WO2006033492A1 - Dispositif organique electroluminescent blanc utilisant trois couches d'emission - Google Patents

Dispositif organique electroluminescent blanc utilisant trois couches d'emission Download PDF

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WO2006033492A1
WO2006033492A1 PCT/KR2004/002438 KR2004002438W WO2006033492A1 WO 2006033492 A1 WO2006033492 A1 WO 2006033492A1 KR 2004002438 W KR2004002438 W KR 2004002438W WO 2006033492 A1 WO2006033492 A1 WO 2006033492A1
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layer
emission
layers
emission layer
bis
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PCT/KR2004/002438
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English (en)
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Jong-Wook Park
Ho-Cheol Park
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Doosan Corporation
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Priority to PCT/KR2004/002438 priority Critical patent/WO2006033492A1/fr
Priority to JP2007533387A priority patent/JP4782791B2/ja
Publication of WO2006033492A1 publication Critical patent/WO2006033492A1/fr

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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
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H10K50/125—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers specially adapted for multicolour light emission, e.g. for emitting white light
    • 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
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/18—Carrier blocking layers
    • 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
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/18—Carrier blocking layers
    • H10K50/181—Electron blocking layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/30—Coordination compounds
    • H10K85/341—Transition metal complexes, e.g. Ru(II)polypyridine complexes
    • H10K85/342—Transition metal complexes, e.g. Ru(II)polypyridine complexes comprising iridium
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/30—Coordination compounds
    • H10K85/341—Transition metal complexes, e.g. Ru(II)polypyridine complexes
    • H10K85/346—Transition metal complexes, e.g. Ru(II)polypyridine complexes comprising platinum
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/60—Organic compounds having low molecular weight
    • H10K85/615—Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
    • H10K85/622—Polycyclic condensed aromatic hydrocarbons, e.g. anthracene containing four rings, e.g. pyrene
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/60—Organic compounds having low molecular weight
    • H10K85/631—Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/60—Organic compounds having low molecular weight
    • H10K85/649—Aromatic compounds comprising a hetero atom
    • H10K85/653—Aromatic compounds comprising a hetero atom comprising only oxygen as heteroatom
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/60—Organic compounds having low molecular weight
    • H10K85/649—Aromatic compounds comprising a hetero atom
    • H10K85/657—Polycyclic condensed heteroaromatic hydrocarbons

Definitions

  • the present invention relates to organic light emitting devices (OLEDs), and more particularly to white OLEDs using three emission layers to make white light.
  • OLEDs Organic light emitting devices
  • OLEDs show improved brightness and driving voltage, good response speed, and possibility of multi-colors compared to inorganic light emitting devices, because the OLEDs utilize organic materials for the light emission layer and can self-emit.
  • the OLEDs show good color reproduction when they are applied to a color display.
  • the OLEDs are suitable for portable information communication displays due to their many advantages such as thinness, compactness, and light weight.
  • a white OLED having a blue and a red light emission layers has a structure of FIG. 1.
  • An anode 1 is deposited on a substrate, and a hole i transporting and blue emission layer 10, a hole blocking and red emission layer 11 , an electron transporting layer 12, and a cathode 9 are successively deposited on the anode 1.
  • a hole transporting and blue emission layer 13, a red emission layer 14, a hole blocking layer 15, an electron transporting layer 16, and a cathode 9 are successively deposited on the anode 1 to obtain white light emission.
  • FIG. 2 shows an energy level diagram of a conventional white OLED having three emission layers.
  • An anode 1 is deposited as a bottom layer.
  • a red emission layer 21 are successively deposited on the anode 1 , and then an electron transporting layer 22 and a cathode 9 are deposited thereon.
  • the OLED having such a structure generates a white light by the following principle.
  • the OLED operating in the above-mentioned manner also has a difficulty in adjusting the purity degree of white light because it is not easy to control the amount of excitons that contribute to the RGB emission, and has a low emission efficiency.
  • the blue emission layer needs to be located closer to the anode 1 than the green emission layer 20 and the red emission layer 21 in view of the energy level.
  • the present invention provides an OLED having a white balancing layer and an exciton confinement structure.
