WO2007071450A1 - Dispositif electronique a structure en couche faite de couches organiques - Google Patents

Dispositif electronique a structure en couche faite de couches organiques Download PDF

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WO2007071450A1
WO2007071450A1 PCT/EP2006/012516 EP2006012516W WO2007071450A1 WO 2007071450 A1 WO2007071450 A1 WO 2007071450A1 EP 2006012516 W EP2006012516 W EP 2006012516W WO 2007071450 A1 WO2007071450 A1 WO 2007071450A1
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type doped
organic
layer
electronic device
doped
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PCT/EP2006/012516
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English (en)
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Sven Murano
Jan Birnstock
Ansgar Werner
Markus Burghart
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Novaled Ag
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Priority claimed from EP06001231A external-priority patent/EP1804309B1/fr
Application filed by Novaled Ag filed Critical Novaled Ag
Priority to US12/158,479 priority Critical patent/US7830089B2/en
Priority to JP2008546288A priority patent/JP5583345B2/ja
Priority to KR1020087018120A priority patent/KR101460117B1/ko
Priority to CN2006800528745A priority patent/CN101375429B/zh
Publication of WO2007071450A1 publication Critical patent/WO2007071450A1/fr

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/30—Doping active layers, e.g. electron transporting 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]
    • H10K50/14—Carrier transporting layers
    • H10K50/15—Hole transporting layers
    • H10K50/155—Hole transporting layers comprising dopants
    • 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]
    • H10K50/14—Carrier transporting layers
    • H10K50/16—Electron transporting layers
    • H10K50/165—Electron transporting layers comprising dopants
    • 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]
    • H10K50/19—Tandem OLEDs
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2101/00—Properties of the organic materials covered by group H10K85/00
    • H10K2101/50—Oxidation-reduction potentials, e.g. excited state redox potentials
    • 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
    • H10K59/32—Stacked devices having two or more layers, each emitting at different wavelengths
    • 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
    • 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
    • H10K85/60—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
    • H10K85/633—Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine comprising polycyclic condensed aromatic hydrocarbons as substituents on the nitrogen atom
    • 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
    • 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
    • H10K85/6572—Polycyclic condensed heteroaromatic hydrocarbons comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole

