Synthesis and investigation of novel organic semiconductors based on diketopyrrolopyrrole (DPP) for optoelectronic applications

Abstract

Organic semiconductors that inherently facilitate solution processing have attracted much interest for near-future electronic devices such as organic photovoltaics (OPVs) and organic field-effect transistors (OFETs) due to diverse advantages including low cost fabrication, mechanical flexibility, and tunable optoelectronic properties. In spite of significant studies on material science and device physics related to organic semiconductors, a better understanding of both the efficient synthesis of novel molecules and the development of new fabrication techniques is highly recommended for further development of organic electronics. Until now, even where solution-processable polymeric semiconductors are concerned, impressive progress has been achieved only in developing p-type conjugated polymers. Solution-processable n-type and ambipolar polymers largely remain elusive. In this regard, the present research is focused on developing high electron-affinity semiconductors by a structural modification of electron accepting unit. In addition, although tremendous efforts have been focused on the design of building blocks for polymer backbones, relatively little attention has been paid to the molecular engineering of polymer side chains. Thus, the present research investigates modifications of side chains. The work begins with a brief overview of the organic semiconductors followed by introductions of palladium-catalyzed aryl-aryl cross-coupling reactions, diketopyrrolopyrrole (DPP), and side chains as well as short explanations of organic electronics. Then, research results that have contributed to the development of high-performance n-type and ambipolar semiconducting polymers are presented as well as followed by polymerization methodology and small molecule-based organic solar cells.