Organic semiconducting layers fabricated by self-metered slot-die coating for solution-processable organic light-emitting devices
We present the results of a study of flat, uniform, and stripe-patternable organic semiconducting layers produced by a slot-die coating method using a self-metered coating mode with blended solutions for the fabrication of bright, efficient, and large-area organic light emitting devices (OLEDs). It is shown that the self-metered slot-die coating process can produce high quality, homogeneous, and stripe-patterned thin films using the downstream meniscus of a blended solution, which can be controlled by adjusting the coating parameters of the capillary number of the coating solution by varying the gap height and coating speed. It is shown that very bright and efficient OLEDs (peak brightness ∼50 000 cd m−2 with maximum efficiencies of ∼29 cd A−1 and ∼14 lm W−1) were successfully demonstrated by manipulating the slot-die coated hole-injecting and electroluminescent layers that contained the phosphorescent Ir complex. In view of these results, we believe that the fabrication of organic semiconducting layers using the self-metered slot-die coating process is a promising new technique for high-throughput manufacturing such as via the roll-to-roll process.