Fabrication of Ordered Array of Tips-pentacene Micro- and Nano-scale Single Crystals

As an important type of organic semiconductors, organic small molecule crystals have great potential for low-cost applications such as plastic solar cells (PSC), organic light emitting diodes (OLED) and organic field-effect transistors (OFET). Among numerous molecular crystals, 6, 13-Bis(triisopropylsilylethynyl)pentacene (Tips-pentacene) has aroused much attention because it combines good solubility in common solvents and strong π-π stacking from self-assembly. However, the inability to achieve ordered array of Tips-pentacene prevents the fabrication of high-performance organic integrated circuits. In this work, two new fabrication methods to pattern Tips-pentacene micro- and nano-scale single crystals are proposed. Both methods are facilitated by nanofabrication techniques such as nanoimprint and photolithography. In the first method, the surface of a silicon substrate is treated by surfactant coating and Tips-pentacene single crystals are deposited in squared patterns. In the second method, we made an ordered array of Tips-pentacene single crystals confined in Teflon-AF patterns. In both techniques, the effects of solvent type, processing temperature and template pattern size on crystal morphology and size are systematically studied