Soft fabric-based flexible organic light-emitting diodes

We reported the first organic light-emitting diodes (OLEDs) on actual soft fabrics that can be used for a wearable display. Polyurethane (PU) and poly(vinyl alcohol) (PVA) layers, which only degrade slightly the flex stiffness of bare fabrics due to their ductile characteristics, were used as planarization layers via a simple fabrication process involving lamination and spin-coating. Therefore, many of the mechanical characteristics of the bare fabric substrates were retained in the planarized fabric substrates. Non-inverted top-emitting OLEDs, designed by considering the optical microcavity effects, were fabricated on a planarized surface by thermal evaporation. The fabricated OLEDs on soft fabrics showed a high current efficiency of around 8 cd/A, reliability during a 1000 cycle bending test with a bending radius of 5 mm, and clear green emission up to an emission angle of 70 degrees. Consequently, we developed high-performance OLEDs on very similar to real fabric via a simple universalized fabrication method. (C) 2013 Elsevier B. V. All rights reserved.