THE ENHANCEMENT OF ELECTROLUMINESCENCE EFFICIENCY BY MOLECULAR DOPING

We report on the investigation of electroluminescence (EL) for a dye-d oped polymer. This doping system consists of main chain conjugated pol y methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and hig hly fluorescent dye rubrene. We fabricated many EL samples of various doping ratios due to the good solubility of rubrene and MEH-PPV in org anic solvents. Low operation voltage and high EL efficiency were obtai ned simultaneously in the molecularly doped system. We made EL cells h aving an emission efficiency 10 times higher than that of an undoped M EH-PPV diode with nearly the same turn-on voltage. (C) 1997 Elsevier S cience S.A.