Synthesis and Some Electrochemical Properties of Carbazole Derivative Monomers for Optoelectronic Device Design

Low-cost instruments are used to achieve high sensitivity, accuracy and precision with electrochemical techniques, making them the most suitable analytical methods used to investigate the electrochemical properties of a new molecule. Among these techniques, cyclic voltammetry, which is widely employed, allows for the determination of electronic characteristics such as molecular energy levels and orbital structure, redox properties, sensor capabilities, surface activity, and more. The carbazole molecule can undergo derivatization from various positions, allowing for alterations in its electrical and optical properties. These compounds serve as heterocyclic building blocks that can be utilized as materials for organic sensitizers and semiconductors in optoelectronic devices. Due to the presence of a hydrogen atom in the nitrogen-hydrogen (N-H) bond within the carbazole structure, which can be replaced with different functional groups, carbazole is highly suitable for nitrogen-based derivatization studies. In this study, two different carbazole monomers (IIa and IIIa), which could be potential optoelectronic, were synthesized using the Ullman and Suzuki-Miyaura reaction and characterized using 1H NMR, 13C NMR, UV-Vis, and Flouresence spectroscopy techniques. The cyclic voltammetry experiments were performed using three different working electrodes (Au, Gc, Pt disk electrodes) for each compound. Since the optimum oxidation of the compounds was obtained from the voltammograms on the gold disk electrode, this electrode was used in the calculation of energy levels. HOMO and Eg values of the compounds were deduced from cyclic voltammetry experiments and the optical absorption bands, respectively.