Printable opto-electronic devices using guest host systems

The basic idea of the proposal is the matrix dependent emission behaviour of organometallic compounds in polymer blends. The so called guest host systems are blends of one or more dyes in polymers and can be integrated in solar cells, field effect transistors, opto-electronically modulators and light emitting diodes. Polymer light emitting diodes (PLEDs) are large area, light weight thin film devices converting electricity to light based on electroluminescence. Applications such as monochrome displays were fabricated using semiconducting polymers, first. Many of them are now commercially available. A new focus of research is to generate white light by the superposition of blue, green and red emission using semiconducting polymers. The introduction of LEDs as sources of light for general lighting applications is a very promising idea, because they are energy efficient and environmentally friendly devices. LEDs based on organic and polymer materials can be fabricated using low cost technologies and the devices operate at very low driving voltages. They offer the freedom in shape, substrate combinations and fully tunability in brightness and colour, which opens new design possibilities for backlighting, signalling, emergency lighting etc. In the long term LEDs based on organic and polymer have the potential to replace currently used lighting sources, when they can compete against traditional ones in terms of efficiency and remain still low cost products. The submitted proposal is the first step towards reaching this goal at the host institute, LIOS, which offers one of the world leading scientific platforms for developing solution processable devices. To reach this challenging target, we will develop organic/inorganic material combinations using e.g. inorganic quantum dots or/and organo-metallic phosphorescent dyes as guests in polymer matrices. Fundamental aspects of guest/host interactions on the molecular scale and their consequence on the device properties will be studied in detail. Research in parallel will be focus on the most suitable device structure and cost effective processing technology. Thereby, the knowledge generated for the enhancement of the device performance on purely polymer based LEDs will be transferred for the optimization of white emitting diodes. New strategies including inorganic materials in polymer hosts to optimize the device properties in terms of colour appearance, stability as well as efficiency will be generated.