  • the present invention provides an organic light emitting device comprising: an anode; a hole injecting layer formed on the anode; a hole transporting layer formed on the hole injecting layer; a plurality of light emission layers formed on the hole transporting layer; at least one organic material layer formed between two predetermined layers of the plurality of light emission layers and having an electron blocking effect; an electron transporting layer formed on the light emission layers; and a cathode formed on the electron transporting layer.
  • At least one of the plurality of light emission layers preferably has a low energy level compared with two layers adjacent to both its sides to form an exciton confinement structure.
  • a green emission layer, a red emission layer, and a blue emission layer are preferably included in the plurality of light emission layers, and the green emission layer is located between the hole transporting layer and the red emission layer to form an exciton confinement structure.
  • a green emission layer, a red emission layer, and a blue emission layer are preferably included in the plurality of light emission layers and at least one organic material layer having an electron blocking effect is formed between the red emission layer and the blue emission layer.
  • At least one of the hole transporting layer, the plurality of light emission layers, and the electron transporting layer may include a dopant of 0.1 to 5.0wt.%.
  • the dopant includes at least one of coumarin 6, rubrene, A- (dicyanomethylene)-2-methyl-6-(P- dimethylaminostyryl)-4H-pyran DCM), A- (dicyanomethylene)-2-t-butyl-6-(1 ,1 ,7,7,-tetramethyljulolidyl-9-enyl)- 4H-pyran (DCJTB), perylene, quinacridone, DCM2, 2,3,7,8,12,13,17,18-octaethyl-21 H, 23H- porphine platinum (PtOEP), and iridium(IH)bis[(4,6-difluoropheny)- pyridinato-N,C2']picolinate (Firpic), wherein PtOEP and Firpic are phosphorescent dopants.
  • the green emission layer, the red emission layer, and the blue emission layer may have thicknesses within the range of 100A to 500A, respectively.
  • the green emission layer includes aluminum tris (8- hydroxyquinoline) as a main material
  • the red emission layer includes at least one of [N,N'-bis(naphthalene-1-yl)phenyl]-N,N'-bis(phenyl)benzidine (NPB) and 4,4'-bis(carbazol-9-yl)biphenyl (CBP) which is phosphorescent host as a main material
  • the blue emission layer includes at least one of 4,4'- bis(2,2-diphenyl-ethen-1-yl)-diphenyl (DPVBi), 4,4"-bis (2,2-diphenylvinyl-1- yl)-p-terphenylene (DPVTP), and spiro-DPVBi as a main material.
  • the hole injecting layer may have a thickness of 400A to 1500A, and the hole transporting layer may have a thickness of 100A to 500A.
  • the hole injecting layer and the hole transporting layer may include at least one of 4,4',4"-tris[N-3-methylphenyl-N-phenyl-amino]-triphenylamine (m- MTDATA) and N,N'-bis(naphthalene-1-yl)-N,N'-bis(phenyl)benzidine (NPB) as a main material.
  • the electron transporting layer may have a thickness within 100A to
  • the anode may have a thickness within 1.000A to 2,000 A and is made of at least one of indium-tin-oxide(ITO), SnO 2 ,and ZnO.
  • the cathode may have a thickness within 500A to 5,00OA and is made of at least one of Li, LiF, Mg, Al, Al-Li, Ca, Mg-In, and Mg-Ag.
  • the cathode may have a double-layered structure including a LiF layer having a thickness within 5 A to 20 A and an Al layer having a thickness within 1 ,000A to 2,00OA.
  • a green emission layer, a red emission layer, and a blue emission layer may be included in the plurality of light emission layers, and further comprised is an emission reinforcing layer for enhancing emission efficiency between the blue emission layer and the electron transporting layer, the emission reinforcing layer including a blue emission layer, and at least one of a n-type layer and a p-type layer.
  • the present invention provides an organic light emitting device comprising: an anode; a hole injecting layer formed on the anode; a hole transporting layer formed on the hole injecting layer; a plurality of light emission layers formed on the hole transporting layer; an electron transporting layer formed on the light emission layers; and a cathode formed on the electron transporting layer, wherein at least one of the plurality of light emission layers has a low energy level compared with two layers adjacent to both its sides to form an exciton blocking structure.
