the electron injection metal layer 15 is formed on the first electrode layer 13 using a vapor deposition method, the electron injection metal layer 15 has a large number of recesses. The size of the recess is, for example, 10 nm or less.

  The electron injection layer 16 is formed so as to cover the electron injection metal layer 15. The electron injection layer 16 is formed on the electron injection metal layer 15 using a vapor deposition method, and then heat is applied to the electron injection layer 16 to melt the electron injection layer 16 and fix it to the electron injection metal layer 15. Is. Therefore, a part of the electron injection layer 16 is filled in the concave portion of the electron injection metal layer 15, the contact area between the electron injection metal layer 15 and the electron injection layer 16 can be increased, and electrons from the electron injection metal layer 15 can be increased. Can be improved. Such an electron injection layer 16 is, for example, 1,1-dimethyl-2,5-di (2-pyridyl) silole (PySPy) or 2,5-bis (6 ′-(2 ′, 2 ″ -bipyridyl) -1 , 1-dimethyl-3,4-diphenylsilole (PyPySPyPy) and other silole derivatives, 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole or 2, It consists of oxadiazole derivatives such as 5-bis (1-naphthyl) -1,3,4-oxadiazole etc. The thickness of the electron injection layer 16 is set to, for example, 1 nm or more and 50 nm or less.

  Further, when foreign matter such as particles is present on the electron-injecting metal layer 15 by melting the electron-injecting layer 16, a part of the melted electron-injecting layer 16 covers the periphery of the foreign matter, so that the organic EL due to the foreign matter is covered. It is possible to reduce irregularities or defects in the layer constituting the layer 14 and suppress a short circuit between the electrodes or a leakage current between the electrodes. Further, by covering the periphery of the foreign matter, the gap around the foreign matter can be reduced, and oxygen or moisture can be prevented from entering the organic EL element through the gap.

  The diffusion prevention layer 17 is formed so as to cover the electron injection layer 16. The diffusion preventing layer 17 has a ligand that is combined with an alkali metal or an alkaline earth metal to form an organometallic complex. As the organometallic complex, the central metal is, for example, lithium, cesium, magnesium or calcium, and for example, 8-quinolinolatolithium, cesium acetylacetonate, bis (8-quinolinolato) magnesium, calcium acetylacetonate or the like. The thickness of the diffusion preventing layer 17 is set to, for example, 1 nm or more and 10 nm or less.

  As the light emission time becomes longer, the alkali metal or alkaline earth metal constituting the electron injection metal layer 15 diffuses from the electron injection metal layer 15 toward the organic light emission layer 19, and the electron injection property is reduced. There is a possibility that impurities are mixed in 19 and the light emission efficiency of the organic light emitting layer 19 is lowered. When a voltage is applied to the organic EL layer 14, electrons move in the diffusion preventing layer 17, but there are excess electrons that do not contribute to light emission in the diffusion preventing layer 17. By interaction with the central metal of the organic metal complex that constitutes, the organic metal complex that constitutes the diffusion preventing layer 17 includes molecules in which the central metal is dissociated. Further, although the diffusion preventing layer 17 is formed in a vacuum environment or in a nitrogen atmosphere, oxygen or moisture is taken in during the film formation, and these impurities and oxygen or moisture present in the organic material from the beginning. As a result of the interaction between the impurities such as the central metal of the organometallic complex that constitutes the diffusion preventing layer 17, molecules in which the central metal is separated exist in the organometallic complex that constitutes the diffusion preventing layer 17. That is, in the diffusion preventing layer 17, there are many ligand-only molecules. Then, by forming the diffusion preventing layer 17 between the electron injection metal layer 15 and the organic light emitting layer 19, the alkali metal or alkaline earth metal constituting the electron injection metal layer 15 is directed toward the organic light emitting layer 19. It is possible to suppress the movement of the ligand-only molecules into the organic light emitting layer 19 by capturing the moving alkali metal or alkaline earth metal. As a result, it can suppress that the luminous efficiency of the organic light emitting layer 19 falls.

