Materials and devices for polarized electroluminescence

The engineering of new electronic and photonic devices requires materials w ith unique properties. To find these, scientists increasingly harness the v ersatility of organic chemistry. Three key advantages of organic semiconduc tors over their inorganic counterparts are a direct result of the chemical diversity of the molecular world: Processability from solution, chemical ba ndgap tuning, and the ability to self-organise. The first two advantages ar e now widely exploited, but the third has yet to receive more attention. On e area where the use of self-organising materials for organic optoelectroni cs is comparatively advanced is the held of polarized electroluminescence ( EL). A polarized lightsource would lend itself well to use as a backlight f or liquid crystal (LC) displays. In this contribution, we report on the dev elopment of polarized lightsources based on conjugated LC polymers. This ap proach is now fairly advanced, and polarization ratios in excess of 20 have been demonstrated. As an alternative approach, are have recently started t o extend the versatile reactive mesogen concept to organic semiconductors. We report on first results on this new class of materials.