JP2005093402A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bright and high-stability light emitting device having an excellent light emission characteristic with low power consumption because a sufficient light emission characteristic can not be provided by a structure using a light emitting element having a structure composed by stacking a conventional organic material on an electrode formed of an inorganic material. <P>SOLUTION: This light emitting device is provided with an insulating or semi-insulating barrier layer in a thickness at a level allowing a tunnel current to be carried between a hole injection electrode and a hole injection area or a hole transportation area of an EL layer. The light emitting device is so structured that the hole injection electrode is equipped with an electrode layer formed of an oxide conductive material containing silicon or silicon oxide; and the insulating or semi-insulating barrier layer containing at least one kind selected from oxygen, nitrogen and carbon, and silicon is formed between the electrode layer and the hole injection area or the hole transportation area in the EL layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, a light-emitting element in which a medium containing electroluminescence (hereinafter also referred to as “EL”) or a mixture containing an organic substance and an inorganic substance, called electroluminescence, is interposed between electrodes is arranged in a predetermined form. The present invention relates to a light emitting device having the structure described above.

  A light-emitting element formed by interposing a substance that expresses EL between a pair of electrodes is known. This light-emitting element is particularly called an organic EL element because organic substances are mainly used as a substance that expresses EL. EL is expressed by emitting light when holes injected from one electrode and electrons injected from the other electrode recombine to excite the emission center and return to the ground state. It is said to do.

  The electrode on the side of injecting holes called an anode uses indium tin oxide (hereinafter also referred to as “ITO”) having a work function of about 5 eV, and an organic substance having a high hole transporting property is used. It was in contact. In addition, an electrode called the cathode, which is used for injecting electrons, is made of a material in which an alkali metal or alkaline earth metal such as Li or Mg having a low work function is contained in aluminum. An element was formed by forming a contact.

  In many cases, a layer structure is employed in order to efficiently express EL. For example, tris-8-quinolinolato is used as a hole transporting layer such as 4,4′-bis- [N- (naphthyl) -N-phenyl-amino] biphenyl (α-NPD), which is an aromatic amine material. Aluminum complex (aluminato-tris-8-hydroxyquinolate (Alq3)) is used for the light-emitting layer and the electron transport layer. ITO is used for the hole-injecting electrode, and magnesium is used for the electron-injecting electrode. Silver alloy was used (for example, refer nonpatent literature 1).

As one form of a display panel to which such a light emitting element is applied, EL is expressed as described above between an electrode (row electrode) extending in one direction and an electrode (column electrode) extending in a direction intersecting with the electrode (row electrode). A medium arranged in a matrix with a medium to be interposed is known (for example, see Patent Document 1).
C. W. C. T., et al., Journal of Applied Physics, Vol. 65, p. 3610, 1988 Japanese National Patent Publication No. 10-503605

  However, in a light emitting device having a structure in which a conventional organic material is laminated on an electrode formed of an inorganic material, sufficient light emission characteristics cannot be obtained. In addition, the power consumption is high, the half life of luminance is short, and there are problems to be improved regarding stability.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a light-emitting device having excellent light-emitting characteristics, low power consumption, brightness, and high stability.

  In the present invention, at least one electrode sandwiching an organic substance containing a substance that expresses EL or a medium containing an organic substance and an inorganic substance (hereinafter also referred to as an “EL layer”) is used as a first electrode layer made of a conductive material. And a second electrode layer made of an oxide conductive material containing silicon or silicon oxide, and a hole injecting electrode (hereinafter also referred to as “hole injecting electrode”). . In particular, a structure in which a hole injection region or a hole injection transport region is provided on the second electrode layer side in the EL layer is a preferable embodiment in the present invention.

  In the present invention, at least one of the electrodes of a pixel in which an EL layer is interposed between an electrode extending in one direction and an electrode extending in a direction intersecting with the electrode includes a second electrode layer that enhances hole injection properties The first electrode layer having a resistivity lower than that of the second electrode layer is provided, and the hole injection region or the hole injection transport region of the EL layer is provided adjacent to the second electrode layer. It is characterized by that.

  The present invention includes an insulating or semi-insulating barrier layer having a thickness that allows a tunnel current to flow between a hole injection electrode and a hole injection region or a hole transport region in an EL layer. This makes it possible to solve the above problems. That is, in the hole injection electrode, an electrode layer made of an oxide conductive material containing silicon or silicon oxide is provided, and oxygen, nitrogen or the like is interposed between the electrode layer and the hole injection region or the hole transport region in the EL layer. And an insulating or semi-insulating barrier layer containing at least one selected from carbon and silicon.

  Examples of the oxide conductive material forming the electrode layer provided on the side of the EL layer that is in contact with the hole injection region or the hole transport region include indium tin oxide, zinc oxide, and indium oxide. One kind selected from zinc oxide and zinc oxide to which gallium is added is preferable, and the ratio of silicon or silicon oxide is 1 to 15 atomic%, preferably 2 to 5 atomic%.

