Effective design of blue organic electroluminescent devices by introducing functional monomeric layers

Blue organic electroluminescent devices (OELDs) of a multi-layered structure were fabricated and their device performance was investigated. A distyryl biphenyl arylene derivative was synthesized as a blue emitting material. To improve thermal stability of the monomeric hole-transporting emissive material, poly(bisphenol A-co-4-nitrophthalic anhydride-co-l,3-phenylene diamine) was used as a matrix. For more effective design of the devices, poly(styrene sulfonate) doped poly(3,4-ethylenedioxythiophene),2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (Bathocuproine) and tris(8-quinolinolato)aluminum (Alq3) were introduced as a buffer layer, a hole-blocking layer, and an electron-injection layer, respectively. The OELDs showed bright green color when Bathocuproine layer was not applied.