CN102201543B - Organic electric-field light-emitting element and use its organic electric field luminescent display - Google Patents
Organic electric-field light-emitting element and use its organic electric field luminescent display Download PDFInfo
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- CN102201543B CN102201543B CN201110078456.6A CN201110078456A CN102201543B CN 102201543 B CN102201543 B CN 102201543B CN 201110078456 A CN201110078456 A CN 201110078456A CN 102201543 B CN102201543 B CN 102201543B
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
- H10K50/80—Constructional details
- H10K50/85—Arrangements for extracting light from the devices
- H10K50/852—Arrangements for extracting light from the devices comprising a resonant cavity structure, e.g. Bragg reflector pair
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
- H10K59/30—Devices specially adapted for multicolour light emission
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
- H10K59/30—Devices specially adapted for multicolour light emission
- H10K59/35—Devices specially adapted for multicolour light emission comprising red-green-blue [RGB] subpixels
Abstract
The invention provides a kind of organic electric-field light-emitting element, it is the organic electric-field light-emitting element at least successively with the first electrode, luminescent layer, the second semi-transmissive electrode, intermediate layer, semitransmissive layer and light-transmitting layer, and has: the light penetrated from described luminescent layer is resonated and the first resonator structure penetrated between described first electrode and described second electrode; And described light is resonated and the second resonator structure penetrated between described first electrode and described semitransmissive layer, wherein, t is set in 1/4 length of the peak wavelength by the light penetrated from described luminescent layer, when the refractive index of described light-transmitting layer is set to n, the thickness of described light-transmitting layer meets following formula: 0.9 × more than t/n, 1.1 × below t/n.
Description
Technical field
The present invention relates to there is multiple resonant structure organic electric-field light-emitting element (hereinafter sometimes referred to as " organic EL element ".) and use its organic electric field luminescent display.
Background technology
Organic electric-field light-emitting element is the display unit of emissive type, is used in the purposes of display or illumination.Organic electric field luminescent display, compared with CRT or LCD in the past, has the advantage that identification is high, do not have the display performance of angle of visual field dependence and so on.In addition, also having can by display lighting, thin layer advantage.In addition, organic EL illuminating, except lighting, thin layer such advantage, also has the illumination realizing the shape that cannot realize up to now by using flexible base, board.
Said, organic electric-field light-emitting element has excellent feature, but in general, comprises luminescent layer, and the refractive index ratio air forming each layer of display unit is high.Such as, in organic electric-field light-emitting element, the refractive index of the organic thin film layers such as luminescent layer is 1.6 ~ 2.1.Thus, easily there is total reflection at interface in the light sent, also has the situation of its light extraction efficiency less than 20%, thus have lost most light.
Such as, the organic electric field luminescence display part in general known organic electric-field light-emitting element possesses the organic compound layer be configured between pair of electrode layers and forms on substrate.This organic compound layer comprises luminescent layer, and organic electric-field light-emitting element makes the light penetrated from this luminescent layer penetrate from light removing surface side.
But, in this situation, due in the interface of light removing surface or electrode layer and organic compound layer, the total reflection composition belonging to the light of more than critical angle cannot be taken out, therefore there is the problem that the extraction efficiency of light is low.
Based on this kind of situation, in order to improve light extraction efficiency, the organic electric-field light-emitting element (with reference to Japanese Unexamined Patent Publication 2006-140130 publication) with following micro-cavity structure was such as proposed, the optical resonance layer that described microdischarge cavities structure has the photoresonance making to release from light-emitting component and the intermediate layer be clipped between optical resonance layer and light-emitting component.According to above-mentioned organic electric-field light-emitting element, compared with the organic electric-field light-emitting element of non-micro-cavity structure, light extraction efficiency improves.
But, in above-mentioned organic electric-field light-emitting element, owing to using the different transparent material of refractive index as the reflecting surface of light exit side, therefore cannot obtain the volume reflection near vertical incidence fully, there is the light extraction efficiency problem unlikely improved relative to frontal.In addition, because of resonance effects, color and observer is also had to change the problem of (colourity changes) accordingly relative to the position of organic electric-field light-emitting element.
In addition, about the organic electric-field light-emitting element with micro-cavity structure, the organic electric-field light-emitting element (with reference to Japanese Unexamined Patent Publication 2003-123987 publication) of the multiple resonant structure doubly with resonant structure was proposed.The second semi-permeable semi-reflective layer that this organic electric-field light-emitting element possesses completely reflecting mirror, optionally reflects the first semi-permeable semi-reflective layer of first wave length, optionally reflects the second wave length different from above-mentioned first wave length, utilize the first resonance part and the second resonance part that are made up of them, resonate relative to different fundamental wavelengths respectively.
First resonance part is synthesized from the different fundamental wavelength in the second resonance part by above-mentioned organic electric-field light-emitting element, such as, will show blue (λ
1) and orange (λ
2) the light of fundamental wavelength carry out addition colour mixture and send white light.
But, above-mentioned organic electric-field light-emitting element is owing to utilizing complementary colours to realize white, therefore such as when and with when employing the color selecting mechanism of colour filter, produce relative to the position of organic electric-field light-emitting element the problem that colourity changes with observer accordingly with regard to having.
Said, for the organic electric-field light-emitting element with micro-cavity structure, realistic situation is, the inhibition of the raising of light extraction efficiency and colourity change is still abundant not, expects further improvement.
Summary of the invention
The object of the invention is to, provide and not only there is excellent light extraction efficiency but also the organic electric-field light-emitting element changed relative to the colourity that the position of organic electric-field light-emitting element produces accordingly with observer and the organic electric field luminescent display using this organic electric-field light-emitting element can be suppressed.
As the approach for solving the problem, as follows.That is,
<1> organic electric-field light-emitting element, it is characterized in that, be the organic electric-field light-emitting element at least successively with the first electrode, luminescent layer, the second semi-transmissive electrode, intermediate layer, semitransmissive layer and light-transmitting layer, and have: the light penetrated from described luminescent layer is resonated and the first resonator structure penetrated between described first electrode and described second electrode; And described light is resonated and the second resonator structure penetrated between described first electrode and described semitransmissive layer, wherein, t is set in 1/4 length of the peak wavelength by the light penetrated from described luminescent layer, when the refractive index of described light-transmitting layer is set to n, the thickness of described light-transmitting layer meets following formula: 0.9 × more than t/n, 1.1 × below t/n.
In the organic electric-field light-emitting element recorded in above-mentioned <1>, electronics is from the above-mentioned luminescent layer of above-mentioned first electrode injection, hole from the above-mentioned luminescent layer of above-mentioned second electrode injection, in above-mentioned luminescent layer, above-mentioned electronics and above-mentioned hole collision.Once above-mentioned electronics and above-mentioned hole collision, the luminescent material in above-mentioned luminescent layer just obtains energy and becomes excited state, penetrates light when getting back to ground state.The part of above-mentioned light interreflection and resonated and penetrate light between above-mentioned first electrode and above-mentioned second electrode, through above-mentioned intermediate layer, above-mentioned semitransmissive layer and above-mentioned light-transmitting layer externally penetrate.
In addition, the other part of above-mentioned light interreflection and penetrate light with being resonated between above-mentioned first electrode and above-mentioned semitransmissive layer, through above-mentioned intermediate layer, above-mentioned semitransmissive layer and above-mentioned light-transmitting layer externally penetrate.When being set to this formation, light extraction efficiency is just improved.
Thickness due to above-mentioned light-transmitting layer is the thickness roughly equal with the optical length of 1/4th of the peak wavelength of the light penetrated from above-mentioned luminescent layer, therefore except except the above-mentioned raising forming the light extraction efficiency brought, light extraction efficiency can also be improved further.In addition, change relative to the colourity that the position of above-mentioned organic electric-field light-emitting element produces accordingly with observer and have also been obtained suppression.
<2> according to the organic electric-field light-emitting element recorded in above-mentioned <1>, wherein, light-transmitting layer and and the layer that adjoins of this light-transmitting layer between specific refractivity be at least 0.1.
The organic electric-field light-emitting element that <3> records according to any one in above-mentioned <1> to <2>, wherein, the material of semitransmissive layer is metal.
