Patterning cathode for organic light-emitting diode by pulsed laser ablation

In this paper, nanosecond pulsed laser is introduced as a method to pattern the metal cathode of organic light-emitting diodes (OLEDs) without shadow mask or cathode separator. This method can selectively ablate away cathode metal without damage on the underlying indium tin oxide anode or the surrounding organic layers. The width and morphology of laser ablation trenches were studied as a function of energy fluence as well as pulse number of laser. The uniform ablation trench was obtained with 16 pulses at the laser fluence of 0.15 J/cm2. It was found that the characteristics of OLED prepared with laser ablation under optimum ablation process were almost the same with that of OLEDs prepared with other two patterning methods.