Studying the electronic and charge transport properties of two cyclocarbazole derivates

Abstract

Molecular systems have proven to be efficient active materials in electronics, being possible alternatives to the inorganic semiconductors used nowadays in electronic devices. For this reason, organic electronics has emerged as a research field with great potential and interest. In this project, an experimental and theoretical study of two carbazole-based macrocycles is presented (Figure 1). Specifically, we investigated the impact of the inclusion of acetylene groups on the electronic and molecular structures of these macrocycles, as well as their potential as charge transporting materials. The first studied compound (Cz) is composed by four carbazole groups linked at their para position with respect to the nitrogen atom[1]. In the second compound (ACz), the carbazole units are connected through ethynylene groups[2]. For this study, Raman and UV-Vis absorption spectroscopies have been used in combination with theoretical calculations based on the density functional theory (DFT). In addition, the two studied compounds have been implemented in organic field-effect transistors (OFETs), to assess their potential as active materials in organic electronics. Overall, the inclusion of ethynylene groups as π-conjugated spacers is found to be a good strategy to improve the electronic delocalization in macrocycles.