Synthesis of new carbazole monomer for organic transistors application

Abstract

The potential and advantages of organic semiconductors as low-cost flexible electronics have sparked immense research in recent years. This project aims to research the synthesis of 5-dodecyl-5H-naphthol[2,3-b]carbazole-7,12-dione which could be a potential organic conducting material for future possible applications as organic transistors. To obtain 5-dodecyl-5H-naphthol[2,3-b]carbazole-7,12-dione, the synthesis of 9-dodecyl-9H-carbazole, 2-(9-dodecyl-9H-carbazole-3-carbonyl)benzoic acid and 5- dodecyl-5H-naphthol[2,3-b]carbazole-7,12-dione were first carried out. Alkylation, Friedel-Crafts acylation and intramolecular Friedel-Crafts reaction were the mechanisms to obtain the respective small molecules. The reactions were successfully carried out and the molecules existences were confirmed using nuclear magnetic resonance (NMR) (analyzing structure) and MALDI-TOF mass spectroscopy (analyzing molecular weight). Further characterization was done using ultraviolet-visible spectroscopy (UV- Vis) (absorption) and fluorescence spectroscopy (emission). Another potential organic material 2,2'-(5-dodecyl-5H-naphtho[2,3-b]carbazole-7,12-diylidene)dimalononitrile was synthesised. The molecule has a similar structure to tetracyanoquinodimethane (TCNQ), which has been widely studied for its high conductivity when fused with tetrathiafulvalene (TTF) to produce molecular organic conductors known as organic metals.