A Rapid, LowCost, and Scalable Technique for Printing StateoftheArt Organic FieldEffect Transistors

© 2016 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim (1 of 7) 1600090 wileyonlinelibrary.com library of known materials that have been employed as active components in OFETs, and some of them meet the desired requirements for low-cost applications. [ 2,3 ] Now, the challenge lies in engineering processing techniques that could give rise to highly crystalline and homo genous semiconducting fi lms potentially resulting in reproducibly high mobility devices. [ 4–6 ] To make organic electronics competitive with their inorganic counterparts and to promote a competitive market entry, such techniques must be simple, cheap, and compatible with upscaling and high throughput processes such as roll-to-roll. In the last few years, exciting advances have been achieved in this direction and OFETs fabricated utilizing different solution deposition techniques have been reported exhibiting impressive mobility values. [ 7–20 ] However, not all these techniques are scalable and some of them require additional crystallization steps (i.e., vapor or temperature annealing processes). Importantly, most reported processing techniques are not universal as they are often adapted for a particular organic semiconductor. Recently, we reported a solution-shearing technique, namely bar-assisted meniscus shearing (BAMS), of an organic semiconductor blend based on the small semiconducting molecule dibenzo-tetrathiafulvalene (DB-TTF) and the insulating polymer polystyrene (PS). This technique resulted in highly crystalline thin fi lms that showed ideal OFET characteristics. [ 21,22 ] The question raised at this point was if the BAMS technique could be extended to other organic semiconductors. Here, we report on the fabrication of OFETs employing blends of four benchmark organic semiconductors with PS and we demonstrate that applying the same formulation and experimental conditions for printing them, highly reproducible and uniform crystalline fi lms exhibiting high OFET performance are successfully achieved. We note that the mobility values achieved here are not the highest reported for the studied materials, however, they are state-of-theart values and could be regarded as exceptional considering the low cost and fast speed of the fabrication process involved here.