WO2010016512A1

WO2010016512A1 - Organic electroluminescent element, display device and illuminating device

Info

Publication number: WO2010016512A1
Application number: PCT/JP2009/063851
Authority: WO
Inventors: 勘治朗迫; 邦夫近藤
Original assignee: 昭和電工株式会社
Priority date: 2008-08-06
Filing date: 2009-08-05
Publication date: 2010-02-11
Also published as: TW201014444A

Abstract

Disclosed is an organic electroluminescent element (10) comprising: an anode layer (12); a cathode layer (15); a dielectric layer (14) arranged between the anode layer (12) and the cathode layer (15); a recessed part (16) so formed as to penetrate at least the dielectric layer (14); a light-emitting part (17) so formed as to be in contact with the inner surface of the recessed part (16); and a heat dissipating layer (13) containing alumina or the like, which is formed, for example, between the anode layer (12) and the cathode layer (15) for the purpose of dissipating the heat generated in the light-emitting part (17). The organic electroluminescent element is reduced in luminance variations due to uneven heat generation and has high luminous efficiency.

Description

Organic electroluminescent element, display device and lighting device

The present invention relates to, for example, an organic electroluminescent element used for a display device or a lighting device.

In recent years, devices using electroluminescence have increased in importance. As such a device, there is an organic electroluminescent element that emits light by forming a light emitting material made of an organic material in a layer and providing a pair of electrodes consisting of an anode and a cathode on the light emitting layer and applying a voltage. It attracts attention. An organic electroluminescent element is produced by injecting holes and electrons from the anode and the cathode, respectively, by applying a voltage between the anode and the cathode, and the injected electrons and holes are combined in the light emitting layer. Uses energy to emit light. That is, the device utilizes a phenomenon in which light is generated when the light-emitting material of the light-emitting layer is excited by the energy of the coupling and returns from the excited state to the ground state again.
When this organic electroluminescent element is used as a display device, since an organic substance is used as a light-emitting material, it is easy to generate light with high color purity by selecting an organic substance, and thus a wide color reproduction range can be obtained. There is the feature that it is. In addition, since it is self-luminous, it has the characteristics of high response speed and wide viewing angle. Further, because of its structure, it is easy to reduce the thickness, so that it has an advantage that a thin display device can be manufactured. Furthermore, since it is possible to emit white light and it is surface light emission, an application in which an organic electroluminescent element is incorporated in a lighting device has been proposed.

As a structure of such an organic electroluminescent element, for example, Patent Document 1 includes a dielectric layer inserted between a hole electrode injection layer and an electron injection electrode layer, and at least the dielectric layer and the electrode layer Cavity light emitting electroluminescent devices have been proposed that extend through one and apply an electroluminescent coating material to an internal cavity surface comprising a hole injection electrode region, an electron injection electrode region, and a dielectric region.
Further, Patent Document 2 discloses a metal nitride or metal carbide in an organic electroluminescence element in which a carrier transport layer and a light emitting layer using at least an organic material are laminated between a hole injection electrode and an electron injection electrode. There has been proposed an organic electroluminescence element characterized in that a heat dissipation layer is provided.

Special table 2003-522371 JP-A-8-185982

However, the cavity light-emitting electroluminescent device described in JP-T-2003-522371 has a sufficient countermeasure against the problem that the device is deteriorated due to heat generated during light emission and the durability is not necessarily guaranteed. Not a structure. In particular, when the device is used for illumination or the like, it is necessary to emit light with a large area and high luminance, so that the amount of heat generated per unit area becomes very large. Therefore, it is necessary to take further measures against heat generation.
In addition, in an organic electroluminescence element provided with a heat dissipation layer made of metal nitride or metal carbide, the metal nitride or metal carbide is an opaque material, and light transmission is blocked, resulting in a decrease in light emission efficiency.

In view of the above-described problems, an object of the present invention is to provide an organic electroluminescence device having high luminance efficiency with less luminance unevenness due to uneven heat generation.
Another object is to provide a display device having high contrast and resolution and high luminous efficiency.
Furthermore, another object is to provide an illuminating device with less luminance unevenness and high light emission efficiency.

The organic electroluminescent element of the present invention comprises a first electrode layer, a second electrode layer, a dielectric layer formed between the first electrode layer and the second electrode layer, and at least a dielectric layer. It has a recess formed through, a light emitting portion formed in contact with the inner surface of the recess, and a heat dissipation layer that dissipates heat generated from the light emitting portion.

Here, the heat dissipation layer is preferably formed between the first electrode layer and the second electrode layer. In this case, the heat dissipation layer preferably has a thickness of 50 nm to 200 nm.
Further, the heat dissipation layer is preferably formed in contact with at least one of the first electrode layer and the second electrode layer, and in this case, it preferably has a thickness of 0.2 μm to 1000 μm.
The heat dissipation layer is more preferably formed in accordance with the shape of the concave portion, and includes aluminum nitride, tantalum nitride, alumina, sapphire, beryllium oxide, magnesium oxide, diamond-like carbon, single crystal silicon, polycrystalline silicon, and amorphous silicon. More preferably, it contains at least one selected from silicon carbide and metal materials.

The heat dissipation layer preferably has a thermal conductivity of 10 W / (m · K) or more.

Further, the recess preferably has a substantially cylindrical shape penetrating the first electrode layer, the second electrode layer, the dielectric layer, and the heat dissipation layer. The first electrode layer, the second electrode layer, the dielectric layer In addition, it is preferable to form grooves that are substantially parallel to each other and penetrate through the heat dissipation layer, and preferably further penetrate at least one of the first electrode layer and the second electrode layer.

Further, the light emitting part preferably contains a phosphorescent material, and the phosphorescent material is preferably a phosphorescent polymer having a molecular weight of 1,000 to 2,000,000 in terms of weight average molecular weight. More preferably, the phosphor comprises a phosphorescent unit that emits phosphorescence and a carrier transporting unit that transports carriers in one molecule.

Furthermore, it is preferable that the first electrode layer and the second electrode layer are formed of an opaque material.

The display device of the present invention includes the organic electroluminescent element described above.

The lighting device of the present invention is characterized by including the organic electroluminescent element described above.

According to the present invention, it is possible to provide an organic electroluminescent device having high luminance efficiency and less luminance unevenness due to uneven heat generation.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view illustrating a first example of an organic electroluminescent element to which the exemplary embodiment is applied.
An organic electroluminescent element 10 shown in FIG. 1 includes an anode layer 12 as a first electrode layer, a heat dissipation layer 13, an insulating dielectric layer 14, and a cathode as a second electrode layer on a substrate 11. A structure in which the layer 15 is sequentially laminated is adopted. Moreover, it has the recessed part 16 formed penetrating the anode layer 12, the thermal radiation layer 13, the dielectric material layer 14, and the cathode layer 15, and it is light-emitted by being formed in contact with the inner surface of the recessed part 16, and applying a voltage. A light emitting unit 17 is included. In the light emitting portion 17, a light emitting material is applied to the inner surface of the recessed portion 16 without filling the entire recessed portion 16, thereby forming a second recessed portion 18.

The substrate 11 serves as a support for forming the anode layer 12, the heat dissipation layer 13, the dielectric layer 14, the cathode layer 15, and the light emitting portion 17. A material that satisfies the mechanical strength required for the organic electroluminescent element 10 is used for the substrate 11.
As a material of the substrate 11, when light is to be extracted from the substrate 11 side of the organic electroluminescent element 10, it is necessary to be transparent to visible light. Specifically, glass such as soda glass and alkali-free glass; transparent plastic such as acrylic resin, methacrylic resin, polycarbonate resin, polyester resin, and nylon resin; silicon and the like.
When it is not necessary to extract light from the substrate 11 side of the organic electroluminescent element 10, the material of the substrate 11 is not limited to a material transparent to visible light, and an opaque material can be used. Specifically, in addition to the above materials, copper (Cu), silver (Ag), gold (Au), platinum (Pt), tungsten (W), titanium (Ti), tantalum (Ta), or niobium (Nb) ), Alloys thereof, or materials made of stainless steel can also be used.
The thickness of the substrate 11 is preferably 0.1 mm to 10 mm, more preferably 0.25 mm to 2 mm, although it depends on the required mechanical strength.

