WO2006093176A1

WO2006093176A1 - Organic electroluminescent device, image display and illuminating device

Info

Publication number: WO2006093176A1
Application number: PCT/JP2006/303837
Authority: WO
Inventors: Aki Nakata; Tomoyuki Nakayama
Original assignee: Konica Minolta Holdings, Inc.
Priority date: 2005-03-04
Filing date: 2006-03-01
Publication date: 2006-09-08
Also published as: JP4946862B2; JPWO2006093176A1

Abstract

Disclosed is an organic electroluminescent device which enables to achieve high luminous efficiency at low driving voltage while having high productivity. Also disclosed are an image display and an illuminating device each comprising such an organic electroluminescent device. Specifically disclosed is an organic electroluminescent device comprising at least an anode, a cathode and an organic layer, which is arranged between the anode and the cathode and includes a light-emitting unit, on a supporting substrate. The light-emitting unit has two or more light-emitting layers having different emission peaks, and all the light-emitting layers contain a light-emitting dopant and a light-emitting host. When the total film thickness of the organic layers between the anode and the light-emitting unit is represented by d1, the film thickness of the light-emitting unit is represented by d2, and the total film thickness of the organic layers between the light-emitting unit and the cathode is represented by d3, the organic electroluminescent device is characterized by satisfying 5 nm ≤ d2 ≤ 30 nm and 5 ≤ (d1 + d3)/d2.

Description

ORGANIC ELECTRIC ELECTROLUMINES ELEMENT, IMAGE DISPLAY DEVICE AND LIGHTING DEVICE TECHNICAL FIELD

TECHNICAL FIELD [0001] The present invention relates to an organic electoluminescence device, an image display device including the organic electroluminescence device, and an illumination device.

Background art

[0002] Since organic EL elements are self-luminous, they have excellent visibility and can be driven at a low voltage of several volts to several tens of volts, so that light weight including a drive circuit is possible. Therefore, organic EL devices are expected to be used as thin film displays, lighting, and knock lights.

[0003] Organic EL elements are also characterized by abundant color nomination. Another characteristic is that various colors can be emitted by combining colors.

[0004] Among luminescent colors, the need for white light emission is particularly high, and it can also be used as a backlight for displays. Furthermore, it can be divided into blue, green and red pixels using a color filter.

[0005] There are the following two methods for performing such white light emission.

[0006] 1. One light emitting layer is doped with a plurality of light emitting compounds.

[0007] 2. A plurality of emission colors are combined from a plurality of emission layers.

[0008] For example, when white is achieved by three colors of blue (B), green (G), and red (R), in the case of 1, the vacuum deposition method is used as a device manufacturing method, and BGR It becomes quaternary deposition of the luminescent host compound, which makes it very difficult to control. In addition, there is a method in which BGR and a light-emitting host compound are dissolved or dispersed in a solution, but at present, there is a problem that the coating type organic EL is inferior in durability to the vapor deposition type.

[0009] On the other hand, a method of combining a plurality of two light emitting layers has been proposed. When using the evaporation type, it becomes easier than 1.

[0010] Such an organic EL element that emits white light is formed by stacking two layers of a blue light-emitting layer that emits short wavelength light and a yellow light-emitting layer that emits long wavelength light. Proposals have been made to obtain color emission (for example, see Patent Document 1). O

However, in the case where two light emitting layers having different color development (different peak wavelengths) are stacked, the driving time of the element, that is, the light emission time and the applied voltage are changed as 2 There was a problem that the emission center moved due to changes in film quality in the two light-emitting layers and changes in the transportability of holes and electrons, and as a result, chromaticity was likely to change.

[0012] In particular, when white is obtained as a mixed color of two light emitting layers, since white is more sensitive to chromaticity changes than other colors, a problem becomes apparent.

[0013] In addition, a high-efficiency organic electoluminescence element can be obtained by using an ortho metal complex as a light-emitting material, and as a method for obtaining white light, there is a method of obtaining white color by stacking three colors of BGR. (For example, refer to Patent Document 2.) ₀

[0014] In addition, in an organic EL element that emits mixed color light having a plurality of light emitting layer strengths having different peak wavelengths, there is a difference as a method for minimizing chromaticity change due to drive time or voltage change. those in which the light-emitting layer is laminated alternately three or more layers has been disclosed for emitting light having a peak wavelength (for example, see Patent Document 3.) ₀

[0015] By the way, a white light emitting element that achieves white color by combining a plurality of light emitting layers has a structure in which a number of light emitting layers are stacked, so that the thickness of the light emitting layer is increased, and the number of interfaces between layers is also increased. There is a problem that carrier injection is hindered and the drive voltage is increased. In particular, when a phosphorescent material was used, there was a problem that the driving voltage was higher than that of a fluorescent material.

[0016] The drive voltage can be lowered by making the light emitting layer thinner, but by reducing the overall film thickness, the device is more susceptible to the effects of minute dust on the substrate and the performance of the device is not stable. There was a problem that the sex became worse.

Patent Document 1: Japanese Patent Laid-Open No. 2003-347051

Patent Document 2: Japanese Patent Laid-Open No. 2001-319780

Patent Document 3: JP 2004-63349 A

Disclosure of the invention

Problems to be solved by the invention [0017] The present invention has been made in view of the above problems, and an object of the present invention is to provide an organic electoluminescence element having high luminous efficiency and low productivity at a low driving voltage, and the organic electoduct. An object of the present invention is to provide an image display device and a lighting device having a luminescence element.

Means for solving the problem

[0018] The above object of the present invention has been achieved by the following constitution.

[0019] 1. In an organic electoluminescence device having at least an anode, a cathode, and an organic layer including a light emitting unit between the anode and the cathode on a supporting substrate, the light emitting unit includes two light emitting layers having different emission peaks. Each of the light emitting layers contains a light emitting dopant and a light emitting host,

When the total film thickness of the organic layer between the anode and the light emitting unit is dl, the film thickness of the light emitting unit is d2, and the total film thickness of the organic layer between the light emitting unit and the cathode is d3, each film An organic electroreductive element characterized in that the relationship between the thicknesses d1, d2, and d3 satisfies both of the following formulas (1) and (2).

[0020] Formula (1)

5nm≤d2 <30nm

Formula (2)

5≤ (dl + d3) / d2

2. The organic electroluminescence device according to 1 above, wherein the relationship between the film thicknesses dl, d2, and d3 satisfies the following formula (3).

[0021] Formula (3)

dl + d2 + d3> 150nm

3. The light-emitting unit is composed of at least two light-emitting layers having different light emission peaks, and at least two adjacent light-emitting layers of the light-emitting unit contain the same light-emitting host compound. 2. The organic electoluminescence device according to 2.

[0022] 4. The light-emitting unit is characterized in that the light-emitting unit is composed of at least two light-emitting layers having different emission peaks, and all the light-emitting layers of the light-emitting unit contain the same light-emitting host compound. Or The organic electoluminescence device according to 2. [0023] 5. The organic electroluminescent element as described in 3 or 4 above, wherein the junction part of two adjacent light emitting layers of the light emitting unit has a mixed region of two kinds of light emitting dopants. .

[0024] 6. All the light-emitting layer forces of the light-emitting unit each include two or more light-emitting dopants, and the concentration of the light-emitting dopant varies continuously in the light-emitting unit. 5. The organic electoluminescence device according to any one of 5 above.

[0025] 7. The organic electroluminescent device according to 1 or 2 above, wherein an intermediate layer not containing a light emitting dopant is provided between light emitting layers having different light emission peaks of the light emitting unit.