<4> is according to the organic electric-field light-emitting element recorded in above-mentioned <3>, and wherein, metal is selected from least one metal in silver, magnesium-silver alloy and aluminium.
The organic electric-field light-emitting element that <5> records according to any one in above-mentioned <1> to <4>, wherein, luminescent layer contains the phosphorescent material of at least one.
The organic electric-field light-emitting element that <6> records according to any one in above-mentioned <1> to <5>, wherein, organic electric-field light-emitting element is bottom emitting type.
The organic electric-field light-emitting element that <7> records according to any one in above-mentioned <1> to <6>, wherein, between the second electrode and intermediate layer, also there is light-transmitting layer, wherein, t is set in 1/4 length of the peak wavelength by the light penetrated from above-mentioned luminescent layer, when the refractive index of above-mentioned light-transmitting layer is set to n, the thickness of above-mentioned light-transmitting layer meets following formula: 0.9 × more than t/n, 1.1 × below t/n.
The organic electric-field light-emitting element that <8> records according to any one in above-mentioned <1> to <7>, wherein, in the luminescent spectrum of the luminescent material in luminescent layer, front resonant wavelength is shorter than first peak wavelengths several from the short wavelength side of luminescent spectrum, above-mentioned luminescent spectrum meets the relation of the Δ λ < 25nm represented with following mathematical expression 1
< mathematical expression 1>
Δλ＝λ(I0)-λ(0.2×I0)
Wherein, in above-mentioned mathematical expression 1, λ (I0) represents front resonant wavelength, I0 represents the luminous intensity under this wavelength, λ (0.2 × I0) represents wavelength when reaching the luminous intensity of 0.2 times of the luminous intensity of λ (I0), λ (I0) > λ (0.2 × I0).
<9> organic electric field luminescent display, is characterized in that,
There is the redness of organic electric-field light-emitting element as sub-pixel, green, blue each single pixel of any one record in above-mentioned <1> to <8>.
According to the present invention, above-mentioned various problem in the past can be solved, can above-mentioned purpose be reached, can provide and not only there is excellent light extraction efficiency but also the organic electric-field light-emitting element changed relative to the colourity that the position of organic electric-field light-emitting element produces accordingly with observer and the organic electric field luminescent display using this organic electric-field light-emitting element can be suppressed.
Accompanying drawing explanation
Fig. 1 is the summary section of the example representing organic electric-field light-emitting element of the present invention.
Fig. 2 is the summary section of another example representing organic electric-field light-emitting element of the present invention.
Fig. 3 represents not reflected and the curve chart of an example of the shape of the luminescent spectrum of the light of transmission by the second electrode in the middle of the light that penetrates from luminescent layer.
Fig. 4 represents not reflected and the curve chart of another example of the shape of the luminescent spectrum of the light of transmission by the second electrode in the middle of the light that penetrates from luminescent layer.
Fig. 5 is the summary section of the example representing organic electric field luminescent display of the present invention.
Fig. 6 is the curve chart of an example of the dependence of angle of the colourity representing embodiment 1 ~ 3 and comparative example 1 ~ comparative example 2.
Fig. 7 is the curve chart of an example of the relation represented between Δ u ' v ' value and the angle of visual field.
Fig. 8 is the curve chart depending on the luminescent spectrum of the angle of visual field representing comparative example 1.
Fig. 9 is the curve chart depending on the luminescent spectrum of the angle of visual field representing embodiment 1.
Embodiment
(organic electric-field light-emitting element)
Organic electric-field light-emitting element of the present invention at least has the first electrode, luminescent layer, the second semi-transmissive electrode, intermediate layer, semitransmissive layer and light-transmitting layer successively, as required, also there is the functional layer be selected from hole injection layer, hole transporting layer, electron injecting layer and electron supplying layer, in addition, as required, also there is substrate, screen, other component etc.
Above-mentioned organic electric-field light-emitting element has the first resonator structure and the second resonator structure.
-the first electrode, the second electrode-
Above-mentioned first electrode is made up of reflecting electrode, and above-mentioned second electrode is made up of half transmitting electrode.
As above-mentioned first electrode, be form as having the light that makes to penetrate from the above-mentioned luminescent layer electrode to the function of light removing surface lateral reflection.
As the average thickness of above-mentioned first electrode, be not particularly limited, suitably can select according to object, but be preferably more than 50nm.
If above-mentioned average thickness is less than 50nm, then have the situation that cannot obtain enough light reflectivities.
As the average thickness of above-mentioned second electrode, be not particularly limited, suitably can select according to object, but be preferably more than 10nm, be more preferably more than 20nm.
If above-mentioned average thickness is less than 10nm, then has and make a part of transmission from the light of above-mentioned first electrode reflection and the situation that cannot reflect an other part for above-mentioned each light.In addition, also can become high-resistance electrode, thus have the situation of power consumption rising.
As above-mentioned average thickness, electron microscope (Hitachi's system) photo of the cross-section samples such as using probe-type surface shape measuring device (Ulvac Inc., Dektak etc.) or use to make with the FIB method of organic electric-field light-emitting element, measure above-mentioned first electrode of 10 points or the thickness of the second electrode, its mean value is set to average thickness.
As above-mentioned first electrode and above-mentioned second electrode, any one form in anode and negative electrode can be formed, utilize each electrode, form anode and the negative electrode of above-mentioned organic electric-field light-emitting element.
--anode-
Above-mentioned anode is the component to supply holes such as hole injection layer, hole transporting layer, luminescent layers, and can use metal, alloy, metal oxide etc., preferred work function is the material of more than 4eV.
As the material forming above-mentioned anode, be not particularly limited, suitably can select according to object, such as, can enumerate aluminium, gold, silver, chromium, nickel etc.
As the formation method of above-mentioned anode, various method can be used according to above-mentioned material, such as, the methods such as electronic beam method, sputtering method, resistive heating evaporation can be utilized to be formed.
--negative electrode-
Above-mentioned negative electrode is the component to the supply such as electron injecting layer, electron supplying layer, luminescent layer electronics, and adaptation or ionization potential, the stability etc. that can consider to be equal to electron injecting layer, electron supplying layer, luminescent layer the layer that negative electrode adjoins are selected.
As the material of above-mentioned negative electrode, can use metal, alloy, metal oxide etc., preferred work function is the material of below 4eV.
As above-mentioned material, be not particularly limited, suitably can select according to object, such as, can enumerate alkali metal, alkaline-earth metal, rare earth metal, gold, silver, lead, aluminium, sodium-potassium-sodium alloy, lithium-aluminium alloy, magnesium-silver alloy, their hybrid metal etc.
As above-mentioned alkali metal, such as, can enumerate lithium, sodium, potassium or their fluoride etc.
As above-mentioned alkaline-earth metal, such as, can enumerate magnesium, calcium or their fluoride etc.
As above-mentioned rare earth metal, such as, indium, ytterbium etc. can be enumerated.
As the formation method of above-mentioned negative electrode, can according to the various method of materials'use, such as, the methods such as electronic beam method, sputtering method, resistive heating evaporation can be utilized to be formed.
The sheet resistance of above-mentioned anode and negative electrode is more low better, is preferably hundreds of Ω/below.
-luminescent layer-
As the material of above-mentioned luminescent layer, be not particularly limited, suitably can select according to object, the material etc. that can form following layer can be used, namely, having when applying electric field can from anode or hole injection layer, hole transporting layer injected hole, and can inject the function of electronics from negative electrode or electron injecting layer, electron supplying layer; Or make the function of injected electric charge movement; The place be combined again of hole and electronics is provided and makes it luminous function.
As the average thickness of above-mentioned luminescent layer, be not particularly limited, suitably can select according to object, be preferably 1nm ~ 5 μm, be more preferably 5nm ~ 1 μm, be particularly preferably 10nm ~ 500nm.Here, above-mentioned average thickness such as can use the electron micrograph in cross section to measure the thickness of the above-mentioned luminescent layer of 10 points, and its mean value is set to average thickness.
