Self-assembly of semiconductor/insulator interfaces in one-step spin-coating: a versatile approach for organic field-effect transistors

Self-assembly of interfaces is of great interest in physical and chemical domains. One of the most challenging targets is to obtain an optimal interface structure showing good electronic properties by solution-processing. Interfaces of semiconductor/semiconductor, semiconductor/insulator and insulator/insulator have been successfully manipulated to obtain high-performance devices. In this review we discuss a special class of interface, semiconductor/insulator interface, formed by vertical phase separation during spin-coating and focus on the versatile applications in organic field-effect transistors (OFETs). The formation of such an interface can be finished within tens of seconds and its mechanism is related to the materials, surfaces and dynamics. Fascinatingly, such self-assembly could be used to simplify the fabrication procedure, improve film spreading, change interfacial properties, modify semiconductor morphology, and encapsulate thin films. These merits lead to OFETs with high performance and good reliability. Also, the method is very suitable for combining with other solution-processed techniques such as patterning and post-annealing, which leads to facile paper electronics, in situ purification and single crystal formation. Research on this topic not only provides an in-depth understanding of self-assembly in solution processing, but also opens new paths towards flexible organic electronics.