[0026] 8. The organic electrification as described in 7 above, wherein the intermediate layer contains a light-emitting host compound, and at least two adjacent layers of the light-emitting unit contain the same light-emitting host compound. Tronoreminence element.

[0027] 9. The organic electroluminescence according to 7 above, wherein the intermediate layer contains a light-emitting host compound, and all the layers of the light-emitting unit contain the same light-emitting host compound. element.

[0028] 10. In any one of 1 to 9 above, wherein the dl is a range defined by the following formula (4) and the d3 is a range defined by the following formula (5): The organic elect mouth luminescence element of description.

[0029] Formula (4)

120nm≤dl≤180nm

Formula (5)

30nm≤d3≤80nm

11. Of the light emitting layers having different light emission peaks, the thickness of the light emitting layer having the light emission peak at the shortest wavelength is d4, and d2 and d4 satisfy the following formula (6): The organic electoluminescence device according to any one of 1 to 10 above.

[0030] Formula (6)

d2 / d4 <2

12. The light emitting power of the organic electoluminescence device is white. The organic electoluminescence device according to any one of 1 to 11 above.

[0031] 13. In any one of the above 1 to 12, wherein the light emitting dopant contained in at least one light emitting layer among the light emitting layers having different emission peaks is a phosphorescent compound. The organic-elect mouth luminescence element of description.

[0032] 14. In any one of the above 1 to 12, wherein the light emitting dopant contained in at least two light emitting layers among the light emitting layers having different emission peaks is a phosphorescent compound. The organic-elect mouth luminescence element of description.

[0033] 15. The organic electoluminescence device according to any one of 1 to 12, wherein the light-emitting dopant contained in all light-emitting layers having different emission peaks is a phosphorescent compound.

[0034] 16. The organic-electric-luminescence device according to any one of 1 to 15 above is used.

An image display device characterized by the fact that V

[0035] 17. An illuminating device using the organic-electric-luminescence element according to any one of 1 to 15 above.

The invention's effect

[0036] According to the configuration of the present invention, there are provided an organic electroluminescent device having high luminous efficiency at a low driving voltage and high productivity, and an image display device and an illuminating device having the organic electroluminescent device. I was able to.

Brief Description of Drawings

FIG. 1 is a diagram showing an example of a basic layer configuration of the present invention.

FIG. 2 is a schematic view showing an example of a vapor deposition apparatus having a plurality of light emitting host compounds and a plurality of light emitting dopant deposition boats.

FIG. 3 is a diagram showing a light-emitting unit having a mixed region of two types of light-emitting dopants at a joint portion between two adjacent light-emitting layers in Example 3.

FIG. 4 is a view showing a light emitting unit in which all layers of the light emitting unit in Example 4 each contain two or more types of light emitting dopants, and the content ratio is continuously changed.

FIG. 5 is a schematic view showing an example of a display device constituted by an organic EL element cover.

FIG. 6 is a schematic diagram of a display unit. FIG. 7 is a schematic diagram of a pixel.

FIG. 8 is a schematic view showing an example of a passive matrix type full-color display device. Explanation of symbols

[0038] 1 display

3 pixels

5 scan lines

6 Data line

7 Power line

10 Organic EL devices

11 Switching transistor

12 Ma District Motion Transistor

13 Capacitor

21 Shutter

22 Deposition boat

23 Support substrate

A Display section

B Control unit

BEST MODE FOR CARRYING OUT THE INVENTION

[0039] The organic electoluminescence device of the present invention (hereinafter also referred to as an organic EL device) has at least an anode, a cathode, and an organic layer including a light emitting unit between the anode and the cathode on a supporting substrate, The unit has two or more light-emitting layers having different light emission peaks, all of the light-emitting layers contain a light-emitting dopant and a light-emitting host, the total thickness of the organic layer between the anode and the light-emitting unit is dl, and the light-emitting unit Is d2 and the total thickness of the organic layer between the light emitting unit and the cathode is d3, the thickness (d2) of the light emitting unit is 5 nm or more and less than 30 nm, preferably 7 to 27 nm. The most preferable range is 10 to 25 nm.

[0040] Further, it is one of the characteristics that the thickness (dl + d3) of the organic layer excluding the light emitting unit is five times or more the film thickness (d2) of the light emitting unit. [0041] With this configuration, an organic electoluminescence device with a low driving voltage and high productivity can be realized while being a white light emitting device in which a plurality of light emitting layers are combined. Further, by using a phosphorescent material as the light emitting dopant, higher efficiency could be achieved.

[0042] The layer structure of the organic electroluminescence device (organic EL device) of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

The device configuration shown in FIG. 1 has a light emitting unit between a cathode and an anode, and the light emitting unit is sandwiched between an electron blocking layer and a hole blocking layer.

[0044] In the present invention, the light emitting unit means from the light emitting layer located closest to the cathode side to the light emitting layer located closest to the anode side of the organic electoluminescence device (for example, in FIG. 1, the light emitting layer 2 and the light emitting layer 3 become a light emitting unit).

[0045] These electron blocking layers or hole blocking layers are not necessarily required. However, by adopting such a configuration, electron and hole carriers are confined in the light emitting unit, and further, by recombination of electrons and holes. Since these excitons can also be confined in the light emitting unit, it is preferable to provide these layers.

A known material can be used as a material for forming the electron blocking layer and the hole blocking layer.

[0047] Since the electron blocking layer confines electrons so that electrons do not leak from the light emitting unit, the material forming the electron blocking layer is preferably smaller in electron affinity than the material forming the light emitting unit.

[0048] Further, since the hole blocking layer confines holes so that holes do not leak from the light emitting unit, the material forming the hole blocking layer has an ionization potential higher than the material forming the light emitting unit. Big! /, I like it! / ...

[0049] Further, in order to confine triplet excitons generated by recombination of electrons and holes, the material forming the hole blocking layer and the electron blocking layer is an excited triplet of the phosphorescent compound of the light emitting unit. It ’s bigger than energy!

Furthermore, it is preferable to provide a hole transport layer and an electron transport layer so as to sandwich them.

For the hole transport layer and the electron transport layer, known materials can be used, and it is preferable to use a material having high conductivity from the viewpoint of lowering driving voltage.

[0051] In the present invention, the light emitting unit emits light of at least two layers having different emission peaks. It is composed of layers, preferably 2 or 3 layers.

[0052] All the light emitting layers of the light emitting unit contain a light emitting host and a light emitting dopant.

[0053] In the present invention, it is preferable that two adjacent light emitting layers of the light emitting unit are composed of the same light emitting host compound, and that all the light emitting layers are composed of the same light emitting host compound. preferable. By using the same light emitting host compound in the light emitting layer, the adhesion between the layers is improved, the carrier injection barrier between different layers is relaxed, and the driving voltage can be lowered. The same effect can be obtained when a mixed region is provided between the two light emitting layers, or when the concentration of the light emitting dopant is continuously changed in the light emitting unit.

In the present invention, a light emitting layer having a different emission peak means that the emission maximum wavelength differs by at least lOnm or more when the emission peak is measured by PL.

[0055] In PL measurement, a vapor deposition film is formed on a quartz substrate with a composition using a light-emitting dopant and a light-emitting host compound in a light-emitting layer, or a wet process such as a polymer is used for spin measurement. The light emission maximum wavelength can be determined by preparing a thin film by coating or dipping and measuring the luminescence of the obtained deposited film or thin film with a fluorometer.

