Microfluidic white organic light-emitting diode based on striped fine microchannels for greenish blue and yellow liquid emitters

We demonstrated a microfluidic white organic light-emitting diode (microfluidic WOLED) with integrated patterns of greenish-blue and yellow. Sub-100-µm-wide microchannels were alternately filled with greenish-blue and yellow liquid emitters to generate the patterns. 1-Pyrenebutyric acid 2-ethylhexyl ester (PLQ) was used as the greenish-blue emitter, while 2,8-di-tert-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyltetracene (TBRb)-doped PLQ was applied as the yellow emitter. The microfluidic WOLED exhibited white electroluminescence (EL) emission under 100V, which covers the broad emission band ranging from 420 nm to 750 nm. The EL emission occurred from the simultaneous greenish-blue and yellow emissions. The white emission with Commission Internationale de l'Eclairage (CIE) color coordinates of (0.40, 0.42) was obtained, which corresponds to warm-white light. Our microfluidic WOLED technology opens up new possibilities for not only sub-pixels of microdisplays but also lightings.