The anode layer 12 applies voltage between the cathode layer 15 and injects holes into the light emitting portion 17. The material used for the anode layer 12 is not particularly limited as long as it has electrical conductivity, but preferably has a sheet resistance of 1000Ω or less in a temperature range of −5 ° C. to 80 ° C. More preferably, it is 100Ω or less. In addition, it is preferable that the electrical resistance does not change significantly with respect to the alkaline aqueous solution. Metal oxides, metals, and alloys can be used as materials that satisfy such conditions. Here, examples of the metal oxide include ITO (indium tin oxide) and IZO (indium-zinc oxide). Examples of the metal include stainless steel, copper (Cu), silver (Ag), gold (Au), platinum (Pt), tungsten (W), titanium (Ti), tantalum (Ta), niobium (Nb), and the like. . An alloy containing these metals can also be used. The thickness of the anode layer 12 is preferably 2 nm to 300 nm because high light transmittance is required when light is to be extracted from the substrate 11 side of the organic electroluminescent element 10. Further, when it is not necessary to extract light from the substrate 11 side of the organic electroluminescent element 10, it can be formed with a thickness of 2 nm to 2 mm, for example.

The heat dissipation layer 13 is for absorbing heat generated by the light emitting unit 17 to emit light and dissipating heat. In the organic electroluminescent element 10 shown in FIG. 1, it is formed between an anode layer 12 as a first electrode layer and a cathode layer 15 as a second electrode layer. From the viewpoint of efficiently absorbing heat, the heat dissipation layer 13 is preferably formed in contact with the light emitting portion 17. The heat absorbed by the heat radiating layer 13 conducts heat in the heat radiating layer 13 and generates heat conduction mainly on the substrate 11 side, so that heat can be efficiently radiated from the substrate 11. As a result, in the surface of the organic electroluminescent element 10, luminance unevenness due to non-uniform heat generation can be made difficult to occur.

The heat dissipation layer 13 preferably has a thermal conductivity at room temperature of 10 W / (m · K) or more, and more preferably 15 W / (m · K) or more. When the thermal conductivity at room temperature is less than 10 W / (m · K), it is difficult to perform efficient heat dissipation.
Specific examples of materials that can be used for the heat dissipation layer 13 include highly thermally conductive metal nitrides such as aluminum nitride and tantalum nitride; metal oxides such as alumina, sapphire, beryllium oxide, and magnesium oxide; diamond-like carbon (DLC: Diamond Like Carbon); single crystal silicon; polycrystalline silicon; amorphous silicon; silicon carbide. A mixture of these may also be used. Alternatively, a metal or metal alloy having excellent thermal conductivity can be used. For example, manganese (Mn), nickel (Ni), aluminum (Al), copper (Cu), zinc (Zn), indium (In), tantalum (Ta), niobium (Nb), tungsten (W), titanium (Ti ), Molybdenum (Mo), gold (Au), silver (Ag), iron (Fe), platinum (Pt), zirconium (Zr), germanium (Ge), magnesium (Mg), etc., or alloys thereof Is done. Alternatively, materials that are excellent in thermal conductivity but cannot be formed into a film by themselves because they are in powder form should be used after being mixed or dispersed in a resin and then formed into a film. Can do. For example, carbon tubes, particulate alumina, powdered diamond and the like mixed and dispersed in a polymer resin (polystyrene, polyimide, polypropylene, polyethylene, polyethylene terephthalate, polymethacrylic acid, polycarbonate), and the like. Among these materials, many metal materials are particularly excellent in thermal conductivity. For example, aluminum (Al), copper (Cu), tantalum (Ta), gold (having a thermal conductivity of 150 W / (m · K) or more ( Au), silver (Ag), magnesium (Mg) and the like can be used particularly preferably.

The thickness of the heat dissipation layer 13 is preferably 50 nm to 200 nm when the heat dissipation layer 13 is provided between the anode layer 12 and the cathode layer 15 as in the organic electroluminescent device 10 shown in FIG. When the heat dissipation layer 13 is 50 nm or less, the distance between the anode layer 12 and the cathode layer 15 becomes too narrow, and a short circuit is likely to occur between the anode layer 12 and the cathode layer 15, so that stable driving is difficult. In the case where the heat dissipation layer 13 is provided between the anode layer 12 and the dielectric layer 14 as in the organic electroluminescent element 10 shown in FIG. 1, the heat dissipation layer 13 is made of a conductive material such as a metal material. In some cases, the work function of the heat dissipation layer 13 is preferably higher than the work function of the anode layer 12. By doing so, it becomes easy to preferentially inject holes between the anode layer 12 and the light emitting portion 17, so that it is easy to prevent a short circuit from occurring. Further, in a form in which the heat dissipation layer 13 is provided not between the anode layer 12 and the dielectric layer 14 but between the dielectric layer 14 and the cathode layer 15, the work function of the heat dissipation layer 13 is higher than the work function of the cathode layer 15. Preferably it is low. By doing so, it becomes easy to preferentially inject electrons between the cathode layer 15 and the light emitting portion 17, and thus it becomes easy to prevent a short circuit from occurring similarly. If the heat dissipation layer 13 is 200 nm or more, the drive voltage may be too high.
In the case where the heat radiation layer 13 is provided outside the anode layer 12 and the cathode layer 15 as in the organic

electroluminescent elements

20, 30, and 40 described later in FIGS. 3 to 5, the thickness of the heat radiation layer 13 is provided. Is preferably in the range of 0.2 μm to 1000 μm, and more preferably in the range of 0.5 μm to 500 μm. A thicker heat-dissipating layer 13 has higher heat conduction, which is preferable from the viewpoint of heat absorption and heat dissipation.

The dielectric layer 14 is provided between the anode layer 12 and the cathode layer 15, separates and insulates the anode layer 12 and the cathode layer 15 at a predetermined interval, and applies a voltage to the light emitting unit 17. It is. Therefore, the dielectric layer 14 needs to be a high resistivity material, and the electrical resistivity is required to be 10 ⁸ Ωcm or more, preferably 10 ¹² Ωcm or more. Specific examples of the material include metal nitrides such as silicon nitride, boron nitride, and aluminum nitride; metal oxides such as silicon oxide and aluminum oxide, but other polymer compounds such as polyimide, polyvinylidene fluoride, and parylene. Can also be used. The thickness of the dielectric layer 14 preferably does not exceed 1 μm in order to suppress the total thickness of the organic electroluminescent element 10. In addition, the narrower the distance between the anode layer 12 and the cathode layer 15, the lower the voltage required for light emission, so the thinner dielectric layer 14 is more preferable from this viewpoint. However, if the thickness is too thin, the dielectric strength may not be sufficient for the voltage for driving the organic electroluminescent element 10. Here, the dielectric strength is preferably such that the current density of the current flowing between the anode layer 12 and the cathode layer 15 is 0.1 mA / cm ² or less when the light emitting portion 17 is not formed, and 0.01 mA. / Cm ² or less is more preferable. In addition, since it is preferable to withstand a voltage exceeding 2 V with respect to the driving voltage of the organic electroluminescent element 10, for example, when the driving voltage is 5 V, the anode layer 12 and the anode layer 12 are not formed in a state where the light emitting portion 17 is not formed. It is necessary to satisfy the above current density when a voltage of about 7 V is applied between the cathode layers 15. The thickness of the dielectric layer 14 satisfying this is preferably 10 nm to 500 nm, more preferably 50 nm to 200 nm.

The cathode layer 15 applies a voltage between the anode layer 12 and injects electrons into the light emitting portion 17. The material used for the cathode layer 15 is not particularly limited as long as it has electrical conductivity like the anode layer 12, but a material having a low work function and being chemically stable is preferable. . The work function is preferably −2.9 eV or less in view of chemical stability. Specifically, materials such as Al, MgAg alloy, Al and alkali metal alloys such as AlLi and AlCa can be exemplified. The thickness of the cathode layer 15 is preferably 10 nm to 1 μm, more preferably 50 nm to 500 nm.

Further, a cathode buffer layer (not shown) may be provided adjacent to the cathode layer 15 for the purpose of increasing the electron injection efficiency by lowering the electron injection barrier from the cathode layer 15 to the light emitting portion 17. The cathode buffer layer is required to have a work function lower than that of the cathode layer 15, and a metal material is preferably used. For example, alkali metals (Na, K, Rb, Cs), alkaline earth metals (Sr, Ba, Ca, Mg), rare earth metals (Pr, Sm, Eu, Yb), or fluorides or chlorides of these metals, A simple substance selected from oxides or a mixture of two or more can be used. The thickness of the cathode buffer layer is preferably from 0.05 nm to 50 nm, more preferably from 0.1 nm to 20 nm, and even more preferably from 0.5 nm to 10 nm.

The concave portion 16 is for applying the light emitting portion 17 on the inner surface and taking out light from the light emitting portion 17. The concave portion 16 is an anode layer 12 that is a first electrode layer, and a cathode layer 15 that is a second electrode layer. The dielectric layer 14 and the heat dissipation layer 13 are formed so as to penetrate therethrough. The light emitted from the light emitting portion 17 by providing the concave portion 16 in this manner propagates through the concave portion 16 and can be extracted in both directions on the substrate 11 side and the cathode layer 15 side. Here, since the recess 16 is formed so as to penetrate the anode layer 12, the heat dissipation layer 13, the dielectric layer 14, and the cathode layer 15, in the anode layer 12 and the second electrode layer which are the first electrode layers. Light can be extracted even when a certain cathode layer 15 is formed of an opaque material.

