Printing Poly( p-phenyleneethynylene) PLEDs.

Gravure printing of functional thin-film layers of side-chain-substituted poly( para-phenyleneethynylene)s (PPEs) is reported. Rheological properties of PPEs in combination with the Hansen solubility model allowed the formulation of enhanced single-component inks. Layer evaluation is performed with reflectometric thin-film recordings in an optical setup for laterally resolved large-area investigation using imaging color reflectometry. An organic light-emitting diode in a simple glass/indium tin oxide/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/PPE/LiF-Al stack was gravure-printed from the improved ink showing excellent luminance (542 cd m-2, U = 11.5 V) for this polymer class.