As above-mentioned luminescent layer, containing luminescent material.As above-mentioned luminescent layer, both can only be made up of luminescent material, also can be that luminescent material (in the latter case, is called " photism dopant " or " dopant " by the mixed layer of material of main part and luminescent material sometimes.)。
As above-mentioned luminescent material, be no matter fluorescence luminescent material or phosphorescent material can, also two or more can be mixed, but high efficiency from the viewpoint of obtaining, preferably using phosphorescent material.
As above-mentioned phosphorescent material, in general, the complex compound containing transition metal atoms or lanthanide atom can be enumerated.
As this transition metal atoms, be not particularly limited, suitably can select according to object, such as, can enumerate ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, gold, silver, copper, platinum etc., in the middle of them, more preferably rhenium, iridium, platinum, particularly preferably iridium, platinum.
As the dentate of above-mentioned complex compound, the such as work such as G.Wilkinson, ComprehensiveCoordination Chemistry, Pergamon Press company 1987 distribution, H.Yersin work, the distribution in 1987 of " Photochemistry and Photophysics of Coordination Compounds ", Springer-Verlag company, the bright husband's work in Yamamoto " organometallic chemistry-basis and application-" Shang Hua room company, nineteen eighty-two such as to issue at the middle dentate etc. recorded.
Above-mentioned complex compound both can have 1 transition metal atoms in compound, also can be in addition to have the polynuclear complex of more than 2.Different types of metallic atom can also be contained simultaneously.
In the middle of them, as the concrete example of above-mentioned phosphorescent material, such as, US6303238B1 can be enumerated, US6097147, WO00/57676, WO00/70655, WO01/08230, WO01/39234A2, WO01/41512A1, WO02/02714A2, WO02/15645A1, WO02/44189A1, WO05/19373A2, WO2004/108857A1, WO2005/042444A2, WO2005/042550A1, Japanese Unexamined Patent Publication 2001-247859, Japanese Unexamined Patent Publication 2002-302671, Japanese Unexamined Patent Publication 2002-117978, Japanese Unexamined Patent Publication 2003-133074, Japanese Unexamined Patent Publication 2002-235076, Japanese Unexamined Patent Publication 2003-123982, Japanese Unexamined Patent Publication 2002-170684, EP1211257, Japanese Unexamined Patent Publication 2002-226495, Japanese Unexamined Patent Publication 2002-234894, Japanese Unexamined Patent Publication 2001-247859, Japanese Unexamined Patent Publication 2001-298470, Japanese Unexamined Patent Publication 2002-173674, Japanese Unexamined Patent Publication 2002-203678, Japanese Unexamined Patent Publication 2002-203679, Japanese Unexamined Patent Publication 2004-357791, Japanese Unexamined Patent Publication 2006-93542, Japanese Unexamined Patent Publication 2006-261623, Japanese Unexamined Patent Publication 2006-256999, Japanese Unexamined Patent Publication 2007-19462, Japanese Unexamined Patent Publication 2007-84635, the phosphorescent compound etc. recorded in each publications such as Japanese Unexamined Patent Publication 2007-96259.In the middle of them, preferred Ir complex compound, Pt complex compound, Cu complex compound, Re complex compound, W complex compound, Rh complex compound, Ru complex compound, Pd complex compound, Os complex compound, Eu complex compound, Tb complex compound, Gd complex compound, Dy complex compound, Ce complex compound, more preferably Ir complex compound, Pt complex compound, Re complex compound, further preferably containing metal-carbon key, metal-nitrogen key, metal-oxygen key, the Ir complex compound of the coordination mode of at least one in metal-sulfur key, Pt complex compound, Re complex compound, from luminous efficiency, drive durability, the viewpoints such as colourity are considered, particularly preferably nibble the above Ir complex compound nibbling dentate containing 3 more, Pt complex compound, Re complex compound.
As the concrete example of phosphorescent material operable in the present invention, following compound can be enumerated, but be not limited to them.
As the content of above-mentioned luminescent material, relative to the total compound quality in general forming luminescent layer in luminescent layer, containing 0.1 quality % ~ 50 quality %, but from the viewpoint of durability, external quantum efficiency, preferably containing 1 quality % ~ 50 quality %, more preferably containing 2 quality % ~ 40 quality %.
As aforementioned body material, the cavity conveying material of main part of cavity conveying excellence and the electron-transporting properties material of main part of electron-transporting properties excellence can be used.
As above-mentioned cavity conveying material of main part, such as can enumerate pyrroles, indoles, carbazole, azaindole, azepine carbazole, triazole,
azoles,
diazole, pyrazoles, imidazoles, thiophene, polyaryl alkane, pyrazoline, pyrazolone, phenylenediamine, arylamine, amino chalcones, styryl anthracene, Fluorenone, hydrazone, Stilbene, silazane, aromatic uncle amine compound, styrylamine compounds, aromatic series two methine based compound, porphyrin based compound, polysilane based compound, poly-(N-vinylcarbazole), aniline based copolymer, thiophene oligomers, the electrical conductance high-molecular oligomers things such as polythiophene, organosilan, carbon film, or their derivative etc.In the middle of them, preferred indole derivatives, carbazole derivates, aromatic uncle amine compound, thiophene derivant, more preferably have the compound of carbazyl in molecule, particularly preferably has the compound of tert-butyl group substituted carbazole base.
As above-mentioned electron-transporting properties material of main part, from the viewpoint of raising durability, reduce driving voltage, electron affinity Ea is preferably more than 2.5eV below 3.5eV, is more preferably more than 2.6eV below 3.4eV, is particularly preferably more than 2.8eV below 3.3eV.In addition, from the viewpoint of raising durability, reduce driving voltage, ionization potential Ip is preferably more than 5.7eV below 7.5eV, is more preferably more than 5.8eV below 7.0eV, is particularly preferably more than 5.9eV below 6.5eV.
As above-mentioned electron-transporting properties material of main part, such as can enumerate pyridine, pyrimidine, triazine, imidazoles, pyrazoles, triazole,
azoles,
diazole, Fluorenone, anthraquinone bismethane, anthrone, two benzoquinones, thiopyrandioxide, carbodiimide, fluorenylidene-methane, distyrylpyrazine, fluorine substituted aromatic compound, naphthalene condensed ring tetracarboxylic anhydride, phthalocyanine or their derivatives (also can form condensed ring with other ring) such as perylene (naphthalene perylene), with the metal complex of the oxine derivatives such as BAlq or by metal phthalocyanine, benzo
azoles or benzothiazole are the various metal complexs etc. of representative as the metal complex of dentate.
As above-mentioned electron-transporting properties material of main part, preferable alloy complex compound, Zole derivatives (benzimidizole derivatives, imidazopyridine derivatives etc.), azine derivatives (pyridine derivate, pyrimidine derivatives, pyrrolotriazine derivatives etc.), wherein, from the viewpoint of durability, more preferably metal complex.Metal complex (A) preferably possesses the metal complex had with at least any one the dentate of the nitrogen-atoms of metal-complexing, oxygen atom and sulphur atom.
Metal ion in metal complex is not particularly limited, and suitably can select according to object, such as, can enumerate beryllium ion, magnesium ion, aluminium ion, gallium ion, zinc ion, indium ion, tin ion, platinum ion or palladium ion etc.In the middle of them, preferred beryllium ion, aluminium ion, gallium ion, zinc ion, platinum ion or palladium ion, more preferably aluminium ion, zinc ion or palladium ion.
As dentate contained in above-mentioned metal complex, as long as various known dentate, the middle dentate recorded such as such as can enumerate " Photochemistry and Photophysics of CoordinationCompounds ", Springer-Verlag company, H.Yersin work, distribution in 1987, " organometallic chemistry-basis with application-", Shang Hua room company, the bright husband's work in Yamamoto, nineteen eighty-two issue.
As above-mentioned dentate, more preferably nitrogen heterocyclic ring dentate (preferred carbon number is 1 ~ 30, and more preferably carbon number is 2 ~ 20, and particularly preferably carbon number is 3 ~ 15).In addition, as above-mentioned dentate, both can be singly nibble dentate, also 2 can nibble above dentate, and be preferably 2 and nibble above 6 and nibble following dentate.In addition, also preferably 2 the above 6 mixed ligand bases nibbled following dentate and singly nibble are nibbled.