  In the combination of the second electrode layer and the first conductive layer, the first electrode layer is made of aluminum or a conductive material mainly containing aluminum, or a metal and the metal A conductive material containing nitrogen at a concentration equal to or lower than the stoichiometric composition ratio may be used.

  The EL layer in the present invention includes layers called a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer from the viewpoint of carrier transport characteristics. The distinction between a hole injection layer and a hole transport layer is not necessarily strict, and these are the same in the sense that hole transportability (hole mobility) is a particularly important characteristic. For convenience, the hole injection layer is a layer in contact with the anode, and the layer in contact with the hole injection layer is referred to as a hole transport layer to be distinguished. The same applies to the electron transport layer and the electron injection layer. The layer in contact with the cathode is called an electron injection layer, and the layer in contact with the electron injection layer is called an electron transport layer. The light emitting layer may also serve as an electron transport layer, and is also referred to as a light emitting electron transport layer.

  Of course, the layer structure for expressing EL can be changed, and instead of having a specific electron injection region or a light emitting region, it has an electrode for this purpose, or a light emitting material is dispersed. Such modifications can be allowed without departing from the spirit of the present invention.

  In addition, the EL layer applied in the present invention is not limited to an organic material, and may exhibit a similar function even when a material obtained by combining an organic material and an inorganic material, or a material obtained by adding a metal complex to an organic material is used. Can be applied.

  In the light emitting device configured as described above, since the hole injection electrode and the hole injection region are not in direct contact with each other, the effect of the original work function of the hole injection electrode is manifested. Injection efficiency is improved, and light emission characteristics can be improved.

  Hereinafter, embodiments of the present invention will be described. In addition, in the following description, in the equivalent site | part common between each drawing, it shall attach and show the same code | symbol, and it abbreviate | omits about the overlapping description.

  FIG. 1 is a plan view showing an embodiment of a light-emitting device of the present invention. A pixel portion 20 in which self-luminous pixels made of light-emitting elements are arranged in a matrix on a substrate 10 having an insulating surface, and an input terminal portion 18. , 19 are shown. The self-luminous pixel is formed at the intersection of the first electrode 11 extending in one direction and the second electrode 17 extending in the direction intersecting therewith, and an EL layer is provided between the pair of electrodes. . About this structure, the longitudinal cross-sectional structure along the AB line | wire shown in a figure is shown in FIG.

  As shown in FIG. 7, the self-luminous pixel 100 has a structure in which an EL layer 16 is interposed between the first electrode 11 and the second electrode 17, and adjacent elements are formed on the insulating layer 14. It is electrically separated by the partition wall 15. The insulating layer 14 acts to prevent the first electrode 11 and the second electrode 17 from being short-circuited at the end of the EL layer 16. FIG. 7 shows a structure in which the shape of the partition wall 15 is a so-called reverse taper shape in which the outer end of the top part protrudes outward with respect to the bottom part. However, as shown in FIG. A so-called forward-tapered partition wall 21 located inside may be formed. In the structure shown in FIG. 8, the adjacent separation structure of the self-luminous pixel 100 in which the first electrode 11, the EL layer 16, and the second electrode 17 are stacked on the substrate 10 is performed by the forward-tapered partition wall 21. Yes. In this structure, the EL layer 16 is formed along the inclination of the side surface of the partition wall 21, but the stress applied to the EL layer can be relaxed by setting the inclination angle of the partition wall 21 to 30 to 65 degrees.

  7 and 8 show a configuration in which the first electrode 11 formed first on the substrate 10 is a hole injection electrode. In the present invention, the hole injection electrode has a laminated structure of a first electrode layer, a second electrode layer, and at least two layers. Needless to say, the second electrode 17 may be a hole injection electrode and may have a laminated structure of at least two layers.

  The first electrode layer is made of indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), zinc oxide added with gallium (GZO) or other oxides to reduce the resistance of the hole injection electrode. A conductive material containing titanium, tantalum, molybdenum, chromium, aluminum, or a metal containing aluminum as a main component, or a conductive material containing nitrogen at a concentration equal to or lower than the stoichiometric composition ratio with the metal. By including nitrogen, the adhesion to the oxide conductive material formed thereon can be improved.

  The second electrode layer is made of indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), zinc oxide added with gallium (GZO), or the like for the purpose of improving the hole injection property. A material containing 1 to 10 atomic% of silicon oxide in the selected oxide conductive material is used.

