Edgar Kluge

Development of high performance PPVs: implications of the polymer-microstructure

Poly(p-phenylene vinylene)s (PPVs) are promising materials for optoelectronic applications, especially for displays based on polymer light emitting diodes (PLEDs). We report here our findings concerning defect structures in this class of materials and the implications of the discovered irregularities on important material properties, that is, the operational life in a PLED. Recent improvements, which were deduced from this findings, are presented: optimized PPVs with a lower amount of defects result in a strong increase of operational lifetime.

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.

51.1: Invited Paper: Polymers for Efficient OLEDs

Polymer light-emitting diodes (PLEDs) and displays based on polymer technology have made dramatic progress during the last years. In particular, efficiency and device lifetime have improved to such a significant extent that first products will commercialized within this year. We report here on the technical status of materials and devices upon which this success is based. Efficiency and especially operational stability are now at a level which easily meets the requirements for a variety of applications, namely power efficiencies are well above 10 lm/W, operational lifetimes are exceeding 20000 hours at display brightness levels and room temperature). This progress has been achieved by the careful analysis of failure mechanisms and the systematic improvement of materials. The first products, i. e. back-lights (for LCD-displays), segmented displays, and finally passive-matrix-addressed low-information-content (LIC) graphical displays are described. Light emitting polymerss are now manufactured on industrial scale under high purity conditions; filling and packaging is done under a class 10 clean room condition. For details see H. Becker Paper 46.1.