As above-mentioned dentate, such as, can enumerate azine dentate and (such as can enumerate pyridine coordination base, bipyridine dentate, terpyridyl dentate etc.), hydroxy phenyl azoles dentate (such as can enumerate hydroxy phenyl benzimidazole dentate, hydroxy phenyl benzo
azoles dentate, hydroxy phenyl imidazoles dentate, hydroxy phenyl imidazopyridine dentate etc.), (such as can enumerate methoxyl group, ethyoxyl, butoxy, 2-ethyl hexyl oxy etc., preferred carbon number is 1 ~ 30 to alkoxyl dentate, and more preferably carbon number is 1 ~ 20, and particularly preferably carbon number is 1 ~ 10.), (such as can enumerate phenoxy group, 1-naphthoxy, 2-naphthoxy, 2,4,6-trimethyl phenoxy groups, 4-xenyl oxygen base etc., preferred carbon number is 6 ~ 30 to aryloxy group dentate, and more preferably carbon number is 6 ~ 20, and particularly preferably carbon number is 6 ~ 12.), (such as can enumerate pyridine oxygen base, pyrazine oxygen base, 2-pyrimidinyl oxy, quinoline oxy etc., preferred carbon number is 1 ~ 30 to heteroaryloxy dentate, and more preferably carbon number is 1 ~ 20, and particularly preferably carbon number is 1 ~ 12.), (such as can enumerate methyl mercapto, ethylmercapto group etc., preferred carbon number is 1 ~ 30 to alkylthio group dentate, and more preferably carbon number is 1 ~ 20, and particularly preferably carbon number is 1 ~ 12.), (such as can enumerate thiophenyl etc., preferred carbon number is 6 ~ 30 to arylthio dentate, and more preferably carbon number is 6 ~ 20, and particularly preferably carbon number is 6 ~ 12.), heteroarylthio dentate (such as can enumerate pyridine thio, 2-benzimidazole sulfenyl, 2-benzo
azoles sulfenyl, 2-[4-morpholinodithio sulfenyl etc., preferred carbon number is 1 ~ 30, and more preferably carbon number is 1 ~ 20, and particularly preferably carbon number is 1 ~ 12.), (such as can enumerate triphenylsiloxy group, triethoxysilyl, triisopropyl siloxy etc., preferred carbon number is 1 ~ 30 to siloxy dentate, and more preferably carbon number is 3 ~ 25, and particularly preferably carbon number is 6 ~ 20.), (such as can enumerate phenyl anion, naphthyl anion and anthryl anion etc., preferred carbon number is 6 ~ 30 to aromatic hydrocarbon anion binding base, and more preferably carbon number is 6 ~ 25, and particularly preferably carbon number is 6 ~ 20.), heteroaromatic anion binding base (such as can enumerate pyrroles's anion, pyrazole anion, pyrazole anion, triazole anion,
azoles anion, benzo
azoles anion, thiazole anion, benzothiazole anion, thiophene anion and benzothiophene anion etc., preferred carbon number is 1 ~ 30, and more preferably carbon number is 2 ~ 25, and particularly preferably carbon number is 2 ~ 20.), indole anion dentate etc., preferred nitrogen heterocyclic ring dentate, aryloxy group dentate, heteroaryloxy dentate, siloxy dentate etc., more preferably nitrogen heterocyclic ring dentate, aryloxy group dentate, siloxy dentate, aromatic hydrocarbon anion binding base, heteroaromatic anion binding base etc.
As the example of above-mentioned metal complex electron-transporting properties main body, such as, can enumerate the compound recorded in each publications such as Japanese Unexamined Patent Publication 2002-235076, Japanese Unexamined Patent Publication 2004-214179, Japanese Unexamined Patent Publication 2004-221062, Japanese Unexamined Patent Publication 2004-221065, Japanese Unexamined Patent Publication 2004-221068, Japanese Unexamined Patent Publication 2004-327313.
As the triplet lowest excited energy level (T1) of aforementioned body material, from the viewpoint of colour purity, luminous efficiency, driving durability, preferably higher than the T1 of above-mentioned phosphorescent material.
As the content of aforementioned body material, be not particularly limited, but from the viewpoint of luminous efficiency, driving voltage, relative to the total compound quality forming luminescent layer, be preferably below more than 15 quality % 95 quality %.
As the formation method of above-mentioned luminescent layer, be not particularly limited, suitably can select according to object, such as, can enumerate the methods such as resistance heating evaporation, electron beam, sputtering, molecule layered manner, cladding process, LB method.In the middle of them, particularly preferably resistance heating evaporation, cladding process.
As above-mentioned cladding process, such as, can enumerate spin-coating method, the tape casting, dip coating etc.
-hole injection layer, hole transporting layer-
As the material of above-mentioned hole injection layer and hole transporting layer, as long as have from the function in the function of anode injected hole, conveying hole, stop any one material from the function of negative electrode injected electrons, just be not particularly limited, suitably can select according to object.
As the material of above-mentioned hole injection layer and hole transporting layer, such as can enumerate carbazole derivates, triazole derivative,
zole derivatives,
oxadiazole derivative, imdazole derivatives, polyaryl chain alkane derivatives, pyrazoline derivative, pyrazolone derivative, phenylenediamine derivative, arylamine derivatives, amino chalcones derivative, styrylanthracene derivatives, fluorenone derivatives, hydazone derivative, stilbene derivative, silazane derivatives, aromatic uncle amine compound, styrylamine compounds, aromatic series two methine based compound, porphyrin based compound, polysilane based compound, poly-(N-vinylcarbazole) derivative, aniline based copolymer, thiophene oligomers, the electroconductive polymer oligomer etc. such as polythiophene.They both can be used alone or two or more kinds may be used.
As above-mentioned hole injection layer and hole transporting layer, both can be by the one kind or two or more single layer structure formed of above-mentioned material, also can be made up of or sandwich construction that the different multiple layers formed are formed same.
As the formation method of above-mentioned hole injection layer and hole transporting layer, such as, can use vacuum vapour deposition, LB method, hole injectant and cavity conveying agent are dissolved or dispersed in the method (spin-coating method, the tape casting, dip coating etc.) of coating in solvent.When cladding process, can dissolve together with resinous principle or disperse.
As above-mentioned resinous principle, be not particularly limited, suitably can select according to object, such as Corvic can be enumerated, polycarbonate resin, polystyrene resin, plexiglass, polybutylene terephthalate (PBT) resin, mylar, polysulfone resin, polyphenylene oxide resin, polybutadiene, poly-(N-vinylcarbazole) resin, hydrocarbon resin, ketone resin, phenoxy resin, polyamide, ethyl cellulose, vinyl acetate resin, ABS resin, polyurethane resin, melamine resin, unsaturated polyester resin, alkyd resins, epoxy resin, silicone resin etc.They both can be used alone or two or more kinds may be used.
As the thickness of above-mentioned hole injection layer and hole transporting layer, be not particularly limited, suitably can select according to object, such as, be preferably 1nm ~ 5 μm, be more preferably 5nm ~ 1 μm, be particularly preferably 10nm ~ 500nm.As above-mentioned average thickness, such as, the electron micrograph in cross section can be used to measure the above-mentioned hole injection layer of 10 points or the thickness of hole transporting layer, its mean value is set to average thickness.
-electron injecting layer, electron supplying layer-
As the material of above-mentioned electron injecting layer and electron supplying layer, as long as have from negative electrode inject the function of electronics, conveying electronic function, stop any one material from the function of anode injected holes, just be not particularly limited, suitably can select according to object.
As the material of above-mentioned electron injecting layer and electron supplying layer, such as can enumerate triazole derivative,
zole derivatives,
the condensed ring tetracarboxylic anhydrides such as oxadiazole derivative, fluorenone derivatives, anthraquinone bismethane derivative, anthracyclinone derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, carbodiimide derivative, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, Nai perylene, phthalocyanine derivates, with the metal complex of oxine derivative or by metal phthalocyanine, benzo
azoles or benzothiazole are the various metal complexs etc. of representative as the metal complex of dentate.They both can be used alone or two or more kinds may be used.
