Aligned nanowire arrays on thin flexible substrates for organic transistors with high bending stability

Abstract

Flexible organic field-effect transistors (OFETs) are fundamental elements for the development of rollable displays, flexible circuits, and bio-compatible sensors. Although single-crystalline organic nanostructures show great promise for the construction of high-performance OFETs, their applications in flexible devices are rarely investigated due to the large incompatibility with existing processing techniques. Here, we report the fabrication of copper phthalocyanine (CuPc) nanowire (NW) array-based top-gate OFETs on flexible PDMS substrates via an efficient and versatile etching-assisted transfer printing (ETP) method. The thickness dependent bending stability of the OFETs was investigated. It was demonstrated that the device with a thinner substrate thickness possessed a higher bending stability owing to the smaller bending-induced mechanical strain. Also, the bending direction played an important role in determining the bending stability; a higher bending stability was achieved when the bending direction was perpendicular to the NW length direction. We also performed a real-life flexibility test by repeatedly crumpling the device in the palm of the hand, verifying the excellent bending stability and reproducibility of the flexible devices. It is expected that the organic NW array-based top-gate OFETs with high bend stability will have important applications in future flexible electronics.