Iron (II) Metallo-Supramolecular Polymers Based on Thieno[3,2- b]thiophene for Electrochromic Applications

Andrei Chernyshev; Udit Acharya; Jiří Pfleger; Olga Trhlíková; Jiří Zedník; Jiří Vohlídal

doi:10.3390/polym13030362

Iron (II) Metallo-Supramolecular Polymers Based on Thieno[3,2- b]thiophene for Electrochromic Applications

Polymers (Basel). 2021 Jan 23;13(3):362. doi: 10.3390/polym13030362.

Authors

Andrei Chernyshev¹, Udit Acharya^{2

3}, Jiří Pfleger², Olga Trhlíková², Jiří Zedník¹, Jiří Vohlídal¹

Affiliations

¹ Faculty of Science, Department of Physical and Macromolecular Chemistry, Charles University, Hlavova 2030, 128 40 Prague 2, Czech Republic.
² Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic.
³ Faculty of Mathematics and Physics, Charles University, 121 16 Prague 2, Czech Republic.

Abstract

Four new bis(tpy) unimers with different linkers between the thieno[3,2-b]thiophene-2,5-diyl central unit and terpyridine-4'-yl (tpy) end-groups: no linker (Tt), ethynediyl (TtE), 1,4-phenylene (TtPh) and 2,2'-bithophene-5,5'-diyl (TtB) are prepared, characterized, and assembled with Fe²⁺ ions to metallo-supramolecular polymers (Fe-MSPs). The Fe-MSP films prepared by spin-casting on Indium Tin Oxide (ITO) glass are characterized by atomic force microscope (AFM) microscopy, cyclic voltammetry, and UV/vis spectroscopy and studied for their electrochromism and effect of the unimer structure on their electrochromic performance. Of the studied MSPs, Fe-Tt shows the highest optical contrast as well as coloration efficiency (CE = 641 cm² C^-1) and the fastest optical response. This makes it an excellent candidate for possible use in electrochromic devices.

Keywords: electrochromism; field responsive polymer; gel electrolyte; metallo-supramolecular polymer; self-assembly; terpyridine; unimer.