  • the device may further comprises at least one organic material layer having an electron blocking effect and interposed between two predetermined layers of the plurality of light emission layers.
  • FIG. 1 is a diagram showing the energy level structure of a conventional white OLED having only a blue and a red emission layer.
  • FIG. 2 is a diagram showing the energy level structure of a conventional white OLED having three emission layers.
  • FIG. 3A is a cross-sectional view showing a layer structure of a white OLED according to an embodiment of the present invention.
  • FIG. 3B is a diagram showing an energy level structure of a white
  • OLED according to an embodiment of the present invention.
  • FIG. 4 is a diagram showing an energy level structure of a white OLED according to another embodiment of the present invention.
  • FIG. 5 is a diagram showing an energy level structure of a white OLED according to still another embodiment of the present invention.
  • FIGs. 6 to 8 show light emission spectra of white OLEDs according to the several embodiments of the present invention.
  • FIGs. 9 and 10 show light emission spectra, color coordinates, and efficiency characteristics of white OLEDs of two comparative embodiments. Detailed Description of the Preferred Embodiments
  • FIG. 3A is a cross sectional view showing a layer structure of a white OLED according to an embodiment of the present invention
  • FIG. 3B is a diagram showing an energy level structure of a white OLED according to an embodiment of the present invention.
  • the white OLED includes an insulating substrate 100 and an anode 1 , a hole injecting layer 2, a hole transporting layer 3, a green emission layer 4, a red emission layer 5, a white balancing layer 6, a blue emission layer 7, an electron transporting layer 8, and a cathode 9 successively deposited on the insulating substrate 100.
  • the white balancing layer 6 effectively blocks movement of electrons which are introduced through the cathode 9, the electron transporting layer 8, and the blue emission layer 7 to control the emission ratio of R, G, and B.
  • the green emission layer 4 has a lower LUMO (lowest unoccupied molecular orbital) than those of the hole transporting layer 3 and red emission layer 5 respectively adjacent to both its sides, an exciton confinement structure 17 is formed, so that the green emission efficiency is enhanced.
  • at least one or more of the hole transporting layer 3, the emission layers 4, 5, and 7, and the electron transporting layer 8 include dopants enabling the layers 4, 5, and 7 to emit light through the hole- electron combination.
  • perylene, quinacridone, or (2-metyle-6-(2-(2,3,6,7-tetrahydro-1 H, 5H-benzo quinolizin-9-yl)ethenyl)-4H- pyran-4-ylidene)propane-dinitrile (DCM2), etc. may be applied as the dopants.
  • a phosphorescent dopant 2,3,7,8,12, 13,17,18-octaethyl-21 H or 23H-porphine platinum (PtOEP) may be used for red light, and iridium( ⁇ i)bis[(4,6-di-fluoropheny)-pyridinato-N,C2 1 ]picolinate (Firpic), etc. may be used for blue light.
  • the amount of dopant is 1 ⁇ 20 wt.% of that of the host materials of the hole transporting layer 3, the emission layers 4, 5, and 7, and the electron transporting layer 8.
  • the above described dopants have the following chemical formulas.
  • Host materials for forming the emission layers 4, 5, and 7 are as follows.
  • the host material of the green emission layer 4 is aluminum tris(8- hydroxyquinoline).
  • the host material of the red and/or yellow emission layer 5 is one of [N,N'-bis(naphthalene-1-yl)phenyl]-N,N'-bis(phenyl)benzidine (NPB) and 4,4'-bis(carbazol-9-yl)biphenyl (CBP), which are phosphorescent hosts.
  • the host material of the blue emission layer 7 is 4,4'-bis(2,2-diphenyl-ethen-1 - yl)-diphenyl (DPVBi).
  • DPVTP 4,4"-bis (2,2-diphenylvinyl-1-yl)-p-terphenylene
  • spiro-DPVBi etc. which are low molecular materials may also be used as the host material of the blue emission layer 7,.
  • DPVBi 4,4"-bis (2,2-diphenylvinyl-1-yl)-p-terphenylene
  • the emission layers 4, 5, and 7 are formed by adding the above dopant materials.
  • the emission layers 4, 5, and 7 have thicknesses within the range of 100 A to 200A in accordance with the degree of contribution to generation of the white light, and the range of the thickness may be changed depending on characteristics of the materials used.
