Light emitting ambipolar organic transistors

The goal of the research proposal is the development of organic light emitting optoelectronic transistors. A key target will be the introduction of ambipolar materials in the device structure. Not only intrinsic charge transport properties of organic semiconductors but also the influence of functional insulators as gate dielectrics on the electroluminescence efficiency will be studied. The first phase of the project is devoted to screening of existing as well as development of new functional gate dielectrics suitable for fabrication of light emitting field effect transistors (LFETs). In the second phase, selected systems with ambipolar charge transport properties will be optimized in respect to control and preferentially to balance the mobilities of the charge carriers of both signs, holes and electrons. As the project makes progress, we will concentrate on the studies of charge carrier recombination within the transistor channel that can result in light emission. Several contributions to the electroluminescent efficiency, such as the role of gate dielectrics, the role of injecting electrodes and the proper choice of organic semiconductors with respect to its electronic energy levels will be investigated. For a deeper understanding of the device physics, we will combine the experimental results with theoretical models. Such a light emitting devices with a proper control of ambipolar charge injection may be a step towards the development of organic lasers. In addition to light emission, ambipolar OFETs also offer good opportunity to compare electron versus hole mobilities in a given material under the same experimental conditions and to assess their dependence on electric field, temperature, and charge carrier density. These investigations are important for a deeper basic understanding of underlying material and device physics. Ambipolar OFETs also enable new device applications such as complementary-like circuits made from organic materials.

The goal of the research proposal is the development of organic light emitting optoelectronic transistors. A key target will be the introduction of ambipolar materials in the device structure. Not only intrinsic charge transport properties of organic semiconductors but also the influence of functional insulators as gate dielectrics on the electroluminescence efficiency will be studied. The first phase of the project is devoted to screening of existing as well as development of new functional gate dielectrics suitable for fabrication of light emitting field effect transistors (LFETs). In the second phase, selected systems with ambipolar charge transport properties will be optimized in respect to control and preferentially to balance the mobilities of the charge carriers of both signs, holes and electrons. As the project makes progress, we will concentrate on the studies of charge carrier recombination within the transistor channel that can result in light emission. Several contributions to the electroluminescent efficiency, such as the role of gate dielectrics, the role of injecting electrodes and the proper choice of organic semiconductors with respect to its electronic energy levels will be investigated. For a deeper understanding of the device physics, we will combine the experimental results with theoretical models. Such a light emitting devices with a proper control of ambipolar charge injection may be a step towards the development of organic lasers. In addition to light emission, ambipolar OFETs also offer good opportunity to compare electron versus hole mobilities in a given material under the same experimental conditions and to assess their dependence on electric field, temperature, and charge carrier density. These investigations are important for a deeper basic understanding of underlying material and device physics. Ambipolar OFETs also enable new device applications such as complementary-like circuits made from organic materials.