Here, the shape of the concave portion 16 can be, for example, a substantially cylindrical shape, but is not limited thereto, and may be a shape that forms a groove shape that is substantially parallel to each other. When the recess 16 has a substantially cylindrical shape, the diameter is preferably 0.1 μm to 20 μm, and the distance between centers is preferably 0.2 μm to 40 μm. More preferably, the diameter is 0.1 μm to 10 μm, and the center-to-center distance is 0.2 μm to 20 μm. In the present embodiment, when the diameter of the recess 16 is 0.2 μm, the center-to-center spacing can be set to 0.3 μm to 1 μm, for example. When the recesses 16 are formed in a substantially parallel groove shape, the groove width is preferably 0.1 μm to 20 μm, and the interval between the groove centers is preferably 0.3 μm to 40 μm.
In the structure of the organic electroluminescent element 10 shown in FIG. 1, at least one of the anode layer 12 and the cathode layer 15 penetrates by forming the recess 16, so that light is emitted strongly at the edge portions of the anode layer 12 and the cathode layer 15. However, the light emission intensity at the center tends to be weak. Therefore, from this point of view, when the diameter and groove width of the recess 16 are 20 μm or more, the central portion of the recess 16 is likely to be in a non-lighting state, and as a result, the luminance per unit area of the organic electroluminescent element 10 is likely to decrease.

The light emitting portion 17 is a light emitting material that emits light when a voltage is applied. As described above, the light emitting portion 17 is applied to the inner surface of the recess 16 so as to form the second recess 18 by providing the light emitting material in contact with the recess 16. The In the light emitting unit 17, the holes injected from the anode layer 12 and the electrons injected from the cathode layer 15 are recombined to emit light.

As the material of the light emitting portion 17, either a low molecular compound or a high molecular compound can be used. For example, the luminescent low molecular weight compound and the luminescent high molecular weight compound described in Hiroshi Omori: Applied Physics, Vol. 70, No. 12, pp. 1419-1425 (2001) can be exemplified.

However, in this embodiment, a material excellent in applicability is preferable. That is, in the structure of the organic electroluminescent element 10 in the present embodiment, in order for the light emitting portion 17 to emit light stably in the recess 16, the light emitting portion 17 is in uniform contact with the inner surface of the recess 16 and the film thickness is uniformly formed. It is preferable that the coverage is improved. If the light emitting portion 17 is formed without using a material having excellent coating properties, the light emitting portion 17 is not in contact with the entire recess 16 or the film thickness of the inner surface of the recess 16 is not uniform. For this reason, variations in the brightness of light emitted from the recess 16 are likely to occur.
Moreover, in order to form the light emission part 17 uniformly in the recessed part 16, it is preferable to carry out by the apply | coating method. That is, in the coating method, it is easy to embed ink containing a light-emitting material in the concave portion 16, and thus it is possible to form a film with improved coverage even on a surface having irregularities. In the coating method, materials having a weight average molecular weight of 1,000 to 2,000,000 are preferably used mainly for the purpose of improving coating properties. Moreover, in order to improve applicability | paintability, coating property improvement additives, such as a leveling agent and a defoaming agent, can also be added, and binder resin with few charge trap ability can also be added.

Specifically, examples of the material having excellent coatability include, for example, an arylamine compound having a predetermined structure and a molecular weight of 1500 to 6000 as disclosed in JP-A-2007-86639, and JP-A 2000-034476. Examples thereof include the predetermined polymeric fluorescent substances.
Here, among materials having excellent coating properties, a light-emitting polymer compound is preferable in terms of simplifying the manufacturing process of the organic electroluminescent element 10, and a phosphorescent compound is preferable in terms of high light emission efficiency. Therefore, a phosphorescent polymer compound is particularly preferable. In addition, it is also possible to add a low molecular light emitting material (for example, molecular weight 1000 or less) in the range which does not impair the applicability | paintability by mixing several materials. In this case, the addition amount of the low molecular light emitting material is preferably 30 wt% or less.
The light-emitting polymer compound can be classified into a conjugated light-emitting polymer compound and a non-conjugated light-emitting polymer compound, and among them, the non-conjugated light-emitting polymer compound is preferable.
For the above reason, the light-emitting material used in this embodiment is particularly preferably a phosphorescent non-conjugated polymer compound (a light-emitting material that is both a phosphorescent polymer and a non-conjugated light-emitting polymer compound). .

The light emitting portion 17 in the organic electroluminescent device 10 of the present invention is preferably a phosphorescent polymer (in which a phosphorescent unit emitting phosphorescence and a carrier transporting unit transporting carriers are included in one molecule ( A phosphorescent material). The phosphorescent polymer can be obtained by copolymerizing a phosphorescent compound having a polymerizable substituent and a carrier transporting compound having a polymerizable substituent. The phosphorescent compound is a metal complex containing a metal element selected from iridium (Ir), platinum (Pt), and gold (Au), and among them, an iridium complex is preferable.

Examples of the polymerizable substituent in the phosphorescent compound include a urethane (meth) acrylate group such as a vinyl group, an acrylate group, a methacrylate group, and a methacryloyloxyethyl carbamate group, a styryl group and a derivative thereof, a vinylamide group and a derivative thereof, and the like. Among them, vinyl group, methacrylate group, styryl group and derivatives thereof are preferable. These substituents may be bonded to the metal complex via an organic group having 1 to 20 carbon atoms which may have a hetero atom.
A carrier transporting compound having a polymerizable substituent is a compound in which one or more hydrogen atoms in an organic compound having one or both of a hole transporting property and an electron transporting property are substituted with a polymerizable substituent. Can be mentioned.

The polymerizable substituent in the carrier transporting compound is a vinyl group. The vinyl group is a urethane (meth) acrylate group such as an acrylate group, a methacrylate group, or a methacryloyloxyethyl carbamate group, a styryl group and its derivative, a vinylamide group and its derivative. A compound substituted with a polymerizable substituent such as may be used. These polymerizable substituents may be bonded via an organic group having 1 to 20 carbon atoms which may have a hetero atom.

The polymerization method of the phosphorescent compound having a polymerizable substituent and the carrier transporting compound having a polymerizable substituent may be any of radical polymerization, cationic polymerization, anionic polymerization, and addition polymerization, but radical polymerization is preferred. The molecular weight of the polymer is preferably 1,000 to 2,000,000, more preferably 5,000 to 1,000,000 in terms of weight average molecular weight. The molecular weight here is a molecular weight in terms of polystyrene measured using a GPC (gel permeation chromatography) method.

The phosphorescent polymer may be a copolymer of one phosphorescent compound and one carrier transporting compound, one phosphorescent compound and two or more carrier transporting compounds, or two. The above phosphorescent compound may be copolymerized with a carrier transporting compound.

The arrangement of the monomer in the phosphorescent polymer may be any of random copolymer, block copolymer, and alternating copolymer, the number of repeating units of the phosphorescent compound structure is m, and the repeating unit of the carrier transporting compound structure When the number is n (m, n is an integer of 1 or more), the ratio of the number of repeating units of the phosphorescent compound structure to the total number of repeating units, that is, the value of m / (m + n) is 0.001 to 0.00. 5 is preferable, and 0.001 to 0.2 is more preferable.

More specific examples and synthesis methods of phosphorescent polymers are disclosed in, for example, JP-A Nos. 2003-342325, 2003-119179, 2003-113246, and 2003-206320. JP-A-2003-147021, JP-A-2003-171391, JP-A-2004-346212, JP-A-2005-97589, and JP-A-2007-305734.

The light emitting portion 17 of the organic electroluminescent element 10 in the present embodiment preferably includes the above-described phosphorescent compound, but a hole transporting compound or an electron transporting compound is used for the purpose of supplementing the carrier transporting property of the light emitting portion 17. It may be included. As the hole transporting compound used for these purposes, for example, TPD (N, N′-dimethyl-N, N ′-(3-methylphenyl) -1,1′-biphenyl-4,4′diamine) , Α-NPD (4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl), m-MTDATA (4,4 ′, 4 ″ -tris (3-methylphenylphenylamino) And low molecular triphenylamine derivatives such as triphenylamine). In addition, polyvinylcarbazole, a triphenylamine derivative obtained by introducing a polymerizable functional group into a polymer; a polymer compound having a triphenylamine skeleton disclosed in JP-A-8-157575; polyparaphenylene vinylene, And polydialkylfluorene. Examples of the electron transporting compound include low molecular weight materials such as quinolinol derivative metal complexes such as Alq3 (aluminum triskinolinolate), oxadiazole derivatives, triazole derivatives, imidazole derivatives, triazine derivatives, and triarylborane derivatives. Can be mentioned. Further, a polymer obtained by introducing a polymerizable functional group into the above low molecular electron transporting compound, for example, a known electron transporting compound such as poly PBD disclosed in JP-A-10-1665 is exemplified. .