[0056] In the present invention, the light emitting unit includes two or more light emitting layers having different light emission peaks. Between the light emitting layer and the light emitting layer, a non-light emitting intermediate layer ( Emission dopants are not included! / Both intermediate layers! /, U) are provided! / I also like that! / By providing the intermediate layer, it becomes easier to control the injection of carriers into the light emitting layer, and color shift can be prevented.

[0057] A known material can be used as the material of the intermediate layer. However, the intermediate layer contains the same luminescent host compound as the luminescent host compound contained in the adjacent luminescent layer. Is improved and the carrier injection barrier between different layers is relaxed. More preferably, since all the layers of the light emitting unit (light emitting layer and intermediate layer) contain the same host compound, the adhesion between the layers is further improved and the carrier injection barrier between different layers is increased. It is further relaxed.

[0058] The color when the organic EL of the present invention is lit is not particularly limited, but is preferably white.

[0059] For example, when two light emitting layers having different light emission peaks are used, it is preferable to obtain a white color by combining the light emitting layers that emit blue and yellow, blue and orange, or blue green and red. [0060] For example, there are three types of light emitting layers with different light emission peaks, and the light emitting layer is composed of three light emitting layers.

It is preferable to obtain white by combining blue, green and red.

[0061] With such a configuration, it can be used for various light sources such as illumination and backlight.

[0062] The emission color is not limited to white.

[0063] By making a single color (for example, blue, green, red) emit light with a plurality of light emitting layers having different light emission peaks, it is possible to perform finer color adjustment.

In the present invention, it is preferable that the layer thickness dl of the organic layer between the anode and the light emitting layer and the layer thickness d3 of the organic layer between the light emitting layer and the cathode satisfy the following ranges.

[0065] 120nm≤dl≤180nm, powerful 30nm≤d3≤80nm, more preferably ί, 130nm≤dl

≤170nm and 40nm≤d3≤70nm.

[0066] By satisfying the conditions specified above, it is possible to optically enhance blue light emission, which has lower light emission efficiency than other colors, and to increase the light emission efficiency of the white element.

[0067] In the present invention, for the same reason as described above, among the light emitting layers having different light emission peaks,

When the thickness of the light emitting layer having the emission peak at the shortest wavelength is d4, it is preferable that d2 and d4 satisfy the following formula.

[0068] d2 / d4 <2, and more preferably d2 / d4 <l.5.

[0069] (Luminescent Host Compound and Luminescent Dopant)

The mixing ratio of the light-emitting dopant to the light-emitting host compound as the main component in the light-emitting layer is preferably in the range of 0.1% by mass to less than 30% by mass.

[0070] However, in the present invention, it is preferable to use a phosphorescent compound (phosphorescent dopant) as the light-emitting dopant of at least one layer of the light-emitting layer. It is best to use a phosphorescent compound as the light-emitting dopant for all light-emitting layers where it is more preferable to use a compound. The light emitting dopant may be a metal complex or a phosphorescent dopant having another structure, which may be used by mixing a plurality of kinds of compounds.

[0071] The light-emitting dopant is roughly classified into two types: a fluorescent dopant that emits fluorescence and a phosphorescent dopant that emits phosphorescence. [0072] Representative examples of fluorescent dopants include coumarin dyes, pyran dyes, cyanine dyes, chromochrome dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes. Examples thereof include dyes, pyrylium dyes, perylene dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

[0073] As a typical example of the phosphorescent dopant, preferably a complex compound containing a metal of Group 8, Group 9, or Group 10 in the periodic table of elements, more preferably an iridium compound or an osmium compound, Of these, iridium compounds are the most preferred.

[0074] Specific examples of the phosphorescent dopant are compounds described in the following patent publications.

[0075] International Publication No. OOZ70655 Pamphlet K JP 2002-280178 A, JP 2001

— No. 181616, No. 2002-280179, No. 2001-181617, No. 2002-280180, No. 2001-247859, No. 2002-299060, No. 2001-313178 JP, JP 2002-302671, JP 2001-345183, JP 2002-324679, WO 02,15645 Pamphlet, JP 2002-332291, JP 2002-50484 No., JP 2002-33 2292, JP 2002-83684, JP 2002-540572, JP 20 02-117978, JP 2002-338588, JP 2002-170684 No., JP 2002-352960 A, WO 01/93642 pamphlet, JP 2002

— 50483, JP 2002-100476, JP 2002-173674, JP 2002-359082, JP 2002-175884, JP 2002-363552, JP 2002-184582 Publication, JP 2003-7469, JP 2002-525 808, JP 2003-7471, JP 2002-525833, JP 2003

— 31366, JP 2002-226495, JP 2002-234894, JP 2002-235076, JP 2002-241751, JP 2001-319779, JP 2001-319780 JP, 2002-62824, JP 2002-10474, JP 2002-203679, JP 2002-343572, JP 2002-203678, and the like.

[0076] Some of the specific examples are shown below. The present invention is not limited to these.

L £ 8 £ 0 £ / 900ZdT / 13d

Tsuyoshi [6 00]

L £ 8 £ 0 £ / 900ZdT / 13d 9.TC60 / 900Z OAV

[0080] (Luminescent Host Compound)

The luminescent host compound used in the present invention is a compound having a phosphorescence quantum yield of phosphorescence of less than 0.01 at room temperature (25 ° C.).

[0081] The luminescent host compound used in the present invention is not particularly limited in terms of structure, but representatively, a power rubazole derivative, a triarylamine derivative, an aromatic borane derivative, a nitrogen-containing complex. A ring compound, a thiophene derivative, a furan derivative, an oligoarylene compound or the like having a basic skeleton, or a carboline derivative or diaza force rubazole derivative (Here, diaza force rubazole derivative is a carboline ring of a carboline derivative. Configure The hydrocarbon ring is one in which at least one carbon atom is substituted with a nitrogen atom. ) Etc. are mentioned.

Of these, carboline derivatives, diaza force rubazole derivatives and the like are preferably used.

[0083] Specific examples of carboline derivatives, diaza force rubazole derivatives, force rubazole derivatives and the like are given below, but the present invention is not limited thereto.

[0084] [Chemical 4]

[0085] [Chemical 5] H-12 H-13

[0086] The light-emitting host compound used in the present invention may be a low-molecular compound or a high-molecular compound having a repeating unit, and may be a low-molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerization light emission). May be a host compound).

[0087] As the light-emitting host compound, a compound having a hole transporting ability and an electron transporting ability, which prevents emission light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable.

[0088] As specific examples of the light-emitting host compound, compounds described in the following documents are suitable. For example, JP-A-2001-257076, 2002-308855, 200

1-313179, 2002-319491, 2001-357977, 2

002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002 2002-105445, 2002-343568, 2002-141173, 2002-352957, 2002-203683, 2002-363227, 2002-231453, 2003 — Publication No. 3165, Publication No. 2002-234888, Publication No. 2003-27048, Publication No. 2002-255934, Publication No. 2002-260861, Publication No. 2002-280183, Publication No. 2002-299060, Publication No. 2002 — 302516 Publication, 2002-305083 Publication, 2002-305084 Publication, 2002-308837 Publication, etc.

Next, other constituent layers that can be used in the organic EL device of the present invention will be described.

[0090] << Hole blocking layer >>

In a broad sense, the hole blocking layer has the function of an electron transport layer, which is a material force that has the function of transporting electrons while transporting holes and is extremely small, and blocks holes while transporting electrons. By doing so, the probability of recombination of electrons and holes can be improved.

