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  • 1
    Electronic Resource
    Electronic Resource
    Nearly 100% internal phosphorescence efficiency in an organic light-emitting device (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 5048-5051 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We demonstrate very high efficiency electrophosphorescence in organic light-emitting devices employing a phosphorescent molecule doped into a wide energy gap host. Using bis(2-phenylpyridine)iridium(III) acetylacetonate [(ppy)2Ir(acac)] doped into 3-phenyl-4(1′-naphthyl)-5-phenyl-1,2,4-triazole, a maximum external quantum efficiency of (19.0±1.0)% and luminous power efficiency of (60±5) lm/W are achieved. The calculated internal quantum efficiency of (87±7)% is supported by the observed absence of thermally activated nonradiative loss in the photoluminescent efficiency of (ppy)2Ir(acac). Thus, very high external quantum efficiencies are due to the nearly 100% internal phosphorescence efficiency of (ppy)2Ir(acac) coupled with balanced hole and electron injection, and triplet exciton confinement within the light-emitting layer. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1409582
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  • 2
    Electronic Resource
    Electronic Resource
    Management of singlet and triplet excitons for efficient white organic light-emitting devices (2006)
    [s.l.] : Nature Publishing Group
    Nature 440 (2006), S. 908-912 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Lighting accounts for approximately 22 per cent of the electricity consumed in buildings in the United States, with 40 per cent of that amount consumed by inefficient (∼15 lm W-1) incandescent lamps. This has generated increased interest in the use of white ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature04645
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  • 3
    Electronic Resource
    Electronic Resource
    The path to ubiquitous and low-cost organic electronic appliances on plastic (2004)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 428 (2004), S. 911-918 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Organic electronics are beginning to make significant inroads into the commercial world, and if the field continues to progress at its current, rapid pace, electronics based on organic thin-film materials will soon become a mainstay of our technological existence. Already products based on active ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature02498
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  • 4
    Electronic Resource
    Electronic Resource
    Efficient bulk heterojunction photovoltaic cells using small-molecular-weight organic thin films (2003)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 425 (2003), S. 158-162 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The power conversion efficiency of small-molecular-weight and polymer organic photovoltaic cells has increased steadily over the past decade. This progress is chiefly attributable to the introduction of the donor–acceptor heterojunction that functions as a dissociation site for the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature01949
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  • 5
    Electronic Resource
    Electronic Resource
    A polymer/semiconductor write-once read-many-times memory (2003)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 426 (2003), S. 166-169 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Organic devices promise to revolutionize the extent of, and access to, electronics by providing extremely inexpensive, lightweight and capable ubiquitous components that are printed onto plastic, glass or metal foils. One key component of an electronic circuit that has thus far received ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature02070
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  • 6
    Electronic Resource
    Electronic Resource
    Strain compensated In1−xGaxAs(x〈0.47) quantum well photodiodes for extended wavelength operation (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 2263-2265 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The use of highly strained (−2.0%) In0.83Ga0.17As quantum wells for the detection of light to a wavelength of λ∼2.0 μm is reported. Crystal quality for a 50 period multiple quantum well (MQW) detector grown on InP substrates is maintained through strain compensation using tensile strained In0.83Ga0.17P barriers. Transmission electron microscopy and double crystal x-ray diffraction reveal smooth interfaces and no observable defects for In0.83Ga0.17As layers with widths less than 80 Å. Single-pass quantum efficiencies of 30% have been achieved at λ=1.95 μm, using a 75 μm diam MQW, strain-compensated, top illuminated, low dark current (∼250 pA at 20 V) p-i-n detector. The theoretical cutoff wavelength limit for diodes fabricated using this technique is calculated to be λ=2.15 μm. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.121696
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  • 7
    Electronic Resource
    Electronic Resource
