Research Progress of High-precision Patterns by Directly Inkjet Printing

High-precision patterns have aroused wide attention due to their important applications in high-performance op- tical/electrical devices. By virtue of easy and direct writing of desired patterns, high throughput and low-cost, inkjet printing has become one of the most promising candidates for the manufacture of patterns, compared with conventional approaches such as photolithography, microcontact printing. Various materials can be precisely deposited on target positions. As a pri- mary focus, improving the precision of printed patterns would greatly enhance the performance of the devices. So far, various approaches have been developed for improving the printing precision. Pattern resolution is limited by the volume of jetted droplet and the area of droplet spreading on substrate. Finer resolution can be achieved through reducing the deposition di- mension, i.e. optimization of the chemical composition of ink, chemical/physical modification of substrates, and improve- ment of printing apparatus. Besides, uniform deposition of functional materials is also essential for fabricating high-precision patterns and high-performance devices. Coffee ring is a common phenomenon during the drying process of droplets, which is generated due to the pinning three phase contact line (TCL) and the outward capillary flow in an evaporating droplet. Therefore, homogenous deposition without coffee ring effect can be realized by tuning the capillary flow in the droplet and controlling the movement of the TCL as the droplet evaporating. In this paper, we presented the recent research progress for achieving high-precision patterns by inkjet printing, including minimizing the deposition dimension to improve the resolution and avoiding the coffee ring effect to achieve high uniformity. These reports will probably promote the development of novel and facile method for high-precision inkjet printing. New trends and research perspectives were briefly discussed at the last section of this review.