Definitions

  • the invention refers to an electronic device comprising a layer structure of organic layers.
  • OLEDs organic light emitting diodes
  • p-n- diodes organic p-n- diodes
  • organic photovoltaic devices organic photovoltaic devices
  • Organic electroluminescent (EL) devices are becoming of increasing interest for applications in the field of displays or lighting sources.
  • Such organic light emitting devices or organic light emitting diodes are electronic devices, which emit light if an electric potential is applied.
  • the structure of such OLEDs comprises, in sequence, an anode, an organic electroluminescent medium and a cathode.
  • the electroluminescent medium which is positioned between the anode and the cathode, is commonly comprised of an organic hole-transporting layer (HTL) and an electron-transporting layer (ETL).
  • HTL organic hole-transporting layer
  • ETL electron-transporting layer
  • the light is then emitted near the interface between HTL and ETL where electrons and holes combine, forming excitons.
  • HTL organic hole-transporting layer
  • ETL electron-transporting layer
  • multilayer OLEDs which additionally contain a hole-injection layer (HIL), and / or an electron-injection layer (EIL), and / or a hole-blocking layer (HBL), and / or an electron-blocking layer (EBL), and or other types of interlayers between the EML and the HTL and / or ETL, respectively.
  • HIL hole-injection layer
  • EIL electron-injection layer
  • HBL hole-blocking layer
  • EBL electron-blocking layer
  • EBL electron-blocking layer
  • a further improvement of the OLED performance can be achieved by the use of doped charge carrier transport layers as disclosed in EP 0498979 Al .
  • the ETL is doped with an electron donor such as an alkali metal
  • the HTL is doped with an electron acceptor, such as F4-TCNQ.
  • This redox type doping is based on a charge transfer reaction between the dopant and the matrix, releasing electrons (in the case of n-type doping) or holes (in the case of p-type doping) onto the charge carrier transport matrix.
  • the dopants remain as charged species in the matrix, in the case of n-type doping the electron donors are positively charged, in the case of p-type doping the acceptor dopants are negatively charged.
  • OLEDs using doped charge carrier transport layers are commonly known as PIN-OLEDs. They feature extremely low operating voltages, often being close to the thermodynamical limit set by the wavelength of the emitted light.
  • One requirement for doped organic layers in OLEDs is that the excitons created within the emission zone have energies high enough to create visible light. The highest energy is needed for an emission in the blue range of the spectrum with a wavelength of 400 - 475 nm. To allow for such light emission, the electroluminescent material requires a sufficient band gap, which is about the energy of the emitted photons, or higher. It is desirable to choose the energy levels of the HTL and ETL carefully, such that the energy levels match with the emission zone to avoid additional barriers within the OLED device. The energy levels are frequently identified as HOMO (highest occupied molecular orbital) or LUMO (lowest unoccupied molecular orbital). They can be related to the oxidation potential or the reduction potential of the material, respectively.
  • HOMO highest occupied molecular orbital
  • LUMO lowest unoccupied molecular orbital
  • redox potentials of materials can be provided as a voltage value vs. Fc / Fc + .
  • Fc/Fc + denotes the ferrocene / ferrocenium reference couple.
  • Redox potentials can be measured for instance by cyclovoltammetry in a suitable solution, for instance acetonitrile or tetra- hydrofuran. Details of cyclovoltammetry and other methods to determine reduction potentials and the relation of the ferrocene/ferrocenium reference couple to various reference electrodes can be found in A. J. Bard et al., ,Electrochemical Methods: Fundamentals and Applications", Wiley, 2 nd edition 2000.
  • the energy levels of the acceptor or donor dopants are of importance, too. They can be similarly established by electrochemical methods.
  • An alternative measure for the oxidation strength of the donor dopant molecule or the HOMO level energy can be ultraviolet photoelectron spectroscopy (UPS).
  • UPS ultraviolet photoelectron spectroscopy
  • the ionization potential is determined. It has to be distinguished, whether the experiment is carried out in the gas-phase or in the solid phase, i.e. by investigation of a thin film of the material. In the latter case, solid-state effects such as the polarization energy of the hole remaining in the solid after removal of the photoelectron give rise to deviations in the ionization potential as compared to gas-phase value.
  • a typical value for the polarization energy is around 1 eV (E. V. Tsiper et al., Phys. Rev. B 195124/1-12(2001).
  • stacked or cascaded OLED structures have been proposed, in which several individual OLEDs are vertically stacked.
  • the improvement of the OLED performance in such stacked organic electroluminescent devices is generally attributed to an overall reduction of the operating current density combined with an increased operating voltage, as the individual OLEDs are connected in a row.
  • Such a design leads to lower stress of the organic layers, since the current injected and transported within the organic layers is reduced.
  • the stacking of several OLED units in one device allows a mixing of different colours in one device, for example in order to generate white light emitting devices.
  • non-conductive charge generation layers (with a resistivity of not less than 10 5 ⁇ cm) was disclosed in US2003/0189401 Al.
  • a significant drawback of the approach is the fact, that the organic layers forming the p-n-junction are doped using inorganic elements and molecules with a small atom count.
  • the stacked OLED devices are subject to a rapid breakdown during operation, most likely due to a dopant migration.
  • Some molecular organic dopants having a somewhat higher atom count such as F4-TCNQ are known in literature, which might be used for p-type doped organic charge transport layers instead of inorganic compounds; however this measure alone does not improve the stability of the stacked OLED devices.
  • n-type doping could only be achieved by doping organic layers with alkali or earth alkali metals, which act as electron donors within organic layers.
  • metal salts and metal compounds is described (WO 03 / 044829 Al)
  • the doping effect in these cases can only be attributed to a cleavage of the salts or compounds that release the metals in an uncharged state.
  • One example is the doping with Cs 2 CO 3 , an inorganic salt that upon heating decomposes to release oxygen, CO 2 and caesium metal.
  • N-type doping with metals in stacked devices that contain a p-n- interface being driven in reverse direction leads to a rapid breakdown due to metal migration at the junction.
  • an electronic device comprising a layer structure of organic layers according to claim 1 is provided.
  • molecular dopants With the use of molecular dopants, degradation mechanisms that occur in the case of doping with metals or small molecule dopants, can be minimized or even completely avoided.