  Typically, an oxide conductive material (hereinafter also referred to as “ITSO”) in which silicon oxide is contained in indium tin oxide (ITO) in an amount of 1 to 10 atomic%, preferably 2 to 5 atomic% is used. An insulating or semi-insulating barrier layer is formed on the surface in contact with the hole injection electrode and the EL layer so that the silicon oxide concentration is increased and the carrier can move between the two stacked layers. Is provided. That is, the thickness is such that a current flows by a tunnel current, and at least one selected from oxygen, nitrogen, and carbon and a silicon compound, or the silicon compound and an oxide conductive material are combined to form a base By providing a non-diode characteristic barrier layer having a composition different from that of the hole injection electrode, carriers can be moved and the hole injection electrode and the organic compound layer are physically separated.

The data shown in Table 1 shows the results of measuring the composition of ITSO and ITO by ESCA (Electron Spectroscopy for Analysis) that can specify the chemical bonding state of elements on the sample surface. The numerical values in the table indicate the result of the abundance ratio of each element expressed as a percentage. From the results in Table 1, the ITSO sample shows the result that the silicon concentration is high in the region of the outermost surface of 1 nm or less on the surface. In the case of ITO, of course, silicon is not detected. That is, the above-mentioned barrier layer can be easily formed by depositing silicon or silicon oxide on the surface.

  As another structure of the hole injection electrode, as the first electrode layer, indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), zinc oxide added with gallium (GZO), or the like is used. A material containing 0.1 to 10 atomic% of silicon oxide in the selected oxide conductive material can be used. In this case, it is desirable that the concentration of silicon oxide to be added is lower than that of the second conductive layer. That is, by adding silicon oxide to the above oxide conductive material, crystallization is inhibited and the smoothness of the electrode surface can be improved. On the other hand, since the resistivity is improved by including silicon oxide, it is preferable to reduce the concentration of the first conductive layer for the purpose of reducing electric resistance.

  The EL layer is formed by laminating an organic substance or a mixture of an organic substance and an inorganic substance called a hole transport layer, a light emitting layer, or an electron transport layer because of its carrier transport property. In addition, a hole injection layer may be provided between the hole injection electrode and the hole transport layer, or an electron injection layer may be provided between the electron injection electrode and the electron transport layer. The distinction between a hole injection layer and a hole transport layer, and an electron injection layer and an electron transport layer is not necessarily strict, and these are hole transportability (hole mobility) and electron transportability (electron mobility). Is the same in the sense that is a particularly important property. Alternatively, a hole blocking layer may be provided between the electron transport layer and the light emitting layer.

The light-emitting layer (EML) may have a structure in which a guest material such as a pigment or a metal complex is added to the host material to change the emission color. That is, the light emitting layer may be formed by including a fluorescent material or a phosphorescent material. For example, in order to perform color display using the three primary colors of red, green, and blue, a material for forming the light emitting layer is appropriately selected so that the light emission colors are different among the pixels. However, since the driving voltage, brightness, and light emission lifetime are different for each emission color, a pixel with a short emission lifetime may be formed using a phosphorescent material and driven at a low voltage. For example, in order to obtain green phosphorescence, 4,4′-N, N′-dicarbazole- is used as a host material with tris- (2-phenylpyridine) iridium (Ir (ppy) ₃ ), which is an Ir complex, as a guest material. A pixel including a light emitting layer using biphenyl (CBP) is formed. Further, red phosphorescence can be obtained by using a europylium complex (Eu (DBM) ₃ (Phen)) as a guest material.

  As the hole injection layer (HIL) in the EL layer, copper phthalocyanine (CuPc), 4,4′-bis- [N- (naphthyl) -N-phenyl-amino] biphenyl (α-), which is an aromatic amine material, is used. In addition to NPD) 4,4 ', 4 "-tris (N-3-methylphenyl-N-phenyl-amino) triphenylamine (MTDATA), poly (ethylenedioxythiophene) as a high molecular weight organic compound / Poly (styrenesulfonic acid) aqueous solution) PEDOT / PSS), etc. Further, molybdenum oxide or a mixture of molybdenum oxide and the above-described hole injection material may be used as an inorganic substance. The electron transport layer (ETL) can be formed using Alq3, 1,2,4 triazole derivative (TAZ), or the like.

  14 to 17 are diagrams for explaining the configuration of a pixel in which the first electrode 11, the EL layer 16, and the second electrode 17 are stacked.

  FIG. 14A shows an example in which the first electrode 11 is formed of a light-transmitting oxide conductive material, and the first electrode layer 31 is formed of an oxide conductive material such as ITO or an oxide conductive material containing silicon oxide. The second electrode layer 32 is formed of an oxide conductive material containing silicon oxide at a concentration of 1 to 15 atomic%. An EL layer 16 in which a hole injection layer or hole transport layer 41, a light emitting layer 42, an electron transport layer or an electron injection layer 43 are stacked is provided thereon. The second electrode 17 is formed of a third electrode layer 33 containing an alkali metal or alkaline earth metal such as LiF or MgAg and a fourth electrode layer 34 formed of a metal material such as aluminum. A pixel having this structure can emit light from the first electrode 11 side as indicated by an arrow in the drawing.