As above-mentioned electron injecting layer and electron supplying layer, both can be by the one kind or two or more single layer structure formed of above-mentioned material, also can be made up of or sandwich construction that the different multiple layers formed are formed same.
As the formation method of above-mentioned electron injecting layer and electron supplying layer, such as, can use vacuum vapour deposition or LB method, electron injection agent and electron transporting agent are dissolved or dispersed in the method (spin-coating method, the tape casting, dip coating etc.) of coating in solvent.When cladding process, can dissolve together with resinous principle or disperse.As above-mentioned resinous principle, such as, when can be applied in hole injection layer and hole transporting layer illustrated material.
As the thickness of above-mentioned electron injecting layer and electron supplying layer, be not particularly limited, suitably can select according to object, be preferably 1nm ~ 5 μm, be more preferably 5nm ~ 1 μm, be particularly preferably 10nm ~ 500nm.As above-mentioned average thickness, such as, the electron micrograph in cross section can be used to measure the above-mentioned electron injecting layer of 10 points or the thickness of electron supplying layer, its mean value is set to average thickness.
-intermediate layer-
As above-mentioned intermediate layer, be in the light removing surface side of above-mentioned second electrode, there is the function of adjustment as the length of the light of advancing in this intermediate layer of the optical path length of incident light.
As above-mentioned intermediate layer, as long as have the material of above-mentioned functions, just be not particularly limited, such as can enumerate following material etc., namely, in the first electrode and semitransmissive layer reflex time phase difference and be 2 π integral multiple time, after the peak luminous wavelength in luminescent layer is set to λ, the integral multiple of λ/2 will be adjusted to the optical path length of above-mentioned semitransmissive layer from above-mentioned first electrode.
As above-mentioned intermediate layer, as long as this kind of form, then for shape, structure, size etc., be just not particularly limited, suitably can select according to object.
As the material in above-mentioned intermediate layer, as long as the material of significantly impact can not be caused on the wavelength of incident light or luminous intensity, just be not particularly limited, optically transparent inorganic and organic various material can be enumerated, such as, can enumerate the transparent resins such as polyacrylate, polymethyl methacrylate, polyimides.
As the formation method in above-mentioned intermediate layer, be not particularly limited, suitably can select according to object, such as, can enumerate the methods such as electronic beam method, sputtering method, resistive heating evaporation, spin-coating method, spraying process, ink-jet method.
As the thickness in above-mentioned intermediate layer, be adjusted to the colourity that can suppress to be caused by the angle of the light of the wavelength observing regulation to change, specifically, according to following general formula (1) and general formula (2), by the material be held between the first electrode and intermediate layer refractive index and form, the decision such as thickness.
general formula (1)
Wherein, in above-mentioned general formula (1), n represents the refractive index of each layer, d
1represent the distance between the luminescent layer side surface of above-mentioned first electrode and this luminescent layer side surface of above-mentioned second electrode, m represents number of times, φ
0represent the reflected phase will side-play amount at the first electrode place, φ
1represent the reflected phase will side-play amount at the second electrode place, φ
2represent the reflected phase will side-play amount at semitransmissive layer place, λ 1 represents the peak wavelength of the light sent.
general formula (2)
Wherein, in above-mentioned general formula (2), n represents the refractive index of each layer, d
2distance between the surface representing the luminescent layer side surface of above-mentioned first electrode and the above-mentioned luminescent layer side in above-mentioned intermediate layer, m represents number of times, φ
0represent the reflected phase will side-play amount at the first electrode place, φ
1represent the reflected phase will side-play amount at the second electrode place, φ
2represent the reflected phase will side-play amount at semitransmissive layer place, λ 1 represents the peak wavelength of the light sent.
Above-mentioned general formula (1) represents resonance condition when observing the light of wavelength X 1 from frontal (θ=0 °).Above-mentioned so-called frontal refers to, draws vertical line, the direction when angle of visual field (θ) seen from this direction is 0 ° from aforesaid substrate to above-mentioned luminescent layer.
Above-mentioned general formula (2) represents resonance condition when observing the light of wavelength X 1 from 45 ° of directions (θ=45 °).Above-mentioned so-called 45 ° of directions refer to, draw vertical line from aforesaid substrate to above-mentioned luminescent layer, when the angle of visual field (θ) in this direction is set to 0 °, and the direction when angle of visual field (θ) is 45 °.
By the relation making the thickness in above-mentioned intermediate layer meet above-mentioned general formula (1) and general formula (2), even if observer is moved (movement) relative to the position of organic electric-field light-emitting element to the high angle side that 45 ° (angle of visual field 45 °) is such, utilize the distance d for the observation from high angle
2the effect of resonator length, also can continue the light radiating wavelength X 1 in high angle side.
Although at the frontal of aforesaid substrate, take out and utilize distance d
1resonator length obtain the wavelength X 1 of resonance effects, but when observer moves to high angle side relative to the position of organic electric-field light-emitting element, then resonant wavelength will move to short wavelength side.At this moment, due to by distance d
1the resonance effects brought diminishes, and therefore luminous intensity diminishes.
But, observer relative to the position of above-mentioned organic electric-field light-emitting element close to such high angle side, the face of above-mentioned organic electric-field light-emitting element, in above-mentioned general formula (2), due to distance d
2be in the relation of the resonator length meeting wavelength X 1, therefore utilize by distance d
2wavelength X 1 light takes out by resonance effects again consumingly that bring, even if so change observer relative to the position of organic electric-field light-emitting element, also can suppress spectrum change amount.
But the peak value of spectrum or the angle variable quantity of colourity, as provided in Fig. 3 and Fig. 4 shown in an example, depend on the shape of the luminescent spectrum of luminescent material.Resonant wavelength such as shown in Figure 8, along with the angle of visual field becomes large, moves to short wavelength.Luminescent material is owing to being also luminous from short wavelength side, and therefore the luminous intensity of short wavelength side will be strengthened, and angle of visual field dependency characteristic (colourity corresponding with the position of observer changes) changes.Thus, the consistent wavelength that front resonant wavelength is shorter with first peak wavelengths several than the short wavelength side from above-mentioned luminescent spectrum is preferably made.The luminous intensity of the peak wavelength of luminescent material is set to 1, then can shows by following mathematical expression 1 and be in the wavelength side shorter than above-mentioned peak wavelength and luminous intensity reaches the slope of the short wavelength side of the above-mentioned luminescent spectrum till 0.2.
< mathematical expression 1>
Δλ＝λ(I0)-λ(0.2×I0)
Wherein, in above-mentioned mathematical expression 1, λ (I0) represents front resonant wavelength, I0 represents the luminous intensity under this wavelength, λ (0.2 × I0) represents wavelength when reaching the luminous intensity of 0.2 times of the luminous intensity of λ (I0), λ (I0) > λ (0.2 × I0).
And being defined as the luminous intensity Δ λ reached till 0.2 is because if less than 0.2, then the SN ratio of light emitting elements will be deteriorated, and noise becomes many.
If the Δ λ of above-mentioned mathematical expression 1 is little, then colourity can be suppressed to change.Δ λ as shown in Figure 3, Figure 4, represents the slope of the wavelength side shorter than the peak wavelength of luminescent spectrum.Δ λ is less, then as shown in Figure 3, steeper slopes is high and steep, and Δ λ is larger, then as shown in Figure 4, slope is milder.
If Δ λ is large, even if then due to angle of visual field change (observer is relative to the change in location of organic electric-field light-emitting element), also have the light emitting elements that much can resonate, therefore will strengthen in short wavelength side luminous intensity, angle of visual field dependency characteristic changes.
According to the achievement of the further investigation of the present inventor etc., obtain following opinion, that is, in organic electric-field light-emitting element of the present invention, if make Δ λ be less than 25nm, then the change of tone is just inhibited, and meets the performance as display.
Change as above-mentioned colourity, as shown in Figure 7, use Δ u ' v ' value.Change as above-mentioned colourity, represent with the variable quantity of each angle counted from u ' v ' value time front (angle of visual field 0 °).Known in the display devices such as display, if in general Δ u ' v ' is more than 0.02, not ideal enough.
