Patent DE-102007033209-A1 (DE)
Title: Organic light-emitting diode comprises electrode formed as cathode, counter electrode formed as anode, and organic region, which is arranged between the electrode and the counter electrode and has region emitting organic light
Inventor: REINEKE SEBASTIAN
IPC: H01L51/56
Filed: 2007-07-11
Abstract: The organic light-emitting diode, comprises an electrode formed as cathode (2), a counter electrode formed as anode (1) and an organic region, which is arranged between the electrode and the counter electrode and has an organic light emitting region (4). The organic light-emitting region has a first emission layer and is formed in the visible spectral region in the application of an electric voltage at the electrode and the counter electrode. The emission layer has a fluorescent emitter emitting light in the blue or blue green spectral region and a phosphorescent emitter. The organic light-emitting diode, comprises an electrode formed as cathode (2), a counter electrode formed as anode (1) and an organic region, which is arranged between the electrode and the counter electrode and has organic light emitting region (4). The organic light-emitting region has a first emission layer and is formed in the visible spectral region in the application of an electric voltage at the electrode and the counter electrode. The emission layer has a fluorescent emitter emitting light in the blue or blue green spectral region and a phosphorescent emitter emitting light in non-blue spectral regions. In the emission layer for the fluorescent emitter, triplet energy for an energy level of a triplet condition is 0.1 eV than that of the phosphorescent emitter. The light emitting organic region of 25% portion of the produced light in the visible spectral region is formed as fluorescence light of singlet state of the fluorescent emitter. The emission layer consists of an organic material, in which the fluorescent emitters with a concentration of 0.1-50 mol% and the phosphorescent emitter are placed. The organic light emitting region comprises a second emission layer with phosphorescent emitters emitting light in the non-blue spectral region. The both emission layers are formed in inclined manner. The emission layers are formed as holes transporting layer or as electron transporting layer (5). A distance between a surface of the first emission layer turned to the electrode formed as cathode and a surface of the cathode turned to the first emission layer is smaller than a distance between a surface of the second emission layer turned to the cathode and a surface of the cathode turned to the second emission layer. A distance between a surface of the first emission layer turned to the counter electrode formed as anode and a surface of the anode turned to the first emission layer is smaller than a distance between a surface of the second emission layer turned to the anode and a surface of the anode turned to the second emission layer. A hole block layer is arranged between the first emission layer and the cathode, and is the electron transporting layer. The organic material of the hole or electron block layer (7) has a highest occupied molecular orbital (HOMO) level, which is 0.3 eV as the HOMO level of the fluorescent emitter in the first emission layer. The electron block layer is arranged between the first emission layer and the anode and is holes transporting layer. The first emission layer and/or the second emission layer are formed in multi-layered manner. The emission layer has a thickness of 10-100 Nm. The organic light emitting region is a white light emitting region. The phosphorescent emitters in the first or second emission layers emit light in red, orange, yellow or green spectral region. A p- or n-doped organic layer is formed between the organic light emitting region and the electrode and/or between the organic light emitting region and the counter electrode. The p-doped organic layer is formed with an acceptor material and the n-doped organic layer is formed with a donor material. The fluorescent emitter is a metal-organic compound or a complex compound with a metal with an atomic number less than 40. The electrode is formed as an optically reflecting electrode. A charge carrier transport layer is arranged between the emission zone and the optically reflecting electrode and has a layer thickness dl, which is dl=(lambda /4)-ET, where ET is the penetration depth of electromagnetic waves in the optically reflecting electrode and lambda is a wavelength of 380-500nm. A space region with a first concentration of the phosphorescent emitter and an additional space region with a second concentration different from the first concentration are formed in the emission layer. The space region is free from an admixture of the phosphorescent emitter. An arrangement is arranged between the anode and the cathode. The emission layer has a sub-structuring with zones, which comprise zones consisting of host material and zones consisting of a mixture system with phosphorescent emitting coloring material. The zones are formed as a laminated structure or as spherical or cubic bodies. The boundary surfaces of the zones consisting of the mixing system are removed in a distance within the nanometer range from each other, where the distance corresponds to a thickness of the zones consisting of the host materials, which have triplet energy (T host) greater than the triplet energy (T emitter) of the phosphorescent emitting coloring material. The zones consisting of host material is formed in sequence with zones of a material combination of several materials, which have triplet energies (T comb) greater than the triplet energies (T emitter) of the phosphorescent emitting coloring material. The mixture systems are formed with different phosphorescent emitting coloring materials. A distance between the zones consisting of host material between is 2-20 nm. The zones have a spatial expansion of 0.5-100 nm. The organic layers consist of vacuum vapor-deposited small molecules or of polymers. The emission layer has a further sub-structuring, with which a mixed color light combination of different emitting coloring materials is intended in different zones of a mixed region. The triplet energies (T host) of host materials are smaller than or equal to the triplet energies of the emitter coloring materials. An independent claim is included for a procedure for manufacturing a phosphorescent organic light emitting diode.