Fabrication and characterization of large-area flexible microfluidic organic light-emitting diode with liquid organic semiconductor

• We developed a large-area flexible microfluidic OLED.
• A flexible SU-8 microchannel structure was formed on the ITO-patterned PET by the newly proposed belt-transfer exposure.
• Flexible electro-SU-8-microchannels with a liquid emission layer were fabricated.
• Fabricated large-area flexible microfluidic OLED operated successfully in both flat and curved states.

We propose simple and high-throughput fabrication of large-area flexible microfluidic organic light-emitting diodes (microfluidic OLEDs). Flexible electro-SU-8-microchannels with a liquid emission layer were fabricated by the following four steps: (a) screen printing for transparent electrodes, (b) novel belttransfer exposure for SU-8, (c) heterogeneous low-temperature bonding using self-assembled monolayers (SAMs), and (d) injecting a liquid emitter into the microchannels. 1-Pyrenebutyric acid 2-ethylhexyl ester (PLQ), which is on of liquid organic semiconductors, was used as a liquid emitter. The liquid emitter successfully filled the flexible microchannels, and electroluminescence was obtained both in flat and curved states. The proposed microfluidic OLED is applicable for future flexible posters or displays, and can be adopted around curved surfaces.