Printing technology based on isotropic liquid phase of naphthalene diimide derivatives for n-type organic transistors

Abstract

Abstract Solution processes are well suited for large-scale production of thin films of organic active layers in transistors. However, environmentally hazardous chlorine-based solvents are required for conventional solution processes. Here we introduced a new wet-process approach, without the use of toxic solvents, for creating isotropic phases of several naphthalene tetracarboxylic acid diimide derivatives substituted at the N and N′ positions with long alkyl chains of varying lengths (NTCDI-Cn). Thin films of NTCDI-Cn were prepared by this process, the dependence of the device performance on the thickness of the thin films and the length of the NTCDI-Cn alkyl chains was investigated, and the process was optimized. The devices of NTCDI-Cn exhibited a relatively high electron mobility (∼0.1 cm2/V), and a maximum electron mobility of 0.38 cm2/V was obtained from the 50-nm-thick NTCDI-C13 TFT.