Further, the light emitting portion 17 can be formed even when a light emitting low molecular weight compound is used as the light emitting material used for the light emitting portion 17 instead of the light emitting polymer compound described above. In addition, the above-described light-emitting polymer compound can be added as a light-emitting material, and a hole-transporting compound or an electron-transporting compound can also be added.
Specific examples of the hole transporting compound in this case include, for example, TPD, α-NPD, m-MTDATA, phthalocyanine complex, DTDPFL, spiro-TPD, TPAC, PDA described in JP-A-2006-76901. Etc.

Specific examples of the electron transport compound include BPhen, BCP, OXD-7, TAZ and the like described in JP-A-2006-76901.

Also, for example, a compound having a bipolar molecular structure having a hole transporting property and an electron transporting property in one molecule described in JP-A-2006-273792 can be used.

In the organic electroluminescent element 10 described in detail above, in the organic electroluminescent element 10 shown in FIG. 1, the light emitting portion 17 is in contact with the concave portion 16 to form the second concave portion 18 by providing the light emitting material, and Although the bottom part of the 2nd recessed part 18 is formed so that it may be located in the location near the bottom part of the recessed part 16, it is not restricted to this.

FIGS. 2A to 2D are diagrams for explaining other forms of the shape of the light-emitting portion 17.
In the organic electroluminescent element 10 a shown in FIG. 2A, the depth of the second recess 18 is shallow, and the bottom of the second recess 18 is formed so as to be located closer to the top than the bottom of the recess 16. ing. Further, in the organic electroluminescent element 10 b shown in FIG. 2B, the second recess 18 is not formed, and the recess 16 is completely filled with the light emitting portion 17, and the upper surface of the light emitting portion 17 is the upper surface of the cathode layer 15. Is consistent with Furthermore, in the organic electroluminescent element 10c shown in FIG. 2C, the second concave portion 18 is not formed, the concave portion 16 is completely filled with the light emitting portion 17, and the upper surface thereof has a convex shape. Further, in the organic electroluminescent element 10 d shown in FIG. 2D, the second recess 18 is formed, but the depth of the second recess 18 is shallow, and the bottom of the second recess 18 is the bottom of the recess 16. The light emitting portion 17 is formed so as to be developed not only inside the concave portion 16 but also on the upper surface of the cathode layer 15.
Also in the

organic electroluminescent elements

10a, 10b, 10c, and 10d shown in FIGS. 2A to 2D, the light emitted from the light emitting section 17 propagates inside the light emitting section 17, and the organic electroluminescent elements described above are used. 10, it can be taken out from both the substrate 11 side and the cathode layer 15 side.

The shape of the light emitting portion 17 described in FIG. 1 and FIGS. 2A to 2D can be selected depending on the cross-sectional structures of the anode layer 12 and the cathode layer 15, for example.
For example, as in the organic electroluminescent device 10 described with reference to FIG. 1, the second recess 18 is preferably formed when the cathode layer 15 is penetrated by the recess 16 and the upper part is opened. Further, in a structure in which the light emitting portion 17 is covered with the cathode layer 15 as in an organic electroluminescent element 40 as shown in FIG. 5 described later, the cathode layer 15 is formed after the light emitting portion 17 is formed. Therefore, it is preferable to form the second recess 18 small or not because the coverage is improved when the cathode layer 15 is formed.

In the organic electroluminescent element 10, the heat dissipation layer 13 is provided between the anode layer 12 and the dielectric layer 14. However, the present invention is not limited to this, and there is no particular limitation on the location.

FIG. 3 is a cross-sectional view illustrating a second example of an organic electroluminescent element to which the exemplary embodiment is applied.
The organic electroluminescent device 20 shown in FIG. 3 is different from the organic electroluminescent device 10 shown in FIG. 1 in that a heat dissipation layer 13 is provided between the substrate 11 and the anode layer 12 and is in contact with the anode layer 12. Is formed. Even in such a structure, the heat generated from the light emitting portion 17 is absorbed by the heat dissipation layer 13, and the heat transferred through the heat dissipation layer 13 is dissipated mainly from the substrate 11 side.

Further, in the organic electroluminescent device 10 shown in FIG. 1 and the organic electroluminescent device 20 shown in FIG. 3, the heat dissipation layer 13 is provided only in one layer, but the invention is not limited to this, and a plurality of layers may be provided. .

FIG. 4 is a cross-sectional view illustrating a third example of the organic electroluminescent element to which the exemplary embodiment is applied.
In the organic electroluminescent element 30 shown in FIG. 4, the heat dissipation layer 13 is provided between the substrate 11 and the anode layer 12, is formed in contact with the anode layer 12, and is laminated on the cathode layer 15. Are further provided in contact with each other. In this case, two layers of the heat dissipation layer 13 are formed. The heat dissipating layer 13 provided between the substrate 11 and the anode layer 12 dissipates heat mainly on the substrate 11 side, and the heat dissipating layer 13 laminated on the cathode layer 15 mainly directly from the heat dissipating layer 13. Heat can be dissipated.
Although not shown, the heat radiation layer 13 may be provided between the anode layer 12 and the cathode layer 15 and at a plurality of locations outside the anode layer 12 and the cathode layer 15.

Further, in the organic

electroluminescent elements

10, 10a, 10b, 10c, 10d, 20, 30 described with reference to FIGS. 1 to 4, the recess 16 includes the anode layer 12, the heat dissipation layer 13, the dielectric layer 14, and the cathode layer 15. However, the present invention is not limited to this. In order for the light emitting portion 17 to emit light, it is sufficient that at least the dielectric layer 14 penetrates through the recess 16. However, the recess 16 desirably has a structure that penetrates at least one of the anode layer 12 and the cathode layer 15.

FIG. 5 is a cross-sectional view illustrating a fourth example of an organic electroluminescent element to which the present exemplary embodiment is applied.
In the organic electroluminescent element 40 shown in FIG. 5, the recess 16 penetrates the heat dissipation layer 13, the anode layer 12, and the dielectric layer 14, but does not penetrate the cathode layer 15. And the recessed part 16 is filled with the light emission part 17, and the 2nd recessed part 18 is not formed. Further, the cathode layer 15 is formed in a so-called solid film shape so as to be laminated on the dielectric layer 14. By forming the cathode layer 15 in this way, the recess 16 is covered. Even if the light emitting part 17 is not applied to the inner surface of the recessed part 16 so as to form the second recessed part 18, the light emitted by the light emitting part 17 propagates inside the light emitting part 17, and the above-described organic electroluminescent element 10, Similarly to 20 and 30, it can be taken out from both the substrate 11 side and the cathode layer 15 side. However, in the case of this organic electroluminescent element 40, since the cathode layer 15 is a solid film and covers the light emitting portion 17, light is extracted from the cathode layer 15 side unless the cathode layer 15 is transparent to visible light. It is not possible.

FIG. 6 is a cross-sectional view illustrating a fifth example of the organic electroluminescent element to which the exemplary embodiment is applied.
In the organic electroluminescent device 50 shown in FIG. 6, the recess 16 penetrates the heat dissipation layer 13, the dielectric layer 14, and the cathode layer 15, but does not penetrate the anode layer 12. The light emitting unit 17 forms a second recess 18. Even when the anode layer 12 is formed in this way, the light emitted from the light emitting portion 17 can be extracted from both the substrate 11 side and the cathode layer 15 side. However, when it is desired to extract light from the anode layer 12 side, the anode layer 12 cannot extract light from the substrate 11 side unless it is transparent to visible light.

Further, FIG. 7 is a cross-sectional view illustrating a sixth example of an organic electroluminescent element to which the present exemplary embodiment is applied.
In the organic electroluminescent element 60 shown in FIG. 7, the recess 16 penetrates the heat dissipation layer 13 and the dielectric layer 14, but does not penetrate the anode layer 12 and the cathode layer 15. And the recessed part 16 is filled with the light emission part 17, and the 2nd recessed part 18 is not formed. Further, the anode layer 12 is formed in a so-called solid film shape so as to be laminated on the substrate 11. Further, the cathode layer 15 is formed in a so-called solid film shape so as to be laminated on the dielectric layer 14, and has a structure covering the recess 16. Even when the anode layer 12 and the cathode layer 15 are formed in this way, the light emitted from the light emitting portion 17 can be extracted from both the substrate 11 side and the cathode layer 15 side. However, in order to extract light from the substrate 11 side, the anode layer 12 needs to be transparent to visible light. Similarly, when it is desired to extract light from the cathode layer 15 side, the cathode layer 15 needs to be transparent to visible light.