[0091] Examples of the hole blocking layer include, for example, Japanese Patent Application Laid-Open Nos. 11204258 and 11204359, and “The Forefront of Organic EL Devices and Their Industrialization (November 30, 1998, NTT Corporation) The hole blocking (hole blocking) layer described in page 237 of “Issuance”) is applicable as the hole blocking layer according to the present invention. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer based on this invention as needed.

[0092] << Electron blocking layer >>

On the other hand, the electron blocking layer has the function of a hole transport layer in a broad sense, and is a material force that has a function of transporting holes and an extremely small capacity of transporting electrons, and transports holes while transporting holes. The probability of recombination of electrons and holes can be improved by blocking the children. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed.

[0093] The thickness of the hole blocking layer and the electron blocking layer according to the present invention is preferably 3ηπ! ˜lOOnm, more preferably 5 nm to 30 nm.

[0094] << Hole Transport Layer >>

The hole transport layer includes a material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers. [0095] As a hole transport material, there is no particular limitation. Conventionally, in a photoconductive material, it is commonly used as a hole charge injection / transport material and used for a hole injection layer or a hole transport layer of an EL element. Any one of known ones used can be selected and used.

[0096] The hole transport material has a hole injection or transport, electron barrier property! /, Or a deviation, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives , Stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

[0097] As a hole transporting material, the above-mentioned forces that can be used are preferably porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds, particularly aromatic tertiary amine compounds. ,.

[0098] Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-1,4'-daminophenol; N, N' —Diphenyl N, N '— Bis (3-methylphenol) 1 [1, 1' — Biphenyl] 1, 4, 4 '— Diamine (TPD); 2, 2 Bis (4 di-p-tolylaminophenol 1, 1-bis (4 di-l-tri-laminophenol) cyclohexane; N, N, N ', N'—tetra-l-tolyl-1,4,4'-diaminobiphenyl; 1 Bis (4 di-p-triaminophenol) 4 Phenol mouth hexane; Bis (4-dimethylamino 2-methylphenol) phenylmethane; Bis (4-di-p-triaminophenol) phenol; N, N ' —Diphenyl N, N '—Di (4-methoxyphenyl) 4, 4'diaminobiphenyl; N, N, N ', N' — Tetraphenyl —4, 4 'Diaminodiphenyl -Luether; 4, 4 'Bis (diphenylamino) quadryl; N, N, N Tri (p tolyl) amine; 4— (Di-p-tolylamino) — 4 ′ — [4— (Di — p-tolylamino) styryl] stilbene; 4-N, N diphenylamino- (2 diphenyl) benzene; 3-methoxy 1'-N, N diphenylaminostilbenzene; N phenolcarbazole, and more US Pat. No. 5,061,569 having two condensed aromatic rings in the molecule, for example, 4, 4 ′ bis [N- (1-na (Futil) N-Feramino] Bi-Fowl (NPD), three triphenylamine units described in JP-A-4 308688 are connected in a starburst type 4, 4 ', A "—Tris [? ^ — (3-methylphenol) N phenolamine] triphenylamine (MTD ATA) and the like.

[0099] Further, a polymer material in which these materials are introduced into a polymer chain or these materials as a polymer main chain can also be used.

[0100] Inorganic compounds such as p-type Si and p-type SiC can also be used as a hole injection material and a hole transport material. Further, the hole transport material preferably has a high Tg.

[0101] The hole transport layer is formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, an ink jet method, or an LB method. be able to. The thickness of the hole transport layer is not particularly limited, but is usually 5ηπ! ~ 50 OOnm or so. This hole transport layer may have a single-layer structure in which one or more of the above materials are used.

[0102] An impurity-doped hole transport layer with high p property can also be used. Examples thereof include those described in JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, R. Ap pi. Phys., 95, 5773 (2004), etc. It is done.

[0103] 《Electron Transport Layer》

The electron transport layer is a material force having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be a single layer or a plurality of layers.

Conventionally, in the case of a single electron transport layer and a plurality of layers, as an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side, The materials listed are known.

[0105] Furthermore, the electron transport layer may be any material selected from conventionally known compounds as long as it has a function of transmitting electrons injected from the cathode to the light emitting layer. It is possible to be.

[0106] Examples of materials used for this electron transport layer (hereinafter referred to as electron transport materials) include: -substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide oxide derivatives, Examples include heterocyclic tetracarboxylic anhydrides such as phthaleneperylene, carbodiimide, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, and oxadiazole derivatives. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, or a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material.

Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

[0108] In addition, metal complexes of 8 quinolinol derivatives such as tris (8 quinolinol) aluminum (Alq), tris (5,7-dichloro-1-8-quinolinol) aluminum, tris (5,7-jib mouth)

Three

Mo-quinolinol) aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metal of these metal complexes is In, Metal complexes replacing Mg, Cu, Ca, Sn, Ga or Pb can also be used as electron transport materials. In addition, metal free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. In addition, the distyrylvirazine derivative exemplified as the material for the light emitting layer can also be used as an electron transport material, and, like the hole injection layer and the hole transport layer, n-type-Si, n-type-SiC, etc. These inorganic semiconductors can also be used as electron transport materials.

[0109] The electron transport layer may be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, an ink jet method, or an LB method. it can. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, it is about 5-5000 nm. This electron transport layer may have a single-layer structure having one or more of the above materials.

[0110] Further, an n-type electron transport layer doped with impurities can be used. Examples thereof include those described in JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, R. Ap pi. Phys., 95, 5773 (2004), etc. It is done.

[0111] << Injection layer >>: Electron injection layer, hole injection layer The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer. As described above, the injection layer exists between the anode and the light emitting layer or hole transport layer, and between the cathode and the light emitting layer or electron transport layer. May be present.

[0112] The injection layer is a layer provided between the electrode and the organic layer in order to reduce the drive voltage and improve the luminance of the light emission. “The organic EL element and its industrial front line (November 30, 1998) Chapter 2 “Electrode materials” (pages 123-166) of “Part 2” of “Tees Co., Ltd.”) describes the details of the hole injection layer (anode buffer layer) and the electron injection layer (cathode buffer). One layer).

[0113] The details of the anode buffer layer (hole injection layer) are also described in JP-A-9-45479, JP-A-9260062, JP-A-8-288069 and the like. A phthalocyanine buffer layer typified by phthalocyanine, an oxide buffer layer typified by vanadium oxide, an amorphous carbon buffer layer, a polymer buffer layer using a conductive polymer such as polyarene (emeraldine) or polythiophene Etc.

[0114] The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. A metal buffer layer typified by aluminum or aluminum, an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, or an acid aluminum salt A single acid buffer.

[0115] The buffer layer (injection layer) preferably has a very thin film thickness, but the film thickness is preferably in the range of 0.1 nm to 100 nm.

[0116] This injection layer can be formed by thin-filming the above material by a known method such as a vacuum deposition method, a spin coating method, a casting method, an ink jet method, or an LB method. The thickness of the injection layer is not particularly limited, but is usually about 5 to 5000 nm. This injection layer may have a single-layer structure in which one or more of the above materials are used.

[0117] Anode

As the anode according to the organic EL device of the present invention, an electrode material made of a metal, an alloy, an electrically conductive compound or a mixture thereof having a high work function (4 eV or more) is preferably used. It is done. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as Cul, indium tin oxide (ITO), SnO, and ZnO. IDIXO (In O-

2 2 3

An amorphous material such as ZnO) that can produce a transparent conductive film may be used. For the anode, these electrode materials can be formed into a thin film by vapor deposition or sputtering, and a pattern with a desired shape can be formed by a single photolithography method. m or more), a pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. In the case of extracting light emission from this anode, it is desirable to have a transmittance of more than 10%, and the sheet resistance as the anode is preferably several hundred Ω or less. Furthermore, the film thickness depends on the material. Usually ΙΟηπ! ˜1000 nm, preferably 10 nm to 200 nm.