  • Materials suitable for the hole injecting layer 2 and the hole transporting layer 3 have triphenyl amine radicals having hole-transporting characteristics.
  • triphenyl amine radicals having hole-transporting characteristics.
  • m-MTDATA 4,4',4"-tris[N-3-methylphenyl-N-phenyl-amino]- triphenylamine
  • NPB N,N'-bis(naphthalene-1-yl)-N,N'- bis(phenyl)benzidine
  • the above materials have the following chemical formulas.
  • the hole injecting layer 2 formed on the anode 1 has a thickness within the range of 400A to 1 ,50OA, and that the hole transporting layer 3 has a thickness within the range of 100A to 500A.
  • the OLED includes the insulating substrate 100 which is generally used for typical OLEDs.
  • the substrate is a glass substrate or a transparent plastic substrate having good transparency, a very flat surface, ease of handling, and a good waterproof characteristic.
  • the anode 1 is formed of a material having outstanding transparency and conductivity such as indium-tin-oxide (ITO), SnO 2 , ZnO, etc., to have a thickness within the range of 1 ,000 A to 2,000 A.
  • ITO indium-tin-oxide
  • SnO 2 SnO 2
  • ZnO ZnO
  • the cathode 9 is formed of a metal such as Li, Mg, Al, Al-Li, Ca, Mg-In, Mg-Ag, etc., to have a thickness within the range of 1 ,000 A to 2,000 A.
  • the cathode 9 is preferably formed of a LiF layer having high reactivity, a low work function, and a thickness within the range of 5 A to 20 A, and an Al layer deposited on the LiF layer and having a high work function and a thickness within the range of 5,00 A to 5,00OA.
  • a double-layered structure is preferable for stability and efficiency of the device.
  • the electron transporting layer 8 is formed of an electron transporting material such as tris(8-quinolinolate)-aluminum (Alq3) to have a thickness within the range of 100 A to 1 ,00OA.
  • Alq3 tris(8-quinolinolate)-aluminum
  • FIG. 3B is a diagram showing the energy level structure of a white
  • the white balancing layer 6 having an electron blocking effect is interposed between the red emission layer 5 and the blue emission layer 7, and the green emission layer 4 having low LUMO level is interposed between the hole transporting layer 3 and the red emission layer 5 to form a quantum well that is the exciton confinement structure 17.
  • desirable thickness of the white balancing layer 6 is within the range of 10 A to 3OA depending on the contribution degree to generating white light.
  • the green emission layer 4 must be interposed between the hole transporting layer 3 and the red emission layer 5 to form a well-shaped energy level structure.
  • the white OLED has the successively disposed structure as follows: the anode; the hole injecting layer; the hole transporting layer; the green emission layer; the red emission layer; the white balancing layer; the blue emission layer; the electron transporting layer; and the cathode, wherein the red emission layer can be replaced by a yellow emission layer.
  • the device can be formed in the order of the anode, the hole injecting layer, the hole transporting layer, the green emission layer, the white balancing layer, the red emission layer, the blue emission layer, the electron transporting layer, and the cathode.
  • the device may further includes an emission reinforcing layer 23 between the blue emission layer 7 and the electron transporting layer 8 to enhance emission efficiency of the blue emission layer 7.
  • the emission reinforcing layer 23 has a multi-layered structure such as a blue emission layer/n-type layer, a blue emission layer/p-type layer, and a blue emission layer/n-type layer/p-type layer.
  • the excitons generated during the device operation are controlled to distribute properly in accordance with each contribution degree of the R, G, and B emission layers 5, 4, and 7 to generating white light by the white balancing layer 6. Accordingly, the maximum emission efficiency of each color can be obtained without serious reliance upon the structure of the R, G, and B layers such as concentration of the dopants and thickness of the emission layers.
  • a conventional white OLED generates white light by inducing light emission at the interface and on the bulk of the hole transporting layers 10 and 13 and the emission layers 11 and 14 through hole blocking effect of the hole blocking layer 10 and 15.
  • the white balancing layer 6 controls the electron distribution through the electron blocking effect to enables the unused excitons in the blue emission layer 7 to contribute to the red emission layer 5 and the green emission layer 4.