  Further, if there is a concentration gradient, the substance tends to move from a high concentration to a low concentration. Therefore, a diffusion prevention layer 17 is provided on the electron injection metal layer 15 made of an alkali metal compound or an alkaline earth metal compound, and the concentrations of alkali metal and alkaline earth metal are directed from the electron injection metal layer 15 toward the organic light emitting layer 19. The gradient can be reduced. As a result, it is possible to suppress the movement of the alkali metal or alkaline earth metal from the electron injection metal layer 15 toward the organic light emitting layer 19.

The electron transport layer 18 is formed so as to cover the diffusion prevention layer 17. The electron transport layer 18 is made of a material that facilitates transport of electrons from the first electrode layer 13 toward the organic light emitting layer 19. For example, tris (8-quinolinolato) aluminum (Alq ₃ ), bis (2-methyl-8) is used. -Quinolinolato) -4- (phenylphenolato) aluminum-based metal complexes such as aluminum, silole derivatives such as PySPy and PyPySPyPy, 9,10-di (2 ', 2 "-bipyridyl) anthracene, 2,5-di (2 ', 2 "-bipyridyl) thiophene, 2,5-di (3', 2" -bipyridyl) thiophene, 6'6 "-di (2-pyridyl) 2,2 ': 4', 3": 2 ", Pyridine derivatives such as 2 ′ ″-quaterpyridine, 4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 0-di (1,10-phenanthroline-2-yl) anthracene, 2,6-di (1,10-phenanthroline-5-yl) pyridine, 1,3,5-tri (1,10-phenanthroline-5- Yl) phenanthroline derivatives such as benzene, 9,9'-difluoro-bis (1,10-phenanthroline-5-yl), diphenylquinone derivatives, perylene derivatives, oxadiazole derivatives, thiophene derivatives, triazole derivatives, thiadiazole derivatives, oxins Metal complexes of derivatives, quinoxaline derivatives, polymers of quinoxaline derivatives, benzazole compounds, gallium complexes, pyrazole derivatives, perfluorinated phenylene derivatives, triazine derivatives, pyrazine derivatives, benzoquinoline derivatives, imidazopyridine derivatives, borane derivatives, polyamines Ruarukan or butadiene derivative and the like can be used. The thickness of the electron transport layer 18 is set to, for example, 20 nm or more and 60 nm or less.

The organic light emitting layer 19 is formed so as to cover the electron transport layer 18. When the organic light emitting layer 19 emits red light, for example, bis (2-methyl-8-quinolinolato) -4- (phenylphenolato) aluminum, 1,4-phenylenebis (triphenylsilane), 1,3 - bis (triphenylsilyl) benzene, 1,3,5-tri (9H-carbazol-9-yl) benzene, CBP, Alq ₃ or the host material bis [2- (2-benzothiazyl such SDPVBi benzoyl -kN3 ) Phenyl-kC] (2,4-pentadionato-kO, kO) Iridium and other organic iridium compounds, organic platinum compounds, DCJTB, coumarin, quinacridone, perinone derivatives having a phenanthrene group, oligothiophene derivatives or perylene derivatives Can be used.

When green light is emitted, for example, bis (2-methyl-8-quinolinolato) -4- (phenylphenolato) aluminum, 1,4-phenylenebis (triphenylsilane), 1,3-bis (tri Phenylsilyl) benzene, 1,3,5-tri (9H-carbazol-9-yl) benzene, host materials such as CBP, Alq ₃ or SDPVBi, or bis [pyridinyl-kN-phenyl-kC] to these host materials (2,4-pentadionato-kO, kO) iridium, bis [2- (2-benzoxazolyl) phenolato] zinc (II), styrylamine, perlin, silole derivatives having a benzene ring, perinone derivatives having a phenanthrene group , Dopant materials such as oligothiophene derivatives, perylene derivatives or azomethine zinc complexes A material containing a material can be used.

