Solvent Exchange in Controlling Semiconductor Morphology

Abstract: Recent studies in solution processed, small molecular organic semiconductors have reported unparalleled advances in charge carrier mobilities, warranting promising application in organic electronic devices such as organic gas sensors and complimentary circuits. However, the in-solution crystallization of small molecular organic semiconductors has presented specific challenges including crystal misorientation, grain boundary and mobility variation. In this article, we first discuss the effects of these issues on charge transport and highlight the virtues of solvent choices to optimize the semiconductor morphology. Then, we conduct an in-depth review of the miscellaneous solvent exchange methods to effectively palliate these challenges. By discussing various benchmark semiconductor materials such as 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) and perylenetetracarboxyldiimide derivatives (PTCDI-C_n), we demonstrate the solvent exchange-based crystallization methods can modulate supramolecular aggregation, promote nucleation formation, improve semiconductor alignment, change crystal dimensionality, and enhance charge transport. We believe this work provides useful comprehension of employing the solvent exchange methods to powerfully regulate the crystallization, morphology and mobility of organic semiconductors, and thereby casts light on high performance organic electronic applications. Graphic Abstract: [Figure not available: see fulltext.].