Selenophene as a Bridge in Molecular Architecture of Benzotriazole Containing Conjugated Copolymers to Gain Insight on Optical and Electrochemical Properties of Polymers

GRAPHICAL ABSTRACT

Abstract

Polymers containing selenophene as a π bridge; poly(2-(2-octyldodecyl)-4-(selenophen-2-yl)-7-(5-(thiophen-2-yl)selenophen-2-yl)-2H-benzo[d][1,2,3]triazole) (P1)

and poly(2-(2-octyldodecyl)-4-(5-phenylselenophen-2-yl)-7-(selenophen-2-yl)-2H-benzo[d][1,2,3]triazole (P2) were synthesized via Stille and Suzuki coupling reactions, respectively. Optical and electrochemical properties were investigated and comparisons with their thiophene analogs were done. Selenophene substitution resulted in low band gap and red shifted absorption, fast switching times (less than 1 s) with reasonable optical contrast. Switching time of P2 was 0.2 second which is the fastest switching time regarding benzotriazole-based polymers. Photovoltaic properties of P1 and P2 were investigated. The optimized devices showed 0.45% and 0.75% power conversion efficiency, respectively.

Keywords:

• Selenophene
• electrochromism
• benzotriazole
• substitution effect
• donor-acceptor