  In the case of emitting blue light, for example, a host material such as CBP or SDPVBi, or these host materials include tetra (2-methyl-8-hydroxyquinolinato) boron lithium, styrylamine, perlin, cyclopentadiene derivatives, tetra A compound containing a dopant material such as phenylbutadiene, a compound in which a triphenylamine structure and a vinyl group are bonded, an oxadiazole derivative, a pyrazoloquinoline derivative, a distyrylarylene derivative, or a silole derivative having a benzene ring can be used. . In addition, the thickness of the organic light emitting layer 19 is set to 20 nm or more and 40 nm or less, for example.

  The hole transport layer 20 is formed so as to cover the organic light emitting layer 19. The hole transport layer 20 has a function of transporting the charge injected from the second electrode layer 22 toward the organic light emitting layer 19. The hole transport layer 20 is formed of, for example, N, N′-bis (3-methylphenyl)-(1,1′-biphenyl) -4,4′-diamine (TPD), 4,4′-bis [N— Aromatic diamine compounds such as (1-naphthyl) -N-phenyl-amino] biphenyl (α-NPD) or 4,4 ′, 4 ″ -tris (N- (3-methylphenyl) N-phenylamino) tri A starburst aromatic compound or aromatic amine compound such as phenylamine (m-MTDATA), or a mixture or laminated film thereof can be used.

  In addition, the hole transport layer 20 is formed on the organic light emitting layer 19 with a heterocyclic compound layer such as 1,4,5,8,9,12-hexaazatriphenylene or a derivative having a cyano group or the like bonded thereto. A stacked film in which layers of 4,4′-bis [N- (1-naphthyl) -N-phenyl-amino] biphenyl (α-NPD) and the like are stacked can be used. Note that the thickness of the hole transport layer 20 is set to, for example, 10 nm or more and 50 nm or less.

  The hole injection layer 21 is formed so as to cover the hole transport layer 20. The hole injection layer 21 is made of a hole injection material that facilitates injection of holes from the second electrode layer 22 toward the organic light emitting layer 19, and is made of, for example, copper phthalocyanine (CuPc), titanium oxide, nickel oxide, or the like. . The thickness of the hole injection layer 21 is set to, for example, 10 nm or more and 50 nm or less.

  The second electrode layer 22 is formed from the hole injection layer 21 to the insulator 7. Further, the second electrode layer 22 is formed so as to cover the display region D1, and the second electrode layer 22 functions as a common electrode between adjacent pixels. Since the second electrode layer 22 is a common electrode, it is not necessary to separately form a contact hole for connecting the circuit layer 10 connected to the drive circuit of each pixel and the second electrode layer 22. The aperture ratio, which is the ratio of the total area of the pixels occupying D1, is improved, the current density of the pixels is reduced, and the organic EL element can have a long lifetime. In addition, an insulating structure whose upper part is wider than the lower part for electrically separating and forming the second electrode layer 22 is not necessary. If an insulating structure having an upper portion wider than the lower portion is formed on the insulator 7, the second electrode layer is separated for each pixel by the insulating structure. It is not covered with the electrode layer. Therefore, moisture or the like easily enters the organic EL element through the side surface of the insulating structure not covered with the second electrode layer, and the device is easily deteriorated. On the other hand, in the present embodiment, since the second electrode layer 22 covers the entire surface of the display region D1, there is an effect that deterioration of the device can be avoided.

  The second electrode layer 22 is made of a material that can transmit light emitted from the organic light emitting layer 19, and uses a light-transmitting conductive material such as indium tin oxide (ITO) or tin oxide. Formed. The second electrode layer 22 can be made of, for example, a material such as magnesium, silver, aluminum, or calcium, or an alloy thereof. The thickness of the second electrode layer 22 is set to 30 nm or less to form a light transmissive electrode. Can do. As a result, the light emitted from the organic light emitting layer 19 passes through the second electrode layer 22 and is emitted from the organic EL element 5 to the outside.