Such as, for red (in Fig. 7, Δ λ=25nm (resonant wavelength is short wavelength side)), if in Δ λ < 25nm, with the index Δ u ' v ' of the scope of the angle of visual field 0 ° ~ 80 ° observation colourity change, then colourity variable quantity can be suppressed below 0.02.In addition, as shown in Figure 7, for blue (in Fig. 7, Δ λ=20nm) or green (in Fig. 7, Δ λ=15nm), also can similarly Results.And when resonant wavelength being set in the wavelength side longer than the peak wavelength of luminescent spectrum, then as shown in Figure 7, Δ u ' v ' value can more than 0.02.Like this, by resonant wavelength being set to the wavelength side shorter than peak wavelength, Δ λ being set to and being less than 25nm, colourity just can be suppressed to change.
Specifically, as the average thickness in above-mentioned intermediate layer, can change according to the color of the light penetrated from above-mentioned luminescent layer, such as, determine as shown below when redness.
When the peak wavelength of the light taken out to frontal is set to 620nm, for the total of thickness of the first resonator structure comprising luminescent layer etc., according to general formula (1), for 324nm, when the refractive index in intermediate layer is set to 1.8, if ask the thickness of the second resonator structure according to general formula (2), be then 465nm.
So the thickness deducting the average thickness of the second electrode from its difference is exactly the average thickness in intermediate layer, in this situation, 130nm is best.
In above-mentioned intermediate layer, because luminescent spectrum is wide, therefore ± about 5nm is range of allowable error.Also can be set as the angle side lower than 45 ° of directions by suppressing the angular regions of the peak wavelength migration depending on the angle of visual field, if 40 ° of directions, then according to general formula (2), the average thickness in intermediate layer is 90nm.If be set to low angle further, then peak wavelength migration will become large in high angle side, thus occurs the problem of the tone damaging high angle side.
So in this situation, the thickness in intermediate layer is preferably 85 ~ 135nm, is more preferably 125 ~ 135nm.
If above-mentioned average thickness is less than 85nm or more than 135nm, then the position along with observer is different, colourity change or color displacement will become greatly, and the raising of efficiency tails off, thus has the situation that cannot obtain effect of the present invention.
Here, as above-mentioned average thickness, such as, can use the electron micrograph in cross section, measure the thickness in the above-mentioned intermediate layer of 10 points, its mean value is set to average thickness.
In addition, when green and blue, the principle identical with the situation of redness also can be utilized to obtain average thickness.
-semitransmissive layer-
Above-mentioned semitransmissive layer is between above-mentioned intermediate layer and above-mentioned light-transmitting layer, has the light that makes to penetrate from above-mentioned luminescent layer and from a part of transmission of the light of above-mentioned first electrode reflection and by the function of the other part reflection of above-mentioned each light.
As the material of above-mentioned semitransmissive layer, be not particularly limited, suitably can select according to object, such as, can enumerate metal etc.
As above-mentioned metal, such as, can enumerate silver, magnesium-silver alloy, aluminium etc.
As the formation method of above-mentioned semitransmissive layer, be not particularly limited, suitably can select according to object, such as, can enumerate the methods such as electronic beam method, sputtering method, resistive heating evaporation.
As the average thickness of above-mentioned semitransmissive layer, be not particularly limited, suitably can select according to object, such as, be preferably 3nm ~ 50nm, be more preferably 5nm ~ 40nm, be particularly preferably 10nm ~ 30nm.
If above-mentioned average thickness is less than 3nm, then because reflectivity is low, therefore have the situation that cannot obtain effect of the present invention, if more than 10nm, then because transmissivity is low, therefore have the situation that cannot obtain effect of the present invention.
Here, as above-mentioned average thickness, such as, can use the electron micrograph in cross section, measure the thickness of the above-mentioned semitransmissive layer of 10 points, its mean value is set to average thickness.
In addition, as the average thickness of above-mentioned semitransmissive layer, in order to improve optical distance d
1resonance effects, preferably make average thickness thinner than above-mentioned second electrode.As the average thickness of above-mentioned semitransmissive layer and the ratio (average thickness of average thickness/the second electrode of semitransmissive layer) of the average thickness of above-mentioned second electrode, be preferably 0.1 ~ 2, be more preferably 0.2 ~ 1.5, be particularly preferably 0.4 ~ 1.
If the ratio of above-mentioned average thickness is less than 0.1, then reflectivity is abundant not, have the situation that cannot obtain effect of the present invention, if more than 2, then have cannot strengthen as target wavelength or the situation of colourity inhibition when watching from high angle side cannot be obtained.
-light-transmitting layer-
Above-mentioned light-transmitting layer is at least between substrate and above-mentioned semitransmissive layer, there is following function, that is, by the phase cancellation of the reverberation of above-mentioned semitransmissive layer and substrate interface, increase the transmission amount of light to aforesaid substrate, suppress the colourity change caused by observed angle simultaneously.
As above-mentioned light-transmitting layer, as long as have this kind of function, then shape, structure, size etc. are just not particularly limited, suitably can select according to object.
As the material of above-mentioned light-transmitting layer, be not particularly limited, suitably can select according to object, such as, can enumerate magnesium fluoride, Alq, Cytop (Asahi Glass Inc.), SiNx etc.
Such as, as above-mentioned light-transmitting layer, as provided shown in an example in Fig. 2, also except between aforesaid substrate and above-mentioned semitransmissive layer, also can have between above-mentioned second electrode and above-mentioned intermediate layer.Forming by being set to this kind, just can improve the anti-reflection effect at the interface of the second electrode, light extraction efficiency can be improved further.
As the average thickness of above-mentioned light-transmitting layer, be set to t in 1/4 length of the peak wavelength by the light penetrated from above-mentioned luminescent layer, when the refractive index of above-mentioned light-transmitting layer is set to n, be preferably 0.9 × more than t/n, 1.1 × below t/n.
If above-mentioned average thickness is less than 0.9 × t/n, then has and cannot obtain the situation that the light extraction efficiency brought by effect of the present invention improves effect, if more than 1.1 × t/n, then can different situation light extraction efficiency being reduced on the contrary because of absorption of with good grounds material.
Specifically, such as, peak wavelength being set to red 620nm, by MgF
2when being set to material, due to MgF
2refractive index be 1.38, therefore 101nm ~ 123.5nm is suitable.If consider by reflect the phase place change that causes etc. as a whole structure carry out optimization, then can be compared to most the thin 10nm of 101nm ~ 123.5nm, be therefore preferably 91nm ~ 113.5nm.
In above-mentioned light-transmitting layer, because luminescent spectrum is wide, ± about 5nm is allowed in the change therefore as thickness.So, as the average thickness of light-transmitting layer, be more preferably 86nm ~ 118.5nm.
As above-mentioned average thickness, such as, can use the electron micrograph in cross section, measure the thickness of the above-mentioned light-transmitting layer of 10 points, its mean value is set to average thickness.
As the specific refractivity (Δ n) between above-mentioned light-transmitting layer and adjacent layer, if due to (Δ n) large, then boundary reflection rate improves, and therefore effect is emphasized further, so be at least 0.1.
If above-mentioned refringence is less than 0.1, then reflectivity is low, therefore has the situation that cannot obtain resonant structure required for the present invention.Here, the layer that above-mentioned what is called is adjacent, refers to substrate, semitransmissive layer in FIG, refers to substrate, semitransmissive layer, intermediate layer and the second electrode in fig. 2.Above-mentioned refractive index can use ellipsometer (hole field makes made) to measure.
-substrate-
As aforesaid substrate, as long as suitably select its shape, structure, size etc., in general, as the shape of substrate, preferred tabular.As the structure of substrate, both can be single layer structure, and also can be stepped construction, in addition, both can be formed by solid memder, also can be formed by the component of more than 2.
As aforesaid substrate, both can be water white, also can be colored transparent, but the aspects such as the light scattering that sends from luminescent layer or decay always can not be made to consider, preferably water white.
As the material of aforesaid substrate, be not particularly limited, suitably can select according to object, such as, can enumerate the inorganic material such as yttria-stabilized zirconia (YSZ), glass, pet resin, polybutylene terephthalate (PBT), PEN resin, mylar, polystyrene resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, polyimide resin, polycyclic olefin resin, norbornene resin, poly-(chlorotrifluoroethylene) resin etc.They both can be used alone or two or more kinds may be used.
