This thesis describes the charge transport and spectral properties of light-emitting field-effect transistors with regard to their components and in combination with plasmonic nanoantennas and planar microcavities. Ambipolar field-effect transistors emit light by recombination and radiative relaxation of charge carriers in a semiconducting material. The injection and transport of both types of charge carriers, electrons and holes, is a prerequisite for light emission. Donor-acceptor copolymers and semiconducting single-walled carbon nanotubes fulfill this criterion, provide high charge carrier mobilities and exhibit near-infrared emission due to a narrow bandgap. Comparing several polymers with similar backbones reveals a decreasing emission efficiency with a decreasing bandgap, as well as electroluminescence quenching in the recombination zone due to the presence of charge carriers. High brightness as a result of high currents is not only attributed to a high mobility of the semiconductor, but also to the high carrier densities supported by the gate dielectric and charge injection by the electrode material. A hybrid dielectric of a metal oxide with high permittivity and a thin polymer interlayer with low trap density enables high currents at low operating voltages. Electrodes made of a thick carbon nanotube film exploit the one-dimensional properties of carbon nanotubes in order to decrease the resistance for charge injection for a wide bandgap polymer semiconductor. Semiconducting carbon nanotubes do not benefit from this effect due to their high mobility. Thus, each component of the transistor is investigated in order to tune the charge transport properties, the emission spectrum and the light output intensity. Combining plasmonic nanostructures or microcavities with a light-emitting transistor enables the manipulation of the spectral properties of the device without replacing the emitting material. The coupling of the emitter's excitons to the localized plasmon resonances of randomly arranged colloidal ...
Electroluminescence in Light-Emitting Transistors with Plasmonic and Optical Cavities - Charge Transport, Emission Enhancement and Strong Coupling ; Elektrolumineszenz in Lichtemittierenden Transistoren mit Plasmonischen und Optischen Kavitäten - Ladungstransport, Emissionsverstärkung und Starke Kopplung
2019-01-01
Theses
Electronic Resource
English
FAHRZEUGINNENBELEUCHTUNGSSYSTEME MIT ORGANISCHEN LICHTEMITTIERENDEN DIODEN
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