  • molecular it is referred to inorganic or organic compounds that consist of more than six atoms within the dopant molecule. More favourable, the number of atoms forming the dopant molecules is larger than twenty.
  • the molecular dopants are organic or inorganic molecules, but may also be molecular salts, i.e. salts that consist of at least two charged molecular subunits forming a salt.
  • the molecular dopants might also be charge transfer complexes in which only a partial charge transfer between the constituting units occurs. In both cases at least one of the subunits forming the molecular salt or the molecular charge transfer complex also fulfils the above definition, namely an atom count of larger than six.
  • all the subunits forming the molecular salt or the molecular charge transfer complex fulfil the above definition, namely an atom count of larger than six.
  • the dopand molecule preferably does not comprise alkali metals since they are very prone to diffusion within the transport layers, which limits lifetime and thermal stability drastically.
  • a reduction potential of the p-type dopant is equal or larger than about 0 V vs. Fc / Fc +
  • an oxidation potential of the n-type dopant is equal or smaller than about -1.5 V vs. Fc / Fc + .
  • the reduction potential of the p-type dopant is equal or larger than about 0.18 V vs. Fc / Fc + , preferably equal or larger than about 0.24 V vs. Fc / Fc + .
  • the oxidation potential of the n- type dopant is equal or smaller than about -2.0 V vs. Fc / Fc + , preferably equal or smaller than about -2.2 V vs. Fc / Fc + .
  • An alternative measure for the oxidation strength of the donor dopant molecule can be ultra- violet photoelectron spectroscopy (UPS). If measured by means of this method, an ionization potential of the donor dopant is equal or lower than about 5.5 eV, preferably equal or lower than about 5 eV, preferably equal or lower than about 4.8 eV measured in the solid state. If measured in the gas phase, the ionization potential of the donor dopant is equal or lower than about 4.5 eV, preferably equal or lower than about 4 eV, more preferably equal or lower than about 3.8 eV. These values correspond to the onset of photoemission at the high kinetic energy side, i.e. the weakest bound photoelectrons.
  • the proposed p-n-junction is also beneficial for stacked organic photovoltaic devices, as the open circuit voltage might be increased to a maximum of n-times the photon energy.
  • Fur- thermore in current organic photovoltaic devices, only less than 50% of the incident light is absorbed in the photoactive layer. The stacking of photovoltaic devices thus allows harvesting of more than 50% of the incident light due to the presence of more than one photoactive layer in the stack.
  • Fermi-level of the n-doped layer is determined by the ionization potential of the donor dopant.
  • a backward bias or backward voltage is applied to a p-n-junction, if electrons are injected into the p-type doped transport layer from the electrode and holes are injected into the n-type doped transport layer from the other electrode. If the p-n-junction is not sandwiched between electrodes, a backward operation is given in the case, where the applied field is such, that electrons negative charges are moving from the p-type doped layer of the junction into the n- type doped layer of the junction and positive charges are moving in the opposite direction.
  • the fixation of dopants is preferably ensured by the high molecular weight of the dopant (> 300 g / mol) as well as the high atomic count of the compounds, preventing it from a migration into the n- type or p-type doped layer, respectively.
  • the matrix material is preferably constituted of materials with a T g larger than about 75 °C, preferably of larger than about 100 °C, more preferably of larger than about 120 0 C. This value is an important factor for the dopants mobility; higher T g values lead to a stronger fixation of the dopant within the organic charge carrier transport layers.
  • the overall stability of the p-n-interface at the junction between the PIN-OLED units depends on both the T g of the matrix and the size of the dopants. A system consisting of a smaller dopant within a matrix with a high T g might be less stable than a larger size molecular dopant within a transport matrix having a lower T g .
  • the stability of the electronic device is increased if the thermal stability of the doped layers forming the p-n-junction is increased.
  • the thermal stability of a doped layer can be measured by heating the doped layer with a heating rate, for instance 1 K/min and monitoring the conductivity of the layer. As for any semiconductor, during the heating the conductivity increases. At a certain temperature (breakdown temperature), the conductivity decreases again because of morphological activities of the doped layer.
  • the matrix is preferably constituted of materials that have a breakdown temperature of greater than 75 °C, preferably of larger than 100 °C. The breakdown temperature increases with the T g of the matrix material and the atom count of the dopant molecule.
  • vapour pressure Another measure for the stability of the dopant molecule is its vapour pressure.
  • the vapour pressure at certain temperature is lowered with increasing the atom count of a compound. This is especially the case for conjugated molecules with high polarizability.
  • the van-der-Waals forces lead to a strong interaction of the molecules requiring more energy for vaporization.
  • the same van-der-Waals forces lead to strong interaction of the dopant molecule in the host material causing a fixation of the dopant in the doped layer. Consequently, a low vapour pressure of the dopant molecule can be beneficial for a stability of the doped layer and junctions formed with that doped layers.
  • evaporation temperature refers to the temperature, to which the dopant molecule has to be heated in a evaporator source in order to have the target deposition rate at the position of a substrate place over the source.
  • the deposition rate R can be written as M P e A
  • M is the molar mass of the evaporated compound
  • k is Boltzmann's constant
  • T is the source temperature
  • p is the density of the film
  • P is the vapour pressure
  • A is the source area
  • r is the distance of source and substrate plane.
  • dopants with a deposition rate of 0.005 nm/s at an evaporation temperature of about 120 °C or higher, preferably a temperature of about 140 °C or higher can be used to fabricate a stable p-n-junction.
  • a low vapour pressure, i.e. a high evaporation temperature is preferred to produce further stabilization of the p-n-junction in a manufacturing process. This is because a dopant molecule with a high volatility will lead to a contamination of the adjacent layers, especially the adjacent doped layer of the p-n-junction due to the high background pressure of the volatile dopant in the process chamber.
  • the transport matrix materials at the p-n-interface might also consist of the same material, if this material can be p- and n-doped by molecular dopants.