When using glass as aforesaid substrate, for its material, in order to reduce the released ion from glass, preferably use alkali-free glass.In addition, when using soda-lime glass, preferably use the glass (such as barrier layer substrate) being coated with the barrier layers such as silicon dioxide.When organic material, preferably excellent in thermal endurance, dimensional stability, solvent resistance, electrical insulating property and processability.
When using above-mentioned thermoplasticity substrate, also as required, also hard conating, priming coat etc. can be set.
Also can on aforesaid substrate, configuration makes the planarization layer of this upper shape planarization, and this planarization layer configures above-mentioned light-transmitting layer etc.
As the material of this planarization layer, be not particularly limited, suitably can select according to object, such as, can enumerate SiO
2, SiON, polyimides etc.
The example of Fig. 2 to the execution mode of the organic electric-field light-emitting element of the present invention formed as described above is used to be described.
Above-mentioned organic electric-field light-emitting element 100 is configured with the first electrode 9, electron supplying layer 8, light-emitting component 7, hole transporting layer 6, second electrode 5, intermediate layer 4, semitransmissive layer 3, light-transmitting layer 2, substrate 1 successively.
In this organic electric-field light-emitting element 100, play a role as the first resonator structure be made up of the first electrode 9, electron supplying layer 8, luminescent layer 7, hole transporting layer 6 and the second electrode 5, and play a role as the second resonator structure be made up of the first electrode 9, electron supplying layer 8, luminescent layer 7, hole transporting layer 6, second electrode 5, intermediate layer 4 and semitransmissive layer 3.
In the organic electric-field light-emitting element 100 so formed, in above-mentioned frontal (θ=0 °), penetrate by optical distance d
1the light of wavelength X 1 selected of resonator length.Different with it, the angle observed by counting from optical axis direction becomes large direction, utilizes the optical distance d for the observation from high angle
2the effect of resonator length, also can continue the light penetrating wavelength X 1 in high angle side.Consequently, the colourity produced accordingly relative to the position of organic electric-field light-emitting element with observer can be suppressed to change.
As organic electric-field light-emitting element of the present invention, when considering large-area luminaire, consider from electrical characteristics such as the sheet resistances of transparency electrode, be preferably set to the formation of the bottom emitting type taking out light from aforesaid substrate 1 side.
(organic electric field luminescent display)
Organic electric field luminescent display of the present invention has above-mentioned organic electric-field light-emitting element, as required, can apply other formation.As other formation above-mentioned, be not particularly limited, suitably can select according to object, as the necessary item of display, all known mechanisms can be applied.
As above-mentioned organic electric field luminescent display, as provided shown in an example in Fig. 5, by making, with the varied in thickness in red (R), green (G), above-mentioned intermediate layer that blue (B) is corresponding, to take out the light of colors.Forming by being set to this kind, just can have excellent light extraction efficiency, and power consumption is low, the colourity change caused by observed angle can be suppressed.
Embodiment
Below, embodiments of the invention are described, but the present invention is not by any restriction of these embodiments.And, for the Refractive Index of Material in embodiment, as long as no particularly pointing out, be exactly the measured value by analysis of polarized light determination method.Analysis of polarized light determination method is by the assay method of monochromatic source to polariscopic angle scanning, therefore records the refractive index under its optical source wavelength.Light source employs the He-Ne laser of wavelength 632.8nm.
(embodiment 1)
The making > of < organic electric-field light-emitting element
Be on the glass substrate of 1.51 in thick 0.7mm, refractive index, as light-transmitting layer, according to the mode making thickness reach 100nm, utilize vacuum evaporation to form MgF
2.Ellipsometer is used to measure the refractive index of light-transmitting layer, consequently 1.38.
On light-transmitting layer, as semitransmissive layer, according to the mode making thickness reach 12nm, vacuum evaporation is utilized to form silver (Ag).
In semitransmissive layer, as intermediate layer, according to the mode making thickness reach 130nm, vacuum evaporation is utilized to form Alq (three (oxine) aluminium).Ellipsometer is used to measure the refractive index of Alq, consequently 1.74.
Then, on the intermediate layer, as the second electrode (anode), according to the mode making thickness reach 20nm, utilize vacuum evaporation to form silver (Ag), formed silverskin is contacted with electrode terminal.
On the second electrode, as hole transporting layer, according to the mode making thickness reach 235nm, vacuum evaporation is utilized to be formed in 2-TNATA (4,4 ', 4 "-three (2-naphthylphenyl amino) triphenylamine) F4-TCNQ (2; 3; 5,6-tetra-fluoro-7,7; 8; 8-four cyano quinone bismethane) being doped with 1.0%, then, on hole transporting layer; according to the mode making thickness reach 10nm, vacuum evaporation NPD (N, N '-diphenyl-N, N '-two (Alpha-Naphthyl)-benzidine).
Then, on NPD, using the BAlq (aluminium (III) two (2-methyl-8-quinoline) 4-benzene substituting phenol base) as material of main part, the luminescent material A represented with following structural formula as luminescent material with the ratio of mass ratio 95: 5, according to the mode making thickness reach 30nm, utilize vacuum co evaporation to plate, form luminescent layer.And the ratio of the signal of the quartz crystal unit will monitored out with CRTM9000 (Ulvac Inc.) is as mass ratio.
Then, on luminescent layer, as electron supplying layer, according to the mode making thickness reach 39nm, utilize vacuum evaporation to form BAlq (aluminium (III) two (2-methyl-8-quinoline) 4-benzene substituting phenol base).In order to make electron injection good, according to the mode making thickness reach 1nm, vacuum evaporation BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), then according to the mode making thickness reach 1nm, vacuum evaporation LiF.
Then, by LiF, as the first electrode (negative electrode), according to the mode making thickness reach 100nm, utilize vacuum evaporation to form Al, and produce organic electric-field light-emitting element (1).
The organic electric-field light-emitting element (1) of gained has the micro-cavity structure of two dimension, and made organic electric-field light-emitting element (1) is the element of optimization the luminescence concerning red (about 620nm).
(embodiment 2)
The making > of < organic electric-field light-emitting element
Except in embodiment 1, formed beyond light-transmitting layer as shown below, made organic electric-field light-emitting element (2) identically with embodiment 1.
-formation of light-transmitting layer-
On the glass substrate of thick 0.7mm, refractive index 1.51, as light-transmitting layer, according to the mode making thickness reach 112nm, vacuum evaporation is utilized to define MgF
2.Ellipsometer is used to measure the refractive index of light-transmitting layer, consequently 1.38.
The organic electric-field light-emitting element (2) of gained has the micro-cavity structure of two dimension, and made organic electric-field light-emitting element (2) is the element of optimization the luminescence concerning red (about 620nm).
(embodiment 3)
The making > of < organic electric-field light-emitting element
Except in embodiment 1, formed beyond intermediate layer as shown below, made organic electric-field light-emitting element (3) identically with embodiment 1.
-formation in intermediate layer-
In semitransmissive layer, as intermediate layer, the MgF with the thickness evaporation of 30nm
2, next according to the mode making thickness reach 100nm, utilize vacuum evaporation to define ITO.Ellipsometer is used to measure respective refractive index, consequently, MgF
2be 1.38, ITO be 1.98.
The organic electric-field light-emitting element (3) of gained has the micro-cavity structure of two dimension, and made organic electric-field light-emitting element (3) is the element of optimization the luminescence concerning red (about 620nm).
(comparative example 1)
The making > of < organic electric-field light-emitting element
Except in embodiment 1, be set to not there is light-transmitting layer, semitransmissive layer and intermediate layer formation beyond, made organic electric-field light-emitting element (4) identically with embodiment 1.
(comparative example 2)
The making > of < organic electric-field light-emitting element
Except in embodiment 1, be set to not there is light-transmitting layer formation beyond, made organic electric-field light-emitting element (5) identically with embodiment 1.
