Showa Denko K.K. (SDK) has made remarkable progress in its development of organic electroluminescent (organic EL) device technology based on an innovative singlelayer organic electroluminescent devices based on phosphorescent polymer materials, achieving the world's highest external quantum efficiency of 17% for green light and 16% for blue light, respectively, with durability of 350,000 hours (initial luminance: 100 cd/m2). SDK is also developing a large surface-emission panel based on this polymer technology and will build a trial volume-production line by the middle of this year. Quantum efficiency means the rate at which energy input is finally taken out as light. Theoretically, the maximum quantum efficiency for phosphorescent organic EL device is 20%.

SDK has achieved a breakthrough by developing a new copolymer - in which phosphorescent substance and other materials are mixed - realizing highest-level emissive efficiency in the industry today.

Although low-molecular-weight-compound-based organic EL devices need to be produced at under vacuum, polymer-based organic EL devices can be produced under less expensive, normal conditions. So far, problems with emissive efficiency and durability hampered commercialization efforts. With SDK's proprietary singlelayer organic electroluminescent devices based on phosphorescent polymer materials and cleaning/interface control technology, however, it is now possible to produce high-performance and stable organic EL panels. (Since an organic EL layer of less than 100 nm in thickness is sandwiched between electrodes, the cleanliness of electrode surface and work function largely influence the device performance.) SDK will further improve the technology and aim to place the new product on the market by the end of 2008.

While organic EL devices are generally developed for high-precision display applications, including mobile phones and large-screen TVs, SDK is aiming to develop advertisement and display applications, fully utilizing the advantages of high emissive efficiency, long durability and large area-emission due to the proprietary phosphorescent copolymer. SDK is planning to achieve annual sales of 10 billion from this product in 2010.

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