Gravure printed flexible small-molecule organic light emitting diodes

Small-molecule based flexible organic light-emitting diodes (SMOLEDs) were fabricated by gravure printing. In order to modify rheological properties of the functional ink, the green emitter was embedded into an ultrahigh molecular weight polystyrene (UHMW-PS) matrix. The viscosity of the ink was characterized as a function of the small molecule: UHMW-PS weight ratio and solvent type. The gravure printed SMOLEDs exhibited a maximum luminance of 850 cd m(-2), a maximum efficiency of up to 7.7 cd A(-1), and turn on voltage of similar to 3.5 V. The gravure printed SM: UHMW-PS device exhibits similar to 67% higher luminance efficiency comparing to the spin-coated pristine SM device. (C) 2013 Elsevier B. V. All rights reserved.