  A protective layer 23 is formed on the organic EL element 5 so as to cover the organic EL element 5. The protective layer 23 seals the organic EL element 5 and protects the organic EL element from moisture or outside air, and has a light-transmitting function, such as silicon nitride, silicon oxide, or silicon nitride carbide. Made of inorganic material. The thickness of the protective layer 23 is set to, for example, 100 nm or more and 5 μm or less. The sealing material 9 is formed in the display region D1 so as to cover the protective layer 23.

  As described above, according to the organic EL element according to the present embodiment, the electron injection metal layer 15 capable of improving the electron injection efficiency is formed on the first electrode layer 13, and the electron injection metal layer 15 and the organic By forming the diffusion preventing layer 17 between the light emitting layer 19, it is possible to suppress the diffusion of the components constituting the electron injecting metal layer 15 and to suppress the luminance of the organic light emitting layer 19 from decreasing.

  Below, the manufacturing method of the organic electroluminescent display 1 containing the organic electroluminescent element 5 which concerns on embodiment of this invention is demonstrated in detail using FIGS. 5 to 8 are cross-sectional views of one pixel.

  As shown in FIG. 5A, an element substrate 2 in which a circuit layer 10, an insulating layer 11, and a planarizing film 12 are stacked on the upper surface is prepared. The circuit layer 10 and the insulating layer 11 are formed in a predetermined pattern by using a conventionally known thin film forming technique such as a CVD method, a vapor deposition method or a sputtering method, or a thin film processing technique such as an etching method or a photolithography method. Further, the planarizing film 12 is formed on the insulating layer 11 by using, for example, a conventionally known spin coating method.

  Next, the planarizing film 12 is exposed on the planarizing film 12 using an exposure mask, and further developed and baked to expose a part of the circuit layer 10 as shown in FIG. Then, a contact hole S whose lower part is narrower than the upper part is formed in the planarizing film 12. Further, a metal film made of, for example, aluminum is formed on the planarizing film 12 in which the contact holes S are formed. Then, as shown in FIG. 6A, the metal film is patterned to form the first electrode layer 13.

  Next, an organic insulating material layer made of, for example, an acrylic resin is formed on the first electrode layer 13 and the partially exposed planarizing film 12 by using, for example, a spin coating method. Then, the organic insulating material layer is patterned using a photolithography method with respect to the organic insulating material layer to form the insulator 7 as shown in FIG. The insulator 7 is formed so as to surround the light emitting region R, and a part of the upper surface of the first electrode layer 13 is exposed.

  Next, as shown in FIG. 7A, a partition wall 6 having a width lower than the upper portion is formed on the insulator 7 by using a well-known photolithography method. The partition wall 6 is formed so as to surround each pixel 3. The partition wall 6 has a function as a support table on which a deposition mask can be placed. The partition wall 6 is provided so that the substrate and the vapor deposition mask are in contact with each other and the substrate is not damaged when the vapor deposition mask is opposed to the substrate. Further, the partition wall 6 is made wider at the lower part than at the upper part, whereby the strength of the lower part of the partition wall 6 can be increased, and the partition wall 6 can be prevented from being damaged when a deposition mask is placed. it can.

  Then, as shown in FIG. 7B, an organic EL layer 14 is formed on the first electrode layer 13 in the light emitting region R by using a vapor deposition method. Specifically, first, an electron injection metal layer 15 made of lithium fluoride as an alkali metal compound is formed on the first electrode layer 13 by vapor deposition. Then, an organic material layer made of PyPySPyPy is formed on the electron injection metal layer 15. Further, the electron injection material constituting the organic material layer is heated to melt the organic material layer, so that the electron injection material is filled in the recesses of the electron injection metal layer 15 to form the electron injection layer 16. The temperature of the heat applied to the organic material layer is set to be 90 ° C. or higher and 130 ° C. or lower, for example, from the glass transition point of the electron injection material constituting the organic material layer to below the melting point.