  • HBL hole blocking layer
  • some structural limitations are unavoidable to satisfy the emission mechanism in the aspect of energy level.
  • the blue emission layers 10 and 13 must be disposed closer to the anode 1 than the red emission layers 11 , 14, and 21.
  • the exciton blocking structure 17 of the present invention is proposed to solve a typically known problem in the field of OLEDs that the green light emission is softly generated when the green emission layer 4 is deposed in the front of the anode 1.
  • This exciton blocking structure 17 prevents such a problem to enable generating white light comprising balanced three balanced kinds of light (R, G, and B).
  • the exciton blocking effect may be obtained by the exciton blocking structure 17 that is a quantum well in which the excitons introduced to the green emission layer 4 are thrown and confined. Accordingly, the lower contribution of the green emission can be solved, which is a problem that is not only typical with an HBL using emission device but is typical to a white OLED that obtains white light by three emission layers. Moreover, since the surplus excitons unused for blue and red emission participate in only green emission through the above mentioned quantum well structure, it is benificial to prevent contribution without light emission to the anode 1 which is a cause of life reduction of the device.
  • ITO indium tin oxide
  • m- MTDTA is deposited by vacuum deposition to form a hole injecting layer 2 having a thickness of 400A.
  • a hole transporting layer 3 having a thickness of 100 A is formed by vacuum deposition of NPB on the hole injecting layer 2.
  • a green emission layer 4 having a thickness of 180A is formed by vacuum deposition of AIq 3 and coumarin 6 on the hole transporting layer 3. In this step, both materials are deposited at the same time, and the green emission layer 4 has 99wt.% of Alq3 and 1.0wt.% of coumarin 6.
  • a 120A red emission layer 5 is formed by vacuum deposition of NPB and DCM.
  • NPB and DCM are deposited at the same time in the similar manner with the deposition of the green emission layer 4.
  • the red emission layer 5 has 96wt.% of NPB and the 4.0wt.% of DCM.
  • a white balancing layer 6 capable of controlling the exciton distribution is formed by NPB vacuum deposition.
  • the white balancing layer 6 has a thickness of 17 A.
  • a blue emission layer 7 is formed on the white balancing layer 6 by vacuum deposition of DPVBi, and an electron transporting layer 8 is formed by vacuum deposition of AIq 3 on the blue emission layer 7.
  • the blue emission layer 7 has a thickness of 180A and the electron transporting layer 8 has a thickness of 120 A.
  • a LiF layer which is an electron injecting layer is deposited on the electron transporting layer 8 to have thickness of 10A, then an Al layer is deposited on the LiF layer to have a thickness of 2,000 A to form a cathode 9.
  • the electron blocking effect can be expected by forming the white balancing layer 6 between the red emission layer 5 and the blue emission layer 7. Due to this effect, one portion of electrons contributes to light emission at the DPVBi doped blue emission layer 7, another portion of electrons contributes to emission of orange-red light at the DCM doped red emission layer 5, and the other portion contributes to emission of the green light at the coumarin-doped green emission layer 4.
  • FIG. 6 shows a light emission spectrum, color coordinates, and efficiency characteristics of a white OLED according to the first embodiment of the present invention.
  • each R, G, and B lights evenly contributes to generating white light and respectively has peaks near 455 ran, 510 ran, and 590 ran.
  • the emitted white light has a color coordinate position of (0.33, 0.38) and has the emission efficiency of 6.1cd/A, 2.31 m/W.
  • the second embodiment When the second embodiment is compared with the first embodiment, the second embodiment has the following two peculiar features that are different from the first embodiment.
  • NPB and rubrene are simultaneously deposited under a vacuum to form the red emission layer 5 that includes 97wt.% of NPB and 3wt.% of rubrene.
  • the white balancing layer 6 has a thickness of 19 A to tune the purity degree of color.
  • one portion of the excitons contributes to yellow-orange emission in rubrene of the red emission layer 5, while the other portion of the excitons contributes to blue and green emission to tune the purity degree of color by controlling thickness variation of the white balancing layer 6.
  • FIG. 7 shows the light emission spectrum, color coordinates, and efficiency characteristics of the second embodiment of white OLEDs according to the present invention.
