Efficient Fullcolour Light-Emitting Devices and Lasers with Polyphenyls
Soluble and stable polyparaphenylene-type ladder polymers with an extraordinary high degree of intrachain order and exceptionally low concentration of defects in the electronic structure belong to the class of best defined conjugated low-dimensional organic semiconductors currently available. Parahexaphenyl, the highly stable oligomer of polyparaphenylene, can be synthesized in the form of single crystals, disordered thin films and highly ordered epitaxially grown thin films. We present and discuss results on the optical and optoelectronic properties of these polyparaphenylene systems.
We demonstrate the fabrication and characterization of highly efficient red-green-blue (RGB) and white light emitting devices with these electro-active materials. This RGB-devices are fabricated based on a new technique, which allows the realization of fullcolour flat panel displays. The brightness of such RGB emitting devices is higher than 1000 cd/m2 (for the green device), comparable to that of fluorescent tubes. Using this new technique, we are able to produce devices having any desired emission colour in the visible and near infrared spectrum.
A high photoluminescence quantum yield and a good environmental stability of the active oligomer or polymer materials, besides many other device parameters, are very important to achieve competitive operation lifetimes of these new organic electroluminescence devices.
Photoexcitation experiments on polyparaphenylenes reveal their high photoluminescence quantum yield and the perspective for being true candiates as solid-state polymer-laser materials due to their pronounced signature of blue-green stimulated emission. We present blue-green laser action in polyparaphenylene-type ladder polymer.
KeywordsExcitation Energy Transfer Emission Color White Light Emission Threshold Electric Field Good Environmental Stability
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