(evaluation)
The colourity corresponding relative to the position of organic electric-field light-emitting element with observer that have rated made each organic electric-field light-emitting element as shown below changes and light extraction efficiency.In addition, for embodiment 1 and comparative example 1, luminescent spectrum is determined as shown below.
-colourity corresponding relative to the position of organic electric-field light-emitting element with observer changes-
Made each organic electric-field light-emitting element is erect configuration, according to x, y chromaticity coordinate derived from spectrum, standard based on CIE1976 is obtained each angle and (is drawn vertical line from aforesaid substrate to above-mentioned luminescent layer, the angle of visual field seen from this direction is set to 0 °, with above-mentioned vertical line for benchmark in the lateral direction every 5 ° of ground offset straight to ± 85 °) u ', the v ' of cie color coordinate.The results are shown in Fig. 6.
-light extraction efficiency-
Make made each organic electric-field light-emitting element luminous, utilize quantometer (multichannel optical splitter, Oceanphotonics Co., Ltd. system) to determine its light quantity.Based on the light quantity determined, calculate light extraction efficiency.The results are shown in Table 1.
< changes the mensuration > of the luminescent spectrum of the angle of visual field
To the organic electric-field light-emitting element of made embodiment 1 and comparative example 1, by make rotary sample in angle measurement platform (gonio stage) while, determine luminescent spectrum with light splitting brightness photometer 2000 (Unica Minolta Inc.).The result of embodiment 1 is shown in Fig. 8, the result of comparative example 1 is shown in Fig. 9.
[table 1]
| Embodiment 1 | Embodiment 2 | Embodiment 3 | Comparative example 1 | Comparative example 2 | |
| Efficiency (cd/A) | 18.08 | 18.11 | 18.26 | 14.83 | 17.28 |
Wherein, in table 1, said efficiency represents 1000cd/m
2time electric current briliancy efficiency.
Known according to table 1, embodiment 1 ~ 3 is compared with comparative example 1 ~ 2, and light extraction efficiency improves.
In addition, according to Fig. 6, the Δ u ' v ' value of embodiment 1 ~ 3 is 0.02, and in comparative example 1 ~ comparative example 2, Δ u ' v ' value is far away from more than 0.02.It can thus be appreciated that in embodiment 1 ~ 3, the colourity corresponding relative to the position of organic electric-field light-emitting element with observer changes the suppression obtained very greatly.
In addition, as shown in Figure 8, the luminescent spectrum of known comparative example 1 becomes large along with the angle of visual field, and the peak of spectrum moves to short wavelength side, and the shape of spectrum also there occurs change.
In addition, as shown in Figure 9, the luminescent spectrum of known embodiment 1 is compared with comparative example 1, and the migration of the peak of spectrum is little, even if the angle of visual field changes, also can form more identical shape.The change of shape of known spectra is relevant to the change of tone, and thus the migration amount of peak, spectral shape are all that a side with low uncertainty is more excellent.That is, known formation as embodiment 1 is except colourity change, also the briliancy that light takes out is improved because of the effect of light-transmitting layer.
Organic electric-field light-emitting element of the present invention has excellent light extraction efficiency, and the colourity corresponding relative to the position of organic electric-field light-emitting element with observer can be suppressed to change, therefore such as go in the various fields headed by display, computer, Vehicular display device, field display, domestic appliance, business machine, household electrical appliances machine, traffic related display, timepiece display, calendar date display, phosphor screen, sound machine etc.
Claims (9)
1. an organic electric-field light-emitting element, is characterized in that, is the organic electric-field light-emitting element at least successively with the first electrode, luminescent layer, the second semi-transmissive electrode, intermediate layer, semitransmissive layer and light-transmitting layer, and has:
The light penetrated from described luminescent layer is resonated and the first resonator structure penetrated between described first electrode and described second electrode; With
Described light is resonated and the second resonator structure penetrated between described first electrode and described semitransmissive layer,
Wherein, be set to t in 1/4 length of the peak wavelength by the light penetrated from described luminescent layer, when the refractive index of described light-transmitting layer is set to n, the thickness of described light-transmitting layer meets following formula: 0.9 × more than t/n, 1.1 × below t/n.
2. organic electric-field light-emitting element according to claim 1, is characterized in that, light-transmitting layer and and the layer that adjoins of this light-transmitting layer between specific refractivity be at least 0.1.
3. organic electric-field light-emitting element according to claim 1, is characterized in that, the material of semitransmissive layer is metal.
4. organic electric-field light-emitting element according to claim 3, is characterized in that, metal is selected from least one metal in silver, magnesium-silver alloy and aluminium.
5. organic electric-field light-emitting element according to claim 1, is characterized in that, luminescent layer contains the phosphorescent material of at least one.
6. organic electric-field light-emitting element according to claim 1, is characterized in that, organic electric-field light-emitting element is bottom emitting type.
7. organic electric-field light-emitting element according to claim 1, is characterized in that, between the second electrode and intermediate layer, also have light-transmitting layer,
Wherein, be set to t in 1/4 length of the peak wavelength by the light penetrated from described luminescent layer, when the refractive index of described light-transmitting layer is set to n, the thickness of described light-transmitting layer meets following formula: 0.9 × more than t/n, 1.1 × below t/n.
8. organic electric-field light-emitting element according to claim 1, is characterized in that,
In the luminescent spectrum of the luminescent material in luminescent layer, front resonant wavelength is shorter than first peak wavelengths several from the short wavelength side of luminescent spectrum,
Described luminescent spectrum meets the relation of the Δ λ < 25nm represented with following mathematical expression 1,
< mathematical expression 1>
Δλ＝λ(I0)-λ(0.2×I0)
Wherein, in described mathematical expression 1, λ (I0) represents front resonant wavelength, I0 represents the luminous intensity under this wavelength, λ (0.2 × I0) represents wavelength when reaching the luminous intensity of 0.2 times of the luminous intensity of λ (I0), λ (I0) > λ (0.2 × I0).
9. an organic electric field luminescent display, is characterized in that,
There is the redness using following organic electric-field light-emitting element as sub-pixel, green, blue each single pixel,
Described organic electric-field light-emitting element is the organic electric-field light-emitting element at least successively with the first electrode, luminescent layer, the second semi-transmissive electrode, intermediate layer, semitransmissive layer and light-transmitting layer, and has:
The light penetrated from described luminescent layer is resonated and the first resonator structure penetrated between described first electrode and described second electrode; And described light is resonated and the second resonator structure penetrated between described first electrode and described semitransmissive layer,
Wherein, be set to t in 1/4 length of the peak wavelength by the light penetrated from described luminescent layer, when the refractive index of described light-transmitting layer is set to n, the thickness of described light-transmitting layer meets following formula: 0.9 × more than t/n, 1.1 × below t/n.
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| KR102089330B1 (en) * | 2013-10-28 | 2020-03-17 | 엘지디스플레이 주식회사 | Organic Emitting Device and Organic Emitting Display Device Using the Same |
| KR102215147B1 (en) * | 2014-08-14 | 2021-02-15 | 삼성디스플레이 주식회사 | Organic light emitting diode display |
| KR102231631B1 (en) | 2014-10-08 | 2021-03-24 | 삼성디스플레이 주식회사 | Organic light emitting diode display |
| JP2018073761A (en) | 2016-11-04 | 2018-05-10 | パイオニア株式会社 | Light emitting device |
| CN109659443B (en) | 2017-10-10 | 2024-03-22 | 京东方科技集团股份有限公司 | Display panel, display device and method for improving color cast of display panel |
| CN110571244B (en) * | 2019-08-13 | 2022-07-12 | 深圳市华星光电半导体显示技术有限公司 | Display panel |
| CN112582561A (en) * | 2019-09-30 | 2021-03-30 | 株式会社日本有机雷特显示器 | Light emitting element, self-luminous panel, and method for manufacturing self-luminous panel |
| JP2021179495A (en) * | 2020-05-12 | 2021-11-18 | セイコーエプソン株式会社 | Electrooptical device and electronic apparatus |
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| US6406801B1 (en) * | 1998-02-04 | 2002-06-18 | Kabushiki Kaisha Toyota Chuo Kenkyusho | Optical resonator type organic electroluminescent element |
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