Plasma damage-free deposition of Al cathode on organic light-emitting devices by using mirror shape target sputtering

We report on the fabrication of plasma damage-free organic light-emitting devices (OLEDs) by using a mirror shape target sputtering (MSTS) technique. It is shown that OLEDs with Al cathode deposited by the MSTS show much lower leakage current (1 × 10^-5 mA/cm²) at reverse bias of -6 V, compared to that (1 × 10^-1 -∼ 10^-2 mA/cm² at -6 V) of OLEDs with Al cathodes grown by conventional dc magnetron sputtering. This indicates that there is no plasma damage, which is caused by the bombardment of energetic particles. This suggests that MSTS could be a useful plasma damage-free and low-temperature deposition technique for both top- and bottom-emitting OLEDs and flexible displays.