  • the emission spectrum of FIG.7 all three colors of R, G, and B contribute to white light emission, and each of the colors respectively has the maximum wavelength peak of 455 nm, 511 nm, and 560 run.
  • the emitted white light has a color coordinate position of (0.28, 0.36) and has an emission efficiency of 6.8cd/A, 2.51 m/W.
  • the second and third embodiments are similar in the procedure except that, in the third embodiment, the thickness of the white balancing layer 6 is formed to have thickness of 17 A.
  • the white balancing layer 6 controls the distribution of electrons which effects light emission. That is, the white balancing layer 6 controls the distribution of excitons. For example, if the thickness of the white balancing layer 6 formed between the red emission layer 5 and the blue emission layer 7 is reduced, contribution of the blue emission layer 7 to white light emission is also reduced due to the reduction of electron blocking effect, while contribution of the green emission layer 4 and the red emission layer 5 is increased. Since the contributions of the green and yellow are increased, the color coordinate position of the white light moves toward the place of the long wavelength.
  • FIG. 8 shows a light emission spectrum, chromaticity coordinates, and efficiency characteristics of a white OLED according to a third embodiment of the present invention.
  • the emission spectrum of FIG. 8 thoroughly supports the above illustration, and in this case, the emitted white light has a color coordinate position of (0.31 , 0.40) and has an emission efficiency of 7.1 cd/A, 2.31 m/W.
  • an OLED without the exciton blocking structure is prepared and its characteristics are illustrated hereinafter.
  • ITO indium tin oxide
  • m-MTDTA is deposited by vacuum deposition to form a hole injecting layer of 400 A.
  • a hole transporting layer of 100A is formed by vacuum deposition of NPB on the hole injecting layer.
  • a green emission layer of 140 A is prepared by vacuum deposition of
  • a white balancing layer for controlling the distribution of excitons is formed to have thickness of 17 A on the blue emission layer, and a red emission layer of 120A is prepared by vacuum deposition of AIq 3 and coumarin at the same time.
  • the red emission layer has 99wt,% Alq3 and 1.0wt.% coumarin.
  • a blue emission layer of 180A is formed on the red emission layer by DPVBi vacuum deposition.
  • an electron transporting layer of 150A is formed on the blue emission layer, and a LiF electron injecting layer of 10 A and a Al electrode of
  • FIG. 9 shows a light emission spectrum, color coordinates, and efficiency characteristics of a white OLED according to the first comparative embodiment of the present invention.
  • the emitted light has a color coordinate position of (0.37, 0.54) and is a shallow yellow light.
  • ITO indium tin oxide
  • m-MTDTA is deposited by vacuum deposition to form a hole injecting layer of 370A.
  • a hole transporting layer of 100A is formed by vacuum deposition of NPB on the hole injecting layer.
  • a green emission layer and a red emission layer are deposited without the white balancing layer.
  • the green emission layer has 97wt.% of NPB and 3.0wt.% of rubrene, and the red emission layer is prepared by DPVBi vacuum deposition to have a thickness of 200A.
  • an electron transporting layer of 160 A is deposited and a LiF electron injecting layer is successively deposited on the electron transporting layer by LiF vacuum deposition to have thickness of 10A.
  • an Al electrode of 200 A is deposited by Al vacuum deposition.
  • Figure 10 shows the light emission spectrum, color coordinates, and efficiency characteristics of the second comparative embodiment of white
  • OLEDs according to the present invention.
  • all excitons are distributed over the green emission layer of rubrene, making the yellow light emission. That is, because there is no white balancing layer capable of making the blue light emission in accordance with the electron blocking effect, the blue light emission cannot be expected. Accordingly, the emitted light has a color coordinate position of (0.46, 0.47).
  • characteristics of brightness efficiency, maximum brightness, quantum efficiency, and color coordinates of the first, second, and third embodiments and the first and second comparative embodiments according to the present invention are charted in Table 1.
  • the OLEDs of the first to third embodiments with the exciton blocking structure and the white balancing 0 layer are more suitable than the OLEDs of the first and second comparative experiments without either the exciton blocking structure or the white balancing layer in view of contribution of three-color emission to the white light emission.