[0118] 《Cathode》

On the other hand, as the cathode according to the present invention, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof is used. Specific examples of such electrode materials include sodium, sodium-powered rhodium alloy, magnesium, lithium, magnesium Z copper mixture, magnesium Z silver mixture, magnesium / aluminum mixture, magnesium Z indium mixture, aluminum Z acid aluminum (Al 2 O 3) mixture, indium, lithium

2 3 Z aluminum mixture, rare earth metals, etc. Among these, in terms of electron injectability and durability against oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function value than this, for example, a magnesium Z silver mixture, Magnesium Z Aluminum Mixture, Magnesium Z Indium Mixture, Aluminum Z Acid-Aluminum (Al 2 O 3) Mixture

twenty three

Lithium Z aluminum mixture, aluminum and the like are preferred. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω or less. The film thickness is usually selected in the range of 10 nm to 1000 nm, preferably 50 nm to 200 nm. In order to transmit light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, it is convenient to improve the light emission luminance.

[0119] << Substrate (also referred to as substrate, substrate, support, etc.) >> The substrate of the organic EL device of the present invention is not particularly limited in the type of glass, plastic and the like, and is not particularly limited as long as it is transparent. Examples of the substrate preferably used include glass, Examples thereof include quartz and a light-transmitting resin film. Especially preferred, the substrate is a resin film that can give flexibility to organic EL elements

[0120] Examples of the resin film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylenesulfide, polyarylate, polyimide, polycarbonate (PC). , Cellulose triacetate (TAC), cellulose acetate propionate (CAP) and the like.

[0121] On the surface of the resin film, an inorganic film or an organic film, or a hybrid film of both of them may be formed, and the water vapor transmission rate is 0.01 gZm ² 'dayatm or less. I prefer to be there.

[0122] The external extraction efficiency at room temperature of light emission of the organic electoluminescence device of the present invention is preferably 1% or more, more preferably 2% or more. Here, external extraction quantum efficiency (%) = number of photons emitted outside the organic EL element Z number of electrons flowing through the organic EL element X 100.

[0123] When used for illumination, a roughened film (such as an antiglare film) can be used in combination in order to reduce unevenness in light emission.

[0124] << Method for Fabricating Organic EL Element >>

As an example of a method for producing the organic EL device of the present invention, an anode / hole injection layer / hole transport layer

Z light emitting layer (two or more layers) Z hole blocking layer Z electron transport layer Z cathode buffer layer A method for producing an organic EL device comprising a Z cathode will be described.

[0125] First, on a suitable substrate, a desired electrode material, for example, a thin film having a material force for an anode, is 1 μm or less, preferably ΙΟηπ! An anode is formed by a method such as vapor deposition or sputtering so as to have a film thickness of ˜200 nm. Next, a thin film containing an organic compound such as a hole injection layer, a hole transport layer, a light emitting layer (two or more layers), a hole blocking layer, and an electron transport layer, which are element materials, is formed thereon. [0126] As a method of forming a thin film containing this organic compound, there are a spin coat method, a cast method, an ink jet method, a vapor deposition method, a printing method, and the like. A homogeneous film can be obtained immediately and a pinhole is generated. From the viewpoint of shiniku! /, Etc., vacuum deposition or spin coating is particularly preferred. Further, a different film forming method may be applied for each layer.

[0127] Film in the case of employing an evaporation method, the deposition conditions may vary due to kinds of materials used, generally boat temperature 50 ° C~450 ° C, vacuum degree of 10- ⁶ Pa~10- ² Pa, deposition rate 0.01 nm to 50 nm Z seconds, substrate temperature -50. C ~ 300. C, film thickness of 0.1 ηπι to 5; ζ πι is preferably selected as appropriate.

A vapor deposition apparatus that can be used in the method for forming an organic EL element of the present invention is shown in FIG.

FIG. 2 is a schematic diagram of a vapor deposition apparatus having a plurality of vapor deposition boats for a plurality of light emitting host compounds and a plurality of light emission dopants. By controlling the heating temperature of each boat and the opening / closing of the shutter associated with each boat, a light emitting unit having light emitting layers with different light emission peaks can be formed.

[0130] In the vapor deposition apparatus, an intermediate layer boat is provided, and an intermediate layer that does not include a light emitting dopant is provided between two adjacent light emitting layers of the light emitting unit. It is preferable because of its prevention effect.

[0131] Further, by using the above evaporation apparatus, all of the light emitting layers having different emission peaks contain a light emitting dopant and a light emitting host compound, and two adjacent light emitting layers are made of the same light emitting host compound. In addition, all of the light emitting layers having different emission peaks can be composed of the same light emitting host compound, and two kinds of each of the light emitting units at the junction of two adjacent light emitting layers can be formed. It is necessary to have a mixed region of light emitting dopants, and to have an inclined mixed region in which all the layers of the light emitting unit contain two or more kinds of light emitting dopants and the content ratio gradually changes. For example, it is possible to obtain a configuration for various purposes, and to obtain the effect of lowering the driving voltage.

[0132] After the formation of these layers, a thin film having a cathode material force is formed thereon by a method such as vapor deposition or sputtering so that the film thickness is 1 μm or less, preferably in the range of 50 nm to 200 nm. By forming and providing a cathode, a desired organic EL device can be obtained. The organic EL device is manufactured from the hole injection layer to the cathode in a single vacuum. Although it is preferable, even if it is taken out in the middle and subjected to a different film forming method, it does not matter. At that time, it is necessary to consider that the work is performed in a dry inert gas atmosphere.

[0133] <Display device>

The display device of the present invention will be described.

[0134] The image display apparatus using the organic EL element of the present invention may be monochromatic or multicolored. In the case of a multicolor display device, a shadow mask is provided for each color light-emitting unit, and three or more light-emitting layers are formed for each color by vapor deposition, casting, spin coating, ink-jet method, printing method, or the like.

[0135] When patterning is performed on the light emitting unit, the method is not limited, but a vapor deposition method, an inkjet method, and a printing method are preferable. When using the vapor deposition method, patterning using a shadow mask is preferred.

[0136] In the case of a single color, for example, white, the vapor deposition method or the casting method is performed on one side without patterning.

Two or more light emitting layers are formed by a spin coating method, an ink jet method, a printing method, or the like.

[0137] In addition, it is also possible to reverse the production order to produce a cathode, an electron transport layer, a hole blocking layer, a light emitting layer (two or more layers), a hole transport layer, and an anode in this order.

[0138] When a DC voltage is applied to the image display device thus obtained, the anode is

When a voltage of about 2 to 40 V is applied with the negative polarity of the cathode, light emission can be observed. In addition, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Furthermore, when an AC voltage is applied, light is emitted only when the anode is + and the cathode is in the same state. The AC waveform to be applied is arbitrary.

[0139] In the case of a white display device, it can be used as a display device, a display, or various light emission sources. In display devices and displays, the use of white organic EL elements as backlights enables full color display.

[0140] Display devices and displays include televisions, personal computers, mono equipment, AV equipment, text broadcast displays, information displays in automobiles, and the like. It can be used especially as a display device for playing back still images and moving images.

[0141] Light emitting sources include household lighting, interior lighting, clock and liquid crystal backlights, signboard advertisements, traffic lights, light sources of optical storage media, light sources of electrophotographic copying machines, light sources of optical communication processors, Examples include, but are not limited to, a light source of an optical sensor.