  Further, a diffusion prevention layer 17 made of 8-quinolinolato lithium is formed on the electron injection layer 16. When the electron injection material is melted by applying heat to form the electron injection layer 16, alkali metal may be detached from the electron injection metal layer 15 due to the heat transmitted to the electron injection metal layer 15. Since the diffusion preventing layer 17 contains molecules of only the ligands with the central metal separated, the alkali metal can be captured. As a result, it is possible to suppress the diffusion of the alkali metal desorbed from the electron injection metal layer 15 on the diffusion preventing layer 17.

An electron transport layer 18 made of Alq ₃ is formed on the diffusion prevention layer 17. Then, an organic light emitting layer 19 made of CBP is formed on the electron transport layer 18. Since the diffusion prevention layer 17 is formed between the first electrode layer 13 and the organic light emitting layer 19, alkali metal diffuses into the organic light emitting layer 19 from the electron injection metal layer 15 toward the organic light emitting layer 19, Deterioration of the organic light emitting layer 19 can be suppressed. Further, a hole transport layer 20 made of α-NPD and a hole injection layer 21 made of CuPc are formed on the organic light emitting layer 19. In this way, the organic EL layer 14 can be formed on the first electrode layer 13.

  Next, as shown in FIG. 8A, for example, 10% by mass of magnesium and 90% by mass of silver are formed on the organic EL layer 14 and the insulator 7 so as to cover the display region D1 by using a conventionally known vapor deposition method. The second electrode layer 22 having a thickness of 20 nm and made of a mixture of the second electrode layer and the second electrode layer is formed. The second electrode layer 22 is common to adjacent pixels and functions as a common electrode. By using the second electrode layer 22 as a common electrode, the second electrode layer 22 can be formed without using a vapor deposition mask having fine pores, so that the manufacturing process can be simplified. In this way, the organic EL element 5 can be formed.

  Further, as shown in FIG. 8B, for example, a thickness of silicon nitride is used so that the organic EL element 5 is not deteriorated on the entire surface of the display region D1 by using, for example, a chemical vapor deposition method (thermal CVD method). A protective layer 23 having a thickness of 1.5 μm is formed.

  Then, the sealing substrate 8 is disposed opposite to the element substrate 2 on which the organic EL element 5 is formed, and both are bonded via a sealing material 9. Specifically, the sealing material 9 is previously applied to the sealing substrate 8 by using, for example, a screen printing method. Then, the sealing substrate 8 is fixed to the element substrate 2 via the sealing material 9. The operation of fixing the sealing substrate 8 to the element substrate 2 with the sealing material 9 is performed in an inert gas such as nitrogen gas or argon gas or in a high vacuum, for example, so that the element substrate 2 and the sealing substrate are fixed. It is possible to suppress oxygen and moisture from being contained between the two. Then, the organic EL display 1 can be manufactured by mounting the driving IC 4 in the non-display area D2.

  As described above, according to the embodiment of the present invention, the alkali metal desorbed from the electron injection metal layer 15 can be captured by the diffusion prevention layer 17, and the alkali metal diffuses into the organic light emitting layer 19. Can be suppressed, and a reduction in the luminance of the organic light emitting layer 19 can be effectively prevented.

  Further, when the electron injection material is heated and melted to form the electron injection layer 16, heat is conducted to the electron injection metal layer 15, and alkali metal may be detached from the electron injection metal layer 15. Before the light emitting layer 19 is formed, the diffusion preventing layer 17 is formed between the first electrode layer 13 and the organic light emitting layer 19, so that the alkali metal diffusing from the electron injecting metal layer 15 is diffused in the diffusion preventing layer 17. It is possible to suppress trapping and intrusion into the organic light emitting layer 19.

