Patterning process of ink-jet printed 6,13-bis(triisopropylsilylethynyl) pentacene layer using bank structures for organic thin film transistors

Abstract

A layer of 6,13-bis(triisopropylsilylethynyl) pentacene(TIPS-pentacene) organic thin film transistors (OTFTs) deposited by an ink jet printer was patterned using bank structures. Normally, banks degrade the performance of OTFTs because ink adhering to the sidewalls of the bank disrupts the formation of crystal grains, lowering mobility. An appropriately designed bank structure, which had only two photo-resist sidewalls perpendicular to the channel direction of the OTFTs, produced a mobility of the 0.23±0.05cm2/V·s, comparable to 0.25±0.09cm2/V·s of OTFTs produced without banks. The minimum thickness of the TIPS-pentacene layer needed to achieve high mobility was determined to be about 20nm. A modified bank structure with a splitter bar in the middle of the open bank was also developed to simultaneously fabricate two OTFTs by jetting a single drop on the splitter. The mobilities of the two OTFTs were 0.24±0.04cm2/V·s and 0.28±0.09cm2/V·s, respectively.