[0142] 《Lighting device》

The lighting device of the present invention will be described.

[0143] The organic EL device having a resonator structure may be used as an organic EL device having a resonator structure in the organic EL device of the present invention. Examples include, but are not limited to, photocopier light sources, optical communication processor light sources, and optical sensor light sources.

[0144] Further, the organic EL device of the present invention may be used as a kind of lamp such as an illumination or exposure light source, a projection device of a type for projecting an image, a still image or a moving image. It may be used as a display device (display) of the type that is directly visually recognized. When used as a display device for video playback, either the simple matrix (passive matrix) method or the active matrix method may be used. Alternatively, a full color display device can be produced by using two or more organic EL elements of the present invention having different emission colors.

[0145] When the organic EL device of the present invention is used as a white light emitting device, full color display can be performed in combination with a color filter of BGR.

The organic EL element of the present invention can also be applied to an organic EL element that emits substantially white light as a lighting device.

[0147] Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.

FIG. 5 is a schematic diagram showing an example of a display device configured with organic EL element power. FIG. 2 is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.

The display 1 also includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, and the like.

[0150] The control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of a plurality of pixels based on image information from the outside. Sequentially emits light according to the image data signal, scans the image, and displays image information on display A. To display.

FIG. 6 is a schematic diagram of the display unit A.

[0152] The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below.

FIG. 6 shows a case where the light intensity emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

[0154] The scanning line 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at orthogonal positions ( Details are not shown).

[0155] When the scanning signal is applied from the scanning line 5, the pixel 3 receives the image data signal from the data line 6, and emits light according to the received image data. Full color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region on the same substrate.

[0156] When the organic EL device of the present invention is used as a white light emitting device, full color display can be performed by combination with a BGR color filter.

Next, the light emission process of the pixel will be described.

FIG. 7 is a schematic diagram of a pixel.

The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. A full-color display can be performed by using an organic EL element that emits white light as the organic EL element 10 divided into multiple pixels and combining it with a BGR color filter.

In FIG. 7, an image data signal is also applied to the drain of the switching transistor 11 via the data line 6 in the control unit B force. When a scanning signal is applied to the gate of the switching transistor 11 via the control unit B force scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is transferred to the capacitor 13 and the driving transistor. It is transmitted to the gate of the star 12.

With the transmission of the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the drive of the drive transistor 12 is turned on. The drive transistor 12 has a drain IN is connected to the power line 7 and the source is connected to the electrode of the organic EL element 10, and current is supplied from the power line 7 to the organic EL element 10 according to the potential of the image data signal applied to the gate. Is done.

[0162] When the scanning signal is moved to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off. However, even if the driving of the switching transistor 11 is turned off, the capacitor 13 holds the potential of the charged image data signal, so that the driving of the driving transistor 12 is kept on and the next scanning signal is applied. The organic EL device 10 continues to emit light until it is seen. When a scanning signal is next applied by sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.

[0163] That is, the organic EL element 10 emits light by providing a switching transistor 11 and a drive transistor 12 as active elements for each of the plurality of pixels. Element 10 is emitting light. Such a light emitting method is called an active matrix method.

Here, light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or a predetermined light emission amount by a binary image data signal. On, even a talent! /.

[0165] Further, the potential of the capacitor 13 may be maintained until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.

In the present invention, not only the active matrix method described above, but also a passive matrix light emission drive in which the organic EL element emits light according to the data signal only when the scanning signal is scanned.

[0167] FIG. 8 is a schematic diagram of a display device using a passive matrix method. A plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a grid pattern so as to face each other with the pixel 3 interposed therebetween.

When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixel 3 connected to the applied scanning line 5 emits light according to the image data signal. With the noisy matrix method, pixel 3 has no active elements, and manufacturing costs can be reduced.

[0169] In the white organic EL device of the present invention, a metal mask and an in- You may also use the jet printing method for patterning. When patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned.

As described above, the white light emitting organic EL element of the present invention is not only the display device and the display, but also various light sources and lighting devices such as home lighting, interior lighting, and exposure light source. As a lamp, it is also useful for a display device such as a backlight of a liquid crystal display device.

[0171] Other light sources such as backlights for watches, billboard advertisements, traffic lights, optical storage media, electronic photocopiers, light sources for optical communication processors, light sources for optical sensors, and display devices are also required. And a wide range of uses such as general household appliances.

Example

[0172] Example 1

<< Production of organic EL elements >>

The ITO transparent electrode was provided after patterning was performed on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 110 nm of ITO (indium oxide) on a glass substrate of 100 mm X 100 mm X I. 1 mm as the anode. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus. On the other hand, 200 mg of copper phthalocyanine (CuPc) is put in a molybdenum resistance heating boat, 200 mg of α-NPD is put in another resistance heating boat made of molybdenum, and 20 mg of m-TDATA is put in another resistance heating boat made of molybdenum. Put another 200 mg H-14 in a resistance heating boat made of molybdenum, put 200 mg H-15 in another resistance heating boat made in molybdenum, put lOOmg Ir 12 in another resistance heating boat made of molybdenum, put another resistance in molybdenum Ir—15 mg of Ir-15 was placed in a heating boat, 200 mg of H—16 was placed in another molybdenum resistance heating boat, and 200 mg of Alq was placed in another resistance heating boat made of molybdenum, and attached to a vacuum evaporation system.

Three

[0173] Next, in, after pressure in the vacuum tank was reduced to 4 X 10- ⁴ Pa, heated by passing electricity to the heating boat containing CuPc, of deposited onto the transparent substrate at a depositing speed 0. InmZsec 20nm Hole injection A layer was provided.

[0174] Further, the heating boat containing ex-NPD was energized and heated, and deposited on the hole injection layer at a deposition rate of 0.1 nm / s ec to provide a 1 OOnm hole transport layer.

[0175] Further, the heating boat containing m—TDATA was energized and heated to a deposition rate of 0.1 nm.

A 15 nm electron blocking layer was deposited on the hole transport layer at / sec.

[0176] Further, the heating boat containing H-14 and Ir-12 was energized and heated, and co-evaporated on the hole transport layer with the mass ratio and film thickness shown in Table 1 to emit yellow light. The light emitting layer 1 was provided.

[0177] Further, the heating boat containing H-15 and Ir-15 was energized and heated, and co-evaporated on the light emitting layer 1 with the mass ratio and film thickness shown in Table 1 to emit blue light. The light emitting layer 2 was provided.

[0178] Further, the heating boat containing H-16 was energized and heated, and deposited on the light emitting layer at a deposition rate of 0.1 nm / sec to provide a hole blocking layer having a thickness of lOnm.

[0179] Further, the heating boat containing Alq was energized and heated, and the deposition rate was 0. InmZsec.

Three

An electron transport layer having a thickness of 40 nm was provided by vapor deposition on the light emitting layer.

[0180] The substrate temperature during vapor deposition was room temperature.

[0181] Subsequently, 0.5 nm of lithium fluoride was vapor-deposited as a cathode buffer layer, and further, aluminum 1 lOnm was vapor-deposited to form a cathode, whereby an organic EL device 1-1 was produced.

