Large area ITO-free flexible white OLEDs with Orgacon PEDOT:PSS and printed metal shunting lines

Abstract

We demonstrate the feasibility of white organic light-emitting diodes that exclude the transparent conductor indium-tinoxide. Instead, a highly conductive Orgacon^TM PEDOT:PSS material in combination with a metal support structure is used as transparent anode and hole-injection layer. The PEDOT:PSS exhibits a conductivity of 460±20 S/cm and a work function of 5.35±0.05 eV. On ITO-free OLEDs on glass with an active area of ~6 cm² the inclusion of 120 nm thick printed metal lines reduces the variation in brightness from 35% to 20%. The ITO-free concept based on PEDOT:PSS with printed metal structures is scaled up to large flexible OLEDs with a size of 150 cm² on a heat-stabilized Teonex® Polyethylene Naphtalate foil. The voltage distribution across the various electrodes was verified by a finite element model, allowing a prediction of the OLED brightness and homogeneity over large areas.