    Growth of abrupt InGaAs(P)/In(GaAs)P heterointerfaces by gas source molecular beam epitaxy (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 201-209 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We demonstrate a novel method for the growth of abrupt InGaAs(P)/In(GaAs)P heterojunctions by gas source molecular beam epitaxy. We find that exposure of freshly grown InP to an As flux during growth interruption between layers of different compositions results in the substitution of surface P atoms and As atoms, thereby generating a strained transition layer at each interface. By assuring a group-III stabilized surface during interruption required to grow InGaAs(P)/In(GaAs)P heterointerfaces, As/P substitution can be avoided, thereby resulting in improved interface quality. Heterointerface abruptness was examined by double-crystal x-ray diffraction and low temperature photoluminescence. The results show that the interfaces grown with the modified switching sequence are considerably more abrupt than those obtained using conventional sequences where As/P interdiffusion extends over several monolayers. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359370
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  • 8
    Electronic Resource
    Electronic Resource
    Electroluminescence mechanisms in organic light emitting devices employing a europium chelate doped in a wide energy gap bipolar conducting host (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 8049-8055 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The mechanism for energy transfer leading to electroluminescence (EL) of a lanthanide complex, Eu(TTA)3phen (TTA=thenoyltrifluoroacetone,phen=1,10-phenanthroline), doped into 4,4′-N,N′-dicarbazole-biphenyl (CBP) host is investigated. With the device structure of anode/hole transport layer/Eu(TTA)3phen(1%):CPB/electron transport layer/cathode, we achieve a maximum external EL quantum efficiency (η) of 1.4% at a current density of 0.4 mA/cm2. Saturated red Eu3+ emission based on 5Dx–7Fx transitions is centered at a wavelength of 612 nm with a full width at half maximum of 3 nm. From analysis of the electroluminescent and photoluminescent spectra, and the current density–voltage characteristics, we conclude that direct trapping of holes and electrons and subsequent formation of the excitons occurs on the dopant, leading to high quantum efficiencies at low current densities. With increasing current between 1 and 100 mA/cm2, however, a significant decrease of η along with an increase in CBP host emission is observed. We demonstrate that the decrease in η at high current densities can be explained by triplet–triplet annihilation. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373496
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  • 9
    Electronic Resource
    Electronic Resource
    Effects of film morphology and gate dielectric surface preparation on the electrical characteristics of organic-vapor-phase-deposited pentacene thin-film transistors (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 81 (2002), S. 268-270 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Organic vapor phase deposition was used to grow polycrystalline pentacene channel thin-film transistors. Substrate temperature, chamber pressure during film deposition, and growth rate were used to vary the crystalline grain size of pentacene films on O2-plasma treated SiO2 from 0.2 to 5 μm, leading to room-temperature saturation regime field-effect hole mobilities (μeff) from 0.05±0.02 to 0.5±0.1 cm2/V s, respectively. Surface treatment of SiO2 with octadecyltrichlorosilane (OTS) prior to pentacene deposition resulted in μeff≤1.6 cm2/V s, and drain current on/off ratios of ≤108 at room temperature, while dramatically reducing the average grain size. X-ray diffraction studies indicate that the OTS treatment decreases the order of the molecular stacks. This suggests an increased density of flat-lying molecules, accompanying the improvement of the hole mobility at the pentacene/OTS interface. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1491009
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  • 10
    Electronic Resource
    Electronic Resource
    Growth and characterization of small band gap (∼0.6 eV) InGaAsN layers on InP (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 1287-1289 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We demonstrate the growth of small band gap (Eg∼0.6 eV) strained and lattice matched single crystal InGaAsN alloys on InP substrates. InGaAsN layers with N concentrations varying from 0.6% to 3.25% were grown by gas source molecular beam epitaxy using a radio frequency plasma nitrogen source. Lattice-matched, 0.5-μm-thick InGaAsN layers with smooth surface morphologies and abrupt interfaces were achieved. Low temperature photoluminescence measurements reveal a band gap emission wavelength of 1.9 μm (at 20 K) for lattice matched InGaAsN (N∼2%). Tensile strained In0.53Ga0.47As/In0.53Ga0.47As0.994N0.006 multiple quantum wells emitting at 1.75 μm at 20 K are also reported. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.123526
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