ITO films realized at room-temperature by ion beam sputtering for high-performance flexible organic light-emitting diodes

Université de Limoges, Faculté des Sciences et Techniques, CNRS, UMR 6172, Institut de Recherche XLIM, Département MINACOM, 123 Av. Albert Thomas, 87060 Limoges Cedex, France

Corresponding author: bruno.lucas@unilim.fr

Received: 5 January 2006
Revised: 31 January 2006
Accepted: 2 February 2006
Published online: 24 June 2006

Abstract

Indium-tin oxide (ITO) thin layers are obtained by an IBS (Ion Beam Sputtering) deposition process. We elaborated ITO films on flexible substrates of polyethylene terephthalate (PET), under soft conditions of low temperatures and fulfilling the requirements of fabrication processes of the organic optoelectronic components. With a non thermally activated (20 °C) ITO deposition assisted by an oxygen flow (1 cm³/min), we got an optical transmittance of 90% in the visible range, a resistivity around 10⁻³ Ω.cm and a surface roughness lower than 1.5 nm. Thus we realized flexible organic light-emitting diodes (FOLEDs) with good performances: a maximum luminance of 12000 cd/m² at a voltage of 19 V and a maximum luminous power efficiency around 1 lm/W at a voltage of 10 V (or a maximum current efficiency of 4 cd/A at 14 V) for the (PET(50 μm)/ITO(200 nm)/TPD(40 nm)/Alq3(60 nm)/Ca/Al) structure.