The trade-off between electrochromic stability and contrast of a thiophene-Quinoxaline copolymer
Journal article, 2017

The stability of organic electrochromic devices is a crucial issue for their applications. However, until now the degradation mechanism of electrochromic materials are still not fully understood especially for electrochromic conjugated polymers (ECPs). To improve device stability, intensive investigation on the degradation mechanism of ECPs is urgently needed. Here we report our study on the electrochromic degradation in a thiophene-quinoxaline copolymer: poly [2,3-bis-(3-octyloxyphenyl) quinoxaline-5,8diyl- alt-thiophene-2,5-diyl] (TQ1). The results of X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectra (UPS) and UV-vis transmission spectra reveal that there are three main factors during the electrochromic degradation of TQ1. The first one is anion (ClO4-) irreversibly deep trapped, while the second is peroxidation of the thiophene group in TQ1. Both factors reduce the conductivity and electrochromism of TQ1. The third is structural relaxation resulting lager conjugated system of TQ1 molecules in film, which is gradually developed during 400 cycling of CV at a narrow potential range (01 V). When a potential range 0-0.7 V is applied, all three factors are prohibited, no electrochromism degradation is observed anymore, although the contrast becomes smaller. Our investigation systematically discloses the degradation mechanism during the electrochemistry processing of a ECP (TQ1), demonstrating the significance of trade-off between the electrochromic stability and contrast of the ECP.

Electrochemistry

Degradation

Thiophene-quinoxaline copolymer

Electrochromic

Stability

Author

X. Xing

Linköping University

C. F. Wang

Linköping University

X. J. Liu

Linköping University

L. Q. Qin

Linköping University

Ergang Wang

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

Fengling Zhang

Linköping University

Electrochimica Acta

0013-4686 (ISSN)

Vol. 253 530-535

Subject Categories

Materials Chemistry

DOI

10.1016/j.electacta.2017.09.068

More information

Latest update

2/28/2018