[0182] <Production of organic EL element 1 2>

The ITO transparent electrode was provided after patterning on a substrate (NH Techno Glass NA45) made of 1 lOnm of ITO (indium oxide) on a 100 mm X 100 mm XI. 1 mm glass substrate as an anode. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. A poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PED OTZPSS, manufactured by Bayer, Baytron P Al 4083) dispersion was formed on this transparent support substrate by spin coating at 3000 rpm for 30 seconds. Then, it was dried at 200 ° C for 1 hour, and an 80 nm hole injection layer was provided. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus. On the other hand, 200 mg of α NPD is put into a molybdenum resistance heating boat, 200 mg of m-TDATA is put into another molybdenum resistance heating boat, and 200 mg of H-14 is put into another molybdenum resistance heating boat. Put 200 mg of H-15 in a resistance heating boat made of molybdenum, Ir-12 is put into a Ribden resistance heating boat, lOOmg Ir 15 is put into another molybdenum resistance heating boat, 200 mg H-16 is put into another molybdenum resistance heating boat, and another molybdenum resistance is added. Put 200mg of Alq into a heated boat and use it as a vacuum evaporation system.

Three

Installed.

[0183] Next, in, after pressure in the vacuum tank was reduced to 4 X 10- ⁴ Pa, and heated by supplying an electric current to the boat containing a-NPD, on the hole injection layer at a deposition rate of 0. InmZsec A 40nm hole transport layer was provided by vapor deposition.

[0184] Further, the heating boat containing m—TDATA was energized and heated to a deposition rate of 0.1 nm.

[0185] Further, the heating boat containing H-14 and Ir-12 was energized and heated, and co-evaporated on the hole transport layer with the mass ratio and film thickness shown in Table 1 to emit yellow light. The light emitting layer 1 was provided.

[0186] Further, the heating boat containing H-15 and Ir-15 was energized and heated, and co-evaporated on the light-emitting layer 1 with the mass ratio and film thickness shown in Table 1 to emit blue light. The light emitting layer 2 was provided.

[0187] Further, the heating boat containing H-16 was energized and heated, and deposited on the light-emitting layer 2 at a deposition rate of 0. Inm / sec to provide a hole blocking layer having a thickness of lOnm.

[0188] Further, the heating boat containing Alq was energized and heated, and the deposition rate was 0. InmZsec.

Three

An electron transport layer having a thickness of 40 nm was formed by vapor deposition on the hole blocking layer.

[0189] The substrate temperature during vapor deposition was room temperature.

Subsequently, 0.5 nm of lithium fluoride was vapor-deposited as a cathode buffer layer, and further, aluminum 1 lOnm was vapor-deposited to form a cathode, whereby an organic EL device 1-2 was produced.

[0191] <Preparation of organic EL devices 1-3, 1-4, 16-18>

OLED devices 1-3, 1-4, and 1-6 to 1-8 were prepared in the same manner as the organic EL devices 1-2, except that the light emitting layer was changed to the configuration shown in Table 1. did.

[0192] <Organic EL device 1 5>

Organic EL element 1-5 was prepared in the same manner as in the manufacture of organic EL element 1-1, except that the light emitting layer was changed to the structure shown in Table 1.

[0193] <Production of organic EL devices 1-9 to 1-11: Comparative example>

In the production of the organic EL device 1-1, a hole injection layer, a hole transport layer, and a light emitting layer were formed. Organic EL elements 19 to 111 were fabricated in the same manner except that the configuration was changed as shown in Table 1.

[0194] The mass% display in the light emitting layer 1 and the light emitting layer 2 in Table 1 will be described.

[0195] For example, in the organic EL element 11 of Table 1, the material of the light-emitting layer 1 is a force described as H-14: Ir 12 (3 mass%, 20 nm). Among them, H-14 represents 97 mass%, Ir-12 represents 3 mass%, and the light-emitting layer 1 has a thickness of 20 nm.

[0196] This display is the same for the other white light emitting organic electoluminescence elements 11 to 112.

[0197] << Evaluation >>

Each obtained element was evaluated by the following method.

[0198] (Measurement of external extraction quantum efficiency, power efficiency, dark spot generation rate)

With respect to the produced organic EL device, the external extraction quantum efficiency (%) was measured when a constant current of ^2.5 mA / cm ² was applied in a dry nitrogen gas atmosphere at 23 ° C. For the measurement, a spectral radiance meter CS-1000 (manufactured by Co-Camino Norta Sensing) was used. In addition, power efficiency (lm (lumen) ZW) was measured as an indicator of lower drive voltage and power consumption. In addition, as a measure of productivity and device performance stability, the dark spot generation rate (the force that dark spots are generated in 10 devices) was measured, and the results obtained are shown in Table 2.

[0199] The measurement results of external extraction quantum efficiency and power efficiency shown in Table 2 were expressed as relative values when the measured value of the organic EL elements 1-12 was set to 100.

[0200] The compounds used for forming each layer are shown below.

[0201] [Chemical 6]

[0202] [Table 1]

Power efficiency dark spot

Organic EL device External extraction quantum efficiency tree Remarks

(1 m / W) Incidence rate

1-1 162 230 0 The present invention

1 1 2 167 240 0 Invention t-3 1 10 1 50 0 Invention 卜 4 152 220 0 Invention

1 1 5 150 210 0 The present invention

1 -6 155 223 0 The present invention

1-7 161 232 0 The present invention

1 1 8 160 220 0 Present invention

1 -9 100 200 5 Comparative example 卜 10 140 70 0 Comparative example 卜 1 1 22 53 2 Comparative example

1-1 2 TOO 100 1 Comparative example

[0204] It can be seen that the sample of the present invention does not generate dark spots with high luminous efficiency, has stable device performance, and high production efficiency.

[0205] Example 2

In the production of the organic EL elements 1-1 to 1-8 described in Example 1, the organic EL element 2 was similarly prepared except that H-16 was provided as an intermediate layer between the respective light emitting layers by a 2 nm deposition method. — :! ~ 2— Organic EL device manufactured in Example 1 and manufactured in Example 1 1— :! The following evaluation of chromaticity deviation was conducted together with ~ 1-8, and the results obtained are shown in Table 3.

[0206] <Evaluation of chromaticity shift>

The chromaticity shift is shown in the CIE chromaticity diagram! /, And the chromaticity coordinate at lOOcdZm ² luminance and the chromaticity coordinate at 5000 cdZ m ² luminance. The measurement was performed using CS-100 (manufactured by Corminor Minolta Sensing) at 23 ° C in a dry nitrogen gas atmosphere.

[0207] [Table 3]

Organic EL element number Organic EL element number

(No intermediate layer) Chromaticity deviation Chromaticity deviation

(With middle class)

1 1 1 0.030 2 1 1 0.008

1 1 2 0.050 2-2 0 .010

1 1 3 0.042 2-3 0 .009

1 1 4 0.037 2-4 0 .008

1 1 5 0.020 2-5 0 .002

1-6 0.025 2-6 0.004

1-7 0.031 2-7 0.007

1-8 0.027 0 .005

[0208] As can be seen from the results shown in Table 3, organic EL elements 2-1 to 2-8 are organic EL elements 1

Compared with 1-18, it can be seen that the chromaticity shift at high voltage is suppressed.

[0209] Example 3

When the organic EL device 1-8 described in Example 1 was manufactured, as shown in FIG. 3, H-16 and Ir-13 were formed between the light emitting layer 1 and the light emitting layer 2 in the light emitting unit. In the same manner, except that a mixed region 2 of H-16, Ir-1, and Ir-9 is provided 2 nm between the mixed region 1 of Ir-1 and the light emitting layer 2 and the light emitting layer 3, respectively. — 8 was made. However, in the mixed region 1, the deposition rate of Ir-1 is increased by increasing the deposition starting force so that the deposition rate of Ir-13 also decreases the deposition starting force and becomes 0 when the film thickness reaches 2 nm. When the thickness reached 2 nm, the mass ratio with H-16 was adjusted to be the same as that of the light emitting layer 2. In the mixed region 2 as well, the deposition rate of Ir-1 is decreased from the start of deposition and becomes 0 when the thickness reaches 2 nm, and the deposition rate of Ir 9 is increased from the start of deposition to 2 nm. At that time, the mass ratio with H-16 was adjusted to be the same as that of the light emitting layer 3.

