There have been only a limited number of reports on solution-processed n-channel organic thin-film transistor (OTFT) devices with high levels of electrical performance, because the material design process for the n-type organic semiconductors are relatively difficult compared to p-type semiconductors, and further chemical modification of the functional groups are required. As a result, the development of soluble n-type organic semiconductors with high carrier mobilities has remained a challenge. Our work addresses this by introducing a novel molecular design to realize soluble n-type organic semiconductors with high electron mobilities, through the simple substitution of trifluoromethyl or trifluoromethoxy groups at meta-positions support sufficient solubility, creating suitable LUMO energy levels and high crystallinity. These newly designed benzobisthiadiazole (BBT)-based molecules showed electron mobilities as high as 0.61cm 2 V −1 s −1 in solution-processed OTFT devices. As a practical application in printed electronics, we demonstrated an organic complementary inverter circuit with OTFT devices using the developed soluble organic semiconductors. Due to their high solubility level and superior electrical properties compared to common para-derivatives, the utilization of meta-substituents is a new strategy for the design of soluble organic semiconductors in the field of OTFT device fabrication.

Benzobis(thiadiazole) derivatives showed a large diffusion coefficient between the molecules located in the co-planar and the standard π–π stacking directions.