Multi-color microfluidic organic light-emitting diodes based on on-demand emitting layers of pyrene-based liquid organic semiconductors with fluorescent guest dopants

• Published in: Sensors and actuators. B, Chemical Vol. 207; pp. 481 - 489
• Main Authors: Kasahara, Takashi, Matsunami, Shigeyuki, Edura, Tomohiko, Ishimatsu, Ryoichi, Oshima, Juro, Tsuwaki, Miho, Imato, Toshihiko, Shoji, Shuichi, Adachi, Chihaya, Mizuno, Jun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-02-2015
• Subjects: Electro-microfluidic; Emitters; Energy transfer; Fluorescence; Indium tin oxide; Liquid host; Liquid OLEDs; Liquid organic semiconductor; Liquids; Luminance; Microfluidic OLEDs; Microfluidics; Organic light-emitting diodes; Organic semiconductors; Liquid organic semiconductor; Electro-microfluidic; Liquid host; Liquid OLEDs; Energy transfer; Microfluidic OLEDs
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2014.09.101

In this study, we propose on-demand multi-color microfluidic organic light-emitting diodes (microfluidic OLEDs) using fluorescent guest emitter-doped liquid organic semiconductors. We use 1-pyrenebutyric acid 2-ethylhexyl ester (PLQ) not only for a greenish-blue liquid emitter, but also for a liquid host. 5,12-Diphenyltetracene (DPT), 5,6,11,12-tetraphenyltetracene (rubrene), and tetraphenyldibenzoperiflanthene (DBP) are doped into PLQ to obtain green, yellow, and red liquid emitters, respectively. Single-micrometer-thick SU-8-based microchannels sandwiched between an indium tin oxide (ITO) anode and a 3-aminopropyltriethoxysilane (APTES)-modified ITO cathode are fabricated on a glass substrate using photolithography and heterogeneous bonding techniques, and emitting layers are formed on-demand by simply injecting liquid emitters into the target microchannels. The microfluidic OLEDs with liquid emitters successfully exhibited multi-color electroluminescence (EL) emissions. Furthermore, the maximum luminance reached 26.0cd/m2 at 61V for 2.5-μm-thick microfluidic OLED with PLQ, and the decreased EL luminance was recovered by replacing the degraded emitting layer with a fresh liquid emitter. We expect that on-demand multi-color EL emissions and refreshable luminance features of the proposed microfluidic OLEDs will be highly promising technologies for future long-life light-emitting device applications.