  FIG. 14B shows an example in which light is emitted from the second electrode 17. The first electrode 11 is a metal such as aluminum or titanium, or a metal material containing nitrogen at a concentration equal to or lower than the stoichiometric composition ratio with the metal. And the second electrode layer 32 formed of an oxide conductive material containing silicon oxide at a concentration of 1 to 15 atomic%. An EL layer 16 in which a hole injection layer or hole transport layer 41, a light emitting layer 42, an electron transport layer or an electron injection layer 43 are stacked is provided thereon. The second electrode 17 is formed by a third electrode layer 33 containing an alkali metal or alkaline earth metal such as LiF or CaF and a fourth electrode layer 34 formed of a metal material such as aluminum. By setting the thickness to 100 nm or less so that light can be transmitted, light can be emitted from the second electrode 17.

  FIG. 15A shows an example in which light is emitted from the first electrode 11, and the EL layer is stacked in the order of an electron transport layer or electron injection layer 43, a light emitting layer 42, a hole injection layer or a hole transport layer 41. Shows the configuration. The second electrode 17 is a second electrode layer 32 formed of an oxide conductive material containing silicon oxide at a concentration of 1 to 15 atomic% from the EL layer 16 side, a metal such as aluminum or titanium, or a chemical with the metal. The first electrode layer 31 is formed of a metal material containing nitrogen at a concentration equal to or lower than the stoichiometric composition ratio. The first electrode 11 is formed of a third electrode layer 33 containing an alkali metal or alkaline earth metal such as LiF or CaF and a fourth electrode layer 34 formed of a metal material such as aluminum. By setting the thickness to 100 nm or less so that light can be transmitted, light can be emitted from the first electrode 11.

  FIG. 15B shows an example in which light is emitted from the second electrode 17, and the EL layer is stacked in the order of the electron transport layer or electron injection layer 43, the light emitting layer 42, the hole injection layer or hole transport layer 41. Shows the configuration. The first electrode 11 has a structure similar to that shown in FIG. 15A, and is formed to be thick enough to reflect light emitted from the EL layer. The second electrode 17 includes a second electrode layer 32 formed of an oxide conductive material containing silicon oxide at a concentration of 1 to 15 atomic% from the EL layer 16 side, an oxide conductive material such as ITO, or silicon oxide. The first electrode layer 31 is formed of an oxide conductive material including the first electrode layer 31. In this structure, the hole injection layer 41 is formed of an inorganic metal oxide (typically molybdenum oxide or vanadium oxide), so that oxygen introduced when the second electrode layer 32 is formed is supplied. Thus, the hole injection property is improved, and the driving voltage can be lowered.

  FIGS. 16 and 17 show a pixel having a configuration capable of emitting light from both sides of the first electrode 11 and the second electrode 17.

  FIG. 16A illustrates an example in which the first electrode 11 is formed using a light-transmitting oxide conductive material, and the first electrode layer 31 is formed using an oxide conductive material such as ITO or an oxide containing silicon oxide. The second electrode layer 32 is formed of an oxide conductive material containing silicon oxide at a concentration of 1 to 15 atomic%. An EL layer 16 in which a hole injection layer or hole transport layer 41, a light emitting layer 42, an electron transport layer or an electron injection layer 43 are stacked is provided thereon. The second electrode 17 is formed by a third electrode layer 33 containing an alkali metal or alkaline earth metal such as LiF or CaF and a fourth electrode layer 34 formed of a metal material such as aluminum. By setting the thickness to 100 nm or less so that light can be transmitted, light can be emitted from both the second electrode 17 and the first electrode 11.

  FIG. 16B is formed by a third electrode layer 33 containing an alkali metal or alkaline earth metal such as LiF or CaF and a fourth electrode layer 34 formed of a metal material such as aluminum. Also, a thickness of 100 nm or less is set so that light can be transmitted. An EL layer is stacked thereon in this order: an electron transport layer or electron injection layer 43, a light emitting layer 42, a hole injection layer or a hole transport layer 41. The second electrode 17 includes a second electrode layer 32 formed of an oxide conductive material containing silicon oxide at a concentration of 1 to 15 atomic% from the EL layer 16 side, an oxide conductive material such as ITO, or silicon oxide. The first electrode layer 31 is formed of an oxide conductive material including the first electrode layer 31. Even with such a configuration, light can be emitted from both the second electrode 17 and the first electrode 11.

