Solvent Exchange in Controlling Semiconductor Morphology

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

Automated summary

Recent studies have shown significant advancements in charge carrier mobilities in solution processed, small molecular organic semiconductors, paving the way for their promising applications in organic electronic devices. However, the in-solution crystallization of these semiconductors poses challenges such as crystal misorientation, grain boundary, and mobility variation. This article discusses the effects of these issues on charge transport and explores the use of solvent exchange methods to mitigate these challenges, highlighting the benefits in optimizing the semiconductor morphology. The study demonstrates that solvent exchange-based crystallization methods can effectively modulate supramolecular aggregation, improve semiconductor alignment, and enhance charge transport, offering insights for high performance organic electronic applications.