  • an organic light emitting device comprising an anode, a cathode, and a plurality of m (m > 1) organic electroluminescent units (3.1, ..., 3.m) each comprising an electroluminescent zone, where the organic electroluminescent units are provided upon each other in a stack or an inverted stack between the anode and the cathode, and where the p- n-junction is provided at an interface between adjacent organic electroluminescent units.
  • organic electroluminescent units (3.2, ..., 3.m-l) not adjacent to the anode (2) or the cathode comprise the p-type doped organic layer as a p-type doped hole transporting-layer, the n-type doped organic layer as a n-type doped electron-transporting layer, and the elec- troluminescent zone formed between the p-type doped hole transporting layer and the n- type doped electron transporting layer; - in the stack or the inverted stack the n-type doped electron-transporting layer of the k th (2 ⁇ k ⁇ m-2) organic electroluminescent unit (3.k) is directly followed by the p-type doped hole-transporting layer of the (k+l) ⁇ organic electroluminescent unit (3.k+l), thereby providing a direct contact between the n-type doped electron-transporting layer of the k ⁇ or- ganic electroluminescent unit (3.k) with the p-type doped
  • the first organic electroluminescent unit (3.1) comprises a n-type doped electron- transporting layer which is in contact with the p-type doped hole-transporting layer of the second organic electroluminescent unit (3.2)
  • the m" 1 organic electroluminescent unit (3.m) comprises a p-type doped hole- transporting layer which is in contact with the n-type doped electron-transporting layer of the (m-l) ⁇ organic electroluminescent unit (3.m-l).
  • a first electroluminescent unit (3.1) comprises the n-type doped organic layer as a n-type doped electron-transporting layer;
  • a second electroluminescent unit (3.2) comprises the p-type doped organic layer as a p-type doped hole transporting-layer;
  • the n-type doped electron- transporting layer of the first electroluminescent unit (3.1) is in contact with the p-type doped hole-transporting layer of the second organic electrolumi- nescent unit (3.2), thereby providing a p-n-junction between the two adjacent organic electroluminescent units (3.1, 3.2).
  • OLED units stacked organic electroluminescent units also referred to OLED units
  • OLED units can be directly laminated upon each other without the need of additional interlayers.
  • At least one of the m organic electroluminescent units further comprises at least one of the following layers: a hole-injection layer (HIL), an electron- injection layer (EIL), an interlayer in between the p-type doped hole-transporting layer and the electroluminescent zone, and a further interlayer between the n-type doped electron- transporting layer and the electroluminescent zone.
  • HIL hole-injection layer
  • EIL electron- injection layer
  • the p- and / or the n-doped transport layers of the p-n-junction might also individually consist of at least two layers in order to further stabilize the p-n-interface.
  • this is of advantage, if a stable transport matrix shows some absorption within the visible range of the electromagnetic spectrum.
  • the use of a two layer architecture allows for a stabilization of the interface in combination with a minimized absorption loss, as the stabilizing layer can be manufactured very thin.
  • the invention my be used for a stacked PIN-OLED where for the p- and / or the n-type doped layers of different units, different matrix and / or dopant materials are used. This is especially beneficial in the case of stacked multicolour devices, where different energetic levels of the transport layers are desired for an optimum performance of the individual OLED units.
  • Another advantage of such a multilayer architecture of the p-type or n-type doped transport layers of the units is, to reduce costs, if the more stable charge carrier transport matrix is more expensive than less stable alternative materials.
  • the material costs will necessarily be high due to the costs of the starting materials for the synthesis. This will even then be the case if the material is manufactured in mass production, which for standard organic materials usually leads to a significant cost reduction.
  • the use of a two layer architecture allows to reduce costs by minimizing the thickness of the layer formed by the expensive, stable material.
  • Another advantage of the multilayer structure is that the doping concentration of the p-doped and n-doped layers can be reduced in the vicinity of the junction to give a wider space-charge region and by this a better rectification of a p-n diode.
  • the doping concentration of other adjacent layers can be chosen in such a way that the conductivity is high enough to reduce ohmic losses.
  • Fig. 1 a schematic presentation of an electronic device comprising a p-n-junction
  • Fig. 2 for the electronic device in Fig. 1 a graphical depiction of the current vs. voltage
  • Fig. 3 a schematic presentation of a light emitting device with stacked organic elec- troluminescent units
  • Fig. 4 a schematic presentation of an organic electroluminescent unit used in the light emitting device in Fig. 3;
  • Fig. 5 a, 5b for a light emitting device according to an Example 1 a graphical depiction of the luminance vs. time (a) and the forward voltage vs. time (b), respectively;
  • Fig. 6a, 6b for a light emitting device according to an Example 2 a graphical depiction of the luminance vs. time (a) and the forward voltage vs. time (b), respectively
  • Fig. 7a, 7b for a light emitting device according to an Example 3 a graphical depiction of the luminance vs. time (a) and the forward voltage vs. time (b), respectively
  • Fig. 8a, 8b for a light emitting device according to an Example 4 (conventional) a graphical depiction of the luminance vs. time (a) and the forward voltage vs. time (b), respectively
  • Fig. 6a, 6b for a light emitting device according to an Example 2 a graphical depiction of the luminance vs. time (a) and the forward voltage vs. time (b), respectively
  • Fig. 7a, 7b for a light emitting device according to an Example 3 a graphical depiction of the luminance v
  • a structure of two organic layers 10, 11 provided in between an anode 12 made of indium tin oxide (ITO) and a cathode 13 made of aluminum is depicted schematically.
  • the two organic layers 10, 11 realize an organic p-n-junction.
  • Fig. 2 shows the current- voltage characteristic of this organic p-n-junction comprising a p-type doped hole transport layer and an n-type doped electron transport layer sandwiched between the ITO anode 12 and the aluminum cathode 13.
  • the organic layers 10, 11 and metal are deposited by thermal evaporation onto patterned and pre-cleaned ITO coated glass substrates in an ultrahigh vacuum system at a pressure of 10 "7 mbar without breaking vacuum.
  • the deposition rate and the thickness of the deposited layers are controlled by using a quarz crystal thickness monitor.
  • the area of the p-n-junction bet- ween the electrodes 12, 13 is 6,35 mm 2 .
  • the organic layer 10 is made of 45 nm 2,2',7,7'-Tetrakis-(N,N-di-methylphenylamino)-9,9'- spirobifluoren doped with 4 mole % 2-(6-Dicyanomethylene- 1,3, 4,5,7, 8-hexafluoro-6/-/-naph- talen-2-ylidene)- malononitrile thereby providing a p-type doped hole-transport layer.
