Study of charge conduction in a poly(p-phenylenevinylene) derivative carrying an electron-transporting moiety

Recently, we have reported transient electroluminesence (EL) measurements i n an organic light-emitting diode based on a poly(p-phenylenevinylene) (PPV ) derivative carrying an electron-transporting moiety, poly[(2-(4-biphenyl) -5-(4-tert-butylphenyl)-1,3,4-oxdianzole)-p-phenylenevinylene] (PPPDPV), in order to investigate the mechanism of the enhanced external quantum effici ency. In this work, we have carried out J-E (I-V) characteristics measureme nts in EL devices based on PPV and PPPDPV, respectively, which revealed a s pace-charge limited conduction (SCLC) with exponential trap distribution me chanism in both. The trap densities of majority carrier were calculated fro m the J-E (I-V) curves and were compared with the EL external quantum effic iencies.