Fabrication of flexible organic top-emitting devices on steel foil substrates

A flexible organic light-emitting diode (FOLED) was fabricated on a steel foil. Stainless steel foil, spin-coated polyvinyl acetate (PVA) and silicon oxide were used as a flexible substrate, an insulating planarization layer and a buffer layer, respectively. Patterned indium tin oxide (ITO) was sputter-deposited on the buffer layer to form an anode. N,N'-bis-(1-naphthl)-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB) and tris(8-quinolinolato) aluminum (Alq(3)) were used as a hole-transporting layer and a light-emitting/electron-tran sporting layer, respectively. A thin samarium layer was deposited on the organic stack to serve as a semitransparent cathode. The turn-on voltage of the resulting FOLED was 3 V, and the light-emitting efficiency reached 0.56 cd/A. The FOLED was shown to bend substantially without incurring detectable degradation. (C) 2003 Elsevier B.V. All rights reserved.