  • the other organic layer 11 is made of 45 nm 2,4,7,9 - Tetraphenyl - 1,10 -phenanthroline doped with 4 mole % Tetrakis(l, 3,4,6,7, 8-hexahydro-2H-pyrimido[l,2-a]pyrimidinato)ditungsten (II) thereby providing an n-type doped electron-transport layer.
  • This is an organic p-n- junction.
  • Fig. 2 shows for the electronic device in Fig. 1 a graphical depiction of the current vs. voltage. Under backward operation at a voltage of -3 V a current of 0,3 mA is measured. In forward operation at a voltage of +3 V a current of 8 mA is flowing. Thus, a rectification ratio of nearly 30 at a very low voltage of ⁇ 3 V is observed. The rectification ratio is further increased at higher voltages.
  • a light emitting device comprises m (m > 1) electroluminescent units: 1. substrate, 2. base electrode, hole injecting anode,
  • each electroluminescent unit at least has a p-type doped hole-transporting layer closer to the anode, an n-type doped electron-transporting layer closer to the cathode and an electroluminescent layer in between (Fig. 3 and Fig. 4).
  • the p-type doped hole transport layer is closer to the anode and the n-type doped electron transport layer is closer to the cathode.
  • organic electroluminescent units (3.2, ..., 3.m-l) not adjacent to the anode (2) or the cathode comprise the p-type doped organic layer as a p-type doped hole transporting-layer, the n-type doped organic layer as a n-type doped electron-transporting layer, and the electroluminescent zone formed between the p-type doped hole transporting layer and the n- type doped electron transporting layer;
  • organic electroluminescent unit (3.k) is directly followed by the p-type doped hole-transporting layer of the (k+l) th organic electroluminescent unit (3.k+l), thereby providing a direct contact between the n-type doped electron-transporting layer of the k th organic electroluminescent unit (3.k) with the p-type doped hole-transporting layer of the (k+l) th organic electroluminescent unit (3.k+l); and - the first organic electroluminescent unit (3.1) comprises an n-type doped electron- transporting layer which is in contact with the p-type doped hole-transporting layer of the second organic electroluminescent unit (3.2), and the m ⁇ organic electroluminescent unit (3.m) comprises a p-type doped hole-transporting layer which is in contact with the n-type doped electron
  • the stability of the interface between the adjacent n-doped electron transport layer and p-doped hole transport layer, respectively, is optimized.
  • the interface of the base electrode and the electroluminescent unit adjacent to the base electrode and the interface between the m th electroluminescent unit adjacent to the top electrode and the top electrode may be formed in a different way to optimize the interface of the organic layers to the conductive electrodes.
  • a carbon fluoride interlayer (CF x ) on top of an ITO electrode improves the stability of the interface to the adjacent hole transport layer.
  • LiF or low work function materials may improve the injection from a top electrode to the adjacent electron transport layer.
  • beneficial interlayers may be used in conjunction of the present invention.
  • the materials used in the different light emitting devices are example materials which demonstrate layer setups in a conventional light emitting device and preferred embodiments of the invention.
  • the organic layers and metal are deposited by thermal evapora- tion onto patterned and pre-cleaned indium tin oxide (ITO) coated glass substrates in an ultrahigh vacuum system at 10 '7 mbar (base pressure) without breaking vacuum.
  • the deposition rate and the thickness of the deposited layer are controlled by using a quartz crystal thickness monitor.
  • the devices described in the following comprise an anode, a cathode, and a plurality of a number of m (m > 1) organic electroluminescent units, directly stacked upon each other, forming a cascaded organic electroluminescent device.
  • the organic electroluminescent unit (OLED unit) not adjacent to the electrodes comprises at least a p-type doped hole- transporting layer, an electroluminescent layer and an n-type doped electron-transporting layer.
  • the n-type doped electron-transporting layer comprises an organic main material doped with a molecular donor-type substance and the p-type doped hole-transporting layer comprises an organic main material doped with a molecular acceptor-type substance.
  • the organic electroluminescent units might furthermore comprise additional hole-injection layers and/or electron injection layers and / or hole-blocking layers and / or electron-blocking layers and / or other types of interlayers between the EML and the HTL and / or the ETL.
  • the electroluminescent layers might consist of one or more consecutive layers containing one or more organic host materials and one or more fluorescent or phosphorescent electroluminescent emitter materials.
  • the electroluminescent layer may be formed from small organic molecules or from organic polymers.
  • the m OLED units are consecutively stacked upon each other in a way that the n-type doped electron-transporting layer of the k th unit (0 ⁇ k ⁇ m) is directly followed by the p-type doped hole-transporting layer of the (k+1)* unit without any additional intermediate layers.
  • Example 1 a structure for a conventional light emitting device is provided as follows:
  • the device reaches a brightness of 1000 cd/m 2 at 9,7 V with a current efficiency of 8,8 cd/A.
  • Fig. 5a and 5b show the lifetime behavior of the conventional light emitting device according to Example 1.
  • Four contacts being on the same substrate are driven at different current densities in DC operation.
  • the driving voltage vs. time characteristics shows a very steep increase of the forward voltage needed for the driven current during the operation of the devices.
  • the measurement setup reaches its voltage limit, which can be observed as a luminance breakdown in the luminance vs. time plot.
  • the conventional light emitting device according to Example 1 comprises a conventional p-n- junction architecture using Cs as an elemental metallic n-dopant. It can be clearly seen, that the performance of the device undergoes rapid breakdown during operation. Even at a rela- tively low current density of 5 mA/cm 2 the device operates less than 50 hours.
  • Example 2 a structure for a light emitting device is provided as follows: 2.1 50 nm 2,2',7,7'-Tetrakis-(N,N-di-methylphenylamino)-9,9'-spirobifluorene doped with 4 mole % 2-(6-Dicyanomethylene-l ,3,4,5,7,8-hexafluoro-6H-naphtalen-2-ylidene)- malononitrile as p-type doped hole-transport layer;
  • the device reaches a brightness of 1000 cd/m 2 at 8,7 V with a current efficiency of 11 ,5 cd/A.
  • Fig. 6a and 6b show the lifetime behavior of the device.
  • Four OLED contacts being on the same substrate are driven at different current densities in DC operation.
  • the voltage increase for the molecularly doped device is significantly flatter as for a device using Cs doping (example 1).
