Patterning of organic semiconductor crystal arrays via microchannel-assisted inkjet printing for organic field-effect transistors

Abstract

Inkjet printing technique provides a low-cost way for large-area construction of the patterned organic semiconductors toward integrated organic electronics. However, because of a lack of control over the wetting and dewetting dynamics of organic inks, inkjet-printed organic semiconductor crystals (OSCCs) are frequently plagued by the ‘coffee ring’ effect and uncontrollable growth process, leading to an uneven crystal morphology and disordered orientation. Here, we report a universal microchannel-assisted inkjet printing (MA-IJP) method for patterning of OSCC arrays with ordered crystallographic orientation. The micro-sized channel template not only provides a unidirectional capillary force to guide the wetting process of organic inks, but also confines the evaporation-induced dewetting behavior, enabling the long-range ordered growth of OSCCs. The patterned 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) crystals present one-dimensional structures with a pure (010) crystallographic orientation. The 7 × 7 discrete organic field-effect transistor array made from the patterned C8-BTBT crystals exhibits a high average mobility up to 3.23 cm2 V−1 s−1 with a maximum mobility of 5.36 cm2 V−1 s−1. Given the good generality of the patterning process and high quality of the obtained OSCC crystal array, it is anticipated that our MA-IJP approach will constitute a major step toward integrated electronic and optoelectronic devices.