Amir Parham

Light-emitting polymer materials for full-color displays

In the last few years, industrial research into materials fulfilling the needs of the maturing OLED display industry has intensified considerably. A first generation of polymers (phenyl-PPVs) is now being commercially exploited in first monochrome polymer LED displays. Nevertheless, due to market interest, there is a huge demand for materials for full-color OLED displays. After giving some initial results on our work in this field at last years SPIE, we will report on the progress in the development of polymers for red, green, and blue emission. Our main focus here lies on the improvement of the properties of various polymers derived from the spiro-bifluorene core. Depending on the color, the main issues vary strongly: Whereas e.g. for BLUE materials, efficiency, color coordinates, and processibility fulfill already commercial demands, operational lifetime still needs to be improved strongly. For RED materials, in contrast, the operational lifetime is already excellent, whereas the efficiency and the driving current still need to be improved. For GREEN acquiring saturated emission, whilst maintaining the other properties (high efficiency, long operational lifetime), is still challenging. Also, we will report on advances in full-color patterning, especially techniques based on Ink-Jet Printing.

Developments in polymer materials for electroluminescence

In the last few years industrial research into materials fulfilling the needs of the fledgling OLED display industry have intensified considerably. At Covion we have developed a range of polymers based on phenyl-PPV derivatives which are now being commercially exploited in the first polymer LED applications. These materials have been developed systematically with the demanding requirements of the devices (e.g., high efficiency and lifetime) and the industrial applicability (e.g. processibility, reproducibility and reliability of supply) in mind. However due to market forces, such as the introduction of 3rd generation mobile communication technology, there will be an immediate demand for materials for full color OLED displays. In this paper we will report on progress in the development of Red, Green and Blue (RGB) materials at Covion. The requirements for the different colors vary depending on band gap (amongst others) and therefore the challenges for each color are different. The experience gained in understanding the important structure-property relationships in the phenyl-PPVs has been used to develop these new RGB materials.