  • the voltage limit of the lifetime measurement setup is reached after 550 hours, which is more than ten times as long as for the Cs doped sample.
  • Example 3 a structure for a light emitting device is provided as follows: 3.1 75 nm 2,2',7,7'-Tetrakis-(N,N-di-methylphenylamino)-9,9'-spirobifluorene doped with 4 mole % 2-(6-Dicyanomethylene-l ,3,4,5,7, 8-hexafluoro-6H-naphtalen-2-ylidene)- malononitrile (p-type doped hole-transport layer); 3.2 10 nm NPB (interlayer);
  • Tetrakis(l,3,4,6,7,8-hexahydro-2H-pyrimido[l,2-a]pyrimidinato)ditungsten (II) (n-type doped electron-transport layer); 3.11 100 nm Aluminum (reflective cathode).
  • the device reaches a brightness of 1000 cd/m 2 at 6,6 V with a current efficiency of 61,2 cd/A.
  • Fig. 7a and 7b show the lifetime behavior of the device.
  • Four OLED contacts being on the same substrate are driven at different current densities in DC operation.
  • the voltage limit of the measurement setup, 22 V in this example is reached after approximately 120 hours for the highest current density, 30 mA/cm 2 . For lower current densities the voltage limit is not reached within the first 300 hours of measurement.
  • Example 4 (conventional)
  • Example 4 a structure for a conventional light emitting device is provided as follows: 4.1 50 nm 2,2',7,7'-Tetrakis-(N,N-di-methylphenylamino)-9,9'-spirobifluorene doped with 4 mole % 2-(6-Dicyanomethylene-l, 3,4,5, 7,8-hexafluoro-6H-naphtalen-2-ylidene)- malononitrile (p-type doped hole-transport layer);
  • Tetrakis(l, 3,4,6,7, 8-hexahydro-2H-pyrimido[l,2-a]pyrimidinato)ditungsten (II) (n-type doped electron-transport layer); 4. 100 nm Aluminum (reflective cathode).
  • the device reaches a brightness of 1000 cd/m 2 at 2,97 V with a current efficiency of 16,4 cd/A.
  • Fig. 8a and 8b show the lifetime behavior of the device.
  • Four OLED contacts being on the same substrate are driven at different current densities in DC operation.
  • Fig. 8a shows the operation lifetime of the device, which is estimated to be 11000 hours at 1000 cd/m 2 initial brightness.
  • the forward voltage needed for driving the currents applied during the lifetime measurements are shown in Fig. 8b.
  • the increase in driving voltage is less than 10 % up to 50 % luminance decay of the device, which is a very small value.
  • Example 5 a structure for a light emitting device is provided as follows: 5.1 50 nm 2,2',7,7'-Tetrakis-(N,N-di-methylphenylamino)-9,9'-spirobifluorene doped with 4 mole % 2-(6-Dicyanomethylene-l ,3,4,5,7, 8-hexafiuoro-6H-naphtalen-2-ylidene)- malononitrile (p-type doped hole-transport layer); 5.2 10 nm NPB (interlayer);
  • Tetrakis(l ,3,4,6,7,8-hexahydro-2H-pyrimido[l ,2-a]pyrimidinato)ditungsten (II) (n-type doped electron-transport layer); 5.11 100 nm Aluminum (reflective cathode).
  • the device reaches a brightness of 1000 cd/m 2 at 5,70 V with a current efficiency of 37,1 cd/A. This is more than twice the current efficiency of the device disclosed in comparative Example 4, however the operating voltage needed to reach a bright- ness of 1000 cd/m 2 is less than doubled. Therefore the operation parameters of this stacked OLED are even better than of the non stacked reference device.
  • Fig. 9a and 9b show the lifetime behavior of the device.
  • Four OLED contacts being on the same substrate are driven at different current densities in DC operation.
  • Fig. 9a shows the operation lifetime of the device, which is estimated to be 17000 hours at 1000 cd/m 2 initial brightness.
  • the forward voltage needed for driving the currents applied during the lifetime measurements are shown in Fig. 9b.
  • the increase in driving voltage is less than 10 % up to 50 % luminance decay of the device, which is a very small value for OLEDs.
  • Example 5 demonstrates, that stacking allows for prolonged lifetimes as compared to non stacked reference devices.
  • Indium (III) Tris(l-phenylisoquinoline), which has a T g of > 120 0 C as charge carrier transport matrix material for the molecular dopants leads to significant improvements in stability of the p-n-interface and an improved stability of the doped films.
  • the increase in operating voltage can by this measure be reduced to a level equal to non stacked OLEDs, therefore the lifetime of the device is no longer limited by the p-n-interface degradation.
  • the direct stacking of PIN-OLEDs onto each other without the use of interlayers therefore can be carried out without a loss in device performance regarding efficiency or lifetime.
  • Example 6 a structure for a light emitting device is provided as follows: 6.1 50 ran 2,2',7,7'-Tetrakis-(N,N-di-methylphenylamino)-9,9'-spirobifluorene doped with 4 mole % 2-(6-Dicyanomethylene-l ,3,4,5,7,8-hexafluoro-6H-naphtalen-2-ylidene)- malononitrile (p-type doped hole-transport layer); 6.2 lO nm NPB (interlayer);
  • Dicyanomethylene-l,3,4,5,7,8-hexafiuoro-6H-naphtalen-2-ylidene)-malononitrile (p- type doped hole-transport layer); 6.8 30 nm 2,2',7,7'-Tetrakis-(N,N-di-methylphenylamino)-9,9'-spirobifluorene doped with 4 mole % 2-(6-Dicyanomethylene-l ,3,4,5, 7,8-hexafluoro-6H-naphtalen-2-ylidene)- malononitrile (p-type doped hole-transport layer);
  • the n-type doped charge carrier transport layer of the first OLED unit consists of two layers as well as the p-type doped charge carrier transport layer of the second OLED unit consists of two layers.
  • the thickness of the p- and n-doped Iridium (III) Tris(l-phenylisoquinoline) layers at the interface of the two PIN-OLED units is 60 nm in total.
  • the device reaches a brightness of 1000 cd/m 2 at 5,49 V with a current efficiency of 54,4 cd/A.
  • Fig. 10a shows the operation lifetime of the device, which is estimated to be approx. 50000 hours at 1000 cd/m 2 initial brightness.
  • the forward voltage needed for driving the currents applied during the lifetime measurements are shown in Fig. 10b.
  • the increase in driving volt- age is less than 10 % up to 50 % luminance decay of the device, which is a very small value for OLEDs.
  • Example 7 a structure for a light emitting device is provided as follows:
  • the n-type doped charge carrier transport layer of the first OLED unit consists of two layers as well as the p-type doped charge carrier transport layer of the second OLED unit consists of two layers.
  • the thickness of the p- and n-doped Indium (III) Tris(l-phenylisoquinolinc) layers at the interface of the two PIN-OLED units is 10 nm in total.
  • the device reaches a brightness of 1000 cd/m 2 at 5,66 V with a current efficiency of 54,5 cd/A.
  • Fig. 11a shows the operation lifetime of the device, which is estimated to be approx. 50000 hours at 1000 cd/m 2 initial brightness.
  • the forward voltage needed for driving the currents applied during the lifetime measurements are shown in Fig. 1 Ib.
  • the increase in driving voltage is less than 10 % up to 50 % luminance decay of the device, which is a very small value for OLEDs.
  • the reduction of the thickness of the doped Iridium (III) Tris(l-phenylisoquinoline) layers is beneficial to minimize absorption losses of the light emitted within the light emitting device, furthermore the reduced thickness of the doped Iridium (III) Tris(l-phenylisoquinoline) layers might lead to cost reductions in a mass production of the devices.

