High-performance flexible organic light-emitting diodes using amorphous indium zinc oxide anode

We demonstrate a high-performance flexible organic light-emitting diode (OLED) employing amorphous indium zinc oxide (IZO) anode. The amorphous IZO on flexible polycarbonate (PC) substrate shows similar electrical conductivity and optical transmittance with commercial (ITO) glass, even though it was prepared at < 50 degrees C. Moreover, it exhibits little resistance change during 5000 bending cycles, demonstrating good mechanical robustness. A green phosphorescent OLED fabricated on amorphous IZO on flexible PC shows maximum external quantum efficiency of eta(ext) = 13.7% and power efficiency of eta(p) = 32.7 lm/W, which are higher than a device fabricated on a commercial ITO on glass (eta(ext) = 12.4% and eta(p) = 30.1 lm/W) and ITO on flexible PC (eta(ext) = 8.5% and eta(p) = 14.1 lm/W). The mechanical robustness and low-temperature deposition of IZO combined with high OLED performance clearly manifest that the amorphous IZO is a promising anode material for flexible displays. (c) 2007 The Electrochemical Society.