Synthesis and Characterization of 3,6 - Disubstituted Carbazole Containing Fluorene and DSSC Applications

Abstract

Heterocyclic compounds containing nitrogen are regarded as essential structural motifs present in numerous natural products and organic materials. Within this group, carbazoles are important hetero-aromatic molecules which play a significant role in the development of materials with various functionalities. Carbazole derivatives play a crucial role in various organic electronic devices such as organic transistors (OTFTs), organic light-emitting diodes (OLEDs), and organic solar cells. In this study, the solubility of the carbazole nucleus, which initially had limited solubility in organic solvents, was increased by adding an octyl group. Next, a carbazole-based compound 3,6-di(fluorene-9)-9-octyl-9H-carbazole (IV) was synthesized via the Suzuki-Miyaura cross-coupling reaction (Figure 1). The photophysical and thermal properties of this compound were determined by UV-Vis, thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The HOMO and LUMO energy levels and the optical band gap (Eg,opt) were obtained by cyclic voltammetry (CV) and absorption bands. TiO2-based dye-sensitized solar cells (DSSCs) were fabricated using compound IV. The photoelectrochemical properties of the resulting TiO2-DSSCs were measured.