  17A and 17B show that both the first electrode layer 11 and the second electrode layer 17 are formed of the same material, that is, both electrodes are formed of an oxide conductive material. Is. In the first electrode layer 11, the first electrode layer 31 is formed of an oxide conductive material such as ITO or an oxide conductive material containing silicon oxide, and the second electrode layer 32 is formed of silicon oxide 1 to 15. It is formed of an oxide conductive material containing at a concentration of atomic%. The same applies to the second electrode 17, and the second electrode layer 32 is disposed on the side in contact with the EL layer 16. At this time, the hole injection layer of the EL layer 16 or the layer on the second electrode layer 32 side of the hole transport layer 41 is formed of a metal oxide (typically molybdenum oxide or vanadium oxide), and the electron transport layer or The layer on the second electrode layer 32 side of the electron injection layer 43 is preferably formed using an organic substance containing alkali metal or alkaline earth metal (typically, a benzoxazole derivative or a pyridine derivative).

  The barrier layer selectively removes the light-transmitting oxide conductive material from the surface of the hole injection electrode made of the oxide conductive material containing silicon oxide to increase the component ratio of the added silicon oxide. By forming. For example, a method of treating a surface with a solution capable of selectively removing a light-transmitting oxide conductive material, plasma treatment using one or more kinds of gases selected from hydrogen, oxygen, and fluorine, nitrogen, argon, and the like The barrier layer is formed by plasma treatment using an inert gas. The insulating or semi-insulating barrier layer thus obtained may be formed of silicon or silicon oxide, silicon or silicon oxide and a light-transmitting oxide conductive material, or silicon or silicon oxide and a light-transmitting material. It is preferable that the conductive oxide conductive material and carbon are combined.

  Constructed as described above, the hole injection electrode and the hole injection layer or hole transport layer that is an organic compound are not in direct contact with each other, thereby expressing the effect of the original work function of the hole injection electrode, The light emission characteristics can be improved by increasing the hole injection efficiency for the hole injection layer and further effectively using the carriers.

  FIG. 12 is a band model showing the contact between a conventional oxide conductive layer (CTO) and a hole injection layer (HIL). When the contact is not well formed, the band of the hole injection layer bends in the direction of creating a barrier against electrons due to the influence of the interface potential, and holes are accumulated near the interface. In addition, the work function of the oxide conductive film changes (in a decreasing direction) due to surface contamination, etc., and in such a case, the hole injection property is reduced, and the injected holes emit light. Since the contributing ratio is reduced, the current efficiency is reduced.

  13A and 13B show a state where an insulating or semi-insulating barrier film containing silicon or silicon oxide is formed at the interface between the oxide conductive layer (CTO) and the hole injection layer (HIL). It is a band model to explain. The barrier layer has a thickness that allows carriers to tunnel, that is, has a thickness of 0.5 to 5 nm. This barrier layer functions to flatten the band as shown in FIG. 13 (A) or bend downward as shown in FIG. 13 (B) to prevent holes from accumulating. As a result, the effect of increasing the ratio of the injected holes contributing to light emission can be obtained.

  2-6 is a figure which shows the process in which the light-emitting device in embodiment of this invention is manufactured. First, as shown in FIG. 1, in order to form a first electrode 11 and an input terminal portion extending in one direction on a main surface of a substrate 10 having an insulating surface such as a ceramic material such as glass, quartz, and alumina, or a synthetic material. The electrodes 12 are made of the same material. As shown in the drawing, by providing a plurality of first electrodes 11, one electrode of pixels arranged in a matrix is formed.

  When the first electrode 11 is a hole injection electrode, it has a laminated structure of at least two layers. Of these, the first electrode layer is mainly composed of indium tin oxide, zinc oxide, indium zinc oxide, zinc oxide or other oxide conductive material added with gallium, or titanium, tantalum, molybdenum, chromium, nickel, aluminum or aluminum. Or a conductive material containing nitrogen at a concentration less than the stoichiometric composition ratio with the metal. In the case of a light emitting device configured to extract light from the first electrode 11 side, it is desirable to use the oxide conductive material as described above.

  For the second electrode layer, indium tin oxide containing silicon oxide is used by a sputtering method using a target in which 2 to 10% by weight of silicon oxide is contained in ITO. In addition, an oxide conductive material containing silicon oxide and in which 2 to 20% zinc oxide (ZnO) is mixed with indium oxide may be used.

  Next, as shown in FIG. 3, auxiliary electrodes 13a and 13b are formed in the input terminal portion formation region of the first electrode and the connection / input terminal portion formation region of the second electrode. The auxiliary electrode is preferably formed of a conductive material having good heat sealability when connected to an external circuit, and may be formed of a metal material containing chromium, nickel, or the like.

