Synthesis, Characterization, and Study of Electrochemical Behavior of N-alkyl Substituted Polycarbazole Derivatives

Abstract

Poly(9-dodecylcarbazole) (PDDC) and poly[(9-dodecylcarbazole)-co-thiophene] (PDDCT) were synthesized via oxidative coupling method using FeCl₃ and the polymers exhibited good solubility in polar aprotic solvents. The synthesized polymers were characterized using UV-visible, FTIR, ¹H-NMR spectroscopic techniques. The polymers exhibited thermal stability up to 300°C. The absorption spectra showed the maximum absorption peak at 414 and 443 nm (λ_max), respectively, for PDDC and PDDCT. The electrochemical analysis revealed that the band gaps calculated for PDDC and PDDCT are 2.21 eV and 1.91 eV, respectively. The study of anodic peak current against scan rate showed that the electrochemical process is diffusion-limited.

Keywords:

• band gap
• oxidative coupling
• polycarbazole
• semiconducting

Acknowledgments

We are thankful to the Defence Research Development Organization (DRDO), India, for their research grant (ERIP/ER/0403454/M/01 dt 15.11.2004).

Notes

^a Φ_ox and Φ_red are the onset oxidation and reduction potential calculated from cyclic voltammogram.

^b The optical band gap was obtained from empirical formula, E_g = 1240/λ_edge, in which λ_edge is the onset value of the absorption spectrum in the longer wavelength direction.