Design of conjugated molecular materials for optoelectronics

Fluorescent metal complexes and dimers have been synthesized and used for organic light-emitting diodes. The metal complexes with conjugated molecular ligands have strong photoluminescence, and showed bright emission of over 10 000 cd m(-2) in bilayer electroluminescent (EL) cells. The EL cell structure was [transparent anode/hole-transport layer/emitting layer/cathode]. The newly synthesized pyrazoline dimers are also highly fluorescent, and they have hole-transport tendency. Therefore, another type of structure [transparent anode/emitting layer/electron-transport layer/cathode] was applied to get emission from the pyrazoline derivatives. As a result, one pyrazoline derivative showed bright blue EL of 1700 cd m(-2) at the maximum when it was combined with an oxadiazole electron-transport material.