  Next, as shown in FIG. 4, the insulating layer 14 is formed. The insulating layer 14 is formed with an opening of a through hole in accordance with a position where a pixel is formed corresponding to the first electrode. This insulating layer 14 is made of silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, amonium oxynitride or other inorganic insulating materials, or acrylic acid, methacrylic acid and derivatives thereof, polyimide, aromatic Inorganic siloxanes containing Si—O—Si bonds among silicon, oxygen, and hydrogen compounds formed from heat-resistant polymers such as aromatic polyamides, polybenzimidazole, or siloxane-based materials as starting materials. The hydrogen can be formed of an organic siloxane insulating material substituted with an organic group such as methyl or phenyl.

The opening of the insulating layer 14 can be formed by using an etching gas such as C ₄ F ₈ or CHF _{3 for} silicon oxide. For silicon nitride, an etching gas such as HBr or Cl ₂ can be used. By such etching treatment, indium tin oxide and tin oxide are removed from the surface of the indium tin oxide film containing silicon oxide, and a region having a relatively high concentration of silicon oxide or silicon compared to the inside of the film It can be formed near the surface.

  In FIG. 5, when an EL layer and a second electrode to be formed in a later process are formed, a partition wall 15 is formed in order to facilitate isolation between adjacent pixels. The shape of the partition wall 15 may be a so-called reverse tapered shape in which the dimension in the width direction at the top portion is longer than the bottom portion as shown as the partition wall 15 in FIG. 7, or as the partition wall 21 in FIG. A forward taper shape having a long dimension in the width direction at the bottom may be used, or a T-shape may be used. In any case, the partition wall 15 is formed so as to extend in a direction intersecting the first electrode so as to expose a portion corresponding to the pixel of the first electrode, and to be arranged at a predetermined interval. The partition wall 15 is made of a photosensitive organic resin material or siloxane-based material containing acrylic acid, methacrylic acid and derivatives thereof, polyimide, aromatic polyamide, polybenzimidazole, and other polymers. Inorganic siloxane containing Si-O-Si bond among compounds consisting of silicon, oxygen and hydrogen formed as starting material, and organic siloxane insulating material in which hydrogen on silicon is replaced by organic group such as methyl or phenyl Form with.

Thereafter, as shown in FIG. 6, an EL layer 16 is formed on the first electrode 11 exposed from the opening of the insulating layer 14. The EL layer 16 has a configuration in which a light emitting layer alone or a plurality of layers including a light emitting layer are stacked. For example, CuPc as the hole injection layer is MoO _x (x = 2 to 3) or PEDOT / PSS, α-NPD as the hole transport layer, Alq3: DMQd (DMQd: quinacridone derivative) as the light emitting layer, and as the electron transport layer Alq3 is formed.

  Before the EL layer 16 is formed, the first electrode 11 exposed from the opening of the insulating layer 14 (particularly, an oxide conductive material containing silicon or silicon oxide as the second electrode layer) is exposed. Thus, it is preferable to perform a treatment for increasing the degree of oxidation of silicon or silicon oxide deposited on the surface by performing oxygen plasma treatment or ultraviolet irradiation treatment. That is, it becomes possible to more reliably form a barrier layer that enhances the hole injection property and allows current to flow.

Next, the second electrode 17 is formed in a direction intersecting the first electrode 11 in the region where the EL layer 16 is formed on the first electrode 11. When the second electrode 17 is an electron injection electrode, the second electrode 17 is formed using a conductive material containing an alkali metal or an alkaline earth metal. For the electron injection electrode, a material having a small work function is selected in order to efficiently inject electrons into the EL layer, and a region containing an alkali metal or an alkaline earth metal such as Li, Ca, Mg is an electron injection layer in the EL layer or It is formed so as to be in contact with the electron transport layer.
In this manner, a region formed by sandwiching the EL layer 16 between the first electrode 11 and the second electrode 17 becomes a light emitting element, that is, a light emitting pixel is formed. Further, the second electrode 17 is disposed so as to extend to a region where the electrode 13b of the input terminal portion 19 is formed and to maintain an electrical connection.

  As described above, a panel in which the pixel portion 20 is formed using a light emitting element is formed. Thereafter, as shown in FIG. 9, a protective film 22 that prevents intrusion of moisture and the like is formed, and a sealing substrate 23 made of a ceramic material such as glass, quartz, or alumina or a synthetic material is fixed with an adhesive 24 for sealing. . The external input terminal portion is connected using the flexible printed wiring board 25 when connecting to an external circuit. Further, as shown in FIG. 10, a sealing can 26 may be used, and a desiccant 27 may be disposed therein, followed by fixing with a sealing adhesive 23 as shown in FIG. The protective film 22 may be formed of a laminate of carbon nitride and silicon nitride as a structure that improves the gas barrier property while reducing stress, in addition to the film formed of silicon nitride.

  FIG. 11 shows a modularized state in which a flexible printed wiring board 25 is fixed to the external input terminal portions 18 and 19 and is electrically connected to an external circuit board 29 on which a power supply circuit and a signal processing circuit are formed. Further, the mounting method of the driver IC 28 may be either COG or TAB, and FIG. 11 shows the case of TAB.

