Effect of electronic nature of emission layer materials on emission region in organic thin-film electroluminescent devices

Effect of electronic nature of emission layer materials on emission region in organic thin-film electroluminescent devices is described. It was found that emission was mainly located at the side of anode in the single-layer EL device with the emission layer material which had electron injection/transport capability, in contrast, emission occurred through the emission layer in the single-layer device with that allowed the injection and transport of both electrons and holes.