Perylenediimides with electron transport moieties for electroluminescent devices

Low molecular weight and polymeric imides are synthesized by attaching perylene units as substituents or by incorporating in aromatic main chain copolymers to achieve high photoluminescent efficiency. In order to improve electron injection and transport properties 1,3,4-oxadiazole comonomers with high electron affinities are used. The best solid state photoluminescence is obtained in copolymers with 0.5 mol% perylene content. The low molecular weight compounds exhibit high electron affinity with LUMO values in the range of -3.9 eV as determined by cyclic voltammetry. Electroluminescent devices with copolymers in PVK blends show characteristic red emission from perylene which is nearly identical with its photoluminescence and the efficiency of this device, ITO/copolymer+PVK blend(100nm)/Al, depends upon the PVK content.