  Further, since the electron injection layer 16 previously melted on the electron injection metal layer 15 is formed in a state before the organic light emitting layer 19 is formed, the organic light emitting layer 19 is heated by heat at the time of melting the organic material layer. The organic EL display having a long life can be produced without deterioration. Thus, according to the present embodiment, it is possible to provide a method for manufacturing an organic EL element capable of suppressing a decrease in luminance.

  In addition, this invention is not limited to the above-mentioned form, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention. In the above-described embodiment, the top emission organic EL element has been described. However, a bottom emission organic EL element may be used as long as the effects of the present invention are achieved.

It is a top view of the organic electroluminescent display containing the organic electroluminescent element which concerns on embodiment of this invention. It is a top view of the pixel arranged in the matrix form. It is an expanded sectional view of the pixel containing the organic EL element which concerns on embodiment of this invention. It is sectional drawing of the organic EL element which showed each layer which comprises an organic EL element. FIG. 5A and FIG. 5B are cross-sectional views of a pixel for explaining a manufacturing process of an organic display including an organic EL element according to an embodiment of the present invention. 6A and 6B are cross-sectional views of a pixel for explaining a manufacturing process of an organic display including an organic EL element according to an embodiment of the present invention. FIGS. 7A and 7B are cross-sectional views of a pixel for explaining a manufacturing process of an organic display including an organic EL element according to an embodiment of the present invention. 8A and 8B are cross-sectional views of a pixel for explaining a manufacturing process of an organic display including an organic EL element according to an embodiment of the present invention.

Explanation of symbols

1 Organic EL Display 2 Element Substrate 3 Pixel 4 Drive IC
DESCRIPTION OF SYMBOLS 5 Organic EL element 6 Partition 7 Insulator 8 Sealing substrate 9 Sealing material 10 Circuit layer 11 Insulating layer 12 Planarizing film 13 First electrode layer 14 Organic EL layer 15 Electron injection metal layer 16 Electron injection layer 17 Diffusion prevention layer 18 Electron Transport layer 19 Organic light emitting layer 20 Hole transport layer 21 Hole injection layer 22 Second electrode layer 23 Protective layer D1 Display region D2 Non-display region R Light emission region S Contact hole

Claims (6)

A first electrode layer;
A charge injection metal layer comprising an alkali metal compound or an alkaline earth metal compound formed on the first electrode layer;
A diffusion preventing layer formed on the charge injection metal layer and having a ligand that is combined with an alkali metal or an alkaline earth metal to form an organometallic complex;
An organic light emitting layer formed on the diffusion preventing layer;
An organic EL device comprising: a second electrode layer formed on the organic light emitting layer. Forming a charge injection metal layer comprising an alkali metal compound or an alkaline earth metal compound on the first electrode layer;
Depositing a charge injection material on the charge injection metal layer and then applying heat to the charge injection material to form a charge injection layer;
Forming a diffusion preventing layer for capturing an alkali metal or alkaline earth metal diffusing from the charge injection metal layer on the charge injection layer;
Forming an organic light emitting layer on the diffusion preventing layer;
And a step of forming a second electrode layer on the organic light emitting layer. In the manufacturing method of the organic EL element of Claim 2,
A method of manufacturing an organic EL element, wherein the charge injection material is melted by applying heat and then fixed on the charge injection metal layer to form the charge injection layer. In the manufacturing method of the organic EL element of Claim 3,
The diffusion prevention layer captures heat added to the charge injection material to the charge injection metal layer and captures alkali metal or alkaline earth metal that is desorbed from the charge injection metal layer due to the heat. The manufacturing method of the organic EL element characterized by these. In the manufacturing method of the organic EL element of Claim 2,
The charge injection metal layer has a recess,
A method for manufacturing an organic EL element, wherein the charge injection material is melted by applying heat to fill the recess with the charge injection material to form the charge injection layer. In the manufacturing method of the organic EL element of Claim 2,
The method of manufacturing an organic EL element, wherein the charge injection metal layer is made of lithium fluoride, and the atoms detached from the charge injection metal layer are lithium.

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