[0210] <Measurement of power efficiency>

The power efficiency (lm (lumen) / W) was measured for the fabricated organic EL device when a constant current of 2.5 mAZcm ² was applied at 23 ° C in a dry nitrogen gas atmosphere. Show. For the measurement, a spectral radiance meter CS-1000 (manufactured by Co-Camino Norta Sensing) was used in the same manner.

[0211] The power efficiency measurement results shown in Table 4 were expressed as relative values when the measured value of the organic EL element 18 was 100. [0212] [Table 4]

[0213] As is clear from the results shown in Table 4, it was confirmed that the drive voltage of the organic EL element 3-8 was lower than that of the organic EL element 1-8.

[0214] Example 4

The production of the organic EL device 18 described in Example 1 was the same except that the concentration of the light emitting dopant was continuously changed in the light emitting unit in all layers of the light emitting unit as shown in FIG. Thus, organic EL elements 4-8 were produced.

[0215] However, the light emitting unit of Fig. 4 was manufactured as follows.

[0216] H-16, Ir13, Ir1, Ir9 were simultaneously energized and heated to adjust the deposition rate and start vacuum deposition. When the thickness of the light emitting unit is Onm, the deposition is started so that the mass ratio becomes H—16: Ir—13: Ir—1: 1 r—9 = 96.8: 3: 0.1: 0.1. With the speed kept constant, the mass ratio reached 94.9: 2: 3: 0. 1 when the film thickness reached 18 nm, and the mass ratio reached 91.9: 0.1: 3: 5 when the film thickness reached 22 nm. When the film thickness reached 25 nm, the deposition rate was adjusted to 11: -13, 11: 1, 11: -9 so that the mass ratio would be 90.8: 0.1: 0.1: 9

[0217] <Measurement of power efficiency>

The power efficiency (lm (lumen) / W) was measured for the fabricated organic EL device when 2.5 mAZcm ² constant current was applied at 23 ° C in a dry nitrogen gas atmosphere. The results are shown in Table 5. . For the measurement, a spectral radiance meter CS-1000 (manufactured by Ko-Force Minolta Sensing Co., Ltd.) was used in the same manner.

[0218] The power efficiency measurement results shown in Table 5 are expressed as relative values when the measured value of the organic EL elements 1-8 is 100.

[0219] [Table 5] Organic EL device

Power efficiency

1-8 100

4-8 158

[0220] As is clear from the results shown in Table 5, it was confirmed that the driving voltage of the organic EL element 4-8 was lower than that of the organic EL element 1-8.

[0221] Example 5

In the production of the organic EL devices 1-1-1-8 described in Example 1, the hole injection layer and the hole transport layer were changed to m-MTDATA: F4-TCNQ (mass ratio 99: 1) co-deposited film. Alq B

Three

Phen: Cs (mass ratio 75: 25) Organic EL devices 5-1 to 5-8 were fabricated in the same manner except that it was changed to a co-deposited film and LiF was not deposited.

[0222] [Chemical 7]

BPhen F4-TCNQ

[0223] It was confirmed that the organic EL elements 5-1 to 5-8 had a driving voltage 3 to 6 V lower than the organic EL elements 11 to 18.

[0224] Example 6

When the organic EL element 17 described in Example 1 was manufactured, the non-light emitting surface was covered with a glass case, and a color filter was attached to the light emitting surface to use it as an image display device. And was able to be used as an excellent image display device.

[0225] Example 7

In the production of the organic EL device 12 described in Example 1, the non-light emitting surface was covered with a glass case. It was covered and used as a lighting device. The lighting device could be used as a thin lighting device that emits white light with high luminous efficiency.

Claims

The scope of the claims

[1] In an organic electoluminescence device having an organic layer including at least an anode, a cathode, and a light emitting unit between the anode and the cathode on a support substrate, the light emitting unit includes two or more light emitting layers having different light emission peaks. Each of the light emitting layers contains a light emitting dopant and a light emitting host,

Formula (1)

5nm≤d2 <30nm

Formula (2)

5≤ (dl + d3) / d2

[2] The organic electroluminescence device according to claim 1, wherein the relationship between the film thicknesses dl, d2, and d3 satisfies the following formula (3).

Formula (3)

dl + d2 + d3> 150nm

[3] The light emitting unit is composed of at least two light emitting layers having different light emission peaks, and at least two adjacent light emitting layers of the light emitting unit contain the same light emitting host compound. The organic electoluminescence device according to item 1 or 2.

[4] The light emitting unit is composed of at least two light emitting layers having different light emission peaks, and all the light emitting layers of the light emitting unit contain the same light emitting host compound. Or the organic electoluminescence device of a 2nd term | claim.

[5] The organic material according to claim 3 or 4, wherein each of the joining portions of the two adjacent light emitting layers of the light emitting unit has a mixed region of two kinds of light emitting dopants. Electroreminescence element.

[6] All light emitting layer forces of the light emitting unit each contain two or more light emitting dopants, 6. The organic electroluminescent device according to claim 3, wherein the concentration of the light-emitting dopant continuously changes in the light-emitting unit.

[7] The organic according to claim 1 or 2, wherein an intermediate layer not containing a light-emitting dopant is provided between the light-emitting layers having different emission peaks of the light-emitting unit. Elect mouth luminescence element.

[8] The organic elect according to claim 7, wherein the intermediate layer contains a luminescent host compound, and at least two adjacent layers of the luminescent unit contain the same luminescent host compound. Mouth luminescence element.

9. The organic electroluminescent device according to claim 7, wherein the intermediate layer contains a luminescent host compound, and all the layers of the luminescent unit contain the same luminescent host compound. .

[10] Any one of claims 1 to 9, wherein the dl is a range defined by the following formula (4) and the d3 is a range defined by the following formula (5): Force Organic luminescence device according to item 1.

Formula (4)

120nm≤dl≤180nm

Formula (5)

30nm≤d3≤80nm

[11] Of the light emitting layers having different emission peaks, the thickness of the light emitting layer having the emission peak at the shortest wavelength is d4, and d2 and d4 satisfy the following formula (6): The organic electroluminescence device according to any one of items 1 to 10 in the scope of claims to be made.

Formula (6)

d2 / d4 <2

[12] The organic electroluminescence device according to any one of [1] to [11], wherein the organic electroluminescence device has a white light emitting power from the organic electroluminescence device.

[13] The light-emitting dopant contained in at least one light-emitting layer among the light-emitting layers having different emission peaks is a phosphorescent compound. Nominal force Organic luminescence device according to item 1.

[14] The light-emitting dopant contained in at least two light-emitting layers among the light-emitting layers having different emission peaks is a phosphorescent compound. Nominal force Organic luminescence device according to item 1.

[15] The power of any one of [1] to [12], wherein the light emitting dopant contained in all the light emitting layers having different light emission peaks is a phosphorescent compound. Organic luminescence element.

[16] An image display device using the organic electoluminescence element according to any one of [1] to [15].

[17] An illuminating device using the organic-electric-luminescence element according to any one of [1] to [15].