Further, in the organic electroluminescent device 10 shown in FIG. 1, when the heat dissipation layer 13 is provided between the anode layer 12 and the cathode layer 15, the heat dissipation layer 13 is in contact with at least one of the anode layer 12 and the cathode layer 15. However, the present invention is not limited to this, and it may not be in contact.

FIG. 8 is a cross-sectional view illustrating a seventh example of an organic electroluminescent element to which the present exemplary embodiment is applied.
In the organic electroluminescent element 70 shown in FIG. 8, two dielectric layers are formed, and the heat dissipation layer 13 is formed between the

dielectric layers

14a and 14b having the two-layer structure. Even in such a structure, the heat generated from the light emitting portion 17 is absorbed by the heat dissipation layer 13, and the heat transferred through the heat dissipation layer 13 can be dissipated from the substrate 11 and the cathode layer 15 side.

FIG. 9 is a cross-sectional view illustrating an eighth example of an organic electroluminescent element to which the present exemplary embodiment is applied.
In the organic electroluminescent element 80 shown in FIG. 9, an anode layer 12, a heat dissipation layer 13, and a dielectric layer 14 are sequentially formed on a substrate 11. The light emitting material that forms the light emitting portion 17 is also developed from the recess 16 to the upper surface of the dielectric layer 14. That is, the light emitting material forming the light emitting portion 17 is continuously extended from the concave portion 16 between the dielectric layer 14 and the cathode layer 15. Further, the cathode layer 15 is formed so as to be further laminated on the light emitting material, and is formed in a so-called solid film shape. Even in such a structure, the heat generated from the light emitting portion 17 is absorbed by the heat dissipation layer 13, and the heat transferred through the heat dissipation layer 13 can be dissipated from the substrate 11 and the cathode layer 15 side.

As described above in detail, in the organic electroluminescent device of the present embodiment, the conventional sandwich composed of the anode layer, the light emitting portion, the cathode layer, etc., without providing the recesses 16 with respect to the position and number of the heat radiation layers 13. The degree of freedom is higher than that of the organic electroluminescent device having the structure. That is, in the organic electroluminescence device having a sandwich structure, the entire surface is a light emitting area, and therefore a heat dissipation layer can be inserted only on the back surface of the back electrode, and even when inserted, only a small area can be inserted from the viewpoint of light emission efficiency. Moreover, even if only a small area is inserted, the luminous efficiency is reduced. On the other hand, in the organic electroluminescent element of the present embodiment, it is possible to provide a heat dissipation layer in any region other than the portion where the recess 16 is provided. That is, the heat dissipation layer can be formed in conformity with the shape of the recess, so that the effect of heat dissipation is high, and it is easy to prevent unevenness in the heat generation from occurring in the organic electroluminescent element and uneven brightness. And it becomes easy to raise luminous efficiency. Further, since a part of the heat radiation layer 13 is in direct contact with the light emitting unit 17, it is possible to effectively dissipate heat from the light emitting unit 17. Furthermore, there is no restriction | limiting in particular in the location in which the thermal radiation layer 13 is provided, Since it can provide in several places, it is easy to improve the thermal radiation effect.

In addition, it is possible to use a transparent material as a heat dissipation layer in order to prevent a decrease in luminous efficiency in a conventional organic electroluminescent device with a sandwich structure, but transparent and highly heat conductive materials such as sapphire and quartz It is an expensive material and is not practical for application. On the other hand, in the organic electroluminescent element of this embodiment, since an opaque material can be used, it is possible to use an inexpensive material with a high degree of freedom in material selection.

In the organic

electroluminescent elements

10, 10a, 10b, 10c, 10d, 20, 30, 40, 50, 60, 70, 80 described in detail above, the anode layer is formed on the lower side when the substrate 11 side is the lower side. However, the present invention is not limited to this, but the anode layer 12 and the cathode layer 15 are not limited to this. An exchanged structure may be used. That is, when the substrate 11 side is the lower side, the cathode layer 15 may be formed on the lower side, and the anode layer 12 may be formed on the upper side with the dielectric layer 14 interposed therebetween.
Further, in the organic

electroluminescent elements

10, 10a, 10b, 10c, 10d, 50, 60, 80, the heat dissipation layer 13 is on the lower side and the dielectric layer 14 is formed on the upper side. The body layer 14 may be on the lower side and the heat dissipation layer 13 may be on the upper side.

Next, a method for manufacturing an organic electroluminescent element will be described by taking the case of the organic electroluminescent element 10 described in FIG. 1 as an example.
10A to 10F are diagrams illustrating a method for manufacturing the organic electroluminescent element 10 to which the exemplary embodiment is applied.
First, the anode layer 12, the heat dissipation layer 13, the dielectric layer 14, and the cathode layer 15 are formed in this order on the substrate 11 (FIG. 10A). In order to form these layers, resistance heating vapor deposition, electron beam vapor deposition, sputtering, ion plating, or the like can be used. In addition, when a coating film forming method, that is, a method in which a target material is dissolved in a solvent and applied to a substrate and drying is possible, a spin coating method, a dip coating method, an ink jet method, a printing method, a spray method It is also possible to form a film using a method such as a dispenser method. The cathode buffer layer can also be formed by the same method.

Next, the recess 16 is formed so as to penetrate the anode layer 12, the heat dissipation layer 13, the dielectric layer 14, and the cathode layer 15. To form the recess 16, for example, a method using lithography can be used. In order to do this, first, a resist solution is applied on the cathode layer 15, and the excess resist solution is removed by spin coating or the like to form a resist layer 61 (FIG. 10B).

Then, when a mask (not shown) on which a predetermined pattern for forming the concave portion 16 is drawn is applied, and exposure is performed with ultraviolet rays (UV: Ultra Violet), electron beams (EB: Electron Beam), etc., the resist layer A predetermined pattern 62 corresponding to the concave portion 16 is exposed on 61 (FIG. 10C).

Next, when the exposed portion of the resist layer 61 is removed using a developing solution, the resist layer 61 in the portion of the pattern 62 is removed (FIG. 10D).

Next, the exposed portion of the cathode layer 15 is removed by etching, and a recess 16 is formed so as to penetrate the anode layer 12, the heat dissipation layer 13, the dielectric layer 14, and the cathode layer 15 (FIG. 10E). As the etching, either dry etching or wet etching can be used. At this time, the shape of the recess 16 can be controlled by combining isotropic etching and anisotropic etching. As dry etching, reactive ion etching (RIE) or inductively coupled plasma etching can be used. As wet etching, a method of immersing in dilute hydrochloric acid or dilute sulfuric acid can be used.

Next, the remaining resist layer 61 is removed using a resist removing solution or the like, and the light emitting portion 17 is formed, whereby the organic electroluminescent element 10 can be manufactured (FIG. 10F). The above-described coating method is used for forming the light emitting portion 17. First, an ink in which a light emitting material constituting the light emitting unit 17 is dispersed in a predetermined solvent such as an organic solvent or water is applied. When applying, various methods such as spin coating, spray coating, dip coating, ink jet, slit coating, dispenser, and printing can be used. After the application, the ink is dried by heating or evacuating, and the light emitting material adheres to the inner surface of the recess 16 to form the light emitting portion 17.

Further, after these series of steps, it is preferable to use the organic electroluminescent element 10 stably for a long period of time and to attach a protective layer or a protective cover (not shown) for protecting the organic electroluminescent element 10 from the outside. As the protective layer, polymer compounds, metal oxides, metal fluorides, metal borides, silicon compounds such as silicon nitride and silicon oxide, and the like can be used. And these laminated bodies can also be used. Further, as the protective cover, a glass plate, a plastic plate whose surface has been subjected to low water permeability treatment, a metal, or the like can be used. It is preferable that the protective cover is sealed with a thermosetting resin or a photo-curing resin and bonded to the element substrate. At this time, it is preferable to use a spacer because a predetermined space can be maintained and the organic electroluminescent element 10 can be prevented from being damaged. If an inert gas such as nitrogen or argon is sealed in this space, the cathode layer 15 can be easily prevented from being oxidized. Further, by installing a desiccant such as barium oxide in this space, it becomes easy to suppress the moisture adsorbed in the series of manufacturing steps from damaging the organic electroluminescent element 10.

Next, a display apparatus provided with the organic electroluminescent element detailed above will be described.
FIG. 11 is a diagram illustrating an example of a display device using the organic electroluminescent element in this embodiment.
A display device 200 shown in FIG. 11 is a so-called passive matrix display device, and includes a display device substrate 202, an anode wiring 204, an anode auxiliary wiring 206, a cathode wiring 208, an insulating film 210, a cathode partition wall 212, and an organic electroluminescent element. 214, a counter substrate 216, and a sealing material 218.

