Channel-restricted meniscus self-assembly for uniformly aligned growth of single-crystal arrays of organic semiconductors

Abstract Organic semiconductor single-crystal (OSSC)-based field-effect transistors (FETs) with high mobility and small device-to-device variation enable OSSCs to be adapted for practical applications. Research attention has recently been focused on developing simple ways of fabricating large-area OSSC arrays by means of solution-coating techniques. However, the lack of control of the meniscus front, where the nucleation and growth of organic crystals occur, leads to inconsistent crystal alignment and consequently induces large variation in device performance. Here, we propose a universal strategy, termed the channel-restricted meniscus self-assembly (CRMS) method to fabricate ultrahigh-mobility, uniform OSSC arrays. The microscale photoresist channels used in this method produce a confinement effect to reduce the size of the meniscus, enabling the homogeneous nucleation of OSSCs at the meniscus front. Meanwhile, the dip-coating process ensures consistent molecular packing in the OSSCs and thus guarantees their highly uniform electrical properties. Using 2,6-diphenylanthracene as an example, wafer-scale (>2 inch) OSSC arrays with very small size variations (10%) are successfully prepared, which is very difficult to achieve by using the previously reported methods. As a result, field-effect transistors (FETs) based on the OSSC arrays show a high average hole mobility of up to 30.3 cm2 V−1 s−1 with good uniformity among devices. This method is general for the growth of various OSSC arrays, facilitating the applications of OSSCs in large-area, high-performance organic electronic devices.