Partially Oxygen-Bridged Triphenylamines with a Quasiplanar Structure as a Key Scaffold for Hole-Transporting Materials

Abstract

Organic electronics have attracted much attention as they promise great potential for applications as lightweight and flexible electronic devices. In order to improve the performance of such devices, the development of improved charge-transporting materials is of paramount importance. The molecular design of such materials should aim to control not only the electronic structure, but also the molecular orientation of these compounds in the solid state. For the development of materials with improved charge-transporting properties, we focused on compounds with a quasiplanar structure, i.e. a structure that is slightly twisted from planarity. As a model skeleton, we designed and synthesized partially oxygen-bridged triarylamines. On the basis of their quasiplanar skeletons as key units, we have developed hole-transporting materials (HTMs) that were subsequently used in organic electronics devices, such as OLEDs and perovskite solar cells, and led to improved performances. This account article illustrates our endeavors regarding the development of such functional π-conjugated materials, with a focus on facile and efficient synthetic strategies.