As the display device substrate 202, for example, a transparent substrate such as a rectangular glass substrate can be used. The thickness of the display device substrate 202 is not particularly limited, but for example, a thickness of 0.1 mm to 1 mm can be used.

A plurality of anode wirings 204 are formed on the display device substrate 202. The anode wirings 204 are arranged in parallel at a constant interval. The anode wiring 204 is made of a transparent conductive film, and for example, ITO (Indium Tin Oxide) can be used. The thickness of the anode wiring 204 can be set to 100 nm to 150 nm, for example. An anode auxiliary wiring 206 is formed on the end of each anode wiring 204. The anode auxiliary wiring 206 is electrically connected to the anode wiring 204. With this configuration, the anode auxiliary wiring 206 functions as a terminal for connecting to the external wiring on the end portion side of the display device substrate 202, and the anode auxiliary wiring 206 is connected from an external driving circuit (not shown). A current can be supplied to the anode wiring 204 through the wiring. The anode auxiliary wiring 206 is made of a metal film having a thickness of 500 nm to 600 nm, for example.

Further, a plurality of cathode wirings 208 are provided on the display device substrate 202. The plurality of cathode wirings 208 are arranged so as to be parallel to each other and orthogonal to the anode wiring 204. As the cathode wiring 208, Al or an Al alloy can be used. The thickness of the cathode wiring 208 is, for example, 100 nm to 150 nm. Further, similarly to the anode auxiliary wiring 206 for the anode wiring 204, a cathode auxiliary wiring (not shown) is provided at the end of the cathode wiring 208 and is electrically connected to the cathode wiring 208. Therefore, current can flow between the cathode wiring 208 and the cathode auxiliary wiring.

An insulating film 210 is formed on the display device substrate 202 so as to cover the anode wiring 204. The insulating film 210 is provided with a rectangular opening 220 so as to expose a part of the anode wiring 204. The plurality of openings 220 are arranged in a matrix on the anode wiring 204. In the opening 220, an organic electroluminescent element 214 is provided between the anode wiring 204 and the cathode wiring 208 as described later. That is, each opening 220 is a pixel. Accordingly, a display area is formed corresponding to the opening 220. Here, the film thickness of the insulating film 210 can be, for example, 200 nm to 300 nm, and the size of the opening 220 can be, for example, 300 μm × 300 μm.

An organic electroluminescent element 214 is formed at a location corresponding to the position of the opening 220 on the anode wiring 204. Here, in the organic electroluminescent element 214, since the anode wiring 204 replaces the substrate 11, the anode layer 12, the heat dissipation layer 13, the dielectric layer 14, the cathode layer 15, and the light emitting portion are directly formed on the insulating film 210. 17 (see FIG. 1) is formed. The organic electroluminescent element 214 is sandwiched between the anode wiring 204 and the cathode wiring 208 in the opening 220. That is, the anode layer 12 of the organic electroluminescent element 214 is in contact with the anode wiring 204, and the cathode layer 15 is in contact with the cathode wiring 208. The thickness of the organic electroluminescent element 214 can be set to, for example, 150 nm to 200 nm.

A plurality of cathode partitions 212 are formed on the insulating film 210 along a direction perpendicular to the anode wiring 204. The cathode partition 212 plays a role in spatially separating the plurality of cathode wirings 208 so that the wirings of the cathode wirings 208 are not electrically connected to each other. Accordingly, the cathode wiring 208 is disposed between the adjacent cathode partition walls 212. As the size of the cathode partition wall 212, for example, a cathode partition with a height of 2 to 3 μm and a width of 10 μm can be used.

The display device substrate 202 is bonded to the counter substrate 216 via a sealing material 218. Thereby, the space in which the organic electroluminescent element 214 is provided can be sealed, and the organic electroluminescent element 214 can be prevented from being deteriorated by moisture in the air. As the counter substrate 216, for example, a glass substrate having a thickness of 0.7 mm to 1.1 mm can be used.

In the display device 200 having such a structure, a current is supplied to the organic electroluminescent element 214 via the anode auxiliary wiring 206 and the cathode auxiliary wiring (not shown) by a driving device (not shown), the light emitting unit 17 is caused to emit light, and the recess 16 Can emit light. An image can be displayed on the display device 200 by controlling light emission and non-light emission of the organic electroluminescence element 214 corresponding to the above-described pixel by the control device.

Next, a lighting device using the organic electroluminescent element 10 will be described.
FIG. 12 is a diagram illustrating an example of a lighting device including the organic electroluminescent element in the present embodiment.
The lighting device 300 shown in FIG. 12 is installed adjacent to the organic electroluminescent element 10 and the substrate 11 (see FIG. 1) of the organic electroluminescent element 10 and connected to the anode layer 12 (see FIG. 1). A terminal 302, a terminal 303 installed adjacent to the substrate 11 (see FIG. 1) and connected to the cathode layer 15 (see FIG. 1) of the organic electroluminescent element 10, and an organic electric field connected to the

terminals

302 and 303. And a lighting circuit 301 for driving the light emitting element 10.

The lighting circuit 301 has a DC power supply (not shown) and a control circuit (not shown) inside, and supplies a current between the anode layer 12 and the cathode layer 15 of the organic electroluminescent element 10 through the terminal 302 and the terminal 303. And the organic electroluminescent element 10 is driven, the light emission part 17 (refer FIG. 1) is light-emitted, light is radiate | emitted from the recessed part 16, and it uses as illumination light. The light emitting unit 17 may be made of a light emitting material that emits white light, and the organic electroluminescent element 10 using a light emitting material that emits green light (G), blue light (B), and red light (R). A plurality of them may be provided, and the combined light may be white. In the lighting device 300 of the present embodiment, when light is emitted with the diameter and interval of the recesses 16 (see FIG. 1) being reduced, it appears to the human eye to emit light.

Example 1
[Preparation of phosphorescent polymer compound]
A compound represented by the following formula E-2 (iridium complex having a polymerizable substituent), a compound represented by formula E-54 (hole transporting compound), and a compound represented by formula E-66 ( Electron transporting compound) is dissolved in dehydrated toluene at a ratio of E-2: E-54: E-66 = 1: 4: 5 (mass ratio), and V-601 (Wako Pure Chemical Industries, Ltd.) is used as a polymerization initiator. (Made by Corporation) was dissolved. And after performing freeze deaeration operation, it vacuum-sealed and stirred at 70 degreeC for 100 hours, and the polymerization reaction was performed. After the reaction, the reaction solution was dropped into acetone to cause precipitation, and the reprecipitation purification with dehydrated toluene-acetone was repeated three times to purify the phosphorescent polymer compound. Here, as dehydrated toluene and acetone, those obtained by further distilling a high-purity grade manufactured by Wako Pure Chemical Industries, Ltd. were used.
When the solvent after the third reprecipitation purification was analyzed by high performance liquid chromatography, it was confirmed that no substance having absorption at 400 nm or more was detected in the solvent. That is, this means that the solvent contains almost no impurities, which means that the phosphorescent polymer compound has been sufficiently purified. The purified phosphorescent polymer compound was vacuum dried at room temperature for 2 days. As a result, it was confirmed by high performance liquid chromatography (detection wavelength 254 nm) that the phosphorescent polymer compound (ELP) obtained had a purity exceeding 99.9%.

[Preparation of luminescent material solution]
3 parts by weight of the light-emitting polymer compound thus prepared (weight average molecular weight = 52000) was dissolved in 97 parts by weight of toluene to prepare a light-emitting material solution (hereinafter also referred to as “solution A”).

[Production of organic electroluminescence device]
As the organic electroluminescent element, the organic electroluminescent element 80 shown in FIG. 9 was produced by the following method.
Specifically, a sputtering apparatus (E-401s manufactured by Canon Anelva Co., Ltd.) is first formed on a glass substrate (25 mm square, 1 mm thickness) made of quartz glass having a 150 nm thick ITO (Indium Tin Oxide) film on the surface. Were used to form an alumina (Al ₂ O ₃ ) layer of 30 nm and a silicon dioxide (SiO ₂ ) layer of 100 nm. Here, the glass substrate corresponds to the substrate 11. The ITO film corresponds to the anode layer 12, the alumina (Al ₂ O ₃ ) layer corresponds to the heat dissipation layer 13, and the silicon dioxide layer corresponds to the dielectric layer 14.

Next, a photoresist (AZ 1500 made by AZ Electronic Materials Co., Ltd.) was formed to a thickness of about 1 μm by spin coating. After exposure to _{ultraviolet, TMAH (Tetra methyl ammonium hydroxide:} (CH3) 4 NOH) developed with 1.2% solution, the patterned resist layer. Thereafter, heat was applied at 130 ° C. for 10 minutes (post-baking treatment).

