Effect of Ag cathode deposition rate on the performance of organic light-emitting diodes

The effect of deposition rate of silver (Ag) cathode on the device performance of organic light-emitting diodes (OLEDs) has been investigated. The leaky current before the turn-on of devices was observed in the samples that have the Ag cathode deposited at relatively low rate (less than 0.5 Å/s), and their emission efficiencies were found to be undesirably inconsistent. These issues were not observed in the samples that have Ag cathode deposited at higher rate (>1.0 Å/s). Here we show that the pixel-to-pixel uniformity of OLEDs employing Ag cathode can be simply improved by depositing the cathode at high rate, since the rapid deposition suppresses the Ag diffusion into underlying organic layer.