Direct patterning of silver electrodes with 2.4μm channel length by piezoelectric inkjet printing.

The control of channel length is of great significance in the fabrication of thin film transistors (TFTs) with high-speed operation. However, achieving short channel on untreated glass by traditional piezoelectric inkjet printing is problematic due to the impacting and rebounding behaviors of droplet impinging on solid surface. Here a novel method was proposed to obtain short channel length on untreated glass by taking advantage of the difference in the retraction velocities on both sides of an ink droplet. In addition, droplets contact mechanism was first introduced in our work to explain the formation of short channel in the printing process. Through printing droplets array with optimized drop space and adjusting appropriate printing parameters, a 2.4μm of channel length for TFT, to the best of our knowledge, which is the shortest channel on substrate without pre-patterning, was achieved using piezoelectric inkjet printing. This study sheds light on the fabrication of short channel TFT for large size and high-resolution displays using inkjet printing technology.