  • the OLEDs of the present invention include the white balancing layer 5 that enables controlling the exciton distribution, and include the exciton blocking structure that enables generating white light including a balanced amount of RGB.
  • the purity degree of color of emitted light is easily adjusted and light emitting efficiency of the device can be extremely enhanced by using the maximum emission efficiency of the plurality of emission layers. Since white light containing all three colors is generated, a color display can be manufactured by using color filters.

Abstract

L'invention concerne des dispositifs organiques électroluminescents blancs comportant un substrat, une anode, une couche d'injection de trous, une couche de transport de trous, des couches d'émission rouge, verte et bleue, une couche d'équilibrage des blancs, une couche de transport d'électrons et une cathode posée sur le substrat. Dans cette structure, étant donné qu'il est possible de maîtriser le rapport d'émission des couches d'émission trichrome, les excitons, qui ne contribuent pas à l'émission de la lumière bleue, participent à l'émission des lumière jaune ou rouge. L'émission de la lumière verte est renforcée par un effet de confinement d'excitons. En conséquence, toutes les couches trichromes contribuent à la création de la lumière blanche avec une grande efficacité. En outre, l'utilisation de la couche d'équilibrage des blancs permet de maîtriser le rapport d'émission de la pluralité de couches d'émission afin de renforcer l'efficacité de l'émission de la lumière blanche.
PCT/KR2004/002438 2004-09-22 2004-09-22 Dispositif organique electroluminescent blanc utilisant trois couches d'emission WO2006033492A1 (fr)

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PCT/KR2004/002438 WO2006033492A1 (fr) 2004-09-22 2004-09-22 Dispositif organique electroluminescent blanc utilisant trois couches d'emission
JP2007533387A JP4782791B2 (ja) 2004-09-22 2004-09-22 三原色光を利用する白色有機電界発光素子

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006202747A (ja) * 2005-01-20 2006-08-03 Samsung Sdi Co Ltd 有機電界発光素子及びその製造方法
EP1862524A1 (fr) * 2006-05-29 2007-12-05 Samsung SDI Co., Ltd. Dispositif électroluminescent organique et dispositif d'affichage à écran plat le comprenant
JP2008108709A (ja) * 2006-09-28 2008-05-08 Fujifilm Corp 有機発光素子
FR2912553A1 (fr) * 2007-06-12 2008-08-15 Thomson Licensing Sas Diode organique electroluminescente comprenant une pluralite de couches electroluminescentes empilees
EP2133932A1 (fr) * 2007-03-23 2009-12-16 Idemitsu Kosan Co., Ltd. Dispositif électroluminescent organique
US8021764B2 (en) 2004-11-29 2011-09-20 Samsung Mobile Display Co., Ltd. Phenylcarbazole-based compound and organic electroluminescent device employing the same
US8021765B2 (en) 2004-11-29 2011-09-20 Samsung Mobile Display Co., Ltd. Phenylcarbazole-based compound and organic electroluminescent device employing the same
US8188315B2 (en) 2004-04-02 2012-05-29 Samsung Mobile Display Co., Ltd. Organic light emitting device and flat panel display device comprising the same
US8394511B2 (en) 2008-02-11 2013-03-12 Samsung Display Co., Ltd. Compound for forming organic film, and organic light emitting device and flat panel display device including the same
CN108808449A (zh) * 2018-06-22 2018-11-13 南京邮电大学 一种基于三线态激子放大器的有机激光薄膜器件及应用

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6023073A (en) * 1995-11-28 2000-02-08 International Business Machines Corp. Organic/inorganic alloys used to improve organic electroluminescent devices
US6285039B1 (en) * 1996-08-19 2001-09-04 Tdk Corporation Organic electroluminescent device
US6433355B1 (en) * 1996-06-05 2002-08-13 International Business Machines Corporation Non-degenerate wide bandgap semiconductors as injection layers and/or contact electrodes for organic electroluminescent devices
US6613454B2 (en) * 2000-04-21 2003-09-02 Tdk Corporation Organic EL device