Next, the silicon dioxide layer and the alumina (Al ₂ O ₃ ) layer were patterned by dry etching using a reactive ion etching apparatus (RIE-200iP manufactured by Samco Corporation). Here, as etching conditions, CHF ₃ was used as a reaction gas, and the reaction was performed at a pressure of 0.3 Pa and an output Bias / ICP = 60/100 (W) for 16 minutes.

Then, the resist residue was removed with a resist removing solution, and the ITO film was patterned by dry etching using the reactive ion etching apparatus described above. Here, as etching conditions, a mixed gas of Cl ₂ and SiCl ₄ was used as a reaction gas, and the reaction was performed at a pressure of 1 Pa and an output Bias / ICP = 180/100 (W) for 7 minutes. By the two-stage dry etching process described above, the concave portion 16 penetrating the dielectric layer 14, the heat dissipation layer 13, and the anode layer 12 was formed. And this recessed part 16 was a cylindrical shape with a diameter of 2 micrometers (um), and the distance between the edges of the recessed part 16 became 2 micrometers.

Next, the glass substrate was washed by spraying pure water and dried using a spin dryer.

Next, the solution A was applied by a spin coating method (rotation speed: 3000 rpm), and then allowed to stand at 120 ° C. for 1 hour in a nitrogen atmosphere and dried to form the light emitting portion 17.

Then, it was put into a vacuum vapor deposition chamber, and a sodium (Na) film having a thickness of 1.0 nm was formed as a cathode buffer layer on the light emitting unit 17 by a vacuum vapor deposition device. Subsequently, an aluminum (Al) film having a thickness of 150 nm was formed as the cathode layer 15. The organic electroluminescent element 80 was able to be manufactured by the above process.

(Examples 2 to 4)
In contrast to Example 1, the alumina (Al ₂ O ₃ ) layer, which is the heat dissipation layer 13, was changed to 50 nm (Example 2), 200 nm (Example 3), and 250 nm (Example 4). A light emitting device 80 was manufactured.

(Examples 5 to 6)
In contrast to Example 1, an AlN (aluminum nitride) layer (Example 5) and a Ti (titanium) layer (Example 6) were formed as the heat dissipation layer 13 and the film thickness was set to 50 nm. An organic electroluminescent element 80 was produced.

(Example 7)
As the organic electroluminescent element, the organic electroluminescent element 10d shown in FIG. 2D was produced by the following method.
Specifically, first, on a silicon substrate (25 mm square, 1 mm thickness) having an ITO (Indium Tin Oxide) film having a thickness of 150 nm on the surface, a sputtering apparatus (E-401s manufactured by Canon Anelva Co., Ltd.) was used. An alumina (Al ₂ O ₃ ) layer was deposited to 100 nm, a silicon dioxide (SiO ₂ ) layer was deposited to 50 nm, and an aluminum (Al) layer was deposited to 100 nm. Here, the silicon substrate corresponds to the substrate 11. The ITO film corresponds to the anode layer 12, the alumina (Al ₂ O ₃ ) layer corresponds to the heat dissipation layer 13, the silicon dioxide layer corresponds to the dielectric layer 14, and the aluminum layer corresponds to the cathode layer 15.

Next, a photoresist (AZ1500 manufactured by AZ Electronic Materials Co., Ltd.) was formed to a thickness of about 1 μm by spin coating. After exposure with ultraviolet rays, the resist layer was patterned by developing with a 1.2% solution of TMAH (Tetra methyl ammonium hydroxide: (CH3) 4NOH). Thereafter, heat was applied at 130 ° C. for 10 minutes (post-baking treatment).

Next, the aluminum layer, the silicon dioxide layer and the alumina layer were patterned by dry etching using a reactive ion etching apparatus (RIE-200iP manufactured by Samco Corporation). Here, as etching conditions, CHF3 was used as a reaction gas, and the reaction was performed at a pressure of 0.3 Pa and an output Bias / ICP = 60/100 (W) for 20 minutes.

Subsequently, the ITO film was patterned using the reactive ion etching apparatus. A mixed gas of Cl ₂ and SiCl ₄ was used as a reaction gas, and the reaction was performed at a pressure of 1 Pa and an output Bias / ICP = 180/100 (W) for 7 minutes.
Then, the resist residue was removed with a resist removing solution.
By the two-stage dry etching process described above, the concave portion 16 penetrating the cathode layer 15, the dielectric layer 14, the heat dissipation layer 13, and the anode layer 12 was formed. And this recessed part 16 was a cylindrical shape with a diameter of 2.5 micrometers (um), and the distance between the edges of the recessed part 16 became 1.5 micrometers.

Next, the solution A was applied by a spin coating method (rotation speed: 3000 rpm), and then allowed to stand at 120 ° C. for 1 hour in a nitrogen atmosphere and dried to form the light emitting portion 17. The organic electroluminescent element 10d was able to be manufactured through the above steps.

(Example 8)
As the organic electroluminescent element, the organic electroluminescent element 30 shown in FIG. 4 was produced by the following method.
Specifically, an alumina (Al ₂ O ₃ ) layer is formed on a glass substrate (25 mm square, 1 mm thickness) made of soda glass by using a sputtering apparatus (E-401s manufactured by Canon Anelva Co., Ltd.) with a thickness of 50 nm. The film was 150 nm, the silicon dioxide (SiO ₂ ) layer was 100 nm, the alumina (Al ₂ O ₃ ) layer was 50 nm, the aluminum (Al) layer was 150 nm, and the alumina (Al ₂ O ₃ ) layer was 50 nm in this order. Here, the glass substrate corresponds to the substrate 11. The alumina (Al ₂ O ₃ ) layer corresponds to the heat dissipation layer 13, the ITO film corresponds to the anode layer 12, the silicon dioxide layer corresponds to the dielectric layer 14, and the aluminum layer corresponds to the cathode 15.

Next, a photoresist (AZ 1500 made by AZ Electronic Materials Co., Ltd.) was formed to a thickness of about 1 μm by spin coating. After exposure with ultraviolet rays, the resist layer was patterned by developing with a 1.2% solution of TMAH (Tetra methyl ammonium hydroxide: (CH ₃ ) ₄ NOH). Thereafter, heat was applied at 130 ° C. for 10 minutes (post-baking treatment).

Next, an alumina (Al ₂ O ₃ ) layer, an aluminum layer, and a silicon dioxide layer were patterned by dry etching using a reactive ion etching apparatus (RIE-200iP manufactured by Samco Corporation). Here, as etching conditions, CHF ₃ was used as a reaction gas, and the reaction was performed at a pressure of 0.3 Pa and an output Bias / ICP = 60/100 (W) for 19 minutes.

Subsequently, the ITO film was patterned using the reactive ion etching apparatus. Here, as etching conditions, a mixed gas of Cl ₂ and SiCl ₄ was used as a reaction gas, and the reaction was performed at a pressure of 1 Pa and an output Bias / ICP = 180/100 (W) for 7 minutes.
Furthermore, the alumina (Al ₂ O ₃ ) layer was patterned using the reactive ion etching apparatus. Here, as etching conditions, CHF ₃ was used as a reaction gas, and the reaction was performed at a pressure of 0.2 Pa and an output Bias / ICP = 60/100 (W) for 5 minutes.

Then, the resist residue was removed with a resist removing solution. Through the above three-stage dry etching process, the cathode 15, the dielectric layer 14, the heat dissipation layer 13, the anode layer 12, and the recess 16 penetrating the heat dissipation layer 13 were formed. And this recessed part 16 was a cylindrical shape with a diameter of 3 micrometers (um), and the distance between the edges of the recessed part 16 became 1 micrometer.

Next, the solution A was applied by a spin coating method (rotation speed: 3000 rpm), and then allowed to stand at 120 ° C. for 1 hour in a nitrogen atmosphere and dried to form the light emitting portion 17. The organic electroluminescent element 30 was able to be manufactured by the above process.

(Comparative Example 1)
An organic electroluminescent element was produced in the same manner as in Example 1 except that the alumina (Al ₂ O ₃ ) layer as the heat dissipation layer 13 was not formed.

(Comparative Example 2)
In Example 7, instead of forming an alumina (Al ₂ O ₃ ) layer of 100 nm and a silicon dioxide (SiO ₂ ) layer of 50 nm, a silicon dioxide layer of 150 nm was formed. That is, the organic electroluminescent element was produced without forming the heat dissipation layer 13.

[Evaluation of organic electroluminescence device]
For each of the organic electroluminescent devices prepared in Examples 1 to 8 and Comparative Examples 1 and 2, the luminance unevenness and the power efficiency were evaluated by the following methods.

