A Computational Insight on Designing Low Electronic Energy Gap
(Benzothiadiazole/ Benzoselenadiazole – Pyrrole) copolymers
Abstract
Organic conductive polymers have great significance due to their wide
range of applications in optoelectronics and material sciences. In this
study, pyrrole-benzothiadiazole/benzoselenadiazole based type green
polymers were undertaken computational work to investigate the
solubility of polymers. Structural, electronic, and optical properties
of eight different polymers were predicted using DFT and TD-DFT at
B3LYP/6-31G level on semi-empirical PM6-optimized geometries. It has
been shown that the calculation results of synthesized green polymers
are in great agreement with the experimental results. Alkylated
4,7-di(1H-pyrrol-2-yl)benzo-[c][1,2,5]thiadiazole (PB1) and
4,7-di(1H-pyrrol-2-yl)benzo[c][1,2,5]selenadiazole (PB7)
monomers were studied to investigate the effect of alkyl chains on their
electronic and optical properties. Butyl substituted more soluble
polymers were shown to have low electronic energy gaps (1.27-1.55 eV).
Moreover, the electronic energy gap values of the studied polymeric
structures are in the appropriate range of technological applications
(1.24-2.18 eV). The approach utilized in this study can be used to
design new semi-conducting polymers.