Selenophene-bearing low-band-gap conjugated polymers: tuning optoelectronic properties via fluorene and carbazole as donor moieties

Date

2020-05-01

Author

Yasa, Mustafa
GÖKER, SEZA
Toppare, Levent Kamil

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

In this study, two donor-acceptor (D-A)-type conjugated polymers, namely PQSeCz and PQSeFl, were designed and synthesized. Selenophene was incorporated as the pi-bridge and quinoxaline as an acceptor unit, while carbazole and fluorene were used as the donor units. Polymers were synthesized via palladium-catalyzed Suzuki polymerization reaction. All molecules were characterized by H-1 and C-13 NMR spectroscopy. The weight and number average molecular weights of the two polymers were determined by gel permeation chromatography. Electrochemical and spectroelectrochemical characterizations of the polymers were performed to investigate their optoelectronic properties. Oxidation potentials were 1.15 V/0.82 V and 1.11 V/0.82 V for PQSeCz and PQSeFl, respectively, while reduction potentials were - 1.26 V/- 1.14 V and - 1.48 V/- 1.20 V, respectively. In the visible region, maximum absorption wavelengths for the two polymers were 551 nm and 560 nm, respectively. Optical band gaps (Egop) were found from the lowest energy pi-pi* transition onsets as 1.67 eV for PQSeCz and 1.51 eV for PQSeFl, respectively. Both polymers showed good solubility in common solvents.

Subject Keywords

Materials chemistry, General chemistry, Polymers and plastics, Condensed matter physics, Conjugated polymer, Quinoxaline, Selenophene, Fluorene, Carbazole, Band gap, Suzuki coupling

URI

https://hdl.handle.net/11511/38299

Collections

Department of Chemistry, Article