Recently, the research in solution-based, small-molecule organic semiconductors has achieved great progress, although their application in organic electronics devices is still restricted by a variety of issues, including crystal misorientation, morphological nonuniformity and low charge-carrier mobility. In order to overcome these issues, hybrid material systems that incorporate both organic semiconductors and additives have been successfully demonstrated to control crystal growth and charge transport of the organic semiconductors. In this work, we first review the recent advances in the charge-carrier mobility of the organic semiconductors, followed by a comparison of the different additives that have been reportedly blended with the semiconductors, including polymeric additives, small-molecule additives and nanoparticle based additives. Then we will review the important nanoparticles employed as additives to blend with solution-based, organic semiconductors, which effectively improved the semiconductor crystallization, enhanced film uniformity and increased charge transport. By discussing specific examples of various well-known organic semiconductors such as 6, 13-bis (triisopropylsilylethynyl) pentacene (TIPS pentacene), we demonstrate the essential relationship among the crystal growth, semiconductor morphology, dielectric properties, and charge-carrier mobilities. This work sheds light on the implementation of nanoparticle additives in high-performance organic electronics device application.
Lateral and vertical phase separations play critical roles in the performance of the next-generation organic and hybrid electronic devices. A method is demonstrated here to switch between lateral and vertical phase separations in semiconducting 6,13-bis(triisopropylsilylethynyl) pentacene (TIPSE pentacene)/polymer blend films by simply varying the alkyl length of the polyacrylate polymer component. The phase separation modes depend on intermolecular interactions between small molecule TIPSE pentancene and polymer additives. The blend film with a dominant vertical phase separation exhibits a significant enhancement in average mobility and performance consistency of organic thin-film transistors.