Browsing by Author "Gaponik, Nikolai"

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    Cathodic and Anodic Material Diffusion in Polymer/Semiconductor-Nanocrystal Composite Devices
    (John Wiley & Sons, Ltd, 2007-01-01T00:00:00Z) Gallardo, Diego E.; Bertoni, Cristina; Dunn, Steve; Gaponik, Nikolai; Eychmüller, Alexander
    In the present day, the information technologies and telecommunications sector continually increase their demand for low cost, low power consumption, high performance electroluminescent devices for display applications. Furthermore, general lighting applications, such as white light and large array colour displays, would also benefit from an increase in the overall efficiency. Several technologies are being investigated to fulfill these needs, such as organic light emitting diodes (OLED), polymeric light emitting diodes (PLED) and field effect emission devices. A new and promising technology is light emitting devices (LEDs) based on nanostructured materials. With organic LEDs (OLEDs) already making an impact on the market in an increasingly large number of applications, hybrid technologies based on organic/inorganic nano-composites are a potential the next step. The incorporation of highefficiency fluorescent semiconductor nanoparticles has been shown to have a beneficial effect on device performance, [1] modify the colour output from the device 2 and provide a simplified route to generation of LED type devices. [3]
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    Fabrication and characterization of red-emitting electroluminescent devices based on thiol-stabilized semiconductor nanocrystals
    (American Institute of Physics (AIP), 2007-01-15) Bertoni, Cristina; Gallardo, Diego E.; Dunn, Steve; Gaponik, Nikolai; Eychmüller, Alexander
    Thiol-capped CdTe nanocrystals were used to fabricate light-emitting diodes, consisting of an emissive nanocrystal multilayer deposited via layer-by-layer, sandwiched between indium-tin-oxide and aluminum electrodes. The emissive and electrical properties of devices with different numbers of nanocrystal layers were studied. The improved structural homogeneity of the nanocrystal multilayer allowed for stable and repeatable current- and electroluminescence-voltage characteristics. These indicate that both current and electroluminescence are electric-field dependent. Devices were operated under ambient conditions and a clear red-light was detected. The best-performing device shows a peak external efficiency of 0.51% and was measured at 0.35mA/cm2 and 3.3V.