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  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
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  • Electroluminescent Light Sources (AREA)

Abstract

La présente invention concerne un dispositif électronique comprenant une structure en couches faite de couches organiques. Cette structure en couches comprend une jonction p-n entre, d'une part une couche organique dopée n faite d'un matériau matrice organique dopé d'un dopant de type n, et d'autre part une couche organique dopée p faite d'un matériau matrice organique dopé d'un dopant de type p. En outre, le dopant de type n et le dopant de type p sont tous les deux des dopants moléculaire. Le potentiel réducteur du dopant de type p est d'au moins environ 0 V rapporté à Fc / Fc+. De plus, le potentiel d'oxydation du dopant de type n est d'au moins environ -1.5 V rapporté Fc / Fc+.
PCT/EP2006/012516 2005-12-23 2006-12-22 Dispositif electronique a structure en couche faite de couches organiques WO2007071450A1 (fr)

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US12/158,479 US7830089B2 (en) 2005-12-23 2006-12-22 Electronic device with a layer structure of organic layers
JP2008546288A JP5583345B2 (ja) 2005-12-23 2006-12-22 有機層の層構造を備える電子デバイス
KR1020087018120A KR101460117B1 (ko) 2005-12-23 2006-12-22 유기층들의 층 구조물을 갖는 전자 소자
CN2006800528745A CN101375429B (zh) 2005-12-23 2006-12-22 具有有机层的层结构的电子器件

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EP05028308.4 2005-12-23
EP06001231.7 2006-01-20
EP06001231A EP1804309B1 (fr) 2005-12-23 2006-01-20 Dispositif électronique avec une structure en couches de nature organique

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010540701A (ja) * 2007-09-28 2010-12-24 オスラム オプト セミコンダクターズ ゲゼルシャフト ミット ベシュレンクテル ハフツング 放射を発する有機素子
JP2011501422A (ja) * 2007-10-15 2011-01-06 ノヴァレッド・アクチエンゲゼルシャフト 有機エレクトロルミネセンス素子
WO2011045253A1 (fr) 2009-10-13 2011-04-21 Basf Se Mélanges pour produire des couches photoactives pour des cellules solaires organiques et des photodétecteurs organiques
DE102010004453A1 (de) * 2010-01-12 2011-07-14 Novaled AG, 01307 Organisches lichtemittierendes Bauelement
US8603642B2 (en) 2009-05-13 2013-12-10 Global Oled Technology Llc Internal connector for organic electronic devices
FR2992097A1 (fr) * 2012-06-18 2013-12-20 Astron Fiamm Safety Diode electroluminescente organique de type pin
EP2706584A1 (fr) 2012-09-07 2014-03-12 Novaled AG Matériau semi-conducteur de transport de charge et dispositif semi-conducteur
US8734962B2 (en) 2007-05-21 2014-05-27 Osram Opto Semiconductors Gmbh Phosphorescent metal complex compound radiation emitting component comprising a phosphorescent metal complex compound and method for production of a phosphorescent metal complex compound
EP3184534A1 (fr) 2015-12-21 2017-06-28 UDC Ireland Limited Complexes de métaux de transition comportant des ligands tripodes et leur utilisation dans des delo
EP3208863A1 (fr) 2016-02-22 2017-08-23 Novaled GmbH Matériau semi-conducteur de transport de charge et dispositif électronique le comprenant
EP3208862A1 (fr) 2016-02-22 2017-08-23 Novaled GmbH Matériau semi-conducteur de transport de charge et dispositif électronique comprenant celui-ci
EP3466957A1 (fr) 2014-08-08 2019-04-10 UDC Ireland Limited Oled comprenant un complexe de carbène-métal à imidazo-quinoxaline électroluminescent