  FIG. 18 is a diagram showing a usage pattern of the light emitting device according to the present invention. FIG. 18A shows a completed form as a television receiver, and a display screen 303 is formed by the module shown in FIG. That is, the module shown in FIG. 11 is housed in a housing 301, and includes other components such as a speaker 304 and an operation switch 305. FIG. 18B shows a completed audio device that can be mounted on an automobile or the like, and a display screen 342 for displaying the operation state of the device is formed by the module shown in FIG. Yes. That is, the module shown in FIG. 11 is housed in a housing 341, and operation switches 343 and 344 are provided as other accessory equipment.

It is a top view explaining the structure of the light-emitting device which concerns on this invention. It is a top view explaining the manufacturing process of the light-emitting device which concerns on this invention. It is a top view explaining the manufacturing process of the light-emitting device which concerns on this invention. It is a top view explaining the manufacturing process of the light-emitting device which concerns on this invention. It is a top view explaining the manufacturing process of the light-emitting device which concerns on this invention. It is a top view explaining the manufacturing process of the light-emitting device which concerns on this invention. It is a longitudinal cross-sectional view which shows an example of the structure corresponding to the AB cut line of FIG. It is a longitudinal cross-sectional view which shows an example of the structure corresponding to the AB cut line of FIG. It is a longitudinal cross-sectional view explaining the structure of the light-emitting device which concerns on this invention. It is a longitudinal cross-sectional view explaining the structure of the light-emitting device which concerns on this invention. It is a schematic plan view showing a module in which an external circuit is connected to a panel in which a pixel portion is formed. It is a figure which shows the band model which shows the contact state of the conventional translucent oxide conductive layer and a hole injection layer. It is a figure which shows the band model explaining the state in which the insulating or semi-insulating barrier film containing silicon or silicon oxide was formed in the interface of a translucent oxide conductive layer and a hole injection layer. It is sectional drawing explaining the aspect of the laminated structure of the light emitting pixel which concerns on this invention. It is sectional drawing explaining the aspect of the laminated structure of the light emitting pixel which concerns on this invention. It is sectional drawing explaining the aspect of the laminated structure of the light emitting pixel which concerns on this invention. It is sectional drawing explaining the aspect of the laminated structure of the light emitting pixel which concerns on this invention. It is a figure explaining an example in the utilization form of the light-emitting device which concerns on this invention.

Claims (23)