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000196140A (ja) * 1998-12-28 2000-07-14 Sharp Corp 有機エレクトロルミネッセンス素子とその製造法
JP4329305B2 (ja) * 2001-08-27 2009-09-09 株式会社デンソー 有機ｅｌ素子
JP2005100921A (ja) * 2003-08-22 2005-04-14 Sony Corp 有機ｅｌ素子および表示装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6023073A (en) * 1995-11-28 2000-02-08 International Business Machines Corp. Organic/inorganic alloys used to improve organic electroluminescent devices
US6433355B1 (en) * 1996-06-05 2002-08-13 International Business Machines Corporation Non-degenerate wide bandgap semiconductors as injection layers and/or contact electrodes for organic electroluminescent devices
US6285039B1 (en) * 1996-08-19 2001-09-04 Tdk Corporation Organic electroluminescent device
US6613454B2 (en) * 2000-04-21 2003-09-02 Tdk Corporation Organic EL device

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9478754B2 (en) 2004-04-02 2016-10-25 Samsung Display Co., Ltd. Phenylcarbazole-based compounds and fluorene-based compounds and organic light emitting device and flat panel display device comprising the same
US9917258B2 (en) 2004-04-02 2018-03-13 Samsung Display Co., Ltd. Phenylcarbazole-based compounds and fluorene-based compounds and organic light emitting device and flat panel display device comprising the same
US8188315B2 (en) 2004-04-02 2012-05-29 Samsung Mobile Display Co., Ltd. Organic light emitting device and flat panel display device comprising the same
US11482678B2 (en) 2004-04-02 2022-10-25 Samsung Display Co., Ltd. Phenylcarbazole-based compounds and fluorene-based compounds and organic light emitting device and flat panel display device comprising the same
US10573821B2 (en) 2004-04-02 2020-02-25 Samsung Display Co., Ltd. Phenylcarbazole-based compounds and fluorene-based compounds and organic light emitting device and flat panel display device comprising the same
US10211406B2 (en) 2004-04-02 2019-02-19 Samsung Display Co., Ltd. Phenylcarbazole-based compounds and fluorene-based compounds and organic light emitting device and flat panel display device comprising the same
US8974922B2 (en) 2004-04-02 2015-03-10 Samsung Display Co., Ltd. Phenylcarbazole-based compounds and fluorene-based compounds and organic light emitting device and flat panel display device comprising the same
US11950501B2 (en) 2004-04-02 2024-04-02 Samsung Display Co., Ltd. Phenylcarbazole-based compounds and fluorene-based compounds and organic light emitting device and flat panel display device comprising the same
US8021765B2 (en) 2004-11-29 2011-09-20 Samsung Mobile Display Co., Ltd. Phenylcarbazole-based compound and organic electroluminescent device employing the same
US8021764B2 (en) 2004-11-29 2011-09-20 Samsung Mobile Display Co., Ltd. Phenylcarbazole-based compound and organic electroluminescent device employing the same
JP2006202747A (ja) * 2005-01-20 2006-08-03 Samsung Sdi Co Ltd 有機電界発光素子及びその製造方法
EP1862524A1 (fr) * 2006-05-29 2007-12-05 Samsung SDI Co., Ltd. Dispositif électroluminescent organique et dispositif d'affichage à écran plat le comprenant
JP2008108709A (ja) * 2006-09-28 2008-05-08 Fujifilm Corp 有機発光素子
EP2133932A4 (fr) * 2007-03-23 2011-06-22 Idemitsu Kosan Co Dispositif électroluminescent organique
EP2133932A1 (fr) * 2007-03-23 2009-12-16 Idemitsu Kosan Co., Ltd. Dispositif électroluminescent organique
US8207526B2 (en) 2007-03-23 2012-06-26 Idemitsu Kosan Co., Ltd. Organic EL device
FR2912553A1 (fr) * 2007-06-12 2008-08-15 Thomson Licensing Sas Diode organique electroluminescente comprenant une pluralite de couches electroluminescentes empilees
US8394511B2 (en) 2008-02-11 2013-03-12 Samsung Display Co., Ltd. Compound for forming organic film, and organic light emitting device and flat panel display device including the same
CN108808449A (zh) * 2018-06-22 2018-11-13 南京邮电大学 一种基于三线态激子放大器的有机激光薄膜器件及应用

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