Studies on Printing Inks Containing Poly[2-methoxy-5-(2-ethylhexyl-oxyl)-1,4-phenylenevinylene] as an Emissive Material for the Fabrication of Polymer Light-Emitting Diodes by Inkjet Printing

Abstract

Three solvent systems, chlorobenzene (ink 1), chlorobenzene/o-dichlorobenzene (ink 2) and chlorobenzene/ tetrahydronaphthalene (ink 3), were compared as printable inks for the fabrication of polymer light-emitting diodes (PLEDs) using poly[2-methoxy-5-(2-ethylhexyl-oxyl)-1,4-phenylenevinylene (MEH-PPV) as an emissive material and an inkjet printer (Fujifilm Dimatix DMP-2831). Ink 1 clogged the printer’s nozzle and gave non-uniform film. Inks 2 and 3 were used to fabricate PLEDs with ITO/PEDOT:PSS/MEH-PPV/LiF/Al configurations. The best performance (turn-on voltage, 3.5 V; luminance efficiency, 0.17 cd/A; luminance, 1,800 cd/m) was obtained when ink 3 was used to form the emissive layer (thickness, 49 nm), attributable to the better morphology and suitable thickness of the MEH-PPV layer.