The enhancement of electroluminescence efficiency by molecular doping

Abstract

We report on the investigation of electroluminescence (EL) for a dye-doped polymer. This doping system consists of main chain conjugated poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and highly fluorescent dye rubrene. We fabricated many EL samples of various doping ratios due to the good solubility of rubrene and MEH-PPV in organic solvents. Low operation voltage and high EL efficiency were obtained simultaneously in the molecularly doped system. We made EL cells having an emission efficiency 10 times higher than that of an undoped MEH-PPV diode with nearly the same turn-on voltage. (C) 1997 Elsevier Science S.A.