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1339112A2 (fr) * 2002-02-15 2003-08-27 Eastman Kodak Company Dispositif électroluminescent organique comportant des éléments électroluminescents empilés
EP1478025A2 (fr) * 2003-05-13 2004-11-17 EASTMAN KODAK COMPANY (a New Jersey corporation) Dispositifs organiques électroluminescents en cascade ayant des unités de connexion à couches organiques de type n et de type p
US6908783B1 (en) * 2003-12-04 2005-06-21 Novaled Gmbh Method of doping organic semiconductors with quinonediimine derivatives

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1339112A2 (fr) * 2002-02-15 2003-08-27 Eastman Kodak Company Dispositif électroluminescent organique comportant des éléments électroluminescents empilés
EP1478025A2 (fr) * 2003-05-13 2004-11-17 EASTMAN KODAK COMPANY (a New Jersey corporation) Dispositifs organiques électroluminescents en cascade ayant des unités de connexion à couches organiques de type n et de type p
US6908783B1 (en) * 2003-12-04 2005-06-21 Novaled Gmbh Method of doping organic semiconductors with quinonediimine derivatives

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8734962B2 (en) 2007-05-21 2014-05-27 Osram Opto Semiconductors Gmbh Phosphorescent metal complex compound radiation emitting component comprising a phosphorescent metal complex compound and method for production of a phosphorescent metal complex compound
US9966544B2 (en) 2007-05-21 2018-05-08 Osram Oled Gmbh Phosphorescent metal complex compound radiation emitting component comprising a phosphorescent metal complex compound and method for production of a phosphorescent metal complex compound
US9139764B2 (en) 2007-09-28 2015-09-22 Osram Opto Semiconductors Gmbh Organic radiation-emitting component
JP2010540701A (ja) * 2007-09-28 2010-12-24 オスラム オプト セミコンダクターズ ゲゼルシャフト ミット ベシュレンクテル ハフツング 放射を発する有機素子
JP2011501422A (ja) * 2007-10-15 2011-01-06 ノヴァレッド・アクチエンゲゼルシャフト 有機エレクトロルミネセンス素子
US8466453B2 (en) 2007-10-15 2013-06-18 Novaled Ag Organic electroluminescent component
US8603642B2 (en) 2009-05-13 2013-12-10 Global Oled Technology Llc Internal connector for organic electronic devices
WO2011045253A1 (fr) 2009-10-13 2011-04-21 Basf Se Mélanges pour produire des couches photoactives pour des cellules solaires organiques et des photodétecteurs organiques
US9368729B2 (en) 2009-10-13 2016-06-14 Basf Se Mixtures for producing photoactive layers for organic solar cells and organic photodetectors
DE102010004453A1 (de) * 2010-01-12 2011-07-14 Novaled AG, 01307 Organisches lichtemittierendes Bauelement
FR2992097A1 (fr) * 2012-06-18 2013-12-20 Astron Fiamm Safety Diode electroluminescente organique de type pin
US9419238B2 (en) 2012-06-18 2016-08-16 Astron Fiamm Safety PIN-type organic light emitting diode
WO2013189850A1 (fr) * 2012-06-18 2013-12-27 Astron Fiamm Safety Diode électroluminescente organique de type pin
EP2706584A1 (fr) 2012-09-07 2014-03-12 Novaled AG Matériau semi-conducteur de transport de charge et dispositif semi-conducteur
US11322687B2 (en) 2012-09-07 2022-05-03 Novaled Gmbh Charge transporting semi-conducting material and semi-conducting device
EP3466957A1 (fr) 2014-08-08 2019-04-10 UDC Ireland Limited Oled comprenant un complexe de carbène-métal à imidazo-quinoxaline électroluminescent
EP3184534A1 (fr) 2015-12-21 2017-06-28 UDC Ireland Limited Complexes de métaux de transition comportant des ligands tripodes et leur utilisation dans des delo
US10490754B2 (en) 2015-12-21 2019-11-26 Udc Ireland Limited Transition metal complexes with tripodal ligands and the use thereof in OLEDs
WO2017144516A1 (fr) 2016-02-22 2017-08-31 Novaled Gmbh Matériau semi-conducteur à transfert de charge et dispositif électronique le comprenant
EP3208862A1 (fr) 2016-02-22 2017-08-23 Novaled GmbH Matériau semi-conducteur de transport de charge et dispositif électronique comprenant celui-ci
EP3208863A1 (fr) 2016-02-22 2017-08-23 Novaled GmbH Matériau semi-conducteur de transport de charge et dispositif électronique le comprenant

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