Study on the meniscus-guided solution shearing process with microfluidic channel embedded

Abstract

Recently, organic semiconductors that can be used in flexible and stretchable electronic devices have been researched as next-generation semiconductors that can replace conventional silicon-based semiconductors. One of the greatest advantages of organic semiconductors is that they can be fabricated on flexible substrates such as plastic substrates and the process that makes this possible is solution-based coating techniques. This process has the advantage of producing cost-effective, energy-efficient, large-area thin film compared to top-down manufactu ring the existing inorganic semiconductor, so related research has been actively studied. However, the device performance is significantly affected by the morphology, crystallinity, crystal orientation, molecular packing. Among the solution-based process, Meniscus-guided coating techniques have been developed because the solution evaporates only in the meniscus, which is the interface between liquid and air. So far, many studies have focused on device performance improvements and even though sufficient performance is achieved, the device-to-device variation makes it difficult to commercialize. Herein, we form very uniform organic thin films through microfluidic channel embedded solution shearing. The uniform morphology, crystallinity and crystal orientation of thin film are formed through the microfluidic channel that can continuously supply the solution during solution shearing and the herringbone pattern channel which can maximize the mixing effect simultaneously. In addition, the flows in the microfluidic channel were predicted and analyzed by simulation. Though the herringbone patterned channel that can create the environment in the channel such as the most turbulent-like flow, the characteristics of the organic thin-film devices are improved. As such, the microfluidic channel based solution shearing method can form uniform thin films, which will greatly help industrialization.