  Between a hole injecting electrode including a first electrode layer made of a conductive material and a second electrode layer made of an oxide conductive material containing silicon or silicon oxide, and an electron injecting electrode A light emitting device comprising a layer formed by including an organic substance or an organic substance and an inorganic substance.   Between a hole injecting electrode including a first electrode layer made of a conductive material and a second electrode layer made of an oxide conductive material containing silicon or silicon oxide, and an electron injecting electrode A layer formed of an organic substance or an organic substance and an inorganic substance is provided, and a hole injection region or a hole injection transport region of the layer is provided in contact with the second electrode layer. Light-emitting device.   Between a hole injecting electrode including a first electrode layer made of a conductive material and a second electrode layer made of an oxide conductive material containing silicon or silicon oxide, and an electron injecting electrode A layer formed by including an organic substance or an organic substance and an inorganic substance, and a tunnel current can flow between the hole injection region or the hole injection transport region of the layer and the second electrode layer A light-emitting device having a thickness and an insulating or semi-insulating barrier layer.   Between a hole injecting electrode including a first electrode layer made of a conductive material and a second electrode layer made of an oxide conductive material containing silicon or silicon oxide, and an electron injecting electrode A layer formed by including an organic substance or an organic substance and an inorganic substance, and the hole injection efficiency between the hole injection region or the hole injection transport region of the layer and the second electrode layer is increased. A light-emitting device including an improved insulating or semi-insulating barrier layer.   Between a hole injecting electrode including a first electrode layer made of a conductive material and a second electrode layer made of an oxide conductive material containing silicon or silicon oxide, and an electron injecting electrode A layer formed by including an organic substance, or an organic substance and an inorganic substance, and containing the silicon or silicon oxide on the surface of the hole injection region or the hole injection transport region of the layer and the second electrode layer A light emitting device including a barrier layer.   Between a hole injecting electrode including a first electrode layer made of a conductive material and a second electrode layer made of an oxide conductive material containing silicon or silicon oxide, and an electron injecting electrode A layer formed by including an organic substance, or an organic substance and an inorganic substance, and containing the silicon or silicon oxide on the surface of the hole injection region or the hole injection transport region of the layer and the second electrode layer A light emitting device including a barrier layer.   7. The conductive material forming the first electrode layer according to claim 1 is an oxide conductive material containing silicon or silicon oxide, and silicon or silicon contained in the oxide conductive material is formed. The light-emitting device is characterized in that the concentration of silicon oxide is lower than the concentration of silicon or silicon oxide contained in the oxide conductive material forming the second electrode layer.   8. The light emitting device according to claim 1, wherein the oxide conductive material is one selected from indium tin oxide, zinc oxide, indium zinc oxide, and zinc oxide to which gallium is added. apparatus.   8. The light emission according to claim 1, wherein a ratio of silicon or silicon oxide contained in the oxide conductive material forming the second electrode layer is 1 to 15 atomic%. apparatus.   7. The conductive material forming the first electrode layer according to claim 1, wherein the conductive material is one selected from indium tin oxide, zinc oxide, indium zinc oxide, and zinc oxide to which gallium is added. A light emitting device characterized by that.   7. The light-emitting device according to claim 1, wherein the conductive material forming the first electrode layer is mainly aluminum or aluminum.   7. The conductive material forming the first electrode layer according to claim 1, wherein the conductive material contains a metal and nitrogen at a concentration equal to or less than the stoichiometric composition ratio with the metal. Light-emitting device.   The electrode of at least one of the pixels in which an organic substance that expresses electroluminescence or a medium containing an organic substance and an inorganic substance is interposed between an electrode extending in one direction and an electrode extending in a direction intersecting with the electrode, A hole injecting region or a hole injecting and transporting region of the medium formed from a second electrode layer that enhances hole injecting property and a first electrode layer having a lower resistivity than the second electrode layer; The light-emitting device, wherein the second electrode layer is provided adjacently.   At least one of the electrodes of a pixel in which an organic substance that expresses electroluminescence or a medium formed by including an organic substance and an inorganic substance is interposed between an electrode extending in one direction and an electrode extending in a direction intersecting with the electrode, A hole injecting region or a hole injecting and transporting region of the medium, the second electrode layer having a hole injecting property and a first electrode layer having a resistivity lower than that of the second electrode layer; A light-emitting device, wherein an insulating or semi-insulating barrier layer is provided with a thickness that allows a tunnel current to flow between the second electrode layers.   At least one of the electrodes of a pixel in which an organic substance that expresses electroluminescence or a medium formed by including an organic substance and an inorganic substance is interposed between an electrode extending in one direction and an electrode extending in a direction intersecting with the electrode, A hole injecting region or a hole injecting and transporting region of the medium, the second electrode layer having a hole injecting property and a first electrode layer having a resistivity lower than that of the second electrode layer; An insulating or semi-insulating barrier layer for improving hole injection efficiency is provided between the second electrode layers.   At least one of the electrodes of a pixel in which an organic substance that expresses electroluminescence or a medium formed by including an organic substance and an inorganic substance is interposed between an electrode extending in one direction and an electrode extending in a direction intersecting with the electrode, A hole injecting region or a hole injecting and transporting region of the medium, the second electrode layer having a hole injecting property and a first electrode layer having a resistivity lower than that of the second electrode layer; A light-emitting device, wherein a barrier layer containing silicon or silicon oxide is provided on a surface of the second electrode.   At least one of the electrodes of a pixel in which an organic substance that expresses electroluminescence or a medium formed by including an organic substance and an inorganic substance is interposed between an electrode extending in one direction and an electrode extending in a direction intersecting with the electrode, A hole injecting region or a hole injecting and transporting region of the medium, the second electrode layer having a hole injecting property and a first electrode layer having a resistivity lower than that of the second electrode layer; A light-emitting device, wherein a barrier layer containing silicon or silicon oxide is provided on a surface of the second electrode.   18. The conductive material forming the first electrode layer according to claim 13 is an oxide conductive material containing silicon or silicon oxide, and silicon contained in the oxide conductive material or The light-emitting device is characterized in that the concentration of silicon oxide is lower than the concentration of silicon or silicon oxide contained in the oxide conductive material forming the second electrode layer.   19. The light emitting device according to claim 13, wherein the second electrode layer is one type selected from indium tin oxide, zinc oxide, indium zinc oxide, and zinc oxide to which gallium is added. apparatus.   19. The light-emitting device according to claim 13, wherein a ratio of the silicon or silicon oxide is 1 to 15 atomic%.   The conductive material forming the first electrode layer according to any one of claims 13 to 17 is one selected from indium tin oxide, zinc oxide, indium zinc oxide, and zinc oxide to which gallium is added. A light emitting device characterized by that.   18. The light-emitting device according to claim 13, wherein the first electrode layer is mainly composed of aluminum or aluminum. 18. The light-emitting device according to claim 13, wherein the first electrode layer includes a metal and nitrogen at a concentration equal to or less than the stoichiometric composition ratio with the metal.

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