(Evaluation of uneven brightness)
(1) There is a correlation between the light emission intensity of the organic electroluminescent element and the temperature of the organic electroluminescent element in a state where a constant voltage is applied. That is, a temperature distribution is generated in the light emitting surface of the organic electroluminescent element, thereby causing a luminance distribution (luminance unevenness) on the light emitting surface.
(2) From this fact, the brightness distribution immediately after energization of the organic electroluminescent element (temperature is uniform in the plane) after lighting for a certain period of time (temperature has reached a steady state, depending on the magnitude of the heat dissipation effect) The change in luminance distribution (which produces an in-plane temperature distribution) was used as an index indicating the magnitude of the temperature distribution.
(3) As a specific measurement method, the luminance distribution is an organic electroluminescence device having a light emitting surface of 5 mm □, and the light emitting surface is divided into three equal parts vertically and horizontally, and the numerical value is a ratio between the luminance at the center and the luminance at the four corners. Turned into. Each measurement area was circular with a diameter of approximately 0.5 mm. Here, a luminance meter (Topcon Co., Ltd., BM-9, viewing angle 0.2 degree) was used for the luminance. The luminance immediately after energization was measured within 5 seconds after the start of energization of the organic electroluminescent element. Further, the luminance after lighting for a certain time was measured 3 minutes after lighting.
(4) Calculate the ratio of the central luminance and the luminance at the four corners immediately after energization, the ratio between the central luminance and the luminance at the four corners after lighting for a certain period of time, and further divide the latter ratio by the former ratio. This was used as an index of the degree of luminance unevenness due to the heat rise of the organic electroluminescent element. That is, in a normal organic electroluminescent device, the ratio of the central luminance immediately after energization to the luminance at the four corners (center / corner) is approximately 1, but when the temperature is stored by lighting, the temperature of the central portion is larger than the corner temperature. It becomes temperature. Therefore, after lighting for a certain time, the luminance at the center> the luminance at the corner. At this time, if the ratio of the luminance at the center to the luminance at the four corners (center / corner) is 1.4, for example, 1.4 / 1 = 1.4 is luminance unevenness due to the heat rise of the organic electroluminescent element. It can be used as an index of the degree. Usually, this value is larger than 1, and a value closer to 1 is preferable because the temperature distribution in the light emitting surface is small and luminance unevenness is small. In addition, that this numerical value is 1 means that the temperature in the light emission surface of an organic electroluminescent element is uniform.

(Evaluation of power efficiency)
When the luminous efficiency of the organic electroluminescent device is lowered, a large amount of electric power is required to realize a certain luminance. Since part of the input power becomes heat, the greater the input power, the greater the amount of heat generated, resulting in a larger temperature distribution. In the organic electroluminescence device, when the structure is changed by providing a heat dissipation layer or the like, the light emission efficiency is lowered, and as a result, the heat generation amount is increased. Since the heat dissipation becomes better as the heat dissipation layer becomes thicker, it is possible to suppress the temperature distribution from occurring at a certain thickness. However, if the thickness exceeds the certain thickness, the heat generation is superior and the temperature distribution tends to occur.
Therefore, a constant voltage was applied to the organic electroluminescent element, and the power efficiency, which is a numerical value obtained by dividing the luminance by the power (= voltage × current) flowing at this time, was considered, and this was used as an index of the luminous efficiency.
The results are shown in Table 1 below. The power efficiency is normalized and displayed with Example 1 as 1.

As can be seen from Table 1, the brightness unevenness is improved in each of Examples 1 to 8 as compared to Comparative Examples 1 and 2. That is, by providing the heat dissipation layer 13, the temperature distribution is made uniform and luminance unevenness is suppressed. Further, when Examples 1 to 4 are compared, the power efficiency tends to decrease as the alumina film thickness increases. From Table 1, it can be seen that the film thickness of the heat dissipation layer 13 is preferably about 50 nm to 200 nm when the luminance unevenness and the power efficiency values of Examples 1 to 4 are compared.
Further, when Examples 2, 5 and 6 in which the material constituting the heat radiation layer 13 is changed and the film thickness is 50 nm are compared, alumina having a high thermal conductivity (thermal conductivity 29 W / (m · K)), AlN ( 130 W / (m · K)) and Ti (240 W / (m · K)) are suppressed in luminance unevenness, and it can be seen that there is a heat dissipation effect.
Furthermore, it can be seen that even in the case where the layer configuration of the organic electroluminescent element is changed as in Examples 7 and 8, the formation of the heat dissipation layer 13 suppresses unevenness in luminance and has a heat dissipation effect.

It is sectional drawing explaining the 1st example of the organic electroluminescent element to which this Embodiment is applied. It is a figure explaining the other form of the shape of the light emission part. It is sectional drawing explaining the 2nd example of the organic electroluminescent element to which this Embodiment is applied. It is sectional drawing explaining the 3rd example of the organic electroluminescent element to which this Embodiment is applied. It is sectional drawing explaining the 4th example of the organic electroluminescent element to which embodiment is applied. It is sectional drawing explaining the 5th example of the organic electroluminescent element to which this Embodiment is applied. It is sectional drawing explaining the 6th example of the organic electroluminescent element to which this Embodiment is applied. It is sectional drawing explaining the 7th example of the organic electroluminescent element to which this Embodiment is applied. It is sectional drawing explaining the 8th example of the organic electroluminescent element to which this Embodiment is applied. It is a figure explaining the manufacturing method of the organic electroluminescent element to which this Embodiment is applied. It is a figure explaining an example of a display apparatus provided with the organic electroluminescent element in this Embodiment. It is a figure explaining an example of an illuminating device provided with the organic electroluminescent element in this Embodiment.

DESCRIPTION OF

SYMBOLS

10, 20, 30, 40, 50, 60, 70, 80 ... Organic electroluminescent element, 11 ... Board | substrate, 12 ... Anode layer, 13 ... Radiation layer, 14 ... Dielectric layer, 15 ... Cathode layer, 16 ... Recessed part, 17 ... Light-emitting part, 18 ... 2nd recessed part, 200 ... Display apparatus, 300 ... Illumination device

Claims

A first electrode layer;
A second electrode layer;
A dielectric layer formed between the first electrode layer and the second electrode layer;
A recess formed through at least the dielectric layer;
A light emitting part formed in contact with the inner surface of the recess;
A heat dissipating layer for dissipating heat generated from the light emitting part,
An organic electroluminescent device comprising:
The organic electroluminescence device according to claim 1, wherein the heat dissipation layer is formed between the first electrode layer and the second electrode layer.
3. The organic electroluminescence device according to claim 2, wherein the heat dissipation layer has a thickness of 50 nm to 200 nm.
The organic electroluminescence device according to claim 1, wherein the heat dissipation layer is formed in contact with at least one of the first electrode layer and the second electrode layer.
5. The organic electroluminescent device according to claim 4, wherein the heat dissipation layer has a thickness of 0.2 μm to 1000 μm.
The organic electroluminescence device according to any one of claims 1 to 5, wherein the heat dissipation layer is formed in accordance with the shape of the recess.
The heat dissipation layer includes at least one selected from aluminum nitride, tantalum nitride, alumina, sapphire, beryllium oxide, magnesium oxide, diamond-like carbon, single crystal silicon, polycrystalline silicon, amorphous silicon, silicon carbide, and a metal material. The organic electroluminescent element according to claim 1, wherein:
The organic electroluminescence device according to any one of claims 1 to 7, wherein the heat dissipation layer has a thermal conductivity of 10 W / (m · K) or more.
The said recessed part is a substantially cylindrical shape which penetrates the said 1st electrode layer, the said 2nd electrode layer, the said dielectric material layer, and the said heat dissipation layer, The any one of Claim 1 thru | or 8 characterized by the above-mentioned. The organic electroluminescent element as described.
9. The concave portion according to claim 1, wherein the concave portion has a groove shape that penetrates the first electrode layer, the second electrode layer, the dielectric layer, and the heat dissipation layer and is substantially parallel to each other. 2. The organic electroluminescent element according to item 1.
The organic electroluminescent element according to any one of claims 1 to 10, wherein the recess further penetrates at least one of the first electrode layer and the second electrode layer.
The organic electroluminescent element according to any one of claims 1 to 11, wherein the light emitting part includes a phosphorescent light emitting material.
13. The organic electroluminescent device according to claim 12, wherein the phosphorescent material is a phosphorescent polymer having a molecular weight of 1,000 to 2,000,000 in terms of weight average molecular weight.
14. The organic electroluminescent element according to claim 12, wherein the phosphorescent material comprises a phosphorescent unit that emits phosphorescence and a carrier transport unit that transports carriers in one molecule.
The organic electroluminescent element according to any one of claims 1 to 14, wherein the first electrode layer and the second electrode layer are made of an opaque material.
A display device comprising the organic electroluminescent element according to any one of claims 1 to 15.
A lighting device comprising the organic electroluminescent element according to any one of claims 1 to 15.